60MHz DR Filter for both PCS and UMTS in the same Housing

The new tunable filter technology is used here to build full band (60 MHz) 9 pole dielectric resonator (DR) filters tuned at two different ranges separated by 200 MHz, PCS band (1930-1990 MHz) and UMTS band (2110-2170 MHz). All the measurements are taken in the same housing and the same resonators. The double conical resonators when put in proximity, provide the required strong couplings for the full band filter. The gap between the two conical parts that make the resonator, regulates the frequency over a very wide range without affecting the quality factor and helps provide a safe spurious free band. The fine tuning of the frequency is achieved with metal tuning plugs. Two different dielectric constants are used epsiv_r=35 and epsiv_r=45. In both cases, a typical 0.4 dB insertion loss is achievable for the 9 pole filter. An optimization of the design can push it very well near 0.3 dB for Er=35 or even lower. The design is patent pending and to our knowledge this full band DR filter tuned over such a wide range is presented for the first time.