Balanced/balun filters based on dielectric resonators

Dielectric resonator (DR) owns advantages of high quality factor, high power capacity, superior temperature stability, moderate circuit size, etc., emerging as a promising candidate for future small base station systems. According to the field distribution of the DR's fundamental mode, proper excitation schemes are established to differentially feed the DR so that it can be applied in designing balanced/Balun filters. The most used DRs in microwave filter designs are rectangular and circular ones, as well as their derivations. This paper gives a review of the recent works on balanced/Balun filters based on the various types of dielectric resonators (DRs), which have been pursued by the authors' research group.