Circularly polarized complementary antenna applied to low-orbit satellite communication

Abstract

The invention discloses a circularly polarized complementary antenna applied to low-orbit satellite communication, which comprises a first PCB, a second PCB and a third PCB which are sequentially stacked from top to bottom, a plurality of triangular patches are arranged on the upper surface of the first PCB, the triangular patches are the same in size and structure and are rotationally symmetrical about the center of the first PCB, and the third PCB is arranged on the lower surface of the first PCB. A plurality of triangular patches are arranged on the upper surface of the first PCB, a plurality of delay lines corresponding to the triangular patches one to one are arranged on the lower surface of the first PCB, a first metal through hole is formed in each triangular patch, the first metal through holes penetrate through the first PCB and extend to the delay lines, a first ground copper layer is arranged on the upper surface of the second PCB, a cross-shaped gap is formed in the center of the first ground copper layer, and a second ground copper layer is arranged in the cross-shaped gap. A strip line copper layer is arranged on the upper surface of the third PCB, a second ground copper layer is arranged on the lower surface of the third PCB, a feed hole is formed in the strip line copper layer, and the feed hole penetrates through the third PCB and extends to the second ground copper layer. According to the invention, the working bandwidth of the antenna is expanded, and the low axial ratio is kept under the condition of low elevation angle.

Description

Technical Field

[0001] The present invention relates to the technical field of circularly polarized antennas, and in particular to a circularly polarized complementary antenna used in low-orbit satellite communications. Background Art

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

[0003] In existing satellite communication technologies, phased arrays are often used for beamforming to achieve satellite tracking with radiated beams. However, because the overall performance of a phased array depends on the coordinated operation of numerous antenna elements, when used in low-elevation angle scenarios, the antenna elements are prone to problems such as excessive axial ratio and insufficient gain, resulting in significant performance degradation and making it difficult to ensure stable and efficient satellite communications. Summary of the Invention

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

[0005] An embodiment of the present invention provides a circularly polarized complementary antenna for low-orbit satellite communications, comprising a first PCB board, a second PCB board, and a third PCB board stacked sequentially from top to bottom; a plurality of triangular patches are provided on the upper surface of the first PCB board, the plurality of triangular patches having the same size and structure and being rotationally symmetric about the center of the first PCB board; a plurality of delay lines corresponding one-to-one to the plurality of triangular patches are provided on the lower surface of the first PCB board, each of the triangular patches being provided with a first metal through-hole, the first metal through-hole passing through the first PCB board and extending to the delay line; a first ground copper layer is provided on the upper surface of the second PCB board, a cross-shaped slit is provided at the center of the first ground copper layer; a stripline copper layer is provided on the upper surface of the third PCB board, and a second ground copper layer is provided on the lower surface of the third PCB board, the stripline copper layer being provided with a feeding hole, the feeding hole passing through the third PCB board and extending to the second ground copper layer.

[0006] A circularly polarized complementary antenna for low-orbit satellite communications provided in accordance with an embodiment of the present invention has at least the following beneficial effects: The embodiment of the present invention uses a triangular patch antenna as an electric dipole antenna and a slot antenna as a magnetic dipole antenna. Since both the electric dipole and the magnetic dipole adopt a rotationally symmetric structure, the circular polarization characteristic of the antenna is realized. The electric dipole and the magnetic dipole use a cross-shaped slot as a feed source to form a combination of complementary antennas, thereby achieving a low cross-polarization level, stable gain and low backscatter level, and expanding the working bandwidth of the antenna. In addition, a delay line is added to the dipole antenna to adjust the relative phase of the antenna, so that the feeding phase of the electric dipole and the magnetic dipole are consistent, thereby maintaining a low axial ratio under low elevation angle conditions. In addition, by using a cross-shaped slot and a stripline copper layer to feed phase modulation, the antenna forms circularly polarized radiation when the phase difference is equal to 90 degrees, thereby improving the stability and reliability of low-orbit satellite communications.

[0007] According to some embodiments of the present invention, the first adhesive layer is further provided between the first PCB board and the second PCB board, and the second adhesive layer is provided between the second PCB board and the third PCB board. 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.

[0008] According to some embodiments of the present invention, the number of the delay lines is four, and the shapes of the four delay lines are all S-shaped.

[0009] According to some embodiments of the present invention, the number of the triangular patches is 4, the two rectangular gaps between the 4 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 slit.

[0010] According to some embodiments of the present invention, the cross-shaped gap includes two cross-arranged rectangular gaps, the two rectangular gaps have the same length and width, and the projection of the rectangular gap on the upper surface of the first PCB board partially overlaps with the rectangular gap.

[0011] According to some embodiments of the present invention, the stripline copper layer includes a first microstrip line and a second microstrip line vertically connected on the plane of the third PCB board, 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.

[0012] According to some embodiments of the present invention, the feeding hole is arranged at one end of the first microstrip line, and 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 feeding hole, and the diameter of the circular non-metallic area is greater than the diameter of the feeding hole.

[0013] According to some embodiments of the present invention, the first PCB board and the first adhesive layer are provided with a plurality of second metal through-holes corresponding to each other. The plurality of second metal through-holes are respectively arranged at intervals along the circumferential 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.

[0014] 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 third metal through-holes corresponding to each other. The plurality of third metal through-holes are circumferentially spaced along the edges of the second PCB board, the third PCB board, and the second adhesive layer, respectively. 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.

[0015] 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 is the same as the thickness of the third PCB board, 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.

[0016] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation to the technical solution of the present invention.

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 1 is a schematic diagram of the overall structure of a circularly polarized complementary antenna for low-orbit satellite communications provided by an embodiment of the present invention; Figure 2 is a top view of a first PCB board in an embodiment of the present invention; Figure 3 is a bottom view of the first PCB board in an embodiment of the present invention; Figure 4 is a top view of the second PCB board in an embodiment of the present invention; Figure 5 is a top view of a third PCB board in an embodiment of the present invention; Figure 6FIG. 4 is a bottom view of the third PCB board in the embodiment of the present invention.

[0019] Figure 1: First PCB board 100, triangular patch 110, delay line 120, first metal through hole 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, stripline copper layer 310, first microstrip line 311, second microstrip line 312, convex structure 313, second ground copper layer 320, circular non-metallic area 321, feed hole 330, first adhesive layer 400, second adhesive layer 500, second metal through hole 600, third metal through hole 700. DETAILED DESCRIPTION

[0020] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but they should not be understood as limiting the scope of protection of the present invention.

[0021] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" 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 plural items. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, or implicitly indicating the quantity of the indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] It should be noted that the terms "dispose," "install," and "connect" in the embodiments of the present invention should be interpreted broadly. Those skilled in the art can reasonably determine the specific meanings of these terms in the embodiments of the present invention based on the specific content of the technical solution. For example, the term "connect" can refer to mechanical connection, electrical connection, or communication; it can be direct connection or indirect connection through an intermediary.

[0023] 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.

[0024] During low-orbit satellite communications, the relative position of the satellite and the antenna will change, so the communication system must also have the function of "chasing stars", that is, the radiation beam changes with the change of the satellite position.

[0025] In existing satellite communication technologies, phased arrays are often used for beamforming to achieve satellite tracking with radiated beams. However, because the overall performance of a phased array depends on the coordinated operation of numerous antenna elements, when used in low-elevation angle scenarios, the antenna elements are prone to problems such as excessive axial ratio and insufficient gain, resulting in significant performance degradation and making it difficult to ensure stable and efficient satellite communications.

[0026] Based on this, an embodiment of the present invention provides a circularly polarized complementary antenna for low-orbit satellite communications, which can not only expand the working bandwidth of the antenna, but also maintain a low axial ratio under low elevation angle conditions, thereby improving the stability and reliability of low-orbit satellite communications.

[0027] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0028] Reference Figures 1 to 6 The circularly polarized complementary antenna for low-orbit satellite communications 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 in sequence from top to bottom. The upper surface of the first PCB board 100 is provided with a plurality of triangular patches 110. The plurality of triangular patches 110 have the same size and structure and are rotationally symmetric 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 to the plurality of triangular patches 110. Each triangular patch 110 has a A first metal via 130 is provided, which 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, and a cross-shaped slit 220 is defined in the center of the first ground copper layer 210. A stripline 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 feed hole 330 is defined in the stripline copper layer 310, and the feed hole 330 passes through the third PCB board 300 and extends to the second ground copper layer 320.

[0029] According to an embodiment of the present invention, a circularly polarized complementary antenna for low-orbit satellite communications is provided. A plurality of triangular patches 110 arranged on the upper surface of a first PCB board 100 constitute an electric dipole. The plurality of triangular patches 110 have the same size and structure and are rotationally symmetric about the center of the first PCB board 100. A first ground copper layer 210 is provided on the upper surface of a second PCB board 200. A cross-shaped slot 220 is opened at the center of the first ground copper layer 210. The cross-shaped slot 220 is rotationally symmetric 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 delay lines 120 corresponding to each triangular patch 110, a first metal via 130 defined in each triangular patch 110, and a first ground copper layer 210 form a magnetic dipole. The relative phase of the magnetic dipole and the electric dipole is adjusted by the delay line 120. A stripline 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. The stripline copper layer 310 has a feeding hole 330 defined therein. The feeding hole 330 passes through the third PCB board 300 and extends to the second ground copper layer 320. The stripline copper layer 310 couples energy to the cross-shaped slot 220 in the first ground copper layer 210. The embodiment of the present invention uses a triangular patch 110 antenna as an electric dipole antenna and a slot antenna as a magnetic dipole antenna. Since both the electric dipole and the magnetic dipole adopt a rotationally symmetric structure, the circular polarization characteristics of the antenna are realized. The electric dipole and the magnetic dipole use a cross-shaped slot 220 as a feed source to form a combination of complementary antennas, thereby achieving a low cross-polarization level, stable gain and low backscatter level, and expanding the working bandwidth of the antenna. In addition, a delay line 120 is added to the dipole antenna to adjust the relative phase of the antenna, so that the feeding phase of the electric dipole and the magnetic dipole are consistent, thereby maintaining a low axial ratio under low elevation angle conditions. In addition, by using the cross-shaped slot 220 and the stripline copper layer 310 for feeding, phase modulation is formed, thereby improving the stability and reliability of low-orbit satellite communications.

[0030] It should be noted that if Figure 1 As shown, the first PCB board 100 , the second PCB board 200 and the third PCB board 300 have the same size and all adopt square dielectric substrates.

[0031] 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.

[0032] It is understandable that if 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 .

[0033] In one embodiment, the triangular patch 110 is a metal patch, the first metal through hole 130 and the feeding hole 330 are both metalized vias, and the diameter of the first metal through hole 130 is 0.30 mm.

[0034] Reference Figure 1 In some embodiments of the present invention, a first adhesive layer 400 is disposed between the first PCB board 100 and the second PCB board 200, and a second adhesive layer 500 is disposed between the second PCB board 200 and the third PCB board 300. The thickness of the first adhesive layer 400 is greater than that of the second adhesive layer 500, and the dielectric constant of the first adhesive layer 400 is the same as that of the second adhesive layer 500. It is understood that the first adhesive layer 400 disposed between the first PCB board 100 and the second PCB board 200 serves as the delay line 120 layer and has no metal coating on its surface. Furthermore, the second adhesive layer 500 disposed between the second PCB board 200 and the third PCB board 300 serves as a transition layer and has no metal coating on its surface.

[0035] Furthermore, if Figure 1 As shown, the first PCB board 100, first adhesive layer 400, second PCB board 200, second adhesive layer 500, and third PCB board 300, stacked in descending order from top to bottom, form an integral antenna. Furthermore, the first adhesive layer 400 and second adhesive layer 500 are of the same size as the first PCB board 100, second PCB board 200, and third PCB board 300. The substrates for the first adhesive layer 400 and second adhesive layer 500 are both square PP boards (polypropylene boards), and the length and width of the first adhesive layer 400 and second adhesive layer 500 are both 8.5 mm.

[0036] 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 constants of the first adhesive layer 400 and the second adhesive layer 500 are both 3.52.

[0037] Reference Figure 3 In some embodiments of the present invention, the number of delay lines 120 is four, and the shape of the four delay lines 120 is all S-shaped. It should be noted that the shape of the four delay lines 120 in the embodiment of the present invention is all S-shaped, and all four delay lines 120 are microstrip delay lines 120. The S-shaped delay lines 120 can be used to adjust the relative phase of the magnetic dipole and the electric dipole to remain consistent at 90°, thereby achieving a low axial ratio under low elevation angle conditions.

[0038] Reference Figure 2 and Figure 4 In some embodiments of the present invention, the number of triangular patches 110 is four, and 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 gap 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, and right angles are formed between adjacent patches. Therefore, 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 center of the first PCB board 100, forming a rotationally symmetrical structure. It also coincides with the geometric center of the cross-shaped gap 220 of the first ground copper layer 210, and the cross-shaped gap 220 then feeds the electric dipole composed of the four triangular patches 110.

[0039] In one embodiment, the number of the first metal through holes 130 is the same as the number of the triangular patches 110 , that is, each triangular patch 110 is provided with a first metal through hole 130 , and a total of four first metal through holes 130 are provided on the first PCB board 100 .

[0040] Reference Figure 2 and Figure 4 In some embodiments of the present invention, the cross-shaped gap 220 includes two rectangular gaps 221 arranged in a cross pattern. The two rectangular gaps 221 have the same length and width, and the projection of the rectangular gap 221 on the upper surface of the first PCB board 100 partially overlaps with the rectangular gap 141. It should be noted that two rectangular gaps 221 are provided in the first ground copper layer 210, forming the cross-shaped gap 220 by the two intersecting rectangular gaps 221. The two rectangular gaps 221 have the same length and width, 4.2 mm in length and 0.4 mm in width. Furthermore, the projection of the rectangular gap 221 on the upper surface of the first PCB board 100 partially overlaps with the rectangular gap 141, that is, the projection of the cross-shaped gap 220 on the upper surface of the first PCB board 100 partially overlaps with the cross-shaped gap 140.

[0041] Reference Figure 5In some embodiments of the present invention, the stripline copper layer 310 includes a first microstrip line 311 and a second microstrip line 312 connected perpendicularly on the plane of the third PCB board 300. The length of the first microstrip line 311 is greater than that of the second microstrip line 312, and the width of the first microstrip line 311 is less than that of the second microstrip line 312. A convex structure 313 is formed at the end of the second microstrip line 312. It is understood that the stripline copper layer 310 acts as a stripline to couple energy to the cross-shaped slot 220 in the first ground copper layer 210. Specifically, the T-shaped feed line formed by the first and second microstrip lines 311, 312 connected perpendicularly on the plane of the third PCB board 300 can control the magnitude and phase of the coupled energy. The wider the first and second microstrip lines 311, 312, the greater the energy, and the greater the length difference between the first and second microstrip lines 311, 312, the greater the phase difference. In one embodiment, the length of the first microstrip line 311 is 5.2 mm, the width of the first microstrip line 311 is 0.9 mm, the length of the second microstrip line 312 is 1.05 mm, the width of the second microstrip line 312 is 1.3 mm, and the width of the convex structure 313 at the end of the second microstrip line 312 is 0.8 mm. It should be understood that the embodiment of the present invention uses the cross-shaped gap 220 and the T-shaped feed line for phase modulation. By adjusting the power distribution and phase difference of the T-shaped feed line, different energy ratios and phase ratios are set to achieve switching of multiple polarization modes. Specifically, by setting the energy distribution to 1:1 and the phase difference to 90 degrees, left-hand circular polarization can be formed; by setting the energy distribution to 1:1 and the phase difference to -90 degrees, right-hand circular polarization can be formed.

[0042] Reference Figure 5 and Figure 6 In some embodiments of the present invention, a feed hole 330 is provided at one end of the first microstrip line 311, and a circular non-metallic area 321 is provided on the second ground copper layer 320. The center of the circular non-metallic area 321 coincides with the center of the feed hole 330, and the diameter of the circular non-metallic area 321 is larger than the diameter of the feed hole 330. It should be noted that the feed hole 330 provided on the stripline copper layer 310 can be provided at one end of the first microstrip line 311, pass through the third PCB board 300, and extend to the second ground copper layer 320. Furthermore, a circular non-metallic area 321 can be processed on the second ground copper layer 320. The circular non-metallic area 321 is a non-metallic area surrounding the feed hole 330, thereby maintaining electrical isolation between the feed hole 330 and the second ground copper layer 320.

[0043] Reference Figure 2 and Figure 3In some embodiments of the present invention, the first PCB board 100 and the first adhesive layer 400 are provided with a plurality of second metal vias 600 corresponding to each other. The plurality of second metal vias 600 are spaced circumferentially along the edges of the first PCB board 100 and the first adhesive layer 400. The second metal vias 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 vias 600 extend downward from the first PCB board 100 through the first PCB board 100 and the first adhesive layer 400 until they connect with the first ground copper layer 210.

[0044] In one embodiment, the diameter of the second metal via 600 is greater than the diameter of the first metal via 130 . Both the second metal via 600 and the first metal via 130 are metallized vias. The diameter of the second metal via 600 is 0.60 mm.

[0045] Reference Figure 5 and Figure 6 In some embodiments of the present invention, the second PCB board 200, the third PCB board 300, and the second adhesive layer 500 are provided with a plurality of third metal vias 700, each corresponding to the other. The plurality of third metal vias 700 are spaced circumferentially along the edges of the second PCB board 200, the third PCB board 300, and the second adhesive layer 500, respectively. The third metal vias 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 vias 700 extend downward from the second PCB board 200 through the second adhesive layer 500 and the third PCB board 300 until they connect with the second ground copper layer 320.

[0046] 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.

[0047] It can be understood that the multiple second metal through-holes 600 and the multiple third metal through-holes 700 in the embodiment of the present invention correspond one to one, that is, the number of the second metal through-holes 600 is the same as the number of the third metal through-holes 700, and the corresponding second metal through-holes 600 and the third metal through-holes 700 are opened on the same axis.

[0048] In one embodiment, the number of the second metal vias 600 and the number of the third metal vias 700 are both 32.

[0049] Reference Figure 1In some embodiments of the present invention, the thickness of the first PCB board 100 is greater than that of the second PCB board 200, the thickness of the second PCB board 200 is the same as that of the third PCB board 300, the dielectric constant of the first PCB board 100 is greater than that of the third PCB board 300, and the dielectric constant of the second PCB board 200 is greater than that 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. Furthermore, 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.

[0050] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the scope of the present invention.

Claims

1. A circularly polarized complementary antenna for low-orbit satellite communications, characterized in that: The first PCB board, the second PCB board and the third PCB board are stacked in order from top to bottom; A plurality of triangular patches are provided on the upper surface of the first PCB board. The plurality of triangular patches are of the same size and structure and are rotationally symmetrical about the center of the first PCB board. A plurality of delay lines are provided on the lower surface of the first PCB board, corresponding one-to-one to the plurality of triangular patches. A first metal through-hole is formed on each of the triangular patches. The first metal through-hole passes through the first PCB board and extends to the delay line. A first ground copper layer is provided on the upper surface of the second PCB board, and a cross-shaped gap is opened in the center of the first ground copper layer; A strip copper layer is provided on the upper surface of the third PCB board, and a second ground copper layer is provided on the lower surface of the third PCB board. A feeding hole is opened in the strip copper layer, and the feeding hole passes through the third PCB board and extends to the second ground copper layer.

2. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 1, wherein: It also includes a first adhesive layer arranged between the first PCB board and the second PCB board, and a second adhesive layer arranged between the second PCB board and the third PCB board. 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-orbit satellite communications according to claim 1, wherein: The number of the delay lines is 4, and the shapes of the 4 delay lines are all S-shaped.

4. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 1, wherein: The number of the triangular patches is 4, and the two rectangular gaps between the 4 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 slit.

5. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 4, characterized in that: The cross-shaped gap includes two rectangular gaps arranged crosswise, the two rectangular gaps have the same length and width, and the projection of the rectangular gap on the upper surface of the first PCB board partially overlaps with the rectangular gap.

6. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 1, wherein: The stripline copper layer includes a first microstrip line and a second microstrip line vertically connected on the plane of the third PCB board, 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.

7. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 6, characterized in that: The feeding hole is arranged at one end of the first microstrip line, and 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 feeding hole, and the diameter of the circular non-metallic area is greater than the diameter of the feeding hole.

8. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 2, wherein: The first PCB board and the first adhesive layer are provided with a plurality of second metal through holes corresponding to each other. The plurality of second metal through holes are respectively arranged at intervals along the circumferential edges of the first PCB board and the first adhesive layer. The second metal through holes pass through the first PCB board and the first adhesive layer and extend to the first ground copper layer.

9. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 2, wherein: The second PCB board, the third PCB board, and the second adhesive layer are provided with a plurality of third metal through-holes corresponding to each other. The plurality of third metal through-holes are circumferentially spaced along the edges of the second PCB board, the third PCB board, and the second adhesive layer, respectively. 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.

10. The circularly polarized complementary antenna for low-orbit satellite communications according to claim 1, wherein: The thickness of the first PCB board is greater than that of the second PCB board, the thickness of the second PCB board is the same as that of the third PCB board, the dielectric constant of the first PCB board is greater than that of the third PCB board, and the dielectric constant of the second PCB board is greater than that of the first PCB board.

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