螺旋带色散特性和耦合阻抗的精确计算

Precise Calculation of the Dispersion and Coupling Impedance of Tape Helix

应用一种改进的计算螺旋带色散和耦合阻抗的方法,对面电流密度进行Chebyshev多项式展开后,去除了螺旋带上的面电流密度假设。在介质的高阶径向分层时为了避免高阶矩阵的求逆运算,采用转移矩阵和连接矩阵处理边界的场匹配。编写可径向任意分层的普适性程序,计算了螺旋线行波管的一些典型结构。研究表明:该理论的计算结果与实验结果有很好的一致;谐波次数以及面电流Chebyshev展开的项数完全可以依据结果的收敛性进行选取;分层的数目主要与结构的径向规则程度有关,径向越不规则,所要求的分层数目越多。

An improved method for evaluating the dispersion and coupling impedance of a tape helix is utilized. The assumption about the surface current density distribution on the tape is avoided by expanding it in a series of Chebyshev polynomials. The propagation matrix and jump matrix are introduced when the dielectric layer is stratified. A program has been written to analyze some typical examples. It is found that the results obtained by computing and measuring agree to good accuracy. The maximal orders of spatial harmonic and Chebyshev expansion can be specified to ensure the convergence of the results. The number of the stratified dielectric depends on the degree of radial uniformity： the more uniform the dielectric, the less the number.