Development of a 10 MW, 91 GHz gyroklystron

The design uses the second-harmonic mode to reduce the magnetic field requirements and use available TWT drivers. The current circuit design employs five cavities. The input cavity is a fundamental cavity operating with the TE/sub 011/ mode and using radial coupling. The following buncher cavities operate with the TE/sub 021/ mode and are stagger tuned to improve efficiency and bandwidth. The output cavity operates in the TE/sub 021/ mode and has smooth-wall transitions along with a non-linear output taper to minimize mode conversion. A conventional, double anode, magnetron injection gun generates the electron beam. Following the circuit, a large radial gap is introduced in the output waveguide to allow voltage depression of the beam collector to increase the overall efficiency. A hybrid mode is used (TE01/02) to maximize transmission across the gap.