Simple computation of the coupling coefficient for loop-coupled resonant cavities

A simple procedure is described to compute the coupling coefficient of a resonant cavity that contains a dielectric resonator. The resonant frequency and the unloaded Q are computed from the modal solution without the presence of the loop. An equivalent circuit is obtained for the unloaded cavity, and the loop coupling is represented by a series inductance that is determined by a low-frequency approximation. The procedure enables computation of the resonant frequency, unloaded a and the coupling coefficient for a dielectric resonator in a cylindrical cavity. The measured input impedance of the parallel-plate resonator is in good agreement with computed values. (C) 2000 John Wiley & Sons, Inc.