A series-fed microstrip antenna

Abstract

This invention provides a series-fed microstrip antenna, belonging to the field of radar antenna technology. It includes a substrate and multiple antenna elements arranged in arrays on the substrate. Each antenna element includes a feed microstrip line, multiple series-fed antennas, and multiple couplers corresponding to the series-fed antennas. The feed microstrip line, series-fed antennas, and couplers are all disposed on the same surface of the substrate. The multiple series-fed antennas are all located on the same side of the feed microstrip line and are arranged sequentially along the length of the feed microstrip line. The couplers have cavities, and the ends of the series-fed antennas furthest from the feed microstrip line enter the corresponding cavities of the couplers. The spacing between the feed microstrip lines of two adjacent antenna elements is less than or equal to half the air wavelength. The series-fed microstrip antenna provided by this invention shifts the maximum beam pointing of the antenna and reduces additional insertion loss, effectively improving the antenna's radiation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of radar antenna technology, and more specifically, relates to a series-fed microstrip antenna. Background Technology

[0002] Microstrip antennas are widely used in radar due to their advantages of small size, light weight, low profile, conformal capability, and ease of integration. Compared to traditional microstrip antennas, series-fed microstrip antennas have a more compact feed network, are easier to integrate, and are easier to achieve narrow beams and high gains. Compared to parallel-fed antennas, series-fed antennas have a more compact structure and shorter feed lines, resulting in lower losses.

[0003] Traditional series-fed microstrip antennas, having only one antenna element, have a maximum beam pointing along the normal to the antenna substrate, with a 3dB beamwidth of approximately 70°–80°. To change the maximum beam pointing angle, current technologies typically employ multiple series-fed microstrip antennas combined into an array antenna, along with a relatively complex feeding network, to alter the maximum beam pointing and broaden the 3dB beamwidth. However, this method incurs additional insertion loss, reducing the antenna's radiation efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a series-fed microstrip antenna to solve the technical problems of existing series-fed microstrip antennas, such as easy generation of additional insertion loss and low radiation efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A series-fed microstrip antenna is provided, comprising a substrate and multiple antenna elements arranged in an array on the substrate. Each antenna element includes a feed microstrip line, multiple series-fed antennas, and multiple coupling elements corresponding to the series-fed antennas. The feed microstrip line, the series-fed antennas, and the coupling elements are all disposed on the same surface of the substrate. The multiple series-fed antennas are all located on the same side of the feed microstrip line and are arranged sequentially along the length of the feed microstrip line. A cavity is provided on each coupling element, and the end of each series-fed antenna away from the feed microstrip line is respectively housed in the cavity of the corresponding coupling element. The spacing between the feed microstrip lines of two adjacent antenna elements is less than or equal to half the air wavelength.

[0006] In one possible implementation, a plurality of the series-fed antennas are arranged in a Taylor distribution on the substrate.

[0007] In one possible implementation, a plurality of the series-fed antennas are arranged sequentially at intervals along the length direction of the feed microstrip line.

[0008] In one possible implementation, the multiple series-fed antennas are fed in equal phase and spaced 0.75 times the air wavelength.

[0009] In one possible implementation, the series-fed antenna is a rectangular metal patch.

[0010] In one possible implementation, there are eight rectangular metal patches.

[0011] In one possible implementation, the coupling element is a C-shaped structure, and the series-fed antenna enters the cavity from the opening of the C-shaped structure.

[0012] In one possible implementation, a ground layer is provided on another surface of the substrate.

[0013] In one possible implementation, the grounding layer is a metal plate covering another side of the substrate.

[0014] In one possible implementation, the substrate is a high-frequency microwave board material.

[0015] The beneficial effects of the series-fed microstrip antenna provided by this invention are as follows: Compared with the prior art, the series-fed microstrip antenna of this invention arranges multiple antenna elements in an array on a substrate, and the multiple series-fed antennas on each antenna element are sequentially arranged on the corresponding feed microstrip lines, which reduces the additional insertion loss introduced by the series-parallel combined feed network and effectively improves the radiation efficiency of the antenna. At the same time, the multiple series-fed antennas are located on the same side of the feed microstrip lines, which causes the beam pointing of the antenna to be shifted. Couplers connected to each series-fed antenna are provided on the substrate, and the couplers play a guiding role, which further shifts the beam pointing of the antenna. The distance between two adjacent feed microstrip lines is less than or equal to half the air wavelength. In this way, the maximum beam pointing of the antenna is shifted, and additional insertion loss is reduced, effectively improving the radiation efficiency of the antenna. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the antenna unit provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a series-fed microstrip antenna provided in an embodiment of the present invention.

[0019] The following are the labeling elements in the figure:

[0020] 1. Substrate; 2. Feed microstrip line; 3. Series-fed antenna; 4. Coupler; 5. Grounding layer. Detailed Implementation

[0021] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0022] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0023] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] Please see Figure 1 and Figure 2 The following describes the series-fed microstrip antenna provided by the present invention. A series-fed microstrip antenna includes a substrate 1 and multiple antenna elements arranged in an array on the substrate 1. Each antenna element includes a feed microstrip line 2, multiple series-fed antennas 3, and multiple coupling elements 4 corresponding one-to-one with each series-fed antenna 3. The feed microstrip line 2, the series-fed antennas 3, and the coupling elements 4 are all disposed on the same surface of the substrate 1. The multiple series-fed antennas 3 are all located on the same side of the feed microstrip line 2, and are arranged sequentially along the length of the feed microstrip line 2. The coupling elements 4 have cavities, and the ends of the series-fed antennas 3 away from the feed microstrip line 2 are respectively housed in the cavities of the corresponding coupling elements 4. The spacing between the feed microstrip lines 2 of two adjacent antenna elements is less than or equal to half the air wavelength.

[0026] The series-fed microstrip antenna provided by this invention, compared with the prior art, arranges multiple antenna elements on a substrate 1, and multiple series-fed antennas 3 on each antenna element are sequentially arranged on the corresponding feed microstrip line 2. This reduces the additional insertion loss introduced by the series-parallel combined feed network and effectively improves the radiation efficiency of the antenna. At the same time, the multiple series-fed antennas 3 are located on the same side of the feed microstrip line 2, which causes the antenna beam pointing to be shifted. Couplers 4 connected to each series-fed antenna 3 are provided on the substrate 1. The couplers 4 play a guiding role, which further shifts the antenna beam pointing. The spacing between two adjacent feed microstrip lines 2 is less than or equal to half the air wavelength. In this way, the maximum beam pointing of the antenna is shifted, and additional insertion loss is reduced, effectively improving the radiation efficiency of the antenna.

[0027] By grounding the coupler 4 and adjusting its position and length, the direction of the maximum beam can be changed. Combined with the coupler 4, which has a directing function, this series-fed microstrip antenna can be used as a millimeter-wave antenna element. Test results show that the maximum beam pointing at 38° has a 6dB beamwidth of approximately 155°. Furthermore, due to its simple feeding method, it can be arrayed using half the air wavelength. Figure 2 In this context, d represents the spacing between the feed microstrip lines 2 of two adjacent antenna elements, and the value of d is less than or equal to half the air wavelength.

[0028] For radars capable of full-space angle measurement, to ensure a theoretical angle measurement range of ±90°, the spacing between antenna elements generally needs to be less than or equal to half the air wavelength. This precludes using array antennas with dimensions much larger than half the wavelength as receiving antennas. Currently, the only feasible compromise in wide-beam angle measurement radars is to use an array antenna with the beam pointing off-phase as the transmitting antenna, while using a traditional single-string microstrip antenna with the beam pointing to the normal phase as the receiving antenna.

[0029] Please see Figure 1 As a specific embodiment of the series-fed microstrip antenna provided by the present invention, multiple series-fed antennas 3 are arranged in a Taylor distribution on the substrate 1; the Taylor distribution is used to reduce the beam sidelobe level in the antenna array direction and improve the performance of the series-fed microstrip antenna.

[0030] Please see Figure 1 As a specific embodiment of the series-fed microstrip antenna provided by the present invention, multiple series-fed antennas 3 are arranged sequentially at intervals along the length direction of the feed microstrip line 2. Therefore, two adjacent series-fed antennas 3 will not affect each other, and no interference will occur when the coupling element 4 is installed.

[0031] Preferably, please refer to Figure 1As a specific embodiment of the series-fed microstrip antenna provided by the present invention, multiple series-fed antennas 3 are fed in equal phase and the spacing is 0.75 times the air wavelength; multiple series-fed antennas 3 are distributed on the same side, and are set and fed in equal phase, and the spacing is three-quarters of the air wavelength.

[0032] Optionally, please refer to Figure 1 The series-fed antenna 3 is a rectangular metal patch.

[0033] Optionally, please refer to Figure 1 There are 8 rectangular metal patches.

[0034] Please see Figure 1 In one specific embodiment of the series-fed microstrip antenna provided by the present invention, the coupler 4 has a C-shaped structure, and the series-fed antenna 3 enters the cavity from the opening of the C-shaped structure; the opening of the C-shaped structure faces the series-fed antenna 3, and the upper end of the series-fed antenna 3 enters the C-shaped structure. With the guiding effect of the coupler 4, the beam direction of the antenna is further shifted. This C-shaped coupler 4 has a simple structure, is easy to install, and has high operational reliability.

[0035] Please see Figure 1 As a specific embodiment of the series-fed microstrip antenna provided by the present invention, a ground layer 5 is provided on the other side of the substrate 1, and a grounding point is introduced through the ground layer 5; the series-fed microstrip antenna of this application has a ground layer 5, but it can also be a series-fed microstrip antenna without a ground layer. Preferably, the ground layer 5 is a metal plate, and the metal plate covers the other side of the substrate 1.

[0036] Please see Figure 1 As a specific embodiment of the series-fed microstrip antenna provided by the present invention, the substrate 1 is a high-frequency microwave board material. The substrate 1 is made of a high-frequency microwave board material with high electromagnetic stability to improve the working performance of the substrate 1.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A series-fed microstrip antenna, characterized in that, The device includes a substrate and multiple antenna elements arranged in arrays on the substrate. Each antenna element includes a feed microstrip line, multiple series-fed antennas, and multiple couplers corresponding to the series-fed antennas. The feed microstrip line, the series-fed antennas, and the couplers are all disposed on the same surface of the substrate. The multiple series-fed antennas are all located on the same side of the feed microstrip line and are arranged sequentially along the length of the feed microstrip line. Each coupler has a cavity, and the ends of the series-fed antennas away from the feed microstrip line are respectively housed in the cavities of the corresponding couplers. The spacing between the feed microstrip lines of two adjacent antenna elements is less than or equal to half the air wavelength; The coupling element is a C-shaped structure, and the series-fed antenna enters the cavity from the opening of the C-shaped structure. The opening of the C-shaped structure faces the series-fed antenna, and the upper end of the series-fed antenna enters the C-shaped structure. The guiding effect of the coupling element deflects the beam direction of the antenna.

2. The series-fed microstrip antenna as described in claim 1, characterized in that, Multiple series-fed antennas are arranged in a Taylor distribution on the substrate.

3. The series-fed microstrip antenna as described in claim 1, characterized in that, Multiple series-fed antennas are arranged sequentially at intervals along the length of the feed microstrip line.

4. The series-fed microstrip antenna as described in claim 3, characterized in that, The multiple series-fed antennas are fed in equal phase and spaced 0.75 times the air wavelength.

5. The series-fed microstrip antenna as described in claim 1, characterized in that, The series-fed antenna is a rectangular metal patch.

6. The series-fed microstrip antenna as described in claim 5, characterized in that, There are 8 rectangular metal patches.

7. The series-fed microstrip antenna as described in claim 1, characterized in that, A grounding layer is provided on the other side of the substrate.

8. The series-fed microstrip antenna as described in claim 7, characterized in that, The grounding layer is a metal plate that covers another side of the substrate.

9. The series-fed microstrip antenna as described in claim 1, characterized in that, The substrate is a high-frequency microwave board material.

Images