Polarization Insensitive Broadband Switchable Frequency Selective Rasorber/ Absorber

Abstract

In this paper, a polarization insensitive rasorber geometry with switchable transmission/ reflection characteristic is presented. The proposed structure consists of two layers separated by an air spacer; the top lossy layer is achieved using a cross dipole geometry made of resistive ink and the bottom layer is a slot-based topology with four embedded p-i-n diodes. The use of p-i-n diodes help in switching the working state from transmission band to reflection band as the diodes' bias condition changes from OFF to ON state. Thus, the overall geometry exhibits a rasorber response (absorber + transmitter) during OFF state,whereas a wideband absorber is attained during ON state. The absorption response is found from 7.5 to 14 GHz under both the states, whereas the transmission band is observed at 2.82 GHz under OFF state. A prototype of the structure has been fabricated and the measured results confirm the proposed switchable concept, exploiting the p-i-n diodes.