Thin and broadband electromagnetic absorber design using resistors and capacitors loaded frequency selective surface

摘要

A new method using resistors and capacitors loaded frequency selective surface (FSS) to design thin and broadband electromagnetic absorber is proposed. The effect of the loaded lumped elements on the absorptivity of the absorber is investigated through transmissionline equivalent circuit model. The simulations show that this multiple components loaded FSS (CLFSS) absorber has double changeable abilities of adjusting the real and imaginary parts of its input impedance, which leads to improvement of the absorber's impedance matching condition and enhancing of the absorber's absorptivity. Based on the above analysis, two types of CLFSS absorbers were fabricated to confirm the superiority of the multiple components loaded method. One was singly loaded with resistors and the other alternately loaded with resistors and capacitors. Our further measurements show that the alternately loaded FSS absorber has a better absorptivity than only resistors loaded FSS absorber. The alternately loaded FSS absorber with a total thickness of 3.7mm exhibits a broadband reflectivity response with 98.7% bandwidth over the frequency range from 5.9 to 17.4 GHz below -8dB.