Analysis of a dielectric resonator antenna in a cylindrical conducting cavity: HEM modes

Numerical modelling has been performed for the hybrid HEM modes of a flush-mounted dielectric resonator antenna in a cylindrical conducting cavity. The antenna is formed by a conducting cavity with a dielectric post and radiates through an annular slot in the upper ground plane. Coupled aperture magnetic current integral equations are used to model the slot and the effect of the post resonator and the cavity are included via Green´s function techniques. The moment method is applied to the coupled integral equations and the complex resonant frequencies for the antenna structure are found by searching for the zeros of the determinant of the impedance matrix in the complex frequency plane. The radiation Q factor, slot field distribution and radiation field are subsequently computed at the resonant frequency. The HEM modes with the lowest resonant frequencies have been investigated for different geometrical configurations