翼片加载螺旋线慢波结构特性研究

【作者】 张勇；

【导师】 莫元龙；

【作者基本信息】 电子科技大学 ， 物理电子学， 2002， 硕士

【摘要】 在现代国民经济部门如通讯、雷达、航空航天等，以及现代化军事装备如雷达、干扰机等中，宽带大功率行波管的应用具有举足轻重、无可替代的作用。螺旋线是宽带行波管中一种重要的慢波结构，它具有结构简单、易于制造、良好的色散特性、较高的耦合阻抗等一系列优点。对它的研究有助于改善它的慢波性能，实现行波管的计算机辅助设计(CAD)，提高行波管的总体性能。 本文利用场论求解的方法，采用螺旋导电面模型，将实际的螺旋线看成一个螺旋导电圆筒，圆筒上沿螺旋线前进的方向理想导电，而与其垂直的方向完全不导电，建立了翼片加载螺旋线慢波结构的导电面模型，得到了各区的场表达式。并进一步推导了实用的色散方程、耦合阻抗和衰减常数表达式。 采用螺旋带模型，假设螺旋线由金属带绕成，在圆柱坐标下写出螺旋线内、外两区中场的一般展开式，然后从假定的螺带电流出发求出展开式中的幅值系数。推导出了相应的色散方程、耦合阻抗和衰减常数表达式。 利用导出的方程，采用可视化技术，在Visual C++环境下，开发了螺旋慢波结构高频系统CAD软件：Helix，并成功的应用于行波管CAD集成环境软件包中。对实际行波管用螺旋慢波结构进行计算，并将色散关系、耦合阻抗、衰减常数的测量结果与导电面模型、螺旋带模型的计算结果进行了比较，得出了相同条件下，螺旋带模型优于导电面模型的结论。对螺旋带模型，分析了两种不同电流假设对色散特性的影响，并计算了不同夹持杆介电常数、不同管壳半径对色散特性的影响。 采用行波法对翼片加载螺旋慢波结构的色散特性进行了冷测实验，测试结果验证了理论分析的可靠性。更多还原

【Abstract】 The broad-band and high power traveling-wave tube(TWT) is very important in the modern military equipments such as Radar > jammer etc. The Helical slow-wave structures find wide application as RF interaction structures in the traveling-wave tubes. It has many advantages such as the simple structure, excellent dispersion characteristic and the high interaction impedance.First of all, the field theory based on the sheath model is used to study the characteristic of the helix in this dissertation. An actual helix is regarded as the helical conductive cylinder. By means of this model, the utility dispersion equation, the interaction impedance and the attenuation constant are obtained.Besides, the tape helix model is suggested too. In this model, the fields of the inside and outside helix have been expanded by the space harmonics, and then the expanded coefficient can be sovled from the given tape current utlizing the condition on boundary. Moreover, the dispersion equations, as well as the interaction impedance and the attenuation are worked out."Helix", a CAD software on the helical slow-wave structure is developed by the derived equations and the visual technology under Visual C++, and it is used successfully in TWT CAD software packet. Some typical helical slow-wave structures of TWT are calculated by the derived equations. The calculating results on the sheath and tape model are compared with those of the measurements. It is shown that the tape helix model is better than the sheath model under same conditions. The influence on dispersion characteristic is analyzed for two types of hypothesis current, the different permittivity of the dielectric support and the different radius of the metal envelope.The dispersion characteristic of a vane-loaded helical slow-wave structure isinvestigated experimentally by the travelling wave method. The "cold" test results are in good agreement with the theoretical results.更多还原