Theory and experiment of the cavity-backed slot-excited dielectric resonator antenna

A slot-excited hemispherical dielectric resonator antenna backed by a rectangular cavity is studied theoretically and experimentally. The magnetic-type dyadic Green´s function for the rectangular cavity is derived using the mode-matching method. An integral equation for the equivalent magnetic current is obtained by enforcing the boundary condition across the slot. The moment method with the Galerkin´s procedure is then used to find the magnetic current in the slot and, hence, the input impedance of the antenna. Measurements were carried out to verify the theory and good agreement is obtained. The effects of the slot inclination angle, of the slot offset, and of the cavity size on the input impedance are discussed