考虑螺旋带厚度的翼片加载螺旋线慢波结构的理论分析

Study of helical slow-wave structures with vane-loaded taking account of the radial thickness of the helix

翼片加载螺旋线慢波结构广泛应用于大功率、宽频带行波管中。首次将考虑螺旋带径向厚度的螺旋带模型应用于翼片加载螺旋线慢波结构,将离散的夹持杆等效为一系列连续的介质层,各层取不同的径向相位常数,得到了实用的色散方程和耦合阻抗表达式。利用导出的方程对实际行波管的螺旋慢波结构进行计算,计算结果与测量结果具有良好的一致性。分析了螺旋带厚度、介质分层数以及外壳半径对计算结果的影响,结果表明考虑螺旋带厚度能大幅提高计算精度。

The vane-loaded helical slow-wave structures is widely used in high power, broadband traveling-wave tubes (TWTs). Taking the radial thickness of the helix into account, the tape helix model was suggested for the vane-loaded helical slow-wave structures. By taking the discrete supports bars into some continuous dielectric tube regions, the dispersion equations and the expressions of interaction impedance were obtained. Besides, the radial propagation constant of every layer in the dielectric-loaded region was differentiated. Some helical slow-wave structures of TWT were calculated by the derived equations. The calculated results accord with measured values very well. Compared with measured values, the calculated results of the model considering the radial thick of the helix is of higher precision than those of not considering the thick of helix.