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