螺旋波纹波导的传输特性

 根据螺旋波纹波导的传输耦合方程，取输入模式为TE₁₁，由螺旋波纹波导模式耦合规则得到输出模式为TE₂₁，由此给出耦合方程的具体形式。用“迭代法”简化耦合方程，并进行数值分析，得到了波导波纹周期对传输特性的影响；利用简化后耦合方程解的解析式计算了螺旋波纹波导工作模式中各场幅值的比例关系。计算结果表明：在工作频段内螺旋波纹波导中场结构是一种混合模，以TE₂₁模为主，其群速基本接近常数，可以和电子注在很宽的频带内产生互作用，为注波互作用的计算提供了依据。

Transmission characteristics for wave-guide with helical corrugation

According to the general coupled-wave equations of wave-guide with helical corrugation,selecting the import-mode TE_(11),the coupled mode TE_(21) is gained.Based on the rules of mode coupling in helical wave-guide the determinate formula for coupling equation is obtained and analyzed.Using the iterative method can simplify the coupling equation.At the same time,analyzing the result can give the impact of transmission characteristics by the periods of helical wave-guide.The analytic formula of simplied coupling equation is employed to operate the rate of amplications in the work mode of helical wave-guide.The result indicates that the hybrid mode can be given within work frequencies,in which the main mode is TE_(21).The value of group velocity of hybrid mode is a constant number.And the band will be wide,when it interacts with beam.All of the analysis gives the evidence of beam-wave interaction.