A fast-space-charge-wave electron beam duplexer

This paper will describe a device capable of interacting with the fast space charge wave of an electron beam, utilizing a conventional helix. Complete energy interchange occurs for two coupled positive energy modes if the propagation characteristics of the two waves are identical over the band and the Kompfner dip length is independent of frequency. In this device the Kompfner dip condition is satisfied for operation over an octave bandwidth. Experimental evidence of this type of operation has been obtained on both C and S-band versions. The device has a number of interesting applications. One of these, a duplexer, has been designed to operate at 10 kw peak power, 200 watts of average power, and protects the receiver against signal power greater than 10 mw. The operating characteristics of this device will be described.