Stop-band improvement of rectangular waveguide filters using different width resonators: selection of resonator widths

Rectangular waveguide resonators having different widths can be mixed in order to improve the stopband performance of band-pass filters. Two effective procedures for the choice of the resonator widths are presented and implemented to realise X-band 6-cavity filters which hold 30 dB of attenuation over a frequency range 40% wider than a standard filter. Theoretical and experimental results are shown and commented on.