Polarization-Insensitive Absorptive/Transmissive Reconfigurable Frequency Selective Surface With Embedded Biasing
Patinavalasa Megh Sainadh, Aditi Sharma, Saptarshi Ghosh
Abstract
In this letter, a polarization-insensitive absorptive/transmissive reconfigurable frequency selective surface (RFSS) using p-i-n diodes is presented. The RFSS structure incorporates two periodically arranged metallic patterns on both sides of an FR4 dielectric substrate, where the p-i-n diodes are aligned symmetrically on the bottom surface. Depending upon the diode biasing conditions, the geometry behaves as a radar absorber and a bandpass filter under different working states. The simulated response exhibits a near-unity absorption response (having absorptivity of 93.51%) at 6.93 GHz during <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> state of the diode, whereas the incident electromagnetic wave gets transmitted through the structure at 5.62 GHz during <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> state. An embedded biasing circuitry has also been developed comprising metallic vias and inductors, such that the geometry displays polarization-insensitive and angularly stable responses for both states. The structure has been analyzed with the help of circuit modeling and other parametric variations to explain the switching methodology. A prototype has been fabricated and measured using the parallel-plate waveguide technique, which results in a good agreement with the simulated responses. Such RFSSs can be marked as a potential element for various radome applications.