Theory and Experiment of the Wideband Two-Layer Hemispherical Dielectric Resonator Antenna

The two-layer hemispherical dielectric resonator antenna (DRA) excited by an annular slot is investigated. The slot excitation can be placed in the inner or outer dielectric layer, and the two configurations are studied and compared in this paper. Both problems were solved rigorously using the Green's function approach and the method of moments. The maximum impedance bandwidth and a new bandwidth that considers the field pattern are investigated. Good agreement between the calculations, measurements, and HFSS simulations is obtained.