带状注速调管多间隙扩展互作用输出腔等效电路的研究

Research on equivalent circuit of multi-gap output cavity for sheet beam extended-interaction klystron

带状注扩展互作用速调管(SBEIK)结合了带状注速调管与扩展互作用速调管的优势,在微波和毫米波真空电子器件中具有显著的技术潜力.本文提出了应用于SBEIK的五间隙哑铃型扩展互作用耦合腔输出回路的等效电路模型,获得了建立复杂多间隙扩展互作用腔的等效电路理论的方法.通过推导出的理论,快速确定了五间隙扩展互作用耦合腔的工作模式、谐振频率及间隙阻抗矩阵,由间隙阻抗的频率特性曲线快速估算出各模式对应的带宽,分析研究了耦合系数k以及Q e对于多间隙腔模式频率间隔及带宽的影响.此外,利用三维PIC仿真软件对相应的SBEIK五间隙输出腔高频特性进行了粒子模拟,结果表明,三维仿真获得的工作模式带宽特性与等效电路法计算结果基本一致,证明了本文所建立的等效电路方法的准确性和有效性.

Sheet beam extended interaction klystron, which has both the advantages of sheet beam klystron and extended-interaction klystron （EIK）, has become a key technique for developing high power microwave and millimeter-wave vacuum electron devices. An equivalent circuit of the five-gap output cavity for sheet beam EIK is proposed in this paper. The mode, resonant frequency, and the cavity impedance can be calculated by using the method of equivalent circuit efficiently. The bandwidth could be estimated by the curve of cavity impedance versus frequency. The influences of coupling coefficient （k） and external Q （Q e ） on mode frequency interval and bandwidth are discussed. In order to test and verify the method of equivalent circuit, the 3D-PIC simulation of output cavity is conducted. The bandwidths under different values of external Q are calculated in two ways. The results accord well with each other. It is confirmed that the method of equivalent circuit for sheet beam EIK is accurate and credible. This is useful for the design of the whole tube.