Design and optimization of complementary frequency selective surface using equivalent circuit model for wideband EMI shielding

The electromagnetic interference (EMI) caused by microwave sources leads to the malfunction and faulty readings of many real-time systems. Hence it is essential to provide EMI shielding for sensitive electronic devices and chambers. An array of periodic elements offers advantages such as transparency and opacity at selected frequencies with a lower weight. In this regard, two closely coupled periodic complementary conducting elements; popularly known as complementary frequency selective surfaces (CFSS) has been analysed for wideband EMI shielding application. A simple equivalent circuit (EC) in conjunction with the transmission line (TL) model is used to analyse the response of the presented element. Further, an extensive parametric study of CFSS aimed at their EC model optimization is presented. The CFSS exhibits a highly stable response with two controllable passbands for normal and oblique incidences. The validity of the proposed method is verified with the full-wave simulations and measured results of the fabricated prototype in a free space measurement setup.