Equivalent circuit method analysis of the influence of frequency selective surface resistance on the frequency response of metamaterial absorbers

A simple equivalent circuit method has been proposed to provide understanding of the absorption mechanism of a class of metamaterial absorbers. The absorbers are composed of lossy frequency selective surfaces (FSSs) over the grounded dielectric substrates. Based on the analytical method, the influence of FSS surface resistance on the frequency responses of metamaterial absorbers is discussed in detail. It is shown that wideband or narrowband absorbers can be obtained by changing the surface resistance of the FSS. The narrowband absorbers show a similar surface resistance dependence of the absorbing performance to Salisbury absorbers and the maximum bandwidth of metamaterial absorbers can be obtained with the proper surface resistance. This can serve as a guideline for the fast and efficient design of metamaterial absorbers. Finally, experimental results are presented for verifying the validity of the analytical method.