中文摘要：

利用等效电路理论和网络传输矩阵理论设计出了可承受平均功率10kW以上的3mm回旋行波管的输入输出窗。并用三维高频结构仿真软件HFSS和CST—MWS模拟结果与数值计算结果进行了比较，三者吻合得很好。在W波段驻波系数小于1．2的情况下，得到盒型窗输出带宽12．4GHz（13．2％）；三层介质矩形窗输出带宽为18，8GHz（20％）。本文所推导的理论结果可直接运用于更高频段高频窗的设计中。

英文摘要：

A high-frequency millimeter-wave window, which applied to the 3 mm gyrotron Traveling Wave Tubes and is capable of passing average power outputs of more than 10kW, was designed by using microwave equivalent circuit and transfer matrix. Three-dimensional simulation software HFSS and CST-MWS were used to simulate and investigate it, The simulation results agreed with each other very well. The results show that, when VSWR 〈 1.2 in the W-band, the pillbox window＇ s bandwidth can reach about 12.4GHz, and it reaches about 18.8GHz for the three-layer ceramic material rectangle waveguide window. The ideas and the theory can be easily applied to those in higher frequency.