Novel invasive electronic tuning of dielectric resonators

Electronically tuned dielectric resonator (DR) structures have, in the main, in the past employed external tuning techniques. This paper presents the investigation results on a novel tuning technique termed "invasive tuning". Invasive tuning involves the machining of rectangular shaped slot in the dielectric resonator and embedding the tuning mechanism inside this slot, which is within the boundary of the resonator. This results in a very compact tuning arrangement, which provides substantial tuning bandwidth of 7.1% using electronic means. The effect of slot perturbations on the DR resonant frequency and quality-factor are reported in this paper. Variations in the performance of the slotted resonator are characterized and the results from a number of tuning experiments are discussed. The incorporation of the new tuning technique into practical circuits such as filters have shown good performance for a compact design. This technique may also be used for the electronic timing of oscillators.