有限磁场中等离子体通道天线的辐射特性分析

Analysis on Radiation Characteristic of Plasma Channel Antenna in a Finite Magnetic Field

为了弥补现有高功率微波武器辐射天线的不足,提出了等离子体通道天线(PCA),研究了该天线的辐射特性。根据PCA的工作原理,将PCA等效为电子在横向旋转、轴向漂移的均匀冷磁化等离子体束,且认为该等离子体束的横截面为沿轴向不改变的圆形;推导出了一般性天线的辐射方向函数;结合麦克斯韦方程和本构关系,得出了PCA的色散方程,求出PCA的表面波波矢。重点讨论了PCA的辐射特性随等离子体密度、天线长度、半径及纵向速度的变化,得出一些有益的结论,为PCA的实现打下坚实的理论基础。

In order to cover the shortage of the antennas for high power microwave weapon currently, the idea of plas- ma channel antenna （PCA） is presented. The radiation characteristic of PCA is researched. Based on its operation princi- ple, the PCA is equivalent to uniform cold magnetized plasma beam, which is assumed to be gyrating transversely and drifting longitudinally. The cross-section of the plasma beam is considered as a circle and the shape is invariant along with axis. The directivity functions of generalized antenna are derived. The dispersion equation of PCA is deduced from Maxwell~ equations and constitutive relations. The surface wave vector of PCA is achieved. The variations of radiation characteristic with plasma density, antenna length, antenna radius and longitudinal velocity are emphatically discussed. Some useful conclusions are obtained, which gives a solid foundation for practical application of the idea. Key words： PCA（ Plasma Channel Antenna） , Finite magnetic field, Radiation characteristic