A broadband circularly polarized antenna

Abstract

The application provides a broadband circularly polarized antenna, comprising a feed network, a feed patch, a radiator, a metal enclosure and a metal bottom plate; wherein the feed network is used for transmitting signals and is directly or electromagnetically coupled to the feed patch; a coupling feed area is formed between the feed patch and the radiator, and the feed patch electromagnetically couples to feed the radiator through the coupling feed area; the metal enclosure is arranged on the metal bottom plate, and the metal enclosure surrounds the feed network, the feed patch and the radiator; and the metal bottom plate serves as a reference ground of the radiator. The application can effectively improve the working bandwidth, beam width and antenna axial ratio performance of the unit antenna, and further improve the working bandwidth, antenna axial ratio and overall coverage range of the array antenna.

Description

Technical Field

[0001] This invention relates to the field of satellite communication antenna technology, and in particular to a broadband circularly polarized antenna. Background Technology

[0002] The existing mainstream satellite communication phased array antennas at home and abroad have limited coverage areas. At large scanning angles, both the axial ratio and gain deteriorate rapidly. In addition, in order to reduce the profile and facilitate integration with circuits, the array elements usually adopt microstrip antennas, which have a narrow operating bandwidth. Summary of the Invention

[0003] This application provides a broadband circularly polarized antenna to solve the problems in the background art.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] According to a first aspect of the present application, a broadband circularly polarized antenna is provided, including a feed network, a feed piece, a radiator, a metal frame, and a metal base plate; wherein, the feed network is used to transmit signals and is connected to the feed piece; a coupling feed region is formed between the feed piece and the radiator, and the feed piece electromagnetically couples the radiator through the coupling feed region; the metal frame is disposed on the metal base plate, and the metal frame surrounds the feed network, the feed piece, and the radiator; the metal base plate serves as a reference ground for the radiator.

[0006] In one embodiment of this application, the metal frame is directly connected to the metal base plate or electromagnetically coupled to it.

[0007] In one embodiment of this application, the power supply network is directly connected to the power supply plate or electromagnetically coupled to it.

[0008] In one embodiment of this application, the broadband circularly polarized antenna includes four feed plates, which respectively form four coupled feed regions with the radiator; the feed network is divided into four paths, which are directly connected to or electromagnetically coupled to the four feed plates respectively.

[0009] In one embodiment of this application, the four input signals in the power supply network have equal amplitudes or amplitudes that differ by a maximum of 6dB, and their phases differ by 90° clockwise or counterclockwise, or by 90°±30°.

[0010] In one embodiment of this application, the power supply network is implemented using metal pillars or transmission lines.

[0011] In one embodiment of this application, the projections of the four coupled feed regions are located inside or at the edge of the radiator.

[0012] In one embodiment of this application, the radiator includes four independent sub-radiators that are not directly electrically connected.

[0013] In one embodiment of this application, the broadband circularly polarized antenna includes one or more layers of radiators and feed plates. When multiple layers of radiators and feed plates are included, each layer of radiators and feed plates are alternately arranged vertically, and each layer of feed plates is coaxially arranged.

[0014] In one embodiment of this application, the broadband circularly polarized antenna is applicable to satellite communication antennas across all frequency bands.

[0015] Compared with the prior art, the beneficial effects of adopting the above technical solution are as follows: By designing the radiating patch at the feed port of the antenna element, this application can effectively improve the working bandwidth, beamwidth, and antenna axial ratio performance of the element antenna, thereby improving the working bandwidth, antenna axial ratio, and overall coverage of the array antenna. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] Figure 1 This is a schematic diagram of a broadband circularly polarized antenna according to an embodiment of this application.

[0018] Figure 2 This is a schematic diagram of an existing L-band microstrip patch circularly polarized antenna.

[0019] Figure 3 This is a schematic diagram of the broadband circularly polarized antenna structure of Embodiment 1 of this application.

[0020] Figure 4 This is a cross-sectional view of the broadband circularly polarized antenna of Embodiment 1 of this application.

[0021] Figure 5 This is a schematic diagram of the broadband circularly polarized antenna structure of Embodiment 2 of this application.

[0022] Figure 6 This is a cross-sectional view of the broadband circularly polarized antenna of Embodiment 2 of this application.

[0023] Figure 7 This is a schematic diagram of the broadband circularly polarized antenna structure of Embodiment 3 of this application.

[0024] Figure 8 This is a cross-sectional view of the broadband circularly polarized antenna of Embodiment 3 of this application.

[0025] Figure 9 This is a schematic diagram of the broadband circularly polarized antenna structure of Embodiment 4 of this application.

[0026] Figure 10 This is a cross-sectional view of the broadband circularly polarized antenna of Embodiment 4 of this application. Detailed Implementation

[0027] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar modules or modules having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Rather, the embodiments of this application include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0028] To address the shortcomings of existing technologies and improve the antenna's operating bandwidth, axial ratio, and overall coverage, this application proposes a broadband circularly polarized antenna.

[0029] Please refer to Figure 1 The broadband circularly polarized antenna mainly includes a feed network, a feed plate, a radiator, a metal frame, and a metal base plate. The feed network is used to transmit signals and is connected to the feed plate. A coupling feed region is formed between the feed plate and the radiator, and the feed plate electromagnetically couples the radiator through this region. The metal frame is disposed on the metal base plate, surrounding the feed network, feed plate, and radiator. The metal base plate serves as the reference ground for the radiator.

[0030] Furthermore, in this embodiment, the metal frame is directly connected to the metal base plate or electromagnetically coupled, and the power supply network is directly connected to the power supply plate or electromagnetically coupled.

[0031] It should be noted that in this broadband circularly polarized antenna, neither the feed network nor the feed plate is directly electrically connected to the radiator. The signal passes through the feed network and the feed plate, and then electromagnetically couples to the radiator through the coupling feed region.

[0032] In this embodiment, the broadband circularly polarized antenna includes four feed plates, which respectively form four coupled feed regions with the radiator; the feed network is divided into four paths, which are directly connected to or electromagnetically coupled to the four feed plates respectively. The signal amplitudes fed into the four paths in the feed network are equal or the maximum difference in amplitude value is within 6dB, and the phases differ by 90° clockwise or counterclockwise, or by 90°±30°.

[0033] In one embodiment, the power supply network is presented in the form of metal pillars. In actual implementation, the power supply network can also be in the form of microstrip lines, striplines, coaxial lines, or any other type of transmission line.

[0034] The polarization of an antenna can be changed by controlling the amplitude and phase characteristics of the feed network. Figure 1 The center feed network has four feed ports. If the amplitude of the signals excited at the ports is equal and the phase is delayed by 90° clockwise, then the main polarization of the antenna is right circular polarization. If the amplitude of the signals excited at the ports is equal and the phase is delayed by 90° counterclockwise, then the main polarization of the antenna is left circular polarization.

[0035] This application employs an electromagnetic coupling feeding method in the coupled feeding region, primarily used to extend the antenna's operating bandwidth. The metal frame is mainly used to extend the antenna's 3dB beamwidth. The four-port excitation method helps improve the axial ratio of the circularly polarized antenna element.

[0036] To verify the advantages of the broadband circularly polarized antenna proposed in this application embodiment, the relevant indicators are verified below.

[0037] Currently, mainstream satellite communication phased array antennas primarily cover a scanning angle range of ±60°. However, in scenarios with larger scanning angles such as ±85°, performance indicators like axial ratio deteriorate rapidly, necessitating modifications to antenna element specifications. Without loss of generality, let's take an existing L-band microstrip patch circularly polarized antenna element as an example, such as... Figure 2 As shown, due to the narrow bandwidth of the microstrip antenna, this microstrip patch circularly polarized antenna consists of relatively independent receiving and transmitting antennas. The receiving antenna operates in the frequency band R_L~R_H, with an intermediate frequency of R_M, while the transmitting antenna operates in the frequency band T_L~T_H, with an intermediate frequency of T_M. The axial ratio of its azimuth plane at phi=0° varies with the elevation angle as shown in Table 1.

[0038] Table 1. Axial ratio of microstrip antenna elements as a function of elevation angle

[0039] As shown in Table 1, the microstrip antenna element has poor axial ratio performance and narrow bandwidth, and its axial ratio balance within the elevation angle ±85° is also poor.

[0040] The axial ratio of the azimuth plane with phi=0° of the width circularly polarized antenna proposed in this application varies with the elevation angle as shown in Table 2.

[0041] Table 2. Variation of axial ratio of broadband circularly polarized antenna elements with elevation angle

[0042] Comparing Tables 1 and 2, it can be seen that the wide circularly polarized antenna proposed in this application has good and smooth axial ratio performance across the entire bandwidth and within ±85° elevation angles. The performance at 85° elevation angle and -85° elevation angle is very consistent, providing a good foundation for array antennas.

[0043] This embodiment uses an L-band satellite communication antenna as an example only, and does not mean that this application is only applicable to L-band satellite communication antennas, but is suitable for satellite communication antennas of all frequency bands.

[0044] To better illustrate the design of the width-circularly polarized antenna in this application, several implementation methods of the width-circularly polarized antenna are given below.

[0045] Example 1 Please refer to Figure 3 , Figure 4 In this embodiment, the broadband circularly polarized antenna mainly includes a feed network, a feed plate, a radiator, a metal frame, and a metal base plate. The feed network transmits signals and is directly connected to or electromagnetically coupled to the feed plate. A coupling feed region is formed between the feed plate and the radiator, through which the feed plate electromagnetically feeds the radiator. The metal frame is disposed on the metal base plate, surrounding the feed network, feed plate, and radiator. The metal base plate serves as the reference ground for the radiator. The metal frame is directly connected to or electromagnetically coupled to the metal base plate.

[0046] The broadband circularly polarized antenna includes four feed plates, which respectively form four coupled feed regions with the radiator; the feed network is divided into four paths, which are directly connected to the four feed plates or electromagnetically coupled to them respectively.

[0047] Please continue to refer to this. Figure 4 The radiator of this broadband circularly polarized antenna is located above the feed plate, while the metal frame is lower than both the radiator and the feed plate. It should be noted that in actual implementation, there are no special requirements regarding the height of the radiator, feed plate, and metal frame; that is, the radiator can be above, below, or on the same plane as the feed plate; the height of the metal frame can be higher, lower, or the same as the height of the radiator or feed plate.

[0048] Example 2 Please refer to Figure 5 , Figure 6In this embodiment, the broadband circularly polarized antenna mainly includes a feed network, a feed plate, a radiator, a metal frame, and a metal base plate. The feed network is directly connected to the feed plate or electromagnetically coupled to it. A coupling feed region is formed between the feed plate and the radiator, and the feed plate electromagnetically feeds the radiator through this region. The metal frame is disposed on the metal base plate, surrounding the feed network, feed plate, and radiator. The metal base plate serves as the reference ground for the radiator. The metal frame is directly connected to the metal base plate or electromagnetically coupled to it.

[0049] Please continue to refer to this. Figure 5 , Figure 6 Compared to Embodiment 1, the broadband circularly polarized antenna of this embodiment includes a first layer of radiators and a second layer of radiators, as well as a first layer of feed plates and a second layer of feed plates. Both the first and second layer of feed plates include four feed plates, and the feed plates and radiators are alternately arranged. Please refer to... Figure 6 The first layer of feed plate, the first layer of radiator, the second layer of feed plate, and the second layer of radiator are arranged sequentially from top to bottom. The four feed plates of the first and second layers of feed plates are arranged coaxially to receive four signals fed into the feed network.

[0050] This embodiment only uses a two-layer radiator and feed plate as an example. In actual implementation, the radiator or feed plate can be one or more layers. In this embodiment, the metal frame is lower than the radiator and feed plate. In actual implementation, similar to Embodiment 1, there are no special requirements on the height of the radiator, feed plate, and metal frame. That is, the radiator can be above the feed plate, below the feed plate, or both can be on the same plane; the height of the metal frame can be higher than the radiator or feed plate, lower than the radiator or feed plate, or the same as the height of the radiator or feed plate.

[0051] Example 3 Please refer to Figure 7 , Figure 8 In this embodiment, the broadband circularly polarized antenna mainly includes a feed network, a feed plate, a radiator, a metal frame, and a metal base plate. The feed network transmits signals and is directly connected to the feed plate or electromagnetically coupled to it. A coupling feed region is formed between the feed plate and the radiator, and the feed plate electromagnetically feeds the radiator through this coupling feed region. The metal frame is disposed on the metal base plate, surrounding the feed network, feed plate, and radiator. The metal base plate serves as the reference ground for the radiator. The metal frame is directly connected to the metal base plate or electromagnetically coupled to it.

[0052] The broadband circularly polarized antenna includes four feed plates and four slots on the edge of the radiator. The four feed plates and the four slots respectively form four coupled feed regions. The feed network is divided into four paths and connected to the four feed plates respectively. Compared with the antenna of Embodiment 1, in this embodiment, the coupled feed regions are located at the edge of the radiator, and the feed plates feed the radiator from the edge of the radiator through the coupled feed regions.

[0053] Please continue to refer to this. Figure 8 In this embodiment, the radiator is above the feed plate, and the metal frame is lower than both the radiator and the feed plate. In actual implementation, there are no special requirements on the height of the radiator, the feed plate, and the metal frame; that is, the radiator can be above the feed plate, below the feed plate, or both can be on the same plane; the height of the metal frame can be higher than the radiator or the feed plate, lower than the radiator or the feed plate, or the same as the height of the radiator or the feed plate.

[0054] Example 4 Please refer to Figure 9 , Figure 10 In this embodiment, the broadband circularly polarized antenna mainly includes a feed network, a feed element, a radiator, a metal frame, and a metal base plate. The feed network transmits signals and is connected to the feed element. A coupling feed region is formed between the feed element and the radiator, and the feed element electromagnetically couples to the radiator through this region. The metal frame is disposed on the metal base plate, surrounding the feed network, feed element, and radiator. The metal base plate serves as the reference ground for the radiator. The metal frame and the metal base plate are directly connected or electromagnetically coupled together.

[0055] Please continue to refer to this. Figure 9 The radiator comprises four independent sub-radiators that are not directly electrically connected, forming four feed plates that create a coupled feed region with each independent sub-radiator. Then, the feed network, via the feed plates and the coupled feed region, completes the coupled feed of the radiator.

[0056] In this embodiment, the radiator is above the feed plate, and the metal frame is below both the radiator and the feed plate. In actual implementation, there are no special requirements on the height of the radiator, feed plate, and metal frame; that is, the radiator can be above the feed plate, below the feed plate, or both can be on the same plane; the height of the metal frame can be higher than the radiator or the feed plate, lower than the radiator or the feed plate, or the same as the height of the radiator or the feed plate.

[0057] The present invention can be well implemented through the above embodiments.

[0058] It should be noted that, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances. The accompanying drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0059] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A broadband circularly polarized antenna, characterized in that, The device includes a power supply network, a power supply plate, a radiator, a metal frame, and a metal base plate. The power supply network is used to transmit signals and is connected to the power supply plate. A coupling power supply region is formed between the power supply plate and the radiator, and the power supply plate electromagnetically couples and powers the radiator through this region. The metal frame is mounted on the metal base plate and surrounds the power supply network, the power supply plate, and the radiator. The metal base plate serves as the reference ground for the radiator.

2. The broadband circularly polarized antenna according to claim 1, characterized in that, The metal frame is directly connected to the metal base plate or electromagnetically coupled to it.

3. The broadband circularly polarized antenna according to claim 1, characterized in that, The power supply network is directly connected to the power supply plate or electromagnetically coupled to it.

4. The broadband circularly polarized antenna according to claim 1, characterized in that, The broadband circularly polarized antenna includes four feed plates, which form four coupled feed regions with the radiator. The feed network is divided into four paths, which are directly connected to or electromagnetically coupled to the four feed plates respectively.

5. The broadband circularly polarized antenna according to claim 1, characterized in that, The power supply network is implemented using metal pillars or transmission lines.

6. The broadband circularly polarized antenna according to claim 4, characterized in that, The projections of the four coupled feeding regions are located inside or at the edge of the radiator.

7. The broadband circularly polarized antenna according to claim 1, characterized in that, The radiator comprises four independent sub-radiators that are not directly electrically connected.

8. The broadband circularly polarized antenna according to any one of claims 4, 6, or 7, characterized in that, The four input signals in the power supply network have equal amplitudes or a maximum amplitude difference of less than 6dB, and their phases differ by 90° or 90°±30° in a clockwise or counterclockwise direction.

9. The broadband circularly polarized antenna according to claim 1, characterized in that, The broadband circularly polarized antenna includes one or more radiators and feed plates. When multiple radiators and feed plates are included, each radiator and feed plate are alternately arranged vertically, and each feed plate is coaxially arranged.

10. The broadband circularly polarized antenna according to claim 1, characterized in that, The broadband circularly polarized antenna is suitable for satellite communication antennas in all frequency bands.

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