Dual-band resonant cavity antenna with a single dielectric superstrate

We present a novel technique to design a dual-band resonant cavity antenna that has only one dielectric superstrate. The technique is based on using a superstrate slab of high permittivity and a thickness of an integer number of half wavelengths. In representative examples, we use a ray-tracing theoretical model to study the dual-band behavior and explain it by observing how the reflection coefficient of the superstrate varies with frequency. The results are validated by simulation using commercial numerical electromagnetics software.