Ka-band circularly polarized antenna

Abstract

The application discloses a Ka-band circularly polarized antenna and belongs to the technical field of satellite communication, which is composed of a metal back plate, a dielectric layer, a feed structure, a SIW structure, a radiation patch and a parasitic patch. Through the signal input of a double-port phase difference of 90 DEG and a coaxial feed mode, the Ka-band circular polarization is realized, and the high width of the antenna radiation axial ratio is realized by using a special defect structure. The antenna can realize the output of a circularly polarized signal of 26.38GHz-27.82GHz, and the axial ratio width of the antenna below-3dB is 117 DEG-152 DEG.

Description

Technical Field

[0001] This invention designs a novel Ka-band circularly polarized antenna. The antenna operates in the Ka band and has excellent S-parameters and axial ratio parameters, belonging to fields such as satellite communication. Background Technology

[0002] Millimeter-wave electromagnetic waves possess advantages such as high resolution, clear imaging, strong penetration, wide bandwidth, and large transmission capacity, making millimeter-wave antennas a research hotspot. As an indispensable front-end device in millimeter-wave communication systems, antennas of various types have been extensively studied. The Ka-band, with a frequency range of 26.5-40 GHz, is primarily used in satellite communications. However, in satellite communication technology, signals are affected by long propagation paths and complex path conditions, thus impacting the accuracy of signal reception. For example, atmospheric refraction and reflection can cause deflection of signal polarization, leading to polarization mismatch; rain and snow result in significant signal propagation loss, leading to poor communication quality; and the Earth's magnetic field at the poles can cause the Faraday effect. Circularly polarized signals can solve the polarization mismatch problem, experience less loss in rain and snow, and are unaffected by the Faraday effect; therefore, circularly polarized antennas are widely used in satellite communications. In satellite communication technology, due to the long communication links and high transmission loss, the antenna devices used for receiving and transmitting need to have high energy radiation performance in order to meet the requirements of low power consumption antenna element structure. Therefore, antenna elements with high energy radiation performance have practical research significance. Summary of the Invention

[0003] This invention addresses the antenna radiation performance requirements of satellite communication systems by designing a circularly polarized antenna structure with dual-port coaxial feed, double-layer radiating patches, and parasitic patches. This structure meets the radiation performance requirements of satellite communication systems. The designed antenna features a simple structure and low profile.

[0004] To achieve the functional requirements of a satellite communication system, this invention specifically employs the following technical solution:

[0005] A Ka-band circularly polarized antenna includes a first dielectric layer, a second dielectric layer, a third dielectric layer, and a fourth dielectric layer arranged sequentially from top to bottom; it also includes a feeding structure and a SIW structure; a first radiating patch is provided on the upper surface of the first dielectric layer; a second radiating patch and a parasitic patch are provided on the upper surface of the second dielectric layer; both the first and second radiating patches are circular, and the parasitic patch is annular; the centers of the parasitic patch and the second radiating patch coincide, and the inner diameter of the parasitic patch is larger than the diameter of the second radiating patch;

[0006] The SIW structure includes a plurality of metal vias arranged in a circumferential array. The top of the metal vias contacts the lower surface of the parasitic patch, and the bottom of the metal vias is connected to a metal plate located on the lower surface of the fourth dielectric layer.

[0007] The power supply structure includes a first coaxial power supply structure and a second coaxial power supply structure; the top ends of both coaxial power supply structures are connected to the lower surface of the second radiating patch, and the bottom ends of both structures pass through the metal plate without contacting the metal plate.

[0008] Furthermore, the first radiating patch has two parallel rectangular through holes; the rectangular through holes are at an angle of 45° to the antenna axis, and the two rectangular through holes are rotationally symmetrical about the center of the first radiating patch.

[0009] Furthermore, the SIW structure includes 24 metal vias, each of which penetrates the second, third, and fourth dielectric layers and connects to the upper surface of the metal ground. The center of the array of metal vias is located directly below the center of the parasitic patch, the outer edge of the metal vias is tangent to the outer edge of the parasitic patch, and the included angle between adjacent metal vias is 15°.

[0010] Furthermore, the first, second, and fourth dielectric layers are made of the same dielectric material; the ratio of the first, second, and fourth dielectric layers is 2:3:1; the relative permittivity of the first, second, and fourth dielectric layers is 2.94; and the dielectric loss tangent is 0.0012. The third and fourth dielectric layers have the same thickness; the relative permittivity of the third dielectric layer is 10.2; and the dielectric loss tangent is 0.0023.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The antenna of this invention comprises a metal backplate, a dielectric layer, a feeding structure, a SIW structure, a radiating patch, and a parasitic patch. It achieves Ka-band circular polarization through a dual-port signal input with a 90° phase difference and coaxial feeding, while utilizing a special defect structure to achieve a high antenna axial ratio. This antenna can achieve circularly polarized signal output in the 26.38GHz-27.82GHz range, with an antenna axial ratio of 117°-152° below -3dB. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall antenna structure;

[0014] Figure 2 This is a side view of a Ka-band circularly polarized antenna;

[0015] Figure 3 This is a top view of a Ka-band circularly polarized antenna;

[0016] Figure 4 This is a graph showing the reflection coefficient of a Ka-band circularly polarized antenna.

[0017] Figure 5 This is a graph showing the axial ratio of the circular polarization of a Ka-band circularly polarized antenna.

[0018] Figure 6 This is a diagram showing the axial ratio width of a Ka-band circularly polarized antenna. Detailed Implementation

[0019] The following is in conjunction with the appendix Figure 1-3 The embodiments and examples will further illustrate specific implementations of the present invention in detail.

[0020] The Ka-band circularly polarized antenna includes a radiating layer: radiating patch 1, radiating patch defect structures 2 and 3; a feed network layer: radiating patch 5, parasitic patch 6; dielectric layers 4, 10, 11, and 12; a metal ground layer 13; and a SiW structure 9 with a total of 24 metal vias. The radiating patch 1 has characteristic defect structures 2 and 3, which are identical rectangular structures and symmetrically distributed about the diagonal of the antenna element. The feed structure includes coaxial feed lines 7 and 8, as well as radiating patch 5 and parasitic patch 6. The parasitic patch is a ring-shaped metal sheet with the same center as radiating patch 5. The SiW structure 9 contains 24 metal vias that penetrate dielectric layers 10, 11, and 12 and connect to the metal ground layer 13. The metal vias are distributed circularly below parasitic patch 6, with the outer edges of the vias tangent to the outer edges of parasitic patch 6. The 24 metal vias are equidistant from the center of the antenna element, and the angle between adjacent vias is 15°.

[0021] The antenna structure, from top to bottom, is detailed as follows:

[0022] The top layer is the radiating patch unit layer, which includes radiating patch 1 and patch defect structures 2 and 3. Radiating patch 1 is circular in shape; it contains characteristic defect structures 2 and 3, which are rectangular in shape and have an angle of 45° with the antenna axis. Structures 2 and 3 are symmetrically distributed about the diagonal of the antenna unit.

[0023] Below that is dielectric layer 4, which is 0.254 mm thick. The dielectric layer uses Rogers RT / duro id 6002 dielectric with a relative permittivity of 2.94 and a dielectric loss tangent of 0.0012.

[0024] The middle layer is the feed network layer, which includes coaxial feed structures 7 and 8, radiating patch 5, and parasitic patch 6. Coaxial feed structures 7 and 8 are distributed on the antenna element axis and are equidistant from the center of the antenna element axis. Radiating patch 5 is connected to feed structures 7 and 8 and is the same size as radiating patch 1. Parasitic patch 6 is a ring-shaped metal sheet that is grounded through the SIW structure. The center of parasitic patch 6 is the same as that of radiating patch 5.

[0025] Below this are dielectric layers 10, 11, and 12. The materials of dielectric layers 10 and 12 are the same as those of dielectric layer 4, and the thickness ratio of the three is 3:1:2. The thickness of dielectric layer 11 is the same as that of dielectric layer 12. Rogers RT / duro id 6010 is used, with a relative permittivity of 10.2 and a dielectric loss tangent of 0.0023.

[0026] The bottom layer is a metal backplate 13, which ensures unidirectional radiation of the antenna element and reduces the influence of the back components of the antenna on the antenna signal.

[0027] refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the overall structure of a Ka-band circularly polarized antenna. Figure 2 This is a side view of a Ka-band circularly polarized antenna. Figure 3 This is a top view of a Ka-band circularly polarized antenna element. (Example) Figure 1 As shown, the antenna consists of a radiating patch unit layer (including structures 1, 2, and 3), a dielectric layer 4, a feed network layer (including structures 5, 6, 7, 8, and 9), dielectric layers 10, 11, and 12, and a metal ground layer 13.

[0028] The top radiating patch 1 of the antenna contains defect structures 2 and 3. Defect structures 2 and 3 have the same structure and are characterized by a rectangular structure. They are symmetrically distributed about the diagonal of the antenna elements. Defect structures 2 and 3 can significantly optimize the axial ratio and width parameters of the antenna.

[0029] The size and position of the parasitic patch 6 affect the antenna beamwidth performance. The antenna signal is fed through feed networks 7 and 8. The signals fed into the two ports of the coaxial feed structure 7 and 8 are 90 degrees out of phase. The lower radiating patch 5 is circular. Together, these components ensure the purity of the circularly polarized wave at the operating frequency. When the antenna is in operation, the radiating patch 5 is excited, and through coupling, it excites the TM10 mode on the radiating patch 1, causing the radiating patch 1 to radiate a circularly polarized wave outwards. The size of the radiating patch 1 is used to adjust the antenna's center frequency; when its size decreases, the antenna's center frequency increases. The height of dielectric layers 4, 10, 11, and 12, and the size of the parasitic patch 6 affect the antenna's radiation pattern performance, ensuring that the antenna's circular polarization axial ratio at the operating frequency reaches more than 50 degrees on each side.

[0030] The metal vias of radiating patch 1, radiating patch 5, parasitic patch 6, and SIW structure 9, as well as the metal ground 13, are all made of metals with low resistivity, such as aluminum, copper, and gold, to reduce antenna loss.

[0031] Dielectric layers 4, 10, and 12 use Rogers RT / duroid 6002 with a relative permittivity of 2.94 and a dielectric loss tangent of 0.0012. Dielectric layer 11 uses Rogers RT / duroid 6010 with a relative permittivity of 10.2 and a dielectric loss tangent of 0.0023.

[0032] This dual-band circularly polarized antenna structure is illustrated here using a specific size combination:

[0033] Figure 2 Structures 1, 2, and 3 have a thickness of 0.018 mm; structure 4 has a thickness of 0.254 mm; structures 5 and 6 have a thickness of 0.018 mm; structure 10 has a thickness of 0.381 mm; structures 11 and 12 have a thickness of 0.127 mm; and structure 13 has a thickness of 0.018 mm. Structures 7, 8, and 9 have a length of 0.635 mm.

[0034] Figure 3 The specific dimensions of the antenna element structure are described below: the diameter width 14 of radiating patch structures 1 and 5 is 1.39 mm; the inner diameter width 15 of the annular parasitic patch 6 is 1.7 mm, and the outer diameter width 16 is 2.0 mm; the length 17 of defect structures 2 and 3 is 1.1 mm, and the width 18 is 0.1 mm; the diameter 19 of coaxial feed lines 7 and 8 is 0.2 mm; the diameter 20 of the metal through-hole of SIW structure 5 is 0.2 mm; the distance 21 from the outer edge of SIW structure 9 to the antenna axis is 2.0 mm; the included angle 22 between adjacent metal through-holes of SIW structure is 15°; the included angle 23 between defect structures 2 and 3 and the antenna axis is 45°; and the distance 24 from the coaxial feed line axis to the antenna element axis is 0.55 mm.

[0035] At this time, the simulation diagram of the antenna reflection coefficient S11 is as follows: Figure 4 As shown.

[0036] Figure 4 This is a reflection coefficient curve of the dual-band circularly polarized antenna. The image shows that the S11 parameter of the antenna is less than -10dB in the Ka band frequency range of 26.38GHz-27.82GHz and less than -15dB in the frequency range of 26.69GHz-27.64GHz, achieving high energy radiation performance in the antenna's operating frequency band.

[0037] At this point, the antenna axis ratio frequency simulation diagram is as follows: Figure 5 As shown.

[0038] Figure 5 This is the axial ratio curve of the dual-band circularly polarized antenna. The image shows that the axial ratio of the antenna is significantly lower than 3dB in the Ka band frequency range of 26.38GHz-27.82GHz, indicating that the antenna has excellent circular polarization characteristics when operating in the Ka band.

[0039] At this point, the antenna axial ratio width simulation diagram is as follows: Figure 6 As shown.

[0040] Figure 6 This is the axial ratio width curve of the dual-band circularly polarized antenna. With the center frequency selected as 27 GHz, the image shows that when the antenna is working at 27 GHz, the axial ratio width is 144.32° when Ph i equals 0° and 143.39° when Ph i equals 90°, indicating that the antenna has excellent circular polarization characteristics when working in the Ka band.

[0041] If it is necessary to change the performance parameters of this antenna to obtain antennas with different center frequencies, different parameters can be adjusted according to the specific implementation method. For example, the center frequency of the antenna can be adjusted by changing the size of the main radiating patch, the size of the parasitic patch, and the thickness of the dielectric substrate, and the impedance matching can be adjusted by adjusting the position of the port.

Claims

1. A Ka-band circularly polarized antenna, comprising a first dielectric layer, a second dielectric layer, a third dielectric layer, and a fourth dielectric layer arranged sequentially from top to bottom; characterized in that, It also includes a power supply structure and a SIW structure; a first radiating patch is provided on the upper surface of the first dielectric layer; a second radiating patch and a parasitic patch are provided on the upper surface of the second dielectric layer; both the first and second radiating patches are circular, and the parasitic patch is annular; the centers of the parasitic patch and the second radiating patch coincide, and the inner diameter of the parasitic patch is larger than the diameter of the second radiating patch. The SIW structure includes a plurality of metal vias arranged in a circumferential array. The top of the metal vias contacts the lower surface of the parasitic patch, and the bottom of the metal vias is connected to a metal plate located on the lower surface of the fourth dielectric layer. The power supply structure includes a first coaxial power supply structure and a second coaxial power supply structure; the top ends of both coaxial power supply structures are connected to the lower surface of the second radiating patch, and the bottom ends of both structures pass through the metal plate without contacting the metal plate. The first radiating patch has two parallel rectangular through holes; the rectangular through holes make an angle of 45° with the antenna axis, and the two rectangular through holes are rotationally symmetrical about the center of the first radiating patch; The first coaxial feed structure and the second coaxial feed structure have a 90-degree phase difference in the input signals.

2. The Ka-band circularly polarized antenna according to claim 1, characterized in that, The SIW structure includes 24 metal vias, each of which penetrates the second, third, and fourth dielectric layers and connects to the upper surface of the metal ground. The center of the array of metal vias is located directly below the center of the parasitic patch, the outer edge of the metal vias is tangent to the outer edge of the parasitic patch, and the included angle between adjacent metal vias is 15°.

3. A Ka-band circularly polarized antenna according to claim 1, characterized in that: The first, second, and fourth dielectric layers are made of the same dielectric material; the thickness ratio of the first, second, and fourth dielectric layers is 2:3:1; the relative permittivity of the first, second, and fourth dielectric layers is 2.94; and the dielectric loss tangent is 0.0012. The third and fourth dielectric layers are made of the same thickness; the relative permittivity of the third dielectric layer is 10.2; and the dielectric loss tangent is 0.0023.

Images