CN119994423B - Tunable cavity filter coupler, antenna device and communication equipment - Google Patents

Abstract

The embodiment of the application provides a tunable cavity filter coupler, an antenna device and communication equipment, and relates to the technical field of mobile communication. The tunable cavity filter coupler comprises a dielectric substrate, a base layer and a metal layer arranged on at least one side surface of the base layer, wherein the metal layer is provided with an annular coupler and a bias circuit, the annular coupler comprises four center loading branch resonators distributed in sequence along the circumferential direction, each center loading branch resonator is connected with a varactor diode, the metal layer further comprises feed ports which are in one-to-one correspondence with the center loading branch resonators and are connected with the center loading branch resonators, and the bias circuit is arranged on the periphery of the annular coupler in a surrounding mode and is electrically connected with the varactors. The tunable cavity filter coupler, the antenna device and the communication equipment provided by the application realize the frequency selectivity and the passband tunable function and meet the multi-band operation requirement.

Description

Tunable cavity filter coupler, antenna device and communication equipment

Technical Field

The present application relates to the field of mobile communications technologies, and in particular, to a tunable cavity filter coupler, an antenna device, and a communications device.

Background

The filtering Rat-Race coupler is a directional coupler, and an internal transmission path of the directional coupler is in a ring structure, so that a specific phase difference and power distribution are generated in the transmission process of signals.

However, most of the conventional filter Rat-Race couplers have the problem of fixed response of the filter coupler, and the design lacks the reconfigurability and flexibility, so that the requirements of various functions such as different frequency bands, bandwidths, phase shifts or power distribution are difficult to meet.

Disclosure of Invention

The embodiment of the application provides a tunable cavity filter coupler, an antenna device and communication equipment, which realize the frequency selectivity and passband tunable function and meet the requirement of multi-band operation.

In a first aspect, an embodiment of the present application provides a tunable cavity filter coupler, including:

the dielectric substrate comprises a base layer and a metal layer arranged on at least one side surface of the base layer, wherein the metal layer is provided with an annular coupler and a bias circuit, the annular coupler comprises four center loading branch resonators which are distributed in sequence along the circumferential direction, each center loading branch resonator is connected with a varactor diode, and the metal layer further comprises feed ports which are in one-to-one correspondence with the center loading branch resonators and are connected with the center loading branch resonators;

The bias circuit is arranged around the periphery of the annular coupler in a surrounding mode, and is electrically connected with the varactor.

In one possible implementation, the four center-loaded dendrite resonators include a first dendrite resonator and a second dendrite resonator that are oppositely arranged along a first direction, and a third dendrite resonator and a fourth dendrite resonator that are oppositely arranged along a second direction,

Wherein the feed port connected with the first branch resonator is a non-inverting input port, the feed port connected with the second branch resonator is an inverting input port,

The third and fourth branch resonators are configured to divide the signal input from the in-phase input port into equal-amplitude in-phase divided signals and divide the signal input from the anti-phase input port into equal-amplitude anti-phase divided signals.

In one possible implementation, the feed port includes a first output port and a second output port, the first output port and the second output port being connected to a third branch resonator and a fourth branch resonator,

The first and second branch resonators are configured to divide a signal flowing from the first output port to the second output port into equal-amplitude inverted divided signals, and divide a signal flowing from the in-phase input port to the inverted input port into equal-amplitude inverted divided signals.

In one possible implementation, the four center-loading branch resonators each include a main body section and a branch section, the main body sections of the first branch resonator, the third branch resonator, and the fourth branch resonator each extend in a straight line, and the branch sections are located inside the corresponding main body sections and are vertically connected with the main body sections,

The branch sections of the second branch resonators are located outside the corresponding main body sections.

In one possible implementation, two ends of each main body section are respectively formed with bending parts parallel to the diagonal line of the square.

In one possible implementation manner, the varactor diode includes a first varactor diode, the first varactor diode is disposed at an end of the branch section away from the main section, and a current-limiting resistor and a blocking capacitor are further disposed between the first varactor diode and the bias circuit.

In one possible implementation, the varactor further includes a second varactor disposed at a free end of the bent portion of the main body segment.

In one possible implementation, the varactor includes a third varactor disposed between two of the feed ports that are circumferentially adjacent.

In one possible implementation, the varactor further includes:

The tap varactor diode is arranged at the feed port;

The grounding varactor diode is arranged at the feed port and is used for grounding;

the tap varactor and the ground varactor are connected in series, one of the tap varactor and the ground varactor is arranged along a first direction, and the other is arranged along a second direction.

In a second aspect, the present application further provides an antenna device, including a tunable cavity filter coupler in any of the possible implementations described above.

In a third aspect, the present application also provides a communication device comprising an antenna arrangement according to any one of the possible implementations described above.

According to the tunable cavity filter coupler, the antenna device and the communication equipment, the varactor diode and the bias circuit are introduced, so that the coupler has higher flexibility, can be optimized for different application scenes, and can change the response characteristic of the coupler in real time by adjusting the bias voltage, so that the coupler can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through accurate design and optimization, the coupler can realize high performance indexes such as low loss, high isolation, good phase balance and the like. Therefore, the design of the tunable cavity filter coupler solves the problem of fixed response of the filter coupler in the traditional Rat-Race coupler by introducing the varactor diode and the bias circuit, and realizes the design of high performance, reconfigurability and high flexibility of the tunable cavity filter coupler.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic structural diagram of a tunable cavity filter coupler provided by the present application;

fig. 2 is a schematic diagram of a change state of a center frequency of a tunable cavity filter coupler in a low frequency band according to the present application;

Fig. 3 is a schematic diagram illustrating a change of a center frequency of the tunable cavity filter coupler in a higher frequency band.

Reference numerals:

100-dielectric substrate, 110-base layer;

200-ring coupler, 210-center loading branch resonator, 210 a-main body section, 210 b-branch section, 210 c-bending part, 211-first branch resonator, 212-second branch resonator, 213-third branch resonator, 214-fourth branch resonator;

300-bias circuit;

400-varactors, 410-first varactors, 420-second varactors, 430-third varactors, 440-tap varactors, 450-ground varactors;

500-feed port, 510-in-phase input port, 520-reverse phase input port, 530-first output port, 540-second output port;

600-current limiting resistor;

700-blocking capacitance;

800-an external direct current source;

900-ground hole.

Specific embodiments of the present application have been shown by way of the above drawings and will be described in more detail below. The drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but rather to illustrate the inventive concepts to those skilled in the art by reference to the specific embodiments.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with aspects of the application as detailed in the accompanying claims.

The filter Rat-Race coupler is a directional coupler, and the internal transmission path of the filter Rat-Race coupler is in a ring structure, so that a specific phase difference and power distribution are generated in the transmission process of signals. Conventional filtering Rat-Race couplers typically cascade two bandpass filters with the Rat-Race coupler. However, this typically results in bulky circuitry, high additional insertion loss, and matching problems.

In particular, the conventional manner of cascading two bandpass filters to a Rat-race coupler results in bulky circuit size, increased insertion loss, and matching problems. Although the filter Rat-race coupler solves part of the problems as a multifunctional monolithic device, the prior FRC designed based on a planar plate, low temperature co-fired ceramic (LTCC) technology, a Substrate Integrated Waveguide (SIW), a circular patch resonator, a dielectric resonator, a rectangular cavity resonator and the like has the problems of fixed response of the filter coupler and lack of reconfigurability and flexibility.

On the other hand, conventional reconfigurable filter couplers may be implemented using reconfigurable filter transmission lines, but most are single band tunable. There are also implementations using a piezoelectric actuator load substrate integrated waveguide cavity resonator and a varactor load step impedance resonator. However, the reconfigurability described above is designed to replace the quarter wave transmission line of the coupler prototype with the proposed resonator, which design, while achieving a degree of reconfigurability, has limitations in terms of a number of performances. Such as poor overall performance in terms of insertion loss, return loss, port isolation, phase imbalance, etc. Some designs may sacrifice other performance metrics when implementing reconfigurable functions, such as circuit size that may be large.

As can be seen, most of the conventional filtering tat-ray couplers have the problem of fixed response of the filter coupler, and the design lacks of reconfigurability and flexibility, is difficult to adapt to the requirements of modern microwave circuits and communication systems for various functions such as different frequency bands, bandwidths, phase shifts or power distribution, and cannot meet the increasing requirements of multiband or multifunctional microwave systems.

In view of this, the application provides a tunable cavity filter coupler, an antenna device and a communication device, which have higher flexibility by introducing a varactor diode and a bias circuit, can be optimized for different application scenes, and can change the response characteristic of the coupler in real time by adjusting the bias voltage, so that the coupler can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through accurate design and optimization, the coupler can realize high performance indexes such as low loss, high isolation, good phase balance and the like. Therefore, the design of the tunable cavity filter coupler solves the problem of fixed response of the filter coupler in the traditional Rat-Race coupler by introducing the varactor diode and the bias circuit, and realizes the design of high performance, reconfigurability and high flexibility of the tunable cavity filter coupler.

A tunable cavity filter coupler according to an embodiment of the first aspect of the present application is described below with reference to fig. 1 to 3. Optionally, x is a first direction and y is a second direction.

Referring to fig. 1, the tunable cavity filter coupler of the present embodiment includes a dielectric substrate 100, and the dielectric substrate 100 is generally made of a high-performance microwave material as a basis for the entire coupler. The dielectric substrate 100 includes a base layer 110 and a metal layer disposed on at least one side surface of the base layer 110 for constructing a circuit structure.

Alternatively, the dielectric substrate 100 may be a rogers RO4003C high frequency board, which has advantages of low loss, stable dielectric constant, strong high temperature stability, and the like. In some examples, dielectric substrate 100 may have a dielectric constant of 3.55F/m, a loss tangent of 0.0027, and a thickness of 0.508cm.

The metal layer is provided with a ring coupler 200 and a bias circuit 300, wherein the ring coupler 200 includes four center-loaded stub resonators 210 sequentially distributed in the circumferential direction to achieve coupling and phase shifting of signals.

Each center-loading branch resonator 210 has a varactor diode 400 connected thereto, and it is understood that the varactor diode 400 is an electronic element having a characteristic that a capacitance varies with a voltage, and a capacitance value thereof can be changed by adjusting voltages at both ends thereof, thereby changing a resonant frequency of the resonator, so that a response of the entire coupler becomes tunable.

The metal layer further includes feed ports 500 in one-to-one correspondence and connection with the center-loaded stub resonators 210 for input and output signals, and further, better performance can be achieved by adjusting the impedance matching of the feed ends.

The bias circuit 300 is disposed around the outer circumference of the ring coupler 200 and is electrically connected to the varactor 400. It will be appreciated that the bias circuit 300 is used to provide the desired voltage to the varactor 400 to control its capacitance. Specifically, by adjusting the bias voltage, the response characteristics of the coupler can be dynamically changed.

It can be seen that by introducing the varactor 400 and the bias circuit 300, the coupler has higher flexibility, can be optimized for different application scenarios, and can change the response characteristic of the coupler in real time by adjusting the bias voltage, so that the coupler can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through accurate design and optimization, the coupler can realize high performance indexes such as low loss, high isolation, good phase balance and the like.

Thus, the design of the tunable cavity filter coupler solves the problem of fixed response of the filter coupler existing in the traditional Rat-Race coupler by introducing the varactor 400 and the bias circuit 300, and realizes the design of high performance, reconfigurability and high flexibility of the tunable cavity filter coupler.

Optionally, an external dc source 800 is further disposed on the dielectric substrate 100, and the external dc source 800 is used to connect to the bias circuit 300.

In some embodiments, in conjunction with fig. 1, the four center-loaded dendrite resonators 210 include a first dendrite resonator 211 and a second dendrite resonator 212 that are oppositely arranged along a first direction, and a third dendrite resonator 213 and a fourth dendrite resonator 214 that are oppositely arranged along a second direction, wherein the feed port 500 connected to the first dendrite resonator 211 is a non-inverting input port 510 and the feed port 500 connected to the second dendrite resonator 212 is an inverting input port 520.

The third and fourth branch resonators 213 and 214 are configured to divide the signal input from the in-phase input port 510 into equal-amplitude in-phase divided signals and the signal input from the anti-phase input port 520 into equal-amplitude anti-phase divided signals.

Optionally, the first direction and the second direction form a preset angle, and preferably, the first direction is perpendicular to the second direction.

It will be appreciated that the first and second stub resonators 211, 212 are oppositely disposed along the first direction and connected to the in-phase input port 510 and the out-of-phase input port 520, respectively, which arrangement facilitates phase control and distribution of the signals.

The third and fourth stub resonators 213 and 214 are oppositely disposed in the second direction and are configured to divide the signal input from the in-phase input port 510 into equal-amplitude in-phase divided signals and the signal input from the anti-phase input port 520 into equal-amplitude anti-phase divided signals, which enables the coupler to cope with complex signal distribution and phase relationships.

When a signal is input from the in-phase input port 510, the third and fourth branch resonators 213 and 214 divide the signal into equal-amplitude in-phase divided signals, so that the signals on the two output ports have the same amplitude and phase.

And when a signal is input from the inverting input port 520, the third and fourth branch resonators 213 and 214 divide the signal into equal amplitude inverted divided signals, so that the signals on the two output ports have the same amplitude but opposite phases.

Specifically, the two input ports are respectively a non-inverting input port 510 and an inverting input port 520, which are respectively located at two opposite positions along the first direction, and the two ports can be regarded as an "input pair" of the coupler, and correspondingly, there are also two output ports along the second direction, and the two output ports correspond to the input ports. When a signal enters from the input port, the signal passes through the coupler and finally is output from the output port.

It can be seen that by skillfully constructing the first branch resonator 211 and the second branch resonator 212 and their cooperative working relationship with the third and fourth branch resonators 214, bidirectional transmission and phase adjustment functions of signals are realized, and flexibility and reconfigurability of the tunable cavity filter coupler are improved.

In some embodiments, in conjunction with fig. 1, the feed port 500 includes a first output port 530 and a second output port 540, the first output port 530 and the second output port 540 being connected to the third branch resonator 213 and the fourth branch resonator 214, respectively.

The first or second branch resonator 211 or 212 is configured to divide a signal flowing from the first output port 530 to the second output port 540 into equal-amplitude inverted divided signals and to divide a signal flowing from the non-inverting input port 510 to the inverting input port 520 into equal-amplitude inverted divided signals.

Optionally, the signal flowing from the first output port 530 to the second output port 540 is an interference signal.

As such, taking the first output port 530 and the second output port 540 as an example, when the interference signal at the first output port 530 flows to the second output port 540, the interference signal will be distributed into the first and second branch resonators 211 and 212. It will be appreciated that the distribution of the interference signal between the first and second stub resonators 211, 212 is of equal amplitude due to the design and impedance matching of the resonators.

The first and second branch resonators 211 and 212 are designed such that the signals, when passing through them, generate a predetermined phase difference, and the phase difference generated in the signals is 180 degrees (i.e., opposite phase). The phase adjusted signal continues to flow to the second output port 540, however, since the two signals are of equal amplitude and opposite phase, they will cancel each other when superimposed at the second output port 540, resulting in an output signal that is zero or near zero.

Similarly, cancellation will also be achieved when the interfering signal at the in-phase input port 510 flows to the anti-phase input port 520, or when the interfering signal at the anti-phase input port 520 flows to the in-phase input port 510.

The design may enable reduction or elimination of interference signals, thereby enabling signal isolation between the first output port 530 and the second output port 540 and between the in-phase input port 510 and the anti-phase input port 520.

Thus, the application can realize good port matching and port isolation in various states. For example, in dual band operation, the in-band isolation between the in-phase input port 510 and the anti-phase input port 520 is better (e.g., greater than 28dB, 33dB, etc.), the return loss between the first output port 530 and the second output port 540 is better (e.g., greater than 14dB, 18dB, etc.), and good port characteristics help reduce signal reflection and crosstalk, improving performance of the communication system.

In some embodiments, in conjunction with fig. 1, four center-loading dendrite resonators 210 each include a main body section 210a and a branch section 210b, it being understood that each center-loading dendrite resonator 210 is composed of a main body section 210a and a branch section 210b, which design facilitates preset electromagnetic performance and signal processing capabilities.

The main body sections 210a of the first, third, and fourth branch resonators 211, 213, and 214 all extend straight, and the branch sections 210b are located inside the corresponding main body sections 210a and are vertically connected to the main body sections 210 a. The linear design of the three main sections 210a helps to maintain the continuity and stability of signals, and is convenient for connection with other circuit elements, while the layout design of the branch sections 210b helps to realize local regulation and fine adjustment of signals, ensure that each signal maintains an accurate phase relationship in the transmission process, and improve the performance and reliability of the whole system.

The branch section 210b of the second stub resonator 212 is located outside the corresponding body section 210 a. The design is designed to achieve a specific phase relationship or signal distribution requirement, for example, the outer layout of the branch section 210b of the signal passing through the second branch resonator 212 can effectively adjust the phase of the signal, so as to ensure that the signal is in anti-phase with the split signal generated by the first branch resonator 211.

For example, when the interference signal is transmitted to the second branch resonator 212 and the first branch resonator 211, the signal is divided into two components with equal amplitude and opposite directions, so that mutual cancellation is realized, the influence of the interference signal is effectively reduced, and the overall performance is improved. Through the layout design of the center loading branch resonator 210, not only is the efficient transmission and the accurate phase control of signals realized, but also the anti-interference capability is remarkably improved.

In addition, the synergistic effect of the branch resonators further optimizes the signal transmission efficiency and ensures stable operation in a high-frequency environment.

In some embodiments, in conjunction with fig. 1, each body segment 210a is formed with a bend 210c at each end parallel to the diagonal of the square.

This design increases the electrical length of the body section 210a, helping to tune the resonant frequency of the resonator, and in addition, the bend 210c can affect the phase response of the signal. By adjusting the position and shape of the bent portion 210c, the phase balance and phase stability of the coupler can be optimized.

Specifically, during actual operation, the parameters of the bending part 210c can be adjusted to realize accurate control of performance indexes such as resonant frequency, bandwidth, phase response and the like, so that the flexibility of the tunable cavity filter coupler is improved.

In some embodiments, in conjunction with fig. 1, the varactor 400 includes a first varactor 410, the first varactor 410 may be a branch-loaded varactor, and optionally, the first varactor 410 may be of the type SMV1413.

The first varactor 410 is disposed at an end of the branch segment 210b away from the main segment 210a, and a current-limiting resistor 600 and a blocking capacitor 700 are further disposed between the first varactor 410 and the bias circuit 300. Alternatively, the current limiting resistor 600 may have a resistance of 100 kilo-ohms. Alternatively, the capacitance value of the blocking capacitor 700 may be 100 picofarads.

The designed capacitance diode changes the capacitance value by adjusting the bias voltage, thereby precisely controlling the resonant frequency and the phase response, and further optimizing the performance of the bias circuit 300 by adjusting the parameters of the current limiting resistor 600 and the blocking capacitor 700.

Illustratively, when the first varactor 410 is tuned, the upper passband will be primarily affected, such as to make the upper passband frequency range wider, thereby improving overall band utilization.

It will be appreciated that the primary purpose of providing the current limiting resistor 600 between the first varactor 410 and the bias circuit 300 is to protect the first varactor 410 from the impact of excessive current. When the bias voltage is changed, the current limiting resistor 600 may limit the magnitude of the current passing through the first varactor 410 to prevent it from being damaged due to overheating.

The dc blocking capacitor 700 isolates the ac signal (i.e., the rf signal) from the dc bias voltage, which allows the rf signal to pass through smoothly while preventing the dc bias voltage from interfering with the rf circuit. In this way, it is ensured that the first varactor 410 can maintain its tuning function while not affecting the radio frequency performance of the tunable cavity filter coupler.

Thus, by changing the bias voltage, the capacitance value of the first varactor 410 can be changed, so as to adjust the resonant frequency of the coupler, and the tuning function can enable the tunable cavity filter coupler to adapt to different frequency bands and bandwidth requirements. In addition, the design of the current limiting resistor 600 and the blocking capacitor 700 protects the first varactor 410 from damage, and also ensures that the radio frequency performance of the tunable cavity filter coupler is not interfered by the dc bias voltage.

In some examples, the dc voltage first passes through the current limiting resistor 600 and then is grounded through a reverse varactor 400, and a blocking capacitor 700 is further disposed on one side of the varactor 400 to prevent the dc signal from entering the bias circuit 300.

The varactor 400 can be equivalently an adjustable capacitor when operating in a reverse breakdown region, and can change the equivalent capacitor by changing the bias voltage based on the principle when the bias voltage is increased and the equivalent capacitor is decreased, thereby changing the electrical structure of the whole circuit.

In some embodiments, in conjunction with fig. 1, the varactor 400 further includes a second varactor 420, and the second varactor 420 may be a two-terminal loaded varactor. Alternatively, the second varactor 420 may be of the type SMV1237.

The second varactor 420 is disposed at the free end of the bent portion 210c of the main body segment 210 a. This layout design enables the second varactor 420 to directly affect the electromagnetic performance of the body segment 210a, thereby further adjusting the resonant frequency and phase response of the coupler. By precisely adjusting the bias voltage of the second varactor 420, finer resonant frequency and phase control can be achieved.

Illustratively, when the second varactor 420 is tuned, there is a large impact on both the upper and lower pass bands, thereby optimizing overall band performance.

By introducing a second varactor 420, the tuning capability of the coupler is further enhanced, and finer control of the tunable cavity filter coupler resonant frequency and phase response can be achieved by adjusting the capacitance values of the first varactor 410 and the second varactor 420 simultaneously.

Optionally, similar to the first varactor 410, the second varactor 420 is also provided with a current-limiting resistor 600 and a blocking capacitor 700 between the bias circuit 300, so as to protect the second varactor 420 from damage, and also ensure that the radio frequency performance of the tunable cavity filter coupler is not interfered by the dc bias voltage.

In some embodiments, in conjunction with fig. 1, the varactor 400 includes a third varactor 430, the third varactor 430 may be a mid-load varactor, and optionally, the third varactor 430 may be of the type SMV1413.

The third varactor 430 is disposed between two feed ports 500 that are circumferentially adjacent. This layout design enables the third varactor 430 to directly affect the electromagnetic coupling between the two feed ports 500 to further tailor the performance of the coupler. By introducing the third varactor diode 430, the coupling strength between the feed ports 500 can be controlled more precisely, and in addition, the bandwidth and the frequency response of the tunable cavity filter coupler can be optimized, and fine adjustment of the operating frequency band of the tunable cavity filter coupler can be achieved by adjusting the capacitance value thereof.

Illustratively, when the third varactor 430 is tuned, the lower passband will be primarily affected, such as to make the lower passband frequency range wider, thereby improving overall band utilization.

Optionally, similar to the first varactor 410 and the second varactor 420, the third varactor 430 may also have a current-limiting resistor 600 and a blocking capacitor 700 disposed between the third varactor 430 and the bias circuit 300, thereby protecting the varactor 400 from damage and ensuring that the radio frequency performance of the tunable cavity filter coupler is not interfered by the dc bias voltage.

In some embodiments, in conjunction with FIG. 1, the varactor 400 further includes a tapped varactor 440 disposed at the feed port 500 and a grounded varactor 450 disposed at the feed port 500 for grounding.

Alternatively, the tapped varactor 440 may be of the type SMV1255. Alternatively, the model of the grounded varactor 450 may be SMV1247.

The tapped varactor 440 and the grounded varactor 450 are connected in series, one of the tapped varactor 440 and the grounded varactor 450 being disposed in a first direction and the other being disposed in a second direction.

It will be appreciated that the tapped varactor 440 may change the electromagnetic characteristics at the feed port 500 by adjusting the capacitance value, affecting the overall performance of the coupler, and the grounded varactor 450 is primarily used for grounding, and by adjusting its capacitance value, an adjustment to the ground coupling may be achieved, further affecting the performance of the tunable cavity filter coupler.

Optionally, the tapped varactor 440 and the grounded varactor 450 may be vertically arranged, which improves the utilization rate of the installation space, improves the compactness, and reduces electromagnetic interference between the two, thereby ensuring stable performance of the tunable cavity filter coupler.

It can be seen that the synergy of the tapped varactor 440 and the grounded varactor 450 allows the two to work together on the feed port 500, enabling independent adjustment of the external coupling of the upper passband or the lower passband.

In the above, by reasonably designing the first varactor 410, the second varactor 420, the third varactor 430, the tap varactor 440, and the ground varactor 450, independent adjustability of the upper passband and the lower passband is achieved.

In some examples, fig. 2 and fig. 3 are combined, fig. 2 is a schematic diagram showing a change state of a center frequency of a low frequency band in the present application, and fig. 3 is a schematic diagram showing a change state of a center frequency of a higher frequency band in the present application. Where S11 is the return loss of the filter coupler, and S21 and S31 are the insertion loss.

It can be seen that the present application realizes that the center frequency of the low frequency band can be varied in the range of 0.3-0.5GHz, the center frequency of the higher frequency band can be varied in the range of 0.82-1.04GHz, and that during tuning, the two frequency bands can be independently tuned, as with reference to fig. 2, the lower passband can be tuned in the range of 0.3-0.5GHz, and the upper passband can be tuned in the range of 0.82-1.04 GHz.

Optionally, the dielectric substrate 100 is further provided with a grounding hole 900 to achieve grounding and improve the safety factor.

In addition, an embodiment of the second aspect of the present application further provides an antenna apparatus, including the tunable cavity filter coupler in any one of the above embodiments.

An embodiment of the third aspect of the present application further provides a communication device, including the antenna apparatus in the above embodiment.

According to the antenna device and the communication equipment provided by the application, the tunable cavity filter coupler is arranged, and the varactor 400 and the bias circuit 300 are introduced, so that the coupler has higher flexibility, can be optimized for different application scenes, and can change the response characteristic of the coupler in real time by adjusting the bias voltage, so that the coupler can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through accurate design and optimization, the coupler can realize high performance indexes such as low loss, high isolation, good phase balance and the like. Thus, by introducing the varactor diode 400 and the bias circuit 300, the problem of fixed response of the filter coupler existing in the conventional Rat-Race coupler is solved, and the high-performance, reconfigurable and high-flexibility design of the antenna device and the communication equipment is realized.

The present application can obtain good port matching and port isolation in multiple states, for example, in-band isolation between the in-phase input port 520 and the anti-phase input port 520 is better (e.g., greater than 28dB, 33dB, etc.), return loss between the first output port 530 and the second output port 540 is better (e.g., greater than 14dB, 18dB, etc.), and compared with the prior art, good port characteristics help to reduce signal reflection and crosstalk, and improve performance of the communication system.

In addition, a plurality of transmission zeros are distributed between the two pass bands and outside the pass bands, resulting in high frequency selectivity. Compared with some filter couplers with poor frequency selectivity in the prior art, the high frequency selectivity is beneficial to better filtering out unwanted frequency components and improving the purity and communication quality of signals.

Therefore, the application realizes good reconfigurable filtering power distribution response, has the advantages of flexible and adjustable center frequency, good phase and amplitude characteristics, high in-band isolation, and the like, can be expanded to other multi-mode or multi-frequency conditions, and is expected to be widely applied in the field of mobile communication.

It should be noted that, in the foregoing description, for example, the board model of the dielectric substrate 100, the model of each varactor 400, and the like are all implementation examples, and may be replaced by other models, but it should be noted that in actual operation, after the board model or each varactor 400 model is replaced, structural parameters of each device need to be adjusted again to meet the required tuning range and application requirements.

Finally, it should be noted that other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any adaptations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the precise construction hereinbefore set forth and shown in the drawings and as follows in the scope of the appended claims. The scope of the invention is limited only by the appended claims.

Claims (11)

1. A tunable cavity filter coupler, comprising:

The dielectric substrate (100) comprises a base layer (110) and a metal layer arranged on the surface of at least one side of the base layer (110), wherein the metal layer is provided with an annular coupler (200) and a bias circuit (300), the annular coupler (200) comprises four center loading branch resonators (210) which are distributed in sequence along the circumferential direction, each center loading branch resonator (210) is connected with a varactor diode (400), and the metal layer further comprises feed ports (500) which are in one-to-one correspondence with the center loading branch resonators (210) and are connected with each other;

The bias circuit (300) is arranged around the periphery of the annular coupler (200), and the bias circuit (300) is electrically connected with the varactor diode (400).

2. The tunable cavity filter coupler of claim 1, wherein four of the center-loaded stub resonators (210) include a first stub resonator (211) and a second stub resonator (212) disposed opposite in a first direction, and a third stub resonator (213) and a fourth stub resonator (214) disposed opposite in a second direction, the first direction being perpendicular to the second direction,

Wherein the feed port (500) connected to the first branch resonator (211) is a non-inverting input port (510), the feed port (500) connected to the second branch resonator (212) is an inverting input port (520),

The third branch resonator (213) and the fourth branch resonator (214) are configured to divide a signal input from the in-phase input port (510) into equal-amplitude in-phase divided signals, and to divide a signal input from the anti-phase input port (520) into equal-amplitude anti-phase divided signals.

3. The tunable cavity filter coupler of claim 2, wherein the feed port (500) comprises a first output port (530) and a second output port (540), the first output port (530) and the second output port (540) being connected to a third branch resonator (213) and a fourth branch resonator (214), respectively,

The first (211) and second (212) branch resonators are configured to split a signal flowing from the first output port (530) to the second output port (540) into equal amplitude inverted split signals and to split a signal flowing from the in-phase input port (510) to the inverted input port (520) into equal amplitude inverted split signals.

4. The tunable cavity filter coupler of claim 2, wherein four of the center-loaded branch resonators (210) each comprise a main section (210 a) and a branch section (210 b), the first branch resonator (211), the third branch resonator (213), and the main section (210 a) of the fourth branch resonator (214) each extend in a straight line, and the branch sections (210 b) are located inside the corresponding main sections (210 a) and are connected perpendicularly to the main sections (210 a),

The branch section (210 b) of the second branch resonator (212) is located outside the corresponding main body section (210 a), and the main body section (210 a) of the second branch resonator (212) has a vertical connection portion and a parallel portion with the corresponding branch section (210 b).

5. The tunable cavity filter coupler according to claim 4, wherein the first branch resonator (211), the third branch resonator (213), and the fourth branch resonator (214) are formed with bent portions (210 c) parallel to a diagonal of a square at both ends of the main body section (210 a), respectively, the main body section (210 a) of the second branch resonator (212) is formed with bent portions (210 c) parallel to a diagonal of a square at one end, and the branch section (210 b) of the second branch resonator (212) is formed with bent portions (210 c) parallel to a diagonal of a square at one end.

6. The tunable cavity filter coupler of claim 5, wherein the varactor diode (400) comprises a first varactor diode (410), the first varactor diode (410) is disposed at an end of the branch section (210 b) away from the main section (210 a), and a current limiting resistor (600) and a blocking capacitor (700) are further disposed between the first varactor diode (410) and the bias circuit (300).

7. The tunable cavity filter coupler of claim 6, wherein the varactor diode (400) further comprises a second varactor diode (420), the second varactor diode (420) being provided at a free end of the bent portion of the body segment (210 a).

8. The tunable cavity filter coupler of claim 6, wherein the varactor diode (400) comprises a third varactor diode (430), the third varactor diode (430) being disposed between two circumferentially adjacent feed ports (500) to directly affect electromagnetic coupling between the two feed ports (500).

9. The tunable cavity filter coupler of claim 8, wherein the varactor diode (400) further comprises:

a tapped varactor (440) disposed at the feed port (500);

A grounded varactor (450) disposed at the feed port (500) and configured to be grounded;

-the tapped varactor (440) and the grounded varactor (450) are connected in series, one of the tapped varactor (440) and the grounded varactor (450) being arranged in a first direction and the other being arranged in a second direction;

the tapped varactor (440) changes the electromagnetic characteristics at the feed port (500) by adjusting a capacitance value, and the grounded varactor (450) adjusts the capacitance value to achieve adjustment of the ground coupling.

10. An antenna arrangement comprising a tunable cavity filter coupler according to any one of claims 1-9.

11. A communication device comprising the antenna arrangement of claim 10.