Design of band-pass Filters at Ka-band with waveguide- to microstrip- transition

A rectangular waveguide e-plane fin-line filters compared with metal insert filters at Ka-band is introduced. Optimized design dates for four- to five-resonator type filters are given for mid-band frequency of about 35.6 GHz. Emulational passband insertion losses of prototypes are 0.02dB and 0.5dB respectively. A type of waveguide- to microstrip- transition on a single dielectric substrate for millimeter wave band-pass filters is proposed. The insertion losses of the two filters connected with transition are 0.5dB and 0.9dB respectively, which satisfy engineering.