MIC Directional Filters Using Dielectric Resonators

Three novel, simple realizations of Microwave Integrated Circuit (MIC) directional filters using cylindrical dielectric resonators are described. These are a filter employing two three-port circulators for separation of the band-pass (B-P) and band-rejection (B-R) ports, a traveling wave filter employing two 3-dB hybrids separating the B-P and B-R ports, and a filter consisting of two rnicrostrip lines with a dielectric resonator (d.r.) suspended between them. Approximate methods of calculating the filters resonant frequency and the coupling of the dielectric resonator to the microstripline are also given.