A Compact Frequency Selective Surface based X band Spatial Bandpass Filter Realization

A compact single layered frequency selective surface (FSS) based bandstop filter for X band applications is proposed. The filter is implemented using 4×4 array of unit cells (8×8 mm2) consisting of a patch inside the square loop. The dimension of the unit cell is determined by equivalent circuit model and optimized to achieve desired performance. The overall dimension of the proposed filter is 36×36×1.6 mm3 designed on FR4 substrate with loss tangent 0.02. The transmission and reflection behavior of the filter is analyzed by varying the square loop size, gap between the square loop resonator and the patch size. The simulation result reveals that the filter resonates at 9.6 GHz with a bandwidth of 1.2 GHz. The performance of the proposed filter is illustrated for different angle of incident and results are also presented.