Inkjet-printed broadband FSS-based absorber with improved absorption characteristics

Abstract

Abstract We present the design for a thin planar microwave absorber depicting near unity absorption over a wide bandwidth. The absorber consists of a single layer of resistive frequency selective surface inkjet printed over a paper substrate and suspended over a grounded foam. We have been able to achieve 99.99% absorption of normally incident radiations from 9.7 to 11.74 GHz at an extremely low level of −40 dB absorption bandwidth. The proposed absorber is thin (0.22λ0 at the center frequency), polarization-insensitive, and presents −10, −20, −30, and −40 dB fractional bandwidths as 89.83%, 55.41%, 33.30%, and 19.03%, respectively. It is worth mentioning that the design of an absorber with such steep slopes is highly stringent and requires special attention. Finally, we have experimentally demonstrated the perfect broadband absorption characteristics with a fabricated prototype.