CN113659338B - Antenna device and electronic device - Google Patents

Abstract

The application provides an antenna device and an electronic device. The antenna device includes: a first antenna unit and a second antenna unit disposed adjacently; a first decoupling network having an input port, an output port, a first connection port, and a second connection port; the output port is connected with the first antenna unit, and the input port is used for being connected with a first feed source; a second decoupling network having an input port, an output port, a first connection port, and a second connection port; the output port of the second decoupling network is connected with the second antenna unit, and the input port of the second decoupling network is used for being connected with a second feed source; a first decoupling transmission line connecting a first connection port of the first decoupling network with a first connection port of the second decoupling network; and a second decoupling transmission line connecting the second connection port of the first decoupling network with the second connection port of the second decoupling network. The application can improve the isolation degree of the antenna device and the electronic equipment.

Description

Antenna device and electronic device

Technical Field

The present application relates to the technical field of antenna decoupling, and in particular to an antenna device and an electronic device using the antenna device.

Background technique

Antennas can efficiently transmit and receive electromagnetic waves and are an indispensable component of wireless communication systems. However, with the advancement of science and technology, a single antenna is unable to meet the increasing performance requirements. In order to solve the problems of poor directivity and low radiation gain of a single antenna, several antenna units with the same radiation characteristics can be arranged in a certain geometric structure to form an array antenna, thereby enhancing the radiation performance of the array antenna and generating a more flexible radiation pattern to meet the needs of different scenarios.

Summary of the invention

In one aspect, the present application provides an antenna device, which includes: a first antenna unit and a second antenna unit arranged adjacent to each other; a first decoupling network, the first decoupling network having an input port, an output port, a first connection port, and a second connection port; the output port is connected to the first antenna unit, and the input port is used to connect to a first feed source; a second decoupling network, the second decoupling network having an input port, an output port, a first connection port, and a second connection port; the output port of the second decoupling network is connected to the second antenna unit, and the input port of the second decoupling network is used to connect to a second feed source; a first decoupling transmission line, the first decoupling transmission line connecting the first connection port of the first decoupling network and the first connection port of the second decoupling network; and a second decoupling transmission line, the second decoupling transmission line connecting the second connection port of the first decoupling network and the second connection port of the second decoupling network.

On the other hand, the present application also provides an electronic device, which includes: a housing; a display screen assembly connected to the housing and forming a housing space with the housing; a feed source arranged in the housing space; and an antenna device, at least partially arranged in the housing space. The antenna device includes: a plurality of antenna units; a plurality of decoupling networks corresponding one to one with the plurality of antenna units, wherein each decoupling network has an input port, an output port, a first connection port, and a second connection port; the output port is connected to the corresponding antenna unit, and the input port is connected to the feed source; a first decoupling transmission line, the first decoupling transmission line is connected between adjacent first connection ports of the decoupling network; a second decoupling transmission line, the second decoupling transmission line is connected between adjacent second connection ports of the decoupling network.

Since the present application sets a first decoupling network and a second decoupling network between two adjacent antenna units, and the first decoupling transmission line and the second decoupling transmission line are connected between the first decoupling network and the second decoupling network, a part of the signal emitted from the feed source is transmitted to the antenna unit via the first decoupling network, and another part of the signal is transmitted to the second decoupling network via the first decoupling network and the first decoupling transmission line and the second decoupling transmission line to reach the adjacent antenna unit, thereby offsetting the coupling between the two antenna units to a certain extent and improving the isolation of the multi-antenna system. Furthermore, the present application introduces the concept of a decoupling network below the antenna unit, without changing the structure of the array antenna unit. It only needs to configure the length of the first decoupling transmission line and the second decoupling transmission line and the scattering parameters (i.e., S parameters) of the four-port network to adjust the coupling between the antenna units, that is, to reduce the mutual coupling between the antenna units, expand the scanning angle, and improve the scanning gain.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work, including:

FIG1 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application;

FIG2 is a schematic diagram of the decoupling principle for an array antenna according to an embodiment of the present application;

FIG3 is a schematic diagram of a decoupling structure for an array antenna according to an embodiment of the present application;

FIG4 is a schematic diagram of the structure of a first decoupling network according to an embodiment of the present application;

FIG5 is a schematic diagram of the structure of a second decoupling network according to an embodiment of the present application;

FIG6 is a schematic flow chart of a decoupling method for an array antenna according to an embodiment of the present application;

FIG7 is a schematic diagram of the three-dimensional structure of an electronic device according to an embodiment of the present application;

FIG8 is a perspective view of an antenna device according to an embodiment of the present application;

FIG9 is a top view of the antenna device of FIG8;

FIG10 is a bottom view of the antenna device of FIG8;

11 is a partial schematic diagram of the antenna device of FIG. 10 , which shows the arrangement of the first decoupling network and the second decoupling network of the antenna device and the first decoupling transmission line and the second decoupling transmission line connected therebetween;

FIG12 is a schematic diagram of a layered structure of an antenna device according to an embodiment of the present application, wherein two antenna units are shown;

FIG13 is a schematic diagram of an antenna device according to another embodiment of the present application;

FIG14 shows a comparison curve of the coupling coefficient between two antenna units in the antenna device according to the embodiment of the present application before and after the decoupling network is connected;

FIG15 shows a comparison curve of the reflection coefficient of the antenna unit in the antenna device according to the embodiment of the present application before and after the decoupling network is connected;

FIG16 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 0° before the decoupling network is connected;

FIG17 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 0° after the decoupling network is connected;

FIG18 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 45° before the decoupling network is connected;

FIG19 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 45° after the decoupling network is connected;

FIG20 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 50° before the decoupling network is connected;

FIG21 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the beam is scanned to 50° after the decoupling network is connected;

FIG. 22 shows a curve of the radiation performance of the antenna device according to the embodiment of the present application when the decoupling network is connected and the beam is scanned to 55°.

Detailed ways

The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

Array antennas, especially those with small spacing, have the problem of strong mutual coupling. The mutual coupling between antenna units greatly affects the matching characteristics and spatial radiation characteristics of the antenna units and their arrays, which is specifically manifested in the following points.

(1) Directional pattern: The current distribution on the antenna unit changes due to mutual coupling, causing part of the radiated energy to be further coupled to other antenna units, part of which is absorbed and consumed by the termination load, while the other part of the energy is radiated again. Therefore, the directivity pattern of the antenna unit will be distorted. The termination load mentioned here is a parameter equivalent to the rear end of the antenna feed source; when drawing the equivalent circuit, the entire rear end of the antenna feed source can be replaced by a resistor, which can be called the termination load.

(2) Input impedance: Due to the influence of mutual coupling, the input impedance of the antenna unit in the array will change and be different from the input impedance of the antenna unit in an isolated environment. Therefore, the matching conditions of the antenna units in each array are different and the matching characteristics will be affected.

(3) Gain: There is heat loss and reflection loss caused by characteristic impedance mismatch in the antenna unit, which makes the radiation power of the antenna unit smaller than the transmission power. The reflection coefficient will change under the action of mutual coupling, so the gain of the antenna unit is affected.

In the relevant technology, the following five methods are usually used to solve the influence of mutual coupling effect on the radiation pattern, input impedance, gain and other characteristics of the antenna unit: defective ground structure (DGS-Defected Ground Structure) decoupling method, neutralization line method (NLT-Neutralization Line Technique) decoupling method, band-stop filtering decoupling method, electromagnetic band gap structure (EBG, Electromagnetic Band Gap) decoupling method, metamaterial decoupling method (MDT, Metamaterial Decoupling Technique).

However, the above methods are all aimed at studying the methods of eliminating coupling between antenna units, and fail to accurately define and control the coupling effect between antenna units.

The present application provides an electronic device whose array antenna can customize the coupling effect between antenna units and control the radiation pattern of the antenna units through the design of the coupling effect, such as widening the scanning angle, improving the scanning gain, eliminating the scanning blind area, etc.

The electronic device may be a mobile phone, a tablet computer, a PDA (Personal Digital Assistant), a POS (Point of Sales), a vehicle-mounted computer, a CPE (Customer Premise Equipment), etc. The present application is introduced below using a mobile phone as an example.

As shown in Figure 1, the mobile phone 100 may include: RF (Radio Frequency) circuit 101, memory 102, central processing unit (CPU) 103, peripheral interface 104, audio circuit 105, speaker 106, power management chip 107, input/output (I/O) subsystem 108, touch screen 109, other input/control devices 110 and external port 111. These components communicate through one or more communication buses or signal lines 112.

It should be understood that the illustrated mobile phone is only one example of an electronic device, and that the mobile phone 100 may have more or fewer components than those shown in the figure, may combine two or more components, or may have a different configuration of components. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

The following is a detailed introduction to the various components of the mobile phone 100 in conjunction with FIG. 1 .

The radio frequency (RF) circuit 101 is mainly used to establish communication between the mobile phone and the wireless network (i.e., the network side) to realize data reception and transmission between the mobile phone and the wireless network. For example, sending and receiving short messages, emails, etc. Specifically, the RF circuit 101 receives and sends RF signals, which are also called electromagnetic signals. The RF circuit 101 converts electrical signals into electromagnetic signals or converts electromagnetic signals into electrical signals, and communicates with the communication network and other devices through the electromagnetic signals. The RF circuit 101 may include known circuits for performing these functions, including but not limited to an antenna system with an antenna array, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC (COder-DECoder) chipset, a subscriber identity module (Subscriber Identity Module, SIM), and the like.

The memory 102 can be accessed by the CPU 103, the peripheral interface 104, etc. The memory 102 may include a high-speed random access memory and a non-volatile memory, such as one or more disk storage devices, flash memory devices, or other volatile solid-state storage devices.

The CPU 103 executes various functional applications and data processing of the electronic device by running the software programs and modules stored in the memory 102 .

The peripherals interface 104 may connect the input and output peripherals of the device to the CPU 103 and the memory 102 .

The I/O subsystem 108 can connect the input and output peripherals on the device, such as the touch screen 109 and other input/control devices 110, to the peripheral interface 104. The I/O subsystem 108 may include a display controller 1081 and one or more input controllers 1082 for controlling other input/control devices 110. Among them, the one or more input controllers 1082 receive electrical signals from other input/control devices 110 or send electrical signals to other input/control devices 110. Other input/control devices 110 may include physical buttons (press buttons, rocker buttons, etc.), dials, slide switches, joysticks, and click wheels. It is worth noting that the input controller 1082 can be connected to any of the following: a keyboard, an infrared port, a USB interface, and a pointing device such as a mouse.

The touch screen 109 is an input interface and an output interface between the user terminal and the user, and displays visual output to the user. The visual output may include graphics, text, icons, videos, etc.

The display controller 1081 in the I/O subsystem 108 receives an electrical signal from the touch screen 109 or sends an electrical signal to the touch screen 109. The touch screen 109 detects contact on the touch screen, and the display controller 1081 converts the detected contact into interaction with a user interface object displayed on the touch screen 109, that is, realizes human-computer interaction. The user interface object displayed on the touch screen 109 may be an icon for running a game, an icon for connecting to a corresponding network, etc. It is worth noting that the device may also include an optical mouse, which is a touch-sensitive surface that does not display a visual output, or an extension of a touch-sensitive surface formed by the touch screen.

The audio circuit 105 is mainly used to receive audio data from the peripheral interface 104 , convert the audio data into an electrical signal, and send the electrical signal to the speaker 106 .

The speaker 106 is used to restore the voice signal received by the mobile phone 100 from the wireless network through the RF circuit 101 to sound and play the sound to the user.

The power management chip 107 is used to provide power and manage power for the CPU 103 , the I/O subsystem 108 , and the hardware connected to the peripheral interface 104 .

The following is an introduction to the array antenna in the antenna system of the RF circuit 101 of the electronic device. The array antenna generally includes a plurality of closely arranged antenna units. In at least two adjacent antenna units, each antenna unit is connected to the feed source via a decoupling network. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

This embodiment uses two adjacent antenna units 10 and 20 as examples to introduce the present application. As shown in FIG2 , it is a schematic diagram of the decoupling principle for an array antenna in an embodiment of the present application, and the array antenna includes adjacent antenna units 10 and antenna units 20. The radiation characteristics of the antenna unit 10 and the antenna unit 20 may be the same or different. The antenna unit 10 may receive an excitation current from a feed source (RF transceiver) of an electronic device, and after amplification, filtering, matching and tuning, the antenna unit 10 is excited to resonate at a corresponding frequency, thereby generating an electromagnetic wave signal of a corresponding frequency, and coupling with an electromagnetic wave signal of the same frequency in free space to achieve signal transmission. The antenna unit 10 can also resonate with the antenna unit of the corresponding frequency under the excitation of the excitation signal to couple the electromagnetic wave signal of the same frequency from the free space, thereby forming an induced current on the antenna unit 10, and the induced current enters the RF transceiver after filtering and amplification.

The decoupling networks corresponding to the two adjacent antenna units 10 and 20 are connected to each other, wherein the antenna unit 10 corresponds to the first decoupling network 31, and the antenna unit 20 corresponds to the second decoupling network 31'. The first decoupling network 31 and the second decoupling network 31' are both four-port networks. The first decoupling network 31 has an input port (a ₁ , b ₁ ) connected to a feed source, an output port (a ₂ , b ₂ ) connected to the antenna unit 10, and a first connection port (a ₃ , b ₃ ) and a second connection port (a ₄ , b ₄ ) for connecting to the second decoupling network 31'. The second decoupling network 31' has an input port (a' ₁ , b' ₁ ) connected to a feed source, an output port (a' ₂ , b' ₂ ) connected to the antenna unit 20, and a first connection port (a' ₃ , b' ₃ ) and a second connection port (a' ₄ , b' ₄ ) for connecting to the first decoupling network 31. The transmission line with a length of _d1 can form an output port ( _a2 , _b2 ) and has a characteristic impedance _Z0 ; the transmission line with a length of _d2 can form an output port ( _a'2 , _b'2 ) and has a characteristic impedance _Z0 . The first decoupling transmission line with a length of _d3 connects the first connection port ( _a3 , _b3 ) of the first decoupling network 31 and the first connection port ( _a'3 , _b'3 ) of the second decoupling network 31' and has a characteristic impedance _Z3 ; the second decoupling transmission line with a length of _d4 connects the second connection port ( _a4 , _b4 ) of the first decoupling network 31 and the second connection port ( _a'4 , _b'4 ) of the second decoupling network 31' and has a characteristic impedance _Z4 . In addition, a ₁ , a ₂ , a' ₁ , a' ₂ , a ₃ , a ₄ , a' ₃ , a' ₄ are incident voltage wave amplitudes, and b ₁ , b ₂ , b' ₁ , b' ₂ , b ₃ , b ₄ , b' ₃ , b' ₄ are reflected voltage wave amplitudes. It is worth mentioning that the "input port" and "output port" in the embodiments of the present application are named only from the perspective of the antenna unit 10 transmitting the signal. It can be understood that the antenna unit 10 can also receive signals. In this case, the above-mentioned "output port" can be used as an input port, and the above-mentioned "input port" can be used as an output port, that is, the naming of the "input port" and "output port" in the present application does not limit the properties of the port. It should also be pointed out that in FIG2 , a transmission line with characteristic impedance _Z0 is also shown on one side of the transmission line with length _d1 , but these two transmission lines correspond to the same wire in reality; similarly, the transmission line with length _d2 , the first decoupling transmission line with length _d3 , and the second decoupling transmission line with length _d4 should also be understood in the same way. Characteristic impedance _Z3 and characteristic impedance _Z4 can be set to be equal to characteristic impedance _Z0 . In addition, the characteristic impedance _Z0 is usually preset, for example, set to 50Ω.

As shown in FIG3 , it is a schematic diagram of a decoupling structure for an array antenna according to an embodiment of the present application, wherein at least a first decoupling network 31, a second decoupling network 31′, and a first decoupling transmission line 33 and a second decoupling transmission line 34 connected therebetween can constitute the decoupling structure for an array antenna according to the present application. In addition, the decoupling structure and the array antenna connected thereto can also form an antenna device according to the present application.

The following specifically introduces an example of the first decoupling network 31 corresponding to the antenna unit 10 in Figures 3 and 4. It can be understood that the second decoupling network 31' corresponding to the antenna unit 20 can be the same as the first decoupling network 31 corresponding to the antenna unit 10.

Specifically, as shown in FIG3 and FIG4 , the first decoupling network 31 is a four-port network. In one embodiment, the four-port network is a directional coupler, which may include a directional coupler body 310 and four transmission lines extending from the directional coupler body 310. The four transmission lines include a first transmission line 311, a second transmission line 312, a third transmission line 313, and a fourth transmission line 314. In addition, the first connection port (a ₃ , b ₃ ) of the directional coupler may be a coupling port or an isolation port; accordingly, the second connection port (a ₄ , b ₄ ) of the directional coupler may be an isolation port or a coupling port.

The directional coupler body 310 may include a fifth transmission line 315, a sixth transmission line 316, a seventh transmission line 317, and an eighth transmission line 318. The fifth transmission line 315, the sixth transmission line 316, the seventh transmission line 317, and the eighth transmission line 318 are connected end to end in a polygon to form a loop.

Among them, the first end of the first transmission line 311 is connected to the first end of the fifth transmission line 315, and the second end of the first transmission line 311 forms an input port connected to the feed source 40. The first end of the second transmission line 312 is connected to the second end of the fifth transmission line 315, and the second end of the second transmission line 312 forms an output port connected to the antenna unit 10. The first end of the third transmission line 313 is connected to the first end of the seventh transmission line 317, and the second end of the third transmission line 313 forms a first connection port connected to the first end of the first decoupling transmission line 33. The first end of the fourth transmission line 314 is connected to the second end of the seventh transmission line 317, and the second end of the fourth transmission line 314 forms a second connection port connected to the first end of the second decoupling transmission line 34. It is pointed out here that the first end and the second end of a transmission line mentioned in the text refer to the two opposite ends of the transmission line.

The third transmission line 313 and the fourth transmission line 314 can be designed to have a shorter length, for example, the length of the third transmission line 313 and the fourth transmission line 314 is only enough to connect with the first decoupling transmission line 33 and the second decoupling transmission line 34, and no longer has redundant length. This can reduce the impact on the length design of the first decoupling transmission line 33 and the second decoupling transmission line 34.

The characteristic impedance of the fifth transmission line 315 and the seventh transmission line 317 can be designed as Z ₁ , and the characteristic impedance of the sixth transmission line 316 and the eighth transmission line 318 can be designed as Z ₂ . In addition, the lengths of the fifth transmission line 315 , the sixth transmission line 316 , the seventh transmission line 317 and the eighth transmission line 318 can all be set to (1/4)λ, where λ is the wavelength.

As shown in Figures 3 and 5, the second decoupling network 31' corresponding to the antenna unit 20 can be the same as the first decoupling network 31 mentioned above. Specifically, the second decoupling network 31' is a four-port network. In one embodiment, the four-port network is a directional coupler, which may include a directional coupler body 310' and four transmission lines extending from the directional coupler body 310'. The four transmission lines include a first transmission line 311', a second transmission line 312', a third transmission line 313' and a fourth transmission line 314'. In addition, the first connection port ( _a'3 , _b'3 ) of the directional coupler can be a coupling port or an isolation port; accordingly, the second connection port ( _a'4 , _b'4 ) of the directional coupler can be an isolation port or a coupling port.

The directional coupler body 310' may include a fifth transmission line 315', a sixth transmission line 316', a seventh transmission line 317' and an eighth transmission line 318'. The fifth transmission line 315', the sixth transmission line 316', the seventh transmission line 317' and the eighth transmission line 318' are connected end to end in sequence to form a loop.

Among them, the first end of the first transmission line 311’ is connected to the first end of the fifth transmission line 315’, and the second end of the first transmission line 311’ forms an input port connected to the feed source 40’. The first end of the second transmission line 312’ is connected to the second end of the fifth transmission line 315’, and the second end of the second transmission line 312’ forms an output port connected to the antenna unit 20. The first end of the third transmission line 313’ is connected to the first end of the seventh transmission line 317’, and the second end of the third transmission line 313’ forms a first connection port connected to the second end of the first decoupling transmission line 33. The first end of the fourth transmission line 314’ is connected to the second end of the seventh transmission line 317’, and the second end of the fourth transmission line 314’ forms a second connection port connected to the second end of the second decoupling transmission line 34. The feed source 40 and the feed source 40’ may be the same feed source.

The third transmission line 313' and the fourth transmission line 314' can be designed to have a shorter length. For example, the third transmission line 313' and the fourth transmission line 314' only need to be connected to the first decoupling transmission line 33 and the second decoupling transmission line 34, and no longer have redundant length. This can reduce the impact on the length design of the first decoupling transmission line 33 and the second decoupling transmission line 34.

The characteristic impedance of the fifth transmission line 315' and the seventh transmission line 317' can be designed as _Z1 , and the characteristic impedance of the sixth transmission line 316' and the eighth transmission line 318' can be designed as _Z2 . In addition, the lengths of the fifth transmission line 315', the sixth transmission line 316', the seventh transmission line 317' and the eighth transmission line 318' can be set to (1/4)λ.

As shown in FIG3 , the first decoupling transmission line 33 and the second decoupling transmission line 34 are both connected between the first decoupling network 31 and the second decoupling network 31′. Specifically, the first end of the first decoupling transmission line 33 is connected to the first connection port of the first decoupling network 31, that is, connected to the second end of the third transmission line 313; the second end of the first decoupling transmission line 33 is connected to the first connection port of the second decoupling network 31′, that is, connected to the second end of the third transmission line 313′. Similarly, the first end of the second decoupling transmission line 34 is connected to the second connection port of the first decoupling network 31, that is, connected to the second end of the fourth transmission line 314; the second end of the second decoupling transmission line 34 is connected to the second connection port of the second decoupling network 31′, that is, connected to the second end of the fourth transmission line 314′.

3 to 5 , the characteristic impedance of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first transmission line 311′, the second transmission line 312′, the third transmission line 313′, the fourth transmission line 314′, the first decoupling transmission line 33, and the second decoupling transmission line 34 can be designed to be Z ₀ . In addition, the length of the first decoupling transmission line 33 can be set to d ₃ , and the length of the second decoupling transmission line 34 can be set to d ₄ .

It is noted that the terms "first", "second", and "third" in this application are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include at least one of the features.

The first decoupling transmission line 33 and the second decoupling transmission line 34 are used to transmit signals to offset the mutual coupling between the two antenna units 10 and 20. The coupling degree D1 between the two antenna units 10 and 20 can be defined by the scattering parameters (i.e., S parameters) of the first decoupling network 31 and the second decoupling network 31' and the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34. For example, if the coupling degree D1 between the two antenna units 10 and 20 is required to reach a preset coupling degree, the S parameters of the four-port network and the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 can be configured so that the coupling degree D1 between the antenna units 10 and 20 meets the preset coupling degree. It is pointed out here that the coupling degree D1 between the two antenna units 10 and 20 is inversely proportional to the isolation between the two antenna units 10 and 20; that is, the higher the isolation between the two antenna units 10 and 20, the lower the coupling degree D1 between the two antenna units 10 and 20.

It is easy to understand that when the first decoupling network 31 and the second decoupling network 31' adopt the same structure, their S parameters are also the same. Therefore, when the first decoupling network 31 and the second decoupling network 31' are the same, the relationship between the coupling degree D1 between the two antenna units 10 and 20 and the S parameter of the first decoupling network 31 and the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 can be obtained in the following way.

The matrix S ₀ of the S parameters of the first decoupling network 31 is:

Among them, S ₁₂ , S ₁₃ , and S ₃₁ are three S parameters when the first decoupling network 31 is a four-port network. Specifically, these three S parameters are mutual coupling coefficients, which can also be called coupling coefficients.

At the reference plane III (the reference plane III can be selected by mathematical deduction), the first connection port and the second connection port of the first decoupling network 31 are respectively connected to the first decoupling transmission line 33 and the second decoupling transmission line 34 with lengths of _d3 and _d4 . Therefore, the S parameter matrix S of the first decoupling network 31 can be obtained by the S parameter calculation in formula (1):

Wherein, e is a natural constant, j is a symbol for an imaginary number, k is a wave number, and S ₃₁ in equation (1) is equal to S ₁₃ in equation (2).

Before the first decoupling network 31 and the second decoupling network 31' are connected, they form an eight-port network, and the relationship between their S parameters is:

In formula (3), a1-a' ₄ is the incident voltage wave amplitude, and b1-b' ₄ is the reflected voltage wave amplitude.

in:

Write the matrix in equation (3) as a block matrix:

Wherein, S ₁₁ , S ₂₂ , and S ₂₁ are three S parameters of the four-port network, S ₁₁ is the reflection coefficient, and S ₂₁ is the mutual coupling coefficient.

Written in the form of a system of equations:

From formula (6), formula (4) can be simplified as:

[a ₂ ]＝[Γ]·[b ₂ ] (7)

Substituting formula (7) into formula (6), we can get:

From the second formula in formula (8), we can get:

[b ₂ ]＝{E-[S ₂₂ ][Γ]} ^-1 [S ₂₁ ][a ₁ ] (9)

In formula (9), E represents the unit matrix.

Substituting formula (9) into formula (8), we can get:

[b ₁ ]＝[S ₁₁ ][a ₁ ]+[S ₁₂ ][Γ]{E-[S ₂₂ ][Γ]} ^-1 [S ₂₁ ][a ₁ ] (10)

From formula (10), it can be obtained that the S parameter matrix S Four-port of the new four-port network (1, 2, 1', 2') formed by connecting the first decoupling network 31 and the second decoupling network 31' through the first decoupling transmission line 33 and the second decoupling transmission line ₃₄ is:

S _Four-port ＝[S ₁₁ ]+[S ₁₂ ][Γ]{E-[S ₂₂ ][Γ]} ^-1 [S ₂₁ ] (11)

It is pointed out here that the four ports of the new four-port network here refer to the four external ports ( _a1 , _b1 ), ( _a2 , _b2 ), ( _a'1 , _b'1 ) and ( _a'2 , _b'2 ) formed by connecting the first decoupling network 31 and the second decoupling network 31'.

Substituting the block matrices planned by equations (3) and (5) into equation (11), we can obtain the new S parameter matrix S _Four-port of the new four-port network:

Through digital calculation, the S parameter matrix S _Four-port of the new four-port network can be obtained as follows:

Adjust the port order of the new four-port network to 1→1'→2→2', then equation (13) becomes:

Rewrite equation (14) into the form of a block matrix:

Assume that the matrix S _array of the S parameters of the binary antenna formed by the two antenna units 10 and 20 is:

In formula (16), _S'12 is the amplitude of the initial isolation, that is, the strength of the isolation when the decoupling network is not connected between the two adjacent antenna units 10 and 20; _S'11 , _S'21 and _S'22 are the reflection coefficient, isolation and reflection coefficient of the input port ( _a1 , _b1 ) when the decoupling network is not connected between the two adjacent antenna units ₁₀ and ₂₀ , respectively.

After the first decoupling network 31 and the second decoupling network 31' are connected together through the first decoupling transmission line 33 and the second decoupling transmission line 34, the new four-port network is connected to the two antenna units 10 and 20 to form a two-port network. The S parameter matrix [S] of the two-port network is:

[S]＝[S ₁₁ ]+[S ₁₂ ][S _array ]{E-[S ₂₂ ][S _array ]} ^-1 [S ₂₁ ] (17)

It is pointed out here that the two ports of the two-port network here refer to the two ports (a ₁ , b ₁ ) and (a′ ₁ , b′ ₁ ) connected to the feed source remaining after the new four-port network is connected to the antenna units 10 and 20 .

Substituting the block matrices defined in equations (14) and (15) into equation (17), we can obtain:

It can be seen from formula (18) that by designing the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34, and the S parameters of the four-port network, the coupling degree D1 between the antenna units can be accurately defined. That is, after the required coupling degree is preset, the above formula can be expressed as:

Therefore, the lengths _d3 and d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 and the S parameters of the _four -port network can be configured so that the coupling degree D1 between the antenna units 10 and 20 meets the preset coupling degree.

For example, when the decoupling network is required to completely cancel the mutual coupling between the two antenna units 10 and 20, the preset coupling degree is set to 0, then:

Furthermore, when the preset coupling degree is set to 0, S ₁ ' ₂ can be expressed by the S parameters of the four-port network:

Assuming the coupling coefficient of the four-port network (eg, the aforementioned coupler) is S ₁₃ =D, then Substituting into the above formula, we can get:

Let k (d ₃ + d ₄ ) = 2π, φ _S12 = π,

Among them, _φs12 represents the phase of parameter _S12 of the four-port network, and _φs13 represents the phase of parameter _S13 of the four-port network.

Furthermore, the coupling degree D of the coupler can be calculated as follows:

Furthermore, the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 are respectively:

Wherein, φ ₂₁ is the phase of the isolation before decoupling, the value corresponding to pi is π, for example, 3.14, and S' ₁₂ is the amplitude of the isolation before decoupling.

It can be seen that the coupling degree D of the required directional coupler can be calculated according to _S'12 ; and the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 can also be calculated according to _φ21 . The sum of the length _d3 of the first decoupling transmission line 33 and the length _d4 of the second decoupling transmission line 34 is an integer multiple of the wavelength.

In addition, when the preset coupling degree is set to 0, the required directional coupler can also meet the following structural parameters:

Among them, the characteristic impedance _Z0 of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33 and the second decoupling transmission line 34 is usually preset, for example, set to 50Ω; h can be an impedance conversion factor. Therefore, according to the coupling degree D of the directional coupler calculated by formula (22), and then according to formula (24) and formula (25), the characteristic impedance of each branch of the directional coupler shown in Figure 4 can be determined, that is: the characteristic impedance _Z1 of the fifth transmission line 315 and the seventh transmission line 317, and the characteristic impedance _Z2 of the sixth transmission line 316 and the eighth transmission line 318. Furthermore, the line width of the transmission line corresponding to the characteristic impedance can be calculated so as to manufacture a directional coupler. Based on this method, the isolation of the multi-antenna system can be improved.

In some embodiments, the characteristic impedance of the transmission line can be made to meet the requirements by configuring the line width of the transmission line. For example, after the characteristic impedance Z ₀ of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33 and the second decoupling transmission line 34 is obtained according to the above relationship, the line width of these transmission lines can be configured so that their characteristic impedance meets the above characteristic impedance Z _0. For example, after determining the required thickness of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33 and the second decoupling transmission line 34, the relative dielectric constant of the PCB board material and the thickness of the dielectric layer, the line width of these transmission lines can be calculated according to the relationship between the characteristic impedance and the line width and the required characteristic impedance Z ₀ . Therefore, the line widths of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33 and the second decoupling transmission line 34 are configured according to the calculation result, thereby obtaining a plurality of transmission lines having the above characteristic impedance _Z0 .

Similarly, the line widths of the fifth transmission line 315 and the seventh transmission line 317 can be configured so that they meet the above required characteristic impedance Z _1. The line widths of the sixth transmission line 316 and the eighth transmission line 318 can be calculated based on the relationship between the characteristic impedance and the line width and the required characteristic impedance Z _2. Therefore, the line widths of the fifth transmission line 315 and the seventh transmission line 317 and the sixth transmission line 316 and the eighth transmission line 318 are configured based on the calculation results, thereby obtaining a plurality of transmission lines having the above characteristic impedances Z ₁ and Z ₂ .

It can be understood that the above four-port network can also be other forms of directional couplers, such as a coupled-line directional coupler, a miniaturized directional coupler, or a broadband directional coupler.

In combination with the above-mentioned decoupling structure, the present application further proposes a decoupling method for an antenna device. FIG6 is a flow chart of the decoupling method for an antenna device according to an embodiment of the present application.

As shown in FIG. 6 , the decoupling method may mainly include the following operations S101 - S102 .

Operation S101: Provide an antenna device, the antenna device comprising: a first antenna unit and a second antenna unit arranged adjacent to each other; a first decoupling network, the first decoupling network having an input port, an output port, a first connection port and a second connection port; the output port is connected to the first antenna unit, and the input port is used to connect to a first feed source; a second decoupling network, the second decoupling network having an input port, an output port, a first connection port and a second connection port; the output port of the second decoupling network is connected to the second antenna unit, and the input port of the second decoupling network is used to connect to a second feed source; a first decoupling transmission line, the first decoupling transmission line connects the first connection port of the first decoupling network and the first connection port of the second decoupling network; and a second decoupling transmission line, the second decoupling transmission line connects the second connection port of the first decoupling network and the second connection port of the second decoupling network.

As shown in FIG. 2 to FIG. 5 , the descriptions related to the antenna device in the present application are all applicable to the operation S101 and will not be repeated here.

Operation S102: defining a coupling degree between the first antenna unit and the second antenna unit according to a first length of the first decoupling transmission line, a second length of the second decoupling transmission line, and scattering parameters of the first decoupling network and the second decoupling network.

2 to 5 , the descriptions in the present application related to the first decoupling network 31 and the second decoupling network 31′ and the first decoupling transmission line 33 and the second decoupling transmission line 34 are all applicable to the operation S102 and will not be repeated here.

In one embodiment, the decoupling method may further include the following operation: setting the first antenna unit and the second antenna unit to have the same radiation characteristics.

In one embodiment, the decoupling method may further include the following operation: both the first decoupling network and the second decoupling network are designed as directional couplers.

In one embodiment, the decoupling method may further include the following operation: setting the first decoupling network and the second decoupling network to have the same scattering parameter.

In one embodiment, the decoupling method may further include the following operations: defining the coupling degree between the first antenna unit and the second antenna unit as D1, defining the first length of the first decoupling transmission line as _d3 , defining the second length of the second decoupling transmission line as _d4 , and defining the scattering parameters of the first decoupling network as _S12 and _S13 , wherein the following relationship is satisfied between these parameters:

Among them, e is a natural constant, j is the symbol for imaginary numbers, and k is the wave number.

In one embodiment, the decoupling method may further include the following operation: determining the coupling degree of the first decoupling network according to the strength of the isolation between the first antenna unit and the second antenna unit when the first decoupling network and the second decoupling network are not connected.

In one embodiment, the decoupling method may further include the following operations: defining the coupling degree of the first decoupling network as D, defining the strength of the isolation between the first antenna unit and the second antenna unit when the first decoupling network and the second decoupling network are not connected as S' ₁₂ , and these parameters satisfy the relationship defined by the above formula (22).

In one embodiment, the decoupling method may further include the following operations: the first decoupling network includes a fifth transmission line, a sixth transmission line, a seventh transmission line and an eighth transmission line connected in end to end order, the characteristic impedances of the fifth transmission line and the seventh transmission line are designed to be Z ₁ , the characteristic impedances of the sixth transmission line and the eighth transmission line are designed to be Z ₂ , and the characteristic impedances of the first decoupling transmission line and the second decoupling transmission line are designed to be Z ₀ ; wherein the coupling degree D of the first decoupling network and Z ₀ , Z ₁ and Z ₂ satisfy the relationship defined by the above equations (24) and (25).

In one embodiment, the decoupling method may further include the following operation: the lengths of the fifth transmission line, the sixth transmission line, the seventh transmission line and the eighth transmission line are all set to (1/4)λ, where λ is the wavelength.

In one embodiment, the decoupling method may further include the following operation: calculating the line widths _of the _fifth transmission line, the sixth transmission line, the seventh transmission line, the eighth transmission line, the first decoupling transmission line and the second decoupling transmission line according to the characteristic impedances Z 0 , _{Z 1} and Z 2 .

In one embodiment, the decoupling method may further include the following operation: a sum of a first length of the first decoupling transmission line and a second length of the second decoupling transmission line is an integer multiple of a wavelength.

In one embodiment, the decoupling method may further include the following operation: determining a first length of the first decoupling transmission line and a second length of the second decoupling transmission line based on a phase of isolation when the first decoupling network and the second decoupling network are not connected between the first antenna unit and the second antenna unit.

In one embodiment, the decoupling method may further include the following operations: defining a first length of the first decoupling transmission line as d ₃ , defining a second length of the second decoupling transmission line as d ₄ , defining a phase of isolation between the first antenna unit and the second antenna unit when the first decoupling network and the second decoupling network are not connected as φ ₂₁ , and these parameters satisfy the relationship defined by the above formula (23).

It is easy to understand that the relevant contents described in the decoupling principle part of this application are all applicable to the decoupling method, and will not be repeated here.

In some embodiments, the electronic device of the present application may be a mobile phone 100a as shown in FIG. 7 , and the mobile phone 100a includes but is not limited to the following structures: a housing 41 and a display screen assembly 50 connected to the housing 41. A housing space is formed between the housing 41 and the display screen assembly 50. Other electronic components of the mobile phone, such as a motherboard, a battery, and an antenna device 60, are arranged in the housing space.

Specifically, the housing 41 can be made of plastic, glass, ceramic, fiber composite material, metal (e.g., stainless steel, aluminum, etc.) or other suitable materials. The housing 41 shown in FIG. 7 is generally a rectangle with rounded corners. Of course, the housing 41 can also have other shapes, such as a circle, an oblong, and an ellipse.

The display screen assembly 50 includes a display screen cover plate 51 and a display module 52. The display module 52 is attached to the inner surface of the display screen cover plate 51. The housing 41 is connected to the display screen cover plate 51 of the display screen assembly 50. The display screen cover plate 51 may be made of glass; the display module 52 may be an OLED flexible display screen structure, which may specifically include a substrate, a display panel (Panel), and an auxiliary material layer, etc. In addition, a polarizing film or other structure may be sandwiched between the display module 52 and the display screen cover plate 51. The detailed stacking structure of the display module 52 is not limited here.

The antenna device 60 may be completely accommodated in the housing 41 , or may be embedded in the housing 41 , and a portion of the antenna device 60 may be exposed on the outer surface of the housing 41 .

The antenna device 60 may include a plurality of antenna units. For example, the antenna module 60 shown in FIGS. 8 to 12 is a four-element linear array, that is, it has four antenna units 10a, 20a, 10b and 20b arranged along a straight line. Specifically, in conjunction with FIG. 12 , the antenna device 60 includes a first substrate 61, a second substrate 62, a third substrate 63 and a radio frequency chip 64 stacked in sequence, and a plurality of antenna units formed on the first substrate 61 (FIG. 12 only shows two antenna units 10a, 20a), a plurality of metal layers 661-668 formed on the first substrate 61 and the third substrate 63 (wherein the metal layer 665 is a ground layer 665), a feeder passing through the third substrate 63 and the second substrate 62, and a first decoupling network 31 and a second decoupling network 31' arranged on the third substrate 63, and a first decoupling transmission line 33 and a second decoupling transmission line 34 connected therebetween. Among them, the feeder lines correspond to the antenna units 10a and 20a one by one, and are respectively used to connect the corresponding antenna units 10a and 20a to the RF chip 64. The first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween are used to connect the feeders corresponding to the adjacent antenna units 10a and 20a together to offset the coupling between the antenna units 10a and 20a. The first decoupling transmission line 33 and the second decoupling transmission line 34 may both be in the same plane layer, for example, arranged in the third substrate 63; in addition, the first decoupling transmission line 33 and the second decoupling transmission line 34 may be arranged in a bent shape to meet the length design. It can be grounded, and the antenna device 60 may also include other signal transmission lines.

The antenna units 10a and 20a are used to transmit and receive radio frequency signals. As shown in FIG12 , the two antenna units 10a and 20a are spaced apart from each other. The antenna units 10a and 20a are double-layer patch antennas, including surface radiation plates 11a and 21a and inner radiation plates 12a and 22a that are isolated from each other and correspond to each other one by one.

The first substrate 61 includes a first outer surface 611 and a first inner surface 612 that are arranged opposite to each other. The surface radiation sheets 11a and 21a are arranged on the first outer surface 611, and the inner radiation sheets 12a and 22a are arranged on the first inner surface 612. The inner radiation sheets 12a and 22a are isolated from the surface radiation sheets 11a and 21a by the first substrate 61, so that a certain distance is spaced between the surface radiation sheets 11a and 21a and the inner radiation sheets 12a and 22a, thereby meeting the performance requirements of the antenna frequency band. The vertical projections of the surface radiation sheets 11a and 21a and the inner radiation sheets 12a and 22a on the first substrate 61 at least partially overlap.

The first substrate 61 may be made of a thermosetting resin such as an epoxy resin, a thermoplastic resin such as a polyimide resin, a reinforcing material including glass fiber (or glass cloth, or glass fabric) and/or an inorganic filler, and an insulating material of a thermosetting resin and a thermoplastic resin (e.g., a prepreg, ABF (Ajinomoto Build-up Film), a photosensitive dielectric (PID), etc.). However, the material of the first substrate 61 is not limited thereto. That is, a glass plate or a ceramic plate may also be used as the material of the first substrate 61. Alternatively, a liquid crystal polymer (LCP) having a low dielectric loss may also be used as the material of the first substrate 61 to reduce signal loss.

In some embodiments, the first substrate 61 may be a prepreg. As shown in FIG. 12 , the first substrate 61 includes three layers of stacked prepregs. Among the three layers of prepregs of the first substrate 61, metal layers 662 and 663 are respectively provided between adjacent prepregs. A metal layer 661 is also provided on the first outer surface of the first substrate 61. The metal layer 661 and the surface radiation sheets 11a and 21a are located on the same layer and are insulated from each other. A metal layer 664 is provided on the first inner surface 612 of the first substrate 61. The metal layer 664 and the inner radiation sheets 12a and 22a are located on the same layer and are insulated from each other. The metal layers 661, 662, 663 and 664 may be made of conductive materials such as copper, aluminum, silver, tin, gold, nickel, lead, titanium or alloys thereof. In this embodiment, the metal layers 661, 662, 663 and 664 are all copper layers.

The provision of the metal layer 661 reduces the difference between the copper coverage rate of the first outer surface 611 of the first substrate 61 and the copper coverage rate of the surfaces of other prepregs of the first substrate 61. During the manufacturing process of the first substrate 61, the reduction in the difference in the copper coverage rate can reduce the generation of bubbles, thereby improving the manufacturing yield of the first substrate 61. Similarly, the provision of the metal layer 664 also reduces the difference between the copper coverage rate of the first inner surface 612 of the first substrate 61 and the copper coverage rate of the surfaces of other prepregs of the first substrate 61, thereby reducing the generation of bubbles during the manufacturing process of the first substrate 61, thereby improving the manufacturing yield of the first substrate 61.

The first substrate 61 is also provided with a grounding via 613 that penetrates the first inner surface 612 and the first outer surface 611, so that different metal layers 661, 662, 663 and 664 are connected to each other and further connected to the grounding layer 665. Specifically, the grounding via 613 can be completely filled with a conductive material, or the conductive material can be formed into a conductive layer along the hole wall of the grounding via 613. The conductive material can be copper, aluminum, silver, tin, gold, nickel, lead, titanium or their alloys, etc. The grounding via 613 can have a cylindrical shape, an hourglass shape or a cone shape, etc.

The second substrate 62 includes a first side surface 621 and a second side surface 622, wherein the first side surface 621 is stacked on the first inner surface 612 of the first substrate 61. The second substrate 62 may be a core layer of a PCB board, and is made of materials such as polyimide, polyethylene terephthalate, and polyethylene naphthalate. The second substrate 62 is provided with a grounding via 623 and a feeder via 624 that penetrate the first side surface 621 and the second side surface 622.

The grounding layer 665 is sandwiched between the second substrate 62 and the third substrate 63. The grounding layer 665 is provided with a feeder via hole 665a.

The third substrate 63 includes a second outer surface 631 and a second inner surface 632 opposite to each other. The second inner surface 632 of the third substrate 63 is stacked on the second side surface 622 of the second substrate 62, and the ground layer 665 is sandwiched between the second side surface 622 and the second inner surface 632.

The forming material of the third substrate 63 can be the same as that of the first substrate 61. In some embodiments, the third substrate 63 can be a prepreg. As shown in FIG12 , the third substrate 63 includes three layers of prepreg. Among the three layers of prepreg of the third substrate 63, metal layers 666 and 667 are provided between adjacent prepregs, which serve as a feed network and a control line wiring layer, respectively. A metal layer 668 is provided on the second outer surface 631 of the third substrate 63, and the metal layer 668 is welded to the RF chip 64. Among them, the metal layers 666, 667 and 668 can be made of conductive materials such as copper, aluminum, silver, tin, gold, nickel, lead, titanium or their alloys. In this embodiment, the metal layers 666, 667 and 668 are all copper layers.

The third substrate 63 is provided with wiring vias. The wiring vias include a grounding via 633, so that different metal layers 666, 667 and 668 are connected to each other and further connected to the grounding layer 665. The wiring vias also include a feeder via 634 for the feeder to pass through and a signal via 635 for the control line to pass through. Similar to the grounding via 613 on the first substrate 61, the wiring vias on the third substrate 63 can be completely filled with conductive material, or a conductive layer can be formed on the hole wall. The shapes of the various wiring vias can be cylindrical, hourglass or conical.

One end of a feeder is connected to the RF chip 64, and the other end passes through the feeder via 634 of the third substrate 63 and is connected to the first decoupling network 31. One end of another feeder is connected to the first decoupling network 31, and the other end passes through the feeder via 665a of the ground layer 665 and the feeder via 624 of the second substrate 62 and is connected to the inner radiation plates 12a and 22a to transmit signals between the antenna units 10a and 20a and the RF chip 64. Specifically, the feeder includes a first feeder 31a and a second feeder 32a connected through a decoupling network. Among them, the first feeder 31a is connected to the RF chip 64, and the second feeder 32a is connected to the inner radiation plates 12a and 22a. The feeder is insulated from each metal layer, such as the metal layers 666, 667, 668 and the ground layer of this embodiment. It is noted here that the first feeder line 31 a in FIG. 12 may be connected to the first transmission line 311 in FIG. 3 , and the second feeder line 32 a may be connected to the second transmission line 312 in FIG. 3 .

In addition, other signal transmission lines, such as a control line 68 and a power line 69, are also provided on the third substrate 63. As shown in FIG12 , the power line 69 is provided on the second outer surface 631 of the third substrate 63 and is welded on the RF chip 64. The control line 68 is provided between the semi-cured sheet of the third substrate 63 close to the RF chip 64 and the semi-cured sheet adjacent thereto, and is connected to the RF chip 64 through the signal via 635 on the semi-cured layer.

In addition, the third substrate 63 is also used to carry the first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween. As shown in FIG12 , the first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween are connected between the feeders corresponding to the adjacent antennas 10a and 20a. The first decoupling network 31 is connected to the connection between the first feeder 31a and the second feeder 32a corresponding to one antenna unit 10a; specifically, the first transmission line 311 (see FIG3 ) of the first decoupling network 31 is connected to the first feeder 31a, and the second transmission line 312 of the first decoupling network 31 is connected to the second feeder 32a. Similarly, the second decoupling network 31' is connected at the connection between the first feeder 31a and the second feeder 32a corresponding to the adjacent antenna unit 20a; that is, the first transmission line 311' (see Figure 5) of the second decoupling network 31' is connected to the first feeder 31a corresponding to the antenna unit 20a, and the second transmission line 312' of the second decoupling network 31' is connected to the second feeder 32a corresponding to the antenna unit 20a.

Since the first decoupling network 31 and the second decoupling network 31' are arranged between two adjacent antenna units of the antenna device, and the first decoupling transmission line 33 and the second decoupling transmission line 34 are connected between the first decoupling network 31 and the second decoupling transmission line 34, after the signal emitted from the RF chip 64 passes through the first feeder 31a, a part of it is transmitted to the inner radiation plate 12a of the antenna unit through the first decoupling network 31 and the second feeder 32a, and the other part is transmitted to the second decoupling network 31' through the first decoupling network 31 and the first decoupling transmission line 33 and the second decoupling transmission line 34 to reach the adjacent antenna unit 20a, thereby offsetting the coupling between the two antenna units 10a, 20a to a certain extent.

The coupling degree between the two antenna units 10a and 20a can be defined by the S parameters of the first decoupling network 31 and the second decoupling network 31' and the lengths of the first decoupling transmission line 33 and the second decoupling transmission line 34. Specifically, as in the above-mentioned embodiment of the array antenna, the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 of the antenna device 60 of this embodiment, the S parameters of the first decoupling network 31, and the preset coupling degree satisfy the following relationship:

In some embodiments, the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 and the S parameters of the first decoupling network 31 may be configured to set the coupling degree D1 between the two antenna units 10a and 20a to zero.

Furthermore, in some embodiments, when the coupling degree D1 between the two antenna units 10a and 20a is set to zero, the coupling degree D of the required directional coupler is calculated based on the initial isolation S12' between the two antenna units 10a and 20a, see the aforementioned formula (22) for details.

As shown in FIG. 11 , it is a partial schematic diagram of the antenna device of FIG. 10 , which mainly shows the arrangement of the first decoupling network 31 and the second decoupling network 31 ′ and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween. In this embodiment, the first decoupling transmission line 33 and the second decoupling transmission line 34 are arranged in different bends, wherein the length d ₃ of the first decoupling transmission line 33 includes a plurality of bends, that is, d ₃ =L1*2+L2*2+L3. The length d ₄ of the second decoupling transmission line 34 includes a plurality of bends, that is, d ₄ =L4*2+L5*2+L6.

Furthermore, the sum of _d3 and _d4 is approximately equal to twice the wavelength, that is, 2*λ=2*6.45 mm=12.9 mm.

Since the second decoupling network 31' can be the same as the first decoupling network 31, the arrangement of the transmission line of the second decoupling network 31' can be the same as the bending arrangement of the transmission line in the first decoupling network 31.

In some embodiments, the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 can also be calculated according to the phase _φ21 of the isolation before decoupling, as shown in the above formula (23).

In some embodiments, according to the calculated coupling degree D of the directional coupler, the characteristic impedance of each branch of the directional coupler can be determined, that is, the characteristic impedance Z ₀ of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33 and the second decoupling transmission line 34, the characteristic impedance Z ₁ of the fifth transmission line 315 and the seventh transmission line 317, and the characteristic impedance Z ₂ of the sixth transmission line 316 and the eighth transmission line 318, see the above formulas (24) and (25) for details. Furthermore, the line width of the transmission line corresponding to the characteristic impedance can be calculated so as to manufacture the directional coupler.

As described in the above embodiment of the antenna array, the characteristic impedance of the transmission line can be made to meet the requirements by configuring the line width of the transmission line. For example, the line widths of the first transmission line 311, the second transmission line 312, the third transmission line 313, the fourth transmission line 314, the first decoupling transmission line 33, and the second decoupling transmission line 34 are configured so that their characteristic impedances meet the above characteristic impedance Z ₀ . The line widths of the fifth transmission line 315 and the seventh transmission line 317 are configured so that their characteristic impedances meet the above characteristic impedance Z ₁ . The line widths of the sixth transmission line 316 and the eighth transmission line 318 are configured so that their characteristic impedances meet the above characteristic impedance Z ₂ .

Therefore, the first decoupling network 31 and the second decoupling network 31', which have lengths satisfying the above-mentioned required lengths, and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween can be formed on the layer where the metal layer 666 is located. It can be understood that when the straight-line distance between the feed lines corresponding to the adjacent antenna units 10a and 20a is small, the first decoupling transmission line 33 and the second decoupling transmission line 34 can form a bent pattern to meet the length requirement (as shown in Figures 10 and 11). In some other embodiments, the first decoupling transmission line 33 can also be in a bent pattern as long as the length requirement is met.

The first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween are located in different layers from the surface radiation plates 11a, 21a and the inner radiation plates 12a, 22a. As shown in FIG12, the first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween are arranged below the antenna units 10a, 20a, for example, in the third substrate 63. The first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween shown in FIG12 are located in the same layer as the metal layer 666, that is, they are arranged between the semi-cured sheet closest to the ground layer 665 of the third substrate 63 and its adjacent semi-cured sheet. It can be understood that in some other embodiments, the first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween can also be in the same layer as the metal layer 667 or 668.

The above is an introduction to the two antenna units 10a and 20a, the first decoupling network 31 and the second decoupling network 31', and the first decoupling transmission line 33 and the second decoupling transmission line 34. However, it is easy to understand that, as shown in Figure 10, the decoupling structure of the present application can also be set for the antenna units 20a and 10b and the antenna units 10b and 20b. For example, the third decoupling network 35 and the fourth decoupling network 35' and the third decoupling transmission line 33' and the fourth decoupling transmission line 34' connected between the third decoupling network 35 and the fourth decoupling network 35' can be set for the antenna units 20a and 10b; the third decoupling network 35 can be the same as or similar to the first decoupling network 31 mentioned above, and the fourth decoupling network 35' can be the same as or similar to the second decoupling network 31' mentioned above; the third decoupling transmission line 33' can be the same as or similar to the first decoupling transmission line 33 mentioned above, and the fourth decoupling transmission line 34' can be the same as or similar to the second decoupling transmission line 34 mentioned above. In addition, the second decoupling network 31' and the third decoupling network 35 may share some transmission lines, for example, the first transmission line 311', the second transmission line 312' and the fifth transmission line 315' of the second decoupling network 31' (see FIG. 5 ).

When more than three antenna units are used as shown in FIG10 , these decoupling networks and decoupling transmission lines may also be distributed in different layers. For example, the first decoupling network 31 and the second decoupling network 31′ and the first decoupling transmission line 33 and the second decoupling transmission line 34 connected therebetween may be distributed in the layer where the metal layer 666 shown in FIG12 is located, while the third decoupling network 35 and the fourth decoupling network 35′ and the third decoupling transmission line 33′ and the fourth decoupling transmission line 34′ connected therebetween may be distributed in the layer where the metal layer 667 shown in FIG12 is located.

See Figure 13, which is a schematic diagram of an antenna device of another embodiment of the present application. In the antenna device 60 of this embodiment, the top portion of the middle frame 42 of the mobile phone, for example, can be divided into two sections by a gap 44, and the two sections can be used as the first antenna 10a and the second antenna 20a, respectively. A circuit board 43 can be set in the middle frame 42, and the first decoupling network 31 and the second decoupling network 31' and the first decoupling transmission line 33 and the second decoupling transmission line 34 (see Figure 3) mentioned above in the present application can be arranged on the circuit board 43. The feed source 40 and the feed source 40' can be connected to the circuit board 43, and the circuit board 43 is connected to the first antenna 10a and the second antenna 20a. The gap 44 can usually be set non-centrally, for example, close to the left or right side of the middle frame 42.

In the example of the decoupling design of the four-element linear array as shown in Figures 8 to 10 in the present application, the central operating frequency of the four-element linear array is 28 GHz. It is pointed out here that according to the provisions of the 3GPP TS 38.101 protocol, the frequencies between 24.25 GHz and 52.6 GHz are generally referred to as millimeter waves (mm Wave); therefore, the decoupling structure proposed in the present application may be a millimeter wave array antenna decoupling structure. Figure 14 shows a comparison curve of the coupling coefficients of the antenna units before and after the decoupling network is connected. It can be seen from Figure 14 that at the central operating frequency of 28 GHz: affected by the coupling effect, the coupling coefficient between the units before decoupling is -13.5 dB; after decoupling, the coupling coefficient of the antenna is reduced by 25 dB compared with that before decoupling, which significantly suppresses the coupling effect between the units.

Figure 15 shows the comparison curve of the reflection coefficient of the antenna unit before and after the decoupling network is connected. It can be seen from the figure that, affected by the coupling effect, the resonant frequency of the unit in the array before decoupling shifts from 28GHz to 29.5GHz, and the shift reaches 1.5GHz, which is a serious shift; after decoupling using the technology of the present application, the resonant frequency of the unit in the array is 28.2GHz, which is consistent with the isolated unit, significantly improving the matching characteristics of the antenna.

Figures 16 and 17 show the comparison curves of the radiation performance of the antenna device before and after the decoupling network is connected when the beam is scanned to 0°. It can be seen from the figure that the gain before decoupling is 11.40dB; affected by the coupling effect, the gain after decoupling is 11.15dB, which is reduced by 0.25dB.

Figures 18 and 19 show the comparison curves of the radiation performance of the antenna device before and after the decoupling network is connected when the beam is scanned to 45 degrees. It can be seen from the figure that the gain before decoupling is 8.70dB; affected by the coupling effect, the gain after decoupling is 10.21dB, which is improved by 1.51dB.

Figures 20 and 21 show the comparison curves of the radiation performance of the antenna device before and after the decoupling network is connected when the beam is scanned to 50°. It can be seen from the figure that the gain before decoupling is 7.47dB; affected by the coupling effect, the gain after decoupling is 9.48dB, which is improved by 2.01dB.

Figure 22 shows a curve of the radiation performance of the antenna device when the beam is scanned to 55° after the decoupling network is connected. It is pointed out here that it is impossible to scan to 55° before decoupling. As can be seen from Figure 19, affected by the coupling effect, it can be scanned to 55° after decoupling, and the gain is 8.55dB, which is 1.08dB higher than the gain of 7.47dB when pointing to 50° before decoupling. It can be seen that after the decoupling network is adopted in this application, the isolation characteristics are improved, and the mutual coupling coefficient can be reduced to below -30dB; the scanning range is improved, and the scanning angle can be extended to 55 degrees; the array gain is improved, which is 2dB higher than when scanning to 50 degrees.

In summary, the antenna device of the present application introduces the concept of a decoupling network below the antenna unit. There is no need to change the structure of the array antenna unit. It is only necessary to configure the lengths _d3 and _d4 of the first decoupling transmission line 33 and the second decoupling transmission line 34 and the S parameters of the four-port network to adjust the coupling degree D1 between the antenna units 10 and 20, thereby reducing the mutual coupling between the antenna units, expanding the scanning angle, and improving the scanning gain. In addition, the coupling degree D of the directional coupler can be calculated based on the amplitude of the isolation before decoupling, and the characteristic impedance of each branch of the directional coupler can be determined according to the formula, and then the line width of the transmission line corresponding to the characteristic impedance can be calculated to make a directional coupler. Based on this method, the isolation of a multi-antenna system can be improved.

The above description is only an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims (16)

1. An antenna device, comprising: A first antenna unit and a second antenna unit are arranged adjacent to each other; A first decoupling network, wherein the first decoupling network has an input port, an output port, a first connection port, and a second connection port; the output port is connected to the first antenna unit, and the input port is used to connect to a first feed source; a second decoupling network, wherein the second decoupling network has an input port, an output port, a first connection port, and a second connection port; the output port of the second decoupling network is connected to the second antenna unit, and the input port of the second decoupling network is used to connect to a second feed source; a first decoupling transmission line, the first decoupling transmission line connecting a first connection port of the first decoupling network and a first connection port of the second decoupling network; and a second decoupling transmission line, wherein the second decoupling transmission line connects a second connection port of the first decoupling network and a second connection port of the second decoupling network; The first decoupling network and the second decoupling network have the same scattering parameter; The first decoupling network comprises a fifth transmission line, a sixth transmission line, a seventh transmission line and an eighth transmission line connected end to end in a polygonal shape, the characteristic impedance of the fifth transmission line and the seventh transmission line is Z ₁ , the characteristic impedance of the sixth transmission line and the eighth transmission line is Z ₂ , and the characteristic impedance of the first decoupling transmission line and the second decoupling transmission line is Z ₀ ; Wherein, Z ₀ is a preset value, and Z ₁ and Z ₂ are calculated according to the following formula: Where h is the impedance transformation factor, which is calculated according to the following formula: Wherein, D is the coupling degree of the first decoupling network, and D is calculated according to the following formula: Wherein, _S'12 is the strength of the isolation when the first decoupling network and the second decoupling network are not connected between the first antenna unit and the second antenna unit; The line widths of the fifth transmission line, the sixth transmission line, the seventh transmission line, the eighth transmission line, the first decoupling transmission line, and the second decoupling transmission line are determined according to characteristic impedances Z ₀ , Z ₁ , and Z ₂ . 2. The antenna device according to claim 1, characterized in that: The coupling degree between the first antenna unit and the second antenna unit is determined according to a first length of the first decoupling transmission line, a second length of the second decoupling transmission line, and scattering parameters of the first decoupling network and the second decoupling network. 3. The antenna device according to claim 1, characterized in that: The first decoupling network and the second decoupling network are both directional couplers. 4. The antenna device according to claim 1, characterized in that: A first length of the first decoupling transmission line is defined as d ₃ , a second length of the second decoupling transmission line is defined as d ₄ , scattering parameters of the first decoupling network are defined as S ₁₂ and S ₁₃ , and a coupling degree D1 between the first antenna unit and the second antenna unit is determined according to the following relationship: Among them, e is a natural constant, j is the symbol for imaginary numbers, and k is the wave number. 5. The antenna device according to claim 1, characterized in that: The lengths of the fifth transmission line, the sixth transmission line, the seventh transmission line and the eighth transmission line are all set to (1/4)λ, where λ is the wavelength. 6. The antenna device according to claim 1, characterized in that: A sum of a first length of the first decoupling transmission line and a second length of the second decoupling transmission line is an integer multiple of a wavelength. 7. The antenna device according to claim 1, characterized in that: The first length of the first decoupling transmission line and the second length of the second decoupling transmission line are determined according to a phase of isolation when the first decoupling network and the second decoupling network are not connected between the first antenna unit and the second antenna unit. 8. The antenna device according to claim 7, characterized in that: The first length of the first decoupling transmission line is defined as d ₃ , the second length of the second decoupling transmission line is defined as d ₄ , and the phase of the isolation between the first antenna unit and the second antenna unit when the first decoupling network and the second decoupling network are not connected is defined as φ ₂₁ . These parameters satisfy the following relationship: Among them, the value corresponding to pi is π, and λ is the wavelength. 9. The antenna device according to claim 1, characterized in that: The antenna device comprises a first substrate, a second substrate and a third substrate which are stacked in sequence; The first antenna unit and the second antenna unit are formed on the first substrate; A feeder is provided inside the third substrate and the second substrate, and the feeder is connected to the first antenna unit; Another feeder is provided in the third substrate and the second substrate, and the other feeder is connected to the second antenna unit; The output port of the first decoupling network is connected to the feeder; The output port of the second decoupling network is connected to the other feeder; and The first decoupling network, the second decoupling network, the first decoupling transmission line and the second decoupling transmission line are disposed on the third substrate. 10. The antenna device according to claim 9, characterized in that: The third substrate is a multi-layer structure, and the first decoupling transmission line and the second decoupling transmission line are arranged on a layer of the third substrate. 11. The antenna device according to claim 10, characterized in that: At least one of the first decoupling transmission line and the second decoupling transmission line forms a meandering or curved pattern. 12. The antenna device according to claim 9, characterized in that: Each of the first antenna unit and the second antenna unit includes a surface radiation plate and an inner radiation plate that are isolated from each other and arranged correspondingly. The surface radiation plate is arranged on a surface of the first substrate away from the second substrate, and the inner radiation plate is arranged on a surface of the first substrate close to the second substrate. 13. The antenna device according to any one of claims 1 to 12, characterized in that it also includes: at least one third antenna unit, wherein the first antenna unit, the second antenna unit and the at least one third antenna unit are arranged in a linear array; a third decoupling network, the third decoupling network having an input port, an output port, a first connection port and a second connection port; the input port of the third decoupling network is used to connect to the second feed source, and the output port of the third decoupling network is connected to the second antenna unit; a fourth decoupling network, the fourth decoupling network having an input port, an output port, a first connection port and a second connection port; the input port of the fourth decoupling network is used to connect to a third feed source, and the output port of the fourth decoupling network is connected to the third antenna unit adjacent to the second antenna unit; a third decoupling transmission line, the third decoupling transmission line connecting the first connection port of the third decoupling network and the first connection port of the fourth decoupling network; and A fourth decoupling transmission line is connected between the second connection port of the third decoupling network and the second connection port of the fourth decoupling network. 14. The antenna device according to claim 13, characterized in that: The second decoupling network and the third decoupling network share a portion of the transmission line. 15. An electronic device, comprising: case; A display screen assembly is connected to the housing and forms a receiving space with the housing; A feed source is arranged in the accommodating space; and An antenna device is at least partially disposed in the accommodating space, and the antenna device comprises: multiple antenna elements; A plurality of decoupling networks, corresponding one to one with the plurality of antenna units, wherein each decoupling network has an input port, an output port, a first connection port and a second connection port; the output port is connected to the corresponding antenna unit, and the input port is connected to the feed source; a first decoupling transmission line connected between adjacent first connection ports of the decoupling network; and a second decoupling transmission line connected between adjacent second connection ports of the decoupling network; The plurality of decoupling networks have the same scattering parameter; Each of the decoupling networks comprises a fifth transmission line, a sixth transmission line, a seventh transmission line and an eighth transmission line connected end to end in a polygonal shape, the characteristic impedance of the fifth transmission line and the seventh transmission line is Z ₁ , the characteristic impedance of the sixth transmission line and the eighth transmission line is Z ₂ , and the characteristic impedance of the first decoupling transmission line and the second decoupling transmission line is Z ₀ ; Wherein, _Z0 is a preset value, and _Z1 and _Z2 are calculated according to the following formula: Where h is the impedance transformation factor, which is calculated according to the following formula: Wherein, D is the coupling degree of each decoupling network, and D is calculated according to the following formula: Wherein, _S'12 is the strength of the isolation when the adjacent antenna units are not connected to the corresponding decoupling networks; The line widths of the fifth transmission line, the sixth transmission line, the seventh transmission line, the eighth transmission line, the first decoupling transmission line, and the second decoupling transmission line are determined according to characteristic impedances Z ₀ , Z ₁ , and Z ₂ . 16 . The electronic device according to claim 15 , wherein the feed source comprises a plurality of feed sources, the plurality of feed sources correspond one-to-one to the plurality of decoupling networks, and each of the input ports is connected to a corresponding feed source.