Dual-polarized band-pass three-dimensional frequency selective surface with bilateral steep drop characteristic

Abstract

The invention discloses a dual-polarized band-pass three-dimensional frequency selective surface with a bilateral steep drop characteristic. The frequency selective surface is formed by periodically arranging a plurality of identical unit structures, and each unit structure is composed of three layers. The outermost layer is a medium square cylinder; the middle layer is a metal square cylinder; the innermost layer is a medium square block, a metal square ring is etched on each of the upper surface and the lower surface of the medium square block respectively, and the two metal square rings arethe same in size and are axially-symmetrically distributed up and down. The two metal square rings are electromagnetically coupled through the medium square block, a single resonance mode is split into an odd mode resonance mode and an even mode resonance mode, two transmission poles are generated, and therefore a flat passband is formed. Due to the fact that three transmission zeros are generated through signal phase reversal and electromagnetic coupling in the outermost medium square cylinder and the innermost medium square block, the frequency selective surface has the characteristic of bilateral steep drop, the frequency selective performance is improved, and meanwhile the frequency selective surface has good angle stability in a dual-polarization working mode.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic fields and microwaves, and in particular relates to a dual-polarization bandpass three-dimensional frequency selective surface with double-sided steep drop characteristics. Background technique [0002] Frequency Selective Surface (FSS) is usually a two-dimensional array structure composed of periodic units with a specific shape, and has the function of a spatial filter. Under the irradiation of electromagnetic waves, FSS itself does not absorb electromagnetic waves, but it will generate resonance phenomenon at a certain frequency. At this time, the transmission field or reflection field is the largest, which can effectively transmit or reflect electromagnetic waves. Therefore, FSS can be roughly divided into There are two types of bandpass and bandstop. In recent decades, FSS has been widely used in the fields of spatial filtering, radomes, electromagnetic shielding, reflectors, and abso...

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Problems solved by technology

The traditional two-dimensional FSS structure can realize bandpass FSS through various methods such as metal patches, metal rings, metal strip lines, slots, etc., but often can only introduce transmission zeros on one side of the passband, so it is difficult to achieve both sides of the passband Steep drop performance; later researchers adopted a multi-layer stacking method. Although transmission zeros were introduced on both sides of the passband, the bilateral steep drop performance of the passband was realized, and its frequency selectivity was well improved. However, the multilayer stack The method leads to the increase of the electrical size and thickness of the entire FSS unit structure, thus affecting the angular stability of the FSS, and it is difficult to carry out practical application in the communication system

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