A novel miniaturized loop based angularly stable and polarization independent multiband bandpass FSS structure for Wi-Max and WLAN applications

In this paper, a novel loop based multiband bandpass frequency selective surface (FSS) structure has been presented. The presented unit cell has been designed using the two square loops and two octagon loops for achieving the multiband characteristics which are extensively utilized in wide range of applications. The sporadic arrangement of these four loops is the key factor to pass the Wi-Max (2.5–2.7 GHz, 3.4–3.6 GHz) and WLAN (center frequency 5.5 GHz) frequency bands. The miniaturized structure gives a wide bandwidth at all the three bands and provides stable resonance for a wider angle of incidence, due to the orientation of loops. The size of unit cell is 0.15 λ × 0.15 λ where λ is the wavelength of first resonant frequency. A 16 × 16 array of the proposed unit cell is fabricated over a FR4 substrate and its simulated and measured results are presented which are in good agreement. The advantage of the proposed FSS structure is its miniaturized configuration showing wider angular stability and polarization independent characteristics.