Multilayered Bi-Directional Dual Band Frequency Selective Surface Design

The dissertation presented here designs a dual band (band-pass) frequency selective surface (FSS) that passes microwave frequencies of 8.5 GHz and 14 GHz. It is a bi-directional FSS that works the same from both the sides. It is a multi-layer FSS where a circular slot is sandwiched between two circular patches. Two layers of substrate are used (Rogers Ultralam 1250) with εr=2.5. Outer sides of these substrates contain circular patches of copper and inner side contain copper plane with a slot of same size as the circular patches. This works only designs one unit cell and analyzes its behavior. For more than four decades, FSSs have attracted much attention because of their comprehensive applications, such as polarisers, filters, sub-reflectors, and band-pass hybrid radomes. In some applications, multiband FSSs are needed for the design of dual-reflector antennas. Frequency selective surface find their application as band pass and band stop filter over other electromagnetic structures. Simulation is done on EM-CAD tool HFSS 11.1.