Study of terahertz extended interaction oscillator

A terahertz extended interaction oscillator (EIO) operating at 0.225 THz is studied in this paper. A rectangular reentrant coupled-cavity is proposed as the slow-wave structure (SWS) of the EIO. Due to the complexity of the structure, the equivalent circuit method (ECM) is adopted to calculate the dispersion relation of the cavity mode. Circuit parameters of the cavity and the coupling slot are studied in detail and a feasible calculation method is proposed in this paper. Meanwhile, the theoretical study is compared with the simulation study by a t simulation software CST and particle in cell (PIC) code. By comparison, the theoretical result agrees well with the simulation result for a certain dimension of the period 0.3mm, gap length 0.1 mm, cavity height 1.6 mm and width 0.76 mm. By PIC code, a 14-gap EIO is simulated, the operation mode is close to the point where betaL =2pi with the beam voltage 13 kV and current 105 mA. The simulation results show that the generating frequency is 0.225 THz and the output peak power is 44 W.