High-Power Ka-Band Bandpass Filter based on Movable Dielectric-Loaded TE01δmode Resonators

The design and first experimental results of a Ka-band bandpass filter for high-power satellite applications are presented in this paper. The filter is based on dielectric-loaded TE01δ mode cylindrical cavity resonators, which allow for minimizing the volume occupation with respect to other standard technologies (i.e. circular cavity filters) still maintaining high unloaded Q-factors (>7000). The proposed ceramic resonator can be moved along its axis inside the resonant cavity. The reconfigurable position of dielectric load allows the regulation of the resonant frequency without additional tuning mechanisms, which can degrade the unloaded Q-factor of the resonator and affect the power-handling capabilities. The materials and geometries have been accurately selected for improving also the high-power performance of the filter in terms of thermal-flow and multipactor up to 150 W continuous wave of the input RF power. The feasibility of the proposed approach has been experimentally demonstrated by the RF measurements of a 6th order filter prototype.