Dual-band airborne common-aperture antenna

Abstract

The application relates to a dual-band airborne common-aperture antenna, which comprises a first dielectric substrate and a second dielectric substrate arranged on a system ground, a 5G-band rectangular monopole antenna arranged on the first dielectric substrate and the second dielectric substrate, an S-band U-shaped monopole antenna and an open loop metamaterial structure arranged on the front surface of the first dielectric substrate; a defect ground connected with the system ground perpendicularly is arranged on the back surface of the first dielectric substrate, a circular groove is arranged in the center of the defect ground, and an egg-shaped metal sheet is loaded on the circular groove; a plurality of feeding connectors are arranged on the back surface of the system ground, and the U-shaped monopole antenna and the rectangular monopole antenna are connected with the coaxial cables in the feeding connectors for feeding. In the application, the overall layout of the antenna is in a trapezoidal distribution, and the metamaterial decoupling technology is used, so that the isolation degree between the antenna units in the whole system is obviously improved, thereby the communication performance of the antenna system is improved, and the compactness of the antenna system is considered.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a dual-band airborne common-aperture antenna. Background Technology

[0002] With the rapid development of the electronics industry, the demand for electronic devices integrating multiple functions is constantly increasing, and the design difficulty is also gradually increasing. As one of these important electronic devices, drones are developing rapidly in both civilian and military fields. In the civilian sector, drones are already being used for aerial photography, search and rescue, precision agriculture, aerial pipeline and power line monitoring and mapping, wildlife monitoring and surveillance, disaster relief personnel management and delivery of medical supplies, etc. In the military field, multi-band, multi-functional radios and broadband frequency-hopping radios are widely used to achieve secure communication and eliminate interference. Due to increasingly higher frequency hopping rates and wider frequency hopping ranges, existing narrowband antennas can no longer meet the requirements.

[0003] Airborne antennas can be considered an important component of aircraft structure, but the geometry and size of the aircraft have a significant impact on the electrical performance of airborne antennas. The selection of airborne antenna type is often determined by the size of the aircraft. Currently, the mainstream choices for UAV antennas are blade antennas, linear monopoles, printed monopoles, dipoles, and loop slot antennas. In contrast, printed monopoles / dipoles can be directly and seamlessly connected to the UAV fuselage, while blade antennas or linear monopoles require radomes for protection. Traditional airborne antennas typically utilize one or two types of antennas. For example, existing technology proposes a dual-band omnidirectional circularly polarized airborne antenna. This antenna can generate dual-band circular polarization and circular polarization characteristics. This antenna achieves miniaturization using left and right hand transmission lines. The main shortcomings of this antenna compared to this design are: 1. This antenna achieves dual-band characteristics with a single antenna, and cannot improve the information transmission rate and bandwidth utilization like a MIMO antenna system. 2. The metamaterial structure (left and right hand transmission lines) of this antenna is mainly used to achieve miniaturization, while the metamaterial in this design is used to increase the isolation between antenna elements. 3. This antenna is a circularly polarized antenna, while this design requires a vertically polarized antenna. Also, a dual-band common-aperture circularly polarized antenna, consisting of one UHF band antenna and four S-band antennas. This antenna has a complex structure, consisting of four microstrip antenna layers and six dielectric substrate layers stacked together. This common-aperture antenna has a -10dB bandwidth of 52.6% in the UHF band and a bandwidth of 16.3% in the S-band. The main shortcomings of this antenna compared to this design are: 1. Although this antenna has dual-band and common-aperture characteristics, both antennas are microstrip patch type and not omnidirectional radiating antennas, resulting in signal blind spots in certain directions during communication. 2. The antenna's radiating frequency band is not a 5G band, making it incompatible with the rapidly developing 5G technology. 3. The antenna is composed of six substrate layers, resulting in a complex structure, uncontrollable manufacturing precision, and potential performance impact.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-band airborne common aperture antenna, which solves the deficiencies of existing antennas.

[0006] The objective of this invention is achieved through the following technical solution: a dual-band airborne common-aperture antenna, comprising a first dielectric substrate and a second dielectric substrate disposed on the ground of the system, a 5G band rectangular monopole antenna disposed on the first dielectric substrate and the second dielectric substrate, and an S-band U-shaped monopole antenna and an open-loop metamaterial structure disposed on the front side of the first dielectric substrate.

[0007] A defect ground is provided on the back side of the first dielectric substrate, which is perpendicularly connected to the system ground. A circular groove is formed in the center of the defect ground, and an egg-shaped metal sheet is loaded on the circular groove. The U-shaped monopole antenna is located directly below the egg-shaped metal sheet and within the range of the circular groove. The defect ground improves the impedance matching performance of the U-shaped monopole antenna through the circular groove and the egg-shaped metal sheet. Multiple feed connectors are provided on the back side of the system ground, and the U-shaped monopole antenna and the rectangular monopole antenna are connected to the feed connectors through coaxial cables for feeding.

[0008] The rectangular monopole antenna includes a first rectangular monopole antenna, a second rectangular monopole antenna, a third rectangular monopole antenna, and a fourth rectangular monopole antenna;

[0009] The first rectangular monopole antenna and the second rectangular monopole antenna are arranged on the left and right sides of the upper back of the first dielectric substrate.

[0010] The third rectangular monopole antenna and the fourth rectangular monopole antenna are arranged on the left and right sides of the front side of the second dielectric substrate.

[0011] The open-ring metamaterial structure includes a complementary first open ring and a second open ring, which are disposed on the upper end of the front side of the first dielectric substrate and located between the first rectangular monopole antenna and the second rectangular monopole antenna to improve the isolation between the first rectangular monopole antenna and the second rectangular monopole antenna.

[0012] The system also includes a metal strip disposed on the back side of the second dielectric substrate, which tightly connects the second dielectric substrate and the system ground.

[0013] The length of the first dielectric substrate is greater than the length of the second dielectric substrate, and the height of the first dielectric substrate is less than the height of the second dielectric substrate, so that the first rectangular monopole antenna and the second rectangular monopole antenna arranged on the first dielectric substrate form a non-linear trapezoidal layout with the third rectangular monopole antenna and the fourth rectangular monopole antenna arranged on the second dielectric substrate, so as to improve the isolation effect between the four rectangular monopole antennas.

[0014] The U-shaped monopole antenna is located between the third rectangular monopole antenna and the fourth rectangular monopole antenna to improve the isolation effect between the third rectangular monopole antenna and the fourth rectangular monopole antenna.

[0015] The present invention has the following advantages:

[0016] 1. By fusing the nonlinear layout of the 5G MIMO antenna and the airborne S-band antenna, the communication performance of the antenna system is further improved, enabling real-time transmission and rapid response of aircraft flight data to the ground, and realizing the application of 5G private network on aircraft.

[0017] 2. The overall layout is trapezoidal and utilizes metamaterial decoupling technology, which significantly improves the isolation between antenna elements in the entire system, thereby improving the communication performance of the antenna system while maintaining its compactness.

[0018] 3. The S-band monopole antenna, although located in the 5G MIMO antenna element, still has good omnidirectional radiation characteristics. Compared with a single antenna, the 5G MIMO antenna has the characteristics of improving channel capacity and resisting multipath fading.

[0019] 4. Dual-band antenna, including S-band and 5G band. The isolation between the S-band antenna and the 5G band MIMO antenna elements is not less than 25dB, and the isolation between the monopole antenna elements is not less than 15dB. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the reflection coefficient Snn (n = 2-5) of a 5G MIMO antenna element;

[0022] Figure 3 This is a schematic diagram of the isolation Sn1 (n=2-5) between the S-band and 5G-band antenna elements;

[0023] Figure 4 A schematic diagram of the isolation Smn (m, n = 2-5) between antenna elements in the 5G band;

[0024] Figure 5 A schematic diagram of the reflection coefficient of an S-band U-shaped monopole antenna;

[0025] Figure 6 The horizontal radiation pattern of the S-band U-shaped monopole antenna at 2.3 GHz.

[0026] Figure 7 The horizontal plane gain non-circularity of the S-band U-shaped monopole antenna at 2.3 GHz;

[0027] In the diagram: S1 - First dielectric substrate, S2 - Second dielectric substrate, G1 - System ground, G2 - Metal strip, G3 - Defect ground, G31 - Circular groove, G32 - Egg-shaped metal sheet, R1 - First open ring, R2 - Second open ring, A1 - U-shaped monopole antenna, A2 - First rectangular monopole antenna, A3 - Second rectangular monopole antenna, A4 - Third rectangular monopole antenna, A5 - Fourth rectangular monopole antenna. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this application provided below with reference to the accompanying drawings is not intended to limit the scope of protection of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The present invention will be further described below with reference to the accompanying drawings.

[0029] This invention relates to a common-aperture antenna for an unmanned aerial vehicle (UAV) airborne platform operating in the 5G band (4.8-4.9GHz) and S-band (2.2-2.4GHz). It consists of a vertically polarized omnidirectional U-shaped monopole antenna A1 and a nonlinearly distributed rectangular monopole MIMO antenna. The U-shaped monopole antenna A1 is located between two relatively far rectangular monopole antenna elements, while two complementary open-loop metamaterial structures are located between two relatively close rectangular monopole antenna elements. By utilizing the nonlinear layout of the 5G band MIMO antenna combined with electromagnetic metamaterial technology, the isolation between 5G antenna elements and between the 5G antenna elements and the S-band antenna is improved, achieving a better isolation effect.

[0030] like Figure 1 As shown, it includes a first dielectric substrate S1 and a second dielectric substrate S2 disposed on the system ground G1. A rectangular monopole antenna (MIMO antenna) of 5G band is disposed on the first dielectric substrate S1 and the second dielectric substrate S2. A U-shaped monopole antenna A1 of S band and an open ring metamaterial structure are disposed on the front side of the first dielectric substrate S1.

[0031] A defect ground G3, perpendicularly connected to the system ground G1, is provided on the back side of the first dielectric substrate S1. A circular slot G31 is formed in the center of the defect ground G3, and an egg-shaped metal sheet G32 is loaded on the circular slot G31. The U-shaped monopole antenna A1 is located directly below the egg-shaped metal sheet G32 and within the range of the circular slot G31. The circular slot G31 and the egg-shaped metal sheet G32 improve the impedance matching performance of the U-shaped monopole antenna through the defect ground G3. Multiple feed connectors are provided on the back side of the system ground G1, and the U-shaped monopole antenna and the rectangular monopole antenna are fed through the coaxial cables in the feed connectors.

[0032] Furthermore, the rectangular monopole antenna includes a first rectangular monopole antenna A2, a second rectangular monopole antenna A3, a third rectangular monopole antenna A4, and a fourth rectangular monopole antenna A5; the first rectangular monopole antenna A2 and the second rectangular monopole antenna A3 are arranged on the left and right sides of the upper back of the first dielectric substrate S1; the third rectangular monopole antenna A4 and the fourth rectangular monopole antenna A5 are arranged on the left and right sides of the front of the second dielectric substrate S2.

[0033] Furthermore, the open-ring metamaterial structure includes a complementary first open-ring R1 and a second open-ring R2, which are disposed on the upper end of the front side of the first dielectric substrate S1 and located between the first rectangular monopole antenna A2 and the second rectangular monopole antenna A3 to improve the isolation between the first rectangular monopole antenna A2 and the second rectangular monopole antenna A3.

[0034] It also includes a metal strip G2 disposed on the back side of the second dielectric substrate S2, which tightly connects the second dielectric substrate S2 and the system ground G1.

[0035] The length of the first dielectric substrate S1 is greater than the length of the second dielectric substrate S2, and the height of the first dielectric substrate S1 is less than the height of the second dielectric substrate S2. This results in a non-linear trapezoidal layout between the first rectangular monopole antenna A2 and the second rectangular monopole antenna A3 arranged on the first dielectric substrate S1 and the third rectangular monopole antenna A4 and the fourth rectangular monopole antenna A5 arranged on the second dielectric substrate S2, thereby improving the isolation effect between the four rectangular monopole antennas.

[0036] The U-shaped monopole antenna A1 is located between the third rectangular monopole antenna A4 and the fourth rectangular monopole antenna A5 to improve the isolation effect between the third rectangular monopole antenna A4 and the fourth rectangular monopole antenna A5.

[0037] Furthermore, in actual use, the antenna will be protected by a radome, and the S-band antenna will be fed using a 50-ohm N connector, while the 5G band MIMO antenna will be fed using a 50-ohm SMA connector and a coaxial cable.

[0038] Specifically, in this invention, one S-band U-shaped monopole antenna A1 and two 5G rectangular monopole antennas are located on the front side of the dielectric substrate, while the other two 5G rectangular monopole antennas and two complementary open rings are located on the back side of the dielectric substrate. The 5G rectangular monopole antennas consist of four identical rectangular patch antennas, forming a 4-element MIMO antenna with an overall trapezoidal shape. The back side of the S-band U-shaped monopole antenna A1 has a defective ground structure, which can further improve the impedance matching performance of the U-shaped antenna. The S-band U-shaped monopole antenna A1 and the 5G MIMO antennas operate in the S-band and 5G bands respectively, forming a dual-band configuration. The S-band U-shaped monopole antenna A1 and the two 5G MIMO antennas are fed by a 50-ohm connector, while the other two 5G MIMO antenna elements are fed by a coaxial cable, for a total of five feed ports. The two complementary metal open rings possess electromagnetic metamaterial properties, which can reduce electromagnetic coupling between antenna elements, thereby increasing the isolation between each antenna element. Given limited space, the isolation requirements between antenna elements are met by adjusting the spacing between elements and adding metamaterial structures, while also considering the antenna's impedance matching and radiation performance.

[0039] The reflection coefficient and isolation of the present invention are as follows Figures 2-5 As shown, Figure 2 The reflection coefficient Snn (n = 2-5) is calculated when feeding four 5G MIMO antenna elements and applying 50 ohms impedance matching to the remaining ports. Figure 3 The isolation Sn1 (n=2-5) between the S-band antenna and the four 5G band antenna elements is provided. Figure 4 To determine the isolation Smn (m,n = 2-5) between 5G band antenna elements, representative isolation curves were selected based on the antenna layout and simulation results, namely S32, S42, S53 and S54. Figure 5 The reflection coefficient of the S-band U-shaped monopole antenna. The radiation performance and non-circularity of the S-band antenna are as follows: Figure 6 and Figure 7 As shown, Figure 6 The radiation pattern of the S-band U-shaped monopole antenna in the horizontal plane (XOY plane) at a frequency of 2.3 GHz; Figure 7 The image shows the horizontal gain non-circularity of the S-band U-shaped monopole antenna at 2.3 GHz. The gain fluctuates between -1.75 dB and 0.5 dB, indicating good non-circularity.

[0040] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A dual-band airborne common-aperture antenna, characterized in that: It includes a first dielectric substrate (S1) and a second dielectric substrate (S2) disposed on a system ground (G1), a 5G band rectangular monopole antenna is disposed on the first dielectric substrate (S1) and the second dielectric substrate (S2), and an S-band U-shaped monopole antenna (A1) and an open-loop metamaterial structure are disposed on the front side of the first dielectric substrate (S1). A defect ground (G3) perpendicularly connected to the system ground (G1) is provided on the back side of the first dielectric substrate (S1). A circular groove (G31) is formed in the center of the defect ground (G3), and an egg-shaped metal piece (G32) is loaded on the circular groove (G31). The U-shaped monopole antenna (A1) is located directly below the egg-shaped metal piece (G32) and within the range of the circular groove (G31). The defect ground (G3) improves the impedance matching performance of the U-shaped monopole antenna through the circular groove (G31) and the egg-shaped metal piece (G32). Multiple feed connectors are provided on the back side of the system ground (G1), and the U-shaped monopole antenna and the rectangular monopole antenna are connected to the feed connectors through coaxial cables for feeding. The rectangular monopole antenna includes a first rectangular monopole antenna (A2), a second rectangular monopole antenna (A3), a third rectangular monopole antenna (A4), and a fourth rectangular monopole antenna (A5). The first rectangular monopole antenna (A2) and the second rectangular monopole antenna (A3) are arranged on the left and right sides of the upper back of the first dielectric substrate (S1); The third rectangular monopole antenna (A4) and the fourth rectangular monopole antenna (A5) are arranged on the left and right sides of the front side of the second dielectric substrate (S2).

2. The dual-band airborne common-aperture antenna according to claim 1, characterized in that: The open-ring metamaterial structure includes a complementary first open-ring (R1) and a second open-ring (R2). The first open-ring (R1) and the second open-ring (R2) are arranged on the upper end of the front side of the first dielectric substrate (S1) and are located between the first rectangular monopole antenna (A2) and the second rectangular monopole antenna (A3) to improve the isolation between the first rectangular monopole antenna (A2) and the second rectangular monopole antenna (A3).

3. A dual-band airborne common-aperture antenna according to claim 1 or 2, characterized in that: It also includes a metal strip (G2) disposed on the back side of the second dielectric substrate (S2), through which the second dielectric substrate (S2) and the system ground (G1) are tightly connected.

4. A dual-band airborne common-aperture antenna according to claim 3, characterized in that: The length of the first dielectric substrate (S1) is greater than the length of the second dielectric substrate (S2), and the height of the first dielectric substrate (S1) is less than the height of the second dielectric substrate (S2), so that the first rectangular monopole antenna (A2) and the second rectangular monopole antenna (A3) arranged on the first dielectric substrate (S1) form a non-linear trapezoidal layout with the third rectangular monopole antenna (A4) and the fourth rectangular monopole antenna (A5) arranged on the second dielectric substrate (S2), so as to improve the isolation effect between the four rectangular monopole antennas.

5. A dual-band airborne common-aperture antenna according to claim 3, characterized in that: The U-shaped monopole antenna (A1) is located between the third rectangular monopole antenna (A4) and the fourth rectangular monopole antenna (A5) to improve the isolation effect between the third rectangular monopole antenna (A4) and the fourth rectangular monopole antenna (A5).

Images