Proposal of over 100-GHz band waveguide switch

A filter bank consisting of switches and band-pass filters is one method for configuring a spectrum analyzer preselector. A long-life switch with high isolation is key to this development. We propose a novel horizontal-moving waveguide switch designed for easy addition of ports compared to commercial rotating switches. The switch has a small gap between the fixed and moving parts with the gap surrounded by chokes. This configuration offers high isolation and long life. It also reduces the size of the filter bank. This paper describes 2 proposed switch prototypes for frequency ranges from 90 to 140 GHz and from 255 to 315 GHz. The measured switch isolation is better than 50 dB and the insertion loss is less than 3 dB for both prototypes.