On the probe-fed dielectric resonator inside the parallel-plate waveguide

In this paper, the probe-fed dielectric resonator (DR) placed inside the parallel-plate waveguide is studied theoretically and experimentally. Simple formulas for predicting the trapped- and leaky-mode resonant frequencies are presented. The cylindrical-harmonics expansion method is used to find the input impedance of the configuration. The effects of the probe length, dielectric constant, and DR radius/height ratio on the input impedance are discussed. It is found that the probe can substantially change the characteristics of a mode when it exceeds a certain length.