Compact ridged waveguide filters with improved stopband performance

A novel ridged waveguide bandpass filter configuration is proposed. The proposed filter has comparable size to standard E-plane filters while having suppressed spurious resonance. Compactness is achieved by taking advantage of the properties of slow waves in half wavelength resonators, while spurious behaviour suppression is achieved by means of an integrated lowpass structure. Periodicity is readily imposed by cascading ridge waveguides with rectangular waveguides. The structure is simple and compatible with E-plane technology. Numerical and experimental results are presented to validate the argument.