A novel W-band waveguide bandpass filter based on nonresonating nodes

In this paper a low-loss pseudo-elliptical four-pole filter at 92.7GHz with two transmission zeros is presented in order to fulfill stringent specifications. Compared with traditional cross coupling filters, the proposed pseudo-elliptical filter can be manufactured more conveniently due to the introduced non-resonating nodes. What's more, relatively simple structures to implement extracted poles have been proposed. Finally, the effect of fabrication process using high speed CNC milling machines is also discussed. The simulated result shows that the structure is insensitive to the fabrication tolerance and the insertion loss from 91.5GHz to 94GHz is less than 0.4dB, and the out of band rejection is more than 40dB at 89.2GHz and 96GHz.