Theoretical Optimization and Validation of a Wideband Gyro-TWT With Curved-Profile Circuit

The large-signal theory for curved-profile circuit and magnetic field of gyro-TWT is presented. According to it, an optimization method is proposed to achieve effective wave-particle interaction over a wide frequency band through a curved-profile circuit with cutoff sections and gyrotron solenoid magnetic field. It avoids strict limit of grazing magnetic field along the circuit position to improve the design freedom. On this basis, a Ka-band gyro-TWT operating at TE01 mode is theoretically designed and well validated by particle-in-cell (PIC) codes and hot-test experiments. The developed amplifier achieves an output power of above 134 kW range from 27.7 to 31.7 GHz, with an interaction efficiency of above 22.3% over the entire band.