Dual-polarization three-order band-pass three-dimensional frequency selective surface

Abstract

The invention discloses a dual-polarization three-order band-pass three-dimensional frequency selective surface that is formed by periodically arranging a plurality of same unit structures. Each unitstructure includes a metal square cylinder and a dielectric square block. A metal square ring is etched at the central position of each of the upper surface, the middle layer and the lower surface ofthe dielectric square block. The metal square rings on the upper surface and the lower surface of the dielectric square block are the same in size and the perimeters of the two metal square rings arelarger than that of the metal square ring of the middle layer. Because of electromagnetic coupling between the resonance units on the upper surfaces and the lower surfaces of the unit structures, twotransmission poles are generated; the metal square rings of the middle layers, the metal square cylinders and the dielectric square blocks jointly act to form a third transmission pole, so that a flatthree-order passband is formed. Due to reverse offset of signal phases, three transmission zeros are introduced, so that the dual-polarization three-order band-pass three-dimensional frequency selective surface has high frequency selectivity wide out-of-band rejection and has high 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 third-order bandpass three-dimensional frequency selective surface. Background technique [0002] In the past few decades, Frequency Selective Surface (FSS) has been widely used in various microwave and millimeter wave systems due to its superior spatial filtering characteristics. FSS is usually a two-dimensional array composed of periodically arranged metal unit structures, which can achieve band-pass or band-stop filter response. Bandpass FSS requires flat transmission response and low insertion loss in the passband, while having high frequency selectivity and wide out-of-band rejection outside the band, and it should also have good angular stability, dual polarization, and small electrical size. [0003] The traditional second-order bandpass two-dimensional FSS can be realized by means of multilayer stack coupling...

AI Technical Summary

Problems solved by technology

[0003] The traditional second-order bandpass two-dimensional FSS can be realized by means of multi-layer stack coupling, etc., but there are often problems such as poor frequency selectivity, uneven passband, narrow out-of-band suppression bandwidth, and large electrical size.

Later, the team of Professor Shen Zhongxiang from Nanyang Technological University in Singapore proposed a series of second-order bandpass three-dimensional frequency selective surface structures based on shielded microstrip lines. The above problems have been effectively improved, but these structures can only achieve single polarization, which is largely limited. their practical application

Later, many scholars loaded the non-resonant unit in the middle layer of the multilayer structure, and used the electromagnetic coupling effect of the multilayer resonant unit to generate three or more transmission poles, realizing the third-order or higher-order bandpass FSS, and the passband The flatness has been improved, but these third-order or high-order bandpass FSS can only introduce a single transmission zero on one side of the passband or one transmission zero on both sides of the passband, and its frequency selectivity has been improved to a certain extent. But it is difficult to achieve wide out-of-band rejection

Images