Advances in gyro-amplifier research

Summary form only given: Gyro-devices are fast wave devices based on the principles of the electron cyclotron maser^1,2. Gyro-oscillators have been successfully developed in the form of gyrotrons^3,4. Gyro-amplifiers have been studied for approximately as long as gyro-oscillators but in the early years the amplifiers exhibited stability issues. Gyro-amplifiers include broadband gyro-TWTs and the narrower band gyro-klystrons. Introducing distributed losses can prevent gyro-amplifier oscillations, although this approach becomes more difficult at high powers. Garven et al.⁵ successfully demonstrated a `zero-drive stable´ high power gyro-TWT at 35GHz by incorporating lossy ceramic rings. Blank et al.⁶ in 2002 achieved an impressive 100kW peak output power from a 94 GHz gyroklystron.