Development of Ka-band space and high power helix TWTs at IECAS

Development of Ka-band TWTs at Institute of Electronics, Chinese Academy of Sciences (IECAS) are reported, include 50W space TWT and 200W high power helix TWT. The space TWT has 50% efficiency, good linearity, while TWTA (TWT+EPC) has 45% efficiency. The high power prototype TWTs have 250W CW output power with 2GHz bandwidth, 150W output power over 30-40GHz.