Recent advances in an EHF helix TWT

This paper presents current efforts at Hughes Aircraft Company, Electron Dynamics Division on an EHF helix TWT. A recently developed tube, the 8900H, has delivered 100 watts of peak RF power and 50 watts of CW power over the frequency range of 30 to 35 GHz. Both the power output and the bandwidth exceeded initial design goals. Excellent beam transmission of greater than 99 percent under depressed collector operation and full RF output power has been consistently achieved on several tubes. In addition, the tube which has a thermally rugged helix supported by beryllium oxide bars has demonstrated significant margin above the power output requirements.