Slow wave structure in cross-field backward wave terahertz oscillator

As one kind of terahertz sources, the cross-field backward wave oscillator requires a slow-wave structure (SWS) to transmit electromagnetic waves which is difficult to fabricate. This paper describes the performance of the open rectangular grating wave guide SWS in terahertz and the design of SWSs. By using field-matching method, the dispersion equation and the average coupling impendence expression are obtained and solved. And the length of the period of SWSs is considered to be important because the coupling impedance can be optimized by simply changing it without other adverse effects. The process and results of design of SWSs are summarized and verified by a simulation using PIC method and all the results included different structures with distances between two comb teeth ranging from 0.01 to 0.025 mm，and the frequencies ranging from 300 to 420 GHz.