Band-notch Absorber with Two-sided Absorption Bands and Two Reflection Bands

Abstract

In this work, a band-notch absorber with two reflection bands and two-sided absorption bands is proposed. The band-notch absorber is consisted of the up lossy layer and the bottom metal ground, which are separated by a substrate. The lossy layer is composed of multiple cascaded interdigital capacitors and four lumped elements. In the lossy layer, a wide high-transmission passband between two absorption bands can be realized by connecting multiple coplanar parallel resonances (MCPRs) in series which introduces a large impedance in a wide band. And the electromagnetic wave in the high-transmission band of the lossy layer will be reflected by the bottom metal ground layer, which forms a high-reflection band between the two absorption bands. Another reflection band occurs in a higher frequency range which is twice the frequency of the first reflection band. The simulation results show that the band-notch absorber can achieve two wide absorption bands which absorption rate are above 90% from 3.3 GHz to 7.78 GHz and from 12.8 GHz to 14.17 GHz. Moreover, the two high-reflection bands of the proposed band-notch absorber occur in the frequency range from 9 GHz to 11 GHz and 16 GHz to 20 GHz respectively. Compared with the conventional band-notch absorber design, the highlight of the proposed structure is that the structure in this paper can achieve two absorption bands and two high-reflection bands just with a single layer. The simple structure makes it more suitable for practical applications, such as combining the proposed band-notch absorber with an antenna or an antenna array to realize low RCS in the absorption bands and work as the ground of antenna in the high-reflection bands.