CN110890629B

CN110890629B - All-metal multi-beam lens antenna with low profile and wide angle scanning

Info

Publication number: CN110890629B
Application number: CN201911279379.3A
Authority: CN
Inventors: 杨仕文; 刘坤宁; 黄明; 屈世伟; 陈益凯; 胡俊
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2020-07-28
Anticipated expiration: 2039-12-12
Also published as: CN110890629A

Abstract

The invention discloses an all-metal multi-beam lens antenna with a low section and wide angle scanning, which realizes the beam scanning of an azimuth plane of 126 degrees and the wide beam of which a pitching plane is more than 60 degrees. The lens antenna designed by the scheme realizes the single mode transmission of a TEM mode between parallel plate waveguides, and the section height of the lens antenna can be limited to be within a half wavelength range, so that the lens antenna has the advantages of low section, low manufacturing cost, small volume, easy integration and convenient engineering realization, and is particularly suitable for millimeter wave frequency bands and application scenes needing axial array.

Description

All-metal multi-beam lens antenna with low profile and wide angle scanning

Technical Field

The invention relates to a lens antenna belonging to the technical field of antenna engineering, in particular to an all-metal multi-beam lens antenna with low section and wide angle scanning for multi-beam directional communication, which is particularly suitable for various application scenes such as vehicle-mounted, airborne, ship-based, base stations and small stations, and has the advantages of low manufacturing cost, small volume, easy integration and high structural strength.

Background

Along with the increasing and wider requirements of the technical fields of satellite communication, electronic countermeasure, target tracking and the like on the multi-beam communication antenna, correspondingly, the electrical performance requirements of the multi-beam communication antenna are also increased, the requirements of high gain, narrow beam, low side lobe, wide beam coverage and the like are met, meanwhile, the requirements of manufacturing cost, application environment universality and the like are also considered, and particularly in the millimeter wave frequency band, the dielectric loss of the dielectric lens antenna is too large, and the manufacturing cost of the processing technology is high, so that the dielectric lens antenna is difficult to be generally applied. Based on the application requirements, the invention designs the all-metal multi-beam lens antenna with low profile and wide angle scanning.

The method is characterized in that a Lunebyon et al does not consider the mechanical strength of materials and is difficult to be used in engineering, and a Lunebuild et al proposes a multibeam dielectric cylinder lens antenna in a CN 102176538, wherein although a dielectric cylinder with certain strength is filled between parallel plates to support the parallel plates, the multibeam dielectric cylinder antenna is difficult to be completely stabilized even if high-strength adhesive is excessively used between the metal parallel plates and non-metal media, and the stabilizing of the parallel plates and the dielectric cylinder lens can not cause a certain degree of serious stress in the horizontal direction under high-vibration working scenes of vehicle loading, load loading and the like, so that the working performance of the antenna is influenced, and the working efficiency of the antenna is not increased by using a carrier wave antenna, and the like, so that the antenna is not more than that of a millimeter wave cylinder antenna in a street lamp antenna, and the millimeter wave scanning equivalent plane antenna, and the millimeter wave scanning equivalent antenna has no problem that the reflector antenna is not increased by using a reflector lens in a street lamp antenna.

Disclosure of Invention

In view of the above background and requirements, the present invention provides an all-metal multi-beam lens antenna with low profile and wide angle scanning. The lens part of the antenna is formed by two metal parallel plates, the inner sides of the two metal plates are respectively processed by ridge adding or groove opening, the two metal plates are not contacted with each other by air filling, and the distance between the two metal plates is kept small enough to ensure the single-mode transmission (TEM mode) of electromagnetic waves between parallel plate waveguides in the form of surface waves. Meanwhile, the epitaxial part of the upper metal parallel plate is processed in an inward beveling shape, the thickness of the lens is transited to the height of the feed source antenna, the standing wave performance of the feed source antenna is well improved, and an effective metal fixing structure is added at the feed source array to increase the integral strength of the antenna. The single beam of the lens antenna is designed to have a central frequency of 28GHz, the beam width of a pitching plane of the directional diagram is larger than 60 degrees, the azimuth plane of the directional diagram is slightly larger than 7 degrees, and the coverage of a 126-degree beam on the azimuth plane can be realized by 18 feed sources.

The invention has the innovation points that the electromagnetic wave in a TEM mode can be transmitted between the parallel plate waveguides in a single mode, the thickness of the parallel plate waveguides is restricted below half wavelength, the shape of the inner side of the parallel plate waveguides in the air-filled all-metal lens and the section height of the whole lens are greatly simplified, and meanwhile, the good focusing performance of the lens antenna is ensured. Therefore, the invention provides a lens antenna realizing idea with miniaturization and simple structure while ensuring the electrical performance of the traditional lens antenna.

The invention has another characteristic that a micro-strip feed source antenna form with compact structure is adopted instead of a gradual change slotted antenna form, and the micro-strip feed source antenna is fixed on the metal arc aluminum plate positioned on the back of each micro-strip patch feed source antenna, so that the structural strength and the system integration level of the antenna are increased, and the integrated realization in engineering is also facilitated.

The electromagnetic wave radiated by the microstrip patch feed source antenna enters an air-filled all-metal lens, and finally exits in a plane wave form through different optical paths in the lens under the limiting action of a metal parallel plate waveguide, azimuth plane wave beams are converged to form narrow wave beams, 18 wave beams can be formed by sequentially feeding 18 feed source antennas in an arc array, and adjacent wave beams are overlapped at a point of 3dB, and the coverage of the azimuth plane wave beams of 126 degrees can be realized by the 18 wave beams because the width of each wave beam is 7 degrees and the azimuth plane wave beams of 18 wave beams are overlapped.

Drawings

FIG. 1 is a three-dimensional block diagram of a lens antenna of the present invention;

FIG. 2 is a top structure view of a metal parallel plate of the lens antenna of the present invention;

FIG. 3 is a lower structure view of a metal parallel plate of the lens antenna of the present invention;

FIG. 4 is a top plan view and a side sectional view of the lens antenna of the present invention;

FIG. 5 is an S parameter for two exemplary ports when feed antennas of the lens antenna of the present invention are separately excited;

fig. 6 shows that 18 feeds sequentially excite 18 beams formed in an azimuth plane at 28GHz of the lens antenna of the invention.

FIG. 7 is a pitch plane radiation pattern for a single feed excitation for a lens antenna of the present invention at 28 GHz;

detailed description of the preferred embodiments

The design structure diagram of the all-metal multi-beam lens antenna with low section and wide angle scanning is described in detail in fig. 1, fig. 2, fig. 3 and fig. 4. according to the figure, the device mainly comprises an upper metal parallel plate layer 1, a lower metal parallel plate layer 2, an arc-shaped array 3 consisting of 18 micro-strip feed source antennas and a metal screw 4 for fixing the upper metal parallel plate layer 1 and the lower metal parallel plate layer 2 in the all-metal lens antenna, wherein the maximum caliber size of the lens antenna is 122 × 5mm²Focal length of feed from lensAnd 5mm, the spacing between the upper metal parallel layer 1 and the lower metal parallel plate layer 2 is chosen to be 1.5mm, much smaller than the wavelength at the design center frequency of 28 GHz. Common lens antenna feed sources are mainly divided into two feed source antennas in the form of horn antenna type aperture antennas and planar microstrip antennas. Common forms of horn-type aperture feed source antennas include common horns, corrugated horns, dielectric waveguide feed sources, and the like. However, such a feed source is often large in size and weight, occupies too much space and load, has a large challenge in implementation of a fixing method, and is not favorable for use in some portable devices and under the condition of strict requirements of use scenes. Feed antennas of the planar microstrip patch type. Such antennas consist of a dielectric sheet on which a metal-deposited rectangular, circular or other geometric shape is used as the radiating structure, and on the back of which a metal plate is used as the ground plane. The radiating structure may be fed with microstrip or coaxial lines. The microstrip antenna has the main advantages of light weight, low profile, easy conformal and low cost as a feed source structure; the electrical performance is good, and the patterns on both main surfaces are wide and stable in ripple. The microstrip antenna is used as a feed source of the cylindrical lens antenna, so that the antenna is compact as a whole and miniaturized.

Based on the advantages and disadvantages of the above two forms of feed sources, the present document designs a miniaturized E-shaped microstrip patch antenna as a feed source after comprehensively considering the aspects of cost, main performance requirements of the antenna, design complexity, system integration level, etc. In order to ensure that the arc array 3 consisting of the 18 microstrip feed source antennas can be accurately and stably placed between the upper layer 1 of the two layers of metal parallel plates and the lower layer 2 of the metal parallel plates, the corresponding position of the upper layer 1 of the metal parallel plate is also slotted (as shown in figure 3), and a fixed metal plate is added at the corresponding position of the lower layer 2 of the metal parallel plate for fixing (as shown in figure 4). Because the corresponding 3dB beam width of each microstrip patch is 7 degrees after being focused by the lens, in order to enable the radiation beam of each feed source to be overlapped after passing through the lens, the included angle of two adjacent antenna units is set to be 7 degrees, the feed source array with the arc-shaped structure generates required beams at different scanning angles, and finally the beam scanning of 126 degrees is realized on the azimuth plane. The upper part and the lower part of the lens are two mutually parallel metal plates which form a parallel plate waveguide structure, so that electromagnetic waves radiated by the micro-strip feed source generate narrow beams on an azimuth plane after being focused by the lens, and adjacent beams are overlapped at a 3dB point. The lens antenna is fixed between an upper layer 1 and a lower layer 2 of a metal parallel plate by a metal screw 4, the inner side of the upper layer 1 of the metal parallel plate is grooved at the position corresponding to a convex circular ridge of the lower layer 2 of the metal parallel plate, so that electromagnetic waves can be conveniently transmitted between parallel plate waveguides with the same thickness, and the distance between the position of the groove and the ridge is 1.5 mm. The all-metal lens antenna designed by the scheme realizes high strength, vibration prevention and miniaturization, and also realizes the characteristic of high efficiency because the transmission medium of the electromagnetic waves in the lens is air.

FIG. 5 shows S parameters of a microstrip patch antenna feed in a lens antenna when the feed is excited respectively, because the lens antenna has high structural symmetry, two representative typical ports are selected for S parameter analysis, a port 1 represents an edge unit in a feed array, and a port 9 represents a center unit of the feed array, and it can be seen that S11 of the antenna feed port is less than-10 dB, S21 is less than-18 dB and the consistency is good in a working frequency band of 27-29 GHz.

Fig. 6 shows that the lens antenna of the invention has 18 feeds at 28GHz to sequentially excite 18 beams formed in the azimuth plane, and can realize beam scanning in the azimuth plane. The number of the micro-strip units in the arc-shaped array of the feed source is 18, the 3dB width of a wave beam formed on the azimuth plane by electromagnetic waves radiated by each feed source after being focused by the lens is about 7 degrees, adjacent wave beams are overlapped at 3dB points, the whole antenna can reach 126 degrees of wave beam coverage on the azimuth plane, and the gain displayed by an HFSS simulation result reaches 16.2 dB.

Fig. 7 is the radiation pattern of the pitching surface of a lens antenna based on the invention when excited by a single feed at 28GHz, and it can be seen that a wide beam is formed at the pitching surface, and HFSS simulation results show that the pitching surface 3dB lobe width is greater than 60 °.

The foregoing is a description of the invention and embodiments thereof provided to persons skilled in the art of the invention and is to be considered as illustrative and not restrictive. The engineer can perform the specific operation according to the idea of the claims of the invention, and naturally a series of modifications can be made to the embodiments according to the above description. All of which are considered to be within the scope of the present invention.

Claims

1. An all-metal multi-beam lens antenna with low section and wide angle scanning comprises a metal parallel plate upper layer (1), a metal parallel plate lower layer (2), an arc array (3) consisting of 18 micro-strip feed source antennas, and metal screws (4) for fixing the metal parallel plate upper layer (1) and the metal parallel plate lower layer (2); the upper layer (1) of the metal parallel plate is subjected to grooving treatment, the lower layer (2) of the metal parallel plate is subjected to ridge adding treatment, a metal fixing structure is added at the feed source array, the overall strength is improved, and the outer edge part of the upper layer (1) of the metal parallel plate is in an inward-chamfered shape.

2. The all-metal multi-beam lens antenna with low profile and wide angle scanning according to claim 1, characterized in that the arc array (3) composed of 18 microstrip feed antennas is arranged on the feed aperture of the lens antenna according to the circumference, so as to realize wide angle scanning with azimuth plane 126 ° and wide beam with elevation plane larger than 60 °.

3. The all-metal multi-beam lens antenna with the low profile and the wide angle scanning according to claim 1, further characterized in that a medium for the electromagnetic waves to propagate in the lens is a low-loss air medium, thereby realizing the design of a high-efficiency multi-beam lens antenna in a millimeter wave frequency band.