Design of Polarization-Insensitive Near Unity Dual Band Microwave Absorber for EMI/EMC Applications

Abstract

This paper introduces the novel miniaturized dual band microwave absorber. The structure is composed of two independently connected microstrip lines which resonate to produce two transmission nulls that have nearly unity absorption peaks. The structure is designed on a substrate which is ideal for generating required transmission nulls. The proposed structure has absorption peaks at the X band frequencies of 10.68 GHz and 11.33 GHz frequencies which are used in the Earth Exploration Satellite Service (EESS) and GSS FSO systems respectively. The results demonstrated that such an absorber does have good absorption and is polarization-independent about large incident angles for both TE mode and TM mode in the two absorption bands. Simulated results demonstrate that the absorption peaks at normal incidence under various polarization angles gives nearly unity absorption. The absorption rates, reflection characteristics and surface current distributions are demonstrated to perfectly illustrate the mechanism of the proposed microwave absorber. The suggested microwave absorber provides better shielding for electromagnetic waves which will be useful for reducing the EMI effects.