Transmission-Band-Switchable Absorptive/ Transmissive Frequency Selective Surface Using Liquid Metal

Abstract

A transmission-band-switchable absorptive/transmissive frequency selective surface (ATFSS) based on liquid metal is proposed herein. The ATFSS realizes <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> -band absorption, and the transmissive Ku-band can be turned <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> or <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> using loaded or unloaded liquid metal and by changing the spacing between the lossy layer and the transmission layer. The simulation shows that the ATFSS maintains an absorption rate of >80% at 3.1–8.9 GHz; when the transmission band is opened, the | <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> | < 3 dB band is 10.7–17.22 GHz. When the transmission band is closed, all the electromagnetic waves at the Ku-band are reflected. An ATFSS prototype was fabricated, and the measurement results effectively validated the above design. Moreover, the ATFSS could be used in high-temperature environments owing to the good thermal conductivity of liquid metal.