Design of selective linear phase cross-coupled dielectric resonator filters

Öztürk, Onur Ozan
In this work, a selective linear phase filter is designed in cross-coupled form using dielectric resonators in Ku band to be used as a channel filter in IMUX of a satellite receiver. Extreme delay flatness is required: 1.5ns delay ripple over 60 % of the passband and symmetric cross-coupled filter with all ideal inverter couplings realizing four finite transmission zeros (FTZ) satisfying also the delay flatness requirements. Design is carried out on the software program FILPRO, then optimized in ADSTM and then on CSTTM. The dielectric resonators used in single mode and operates in the TE01δ mode, which is the fundamental mode of dielectric resonators and has no degenerate modes. The positive inverters (magnetic couplings) are realized as irises while the negative inverters (electric couplings) are realized in ridged waveguide forms which is the main novelty of this thesis. However when the inverters are converted into iris and ridge waveguide forms a tilt is observed in delay exceeding the delay ripple limits. The tilt is then corrected by redesigning the filter by inserting diagonal cross-couplings.