Design Criteria and Performance Evaluation of TM01 Dielectric Resonators Cavities for Cellular Base Station Filters

This paper suggests to employ DRs operating on TM01, mode in high selectivity, low loss filters for radio mobile base stations (GSM, PCS); the use of TM01 mode instead of TE01, mode (which is more commonly adopted) allows some advantages: lower losses (when tan¿ is not very low), smaller coupling apertures between cavities, larger couplings tunability. The paper describes criteria for dimensioning the TM01 DR cavity, which are based on the evaluation of resonant frequencies, unloaded Q and spurious resonances by means of a mode matching technique; a comparative analysis of the performances obtainable from the two modes (TM01, and TE01,) is also reported. Finally some results obtained from simulations of coupled cavities are shown