Convex Conformal Cassegrain Antenna Based on Metasurface

Abstract

The invention discloses a metasurface-based convex conformal cassegrain antenna, and mainly aims to solve the problems that the existing antenna is high in phase error, complex in structure, and hardto realize convex cassegrain beam calibration. The metasurface-based convex conformal cassegrain antenna comprises a carrier (1), a main reflecting mirror (2), an auxiliary reflecting mirror (3), a feed source (4) and a supporting structure (5); the carrier adopts a convex structure; the main reflecting mirror is conformal with the carrier; each of the main reflecting mirror and the auxiliary reflecting mirror adopts a phase change metasurface structure established based on generalized Snell law, wherein the auxiliary reflecting mirror is located below the focal point of the main reflecting mirror and has a hyperbolic characteristic phase, and is used for dispersing the electromagnetic waves emitted by the feed source into spherical waves, wherein the virtual focal point of the auxiliary reflecting mirror coincides with the focal point of the main reflecting mirror, and the solid focal point coincides with the phase center of the feed source; and the supporting structure is connected with the main reflecting mirror and the auxiliary reflecting mirror. By virtue of the metasurface-based convex conformal cassegrain antenna, wave beam calibration of the convex cassegrain antenna can be realized; and meanwhile, the antenna phase compensation error is lowered, the structure is simple, and the antenna can be used for communication and radar.

Description

technical field [0001] The invention belongs to the technical field of antennas, and relates to a Cassegrain antenna, which can be used for communication and radar. [0002] technical background [0003] Microwave antennas are mainly divided into end-fire, slot, reflector antennas and other types, among which the reflector antenna has the characteristics of high gain performance. The microwave reflector antenna is mainly a parabolic antenna, which uses the collimation effect of the parabolic reflector to convert the spherical wavefront emitted from the feed source at the focal point into an outgoing plane wavefront to form a high-gain pattern. The Cassegrain antenna adds a hyperboloid secondary reflector to the parabolic antenna. Electromagnetic waves are reflected by the secondary reflector and the main reflector to obtain a highly directional radiation pattern. It has been widely used in communications and radar. Compared with the ordinary parabolic antenna, the added sub-...

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Problems solved by technology

[0005] First of all, the phase compensation method of this antenna is that the electromagnetic wave passes through the metamaterial twice successively, and the wavefront calibration is performed by using the different constitutive parameters of the metamaterial on the propagation path and the different electrical wavelength changes at the same physical distance. The premise of the phase path design of the material layer is to assume that the electromagnetic wave is vertically incident on the reflective surface, and does not consider the change of the incident angle when the electromagnetic wave is obliquely incident, there is a large phase compensation error, and the phase error increases with the increase of the incident angle ;

[0006] Secondly, since the phase compensation of the reflected wavefront of this antenna is based on the fact that the electromagnetic wave passes through the metamaterial layer twice, the degree of matching between the metamaterial and free space is different for different electromagnetic parameters, so the matching between the metamaterial layer and free space The problem will also affect the wavefront calibration results of the antenna, and the resulting phase compensation error will further increase;

[0007] Thirdly, since the required metamaterials of this antenna are realized by loading metal microstructures in the multilayer dielectric plate, not only the structure is more complex, but also the problem of beam alignment of the convex mirror that conforms to the carrier cannot be solved, and the phase error is relatively large

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