【作者】 郭炜；

【导师】 罗积润；

【作者基本信息】 中国科学院研究生院（电子学研究所） ， 物理电子学， 2006， 硕士

【摘要】 谐振腔（空腔谐振器）是微波器件与系统中的重要部件，在速调管等器件中得到了很成功的运用。当频率提高到毫米波段（如大气窗口的8mm波段），基于相对论电子效应的回旋管中，工作在高次模式的谐振腔，受到谐振频谱密集及模式竞争现象的严重影响，性能发挥受限。开放式谐振腔一定程度改善了这些问题，但具有缓变截面波导段的开放腔纵向尺度较大，不易组合运用，难以进一步提高器件的增益带宽积、功率和效率。 本文讨论一种新型模式选择复合开放式谐振腔。这种腔杂模抑制能力强、工作模式稳定性好、结构短小，可在短尺度上使用多腔构成簇腔群聚段。本文首先对这种腔的模式选择特性作较为详细的分析，利用Ansoft HFSS高频分析设计软件，对工作模式为TE₀₂₁／TE₀₃₁情况下腔中模式的谐振进行了数值模拟计算，计算表明，内腔边界位置设置和内腔壁开6个矩形孔能够将内腔中的TE₂₂₁和TE₅₁₁两模式的相对储能降低到普通圆柱腔时的58％和12％，有效地抑制了这两个竞争模式。 同时，为了使这种复合腔能够应用于毫米波回旋管器件，本文从设计的角度出发，分析这种腔结构中的公共腔壁具有有限厚度和轴向开漂移孔对腔中工作模式稳定性的影响，探讨在实际工程设计中补偿这种影响的手段。结果表明，合理调整复合腔内外腔的半径比值，能够有效改善工作模式的模式纯度和相对稳定性。 此外，对一套加工成形的簇腔模型进行了冷测模型设计，并使用网络分析仪测量了各个腔体的幅频响应。通过对冷测模型的计算机模拟以及对冷测数据的分析，我们找到了确定腔体工作模式TE₀₂₁／TE₀₃₁和竞争模式TE₂₂₁、TE₅₁₁谐振频率的方法。同时讨论了冷测状态和真实工作状态的差异，为这种簇腔结构的工程实践提供了可靠依据。更多还原

【Abstract】 Resonant cavity is an important part of microwave devices and system, which has been applied in klystron, magnetron and so on. In range of millimeter wavelength （such as 8mm）, resonant cavity operates in high order mode in gyrotron based on relativistic effect, where mode competition is a very important problem affecting its electrical feature and stability. Open cavity has some action for improving mode competition. But the open cavity is usually long along axial direction because of long tapering section, which limits its use through the combination of the several cavities to enhance gain, bandwidth, output power, and efficiency of Gyrotron.In this thesis, a new mode-elective complex open-cavity is discussed, which has the good feature for mode selection and suppression with a short length and can be used to form clustered cavity. The mode electivity of this cavity is studied in detail in order to understand its operating mechanism. The resonant characteristics of the TE₀₂₁/TE₀₃₁ as operating mode and the other competing modes in the cavity are numerically simulated and analyzed with Ansoft HFSS code. The results have shown that the relative stored energy of two main competing modes the TE₅₁₁ and TE₂₂₁ in the cavity can respectively be reduced to 58% and 12% of that in cylindrical cavity.In order to apply this new complex cavity in millimeter wave Gyrotron, the effects of thickening the cavity wall and constructing a pair of drift tube in the cavity on the operating mode stability for engineering design are analyzed. Some compensating methods for alleviating the effects are discussed, which shows that rationally adjusting the radius ratio between the inner and outer cavity in the complex cavity may effectively realize high purity and stability of the operating mode.In addition, a cold test model is designed based on a set of designed clustered cavities, the amplitude frequency response of each cavity is measured with network analyzer. Via the comparison of the simulation results of the cold test model with the cold test data of the model, a method for determining the resonant characteristics of the operating mode TE₀₂₁/TE₀₃₁ and the main competing modes TE₅₁₁ and TE₂₂₁ is tried. The difference between the cold test way and real operation status is discussed, which is useful for the application of this new complex cavity.更多还原