WR-2.8 Band Micromachined Rectangular Waveguide Filter

A WR-2.8 band bandpass rectangular waveguide filter is designed and microfabricated, in order to satisfy the demand of our WR-2.8 band communication system under development. The filter is a seven-pole waveguide filter. It is designed by classic network synthesis methods and HFSS optimization, and manufactured by microfabrication processes, such as silicon deep reactive ion etching (DRIE) and bonding. An improved microfabrication process is presented, considering the drawbacks of our previous works in D-band and G-band micromachined rectangular waveguide filters. Tests are conducted on a measurement platform constructed by ourselves. The measured minimum insertion loss can be less than 1 dB, the bandwidth is about 20 GHz, and the out-of-band isolation is larger than 30 dB @ 10% relative bandwidth. The measurements demonstrate the feasibility and consistency of the improved process and this process provides an effective way for terahertz waveguide devices fabrication.