Low noise, low phase distortion 120 W K-band TWT

Summary form only given. Boeing Electron Dynamic Devices (EDD) has continued the development of a special class of low phase distortion TWTs optimized for digital communications in the 18-21 GHz frequency band. The first of these devices, the model 995H, featured extremely low AM/PM conversion of only 2/spl deg//dB. This paper reports the development of a new version, the model 995HA, wherein we have reduced the noise power of the device while continuing to maintain the low phase distortion. The 995HA has a basic electronic efficiency of 18%. Using a multi-stage depressed collector, the TWT has an overall efficiency at saturation of approximately 55%. These low efficiencies are a result of the circuit design trade-offs needed to produce the low phase distortion characteristics.