三模重叠双间隙耦合腔型输出回路的仿真设计

Simulation and design of three-mode overlapped two-gap coupled cavity type output circuit

为扩展速调管输出回路的带宽,进一步分析了双间隙耦合腔的模式重叠理论,说明了实现三模重叠的可能性,采用等效电路法计算了三模重叠双间隙耦合腔型输出回路的阻抗频率特性。以中心频率3GHz的输出回路为例,建立了3维计算模型,给出了设计这种输出回路的步骤和结构参数。用场分析法计算了间隙阻抗频率特性,结果表明:此输出回路2 dB相对带宽接近15%,加载滤波器后1.5 dB相对带宽可达19.3%。

In order to enhance bandwidth of output circuit for klystron, the theory of overlapped mode is analyzed. Possibility of overlapped three-mode is illuminated. Gap-impedance frequency distribution for three-mode overlapped two-gap coupled cavity type output circuit（TTCC） is calculated via equivalent circuit method. Taking a TTCC with 3 GHz center frequency for instance, 3D models for calculation are set up, and steps in designing this kind of output circuit are particularized. Parameters of structure are given. Relative bandwidth of 2 dB reaches 15 %, and 19.3% of 1.5 dB is obtained by loading a filter through calculating gap-impedance frequency via field analysis method.