高功率回旋行波管新型输出渐变段的设计

摘要

A new output-taper for Ka-band high power gyro-TWT is designed by a function of sine and cosine and using the coupled wave equation to analyze the radius changing circular waveguide.Using the MATLAB code and software HFSS,we analyze the transmission,the reflection coefficient and the coupling coefficient to TE02 mode and TE03 mode.When the length is 80mm and the diameter changes from 14 mm to 32 mm,the results indicates its transmission coefficient more than-0.000 52 dB,reflection coefficient less than-65 dB,mode purity more than 0.995,the coupling coefficient to TE02 mode and TE03 mode less than-40 dB.Compared with Dolph-Chebyshev output taper,when the length and diameter are the same,the new output taper's transmission,reflection coefficient and mode purity are superior than those in 30 GHz to 33 GHz.The results of cold test for the test-sample show that S11＜-30 dB and S21＞-0.3 dB.%利用正余弦拟合的方法和半径渐变波导的耦合波理论设计出一种Ka波段TE01模回旋行波管新型输出渐变段.通过Matlab数值计算和HFSS仿真优化,研究了该新型渐变段的反射系数、传输参数、模式纯度、对杂模的耦合等性能指标.计算结果表明:在长度为80 mm、口径由14 mm变化到32 mm的情况下,在30～33 GHz该新型渐变段的传输参数大于-0.000 52 dB,反射参数小于-65 dB,模式纯度大于0.995,对TE02模和TE03模耦合在-40 dB以下.在等长度和等口径下,与Dolph-Chebyshev渐变段进行比较,结果显示在30～33 GHz内,新型渐变段比其传输参数更好、反射参数更小、模式纯度更高等.测试样品的冷测实验结果为在28～35 GHz范围内,其反射参数小于-30 dB,传输参数大于-0.3 dB.