Switchable Optically Transparent Frequency Selective Surface for ultrawide-band Electromagnetic Shielding

Abstract

An optically transparent frequency selective surface (FSS) for broadband electromagnetic shielding is proposed in this paper. The proposed FSS consists of a polymethyl methacrylate (PMMA) layer sandwiched between two Polydimethylsiloxane (PDMS) layers. The Ω-shape pattern is engraved on PDMS to form the microfluidic channels, where a liquid metal flows through. The electromagnetic response of the proposed design can be switched from all-pass to bandstop characteristic by injecting a liquid metal such as eutectic gallium indium (EGaIn) into the microchannels. Simulated results demonstrate that the 18.8 GHz bandwidth of SE ≥ 10 dB is achieved, with angular stability up to 80° for both TE and TM modes. Meanwhile, the transparency of the proposed shield can reach up to 81%.