A low-profile, wide-axis-ratio beam, dual-sensor, dual-frequency circularly polarized antenna

Abstract

The present invention provides a low-profile, wide-axial-ratio dual-sensor, dual-frequency circularly polarized antenna, comprising a first dielectric plate, a second dielectric plate, a circular metal patch, a rectangular metal patch, a metal floor, and a coaxial line. The second dielectric plate is disposed above the first dielectric plate. The circular metal patch is printed on the upper surface of the second dielectric plate, the rectangular metal patch is printed on the upper surface of the first dielectric plate, and the metal floor is printed on the lower surface of the first dielectric plate. The coaxial line is introduced from below the first dielectric plate, the outer conductor of the coaxial line is electrically connected to the metal floor, and the inner conductor of the coaxial line passes through the first and second dielectric plates in sequence and is electrically connected to the rectangular and circular metal patches. The present invention has the characteristics of dual frequency, dual circular polarization, and a wide-axial-ratio beam, and can better meet the requirements of the Beidou navigation satellite system. The present invention also has the advantages of simple structure, low profile, and small size, making it easy to manufacture and facilitating the promotion and use of related technologies.

Description

Technical Field

[0001] The present invention relates to the field of communication antennas, and in particular to a low-profile, wide-axis-ratio beam, dual-sensor, dual-frequency circularly polarized antenna. Background Art

[0002] With the development of wireless communications, users are demanding increasingly higher communication quality. Antennas, as signal transmission devices in wireless communication systems, have a significant impact on the overall system's communication quality. Therefore, improving antenna performance is crucial. Circularly polarized antennas offer advantages over linearly polarized antennas, such as resistance to polarization mismatch and Faraday rotation. They can also receive any linearly polarized wave, improving polarization utilization. Furthermore, circularly polarized antennas exhibit polarization orthogonality, meaning circularly polarized waves of different rotation directions do not interfere with each other. Therefore, circularly polarized antennas can better ensure communication quality and are widely used in navigation, radio frequency identification, and detection systems.

[0003] As one of the global satellite navigation systems, the Beidou Navigation Satellite System not only provides positioning services but also supports short message communication services. For satellite navigation systems, to improve wireless communication system signal coverage and ensure wireless signal reception anywhere on Earth, the 3-dB axial ratio beamwidth of circularly polarized antennas should be as large as possible. Furthermore, for global navigation satellite systems, antenna size and axial ratio beamwidth are more important than bandwidth and gain. However, existing antennas generally suffer from complex feed structures, large size, and narrow beamwidth.

[0004] For example, in the 2019 issue of the IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS journal, Hong Cai Yang, in his article titled "A Compact Dual-Band Stacked Patch Antenna With DualCircular Polarizations for BeiDou Navigation Satellite Systems," proposed a compact dual-band, dual-circularly polarized patch antenna for the BeiDou Navigation Satellite System. This antenna utilizes a double-layer patch to achieve dual-band operation, and by loading the patch with branches to increase the impedance bandwidth, it achieves impedance bandwidths of 1.538–1.685 GHz and 2.40–2.525 GHz, 3-dB axial ratio bandwidths of 1.610–1.634 GHz and 2.472–2.500 GHz, and gains of 3.3 and 4.2 dBi, respectively. However, this antenna suffers from low axial ratio beamwidth and half-power beamwidth, as well as low gain, failing to meet the requirements of the BeiDou Navigation Satellite System. Therefore, further improvement and refinement of existing technologies is necessary. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-profile, wide-axial-ratio-beam, dual-sensing, dual-frequency circularly polarized antenna to address the above-mentioned defects in the prior art. The antenna not only realizes the dual-sensing, dual-frequency circularly polarized characteristics, but also realizes the characteristics of low profile and wide 3-dB axial-ratio beam to better meet the use requirements of the Beidou navigation satellite system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna comprising a first dielectric plate, a second dielectric plate, a circular metal patch, a rectangular metal patch, a metal floor, and a coaxial line;

[0008] The second dielectric plate is arranged above the first dielectric plate; the circular metal patch is printed on the upper surface of the second dielectric plate, the rectangular metal patch is printed on the upper surface of the first dielectric plate, and the metal floor is printed on the lower surface of the first dielectric plate;

[0009] The coaxial line is introduced from below the first dielectric plate, the outer conductor of the coaxial line is electrically connected to the metal floor, and the inner conductor of the coaxial line passes through the first dielectric plate and the second dielectric plate in sequence, and is electrically connected to the rectangular metal patch and the circular metal patch;

[0010] The center of the rectangular metal patch and the center of the circular metal patch are arranged to overlap with each other; the rectangular metal patch is square in shape as a whole, and a first rectangular cut corner, a second rectangular cut corner, a third rectangular cut corner, and a fourth rectangular cut corner are respectively provided at the four corners of the rectangular metal patch; each rectangular cut corner includes a bottom edge and two mutually parallel side edges, the two side edges of the rectangular cut corner and the adjacent side edges of the rectangular metal patch form a 45° angle, the bottom edge of the rectangular cut corner is perpendicularly connected between the two side edges and is located at an end close to the center of the rectangular metal patch, so that the rectangular cut corner forms a rectangular opening groove with an opening facing outward at the corner of the rectangular metal patch;

[0011] The circular metal patch is provided with a first rectangular slit, a second rectangular slit, a third rectangular slit and a fourth rectangular slit; the first rectangular slit, the second rectangular slit, the third rectangular slit and the fourth rectangular slit are respectively parallel to the bottom edges of the first rectangular cut corner, the second rectangular cut corner, the third rectangular cut corner and the fourth rectangular cut corner, and are respectively arranged between the center of the circular metal patch and the first rectangular cut corner, the second rectangular cut corner, the third rectangular cut corner and the fourth rectangular cut corner.

[0012] Furthermore, in the rectangular metal patch, the first rectangular cut corner and the fourth rectangular cut corner constitute a first group of rectangular cut corners, and the second rectangular cut corner and the third rectangular cut corner constitute a second group of rectangular cut corners; the first group of rectangular cut corners and the second group of rectangular cut corners are arranged orthogonally to each other;

[0013] The first rectangular cut corner and the fourth rectangular cut corner are respectively arranged at a set of opposite corners of the rectangular metal patch, and both have the same size and are symmetrical about the center of the rectangular metal patch;

[0014] The second rectangular cut corner and the third rectangular cut corner are respectively arranged at another set of opposite corners of the rectangular metal patch, have the same size, and are symmetrical about the center of the rectangular metal patch.

[0015] Furthermore, the sizes of the first set of rectangular cut corners and the second set of rectangular cut corners are not equal to each other; by adjusting the sizes of the first set of rectangular cut corners and the second set of rectangular cut corners and their distances to the center of the rectangular metal patch, left-hand circular polarization is achieved in the low frequency band.

[0016] Furthermore, in the circular metal patch, the first rectangular slit and the fourth rectangular slit constitute a first group of rectangular slits, and the second rectangular slit and the third rectangular slit constitute a second group of rectangular slits; the first group of rectangular slits and the second group of rectangular slits are arranged orthogonally to each other;

[0017] The perpendicular bisectors of the first rectangular slit and the fourth rectangular slit coincide with each other, are of the same size, and are symmetrical about the center of the circular metal patch;

[0018] The perpendicular bisectors of the second rectangular slit and the third rectangular slit coincide with each other, are of the same size, and are symmetrical about the center of the circular metal patch.

[0019] Furthermore, the sizes of the first group of rectangular slits and the second group of rectangular slits are not equal to each other, and the distances from the first group of rectangular slits and the second group of rectangular slits to the center of the circular metal patch are not equal to each other; by adjusting the sizes of the first group of rectangular slits and the second group of rectangular slits and their distances to the center of the circular metal patch, right-hand circular polarization is achieved in the high frequency band.

[0020] Furthermore, the material of the first dielectric plate is Rogers RT5880.

[0021] Furthermore, the material of the second dielectric plate is Taconic TLYR.

[0022] Furthermore, the second dielectric plate is stacked on the first dielectric plate, and there is no air layer between the first dielectric plate and the second dielectric plate.

[0023] Furthermore, the width of the first set of rectangular cut corners is 8.2 mm, the width of the second set of rectangular cut corners is 5.6 mm, and the distances from the first set of rectangular cut corners and the second set of rectangular cut corners to the center of the rectangular metal patch are 30 mm.

[0024] Furthermore, the length of the first set of rectangular slits is 12 mm, the width is 0.6 mm, and the distance to the center of the circular metal patch is 25 mm; the length of the second set of rectangular slits is 8 mm, the width is 0.1 mm, and the distance to the center of the circular metal patch is 39 mm.

[0025] The present invention uses a coaxial line to feed two layers of metal patches simultaneously, achieving dual-frequency radiation. Furthermore, by etching rectangular cut corners and rectangular slits on the two layers of metal patches, the two layers of patches generate a pair of orthogonal modes, so that the antenna has equal far-field orthogonal electric field amplitudes and a 90° phase difference within a wide-angle range, forming dual-sense circularly polarized radiation. By changing the size of the rectangular cut corners and rectangular slits on each layer of metal patches, the circular polarization rotation directions in the low-frequency and high-frequency bands can be independently controlled.

[0026] Compared with existing technologies, the present invention improves the 3-dB axial ratio beamwidth and half-power beamwidth at low and high frequencies. Simulation results show that the antenna of the present invention achieves gains of 6.83 dBi and 7.32 dBi at 1.615 GHz and 2.492 GHz, respectively. Within both main radiation planes at both frequencies, the 3-dB axial ratio beamwidth is greater than 120°, and the half-power beamwidth is greater than 80°. The antenna exhibits high gain and excellent performance, better meeting the requirements of the Beidou navigation satellite system.

[0027] The four rectangular corner cuts and four rectangular slits in the present invention increase the freedom of perturbation adjustment, ensuring equal amplitudes and 90° phase shifts in the far-field orthogonal electric fields across a wide angle, thereby increasing the antenna's beamwidth. The present invention offers dual-frequency, dual-circular polarization, and a wide-axis-ratio beam, better meeting the requirements of the Beidou navigation satellite system. Furthermore, its simple structure, low profile, and compact size make it easy to manufacture and facilitate the promotion and application of related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural exploded diagram of a low-profile, wide-axis-ratio beam, dual-sensor, dual-frequency circularly polarized antenna provided by an embodiment of the present invention.

[0029] Figure 2 The figure is a top view of a low-profile, wide-axis-ratio beam, dual-sensor, dual-frequency circularly polarized antenna provided by an embodiment of the present invention.

[0030] Figure 3 is the S11 simulation result of the antenna according to the embodiment of the present invention.

[0031] Figure 4 1 is the axial ratio bandwidth simulation result of the antenna according to the embodiment of the present invention.

[0032] Figure 5These are the simulation results of the axial ratio beamwidth (phi=0°, 45°, 90°, 135°) of the antenna according to the embodiment of the present invention when operating at 1.615 GHz.

[0033] Figure 6 These are the simulation results of the axial ratio beamwidth (phi=0°, 45°, 90°, 135°) of the antenna according to the embodiment of the present invention when operating at 2.492 GHz.

[0034] Figure 7 1 is a simulation result of the radiation pattern of the antenna according to an embodiment of the present invention when operating at 1.615 GHz (phi=0°, 90°).

[0035] Figure 8 These are the radiation pattern simulation results (phi=0°, 90°) of the antenna according to the embodiment of the present invention when operating at 2.492 GHz.

[0036] Figure 9 These are the simulation results of the half-power beamwidth (phi=0°, 45°, 90°, 135°) of the antenna according to an embodiment of the present invention when operating at 1.615 GHz.

[0037] Figure 10 These are the simulation results of the half-power beamwidth (phi=0°, 45°, 90°, 135°) of the antenna according to an embodiment of the present invention when operating at 2.492 GHz. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] like Figure 1 As shown, an embodiment of the present invention provides a low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna, comprising a first dielectric plate 11, a second dielectric plate 12, a circular metal patch 2, a rectangular metal patch 3, a metal floor 4, and a coaxial line 5;

[0040] The second dielectric plate 12 is arranged above the first dielectric plate 11; the circular metal patch 2 is printed on the upper surface of the second dielectric plate 12, the rectangular metal patch 3 is printed on the upper surface of the first dielectric plate 11, and the metal floor 4 is printed on the lower surface of the first dielectric plate 11;

[0041] The coaxial line 5 is introduced from the bottom of the first dielectric plate 11, the outer conductor of the coaxial line 5 is electrically connected to the metal floor 4, and the inner conductor of the coaxial line 5 passes through the first dielectric plate 11 and the second dielectric plate 12 in sequence, and is electrically connected to the rectangular metal patch 3 and the circular metal patch 2.

[0042] In order to facilitate the intuitive comparison of the specific structures and spatial positional relationships of the circular metal patch 2 and the rectangular metal patch 3, Figure 2 In FIG, the circular metal patch 2 and the rectangular metal patch 3 are drawn on the same projection plane. Specifically, Figure 2 As shown, the center of the rectangular metal patch 3 and the center of the circular metal patch 2 are arranged to overlap each other.

[0043] The rectangular metal patch 3 is square in shape as a whole, and a first rectangular cut corner 31, a second rectangular cut corner 32, a third rectangular cut corner 33 and a fourth rectangular cut corner 34 are respectively provided at the four corners of the rectangular metal patch 3; each rectangular cut corner includes a bottom side and two mutually parallel side sides, and the two side sides of the rectangular cut corner form a 45° angle with the adjacent side sides of the rectangular metal patch 3, and the bottom side of the rectangular cut corner is vertically connected between the two side sides and is located at one end close to the center of the rectangular metal patch 3, so that the rectangular cut corner forms a rectangular open groove with the opening facing outward at the corner of the rectangular metal patch 3.

[0044] The circular metal patch 2 is provided with a first rectangular slit 21, a second rectangular slit 22, a third rectangular slit 23 and a fourth rectangular slit 24; the first rectangular slit 21, the second rectangular slit 22, the third rectangular slit 23 and the fourth rectangular slit 24 are respectively parallel to the bottom edges of the first rectangular cut corner 31, the second rectangular cut corner 32, the third rectangular cut corner 33 and the fourth rectangular cut corner 34, and are respectively arranged between the center of the circular metal patch 2 and the first rectangular cut corner 31, the second rectangular cut corner 32, the third rectangular cut corner 33 and the fourth rectangular cut corner 34.

[0045] Specifically, the length direction of the first rectangular slit 21 is parallel to the bottom side of the first rectangular cut corner 31, and the first rectangular slit 21 is arranged in the space between the center of the circular metal patch 2 and the first rectangular cut corner 31; the length direction of the second rectangular slit 22 is parallel to the bottom side of the second rectangular cut corner 32, and the second rectangular slit 22 is arranged in the space between the center of the circular metal patch 2 and the second rectangular cut corner 32; the length direction of the third rectangular slit 23 is parallel to the bottom side of the third rectangular cut corner 33, and the third rectangular slit 23 is arranged in the space between the center of the circular metal patch 2 and the third rectangular cut corner 33; the length direction of the fourth rectangular slit 24 is parallel to the bottom side of the fourth rectangular cut corner 34, and the fourth rectangular slit 24 is arranged in the space between the center of the circular metal patch 2 and the fourth rectangular cut corner 34.

[0046] The embodiment of the present invention simultaneously feeds two layers of metal patches through the coaxial line 5, thereby realizing dual-frequency characteristics. At the same time, the rectangular cut corners and the rectangular slits respectively generate different circular polarizations in the low-frequency and high-frequency bands, thereby realizing dual-sensing characteristics.

[0047] Furthermore, in the rectangular metal patch 3, the first rectangular cut corner 31 and the fourth rectangular cut corner 34 constitute a first group of rectangular cut corners, and the second rectangular cut corner 32 and the third rectangular cut corner 33 constitute a second group of rectangular cut corners; the first group of rectangular cut corners and the second group of rectangular cut corners are arranged orthogonally to each other;

[0048] The first rectangular cut corners 31 and the fourth rectangular cut corners 34 are respectively provided at a set of opposite corners of the rectangular metal patch 3, are of the same size, and are symmetrical about the center of the rectangular metal patch 3. The second rectangular cut corners 32 and the third rectangular cut corners 33 are respectively provided at another set of opposite corners of the rectangular metal patch 3, are of the same size, and are symmetrical about the center of the rectangular metal patch 3. However, the sizes of the first set of rectangular cut corners and the second set of rectangular cut corners are not equal.

[0049] By controlling the width (i.e., the distance between the two parallel sides of the rectangular cutouts) and lengths of the two sets of rectangular cutouts, perturbations can separate a pair of orthogonal modes on the rectangular metal patch 3. This ensures that the antenna's far-field orthogonal electric fields have equal amplitudes and a 90° phase difference over a wide angle range, resulting in circularly polarized radiation. In this embodiment, the width of the first set of rectangular cutouts is 8.2 mm, and the width of the second set is 5.6 mm. The distance from the first and second sets of rectangular cutouts to the center of the rectangular metal patch (i.e., the distance from the bottom edge of the rectangular cutouts to the center of the rectangular metal patch) is 30 mm. Based on this structure, the antenna can achieve left-handed circularly polarized waves in the low-frequency band.

[0050] Furthermore, in the circular metal patch 2, the first rectangular slit 21 and the fourth rectangular slit 24 constitute a first group of rectangular slits, and the second rectangular slit 22 and the third rectangular slit 23 constitute a second group of rectangular slits; the first group of rectangular slits and the second group of rectangular slits are arranged orthogonally to each other;

[0051] The perpendicular bisectors of the first and fourth rectangular slits 21 and 24 coincide with each other, are of equal size, and are symmetrical about the center of the circular metal patch 2. The perpendicular bisectors of the second and third rectangular slits 22 and 23 coincide with each other, are of equal size, and are symmetrical about the center of the circular metal patch 2. However, the sizes of the first and second groups of rectangular slits are different, and the distances from the first and second groups of rectangular slits to the center of the circular metal patch are different.

[0052] By controlling the size of the two sets of rectangular slits and their distance from the center of the circle, perturbations can separate a pair of orthogonal modes on the circular metal patch 2, ensuring that the antenna's far-field orthogonal electric fields have equal amplitudes and a 90° phase difference over a wide angle, resulting in circularly polarized radiation. In this embodiment, the first set of rectangular slits is 12mm long, 0.6mm wide, and 25mm away from the center of the circular metal patch; the second set of rectangular slits is 8mm long, 0.1mm wide, and 39mm away from the center of the circular metal patch. Based on this structure, the antenna can achieve right-handed circularly polarized waves in the high-frequency band.

[0053] Furthermore, the second dielectric plate 12 is stacked above the first dielectric plate 11, with no air layer between the first and second dielectric plates 11 and 12. In this embodiment, the first dielectric plate 11 is made of Rogers RT5880, which has a relative dielectric constant of 2.2 and a loss tangent of 0.0009; the second dielectric plate 12 is made of Taconic TLYR, which has a relative dielectric constant of 2.2 and a loss tangent of 0.0009.

[0054] The dimensions of the low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna provided in this embodiment are 70 mm × 70 mm × 4.575 mm (0.38λ0 × 0.38λ0 × 0.024λ0). The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna of this embodiment was verified and simulated using HFSS simulation software.

[0055] Figure 3 The S11 parameter (input port return loss) of the antenna in the frequency range of 1.4-2.6 GHz is given. It can be seen that the frequency bands where S11 ≤ -10 dB are 1.60-1.65 GHz and 2.49-2.56 GHz, with relative bandwidths of 3% and 2.8%.

[0056] Figure 4 The AR (axial ratio) of the antenna in the frequency range of 1.4-2.6 GHz is given. It can be seen that the frequency bands with AR ≤ 3 dB are 1.61-1.62 GHz and 2.48-2.5 GHz, and the relative bandwidths are 0.6% and 0.8%.

[0057] Figure 5 and Figure 6 The 3-dB axial ratio beam of the antenna of this embodiment in four sections is given. Figure 5 It can be seen from the figure that at 1.615GHz, when phi=0°, 45°, 90°, and 135°, the 3-dB axial ratio beamwidth of the antenna is 146°, 195°, 171°, and 123° respectively. Figure 6As can be seen in the figure, at 2.492 GHz, when phi = 0°, 45°, 90°, and 135°, the antenna's 3-dB axial ratio beamwidth is 126°, 106°, 141°, and 189°, respectively. In both principal planes, when phi = 0° and 90°, the 3-dB axial ratio beamwidth at 1.615 GHz and 2.492 GHz is greater than 120°.

[0058] Figure 7 The main plane radiation pattern of the antenna at 1.615 GHz is given. It can be seen from the figure that the antenna of this embodiment has left-hand circular polarization performance at 1.615 GHz and a maximum gain of 6.8 dBi.

[0059] Figure 8 The main plane radiation pattern of the antenna at 2.492 GHz is given. It can be seen from the figure that the antenna of this embodiment has right-hand circular polarization performance at 2.492 GHz and a maximum gain of 7.3 dBi.

[0060] Figure 9 and Figure 10 The half-power beamwidth of the antenna of this embodiment in four sections is given. Figure 9 It can be seen from the figure that at 1.615GHz, when phi=0°, 45°, 90°, and 135°, the half-power beamwidth is 89°, 89°, 88°, and 89° respectively. Figure 10 As can be seen in the figure, at 2.492 GHz, when phi = 0°, 45°, 90°, and 135°, the half-power beamwidth is 82°, 83°, 82°, and 84°, respectively. In the two principal planes, when phi = 0° and 90°, the half-power beamwidth at 1.615 GHz and 2.492 GHz is greater than 80°.

[0061] Based on the above simulation results, compared with existing dual-sensor, dual-frequency circularly polarized antennas, the low-profile, wide-axial-ratio dual-sensor, dual-frequency circularly polarized antenna of this embodiment has good 3-dB beamwidth and half-power beamwidth, high gain, and stable dual circularly polarized radiation performance. Therefore, the low-profile, wide-axial-ratio dual-frequency circularly polarized antenna of the present invention is well suited for use in the Beidou satellite navigation system.

[0062] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna, characterized in that: It includes a first dielectric plate, a second dielectric plate, a circular metal patch, a rectangular metal patch, a metal floor and a coaxial line; The second dielectric plate is arranged above the first dielectric plate; the circular metal patch is printed on the upper surface of the second dielectric plate, the rectangular metal patch is printed on the upper surface of the first dielectric plate, and the metal floor is printed on the lower surface of the first dielectric plate; The coaxial line is introduced from below the first dielectric plate, the outer conductor of the coaxial line is electrically connected to the metal floor, and the inner conductor of the coaxial line passes through the first dielectric plate and the second dielectric plate in sequence, and is electrically connected to the rectangular metal patch and the circular metal patch; The center of the rectangular metal patch and the center of the circular metal patch are arranged to overlap with each other; the rectangular metal patch is square in shape as a whole, and a first rectangular cut corner, a second rectangular cut corner, a third rectangular cut corner, and a fourth rectangular cut corner are respectively provided at the four corners of the rectangular metal patch; each rectangular cut corner includes a bottom edge and two mutually parallel side edges, the two side edges of the rectangular cut corner and the adjacent side edges of the rectangular metal patch form a 45° angle, the bottom edge of the rectangular cut corner is perpendicularly connected between the two side edges and is located at an end close to the center of the rectangular metal patch, so that the rectangular cut corner forms a rectangular opening groove with an opening facing outward at the corner of the rectangular metal patch; The circular metal patch is provided with a first rectangular slit, a second rectangular slit, a third rectangular slit, and a fourth rectangular slit; the first rectangular slit, the second rectangular slit, the third rectangular slit, and the fourth rectangular slit are respectively parallel to the bottom edges of the first rectangular cut corner, the second rectangular cut corner, the third rectangular cut corner, and the fourth rectangular cut corner, and are respectively provided between the center of the circular metal patch and the first rectangular cut corner, the second rectangular cut corner, the third rectangular cut corner, and the fourth rectangular cut corner; In the rectangular metal patch, the first rectangular cut corner and the fourth rectangular cut corner constitute a first group of rectangular cut corners, and the second rectangular cut corner and the third rectangular cut corner constitute a second group of rectangular cut corners; the first group of rectangular cut corners and the second group of rectangular cut corners are arranged orthogonally to each other; The first rectangular cut corner and the fourth rectangular cut corner are respectively arranged at a set of opposite corners of the rectangular metal patch, and both have the same size and are symmetrical about the center of the rectangular metal patch; The second rectangular cut corner and the third rectangular cut corner are respectively arranged at another set of opposite corners of the rectangular metal patch, and both have the same size and are symmetrical about the center of the rectangular metal patch; In the circular metal patch, the first rectangular slit and the fourth rectangular slit constitute a first group of rectangular slits, and the second rectangular slit and the third rectangular slit constitute a second group of rectangular slits; the first group of rectangular slits and the second group of rectangular slits are arranged orthogonally to each other; The perpendicular bisectors of the first rectangular slit and the fourth rectangular slit coincide with each other, are of the same size, and are symmetrical about the center of the circular metal patch; The perpendicular bisectors of the second rectangular slit and the third rectangular slit coincide with each other, are of the same size, and are symmetrical about the center of the circular metal patch.

2. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 1, characterized in that: The sizes of the first set of rectangular cut corners and the second set of rectangular cut corners are not equal to each other; by adjusting the sizes of the first set of rectangular cut corners and the second set of rectangular cut corners and their distances to the center of the rectangular metal patch, left-hand circular polarization is achieved in the low frequency band.

3. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 1, characterized in that: The sizes of the first group of rectangular slits and the second group of rectangular slits are not equal to each other, and the distances from the first group of rectangular slits and the second group of rectangular slits to the center of the circular metal patch are not equal to each other; by adjusting the sizes of the first group of rectangular slits and the second group of rectangular slits and the distances from them to the center of the circular metal patch, right-hand circular polarization is achieved in the high frequency band.

4. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 1, characterized in that: The material of the first dielectric plate is Rogers RT5880.

5. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 1, characterized in that: The material of the second dielectric plate is Taconic TLYR.

6. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 1, characterized in that: The second dielectric plate is stacked on the first dielectric plate, and there is no air layer between the first dielectric plate and the second dielectric plate.

7. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 2, characterized in that: The width of the first set of rectangular cut corners is 8.2 mm, the width of the second set of rectangular cut corners is 5.6 mm, and the distance between the first set of rectangular cut corners and the second set of rectangular cut corners and the center of the rectangular metal patch is 30 mm.

8. The low-profile, wide-axis-ratio, dual-sensor, dual-frequency circularly polarized antenna according to claim 3, characterized in that: The length of the first set of rectangular slits is 12 mm, the width is 0.6 mm, and the distance to the center of the circular metal patch is 25 mm; the length of the second set of rectangular slits is 8 mm, the width is 0.1 mm, and the distance to the center of the circular metal patch is 39 mm.

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