A circularly polarized patch antenna and antenna array based on geometric center feeding

Abstract

A circularly polarized patch antenna and antenna array based on geometric center feeding, belonging to the field of antenna technology, solves the problems of complex design, high cost, high system loss and low radiation efficiency of existing circularly polarized phased array antennas. 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 and the low-frequency loop antenna are coaxial, 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 feeding network distribution of the entire array antenna, reducing the design difficulty of the feeding network, simplifying the feeding network design, and improving the feeding efficiency of the system. The two branches of the patch power divider extend the transmission path of the power branch to transmit the radio frequency signal due to the deviation angle, ensuring that at a certain deviation angle, the phase difference between the horizontal polarization and the vertical polarization is 90 degrees, and the amplitude of the vertical polarization and the horizontal polarization remain equal, meeting the circular polarization radiation conditions.

Description

Technical Field

[0001] The present 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 requirements for the functions of communication systems are increasing. In many application scenarios, phased array antennas can dynamically adjust the beam direction and track multiple targets, becoming an inevitable choice. In the field of communications, to ensure that the signals of cooperating users in different postures can be continuously and normally interconnected, antennas usually choose circular polarization working mode. Circularly polarized antennas can handle signal transmission in a variety of complex situations, resist multipath interference, and have a wider range of application scenarios. Therefore, compared with conventional linearly polarized 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, they also need 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 units need to be optimized to obtain broadband, wide-angle, low cross-polarization performance. However, this goal is difficult to achieve in actual engineering, especially in the case of wide bandwidth and angle scanning. Because the polarization pattern 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 requirement. Existing technologies usually rotate the unit antennas in the array according to a certain pattern to obtain the average effect of the spatial circular polarization field, thereby improving and enhancing 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-circular-polarized antenna unit and a dual-circular-polarized antenna. It 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. It uses a power divider and a 3dB bridge to realize four-point rotation and mirror-symmetrical feeding of the left-hand and right-hand circularly polarized antenna units, thereby improving the axial ratio index characteristics of the 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. In terms of 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 are 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 the 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 this will increase the system loss; (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 existing circularly polarized phased array antennas.

[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 provided 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 provided 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] Metal through-holes are provided at the geometric centers of the third dielectric layer and the metal plate. A feeding structure is provided on the lower surface of the metal plate, and the inner conductor of the feeding structure is connected to the upper surface of the third dielectric layer through the metal through-hole. 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 at a certain angle relative to the perpendicular midline of the metal plate, 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-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 a 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 a low-frequency loop antenna.

[0012] Furthermore, the first power branch deviates 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 first dielectric layer and the third dielectric layer are made of the same dielectric material, both 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 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 present invention can effectively reduce the antenna cross-sectional height, save the space of the patch antenna, improve the antenna aperture area utilization, make the overall structure of the antenna more compact, and reduce the manufacturing cost.

[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° under a certain deviation angle. Since the energy balance of the three-port network is difficult, the amplitude of the vertical polarization and the horizontal polarization is kept equal by adding a resistor element between the two power branches, meeting the circular polarization radiation conditions, effectively utilizing the spatial structure, and completing energy distribution.

[0022] (3) The present invention arranges the high-frequency circular antenna and the low-frequency loop antenna coaxially, which can reduce the impedance mismatch between the low-frequency antenna and the high-frequency antenna, enhance the overlap of the electromagnetic field, and enable the low-frequency loop antenna to more effectively transfer energy to the high-frequency circular antenna. The coaxial arrangement can maintain the phase consistency of the signal, 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 arrangement 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 direction and interference.

[0023] (4) In an antenna array, the axial ratio performance of the entire antenna array can be improved by rotating each antenna unit to any angle. 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 and the low-frequency loop antenna are coaxial, so that the feeding structure can be fed at the geometric center of the antenna unit. When the antenna unit is rotated, it does not affect the distribution of the feeding network of the entire 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 1 is an exploded view of a circularly polarized patch antenna based on geometric center feeding according to the first embodiment of the present invention;

[0025] Figure 2 1 is a front view of a circularly polarized patch antenna based on geometric center feeding according to a 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 Schematic diagram of the deviation angle of the first power branch path according to 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 graph of the right-hand circularly polarized wave axis ratio of the antenna according to the first embodiment of the present invention;

[0030] FIG7( a ) is a diagram showing the effect of multi-angle rotation of antenna units in a 2×2 antenna array according to the first embodiment of the present invention;

[0031] FIG7( b ) is a diagram showing the effect of multi-angle rotation of antenna units in a 2×2 antenna array under the prior art according to the first embodiment 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] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

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

[0035] Example 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 provided 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 provided 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] Metal through holes are provided at the geometric centers 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. The inner conductor of the feeding structure 42 is connected to the upper surface of the third dielectric layer 31 through the metal through hole. The metal plate 41 is square.

[0040] A patch power divider 33 is further provided on the upper surface of the third dielectric layer 31. 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 bisector 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 and the RF signal on the second power branch 332 have the same amplitude, and the phase difference between the horizontal polarization and the vertical polarization is 90°.

[0042] Furthermore, the first power branch 331 includes a first rectangular microstrip line, a first curved microstrip line, a second rectangular microstrip line, a second curved 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-shaped microstrip line, a fifth rectangular microstrip line, a fifth arc-shaped microstrip line and a sixth rectangular microstrip line 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; the first rectangular microstrip line, the first curved microstrip line, and the second rectangular microstrip line are symmetrically arranged along the angle bisector with the fourth rectangular microstrip line, the fourth curved 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 curved microstrip line is greater than the length of the fifth curved microstrip line;

[0047] 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 32 .

[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 antenna aperture area utilization, make the overall structure of the antenna more compact, and reduce manufacturing costs.

[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 power branch is greater than that of the other power branch, which extends the transmission path of the radio frequency 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 in a 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 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 an antenna array, the axial ratio performance of the entire antenna array can be improved by rotating each antenna unit to any angle. The present invention sets the feed 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. This allows the feed structure 42 to feed at the geometric center of the antenna unit. Rotating the antenna unit does not affect the distribution of the feed network for the entire array antenna, reducing the design difficulty of the feed network, simplifying the feed network design, reducing system losses, lowering production costs, and improving the system's feeding efficiency.

[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 coaxially arranged to reduce impedance mismatch between the low-frequency and high-frequency antennas. This enhances electromagnetic field overlap, allowing the low-frequency loop antenna 32 to more efficiently transfer energy to the high-frequency circular antenna 12. This coaxial arrangement maintains signal phase alignment, improving radiation efficiency and signal quality, ensuring that the high-frequency antenna radiates signals in the intended manner and enhancing overall antenna performance. Furthermore, while ensuring that unnecessary radiation directions and interference are eliminated, this coaxial arrangement simplifies the antenna structure, reduces the complexity of the overall antenna design, and optimizes the antenna's radiation characteristics.

[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 constant is 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 dielectric with a relative dielectric constant of 1.0 and a thickness of 2 mm. The first dielectric layer 11 and the third dielectric layer 31 are made of the same dielectric material, both 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 an energy signal 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 radio frequency signal into 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 chip power divider 33 is symmetrically arranged along the perpendicular midline of the metal plate 41 , that is, the position of the chip power divider 33 is changed, left-handed circularly polarized radiation will be generated accordingly.

[0063] like Figure 5 This is a simulation curve of the S11 parameter of the antenna's right-hand circular polarization input port. The S11 parameter is an important indicator among S parameters, indicating the ratio of reflected power to incident power. The data in the figure shows that the S11 parameter of the antenna's 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 antenna normal axial ratio is less than 3 dB is 6.31 GHz-7.79 GHz, and the relative axial ratio bandwidth is 21%.

[0064] 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 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 coaxial with the feed point, no matter how the antenna unit is rotated to any angle, the feed 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, simplifying the feeding network design and reducing the design difficulty of the feeding network, which 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, which sets the feeding point at the geometric center of the antenna unit, the prior art greatly increases the complexity and cost of the antenna engineering design and production.

[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 they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. 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 various embodiments of the present invention.

Claims

1. A circularly polarized patch antenna based on geometric center feeding, characterized in that: comprising 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 provided 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 provided 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 each 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 via the metal through-hole; and the metal plate is square; A patch power divider is further 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 and the input end of the second power branch intersect 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 at a certain angle relative to the perpendicular midline of the metal plate, 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 curved microstrip line, a second rectangular microstrip line, a second curved 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; the first rectangular microstrip line, the first curved microstrip line, and the second rectangular microstrip line are symmetrically arranged along the angle bisector with the fourth rectangular microstrip line, the fourth curved 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 curved microstrip line is greater than the length of the fifth curved 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 deviates by 5° relative to the perpendicular midline of the metal plate.

4. The 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, and the high-frequency circular antenna emits a circularly polarized radiation signal.

6. The 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 first dielectric layer, the second dielectric layer and the third dielectric layer are made of the same dielectric material, and all have relative dielectric constants of 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 first and third dielectric layers are made of the same dielectric material 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 according to any one of claims 1 to 8.

Images