Varactor tunable frequency selective absorber

Abstract

A three-layer frequency selective surface (FSS) tunable absorbing filter is presented. Tunability is achieved through the use, in every FSS layer, of commercially available, low-cost, surface-mount, radio-frequency, varactor diodes. The absorber is experimentally tested in a waveguide over the 1.8–2.4 GHz frequency band. It has the potential to form the basis of a smart microwave absorber.