Slow Wave Circuits for Miniature Crossed Field Amplifiers

This paper describes three forms of microwave circuit investigated for application in a miniature crossed field amplifier. All three are suitable for manufacture in the cylindrical geometry required for operation in continuous cathode, re-entrant beam devices, and are intended for forward wave interaction. A strapped vane circuit, developed from the conventional magnetron circuit to provide broadband space harmonic interaction, has been manufactured at X-band and incorporated into operating test amplifiers. A square section helix circuit has been manufactured at X-band for cold test experiments, and an L-band scale model of a ring and bar type structure has been constructed, also for cold test work. Results of dispersion measurements on all three circuit types are presented, and the suitability for crossed field amplifier application discussed.