Tunable Filters Based on Dielectric Resonators

Abstract

Summary form only given. The 'TUF' tuneable filters Framework 5 project was focused on the development and characterization of tuneable ceramic dielectric resonators, of tuneable filters based upon them and on cryogenic bolometry based on a coupled tuned resonator. Its objectives were conceived in the light of strategic developmental needs of the European Community. Contractors of the project were as follows: National Physical Laboratory (NPL), Ericsson Radio Access, Filtronics Comtek (FC), Josef Stefan Institute (JSI), Forshungszentrum Julich (FZJ), London South Bank University (LSBU), and Warsaw University of Technology (WUT). Several prototype resonators and tuned filters have been constructed by TUF partners based, respectively, on ferromagnetic, simulated-MEMs and piezoelectric tuning. The resonators and filters include the following: ldr Single-pole ferromagnetic axially tuned filter (WUT ) ldr Single-pole ferromagnetic circumferentially tuned filter (WUT) ldr Two-pole ferromagnetic axially tuned filter (WUT) ldr Two-pole ferromagnetic circumferentially tuned filter (WUT) ldr Single pole MEMs-tuned filter with 4 tuning slots (FZJ) ldr Single-pole dielectric resonator filter with piezoelectric bimorph tuning (LSBU) ldr Two-pole hybrid-mode dielectric resonator filter with piezoelectric bimorph tuning (LSBU) ldr Four-pole hybrid-mode filter based on two dielectric resonators with piezoelectric bimorph tuning (LSBU) .All of these devices present significant steps forward in filter design and have provided important new practical information about the implementation of electronic tuning in high Q-factor filters. The three filters, in bold type in the above list, each employing a different tuning mechanism, and each developed in a different TUF partner's laboratory, are the most advanced filters of each type that were comprehensively tested during the TUF project.