Dielectric combline resonators and filters

The dielectric combline resonator combines the merits of the metallic combline and dielectric loaded resonator. By replacing the inner conductor of the conventional combline resonator by a high E, dielectric rod, higher unloaded Q can be expected. Resonant frequency, unloaded Q, and coupling coefficient of the resonator are obtained by a rigorous mode-matching method. An eight-pole elliptic-function dielectric combline resonator filter was designed and tested. Measured frequency responses verify the theory.