Novel angular-independent higher order band-stop frequency selective surface for X-band applications

A higher order miniaturised band-stop frequency selective surface (FSS) with angular stability performance for X-band applications is presented in this study. The miniaturisation has been achieved by incurving the arms of conventional cross dipole shape inside. The unit cell size of FSS is diminished up to 75% compared to cross dipole FSS operating at the same resonant frequencies. Moreover, the presented FSS is designed to exhibit stable angular performance for incident angles up to about 60 degrees for TE- and TM-polarised waves. The maximum relative frequency deviation is 1.28% with respect to different angles of incidence. Although the designed FSS consists of two layers, higher order and sharp roll-off filter characteristics have been obtained. The simulation of the proposed FSS is performed with the CST MWS. To verify the simulation results, the presented FSS is measured and a good match between the experimental and simulation results are obtained.