Bandpass and band-rejection filters with electrically controlled dielectric resonators

Functional possibilities of UHF and microwave devices based on dielectric resonators (DRs) could be essentially extended if the basic resonant frequency of the attenuation-frequency characteristic (AFC) could be fast controlled. It was shown that each DR by itself allows to control its resonant frequency up to 10-30% with a high Q-factor preservation (Poplavko et al., 1995). However, the commonly accepted constructions of DR-filters are unsuitable for such controlling owing to the unwanted change in their AFC. Proposed in this paper is a new design of DR-systems which provides AFC shift in frequency with the shape of the AFC being undistorted due to the independence of the modes of DRs employed. Based on these concepts, various band-pass and band-rejection overturned DR-based filters are realized. Some new results were obtained as to filter AFC control.