Dielectric-loaded interaction structure for gyrotron-travelling wave tube

The distributed dielectric loading technology has been successively applied in many gyrotron-travelling wave tube(gyro-TWT) experiments to suppress absolute instabilities. Based on the stability analysis of a Ka-band TE01-mode gyro-TWT with distributed-loss interaction circuit, propagation loss of operation and parasitic modes, start current of operation mode under different propagation losses are calculated. Start lengths of the three main parasitic modes under different loss-loading conditions and operation currents are given. Dielectric loss parameters including thickness of loss layer and relative permittivity are then decided. Taking advantage of the optimized parameters of loaded dielectric, a high gain scheme has been demonstrated in a 34 GHz, TE01-mode gyro-TWT, producing 160 kW sa