基于椭圆形谐振器的宽带频率选择吸波器

Wideband Frequency Selective Rasorber Using Elliptical Resonators

摘要:

提出了一种基于椭圆形缝隙谐振结构的宽透波带频率选择吸波器（frequency-selective rasorber，FSR）。该吸波器由损耗层和二阶带通频率选择表面（frequency-selective surface，FSS）两层结构组成。损耗层以耶路撒冷十字形为基础结构，四个椭圆环内嵌有椭圆贴片，共同构成谐振器，从而实现宽带透波特性。损耗层底部中央涂覆石墨烯作为损耗结构，以实现对电磁波的吸收。FSS层采用三层金属和两层介质的对称结构，实现了宽通带和陡峭的滚降特性。通过构建的等效电路模型对该双层结构的工作原理进行了分析，并分析了不同极化及不同入射角下FSR电磁响应的稳定性。仿真结果表明：该FSR在9.3~10.7 GHz频段内实现了插入损耗在1 dB以内的宽带透波特性，并在通带以下展现出宽频带吸波性能。

Abstract:

A wide transmission band frequency-selective rasorber (FSR) based on elliptical slot resonant structure was presented. The structure consisted of a lossy layer and a second-order bandpass frequency-selective surface (FSS). The lossy layer was based on a Jerusalem cross structure, which incorporated four elliptical rings and four elliptical patches to generate resonance and provide a broad wave-transparent band. Graphene was coated at the bottom center of the lossy layer to serve as a lossy material. The FSS employed a symmetric configuration comprising three metal layers and two dielectric substrates, achieving a wide passband and sharp roll-off characteristics. The operational principle was analyzed by means of an equivalent circuit model (ECM). Furthermore, the stability of the FSR electromagnetic response under different polarization and incident angles was analyzed. Simulation results demonstrate that a 1-dB bandwidth of 9.3-10.7 GHz is achieved and a wide absorption band below the passband is exhibited.