Simulation of a 95 GHz two-stage three-cavity klystron oscillator

A two-stage oscillator consisting of two coupled three cavity klystrons is studied. A small-signal theory of this oscillator is developed, which predicts start-oscillation current and oscillation frequency. Results of 1-D particle-in-cell simulation of the W-band oscillator are presented. The numerical results are in good agreement with the small-signal theory. The simulations predict over 400 W output power with nearly 400 mA beam current.