Dual-band nested waveguide antenna employing frequency-selective surfaces

This paper proposes a waveguide antenna that employs frequency-selective surfaces (FSSs). The proposal nests one waveguide inside the other. The top surface of one waveguide acts as the top surface of the other. Waveguide walls are formed by FSSs, which reflect electromagnetic waves at each frequency band. As an example of implementing this proposal, this paper designs a waveguide antenna radiates at 2 GHz and 4 GHz. Electromagnetic field simulation results demonstrate that the fractional bandwidth is 29% (2 GHz) and 16% (4 GHz) for VSWR values under 2.0. The radiation patterns of the proposed dual-band waveguide antenna well match those of the corresponding single-band waveguide antennas, and the peak gain of each frequency band is the same.