An Angularly Stable and Polarization Insensitive Miniaturized Frequency Surface for WiMAX Applications

This paper presents a miniaturized, polarization insensitive and angularly stable frequency selective surface (FSS) for WiMAX (3.5 GHz) applications. The proposed FSS structure improves upon conventional curved units by incorporating 45∘ tilted dipoles with extended lengths to increase the effective electrical size. The proposed FSS is printed on float glass with a dielectric constant of 8. The unit cell dimensions are 0.062λ0×0.062λ0 (where λ0 is the free space wavelength at the first resonant frequency). It exhibits a bandstop characteristic at 3.5 GHz with a bandwidth of 540 MHz (-10 dB). This FSS demonstrates a stable frequency response under incident angles ranging from 0∘ to 80∘ for both horizontal and polarization angles. Furthermore, the proposed structure is further analyzed through the derivation of an equivalent circuit model. Finally, a prototype of adequate size is fabricated to validate the simulation results. Both the simulation and measured results confirm the stable performance of the proposed FSS.