Circularly polarized patch antenna based on geometric center feed and antenna array

Abstract

The invention discloses a circular polarization patch antenna based on geometric center feed and an antenna array, belongs to the technical field of antennas, and solves the problems of complex design, high cost, high system loss and low radiation efficiency of an existing circular polarization phased-array antenna. The feed point is arranged at the geometric center of the metal plate and the plurality of dielectric layers, and the high-frequency circular antenna and the low-frequency annular antenna are coaxial, so that the feed structure can feed at the geometric center of the antenna unit, the feed network distribution of the whole array antenna is not influenced when the antenna unit rotates, the design difficulty of the feed network is reduced, and the design efficiency is improved. The design of a feed network is simplified, the feed efficiency of the system is improved, two branches of the patch power divider extend the transmission path for transmitting radio frequency signals of the power branches due to the deviation angle, it is guaranteed that the phase difference of horizontal polarization and vertical polarization is 90 degrees under a certain deviation angle, the amplitude of vertical polarization and the amplitude of horizontal polarization are kept equal, and the power distribution efficiency of the system is improved. And circularly polarized radiation conditions are satisfied.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and relates to a circularly polarized patch antenna and an antenna array based on geometric center feeding. Background Art

[0002] With the development of society, people's functional requirements for communication systems are increasing. In many application scenarios, phased array antennas can dynamically adjust the beam direction and track multiple targets, which has become an inevitable choice. In the field of communications, in order to ensure that the signals of cooperative users in different postures can be continuously and normally interconnected, antennas usually choose circular polarization working mode. Circular polarization antennas can handle the transmission of signals in a variety of complex situations, resist multipath interference, and have a wider range of application scenarios. Therefore, compared with conventional linear polarization radar phased arrays, circularly polarized phased array antennas can achieve high gain, flexible beam scanning and shaping, and have superior antenna characteristics. At the same time, it is also necessary to meet the low axial ratio requirements of the antenna to reduce the system polarization mismatch loss.

[0003] In the process of building a circularly polarized phased array, in order to achieve good low axial ratio performance, the antenna unit needs to be optimized to obtain broadband, wide-angle, low cross-polarization performance. However, it is difficult to achieve this goal in actual engineering, especially in the case of wide bandwidth and angle scanning. Since the polarization mode of the antenna is closely related to the operating frequency, when the frequency range increases, signals of different frequencies will cause the radiation pattern and polarization state of the antenna to change, and the antenna axial ratio will deteriorate rapidly, making it difficult to maintain the low axial ratio requirements. The existing technology usually rotates the unit antennas in the array according to a certain rule to obtain the average benefit of the spatial circular polarization field, so as to improve and enhance the overall array antenna axial ratio and other performance. For example, the invention patent with application publication number CN118738881A discloses a wide-angle, low-axial-ratio four-fed dual circularly polarized antenna unit and a dual circularly polarized antenna, which adopts a central rotationally symmetrical structure to realize the radiation layer, improves the axial ratio of the circularly polarized antenna, and ensures the symmetry of the array antenna pattern; uses a power divider and a 3dB bridge to realize four-point rotation and mirror-symmetrical feeding of left- and right-hand circularly polarized antenna units, thereby improving the axial ratio index characteristics of dual circular polarization within a wide angle.

[0004] There are many types of circularly polarized antenna units, which are classified into single-point feeding, dual-point feeding and four-point feeding structures according to the feeding method. Considering the various circularly polarized units, their feeding points are all deviated from the geometric center of the antenna. Therefore, there are the following defects when constructing a rotational layout phased array: (1) When rotating according to the geometric center of the antenna unit, the positions of the feeding points of each circularly polarized unit in the array appear irregularly arranged, resulting in irregular layout and installation of the T / R components directly connected to the antenna unit in the phased array system, increasing the complexity and cost of system engineering. This is especially true in the tile-type integration method. At this time, an additional transmission line is required to regularize the feeding position in the array so that it can adapt to the regular active network port, but in this case, the system loss will increase; (2) When rotating according to the feeding point, a regular layout of the feeding points in the array will be obtained, but the positions of the antenna units in the array will be irregular, resulting in a decrease in the radiation efficiency of the array antenna aperture. Summary of the invention

[0005] The technical solution of the present invention is used to solve the problems of complex design, high cost, high system loss and low radiation efficiency of the existing circularly polarized phased array antenna.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A circularly polarized patch antenna based on geometric center feeding, comprising a first dielectric layer, a second dielectric layer, a third dielectric layer and a metal plate arranged in parallel from top to bottom;

[0008] A high-frequency circular antenna is disposed on the upper surface of the first dielectric layer, and the center of the high-frequency circular antenna coincides with the geometric center of the first dielectric layer; a low-frequency loop antenna is disposed on the upper surface of the third dielectric layer, and the center of the low-frequency loop antenna coincides with the geometric center of the third dielectric layer;

[0009] A metal through hole is provided at the geometric center of the third dielectric layer and the metal plate, a feeding structure is provided on the lower surface of the metal plate, an inner conductor of the feeding structure is connected to the upper surface of the third dielectric layer through the metal through hole, and the metal plate is square; a patch power divider is also provided on the upper surface of the third dielectric layer, and the patch power divider is arranged in the inner ring of the low-frequency loop antenna; the patch power divider includes a first power branch, a second power branch and a resistor; the input end of the first power branch intersects with the input end of the second power branch at the metal through hole; the output end of the first power branch and the output end of the second power branch are respectively connected to the low-frequency loop antenna;

[0010] The first power branch deviates from the perpendicular midline of the metal plate at a certain angle, the length of the first power branch is greater than the length of the second power branch, the RF signal on the first power branch has the same amplitude as the RF signal on the second power branch, and the phase difference between the horizontal polarization and the vertical polarization is 90°.

[0011] Furthermore, the first power branch includes a first rectangular microstrip line, a first arc microstrip line, a second rectangular microstrip line, a second arc microstrip line and a third rectangular microstrip line connected in sequence; the second power branch includes a fourth rectangular microstrip line, a fourth arc microstrip line, a fifth rectangular microstrip line, a fifth arc microstrip line and a sixth rectangular microstrip line connected in sequence; the input end of the first rectangular microstrip line is perpendicular to the input end of the fourth rectangular microstrip line and intersects at a metal through hole, and the first rectangular microstrip line, the first arc microstrip line and the second rectangular microstrip line are symmetrically arranged along the angle bisector with the fourth rectangular microstrip line, the fourth arc microstrip line and the fifth rectangular microstrip line respectively; one end of the resistor is connected to the second rectangular microstrip line, and the other end of the resistor is connected to the fifth rectangular microstrip line, and the second rectangular microstrip line is arranged in parallel with the fifth rectangular microstrip line; the length of the second arc microstrip line is greater than the length of the fifth arc microstrip line; the output end of the third rectangular microstrip line and the output end of the sixth rectangular microstrip line are respectively connected to a low-frequency loop antenna.

[0012] Furthermore, the first power branch is offset by 5° relative to the perpendicular midline of the metal plate.

[0013] Furthermore, the side length of the metal plate is 30 mm.

[0014] Furthermore, the high-frequency circular antenna is coaxial with the low-frequency loop antenna, the low-frequency loop antenna transfers signal energy to the high-frequency circular antenna through electromagnetic coupling, and the high-frequency circular antenna emits a circularly polarized radiation signal.

[0015] Furthermore, the radius of the high-frequency circular antenna is 9 mm; the inner diameter of the low-frequency loop antenna is 4 mm and the outer diameter is 6 mm.

[0016] Furthermore, the dielectric materials of the first dielectric layer, the second dielectric layer and the third dielectric layer are the same, and the relative dielectric constants are all 2.94. The thickness of the first dielectric layer is 0.254 mm, the thickness of the second dielectric layer is 2 mm, and the thickness of the third dielectric layer is 0.762 mm.

[0017] Furthermore, the second dielectric layer is aerogel or air dielectric, with a relative dielectric constant of 1.0 and a thickness of 2 mm; the dielectric material of the first dielectric layer and the third dielectric layer is the same, with relative dielectric constants of 2.94, the thickness of the first dielectric layer is 0.254 mm, and the thickness of the third dielectric layer is 0.762 mm.

[0018] The present invention also provides an antenna array, comprising a plurality of antenna units, wherein the antenna units are the circularly polarized patch antennas based on geometric center feeding.

[0019] The advantages of the present invention are:

[0020] (1) The present invention arranges the patch power divider and the low-frequency loop antenna in the same layer on the third dielectric layer, and arranges the patch power divider in the inner ring space of the low-frequency loop antenna. Compared with the traditional layered design of antenna and power divider, the antenna profile height can be effectively reduced, the space of the patch antenna can be saved, the antenna aperture area utilization rate can be improved, the overall structure of the antenna can be made more compact, and the manufacturing cost can be reduced.

[0021] (2) Due to the deviation angle of the two branches of the patch power divider, the microstrip line length of one power branch is greater than that of the other power branch, which extends the transmission path of the RF signal of the power branch. By controlling the transmission path length of the power branch, it is ensured that the phase difference between the horizontal polarization and the vertical polarization is 90° at a certain deviation angle. Since the energy balance of the three-port network is difficult, a resistor element is added between the two power branches to ensure that the amplitudes of the vertical polarization and the horizontal polarization remain equal, meet the circular polarization radiation conditions, effectively utilize the space structure, and complete energy distribution.

[0022] (3) The present invention sets the high-frequency circular antenna and the low-frequency loop antenna to be coaxial, which can reduce the impedance mismatch between the low-frequency antenna and the high-frequency antenna, and can enhance the overlap of the electromagnetic field so that the low-frequency loop antenna can more effectively transfer energy to the high-frequency circular antenna. The coaxial setting can keep the phase of the signal consistent, improve the radiation efficiency and signal quality, ensure that the high-frequency antenna radiates the signal in the expected manner, and improve the overall performance of the antenna. In addition, the coaxial setting can simplify the antenna structure, reduce the complexity of the overall antenna design, and optimize the radiation characteristics of the antenna while ensuring unnecessary radiation directions and interference.

[0023] (4) In the antenna array, each antenna unit can be rotated to any angle to improve the axial ratio performance of the overall antenna array. The present invention sets the feeding point at the geometric center of the metal plate and multiple dielectric layers, and the high-frequency circular antenna is coaxial with the low-frequency loop antenna, so that the feeding structure can be fed at the geometric center of the antenna unit. When the antenna unit rotates, it does not affect the distribution of the feeding network of the overall array antenna, which reduces the design difficulty of the feeding network, simplifies the feeding network design, reduces system losses, reduces production costs, and improves the feeding efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an exploded diagram of a circularly polarized patch antenna based on geometric center feeding according to the first embodiment of the present invention;

[0025] Figure 2 is a front view of a circularly polarized patch antenna based on geometric center feeding according to the first embodiment of the present invention;

[0026] Figure 3 is a top view of the third dielectric layer of the first embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of the deviation angle of the first power branch path in the first embodiment of the present invention;

[0028] Figure 5 is a curve diagram of the parameters of the right-hand circularly polarized input port S11 of the antenna according to the first embodiment of the present invention;

[0029] Figure 6 is a curve diagram of the right-hand circularly polarized wave axis ratio of the antenna in the first embodiment of the present invention;

[0030] FIG. 7( a ) is a diagram showing the effect of multi-angle rotation of antenna units in a 2×2 antenna array according to Embodiment 1 of the present invention;

[0031] FIG. 7( b ) is a diagram showing the effect of multi-angle rotation of antenna units in a 2×2 antenna array according to the prior art of Embodiment 1 of the present invention;

[0032] Figure numerals: 11, first dielectric layer; 12, high-frequency circular antenna; 21, second dielectric layer; 31, third dielectric layer; 32, low-frequency loop antenna; 33, patch power divider; 331, first power branch; 332, second power branch; 333, resistor; 41, metal plate; 42, feeding structure. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0035] Embodiment 1

[0036] like Figure 1-3 As shown, specifically, a circularly polarized patch antenna based on geometric center feeding is disclosed, comprising a first dielectric layer 11, a second dielectric layer 21, a third dielectric layer 31 and a metal plate 41 arranged in parallel from top to bottom;

[0037] A high-frequency circular antenna 12 is disposed on the upper surface of the first dielectric layer 11, and the center of the high-frequency circular antenna 12 coincides with the geometric center of the first dielectric layer 11;

[0038] A low-frequency loop antenna 32 is disposed on the upper surface of the third dielectric layer 31, and the center of the low-frequency loop antenna 32 coincides with the geometric center of the third dielectric layer 31;

[0039] A metal through hole is provided at the geometric center of the third dielectric layer 31 and the metal plate 41, a feeding structure 42 is provided on the lower surface of the metal plate 41, and an inner conductor of the feeding structure 42 is connected to the upper surface of the third dielectric layer 31 through the metal through hole, and the metal plate 41 is square;

[0040] A patch power divider 33 is also provided on the upper surface of the third dielectric layer 31, and the patch power divider 33 is provided in the inner ring of the low-frequency loop antenna 32; the patch power divider 33 includes a first power branch 331, a second power branch 332 and a resistor 333; the input end of the first power branch 331 and the input end of the second power branch 332 intersect at a metal through hole; the output end of the first power branch 331 and the output end of the second power branch 332 are respectively connected to the low-frequency loop antenna 32;

[0041] like Figure 4 As shown, the first power branch 331 deviates from the perpendicular midline of the metal plate 41 by a certain angle, the length of the first power branch 331 is greater than the length of the second power branch 332, the RF signal on the first power branch 331 has the same amplitude as the RF signal on the second power branch 332, and the phase difference between the horizontal polarization and the vertical polarization is 90°.

[0042] Further, the first power branch 331 includes a first rectangular microstrip line, a first arc-shaped microstrip line, a second rectangular microstrip line, a second arc-shaped microstrip line and a third rectangular microstrip line connected in sequence;

[0043] The second power branch 332 includes a fourth rectangular microstrip line, a fourth arc microstrip line, a fifth rectangular microstrip line, a fifth arc microstrip line and a sixth rectangular microstrip line which are connected in sequence;

[0044] The input end of the first rectangular microstrip line is perpendicular to the input end of the fourth rectangular microstrip line and intersects at the metal through hole, and the first rectangular microstrip line, the first arc-shaped microstrip line, and the second rectangular microstrip line are symmetrically arranged along the angle bisector with the fourth rectangular microstrip line, the fourth arc-shaped microstrip line, and the fifth rectangular microstrip line respectively;

[0045] One end of the resistor 333 is connected to the second rectangular microstrip line, and the other end of the resistor 333 is connected to the fifth rectangular microstrip line, and the second rectangular microstrip line is arranged in parallel with the fifth rectangular microstrip line;

[0046] The length of the second arc-shaped microstrip line is greater than the length of the fifth arc-shaped microstrip line;

[0047] The output end of the third rectangular microstrip line and the output end of the sixth rectangular microstrip line are connected to the low-frequency loop antenna 32 respectively.

[0048] The present invention arranges the patch power divider 33 and the low-frequency loop antenna 32 on the third dielectric layer 31, and arranges the patch power divider 33 in the inner ring space of the low-frequency loop antenna 32. Compared with the traditional layered design of antenna and power divider, it can effectively reduce the antenna cross-sectional height, save the space of the patch antenna, improve the utilization rate of the antenna aperture area, make the overall structure of the antenna more compact, and reduce the manufacturing cost.

[0049] At the same time, due to the deviation angle of the two branches of the patch power divider 33, the microstrip line length of one of the power branches is greater than that of the other power branch, which extends the transmission path of the RF signal of the power branch. By controlling the transmission path length of the power branch, it is ensured that at a certain deviation angle, the phase difference between the horizontal polarization and the vertical polarization is 90°. Since energy balance is difficult in a three-port network, a resistor element is added between the two power branches to ensure that the amplitudes of the vertical polarization and the horizontal polarization remain equal, meet the circular polarization radiation conditions, effectively utilize the spatial structure, and complete energy distribution.

[0050] In addition, the present invention balances the energy distribution on both sides by adding a resistor 333 between the two power branches, thereby ensuring equal energy distribution.

[0051] In the antenna array, each antenna unit can be rotated to any angle to improve the axial ratio performance of the overall antenna array. The present invention sets the feeding point at the geometric center of the metal plate 41 and multiple dielectric layers, and the high-frequency circular antenna 12 is coaxial with the low-frequency loop antenna 32, so that the feeding structure 42 can be fed at the geometric center of the antenna unit. When the antenna unit rotates, it does not affect the distribution of the feeding network of the overall array antenna, which reduces the design difficulty of the feeding network, simplifies the feeding network design, reduces system losses, reduces production costs, and improves the feeding efficiency of the system.

[0052] Furthermore, the circularly polarized patch antenna provided by the present invention is not limited to circular antennas and coaxial feeding structures 42, but can also be applied to antenna models of other shapes and geometric center feeding structures 42, and has good application prospects.

[0053] In this embodiment, the feeding structure 42 is a feeding connector.

[0054] In this embodiment, the first dielectric layer 11 , the second dielectric layer 21 and the third dielectric layer 31 are all circular.

[0055] Furthermore, the first power branch 331 deviates from the perpendicular midline of the metal plate 41 by 5°.

[0056] Furthermore, the high-frequency circular antenna 12 is coaxial with the low-frequency loop antenna 32 , and the low-frequency loop antenna 32 transfers signal energy to the high-frequency circular antenna 12 through electromagnetic coupling, and the high-frequency circular antenna 12 emits a circularly polarized radiation signal.

[0057] In this embodiment, the high-frequency circular antenna 12 and the low-frequency loop antenna 32 are set to be coaxial, which can reduce the impedance mismatch between the low-frequency antenna and the high-frequency antenna, and can enhance the overlap of the electromagnetic field so that the low-frequency loop antenna 32 can more effectively transfer energy to the high-frequency circular antenna 12. The coaxial setting can keep the phase of the signal consistent, improve the radiation efficiency and signal quality, ensure that the high-frequency antenna radiates the signal in the expected manner, and improve the overall performance of the antenna. In addition, the coaxial setting can simplify the antenna structure, reduce the complexity of the overall antenna design, and optimize the radiation characteristics of the antenna while ensuring unnecessary radiation directions and interference.

[0058] Furthermore, the radius of the high-frequency circular antenna 12 is 9 mm; the inner diameter of the low-frequency loop antenna 32 is 4 mm, and the outer diameter is 6 mm; and the side length of the metal plate 41 is 30 mm.

[0059] Furthermore, the dielectric materials of the first dielectric layer 11, the second dielectric layer 21 and the third dielectric layer 31 are the same, and the relative dielectric constants are all 2.94. The thickness of the first dielectric layer 11 is 0.254 mm, the thickness of the second dielectric layer 21 is 2 mm, and the thickness of the third dielectric layer 31 is 0.762 mm.

[0060] Furthermore, the second dielectric layer 21 is aerogel or air medium, with a relative dielectric constant of 1.0 and a thickness of 2 mm; the dielectric material of the first dielectric layer 11 and the third dielectric layer 31 is the same, with a relative dielectric constant of 2.94, the thickness of the first dielectric layer 11 is 0.254 mm, and the thickness of the third dielectric layer 31 is 0.762 mm.

[0061] Working principle: The present invention inputs energy from the feeding structure 42 to the center of the patch power divider 33 through coaxial feeding. One of the power branches of the patch power divider 33 has a deviation angle, which extends the transmission path of the power branch and generates energy signals with the same amplitude and a phase difference of 90° between horizontal polarization and vertical polarization. The patch power divider 33 and the annular patch antenna share the same layer. The two power branches of the patch power divider 33 can directly input the RF signal to the low-frequency loop antenna 32. Since the high-frequency circular antenna 12 and the low-frequency loop antenna 32 are set to be coaxial, the energy signal is coupled from the low-frequency loop antenna 32 located in the third dielectric layer 31 to the high-frequency circular antenna 12 in the first dielectric layer 11 through electromagnetic coupling, and the entire antenna jointly generates right-handed circularly polarized radiation to the external space.

[0062] Furthermore, if the patch power divider 33 is symmetrically arranged along the perpendicular midline of the metal plate 41 , that is, the position of the patch power divider 33 is changed, left-handed circularly polarized radiation will be generated accordingly.

[0063] like Figure 5 The simulation curve of the S11 parameter of the antenna right-hand circular polarization input port is shown in the figure. The S11 parameter is an important indicator in the S parameter, which indicates the ratio of the reflected power to the incident power. From the data in the figure, we can see that the S11 parameter of the antenna circular polarization is less than -10dB in the frequency band of 5.75GHz to 7.86GHz, and the relative impedance bandwidth is 31%; Figure 6 As shown, the frequency band in which the normal axial ratio of the antenna is less than 3 dB is 6.31 GHz-7.79 GHz, and the relative axial ratio bandwidth is 21%.

[0064] The present invention further provides an antenna array, comprising a plurality of antenna units, wherein the antenna units are circularly polarized patch antennas based on geometric center feeding provided in this embodiment.

[0065] As shown in Figure 7(a), in this embodiment, multiple antenna units are combined into a 2×2 antenna array. To meet the low axial ratio performance requirements, each antenna unit is rotated to a different angle. However, since the geometric center of the antenna unit is coaxially arranged with the feeding point, no matter how the antenna unit is rotated to any angle, the feeding point and the geometric center of the antenna unit will not change due to the rotation of the antenna unit.

[0066] Furthermore, when applied to antenna arrays with a larger number of antenna units, the feeding network of the larger antenna array will not undergo any position changes due to the rotation of the antenna units. Any antenna unit in the antenna array can arbitrarily choose the rotation angle according to application requirements, which simplifies the feeding network design and reduces the difficulty of feeding network design, and has good application prospects.

[0067] As shown in Figure 7(b), the geometric center of the antenna unit and the feeding point are not coaxially arranged in the prior art. Compared with Figure 7(a), when the antenna unit rotates, the feeding point shifts with the rotation. When rotating at different angles, the position of the feeding point is different, resulting in different feeding grid structures corresponding to different rotation angles. Compared with the present invention that sets the feeding point at the geometric center of the antenna unit, the prior art greatly increases the complexity and cost of the engineering design and production of the antenna.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circularly polarized patch antenna based on geometric center feeding, characterized in that: It includes a first dielectric layer, a second dielectric layer, a third dielectric layer and a metal plate arranged in parallel from top to bottom; A high-frequency circular antenna is disposed on the upper surface of the first dielectric layer, and the center of the high-frequency circular antenna coincides with the geometric center of the first dielectric layer; A low-frequency loop antenna is disposed on the upper surface of the third dielectric layer, and the center of the low-frequency loop antenna coincides with the geometric center of the third dielectric layer; A metal through hole is provided at the geometric center of the third dielectric layer and the metal plate, a feeding structure is provided on the lower surface of the metal plate, an inner conductor of the feeding structure is connected to the upper surface of the third dielectric layer through the metal through hole, and the metal plate is square; A patch power divider is also provided on the upper surface of the third dielectric layer, and the patch power divider is provided in the inner ring of the low-frequency loop antenna; the patch power divider includes a first power branch, a second power branch and a resistor; the input end of the first power branch intersects with the input end of the second power branch at a metal through hole; the output end of the first power branch and the output end of the second power branch are respectively connected to the low-frequency loop antenna; The first power branch deviates from the perpendicular midline of the metal plate at a certain angle, the length of the first power branch is greater than the length of the second power branch, the RF signal on the first power branch has the same amplitude as the RF signal on the second power branch, and the phase difference between the horizontal polarization and the vertical polarization is 90°.

2. A circularly polarized patch antenna based on geometric center feeding according to claim 1, characterized in that: The first power branch includes a first rectangular microstrip line, a first arc-shaped microstrip line, a second rectangular microstrip line, a second arc-shaped microstrip line and a third rectangular microstrip line connected in sequence; The second power branch includes a fourth rectangular microstrip line, a fourth arc-shaped microstrip line, a fifth rectangular microstrip line, a fifth arc-shaped microstrip line and a sixth rectangular microstrip line connected in sequence; The input end of the first rectangular microstrip line is perpendicular to the input end of the fourth rectangular microstrip line and intersects at the metal through hole, and the first rectangular microstrip line, the first arc-shaped microstrip line, and the second rectangular microstrip line are symmetrically arranged along the angle bisector with the fourth rectangular microstrip line, the fourth arc-shaped microstrip line, and the fifth rectangular microstrip line respectively; One end of the resistor is connected to the second rectangular microstrip line, and the other end of the resistor is connected to the fifth rectangular microstrip line, and the second rectangular microstrip line is arranged in parallel with the fifth rectangular microstrip line; The length of the second arc-shaped microstrip line is greater than the length of the fifth arc-shaped microstrip line; The output end of the third rectangular microstrip line and the output end of the sixth rectangular microstrip line are respectively connected to the low-frequency loop antenna.

3. A circularly polarized patch antenna based on geometric center feeding according to claim 2, characterized in that: The first power branch is offset by 5° relative to the perpendicular midline of the metal plate.

4. A circularly polarized patch antenna based on geometric center feeding according to claim 3, characterized in that: The side length of the metal plate is 30 mm.

5. The circularly polarized patch antenna based on geometric center feeding according to claim 1, characterized in that: The high-frequency circular antenna is coaxial with the low-frequency loop antenna. The low-frequency loop antenna transfers signal energy to the high-frequency circular antenna through electromagnetic coupling. The high-frequency circular antenna emits a circularly polarized radiation signal.

6. A circularly polarized patch antenna based on geometric center feeding according to claim 5, characterized in that: The radius of the high-frequency circular antenna is 9 mm; the inner diameter of the low-frequency loop antenna is 4 mm and the outer diameter is 6 mm.

7. The circularly polarized patch antenna based on geometric center feeding according to claim 1, characterized in that: The dielectric materials of the first dielectric layer, the second dielectric layer and the third dielectric layer are the same, and the relative dielectric constants are all 2.

94. The thickness of the first dielectric layer is 0.254 mm, the thickness of the second dielectric layer is 2 mm, and the thickness of the third dielectric layer is 0.762 mm.

8. The circularly polarized patch antenna based on geometric center feeding according to claim 1, characterized in that: The second dielectric layer is aerogel or air dielectric, with a relative dielectric constant of 1.0 and a thickness of 2 mm; the dielectric material of the first dielectric layer and the third dielectric layer is the same, with relative dielectric constants of 2.94, the thickness of the first dielectric layer is 0.254 mm, and the thickness of the third dielectric layer is 0.762 mm.

9. An antenna array, characterized in that: It comprises a plurality of antenna units, wherein the antenna units are circularly polarized patch antennas based on geometric center feeding as described in any one of claims 1 to 8.

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