Improved coaxial low-impedance transit-time oscillator loaded with washer-like structure

An improved low-impedance transit-time oscillator loaded with washer-like structure is proposed and investigated by using the 2.5D fully electromagnetic particle-in-cell code. The extractor operates at -like mode, which is advantageous to keep a high efficiency of the beam-wave interaction. Due to the adoption of the tapered output waveguide, the microwave can be extracted more effectively. Loading inductive metal rods can not only support the washers, but also ground the DC induced charge in the washers. The optimized simulation results show that a 7.76 GHz, 2.74 GW microwave can be obtained with a efficiency of 40% under the condition of the diode voltage 530 kV，the current 12.9 kA and the guiding magnetic field 0.7 T.