A Noise Rejection Filter for Waveguide Carrying High Power

A novel design for a waveguide band-rejection filter carrying high power in its pass band is presented. The resonant cavities of the filter are mounted in pairs on the narrow walls of the guide and coupled to the guide through rectangular openings the full height of the guide. Thus there are no edges or radii on which electric field concentrations can occur. An X-band model having six cavity pairs had a rejection greater than 80 db over k^> Mcps in its 6top band with an insertion loss under 0.05 db and VSWR under 1.02 in its pass band. With water cooling, the filter carried over 300 lew CW without breakdown. Accepted for the Air Force Stanley J. Wisniewslci Lt Colonel, USAF Chief, Lincoln Laboratory Office