Circularly polarized antenna

Abstract

The circularly polarized antenna comprises a dielectric substrate, a first bottom plate, a second bottom plate, a first radiation sheet, a second radiation sheet, a first feed line, a second feed line, a first connecting column, a second connecting column and a plurality of metal grounding columns. The dielectric substrate comprises a first surface and a second surface which are oppositely arranged. The dielectric substrate is provided with a first feed hole, a second feed hole and a plurality of grounding holes. The first radiation sheet is arranged in the first metal hole, the first radiation sheet is not in contact with the first bottom plate, and the first radiation sheet is provided with a gap. And the first feed circuit is arranged in the third metal hole and is not in contact with the second bottom plate. And the second feed circuit is arranged in the fourth metal hole and is not in contact with the second bottom plate. And the gaps arranged on the antenna radiation sheet can generate resonance at different frequency points, so that the bandwidth of the antenna is increased. Mutual coupling between antennas and interference of reflection signals on the antennas can be reduced, and the antenna performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a circularly polarized antenna. BACKGROUND

[0002] In recent years, with the increasing maturity of UWB technology development, UWB communication technology has been widely used in various fields, such as indoor positioning, unmanned vehicles, industrial automation, and angle and distance measurement of car keys.

[0003] The core of UWB communication technology for angle measurement is the angle measurement of PDOA, which is a unique technical advantage of UWB. PDOA uses two receiving antennas with a small distance to measure the angle of arrival of the target. Compared with other AOA technology routes, UWB PDOA can realize smaller anchor base stations, and has the advantages of high-precision TOF ranging of UWB, and obtains angle + high-precision ranging position space perception. This technology has high requirements for the design of UWB antennas. In order to meet the angle measurement requirements, the design requirements of the antenna are quite high. The existing antennas have mutual coupling between the antennas and the interference of reflected signals, which has a certain influence on the angle and distance measurement work. SUMMARY

[0004] The present application aims to provide a circularly polarized antenna which can reduce the mutual coupling between the antennas and the interference of reflected signals, and provide the working performance of the antenna for angle and distance measurement.

[0005] The present application provides a circularly polarized antenna, which comprises a dielectric substrate, a first bottom plate, a second bottom plate, a first radiation sheet, a second radiation sheet, a first feed line, a second feed line, a first connecting column, a second connecting column, and a plurality of metal grounding columns.

[0006] Specifically, along the first direction, the dielectric substrate comprises a first surface and a second surface arranged oppositely, the dielectric substrate is provided with a first feed hole, a second feed hole and a plurality of grounding holes, the first feed hole, the second feed hole and the plurality of grounding columns penetrate the first surface and the second surface. The first bottom plate is arranged on the first surface, and the second bottom plate is arranged on the second surface. The first bottom plate is provided with a first metal hole and a second metal hole, and the second bottom plate is provided with a third metal hole and a fourth metal hole.

[0007] The first radiation patch is arranged in the first metal hole and does not contact the first bottom plate, and the first radiation patch is provided with a first circular slot, a first square slot and a third square slot. In the second direction, the first radiation patch includes a first edge and a third edge, and the first square slot and the third square slot are respectively located on both sides of the first circular slot, the first square slot penetrates the first edge, and the third square slot penetrates the third edge. The second radiation patch is arranged in the second metal hole and does not contact the first bottom plate. The first feed line is arranged in the third metal hole and does not contact the second bottom plate. The second feed line is arranged in the fourth metal hole and does not contact the second bottom plate. The first connecting column is arranged in the first feed hole and connected to the first radiation patch at one end and connected to the first feed line at the other end. The second connecting column is arranged in the second feed hole and connected to the second radiation patch at one end and connected to the second feed line at the other end. The plurality of metal grounding stakes are arranged in the plurality of grounding holes.

[0008] The first direction is along the thickness direction of the dielectric substrate, and the second direction is perpendicular to the first direction.

[0009] In the above scheme, the two metal bottom plates serve as a ground reference, which can reduce the stray radiation of the feed network and improve the signal quality. The two radiation patches can excite orthogonal polarization modes, produce a phase difference, improve the gain, and enhance the radiation efficiency. The slots arranged on the antenna radiation patch can resonate at different frequency points, increasing the antenna bandwidth. The mutual coupling between the antennas and the interference of the reflected signal on the antenna can be reduced, and the working performance of the antenna angle measurement and angle measurement can be improved.

[0010] In some embodiments, the first radiation patch includes a communication device, the first circular slot divides the first radiation patch into a first part and a second part, the first part and the second part are connected through the communication device, and the first square slot and the third square slot are arranged in the first part. The circular slot and the communication device jointly act on the antenna, change the capacitive and inductive characteristics of the antenna, produce resonance in the required frequency band, greatly increase the antenna bandwidth, and realize the bandwidth of the antenna.

[0011] In some embodiments, the first radiating sheet is provided with a fifth square slot and a seventh square slot. In the third direction, the first radiating sheet includes a fifth edge and a seventh edge, the fifth edge being perpendicular to the first edge, and the seventh edge being perpendicular to the first edge. The fifth square slot penetrates the fifth edge, and the seventh square slot penetrates the seventh edge. The first direction, the second direction, and the third direction are perpendicular to each other in pairs. Increasing the number of slots can increase the resonant points of the antenna, thereby expanding the working bandwidth.

[0012] Further, the first square slot and the third square slot are symmetrically arranged, and the fifth square slot and the seventh square slot are arranged on the midlines of the fifth edge and the seventh edge. By symmetrically arranging the slots, uniform current distribution is achieved, cross polarization is reduced, and circular polarization purity is improved.

[0013] In some embodiments, the center of the first circular slot is located at the geometric center of the first radiating sheet. The number of first square slots is at least two, and the number of third square slots is at least two. By increasing the number of slots, the resonant points of the antenna can be increased, thereby expanding the working bandwidth.

[0014] In some embodiments, the second radiating sheet is provided with a second circular slot, a second square slot, and a fourth square slot. In the second direction, the second radiating sheet includes a second edge and a fourth edge, and the second square slot and the fourth square slot are located on the two sides of the second circular slot, respectively. The second square slot penetrates the second edge, and the fourth square slot penetrates the fourth edge. By arranging the same slots on the second radiating sheet as on the first radiating sheet, the coupling of orthogonal polarization components can be enhanced, and circular polarization can be enhanced.

[0015] Further, the second radiating sheet is provided with a sixth square slot and an eighth square slot. In the third direction, the second radiating sheet includes a sixth edge and an eighth edge, the sixth edge being perpendicular to the second edge, and the eighth edge being perpendicular to the second edge. The sixth square slot penetrates the sixth edge, and the eighth square slot penetrates the eighth edge. The resonant points can be further increased, and the frequency band can be widened by the superposition effect. The first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0016] Further, the second square slot and the fourth square slot are symmetrically arranged, and the sixth square slot and the eighth square slot are arranged on the midlines of the sixth edge and the eighth edge. Further by symmetrically arranging the slots, uniform current distribution is achieved, cross polarization is reduced, and circular polarization purity is improved.

[0017] In some embodiments, the center of the second circular slot is located at the geometric center of the second radiating patch; the number of the second square slots is at least two, and the number of the fourth square slots is at least two. The resonant points of the antenna can be better increased, thereby expanding the working bandwidth.

[0018] In some embodiments, the first radiating patch and the second radiating patch are symmetrically arranged about the middle line of the first surface. By symmetrically arranging two radiating patches, symmetry can be provided, cross polarization caused by asymmetric excitation can be reduced, and the stability of the phase difference can also be more easily maintained.

[0019] Additional aspects and advantages of embodiments of the present application will be described in part in the description that follows, and will be shown in part by way of exemplary embodiments that can be practiced. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which demonstrate aspects of the embodiments. It is to be understood that the same or similar elements shown in different embodiments can be referenced with a common numeral for the sake of clarity and illustration. In addition, the dimensions of the various features in the figures can be exaggerated for clarity of presentation and are not necessarily to scale.

[0021] Figure 1 An exploded view of a circularly polarized antenna according to some embodiments of the present application;

[0022] Figure 2 A top view of a circularly polarized antenna according to some embodiments of the present application;

[0023] Figure 3 A bottom view of a circularly polarized antenna according to some embodiments of the present application;

[0024] Figure 4 A front view of a circularly polarized antenna according to some embodiments of the present application;

[0025] Figure 5 A structural schematic diagram of a first radiating patch according to some embodiments of the present application;

[0026] Figure 6 A structural schematic diagram of a first radiating patch according to some embodiments of the present application;

[0027] Figure 7 A structural schematic diagram of a second radiating patch according to some embodiments of the present application;

[0028] Figure 8 A structural schematic diagram of a second radiating patch according to some embodiments of the present application;

[0029] Figure 9 A reflection simulation coefficient diagram of an antenna port according to some embodiments of the present application;

[0030] Figure 10H-plane (magnetic field plane) radiation pattern for some embodiments of the present application;

[0031] Figure 11 E-plane (electric field plane) radiation pattern for some embodiments of the present application;

[0032] Figure 12 PDOA (Phase Difference of Arrival) phase curve for some embodiments of the present application.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] 1, dielectric substrate;

[0035] 21, first radiating sheet; 211, first edge; 2111, first square slot; 213, third edge; 2131, third square slot; 215, fifth edge; 2151, fifth square slot; 217, seventh edge; 2171, seventh square slot; 219, first circular slot; 21a, first portion; 21b, second portion; 210, communication device; 22, second radiating sheet; 222, second edge; 2221, second square slot; 224, fourth edge; 2241, fourth square slot; 226, sixth edge; 2261, sixth square slot; 228, eighth edge; 2281, eighth square slot; 220, second circular slot;

[0036] 31, first bottom plate; 311, first metal hole; 312, second metal hole; 32, second bottom plate; 321, third metal hole; 322, fourth metal hole;

[0037] 41, first connecting column; 42, second connecting column;

[0038] 51, first feeding line; 52, second feeding line;

[0039] X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Various modifications can be made to the described embodiments, and some of which have specifically been pointed out.

[0041] Reference in this specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of other embodiments.

[0042] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0043] The technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0044] The present application proposes a circularly polarized antenna, please refer to Figure 1 , comprising a dielectric substrate 1, a first bottom plate 31, a second bottom plate 32, a first radiation sheet 21, a second radiation sheet 22, a first feed line 51, a second feed line 52, a first connecting column 41, a second connecting column 42 and a plurality of metal grounding columns (not shown in the figure).

[0045] Specifically, along the first direction X, the dielectric substrate 1 comprises a first surface (not shown in the figure) and a second surface (not shown in the figure) arranged oppositely, the dielectric substrate 1 is provided with a first feed hole, a second feed hole and a plurality of grounding holes (not shown in the figure), the first feed hole (not shown in the figure), the second feed hole (not shown in the figure) and the plurality of grounding columns penetrate the first surface and the second surface.

[0046] The first bottom plate 31 is arranged on the first surface, and the second bottom plate 32 is arranged on the second surface; the first bottom plate 31 is provided with a first metal hole 311 and a second metal hole 312, and the second bottom plate 32 is provided with a third metal hole 321 and a fourth metal hole 322. The first bottom plate 31 can be coupled with the radiation sheet to excite different electromagnetic wave modes, produce resonance, and achieve the purpose of expanding the bandwidth of the antenna. It can be understood that the bottom plate is made of high-conductivity metal, which can reduce energy loss, such as copper or aluminum material.

[0047] Please refer to Figure 2 , the first radiation sheet 21 is arranged in the first metal hole 311, the first radiation sheet 21 does not contact the first bottom plate 31, and the first radiation sheet 21 is provided with a first circular slot 219, a first square slot 2111 and a third square slot 2131; along the second direction Y, the first radiation sheet 21 comprises a first edge 211 and a third edge 213, and the first square slot 2111 and the third square slot 2131 are respectively located on both sides of the first circular slot 219, the first square slot 2111 penetrates the first edge 211, and the third square slot 2131 penetrates the third edge 213; the second radiation sheet 22 is arranged in the second metal hole 312, and the second radiation sheet 22 does not contact the first bottom plate 31. The bandwidth can be expanded by opening the slot, and the slot structure can be set according to the requirement, such as the same length of the first square slot 2111 and the third square slot 2131.

[0048] Please refer to Figure 3 , the first feeding line 51 is arranged in the third metal hole 321 and does not contact the second bottom plate 32; the second feeding line 52 is arranged in the fourth metal hole 322 and does not contact the second bottom plate 32. The first connecting column 41 is arranged in the first feeding hole and one end is connected with the first radiation patch 21 and the other end is connected with the first feeding line 51; the second connecting column 42 is arranged in the second feeding hole and one end is connected with the second radiation patch 22 and the other end is connected with the second feeding line 52.

[0049] A plurality of metal grounding stakes are arranged in a plurality of grounding holes. It can be understood that the grounding column can provide physical support, and the number and position of the grounding column also affect the current distribution on the surface of the antenna, and at the same time have an influence on the circular polarization purity of the circularly polarized antenna, so the position layout of the plurality of grounding holes can be set according to the needs, such as uniformly arranging the plurality of grounding holes at the position close to the edge of the dielectric substrate 1, uniformly arranging the plurality of grounding holes at the position close to the center line of the dielectric substrate 1, and arranging the plurality of grounding holes at the position close to the first metal hole 311 and the second metal hole 312. A plurality of grounding stakes are arranged therein.

[0050] Among them, the first direction X is along the thickness direction of the dielectric substrate 1, and the second direction Y is perpendicular to the first direction X.

[0051] In the above scheme, two metal bottom plates serve as ground references, which can reduce the stray radiation of the feeding network and improve the signal quality. Two radiation patches can excite orthogonal polarization modes, produce phase differences, improve gain, and enhance radiation efficiency. The slots arranged on the antenna radiation patches can resonate at different frequency points, increasing the antenna bandwidth. This antenna can better meet the working requirements of angle measurement and distance measurement. At the same time, the antenna structure is simple, the processing technology is simple, the production cost is low, and it is easy to mass produce.

[0052] In some embodiments, please refer to Figure 5 and Figure 6 , the first radiation patch 21 includes a communication device 210, a first circular slot 219 divides the first radiation patch 21 into a first part 21a and a second part 21b, the first part 21a and the second part 21b are connected through the communication device 210, and a first square slot 2111 and a third square slot 2131 are arranged in the first part 21a. The circular slot and the communication device 210 jointly act on the antenna, which can change the capacitive and inductive characteristics of the antenna, produce resonance in the required frequency band, greatly increase the antenna bandwidth, and realize the bandwidth of the antenna.

[0053] In some embodiments, the first radiation sheet 21 is provided with a fifth square slot 2151 and a seventh square slot 2171; along the third direction Z, the first radiation sheet 21 comprises a fifth edge 215 and a seventh edge 217, the fifth edge 215 and the first edge 211 are perpendicular to each other, and the seventh edge 217 and the first edge 211 are perpendicular to each other; the fifth square slot 2151 penetrates through the fifth edge 215, and the seventh square slot 2171 penetrates through the seventh edge 217.

[0054] The first direction X, the second direction Y and the third direction Z are perpendicular to each other. By increasing the slots, the resonant points of the antenna can be increased, thereby expanding the working bandwidth.

[0055] Further, the first square slot 2111 and the third square slot 2131 are symmetrically arranged, and the fifth square slot 2151 and the seventh square slot 2171 are arranged on the midlines of the fifth edge 215 and the seventh edge 217. By symmetrically arranging the slots, uniform current distribution is achieved, cross-polarization is reduced, and circular polarization purity is improved.

[0056] In some embodiments, the center of the first circular slot 219 is located at the geometric center of the first radiation sheet 21; the number of the first square slots 2111 is at least two, and the number of the third square slots 2131 is at least two. By increasing the number of slots, the resonant points of the antenna can be increased, thereby expanding the working bandwidth.

[0057] In some embodiments, referring to Figure 7 and Figure 8 , the second radiation sheet 22 is provided with a second circular slot 220 and a second square slot 2221 and a fourth square slot 2241; along the second direction Y, the second radiation sheet 22 comprises a second edge 222 and a fourth edge 224, and the second square slot 2221 and the fourth square slot 2241 are located on the two sides of the second circular slot 220 respectively, the second square slot 2221 penetrates through the second edge 222, and the fourth square slot 2241 penetrates through the fourth edge 224. By arranging the same slots on the second radiation sheet 22 as on the first radiation sheet 21, the coupling of the orthogonal polarization components can be enhanced, and the circular polarization can be enhanced. It can be understood that the second circular slot 220 also divides the second radiation sheet 22 into two parts, and the two parts are connected by a connecting member.

[0058] Further, the second radiation sheet 22 is provided with a sixth square slot 2261 and an eighth square slot 2281; along the third direction, the second radiation sheet 22 comprises a sixth edge 226 and an eighth edge 228, the sixth edge 226 and the second edge 222 are perpendicular to each other, and the eighth edge 228 and the second edge 222 are perpendicular to each other; the sixth square slot 2261 penetrates through the sixth edge 226, and the eighth square slot 2281 penetrates through the eighth edge 228. The resonant points can be further increased, and the frequency band can be widened by superposition effect.

[0059] The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0060] Further, the second square slot 2221 and the fourth square slot 2241 are symmetrically arranged, and the sixth square slot 2261 and the eighth square slot 2281 are arranged on the midline of the sixth edge 226 and the eighth edge 228. Further, by symmetrically arranging the slots, uniform current distribution is achieved, cross polarization is reduced, and circular polarization purity is improved.

[0061] In some embodiments, the center of the second circular slot 220 is located at the geometric center of the second radiation patch 22; the number of the second square slot 2221 is at least two, and the number of the fourth square slot 2241 is at least two. The resonant points of the antenna can be better increased, thereby expanding the working bandwidth.

[0062] In some embodiments, the first radiation patch 21 and the second radiation patch 22 are symmetrically arranged about the midline of the first surface. By symmetrically arranging the two radiation patches, symmetry can be provided, cross polarization caused by asymmetric excitation can be reduced, and the stability of the phase difference can also be maintained more easily.

[0063] The simulation diagrams of some embodiments are provided as shown in Figures 9 to 12 .

[0064] Specifically, please refer to Figure 9 , Figure 9 The reflection simulation coefficient diagram of the antenna port of some embodiments is shown in the figure. As can be seen from the figure, the S parameter (scattering parameter) of the antenna, the reflection coefficient and the transmission coefficient are low, which can reflect that the energy reflection of the antenna is small, and the antenna mutual coupling can be effectively reduced.

[0065] Please refer to Figure 10 and Figure 11 , Figure 10 The H plane (magnetic field plane) radiation pattern of the antenna at 8 GHz is shown in Figure 11 The E plane (electric field plane) radiation pattern of the antenna at 8 GHz is shown in Figure 10 and Figure 11 The patterns reflected are relatively uniform, and the bandwidth of the antenna is relatively wide.

[0066] Please refer to Figure 12 , Figure 12 The PDOA (path difference of arrival) curve of the dual antenna is shown in the figure. The monotonicity of the curve is good, which can reflect that the direct wave of the antenna is dominant, the reflection is small, and the measurement accuracy is good.

[0067] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; under the idea of the present application, the technical features in the above examples or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for simplicity; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A circularly polarized antenna, characterized by, The antenna includes a dielectric substrate, a first bottom plate, a second bottom plate, a first radiating sheet, a second radiating sheet, a first feeding line, a second feeding line, a first connecting column, a second connecting column, and a plurality of metal grounding columns. In a first direction, the dielectric substrate includes oppositely arranged first and second surfaces, and the dielectric substrate is provided with a first feeding hole, a second feeding hole, and a plurality of grounding holes, the first feeding hole, the second feeding hole, and the plurality of grounding columns penetrating the first and second surfaces. The first bottom plate is arranged on the first surface, and the second bottom plate is arranged on the second surface; the first bottom plate is provided with a first metal hole and a second metal hole, and the second bottom plate is provided with a third metal hole and a fourth metal hole. The first radiating sheet is arranged in the first metal hole and does not contact the first bottom plate, and the first radiating sheet is provided with a first circular gap, a first square gap, and a third square gap; in a second direction, the first radiating sheet includes a first edge and a third edge, and the first square gap and the third square gap are respectively located on both sides of the first circular gap, the first square gap penetrates the first edge, and the third square gap penetrates the third edge; the second radiating sheet is arranged in the second metal hole and does not contact the first bottom plate. The first feeding line is arranged in the third metal hole and does not contact the second bottom plate; the second feeding line is arranged in the fourth metal hole and does not contact the second bottom plate. The first connecting column is arranged in the first feeding hole and connected to the first radiating sheet at one end and to the first feeding line at the other end; the second connecting column is arranged in the second feeding hole and connected to the second radiating sheet at one end and to the second feeding line at the other end. The plurality of metal grounding columns are arranged in the plurality of grounding holes. The first direction is along the thickness direction of the dielectric substrate, and the second direction is perpendicular to the first direction.

2. The circularly polarized antenna of claim 1, wherein, The first radiating sheet includes a communicating vessel, the first circular gap divides the first radiating sheet into a first part and a second part, the first part and the second part are connected through the communicating vessel, and the first square gap and the third square gap are arranged in the first part.

3. The circularly polarized antenna of claim 1, wherein, The first radiating sheet is provided with a fifth square gap and a seventh square gap; in a third direction, the first radiating sheet includes a fifth edge and a seventh edge, the fifth edge and the first edge are perpendicular to each other, and the seventh edge and the first edge are perpendicular to each other; the fifth square gap penetrates the fifth edge, and the seventh square gap penetrates the seventh edge. The first direction, the second direction, and the third direction are perpendicular to each other.

4. The circularly polarized antenna of claim 3, wherein, The first square gap and the third square gap are symmetrically arranged, and the fifth square gap and the seventh square gap are arranged on the midline of the fifth edge and the seventh edge.

5. The circularly polarized antenna of claim 1, wherein, The center of the first circular slit is located at the geometric center of the first radiation sheet; the number of the first square slits is at least two, and the number of the third square slits is at least two.

6. The circularly polarized antenna of claim 1, wherein, The second radiation sheet is provided with a second circular slit, a second square slit and a fourth square slit; along the second direction, the second radiation sheet comprises a second edge and a fourth edge, and the second square slit and the fourth square slit are respectively located on both sides of the second circular slit, the second square slit penetrates through the second edge, and the fourth square slit penetrates through the fourth edge.

7. The circularly polarized antenna of claim 6, wherein, The second radiation sheet is provided with a sixth square slit and an eighth square slit; along a third direction, the second radiation sheet comprises a sixth edge and an eighth edge, the sixth edge and the second edge are perpendicular to each other, and the eighth edge and the second edge are perpendicular to each other; the sixth square slit penetrates through the sixth edge, and the eighth square slit penetrates through the eighth edge. The first direction, the second direction and the third direction are perpendicular to each other.

8. The circularly polarized antenna of claim 7, wherein, The second square slit and the fourth square slit are symmetrically arranged, and the sixth square slit and the eighth square slit are arranged on the midlines of the sixth edge and the eighth edge.

9. The circularly polarized antenna of claim 6, wherein, The center of the second circular slit is located at the geometric center of the second radiation sheet; the number of the second square slits is at least two, and the number of the fourth square slits is at least two.

10. The circularly polarized antenna of claim 1, wherein, The first radiation sheet and the second radiation sheet are symmetrically arranged about the midline of the first surface.

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