Performance Analysis of a Single Layer X-band Frequency Selective Surface Based Spatial Filter Implementing Half Jerusalem Cross Slot

Abstract

This work proposes and experimentally evaluates a single layer bandpass frequency selective surface (FSS) that resonates at X-band (8-12 GHz). The metal plate of the unit cell has a half-Jerusalem cross slot of size 0.15λ 0 , where λ 0 is the wavelength corresponding to 10 GHz centre frequency. The effects of unit cell parameters on filter response are analyzed through parametric analysis. The results reveal that the proposed bandpass FSS exhibits good polarization stability and angular stability at oblique angles up to 45 • . Furthermore, negligible frequency deviations in both TE and TM polarizations have also been achieved using this structure. A prototype of the bandpass FSS was fabricated on an FR4 substrate to validate the proposed design which includes 10 × 10 elements in a dimension of 45 mm × 45 mm × 1.6 mm. Measurements show that the bandpass FSS has a fractional bandwidth of 40% centered at 10 GHz from 8 GHz to 12 GHz. The unique feature of the proposed filter is its ability to operate in the whole X band (8-12 GHz) by tuning the filter elements.