High-Q tunable dielectric resonator filters

Tunable dielectric resonator filters can potentially address wireless and satellite applications that require very high Q values (4,000 and up) with a limited tuning range (less than 15%). Such high Q requirements cannot be met by any other known non-superconductor tunable filter technology at the present time. The intent of this paper is to provide newcomers and end users with the current status and prospective of using dielectric resonators for tunable filters. It is an enabling technology for high-Q tunable filter applications. A key challenge, however, is to increase the tuning range without degrading the Q value. While several techniques have been reported to demonstrate the feasibility of tuning dielectric resonators, the tunable dielectric resonator filter technology is still in its infancy. Very limited research effort has been dedicated to explore the potential for improving the tuning range. Most of the work reported thus far has focused on the use of TE01deltamodes and standard shape resonators demonstrating a narrow tuning range. We believe that the tuning range can be increased while maintaining reasonably high Q values by exploring the use of other modes and by the use of non-standard-shape dielectric resonators.