Tunable Absorptive Frequency-Selective Transmission Structure

A tunable absorptive frequency-selective transmission structure (AFST) is proposed in this paper. It is constructed from an ultra-wideband absorber integrated with transmission path to provide the transmission window. The losses in the passband is bypassed utilizing series resonator in shunt with the source of losses. By tuning the series resonator concurrent with the passband, a tunable AFST structure with low insertion-loss is accomplished. One design is simulated using CST Microwave Studio, which exhibits a tuning range from 3.6 GHz to 4.3 GHz with two sided and wide absorption bands. This tunable AFST structure works for single polarization, which represents the main limitation of the proposed structure.