回旋速调管输入耦合器分析与设计

 对Ka波段工作模式为TE₀₁模和TE₀₂模的两种回旋速调管的输入耦合器进行了详细研究，利用模式匹配理论和HFSS建模仿真计算了内圆柱腔和外同轴腔的尺寸；提出了一种与软件计算相结合的模式纯度计算方法，对内腔工作模式纯度、内外腔能量分数进行了计算。内腔侧面上的耦合缝的大小、角向位置都直接决定外同轴腔内的TE_m11模向内圆柱腔的TE_0n1模的耦合情况。针对耦合缝与输入波导成45°和0°分布两种情况，研究了耦合缝长、宽和角向偏移，以及内外腔频差对频率、Q值及内腔能量分数的影响。分别设计了Ka波段内腔工作模式为TE₀₁₁、外腔为TE₄₁₁和内腔TE₀₂₁、外腔TE₈₁₁的两种输入耦合器，并利用矢量网络分析仪对内腔工作模式为TE₀₁₁的耦合器进行了冷高频测量，测得频率为34.257 GHz，与计算结果34.300 GHz仅相差43 MHz。

Analysis and design of the input coupler of a gyroklystron

The gyroklystron is a high power, high gain, and high efficiency millimeter wave amplifier. Its circuit usually comprises of 4 or 3 stagger-tuned cavities. The input coupler is the first cavity of the circuit and must exhibit reasonable coupling strength between the TE10 mode in rectangular waveguide and the desired TE011 or TE021 circular cavity mode with high purity. The theoretical analysis and HFSS simulation of the input coupler are presented. Mode matching technology is used to calculate the size of coaxial and cylindrical cavities. A new method, combining theory and HFSS, is presented to calculate the purity of working mode. Some results are obtained through the study of the orientation, width and length, angular offset of the apertures. The results show that 45°orientation is bett