Design of a high gain open waveguide antenna combined with an active frequency selective surface

In this paper, we present a reconfigurable band pass filter (BPF) design based on a periodic frequency selective surface (FSS) structure. Using varactors, which are included in the unit cell of the FSS, we may change the frequency response of the FSS, as shifting the center frequency and changing the Q factor. Using such approach, it is also possible to design FSS with a miniaturized unit cell. The proposed FSS may operate as a superstrate, and increase the gain of an aperture antenna.