具有任意槽的矩形波导栅慢波结构高频特性的研究

将任意形状槽的连续轮廓近似用一系列相连的矩形阶梯近似，利用各阶梯面上导纳的匹配，以及槽与互作用区边界场的连续与匹配条件，获得了具有任意槽的矩形波导栅慢波结构的色散方程和耦合阻抗的表达式，并进行理论上的验证.加工制作了矩形槽波导栅模型，冷测表明理论值与测量值相吻合.分别求解几种特殊槽形矩形波导栅慢波结构的色散特性及耦合阻抗，其中，三角形结构的色散和耦合阻抗均最弱，而倒梯形结构色散最强，耦合阻抗最大. 关键词： 矩形波导栅 任意槽 色散特性 慢波结构

Study of high frequency characteristics of the rectangular waveguide grating slow-wave structure with arbitrary grooves

The rectangular waveguide grating slow-wave structure (SWS) is a new type of RF system of millimeter traveling wave tube (TWT). However, it has narrow pass band. For the purpose of broadening the bandwidth of this circuit, it is necessary to study the influence of groove shapes on the characteristics. In this paper, the dispersion equation of a rectangular waveguide grating SWS with arbitrary grooves is derived by means of an approximate field-theory analysis, in which the continuous profile of the groove is approximately replaced by a series of steps, and the field continuity at the interface of two neighboring steps and the matching conditions at the interface between the groove region and the interaction region are ensured. The cold test on dispersion characteristics of a rectangular groove SWS shows that the theoretical results are in good agreement with the experimental results. We have calculated the dispersion characteristics and the coupling impedance of the slow-wave structures with some special groove shapes. It shows that the dispersion characteristics of the triangle-groove structure is the weakest and the coupling impedance of it is the lowest, while the dispersion characteristics of the inverted-trapezoid-groove structure is the strongest and the coupling impedance of it is the highest.