A thin wideband circuit analog absorber using square-loop arrays

This paper describes an enhanced thin and wideband circuit analog (CA) absorber consisting of square-loop arrays. The enhanced design replaces the metallic backplate of a circuit analog absorber with a conductor-backed resistor-loaded high impedance surface (HIS). First, a wideband single-layer CA absorber with metallic backplate is designed. The metallic backplate is then replaced by a conductor-backed resistor-loaded HIS to improve the absorption bandwidth. It is shown through simulations that the bandwidth with 10dB reflectivity reduction is 137.6%, while the total thickness of the designed absorber is only 0.078λ_L, where λ_L is the free-space wavelength at the lowest operating frequency.