CN114498017B - An easy-to-process millimeter-wave active dual-polarized antenna - Google Patents

Abstract

The invention discloses an easy-to-process millimeter wave active dual-polarized antenna, which comprises a stacked millimeter wave dual-polarized antenna, a radio frequency feed structure and a connecting structure for connecting the millimeter wave dual-polarized antenna and the radio frequency feed structure; the millimeter wave dual-polarized antenna comprises two layers of stacked metal patches and an improved double-probe gap coupling feed structure; the connecting structure comprises a solder ball for connecting the feed probe, a solder ball for structural support and an air layer brought by the height of the solder ball; the invention can effectively work in 5G millimeter wave frequency band, compared with the method that the antenna structure and the radio frequency feed structure are processed on the same multi-layer PCB (printed circuit board), the total layer number of the multi-layer PCB is reduced, the order of blind holes in the multi-layer PCB is also reduced, the processing difficulty is reduced, and finally, the processing yield of the millimeter wave dual-polarized active array antenna is improved.

Description

An easy-to-process millimeter-wave active dual-polarized antenna

Technical field

The invention relates to the electronic field and wireless communication technology, and in particular to an easy-to-process millimeter wave active dual-polarization antenna.

Background technique

Facing the system requirements of the fifth generation of wireless communications, active multi-beam array antenna systems in the millimeter wave band have received widespread attention. In addition to its small size and compact structure, millimeter-wave active array antennas also have the advantages of high gain, large bandwidth and beamforming capabilities, which can improve spectrum and energy utilization in wireless communications and provide high-speed data transmission. In addition, in order to further improve the communication capacity and quality of millimeter wave communications, the dual polarization function has almost become a necessary function of 5G millimeter wave antennas.

In order to realize the beamforming function of the array antenna, the 5G millimeter wave beamforming chip is integrated into the millimeter wave active array antenna system to provide the required amplitude and phase excitation for each unit antenna in the antenna array. Compared with early beamforming systems built from discrete components, the now popular millimeter-wave active antennas in the form of multi-layer PCBs (printed circuit boards) integrate the beamforming chip into the back of the antenna, which has the advantages of small size, Low cost, small signal loss and other advantages. However, in the implementation of millimeter-wave active dual-polarized antenna arrays, the complexity of the multi-layer PCB structure inevitably increases, and requirements such as the number of PCB layers, the order of blind holes, and the thickness-to-diameter ratio of metal holes have all reached the domestic level. The current PCB processing technology is at its limit. The scrap rate of PCB processing is high and the yield is low, which is not conducive to the popularization and application of 5G millimeter wave technology.

Contents of the invention

Technical title: The present invention provides an easy-to-process millimeter-wave active dual-polarized antenna. The active antenna structure can process the antenna structure and the radio frequency feed structure separately and then connect them together through surface mount welding, reducing the It reduces the difficulty of multi-layer PCB processing and improves the processing yield. The antenna can cover the required millimeter wave frequency band and provide reliable antenna performance.

Technical solution: An easy-to-process millimeter wave active dual-polarized antenna of the present invention includes a stacked millimeter-wave dual-polarized antenna, a radio frequency feed structure, and a connection structure connecting the millimeter wave dual-polarized antenna and the radio frequency feed structure; The millimeter-wave dual-polarized antenna consists of two stacked upper metal patches, a lower metal patch, and a dual-probe slot coupling feed structure that is vertically connected to the upper metal patch and the lower metal patch, that is, the feed probe and coupling Gap; the connection structure includes a feed pad located under the feed probe, a first solder ball connecting the feed pad and the lower RF feed structure, a second solder ball located at the edge of the antenna for structural support, and a second solder ball located at the edge of the antenna for structural support. the fixed pad on; the RF feed structure includes a multi-layer metal layer and a double quasi-coaxial transmission line vertically connected to the multi-layer metal layer. Below the double quasi-coaxial transmission line is the bottom microstrip line, and below the microstrip line It is the third solder ball, and below the third solder ball is the beam forming chip.

The millimeter-wave dual-polarized antenna adopts a multi-layer PCB structure, and multi-layer PCBs are arranged between the upper metal patch, the lower metal patch and below the lower metal patch.

The radio frequency feed structure adopts a multi-layer PCB structure, and a multi-layer PCB is arranged between the upper and lower layers of the multi-layer metal layer.

The millimeter-wave dual-polarized antenna adds a coupling gap to the traditional probe-feeding double-layer metal patch structure for feeding, so as to cooperate with the air layer structure in the connection structure to achieve more convenient antenna matching.

In the connection structure, the feed probe in the millimeter-wave dual-polarized antenna and the dual quasi-coaxial transmission line in the radio frequency feed structure are connected through a surface welding process relying on the first solder ball.

There is an air layer between the millimeter-wave dual-polarized antenna and the radio frequency feed structure.

The coupling gap is located between the upper metal patch or the lower metal patch and the feeding probe.

Beneficial effects: The antenna structure of the millimeter-wave dual-polarized antenna is improved based on the traditional probe-fed laminated patch antenna. The distance between the two layers of patches corresponds to the coupling between the two, and the ideal antenna bandwidth can be obtained by adjusting the coupling. The probe is implemented by a metallized via that penetrates the multilayer PCB. Different from the traditional probe-fed stacked patch antenna, the probe is not directly connected to the metal patch, but excites the upper and lower metal patches through a gap coupling feeding mechanism. This excitation method effectively neutralizes the reflection caused by the air layer in the connection structure mentioned above, so that the operating bandwidth of the antenna is guaranteed.

The connection structure, the solder balls connected to the feed probes and the solder balls used for structural support can all be placed on the pre-designed pads using the ball planting process. The millimeter wave dual polarized antenna mentioned above can Welding pads are designed at appropriate corresponding positions below and on the uppermost layer of the RF feed structure. The height of the solder ball will affect the height of the raised air layer below the millimeter-wave dual-polarized antenna, which in turn affects the matching of the entire antenna. It needs to be accurately considered in the antenna simulation calculation.

This active antenna structure can process the antenna structure and the RF feed structure separately and then connect them together through surface mount welding, which reduces the difficulty of multi-layer PCB processing and improves the processing yield. The antenna can cover the required millimeters wave frequency band, providing reliable antenna performance.

Description of the drawings

Figure 1 is a schematic cross-sectional view of an easy-to-process millimeter-wave active dual-polarized antenna stack provided by the present invention;

Figure 2 is a three-dimensional schematic diagram of the easy-to-process millimeter wave active dual-polarized antenna stack provided by the present invention;

Figure 3(a) is a schematic structural diagram of the connection between the upper patch of the millimeter-wave dual-polarized antenna and the feed probe, and Figure 3(b) is a schematic structural diagram of the connection between the lower patch and the feed probe;

Figure 4 is the simulation and test results of the reflection coefficient of the millimeter-wave dual-polarized antenna input port;

Figure 5 shows the main polarization and cross-polarization pattern measurement results of the millimeter-wave active dual-polarization antenna when the horizontal polarization beam points to 0° in the transmitting state;

Figure 6 shows the main polarization and cross-polarization pattern measurement results of the millimeter-wave active dual-polarization antenna when the horizontal polarization beam is pointed at 40° in the transmitting state;

The figure shows: upper metal patch 1, lower metal patch 2, feed probe 3, feed pad 4, coupling gap 5, fixed pad 6, first solder ball 7, second solder ball 8, air layer 9. Dual quasi-coaxial transmission line 10, bottom microstrip line 11, third solder ball 12, beam forming chip 13, and multi-layer metal layer 14.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Any changes made based on the technical ideas proposed by the present invention and based on the technical solutions shall fall within the scope of protection of the present invention.

Referring to Figures 1 to 3, the easy-to-process millimeter wave active dual-polarized antenna provided by the present invention includes a stacked millimeter-wave dual-polarized antenna, a radio frequency feed structure, and a connected millimeter-wave dual polarized antenna and radio frequency feed structure. The connection structure of the structure; the millimeter-wave dual-polarized antenna includes two stacked upper metal patches 1, lower metal patches 2, and dual probe slot coupling feeds vertically connected to the upper metal patches 1 and lower metal patches 2. The electrical structure is the feed probe 3; the connection structure includes a feed pad 4 located under the feed probe 3, a first solder ball 7 connecting the feed pad 4 and the lower RF feed structure, and a first solder ball 7 located on the edge of the antenna for structural support. The second solder ball 8 and the fixed pad 6 located on the second solder ball 8; the radio frequency feed structure includes a multi-layer metal layer 14 and a dual quasi-coaxial transmission line 10 vertically connected to the multi-layer metal layer 14. Below the quasi-coaxial transmission line 10 is the underlying microstrip line 11 , below the microstrip line 11 is the third solder ball 12 , and below the third solder ball 12 is the beam forming chip 13 . The RF feed structure includes RF connecting lines connecting each port of the antenna, millimeter wave beam forming chips, RF input circuits, DC power supply circuits and control circuits.

The radio frequency feed structure includes radio frequency connection lines for connecting various ports of the antenna, millimeter wave beam forming chips, radio frequency input circuits, DC power supply circuits, control circuits and other structures. The RF connection lines used to connect each port of the antenna include dual quasi-coaxial transmission lines and microstrip lines. The dual quasi-coaxial transmission lines run through the entire multi-layer PCB RF feed structure, including the central feed through hole and the surrounding The ground via hole and microstrip line are responsible for connecting the quasi-coaxial line and the RF output port of the beamforming chip. The RF input circuit, DC power supply and control circuit used to feed and power the beamforming chip are integrated in the multi-layer PCB of the RF feed structure.

The millimeter-wave dual-polarized antenna is manufactured on a 6-layer PCB. The key structures include: upper metal patch 1, lower metal patch 2 and feed probes used to excite two polarized radiation modes. Needle 3, where the signals on the feeding probe 3 are fed and excited to the upper metal patch 1 and the lower metal patch 2 through the coupling gap 5, as shown in Figure 2, Figure 3(a), Figure 3( b) shown. In addition, a feed pad 4 and a fixing pad 6 are respectively placed below the feed probe 3 and at appropriate positions around the antenna, so as to be soldered to the first solder ball 7 and the second solder ball 8 in the connection structure.

The connection structure includes a first solder ball 7 for connecting the feed probe 3 in the millimeter-wave dual-polarized antenna and the dual quasi-coaxial transmission line 10 in the radio frequency feed structure, and also includes a first solder ball 7 placed at an appropriate position around the bottom of the antenna. The second solder ball 8 is used for structural support. After calculation and testing, the second solder ball 8 has a small impact on the performance parameters of the antenna. Since the connection structure raises the antenna PCB to a certain height, the air in it Layer 9 will have a great impact on the input matching of the antenna. The slot coupling structure provided by the present invention can be used to neutralize the impact of the air layer 9 in the connection structure on the antenna matching. As shown in Figure 4, the input scattering parameters of the antenna are less than -10dB in the required millimeter wave operating frequency band, which meets the needs of use.

The RF feed structure is fabricated and processed on an 8-layer PCB, and mainly includes dual quasi-coaxial transmission lines 10 connecting the antenna port and the output port of the beam forming chip, the bottom microstrip line 11, the third solder ball 12, millimeter wave multi-layer The channel radio frequency transceiver beam forming chip 13, radio frequency input circuit, DC power supply circuit, control and other other circuits and other structures. Among them, the dual quasi-coaxial transmission line 10 running through the multi-layer PCB and the bottom microstrip line 11 are designed to have an impedance of 50 ohms consistent with the port of the beam forming chip 13 to ensure good connection performance. The radio frequency input circuit, control circuit, power supply circuit and other structures connected to the input port of the beam forming chip 13 are integrated in the multi-layer metal layer 14 and have no special features, which will not be described again here.

In order to verify the authenticity and reliability of the easy-to-process millimeter-wave active dual-polarized antenna provided by the present invention, an active dual-polarized array antenna operating in the 24GHz to 28GHz frequency band was produced according to this implementation case. The scale of the array is 2×4. Two 8-channel millimeter wave beam forming chips are used to excite a total of 16 channels of eight antenna units. The designed example PCBs all use Rogers 3003 sheet as the core board and Rogers 4450F sheet as the adhesive material. Figures 5 to 6 show the radiation pattern results of the horizontally polarized radiation pattern of the physical array antenna in the transmitting state. It can be seen from the experimental results that the array antenna can reach a maximum phased beam scanning angle of ±40° after calibration, and can provide high cross-polarization suppression in the direction of the beam pointing.

The above embodiments are only for illustrating the technical ideas of the present invention and cannot limit the protection scope of the present invention. Any changes made based on the technical solutions based on the technical ideas proposed by the present invention will fall within the protection scope of the present invention. Inside.

Claims (7)

1. An easy-to-process millimeter wave active dual-polarized antenna, characterized in that the antenna includes a stacked millimeter-wave dual-polarized antenna, a radio frequency feed structure, and a connection between the millimeter wave dual-polarized antenna and the radio frequency feed structure. Connection structure; the millimeter-wave dual-polarized antenna includes two layers of stacked upper metal patches (1) and lower metal patches (2), and vertically connected to the upper metal patches (1) and lower metal patches (2). The dual-probe gap coupling feed structure is the feed probe (3) and the coupling gap (5); the connection structure includes the feed pad (4) located under the feed probe (3) and the connecting feed pad (4) and the first solder ball (7) of the lower RF feed structure, the second solder ball (8) located at the edge of the antenna for structural support, and the fixed pad (6) located on the second solder ball (8); the RF feed The electrical structure includes a multi-layer metal layer (14) and a double quasi-coaxial transmission line (10) vertically connected to the multi-layer metal layer (14). Below the double quasi-coaxial transmission line (10) is a bottom microstrip line (11) ), below the microstrip line (11) is the third solder ball (12), and below the third solder ball (12) is the beam forming chip (13); the double quasi-coaxial transmission line runs through the entire multi-layer PCB radio frequency feed structure, Contains a central feed via and surrounding ground vias. 2. The easy-to-process millimeter-wave active dual-polarized antenna as claimed in claim 1, characterized in that the millimeter-wave dual-polarized antenna adopts a multi-layer PCB structure, with a metal patch (1) on the upper layer. , multi-layer PCBs are provided between the lower metal patches (2) and below the lower metal patches (2). 3. The easy-to-process millimeter-wave active dual-polarized antenna according to claim 1, characterized in that the radio frequency feed structure adopts a multi-layer PCB structure, and is formed on the multi-layer metal layer (14). , there is a multi-layer PCB between the lower two layers. 4. The easy-to-process millimeter-wave active dual-polarized antenna according to claim 1, characterized in that the millimeter-wave dual-polarized antenna is added to the structure of a traditional probe-fed double-layer metal patch. The coupling gap (5) is used for feeding to cooperate with the air layer (9) in the connection structure to achieve more convenient antenna matching. 5. The easy-to-process millimeter-wave active dual-polarized antenna according to claim 1, characterized in that in the connection structure, the feed probe (3) and the radio frequency feed in the millimeter-wave dual-polarized antenna The dual quasi-coaxial transmission lines (10) in the structure rely on the first solder ball (7) and are connected through surface welding. 6. The easy-to-process millimeter-wave active dual-polarized antenna according to claim 1, characterized in that an air layer (9) is provided between the millimeter-wave dual-polarized antenna and the radio frequency feed structure. 7. The easy-to-process millimeter wave active dual-polarized antenna according to claim 4, characterized in that the coupling gap (5) is located between the upper metal patch (1) or the lower metal patch (2) and the feed between the electrical probes (3).