method of perturbation meaning in English

扰动法
摄动法
微扰法

This paper studied the dispersion and the field distribution of the wave - guide with helical corrugation operating in 8mm wave band . the main works of this dissertation are listed as following : 1 . based on the theory of coupled - wave , using the method of perturbation , the coupled - wave equations are derived and the rule of coupling is gotten . 2
2 .利用螺旋波纹波导的耦合波方程和模式耦合规则,得到波导色散方程,利用visualfortran平台编程进行数值模拟,分析相关物理参数对色散特性的影响;对波导的行波幅值耦合方程进行数值模拟,从而简化了耦合方程,在此基础上利用visualfortran平台编程进行数值模拟,分析螺旋波纹波导的场分布情况。