Characterization of Packaged Dielectric Resonators Coupled to Microstrip Lines

In the last few years, the availability of dielectric materials with high relative permittivity has given a great impulse to the use of dielectric resonators in the microwave frequency range. unfortunately, most of the theories allowing to determine the main characteristics of the resonator -its resonant frequency and its Q factor- omit to consider the electromagnetic fields in the shaded areas (see figure 1) and in the region 1 and 2, all the fields are exponentially decaying [1][2]. So they cannot take into account all the problems related to the packaging of the resonator; yet, it is surely the parameter which determines the accurate design of narrow band filters of highly stabilized oscillators. In these conditions, it seems to be a better practical strategy first, to study the characteristics of the packaged resonator in relation with the considered application and then, to determine the geometry of the coupling microstrip lines related to the box dimensions in the frequency band previously defined. In this paper, we will try to give to the M.I.C. designer theoretical and experimental results allowing to bring such a strategy in operation.