Power combiners using whispering gallery dielectric resonators coupled to two parallel microstrip lines

This paper presents a general method to characterize a dielectric resonator coupled to two parallel microstrip lines. The scattering parameters of such a structure are calculated using the finite element method and the coupled transmission lines properties. This method is applied to the case of a dielectric resonator excited on a whispering gallery mode. Thus, the structure is used as a resonant two ways power combiner. In order to optimize the combiner efficiency, the optimum spacings between the resonator and each microstrip line are computed using an equivalent model. Two configurations of the device with different resonators are studied. The results given by the method of characterization are in good agreement with the measurements. A combiner efficiency greater than 82% is obtained at 15.6 GHz