RF loss as a design parameter in traveling wave tubes

In a traveling wave tube (TWT) loss is usually in the form of an attenuator, or sever, which is designed to absorb the RF power on the circuit but allow the RF power in the beam. This paper discusses additional uses of RF loss to enhance the performance of TWT's. The additional uses include the following: prevention of backward wave oscillation (BWO) in helix derived circuits, suppression of band edge oscillation (BEO) in space harmonic circuits, enhancement of overdrive power conditions in TWTs, reduction in AM-PM distortion and harmonic power in overdrive region and efficiency enhancement for medium gain (i.e., 15 to 20 db) TWT's.