High Power Millimeter Wave Amplifier

This final report describes Phase II of a program to develop a high power 94GHz amplifier based on the Gyrotron or cyclotron resonance interaction. Ultimate goals are 100 kW peak power, 10 kW average power, at lease 4 bandwidth, 30 efficiency and 40 DB power gain. The experimental work in Phase II was performed at C-band 5.0GHz to demonstrate feasibility of this approach. Following a brief review of the program as presented in the first section, the final testing of the 3-cavity Gyroklystron developed in Phase I is described in section 2 of this report. In section 3, a complete description including test results of the 5 GHz Gyro-TWT is given. Operating the Gyro-TWT at 60 kV beam voltage at 5 amperes beam current yielded 50 kW output power with 18 dB saturated gain 24 dB small signal gain at 6 bandwidth and 16.6 efficiency. Small signal gain and beam mode-RF mode dispersion curves are presented in section 4. A ratio of perpendicular to parallel momentum of 1.5 yielded excellent agreement between the theoretical and experimental results.