Millimeter-wave broadband high-gain low-cross-polarization cavity-backed patch array antenna

Abstract

The invention discloses a millimeter-wave broadband high-gain low-cross polarization cavity-backed patch array antenna, which comprises a top antenna layer, a substrate integrated waveguide (SIW) cavity power divider layer and a bottom broadband feed network layer, and is characterized in that the top antenna layer is composed of a plurality of cavity-backed patch antenna units; each unit comprises an SIW dielectric back cavity and a patch antenna with two small grooves on the edge, a broken groove is added in the middle of the patch antenna to form two split small patch structures, and the patch antenna is grounded through two metal through holes. The SIW cavity power divider layer is composed of a plurality of broadband power dividers and serves as a transition structure of the antenna layer and the feed network layer, and array antenna layout is facilitated. The bottom broadband feed network layer is composed of a plurality of H-shaped sections, is a sixteen-path power divider, is cascaded with an SIW cavity power divider, and feeds the top array antenna. The array antenna structure has a broadband characteristic and a high gain characteristic, inhibits a cross polarization component, and realizes a low cross polarization characteristic.

Description

Technical Field

[0001] The present invention relates to the field of 5G / Beyond millimeter-wave communication, and particularly to a millimeter-wave broadband high-gain low-cross-polarization back-cavity patch array antenna. Background Art

[0002] With the in-depth commercial deployment of millimeter-wave 5G / Beyond wireless communication systems and subsequent evolution research, antenna and array antenna technologies have gradually become one of the core technologies in the field of wireless communication. Due to the more significant electromagnetic attenuation in the millimeter-wave band compared to the microwave band, the role of millimeter-wave array antennas has gradually become prominent. By adopting large-scale array antenna technology, signals can be concentrated and transmitted to target customers, reducing path interference, and thus significantly improving the spectrum utilization rate. Such large-scale array antennas also have the characteristic of high gain, which can significantly expand the coverage range of base stations without increasing the transmitter power. The broadband antenna technology can support the wireless communication network's ability to handle aspects such as large data transmission, trajectory tracking, environmental perception, and positioning. The polarization purity of the antenna also affects system reliability, signal quality, channel capacity, and anti-interference characteristics. Therefore, the system's demand for array antennas with key indicators such as high gain, large bandwidth, and low cross-polarization is becoming increasingly urgent.

[0003] Millimeter-wave array antennas face a series of challenges in actual design, including complex structure, narrow bandwidth, low gain, high loss, and low cross-polarization performance. Some inefficient antenna element structures are not only difficult to feed, but also lead to a complex and inefficient feed network, making it difficult to form large-scale arrays. The antenna elements in the disclosed patent documents have a wide bandwidth, but the bandwidth of the array antenna formed becomes narrow, and the gain is also limited. In addition, due to the differences in the radiation structure, excitation method, and matching circuit of the antenna elements, there are strong coupling paths between most array antenna elements, reducing the overall radiation efficiency of the array antenna. In many documents and disclosed patents, insufficient consideration is given to the cross-polarization characteristics, which in turn affects the communication quality of the entire communication system.

[0004] To solve one of the problems existing in the current prior art, the present invention provides a novel low-profile broadband high-gain low-cross-polarization back-cavity microstrip patch antenna element and array antenna. It has the advantages of simple structure, low cost, easy to manufacture, wide bandwidth, high gain, and good cross-polarization performance, and is convenient for integrated design with planar active circuits. Summary of the Invention

[0005] 1. Technical problems to be solved: Millimeter-wave array antennas face a series of challenges, including complex structure, narrow bandwidth, low gain, high loss, and low cross-polarization performance.

[0006] 2. Technical solutions: To solve the above problems, the present invention provides a millimeter-wave broadband high-gain low-cross-polarization back cavity patch array antenna, which is an 8×8 array antenna and includes 16 2×2 antenna sub-arrays. Each 2×2 antenna sub-array includes 4 SIW back cavity patch antenna units, which include three layers of dielectric substrates and four layers of metal layers. Starting from the first metal layer, they are stacked in an alternating arrangement of metal layers and dielectric substrates from top to bottom until the fourth metal layer. All metal layers are connected by vertically penetrating metal vias to maintain a DC conduction path state. 64 SIW back cavity patch antenna units are printed on the first metal layer. Each SIW back cavity patch antenna unit includes 1 grid and a microstrip patch antenna arranged within the grid. The grid is composed of multiple metal lines arranged in a horizontal and vertical staggered pattern, and 64 grids are formed between the metal lines. Each microstrip patch antenna is provided with a patch slot, which divides the patch antenna into two small patches; a plurality of regularly arranged metallized vias are provided in the first dielectric substrate, and all the metallized vias are connected to the metal lines of the first metal layer and vertically penetrate to the second metal layer to form a rectangular SIW dielectric cavity around the grid; regular top feed slots are etched below the second metal layer and above the second dielectric substrate, and regular bottom feed slots are etched above the third metal layer and below the second dielectric substrate. The top feed slots are located directly below and parallel to the patch slot.

[0007] 16 SIW dielectric cavity power dividers are formed in the second dielectric substrate by using metallized vias and are connected to the second metal layer and the third metal layer. Each SIW dielectric cavity power divider corresponds to a 2×2 antenna sub-array; in the third dielectric substrate, the metallized vias are connected to the third metal layer and the fourth metal layer to form a sixteen-way SIW broadband power distribution feeder network.

[0008] The three layers of dielectric substrates are stacked together to establish a coordinate system. In the rectangular coordinate system, the x-axis and the y-axis are respectively parallel to two rectangular sides of the PCB board, and the z-axis points to the maximum radiation direction of the array antenna. The ports of the sixteen-way SIW broadband power distribution feeder network are parallel to the y direction, the long sides of the 16 four-way rectangular SIW dielectric cavity power dividers are parallel to the x direction, and the long sides of all feed slots are parallel to the x direction.

[0009] A groove 1-6 is provided at the middle position of the edge of the other end of each small patch away from the patch slot.

[0010] A driving via is provided at the middle position of each small patch, and the driving via connects the small patch and the second metal layer to form a DC conduction path state.

[0011] Two rows of metallized vias and six metallized matching vias are provided inside each SIW dielectric cavity, and the matching vias are used to adjust the electromagnetic energy distribution inside the dielectric cavity.

[0012] The first matching through-hole is located at both ends of the bottom feeding slot and is used to adjust the matching of the bottom feeding slot. The second matching through-hole is located at both ends of the through-hole array and is used to adjust the matching of the top feeding slot.

[0013] The sixteen-way SIW broadband power divider feeding network includes a large H-shaped section in parallel with four small H-shaped sections. Four bottom feeding slots are etched on the third metal layer at the end of each small H-shaped section. SIW through-holes connect the third metal layer and the fourth metal layer. Each of the small H-shaped sections includes an inductive matching through-hole 3-2 and an SIW transmission line 3-3.

[0014] An SIW transmission line is arranged in the third dielectric substrate 3. The port is connected to other millimeter-wave radio frequency systems through the SIW transmission line or connected to an antenna test device through an adapter structure.

[0015] The dielectric constants of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all 2.2, and the tangent of the loss angle is 0.0009. The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate adopt Taconic TLY5, with a dielectric constant of 2.2, a tangent of the loss angle of 0.0009, and a thickness of 1.016 mm.

[0016] 3. Beneficial effects: The back cavity patch antenna unit of the present invention uses slot coupling feeding, and can utilize the resonant working mode of the small patch structure, the high-order mode resonance working mode of the SIW back cavity, and the coupling slot working mode. The working bandwidth is very wide. The feeding network composed of the four-way SIW cavity power divider and the sixteen-way H-shaped section also has a very wide working bandwidth. Therefore, the entire array antenna realizes the broadband characteristic.

[0017] There is a patch break slot in the middle of the microstrip patch antenna. Patch driving through-holes are added on both sides of the patch break slot and the rectangular slot, thereby suppressing the cross-polarization component of the electromagnetic wave on the coupling slot and the small patch structure, and realizing the low cross-polarization characteristic.

[0018] The patch break slot structure in the middle of the back cavity patch antenna unit can enable two small patches and the rectangular slot below to work together. The high-order mode field distribution of the rectangular SIW back cavity is similar to the patch mode field distribution. This structural design effectively improves the gain characteristics of the unit and the array antenna.

[0019] A one-to-four SIW dielectric cavity power divider and four back cavity patch units can form a 2×2 back cavity slot patch sub-array. This design scheme can solve the problem that the feeding network of the SIW broadband power divider cannot be directly connected to the back cavity patch antenna unit through the rectangular slot. Description of the drawings

[0020] Figure 13D schematic diagram of a millimeter-wave broadband high-gain low cross-polarization back cavity patch array antenna provided by an embodiment of the present invention.

[0021] Figure 2 Top view of the top layer of the back cavity patch antenna element provided by an embodiment of the present invention.

[0022] Figure 3 Top view of a rectangular SIW dielectric cavity power divider for feeding a 2×2 sub-array provided by an embodiment of the present invention.

[0023] Figure 4 Top view of the H-shaped section that constitutes a sixteen-way SIW broadband feeding network provided by an embodiment of the present invention.

[0024] Figure 5 Schematic diagram of a 2×2 antenna sub-array provided by an embodiment of the present invention.

[0025] Figure 6 Top view of the top layer of an 8×8 back cavity patch array antenna provided by an embodiment of the present invention.

[0026] Figure 7 Reflection coefficients of the back cavity patch antenna element, 2×2 sub-array, and 8×8 array antenna provided by an embodiment of the present invention; Figure 8 Gain curves of the back cavity patch antenna element, 2×2 sub-array, and 8×8 array antenna provided by an embodiment of the present invention; Figure 9 E-plane and H-plane co-polarization and cross-polarization patterns of an 8×8 back cavity patch array antenna at 27 GHz provided by an embodiment of the present invention.

[0027] Figure 10 E-plane and H-plane co-polarization and cross-polarization patterns of an 8×8 back cavity patch array antenna at 30 GHz provided by an embodiment of the present invention.

[0028] Figure 11 E-plane and H-plane co-polarization and cross-polarization patterns of an 8×8 back cavity patch array antenna at 33 GHz provided by an embodiment of the present invention.

[0029] Figure 12 E-plane and H-plane co-polarization and cross-polarization patterns of an 8×8 back cavity patch array antenna at 36 GHz provided by an embodiment of the present invention; Figure 13 Variation relationship of the cross-polarization characteristics of an 8×8 back cavity patch array antenna with frequency provided by an embodiment of the present invention.

[0030] Explanation of the reference numerals: 1. first dielectric substrate; 1-1. SIW cavity-back patch antenna unit; 1-2. top metal boundary; 1-3. first metallized through hole; 1-4. grid; 1-5. small patch; 1-6. small groove at the edge of the patch; 1-7. patch drive through hole; 1-8. patch broken groove; 2. second dielectric substrate; 2-1. SIW dielectric cavity power divider; 2-2. second metallized through hole; 2-3. SIW dielectric cavity; 2-4. bottom feeding slot; 2-5. first matching through hole; 2-6. second matching through hole; 2-7 top feeding slot; 2-8. through hole array; 3. third dielectric substrate; 3-1. H-section; 3-2. inductive matching through hole; 3-3. SIW transmission line. DETAILED DESCRIPTION

[0031] In order to clearly illustrate the advantages of the embodiments and technical solutions of the present invention, the technical solutions therein are further described in detail below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0032] like Figure 1 As shown, a millimeter-wave broadband high-gain low cross-polarization back-cavity patch array antenna, each 2×2 antenna subarray includes 4 SIW back-cavity patch antenna units 1-1, including three layers of dielectric substrate and four layers of metal layers, starting from the first metal layer, from top to bottom, stacked in an alternating manner of metal layers and dielectric substrates until the fourth metal layer.

[0033] 64 SIW cavity-backed patch antenna units 1-1 are printed on the first metal layer. Figure 2 As shown, each of the SIW back cavity patch antenna units 1-1 includes a grid 1-4 and a microstrip patch antenna arranged in the grid 1-4. The grid 1-4 is composed of a plurality of metal lines arranged in a horizontal and vertical staggered manner, and 64 grids 1-4 are formed between the metal lines. Each of the microstrip patch antennas is provided with a patch slot 1-8, which divides the patch antenna into two small patches 1-5.

[0034] The first dielectric substrate 1 is used as a supporting plate, and 64 SIW back cavity patch antenna units 1-1 are printed on the top of the first dielectric substrate 1. Adjacent SIW back cavity patch antenna units 1-1 share a rectangular SIW short-circuit through-hole boundary. A grid structure is formed by staggered arrangement of multiple metal lines, and a back cavity patch antenna unit 1-1 is placed in the middle of each grid structure.

[0035] Etch the regular top feed slot 2-7 below the second metal layer and above the second dielectric substrate, and etch the regular bottom feed slot 2-4 above the third metal layer and below the second dielectric substrate. The top feed slot 2-7 is directly below and parallel to the patch slot 1-8. Form 16 SIW dielectric cavity power dividers 2-1 in the second dielectric substrate 2 using metallized vias to connect the second metal layer and the third metal layer. As Figure 3 shown, each SIW dielectric cavity power divider 2-1 corresponds to a 2×2 antenna sub-array.

[0036] The third dielectric substrate 3 serves as a support board and is located at the bottom of the array antenna, acting as a feed network for a sixteen-way SIW broadband power divider. It is composed of 1 large H-shaped section in parallel with four small H-shaped sections 3-1. As Figure 4 shown, each H-shaped section can also be regarded as a four-way SIW power divider, mainly composed of inductive matching vias 3-2 and SIW transmission lines 3-3. By reasonably adjusting the internal circuit structure and relative positions of the H-shaped sections 3-1, a feed network for a one-to-sixteen SIW broadband power divider can be realized. The interlayer electromagnetic energy transfer is achieved through the bottom feed slot 2-4 and the top feed slot 2-7.

[0037] In one embodiment, the three-layer dielectric substrates are stacked together, and a coordinate system is established as Figure 1 shown. In the rectangular coordinate system, the x-axis and y-axis are respectively parallel to two rectangular sides of the PCB board, the z-axis points to the maximum radiation direction of the array antenna. The ports of the sixteen-way SIW broadband power divider feed network are parallel to the y direction, the long sides of the 16 four-way rectangular SIW dielectric cavity power dividers 2-1 are parallel to the x direction, and the long sides of all coupling slots are parallel to the x direction. It can be seen that the polarization direction of the array antenna is parallel to the y-axis.

[0038] In one embodiment, the three-layer dielectric substrates of the present invention adopt Taconic TLY5, with a dielectric constant of 2.2 and a loss tangent of 0.0009. The thickness of each of the three-layer PCB dielectric substrates is 1.016 mm.

[0039] In one embodiment, the SIW dielectric cavity power divider 2-1 is rectangular, as Figure 2 and Figure 3As shown, it includes a top metal boundary 1-2, first metallized vias 1-3 arranged regularly in a square shape, and a grid structure 1-4 at the top surrounded by metal strips and SIW vias. The microstrip patch antenna is printed on the surface of the grid 1-4 and is divided into three parts: a microstrip patch, a patch slot 1-5, a small groove 1-6 at the patch edge, and a patch driving via 1-7. A rectangular top feed slot 2-7 is designed at the bottom of the SIW cavity patch antenna unit 1-1. This slot is parallel to the patch groove and is used to excite the high-order mode of the SIW cavity and the microstrip patch. This feed slot 2-7 is also one of the four top feed slots 2-7 at the edges of the top metal layer of the SIW dielectric cavity power divider 2-1 in the second dielectric substrate 2. Through this slot coupling method, electromagnetic energy is transmitted from the second dielectric substrate 2 to the first dielectric substrate 1 of the antenna layer to adjust the electromagnetic energy matching between the substrate layers. Combining Figure 1 with the reference coordinate system in

[0040] it can be known that the current distribution on the cavity patch antenna is along the y-axis, and the cross-polarization component is along the x-axis. Figure 3

[0041] The SIW dielectric cavity power divider 2-1 is a one-to-four power divider. As

[0042] shown, it consists of edge metallized vias 2-2 and upper and lower metal layers. A closed SIW dielectric cavity 2-3 is formed in the middle of the metal layers. Utilizing the regulation effect of the closed SIW cavity structure on the electromagnetic field, electromagnetic energy enters the SIW dielectric cavity 2-3 from the bottom feed slot 2-4 of the second dielectric substrate 2 and then reaches the four top feed slots 2-7 at the edges of the cavity located on the second dielectric substrate 2, dividing one-way electromagnetic energy into four-way.At the port of the third dielectric substrate 3, through the conversion structure of GCPW and SIW, electromagnetic energy can be fed into the 8×8 array antenna through the grounded coplanar waveguide GCPW for testing the antenna performance. When the array antenna is integrated into the millimeter-wave radio frequency system, the conversion structure can be removed to form an integrated design method of the array antenna and the millimeter-wave radio frequency front-end circuit. The 8×8 back cavity patch array antenna can be divided into a top antenna radiation part and two feeding parts according to its functions. Among them, the radiation part is 64 back cavity patch units, and the feeding part 1 is fabricated on the second dielectric substrate 2, with 16 rectangular SIW dielectric cavity power dividers 2-1. This power divider operates in the TM12 higher-order mode and has a relatively wide reflection coefficient bandwidth. The feeding part 2 is fabricated on the third dielectric substrate 3, which can divide the electromagnetic energy from the port into 16 parts. Since the SIW feeding network occupies a large area, it is often impossible to directly feed the back cavity slot antenna unit physically. Through the SIW transmission line and combined with 1 rectangular SIW dielectric cavity power divider 2-1, the design of a 2×2 sub-array can be realized, as Figure 5 shown. Figure 6 The top views of the antenna unit, the 2×2 antenna sub-array, and the 8×8 array antenna are shown, which can conveniently compare the occupied areas of the three.

[0043] The -10 dB reflection coefficient bandwidth characteristics of the millimeter-wave broadband high-gain low-cross-polarization back cavity patch array antenna are as Figure 7 shown. For comparison, the -10 dB reflection coefficient bandwidth characteristics of the back cavity antenna unit and the 2×2 sub-array are also shown. The bandwidth of the antenna unit is very wide and can fully cover the designed frequency band. The bandwidth of the 2×2 sub-array is 36.8%, and the relative bandwidth of the 8×8 array antenna is 38.1%. Figure 8 The gain characteristics of this case are shown, where the maximum gain of the antenna unit reaches 11.2 dBi, the maximum gain of the 2×2 sub-array reaches 15.8 dBi, and the peak gain of the 8×8 array antenna reaches 27.5 dBi. Figure 9 The radiation pattern characteristics of the 8×8 array antenna in this case at 27 GHz are given. The main lobe width of the E-plane of the array antenna is about 9 degrees, the main lobe bandwidth of the H-plane is about 9 degrees, and the cross-polarization isolation is 62.5 dB. Figure 10 The radiation pattern characteristics of the 8×8 array antenna in this case at 30 GHz are given. The main lobe width of the E-plane of the array antenna is about 7.9 degrees, the main lobe bandwidth of the H-plane is about 7.9 degrees, and the cross-polarization isolation is 62 dB. Figure 11 The radiation pattern characteristics of the 8×8 array antenna in this case at 33 GHz are given. The main lobe width of the E-plane of the array antenna is about 7 degrees, the main lobe bandwidth of the H-plane is about 7 degrees, and the cross-polarization isolation is 59 dB. Figure 12The radiation pattern characteristics of the 8×8 array antenna in this case at 36 GHz are given. The E-plane main lobe width of the array antenna is approximately 6.7 degrees, the H-plane main lobe bandwidth is approximately 6.7 degrees, and the cross-polarization isolation is 61.1 dB. Figure 13 The variation relationship of the cross-polarization characteristics of the cavity-backed patch array antenna with frequency in this case is given, and the cross-polarization isolation is greater than 58.6 dB.

[0044] In summary, a millimeter-wave broadband high-gain low-cross-polarization cavity-backed patch array antenna provided in this embodiment has a wide frequency band of 38.1%, a high gain of 27.5 dBi, and a low-cross-polarization characteristic >58.6 dB, and has excellent electrical performance. At the same time, this embodiment has the characteristics of low profile, low processing cost, and easy integration.

Claims

1. A millimeter wave broadband high-gain low cross-polarization cavity-backed patch array antenna, which is an 8×8 array antenna, including 16 2×2 antenna subarrays, each 2×2 antenna subarray including 4 SIW cavity-backed patch antenna units (1-1), characterized in that: The invention comprises three layers of dielectric substrate and four layers of metal. Starting from the first metal layer, the metal layers and the dielectric substrate are stacked in an alternating manner from top to bottom until the fourth metal layer. All metal layers are connected by vertically penetrating metal through holes to maintain a direct current path state. 64 SIW back cavity patch antenna units (1-1) are printed on the first metal layer. Each of the SIW back cavity patch antenna units (1-1) comprises a grid (1-4) and a microstrip patch antenna arranged in the grid (1-4). The grid (1-4) comprises a plurality of metal lines arranged in a horizontal and vertical staggered manner. 64 grids (1-4) are formed between the metal lines. Each of the microstrip patch antenna units (1-1) comprises a plurality of metal lines arranged in a horizontal and vertical staggered manner. The line is provided with a patch break groove (1-8) to divide the patch antenna into two small patches (1-5); a plurality of regularly arranged metallized through holes are provided in the first dielectric substrate (1), all of which are connected to the metal lines of the first metal layer, vertically penetrate to the second metal layer, surround the grid, and form a rectangular SIW dielectric cavity (2-3); a regular top feeding slit (2-7) is etched below the second metal layer and above the second dielectric substrate, and a regular bottom feeding slit (2-4) is etched above the third metal layer and below the second dielectric substrate, the top feeding slit (2-7) being located directly below the patch break groove (1-8) and parallel to the patch break groove (1-8).

2. The millimeter-wave broadband high-gain low cross-polarization back cavity patch array antenna as described in claim 1, wherein the second dielectric substrate (2) uses metallized through holes to form 16 SIW dielectric cavity power dividers (2-1), and connects the second metal layer and the third metal layer, and each SIW dielectric cavity power divider (2-1) corresponds to a 2×2 antenna subarray; in the third dielectric substrate (3), the metallized through holes connect the third metal layer and the fourth metal layer to form a sixteen-way SIW broadband power divider feeding network.

3. The millimeter wave broadband high gain low cross polarization cavity backed patch array antenna according to claim 1, characterized in that: Three layers of dielectric substrates are stacked together to establish a coordinate system. In the rectangular coordinate system, the x-axis and the y-axis are parallel to the two rectangular sides of the PCB board respectively, the z-axis points to the maximum radiation direction of the array antenna, the sixteen-way SIW broadband power divider feeding network ports are parallel to the y direction, the long sides of the 16 four-way rectangular SIW dielectric cavity power dividers (2-1) are parallel to the x direction, and the long sides of all feeding slots are parallel to the x direction.

4. The millimeter wave broadband high gain low cross polarization cavity-backed patch array antenna according to any one of claims 1 to 3, characterized in that: Each small patch (1-5) is provided with a groove (1-6) at the middle position of the edge of the other end away from the patch break groove (1-8).

5. The millimeter wave broadband high-gain low cross-polarization cavity-backed patch array antenna according to any one of claims 1 to 3, characterized in that: A driving through hole (1-7) is provided at the middle position of each small patch (1-5), and the driving through hole (1-7) connects the small patch (1-5) and the second metal layer to form a direct current path state.

6. The millimeter wave broadband high-gain low cross-polarization cavity-backed patch array antenna according to any one of claims 1 to 3, characterized in that: Two rows of metallized through holes and six metallized matching through holes are arranged inside each of the SIW dielectric cavities (2-3), and the matching through holes are used to adjust the electromagnetic energy distribution in the dielectric cavity.

7. The millimeter wave broadband high gain low cross polarization cavity backed patch array antenna according to claim 6, characterized in that: The first matching through holes (2-5) are located at both ends of the bottom feeding slot (2-4) and are used to adjust the matching condition of the bottom feeding slot (2-4); the second matching through holes (2-5) are located at both ends of the through hole array (2-8) and are used to adjust the matching condition of the top feeding slot (2-7).

8. The millimeter wave broadband high-gain low cross-polarization cavity-backed patch array antenna according to any one of claims 1 to 3, characterized in that: The sixteen-way SIW broadband power divider feeding network comprises a large H-type section connected in parallel with four small H-type sections (3-1), four bottom feeding gaps (2-4) are etched on the third metal layer at the end of each small H-type section (3-1), a SIW through hole connects the third metal layer and the fourth metal layer, and each of the small H-type sections (3-1) comprises an inductive matching through hole (3-2) and a SIW transmission line (3-3).

9. The millimeter wave broadband high gain low cross polarization cavity backed patch array antenna as claimed in claim 8, characterized in that: A SIW transmission line (3-3) is arranged in the third dielectric substrate (3), and a port is connected to other millimeter wave radio frequency systems through the SIW transmission line (3-3) or is connected to an antenna testing device through a switching structure.

10. The millimeter wave broadband high-gain low cross-polarization cavity-backed patch array antenna according to any one of claims 1 to 3, 7 and 9, characterized in that: The dielectric constants of the first dielectric substrate (1), the second dielectric substrate (2), and the third dielectric substrate (3) are all 2.2, and the loss tangent is 0.0009. The first dielectric substrate (1), the second dielectric substrate (2), and the third dielectric substrate (3) use Taconic TLY5, which has a dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 1.016 mm.

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