Thin wideband absorber with optimal thickness

The known methods for designing nonmagnetic absorbers usually aim for either the reduction of total thickness or increase of absorption bandwidth by sacrificing the other parameter. The conventional circuit analog absorbers aim for large bandwidths whereas the newly proposed meta-material or optimized geometry designs try to reduce the thickness of the absorber. By the aid of the capacitive circuit absorber approach, an optimal method for designing thin absorbers with practical bandwidths is proposed. An absorber is designed for the whole radar X-band with total thickness about λ/10. It is shown that the absorber thickness is satisfactorily close to the theoretical limit. The effect of mutual coupling on the performance of thin absorbers are investigated and some techniques for reducing the mutual couplings are suggested.