Circularly polarized complementary antenna applied to low-orbit satellite communication

Abstract

The application discloses a circularly polarized complementary antenna applied to low-orbit satellite communication, which comprises a first PCB plate, a second PCB plate and a third PCB plate which are sequentially stacked from top to bottom, the upper surface of the first PCB plate is provided with a plurality of triangular patches, the size structures of the triangular patches are the same and rotationally symmetrical about the center of the first PCB plate, the lower surface of the first PCB plate is provided with a plurality of delay lines corresponding to the triangular patches, a first metal through hole is formed in each triangular patch, the first metal through hole penetrates through the first PCB plate and extends to the delay line, the upper surface of the second PCB plate is provided with a first ground copper layer, the center of the first ground copper layer is provided with a cross-shaped gap, the upper surface of the third PCB plate is provided with a strip-line copper layer, the lower surface of the third PCB plate is provided with a second ground copper layer, the strip-line copper layer is provided with a feeding hole, and the feeding hole penetrates through the third PCB plate and extends to the second ground copper layer. The application expands the working frequency width of the antenna and realizes keeping low axial ratio under the condition of low elevation angle.

Description

Technical Field

[0001] This invention relates to the field of circularly polarized antenna technology, and more particularly to a circularly polarized complementary antenna for low-Earth orbit satellite communication. Background Technology

[0002] During low-Earth orbit satellite communication, the relative positions of the satellite and the antenna will change, so the communication system must also have the function of "tracking the satellite", that is, the radiation beam changes with the position of the satellite.

[0003] In existing satellite communication technologies, phased arrays are often used for beamforming to enable the radiated beam to track satellites. However, since the overall performance of a phased array depends on the coordinated operation of numerous antenna elements, when in low elevation angle applications, the antenna elements are prone to problems such as excessive axial ratio and insufficient gain, leading to a significant performance decline and making it difficult to ensure the stability and efficiency of satellite communication. Summary of the Invention

[0004] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a circularly polarized complementary antenna for low-Earth orbit satellite communication, which can not only extend the operating bandwidth of the antenna, but also maintain a low axial ratio under low elevation angle conditions, thereby improving the stability and reliability of low-Earth orbit satellite communication.

[0005] This invention provides a circularly polarized complementary antenna for low-Earth orbit satellite communication, comprising a first PCB board, a second PCB board, and a third PCB board stacked sequentially from top to bottom. The upper surface of the first PCB board has multiple triangular patches of identical size and rotationally symmetrical about the center of the first PCB board. The lower surface of the first PCB board has multiple delay lines corresponding to the triangular patches. Each triangular patch has a first metal through-hole that passes through the first PCB board and extends to the delay line. The upper surface of the second PCB board has a first ground copper layer with a cross-shaped slot at its center. The upper surface of the third PCB board has a copper layer with a wire, and the lower surface of the third PCB board has a second ground copper layer. The copper layer with the wire has a feed hole that passes through the third PCB board and extends to the second ground copper layer.

[0006] According to an embodiment of the present invention, a circularly polarized complementary antenna for low-Earth orbit satellite communication has at least the following beneficial effects:

[0007] This invention employs a triangular patch antenna as an electric dipole antenna and a slot antenna as a magnetic dipole antenna. Since both the electric and magnetic dipoles utilize rotational symmetry, circular polarization is achieved. The electric and magnetic dipoles share a cross-shaped slot as a feed source, forming a complementary antenna combination. This achieves low cross-polarization levels, stable gain, and low backfire levels, while also extending the antenna's operating bandwidth. Furthermore, a delay line is added to the dipole antenna to adjust the relative phase, ensuring that the feed phases of the electric and magnetic dipoles are synchronized, maintaining a low axial ratio even at low elevation angles. Additionally, phase modulation is achieved through the use of a cross-shaped slot and a copper layer feed; when the phase difference equals 90 degrees, the antenna achieves circular polarization radiation, thereby improving the stability and reliability of low-Earth orbit satellite communication.

[0008] According to some embodiments of the present invention, the adhesive layer further includes a first adhesive layer disposed between the first PCB board and the second PCB board and a second adhesive layer disposed between the second PCB board and the third PCB board, wherein the thickness of the first adhesive layer is greater than the thickness of the second adhesive layer, and the dielectric constant of the first adhesive layer is the same as that of the second adhesive layer.

[0009] According to some embodiments of the present invention, the number of delay lines is four, and the shape of the four delay lines is S-shaped.

[0010] According to some embodiments of the present invention, the number of triangular patches is four, and the two rectangular gaps between the four triangular patches intersect to form a cross-shaped gap, the geometric center of the cross-shaped gap coincides with the geometric center of the cross-shaped slit.

[0011] According to some embodiments of the present invention, the cross-shaped gap includes two rectangular gaps arranged at opposite angles, the two rectangular gaps having the same length and width, and the projection of the rectangular gaps onto the upper surface of the first PCB board coincides with the rectangular gap portion.

[0012] According to some embodiments of the present invention, the copper strip layer includes a first microstrip line and a second microstrip line vertically connected on the plane of the third PCB board, wherein the length of the first microstrip line is greater than the length of the second microstrip line, the width of the first microstrip line is less than the width of the second microstrip line, and the end of the second microstrip line is formed with a convex structure.

[0013] According to some embodiments of the present invention, the feed hole is disposed at one end of the first microstrip line, and the second ground copper layer is provided with a circular non-metallic region, the center of the circular non-metallic region coincides with the center of the feed hole, and the diameter of the circular non-metallic region is larger than the diameter of the feed hole.

[0014] According to some embodiments of the present invention, the first PCB board and the first adhesive layer have a plurality of corresponding second metal through holes, the plurality of second metal through holes are respectively arranged circumferentially along the edges of the first PCB board and the first adhesive layer, and the second metal through holes pass through the first PCB board and the first adhesive layer and extend to the first ground copper layer.

[0015] According to some embodiments of the present invention, the second PCB board, the third PCB board, and the second adhesive layer are provided with a plurality of corresponding third metal through holes. The plurality of third metal through holes are respectively arranged circumferentially along the edges of the second PCB board, the third PCB board, and the second adhesive layer, and the third metal through holes pass through the second PCB board, the third PCB board, and the second adhesive layer and extend to the second ground copper layer.

[0016] According to some embodiments of the present invention, the thickness of the first PCB board is greater than the thickness of the second PCB board, the thickness of the second PCB board and the thickness of the third PCB board are the same, the dielectric constant of the first PCB board is greater than the dielectric constant of the third PCB board, and the dielectric constant of the second PCB board is greater than the dielectric constant of the first PCB board.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0020] Figure 1 This is a schematic diagram of the overall structure of a circularly polarized complementary antenna for low-Earth orbit satellite communication provided in an embodiment of the present invention;

[0021] Figure 2 This is a top view of the first PCB board in an embodiment of the present invention;

[0022] Figure 3 This is a bottom view of the first PCB board in an embodiment of the present invention;

[0023] Figure 4 This is a top view of the second PCB board in an embodiment of the present invention;

[0024] Figure 5 This is a top view of the third PCB board in this embodiment of the invention;

[0025] Figure 6 This is a bottom view of the third PCB board in this embodiment of the invention.

[0026] Reference numerals: First PCB board 100, triangular patch 110, delay line 120, first metal via 130, cross-shaped gap 140, rectangular gap 141, second PCB board 200, first ground copper layer 210, cross-shaped gap 220, rectangular gap 221, third PCB board 300, strip copper layer 310, first microstrip line 311, second microstrip line 312, convex structure 313, second ground copper layer 320, circular non-metallic area 321, power supply via 330, first adhesive layer 400, second adhesive layer 500, second metal via 600, third metal via 700. Detailed Implementation

[0027] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0028] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the number itself, while "above," "below," "within," etc. are understood to include the number itself. "Any one" refers to one or more, and "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or multiple items. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0029] It should be noted that the terms "setting," "installing," and "connecting" in the embodiments of this invention should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in the embodiments of this invention in conjunction with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or a connection that allows for mutual communication; it can be a direct connection or an indirect connection through an intermediate medium.

[0030] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] During low-Earth orbit satellite communication, the relative positions of the satellite and the antenna will change, so the communication system must also have the function of "tracking the satellite", that is, the radiation beam changes with the position of the satellite.

[0032] In existing satellite communication technologies, phased arrays are often used for beamforming to enable the radiated beam to track satellites. However, since the overall performance of a phased array depends on the coordinated operation of numerous antenna elements, when in low elevation angle applications, the antenna elements are prone to problems such as excessive axial ratio and insufficient gain, leading to a significant performance decline and making it difficult to ensure the stability and efficiency of satellite communication.

[0033] Based on this, embodiments of the present invention provide a circularly polarized complementary antenna for low-Earth orbit satellite communication, which not only expands the antenna's operating bandwidth but also maintains a low axial ratio under low elevation angle conditions, thereby improving the stability and reliability of low-Earth orbit satellite communication.

[0034] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0035] Reference Figures 1 to 6 The circularly polarized complementary antenna for low-Earth orbit satellite communication according to an embodiment of the present invention includes a first PCB board 100, a second PCB board 200, and a third PCB board 300 stacked sequentially from top to bottom. The upper surface of the first PCB board 100 is provided with a plurality of triangular patches 110, which are identical in size and structure and rotationally symmetrical about the center of the first PCB board 100. The lower surface of the first PCB board 100 is provided with a plurality of delay lines 120 corresponding one-to-one with the plurality of triangular patches 110. Each triangular patch 110 has a... A first metal through-hole 130 passes through the first PCB board 100 and extends to the delay line 120. A first ground copper layer 210 is provided on the upper surface of the second PCB board 200. A cross-shaped slot 220 is opened in the center of the first ground copper layer 210. A wire copper layer 310 is provided on the upper surface of the third PCB board 300. A second ground copper layer 320 is provided on the lower surface of the third PCB board 300. A power supply hole 330 is opened in the wire copper layer 310. The power supply hole 330 passes through the third PCB board 300 and extends to the second ground copper layer 320.

[0036] According to an embodiment of the present invention, a circularly polarized complementary antenna for low-Earth orbit satellite communication is provided. Multiple triangular patches 110 disposed on the upper surface of a first PCB board 100 constitute an electric dipole. The multiple triangular patches 110 are identical in size and structure and are rotationally symmetrical about the center of the first PCB board 100. A first ground copper layer 210 is disposed on the upper surface of a second PCB board 200. A cross-shaped slot 220 is formed in the center of the first ground copper layer 210. The cross-shaped slot 220 is rotationally symmetrical about the center of the first ground copper layer 210. The electric dipole is fed by the cross-shaped slot 220 of the first ground copper layer 210. Multiple triangular patches 110 disposed on the lower surface of the first PCB board 100 constitute an electric dipole. Each triangular patch 110 corresponds to a plurality of delay lines 120, and a first metal via 130 and a first ground copper layer 210 formed on each triangular patch 110 constitute a magnetic dipole. The relative phase of the magnetic dipole and the electric dipole is adjusted by the delay lines 120. A wired copper layer 310 is provided on the upper surface of the third PCB board 300, and a second ground copper layer 320 is provided on the lower surface of the third PCB board 300. A power feeding hole 330 is provided in the wired copper layer 310. The power feeding hole 330 passes through the third PCB board 300 and extends to the second ground copper layer 320. The wired copper layer 310 provides energy coupling power to the cross-shaped slot 220 in the first ground copper layer 210. This invention employs a triangular patch antenna 110 as an electric dipole antenna and a slot antenna as a magnetic dipole antenna. Since both the electric and magnetic dipoles utilize rotationally symmetric structures, circular polarization is achieved. The electric and magnetic dipoles share a cross-shaped slot 220 as a feed source, forming a complementary antenna combination. This achieves low cross-polarization levels, stable gain, and low backfire levels, while also extending the antenna's operating bandwidth. Furthermore, a delay line 120 is added to the dipole antenna to adjust the relative phase, ensuring that the feed phases of the electric and magnetic dipoles are synchronized, maintaining a low axial ratio under low elevation conditions. Additionally, phase modulation is achieved through the use of the cross-shaped slot 220 and the copper layer 310 for feeding, thereby improving the stability and reliability of low-Earth orbit satellite communication.

[0037] It should be noted that, as Figure 1 As shown, the first PCB board 100, the second PCB board 200 and the third PCB board 300 are the same size and all use square dielectric substrates.

[0038] In one embodiment, the lengths of the first PCB board 100, the second PCB board 200, and the third PCB board 300 are all 8.5 mm, and the widths of the first PCB board 100, the second PCB board 200, and the third PCB board 300 are all 8.5 mm.

[0039] It is understandable that, such as Figure 3As shown, one end of each delay line 120 is connected to the first metal via 130, and the other end is connected to the first ground copper layer 210.

[0040] In one embodiment, the triangular patch 110 is a metal patch, and the first metal through hole 130 and the power supply hole 330 are both metallized vias. The diameter of the first metal through hole 130 is 0.30 mm.

[0041] Reference Figure 1 In some embodiments of the present invention, a first adhesive layer 400 disposed between a first PCB board 100 and a second PCB board 200, and a second adhesive layer 500 disposed between the second PCB board 200 and a third PCB board 300 are further included. The thickness of the first adhesive layer 400 is greater than the thickness of the second adhesive layer 500, and the dielectric constant of the first adhesive layer 400 and the dielectric constant of the second adhesive layer 500 are the same. It is understood that the first adhesive layer 400 disposed between the first PCB board 100 and the second PCB board 200 serves as a delay line 120 layer, and its surface is not covered with metal. Similarly, the second adhesive layer 500 disposed between the second PCB board 200 and the third PCB board 300 serves as a transition layer, and its surface is not covered with metal.

[0042] Furthermore, such as Figure 1 As shown, a first PCB board 100, a first adhesive layer 400, a second PCB board 200, a second adhesive layer 500, and a third PCB board 300, stacked sequentially from top to bottom, constitute an antenna assembly. Furthermore, the first adhesive layer 400 and the second adhesive layer 500 are the same size as the first PCB board 100, the second PCB board 200, and the third PCB board 300. The substrates of both the first adhesive layer 400 and the second adhesive layer 500 are square PP (polypropylene) boards, and the length and width of both the first adhesive layer 400 and the second adhesive layer 500 are 8.5 mm.

[0043] In one embodiment, the thickness of the first adhesive layer 400 is 0.2 mm, the thickness of the second adhesive layer 500 is 0.1 mm, and the dielectric constant of both the first adhesive layer 400 and the second adhesive layer 500 is 3.52.

[0044] Reference Figure 3 In some embodiments of the present invention, there are four delay lines 120, and all four delay lines 120 are S-shaped. It should be noted that the four delay lines 120 in these embodiments are all S-shaped, and all four delay lines 120 are microstrip delay lines 120. The S-shaped delay lines 120 allow for adjustment of the relative phase between the magnetic dipole and the electric dipole to maintain a consistent 90°, thereby achieving a low axial ratio under low elevation angle conditions.

[0045] Reference Figure 2 and Figure 4 In some embodiments of the present invention, the number of triangular patches 110 is four. The two rectangular gaps 141 between the four triangular patches 110 intersect to form a cross-shaped gap 140, and the geometric center of the cross-shaped gap 140 coincides with the geometric center of the cross-shaped slot 220. It should be noted that the electric dipole is composed of four triangular patches 110, and the vertices of the four triangular patches 110 face the center of the square substrate. Adjacent patches form right angles. Therefore, the two rectangular gaps 141 between the four triangular patches 110 intersect to form a cross-shaped gap 140. The geometric center of the cross-shaped gap 140 coincides with the center of the first PCB board 100, forming a rotationally symmetrical structure, and coincides with the geometric center of the cross-shaped slot 220 of the first ground copper layer 210. Thus, the cross-shaped slot 220 feeds the electric dipole composed of the four triangular patches 110.

[0046] In one embodiment, the number of first metal through holes 130 is the same as the number of triangular patches 110, that is, each triangular patch 110 has a first metal through hole 130, and a total of 4 first metal through holes 130 are provided on the first PCB board 100.

[0047] Reference Figure 2 and Figure 4 In some embodiments of the present invention, the cross-shaped slot 220 includes two intersecting rectangular slots 221. The two rectangular slots 221 have the same length and width, and the projection of the rectangular slots 221 on the upper surface of the first PCB board 100 partially coincides with the rectangular gap 141. It should be noted that two rectangular slots 221 are formed in the first ground copper layer 210, and the cross-shaped slot 220 is formed by the two intersecting rectangular slots 221. The two rectangular slots 221 have the same length and width, with a length of 4.2 mm and a width of 0.4 mm. Further, the projection of the rectangular slots 221 on the upper surface of the first PCB board 100 partially coincides with the rectangular gap 141, that is, the projection of the cross-shaped slot 220 on the upper surface of the first PCB board 100 partially coincides with the cross-shaped gap 140.

[0048] Reference Figure 5In some embodiments of the present invention, the strip copper layer 310 includes a first microstrip line 311 and a second microstrip line 312 vertically connected on the plane of the third PCB board 300. The length of the first microstrip line 311 is greater than the length of the second microstrip line 312, and the width of the first microstrip line 311 is less than the width of the second microstrip line 312. A convex structure 313 is formed at the end of the second microstrip line 312. It can be understood that the strip copper layer 310, as a strip line, performs energy coupling to the cross-shaped gap 220 in the first ground copper layer 210. Specifically, it can be controlled by a T-shaped feed line composed of the first microstrip line 311 and the second microstrip line 312 vertically connected on the plane of the third PCB board 300. The wider the first microstrip line 311 and the second microstrip line 312, the greater the energy. The greater the length difference between the first microstrip line 311 and the second microstrip line 312, the greater the phase difference. In one embodiment, the first microstrip line 311 has a length of 5.2 mm and a width of 0.9 mm, the second microstrip line 312 has a length of 1.05 mm and a width of 1.3 mm, and the convex structure 313 at the end of the second microstrip line 312 has a width of 0.8 mm. It should be understood that this embodiment of the invention uses a cross-shaped slot 220 and a T-shaped feeder for phase modulation. By adjusting the power distribution and phase difference of the T-shaped feeder, different energy ratios and phase ratios are set to achieve switching between multiple polarization modes. Specifically, a left-hand circular polarization can be formed by setting the energy distribution to 1:1 and the phase difference to 90 degrees; a right-hand circular polarization can be formed by setting the energy distribution to 1:1 and the phase difference to -90 degrees.

[0049] Reference Figure 5 and Figure 6 In some embodiments of the present invention, a feed hole 330 is disposed at one end of the first microstrip line 311, and a circular non-metallic region 321 is disposed on the second ground copper layer 320. The center of the circular non-metallic region 321 coincides with the center of the feed hole 330, and the diameter of the circular non-metallic region 321 is larger than the diameter of the feed hole 330. It should be noted that the feed hole 330 opened on the strip copper layer 310 can specifically be opened at one end of the first microstrip line 311, and extend through the third PCB board 300 to the second ground copper layer 320. Then, a circular non-metallic region 321 can be processed on the second ground copper layer 320. This circular non-metallic region 321 is a non-metallic region surrounding the feed hole 330, thereby maintaining electrical isolation between the feed hole 330 and the second ground copper layer 320.

[0050] Reference Figure 2 and Figure 3In some embodiments of the present invention, a plurality of corresponding second metal through-holes 600 are formed on the first PCB board 100 and the first adhesive layer 400. The plurality of second metal through-holes 600 are respectively arranged circumferentially along the edges of the first PCB board 100 and the first adhesive layer 400, and the second metal through-holes 600 pass through the first PCB board 100 and the first adhesive layer 400 and extend to the first ground copper layer 210. It should be noted that the second metal through-holes 600 penetrate downward from the first PCB board 100 and the first adhesive layer 400 until they reach the first ground copper layer 210 and connect.

[0051] In one embodiment, the diameter of the second metal through hole 600 is larger than the diameter of the first metal through hole 130. Both the second metal through hole 600 and the first metal through hole 130 are metallized vias, and the diameter of the second metal through hole 600 is 0.60 mm.

[0052] Reference Figure 5 and Figure 6 In some embodiments of the present invention, a plurality of corresponding third metal through-holes 700 are formed in the second PCB board 200, the third PCB board 300, and the second adhesive layer 500. The plurality of third metal through-holes 700 are respectively arranged circumferentially along the edges of the second PCB board 200, the third PCB board 300, and the second adhesive layer 500, and the third metal through-holes 700 pass through the second PCB board 200, the third PCB board 300, and the second adhesive layer 500 and extend to the second ground copper layer 320. It should be noted that the third metal through-holes 700 penetrate downwards from the second PCB board 200 through the second adhesive layer 500 and the third PCB board 300 until they reach and connect with the second ground copper layer 320.

[0053] In one embodiment, the diameter of the third metal via 700 is smaller than the diameter of the second metal via 600, and the third metal via 700 is a metallized via.

[0054] It is understood that in the embodiments of the present invention, the plurality of second metal through holes 600 and the plurality of third metal through holes 700 correspond one-to-one, that is, the number of second metal through holes 600 and the number of third metal through holes 700 are the same, and the corresponding second metal through holes 600 and third metal through holes 700 are opened on the same axis.

[0055] In one embodiment, the number of second metal through holes 600 and the number of third metal through holes 700 are both 32.

[0056] Reference Figure 1In some embodiments of the present invention, the thickness of the first PCB board 100 is greater than the thickness of the second PCB board 200, the thickness of the second PCB board 200 is the same as the thickness of the third PCB board 300, the dielectric constant of the first PCB board 100 is greater than the dielectric constant of the third PCB board 300, and the dielectric constant of the second PCB board 200 is greater than the dielectric constant of the first PCB board 100. It should be noted that the thickness of the first PCB board 100 is 1.026 mm, the thickness of the second PCB board 200 is 0.168 mm, and the thickness of the third PCB board 300 is 0.168 mm. Further, the dielectric constant of the first PCB board 100 is 3.55, the dielectric constant of the second PCB board 200 is 3.66, and the dielectric constant of the third PCB board 300 is 2.94.

[0057] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A circularly polarized complementary antenna applied to low earth orbit satellite communication, characterized in that, The first PCB plate, the second PCB plate and the third PCB plate are sequentially stacked from top to bottom. The upper surface of the first PCB plate is provided with a plurality of triangular patches which are rotationally symmetrical about the center of the first PCB plate, and the lower surface of the first PCB plate is provided with a plurality of delay lines corresponding to the plurality of triangular patches. The upper surface of the second PCB plate is provided with a first ground copper layer, and the center of the first ground copper layer is provided with a cross-shaped gap. The upper surface of the third PCB plate is provided with a strip-line copper layer, and the lower surface of the third PCB plate is provided with a second ground copper layer, the strip-line copper layer is provided with a feed hole, the feed hole extends to the second ground copper layer through the third PCB plate, the strip-line copper layer includes a first microstrip line and a second microstrip line which are connected vertically on the plane of the third PCB plate, the length of the first microstrip line is greater than the length of the second microstrip line, the width of the first microstrip line is less than the width of the second microstrip line, and the end of the second microstrip line is formed with a convex structure.

2. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 1, wherein, The first adhesive layer is provided between the first PCB plate and the second PCB plate, and the second adhesive layer is provided between the second PCB plate and the third PCB plate, the thickness of the first adhesive layer is greater than the thickness of the second adhesive layer, and the dielectric constant of the first adhesive layer is the same as the dielectric constant of the second adhesive layer.

3. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 1, wherein, The number of the delay lines is four, and the shape of the four delay lines is S-shaped.

4. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 1, wherein, The number of the triangular patches is four, and the two rectangular gaps between the four triangular patches intersect to form a cross-shaped gap, and the geometric center of the cross-shaped gap coincides with the geometric center of the cross-shaped gap.

5. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 4, wherein, The cross-shaped gap includes two rectangular gaps which are cross-shaped, the length and width of the two rectangular gaps are the same, and the projection of the rectangular gap on the upper surface of the first PCB plate partially coincides with the rectangular gap.

6. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 1, wherein, The feed hole is arranged at one end of the first microstrip line, the second ground copper layer is provided with a circular non-metallic area, the center of the circular non-metallic area coincides with the center of the feed hole, and the diameter of the circular non-metallic area is greater than the diameter of the feed hole.

7. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 2, wherein, The first PCB plate and the first adhesive layer are provided with a plurality of second metal through holes corresponding to each other, a plurality of second metal through holes are arranged along the edge of the first PCB plate and the first adhesive layer in a circumferential direction, and the second metal through hole extends to the first ground copper layer through the first PCB plate and the first adhesive layer.

8. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 2, wherein, The second PCB plate, the third PCB plate and the second adhesive layer are provided with a plurality of third metal through holes corresponding to each other, the third metal through holes are arranged along the edges of the second PCB plate, the third PCB plate and the second adhesive layer in a circumferential direction and respectively, and the third metal through holes pass through the second PCB plate, the third PCB plate and the second adhesive layer and extend to the second ground copper layer.

9. The circularly polarized complementary antenna for low earth orbit satellite communications of claim 1, wherein, The thickness of the first PCB plate is greater than the thickness of the second PCB plate, the thickness of the second PCB plate is the same as the thickness of the third PCB plate, the dielectric constant of the first PCB plate is greater than the dielectric constant of the third PCB plate, and the dielectric constant of the second PCB plate is greater than the dielectric constant of the first PCB plate.

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