Ku-band broadband circularly polarized microstrip antenna based on satellite communication

Abstract

The invention belongs to the field of satellite communication, and relates to a satellite communication-based Ku-band broadband circularly polarized microstrip antenna, which comprises a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first metal grounding plate, a fourth dielectric substrate and a second metal grounding plate from top to bottom, the third dielectric substrate is provided with a first feed network, the fourth dielectric substrate is provided with a second feed network, and the first metal grounding plate is provided with a square-shaped gap; the square-shaped slot is arranged on the first metal grounding plate between the third dielectric substrate and the fourth dielectric substrate for coupled feeding, the distance of a coupling slot at a slot coupling position can be shortened by the square-shaped slot, so that miniaturization of the antenna is realized, and a current path is not interrupted due to the fact that the square-shaped slot is a continuous closed loop, so that the miniaturization of the antenna is realized. Therefore, differential feed on the two sides can be balanced to suppress a parasitic mode, an electromagnetic field can be better restrained, outward leakage of the field and unnecessary coupling between feed layers are reduced, and the isolation between feed ports is improved.

Description

Technical Field

[0001] The invention belongs to the field of satellite communications and relates to a Ku-band broadband circularly polarized microstrip antenna based on satellite communications. Background Art

[0002] The rapid development of global satellite communication technology, including the deployment of low-orbit satellite constellations (such as Starlink and OneWeb), high-throughput satellites (HTS), and integrated space-ground networks, has placed higher demands on terminal antenna performance. Satellite communication systems must achieve high-speed, stable, and multi-scenario data transmission in complex electromagnetic environments. This poses stringent challenges to antennas' broadband characteristics, circular polarization performance, low-profile structure, and environmental adaptability. Microstrip antennas, with their lightweight, conformable, low-cost, and easy integration, are an ideal choice for satellite communication terminals.

[0003] Existing Ku-band satellite communication antennas have limitations in terms of miniaturization, broadband, and high isolation. Existing antennas are large, limiting their portability and integration in space-constrained scenarios (such as onboard equipment). Furthermore, their narrow bandwidth cannot meet the requirements of high-frequency multi-band communications. Furthermore, low inter-polarization isolation can easily lead to signal cross-coupling and interference, impacting the stability and anti-interference capabilities of the communication system. Summary of the Invention

[0004] To solve the above-mentioned problems in the prior art, the present invention adopts a Ku-band broadband circularly polarized microstrip antenna based on satellite communication, which includes, from top to bottom: a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a first metal ground plate 5, a fourth dielectric substrate 4 and a second metal ground plate 6. The third dielectric substrate 3 is provided with a first feeding network, the fourth dielectric substrate 4 is provided with a second feeding network, and the first metal ground plate 5 is provided with a U-shaped gap.

[0005] Beneficial effects:

[0006] The present invention arranges two feeding networks of a differential feeding network on a third dielectric substrate and a fourth dielectric substrate, respectively, to improve feeding isolation, and arranges a U-shaped slot coupling feeding on the first metal ground planes in the third dielectric substrate and the fourth dielectric substrate. The U-shaped slot can shorten the distance between the coupling slots at the slot coupling point, thereby achieving miniaturization of the antenna. Moreover, because the U-shaped slot is a continuous closed loop, the current path is not interrupted, thereby balancing the differential feeding on both sides to suppress parasitic modes, reduce outward field leakage and unnecessary coupling between feeding layers, and improve isolation between feeding ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A structural diagram of a Ku-band broadband circularly polarized microstrip antenna based on satellite communications provided by an embodiment of the present invention;

[0008] Figure 2 A schematic diagram of an antenna feed network provided in an embodiment of the present invention;

[0009] Figure 3 A top view of a second dielectric substrate provided by an embodiment of the present invention;

[0010] Figure 4 A top view of a first dielectric substrate provided by an embodiment of the present invention;

[0011] Figure 5 A simulation diagram of the return loss parameters of the antenna provided in an embodiment of the present invention;

[0012] Figure 6 A simulation diagram of the axial ratio bandwidth of the antenna provided in an embodiment of the present invention;

[0013] Figure 7 A simulation diagram of antenna gain bandwidth provided by an embodiment of the present invention;

[0014] Figure 8 A simulation diagram of antenna port isolation provided by an embodiment of the present invention;

[0015] Among them, 1 is the first dielectric substrate, 2 is the second dielectric substrate, 3 is the third dielectric substrate, 4 is the fourth dielectric substrate, 5 is the first metal ground plate, 6 is the second metal ground plate, 7 is the circular parasitic patch, 8 is the circular patch, 9 is the first Schiffman phase shifter, 10 is the second Schiffman phase shifter, 11 is the first T-junction, and 12 is the second T-junction. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, the present invention adopts a Ku-band broadband circularly polarized microstrip antenna based on satellite communication, which includes, from top to bottom: a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a first metal ground plate 5, a fourth dielectric substrate 4, and a second metal ground plate 6; wherein, an air gap layer is provided between the first dielectric substrate 1 and the second dielectric substrate 2, and an air gap layer is provided between the second dielectric substrate 2 and the third dielectric substrate 3.

[0018] The first dielectric substrate 1, the second dielectric substrate 2, the third dielectric substrate 3 and the fourth dielectric substrate 4 are made of Rogers 4350 material, which is a glass cloth reinforced ceramic filled hydrocarbon composite material. Due to its excellent high-frequency performance and processing performance, it is widely used in wireless communications, satellite communications, radar, microwave communications and other fields.

[0019] like Figure 4 As shown, a circular parasitic patch 7 is provided on the first dielectric substrate 1. The parasitic patch 7 can better optimize the scattering parameter S of the antenna, and the parasitic patch can further improve the radiation efficiency of the antenna.

[0020] like Figure 3 As shown, the second dielectric substrate 2 is provided with a circular patch 8, on which a cross-shaped slot is etched. Etching the cross-shaped slot introduces an additional resonance point, thereby expanding the bandwidth of the antenna. In addition, the current path can be changed by adjusting the length of the cross-shaped slot, thereby extending the effective current path. The extension of the current path is equivalent to increasing the electrical length, so that the antenna originally operating at a certain frequency behaves like a larger antenna, thereby reducing the resonant frequency and miniaturizing the antenna.

[0021] like Figure 2 As shown, in order to improve isolation, the present invention sets a differential feeding network, and sets two networks of the differential feeding network on two substrates respectively, that is, the third dielectric substrate 3 is provided with a first feeding network, and the fourth dielectric substrate 4 is provided with a second feeding network. The first feeding network and the second feeding network constitute the antenna feeding network.

[0022] The first feeding network includes a first Schiffman 180-degree phase shifter 9 and a first T-junction 11. The second feeding network includes a second Schiffman 180-degree phase shifter 10 and a second T-junction 12. The first Schiffman 180-degree phase shifter 9, the second Schiffman 180-degree phase shifter 10, the first T-junction 11, and the second T-junction 12 are composed of microstrip lines.

[0023] The input end of the first T-junction 11 is connected to the external signal, and the output end is connected to the input end of the first Schiffman 180-degree phase shifter 9, for splitting the external signal into two signals and distributing them to the two transmission lines of the first Schiffman 180-degree phase shifter 9 respectively.

[0024] The input end of the second T-junction 12 is connected to the external signal, and the output end is connected to the input end of the second Schiffman 180-degree phase shifter 10 , for splitting the external signal into two signals and distributing them respectively to the two transmission lines of the second Schiffman 180-degree phase shifter 10 .

[0025] The first Schiffman phase shifter 9 and the second Schiffman phase shifter 10 each include two output ends, and the phases of the signals output by the two output ends differ by 180 degrees; the two output ends of the first Schiffman phase shifter 9 are respectively perpendicularly intersected with two mutually parallel slots in the U-shaped slot, and the two output ends of the second Schiffman phase shifter 10 are respectively perpendicularly intersected with the other two mutually parallel slots in the U-shaped slot.

[0026] The surface metal layer on the first metal ground plate 5 is provided with gaps for coupling energy in the antenna feeding network composed of the feeding networks of the upper and lower substrates.

[0027] Conventional slots (cross-shaped, H-shaped, etc.) carry discontinuous current, introducing higher-order modes or parasitic modes, thereby affecting axial ratio and isolation. Because a U-shaped slot is a continuous closed loop with an uninterrupted current path, it balances the differential feeds on both sides to suppress parasitic modes, reduce outward field leakage and unnecessary coupling between feed layers, and improve isolation between feed ports. Therefore, the present invention configures the slots on the first metal ground plane 5 as U-shaped slots.

[0028] Compared to conventional slot-coupled feed (cross-shaped and H-shaped slot-coupled feed) microstrip antennas, the U-shaped slot feed has closer spacing between adjacent slots, shifting the resonant point at the feed slot toward a higher frequency, resulting in a higher resonant frequency and a smaller wavelength. The spacing between slots producing the same polarization is generally 1 / 2 the wavelength of the dielectric, miniaturizing the antenna. Adjusting the length and width of the U-shaped coupling slots adjusts the resonant frequency and feed coupling strength of the feed slot, respectively.

[0029] like Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 As shown, the antenna has a relative bandwidth of 31.4%, a full coverage of the 3dB axial ratio (Axial Ratio Value) bandwidth, a maximum gain (Gain Total) of 7.46dB, and an isolation greater than 20dB at a frequency (Freq) of 10.12GHz to 13.58GHz. Therefore, the antenna of the present invention outperforms existing antenna technologies in terms of bandwidth and axial ratio bandwidth.

[0030] The above embodiments further illustrate the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above embodiments are only preferred implementation plans of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Ku-band broadband circularly polarized microstrip antenna for satellite communications, comprising, from top to bottom: A first dielectric substrate (1), a second dielectric substrate (2), a third dielectric substrate (3), a first metal grounding plate (5), a fourth dielectric substrate (4), and a second metal grounding plate (6), characterized in that the third dielectric substrate (3) is provided with a first feeding network, the fourth dielectric substrate (4) is provided with a second feeding network, and the first metal grounding plate (5) is provided with a square-shaped gap.

2. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 1, characterized in that: The first feeding network comprises: a first Schiffman phase shifter (9) and a first T-junction (11), wherein the output end of the first T-junction (11) is connected to the input end of the first Schiffman phase shifter (9); and the second feeding network comprises: a second Schiffman phase shifter (10) and a second T-junction (12), wherein the output end of the second T-junction (12) is connected to the input end of the second Schiffman phase shifter (10).

3. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 2, characterized in that: The first Schiffman phase shifter (9) and the second Schiffman phase shifter (10) are both Schiffman 180-degree phase shifters.

4. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 2, characterized in that: The first Schiffman phase shifter (9) and the second Schiffman phase shifter (10) each include two output ends; the two output ends of the first Schiffman phase shifter (9) respectively cross perpendicularly with two mutually parallel slots in the U-shaped slot, and the two output ends of the second Schiffman phase shifter (10) respectively cross perpendicularly with the other two mutually parallel slots in the U-shaped slot.

5. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 1, characterized in that: An air gap layer is respectively provided between the first dielectric substrate (1) and the second dielectric substrate (2), and between the second dielectric substrate (2) and the third dielectric substrate (3).

6. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 1, characterized in that: A circular parasitic patch (7) is provided on the first dielectric substrate (1).

7. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 1, characterized in that: A circular patch (8) is provided on the second dielectric substrate (2).

8. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 7, characterized in that: A cross-shaped gap is etched on the circular patch (8).

9. The Ku-band broadband circularly polarized microstrip antenna based on satellite communication according to claim 1, characterized in that: The materials of the first dielectric substrate (1), the second dielectric substrate (2), the third dielectric substrate (3) and the fourth dielectric substrate (4) are Rogers 4350 materials.

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