Simulation of Beam Wave Interaction for a helix space TWT's

The RF performance of a medium power space TWT is decided by the design of the helix slow wave structure. The helix slow wave structure should allow propagation of the RF wave with desired phase velocity, minimum RF loss and maximum possible RF field across the electron beam. The helix SWS is the main deciding factor of the RF performance of a TWT, e.g., output power, gain, efficiency, operating bandwidth, and linearity. In this paper RF section for Ku band (10.7 to 11.8 GHz) 140 W helix traveling wave tube has been proposed for the Increasing demand in the satellite communication system. For the design of helix SWS, software codes: SUNRAY-1D &SUNRAY-3D, CST-MWS have been used. SWS have been designed for electron beam at beam voltage 5.9 kV and beam current 100 MA with beam fill factor 0.5. For SWS power (>42W) and electronic efficiency (> 19.7) is achievedfor Linear Helix Space TWT, phase shift (15.516 to 55.778) and Gain (20.828 to 22.584 dB)