Low profile filter using open disk dual mode dielectric resonators for microcellular base station

This paper present a low profile bandpass filter using open disk dual mode dielectric resonators for microcellular base stations. The resonator consists of two dielectric disks in a cylindrical cavity, and the torus electrode increases the unloaded Q of the resonator. An equivalent circuit consisting of ring shaped transmission line with electrical length of 2¿ represents the dual mode resonator. A multi-pole bandpass filter can be designed by the Chebysheff type deign method. A 6-pole bandpass filter with the center frequency of 947.5 MHz and insertion loss of 0.7dB is fabricated. Measured response of the filter agrees with the simulated one. The dimensions of the filter are 158×54×23.5 mm.