Optimum design of output cavity in 0.34 THz EIK

The output cavity used in 0.34 THz extended interaction klystron (EIK) is developed and optimized by using theoretical analysis and numerical simulations. Beam-loading conductance is researched by using the small signal theory and the cavity is accordingly optimized to contain eight gaps. Considering of transmission coefficient and feasibility in manufacture, the tapered coupler is presented and the issue of mode competition is discussed. The physical design is simulated and verified by particle-in-cell (PIC) technology finally and the results show that an output power of 143 W can be reached at the frequency of 347.7 GHz, approaching the gain of 37.7 dB.