A Quadband Polarization Insensitive and Angularly Steady Frequency Selective Surface for Gain Enlargement of Multiband Antenna

A simply constructed bi-layered compact Frequency Selective Surface (FSS) is reported in this article to attain four distinct stop bands for multiband wireless applications. The compact FSS consists of complimentary oriented repeated cells in top and bottom layers with cell size of 0.135λL×0.135λL and 0.12λL×0.12λL respectively where λL refers the lower band edge wavelength. The FSS exhibits bi-polarized characteristic with angular steadiness till 450 in TE and 300 in TM polarization. The FSS, act as a sub-reflector to broaden the antenna gain, is placed beneath a simple co-planar waveguide (CPW) fed quadband antenna having three triangular patches with rectangular slots stacked together. This united ‘antenna-FSS’ structure attained S11< -10dB spectrums at 3.1–3.7 GHz (17.65%), 5.3–6 GHz (12.34%), 9.7–11.72 GHz (18.86%) and 17.4–19.15 GHz (9.57%) as per experimental evaluation. The ‘antenna-FSS’ offers maximum gain value 9.56 dBi with an enlargement of 4.9 dBi, 3.7 dBi, 4.3 dBi and 5 dBi in its four bands. Adequate radiation efficiency, linear transfer function response and smooth group delay contour are also conquered from ‘antenna-FSS’ in its four bands. The reported ‘antenna-FSS’ is appropriate for multiband wireless technologies as it covers WiMAX, WLAN, ISM, terrestrial and satellite spectrums.