A Novel Dielectric-Loaded Dual-Mode Cavity for Cellular Base Station Applications

A new class of dual mode dielectric resonator filter for mobile communication systems is presented. The proposed resonator exhibits high unloaded quality factor and reasonably wide spurious operating window. Based on this cavity, a 4-pole dual-mode Generalised Chebyshev filter is developed and fabricated in the stacked configuration. An unexpected spurious mode is appeared at 2.3 GHz due to improper coupling. A coupling technique for eliminating the unexpected spurious resonance is proposed. The obtained experimental and measured results with an asymmetric transmission zeros confirm the validity of the proposed resonator for releasing filters for cellular-radio base stations.