为解决正交场返波管太赫兹源慢波结构的设计问题，研究了开放式单排矩形梳齿慢波结构的色散及耦合阻抗特性并给出了设计思路及结果。利用单模近似法和数值计算得到了各几何参数对慢波结构性能的影响。结果表明：慢波周期长度可相对独立地优化耦合阻抗；设计慢波结构时可根据工作频率、加工工艺和电子枪性能确定其余三个几何参数，主要是对慢波周期长度进行调节。进一步的数值计算给出了梳齿间距在0.010~0.025 mm 范围内、工作频率在300~420 GHz 范围内的开放式矩形梳齿慢波结构的具体尺寸。利用粒子模拟软件对一个设计结果进行了仿真，得到的工作频率验证了冷腔分析的结果。

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.