Abstract
In this paper the realization of multiple additional transmission zeros in folded W-band waveguide filters is discussed. The transmission zeros (TZs) can be placed symmetrically as well as asymmetrically in the near passband region of the filter and arise due to a resonant coupling between source and / or load. Third and fourth order filter set-ups are presented, showing in total between three and six TZs. These zeros can be used to improve the selectivity of the filter without increasing the overall order. The filter design and realization process is discussed. Subsequently, the measurement results are compared with simulation, showing good agreement. As the filters are designed for the W-band, the manufacturing process is connected with some difficulties which are addressed within this paper as well.
Acknowledgements
This work was partially supported by the Spanish Government under Grant TEC2016-76070-C3-1-R (AEI/FEDER, UE)
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