Improved Fully Canonical W-Band Waveguide Filter

In this paper an improved fully canonical waveguide filter which overcomes the major drawback of having a constant attenuation level apart from the passband is presented. By using the principle of resonant hole coupling it becomes possible to assign two additional transmission zeros in the stopband of the filter. These extra transmission zeros are far away from the passband and allow to hold the attenuation level deeper than usually. Measurement results from the improved filter as well as results from a normal fully canonical filter with the same dimensions are presented for comparison.