Switchable Rasorber/Absorber with Frequency Tuning Capability

A multifunctional frequency selective rasorber (MF-FSR) with mode switching and frequency tuning capability is introduced in this paper. It consists of an absorbing layer and a bandpass frequency selective surface (BPFSS) layer, separated by an air-spacer in the middle of them. It can be switched to the rasorber mode or absorber mode by turning the PIN diodes ON or OFF. When in the absorber mode, it functions as a wideband absorber with its absorption more than 80% from 0.95 to 3.5 GHz. While switched to the rasorber mode, it achieves a passband with a low insertion loss between two neighboring absorption bands. Through applying different bias voltage to the embedded varactor, the transmission band can be tuned from 1.1 to 1.7 GHz. Equivalent circuit model (ECM) method is adopt to analyze the operating principle of the MF-FSR.