A novel compact polarization independent triple band reject frequency selective surface for the security of wireless communication

A periodic frequency selective surface (FSS) having triple frequency band reject behaviour has been proposed with a square and two dodecagon shaped element. These three elements of the FSS unit cell are embedded on the FR-4 substrate, which acts as a triple band reject filter on the frequency band 1.8 GHz, 2.5 GHz and 5.5GHz to avoid the leakage of GSM, WiMax and WLAN signal outside the building. The FR-4 substrate has the loss tangent of 0.02 and relative permittivity of 4.4 with the dimension of 0.12 λ × 0.12 λ that told us the compactness of the structure. The designed FSS has verified by its simulated results and realized in CST Microwave studio in frequency domain solver based on FDTD method as well as also verified in the ANSYS HFSS software. The proposed FSS exhibits more than 91% band reject characteristics for the frequency band 1.8 GHz, 2.5 GHz and 5.5GHz. The FSS unit-cell has symmetrical structure to allow the stable behaviour for both TE and TM mode with the variation of incident angles from 0°–60°. Moreover, the stable resonant frequency response and polarization independence has verified by all its simulated results.