Improvement of traveling-wave tube efficiency through collector potential depression

This paper describes the design of single-stage and double-stage collectors which can be operated at "depressed" potentials. When these single-stage and double-stage collectors were used in conjunction with a traveling-wave amplifier, over-all efficiences of 46 and 57 per cent were obtained, respectively. The maximum increase in efficiency which can be obtained by the use of depressed collectors having one to three electrodes is calculated for various traveling-wave tube design parameters.