W‐band TE102‐mode filter with doubly loaded E‐plane and H‐plane irises

Abstract In this correspondence, high‐precision computer numerical control milling is utilised to demonstrate a doubly loaded iris, cross‐coupled waveguide bandpass filter for inline operation within the W‐band. This sixth‐order filter is designed in a stacked H‐plane configuration and utilises both E‐plane and H‐plane doubly loaded irises to maintain the flow of a TE102‐mode electromagnetic field. In this configuration, a high rejection level is maintained outside of the passband while a good unloaded quality factor is obtained through the support of larger resonator dimensions. The filter is designed for approximately 2% fractional bandwidth centred at 97.5 GHz and has been fabricated as three brass components. Measurements of the filter agree very well with the simulated results and demonstrate a spurious‐free design over the full W‐band