Multilayer FSS Designed with Wide Band-Notching Characteristics for Electromagnetic Shielding for X Band Applications

In this paper, a frequency selective surface (FSS) based out-of-band absorber and in-band reflection for gain enhancement in X-band application is discussed. This work focuses on reducing interference and noises that may distort the communication that functions at X -band, such as RADAR applications for target detection, Satellite communication, Air traffic control, etc. The proposed design consists of three different layers where the top layer behaves as a passband outside the working frequency and the middle layer behaves as a stopband, which is responsible for the notching of in-band and the bottom layer consists of a metallic copper plane responsible for stopping signal transmission. Both the top layer and middle layer are designed on an identical FR-4 substrate having dielectric constant of 4.3 and thickness of 1.6 mm. The metallic structure on the substrates is annealed copper with a thickness of 0.035 mm. The proposed work achieves out-of-band absorption at 6 GHz and 14.5 GHz with 99 % and 99.2 % absorptivity, respectively and wide notched-band from 7 GHz to 13 GHz with a peak level of -3.34 dB reflection.