基于柱坐标系抛物方程的太赫兹目标RCS计算

RCS calculation of terahertz target based on parabolic equation in cylindrical coordinate system

针对太赫兹(THz)波段目标雷达散射截面(RCS)的计算问题,提出柱坐标系抛物方程模型的计算方法。基于柱坐标系中的电场通解式,利用三角函数的正交性分解各模式的激励系数,将抛物方程方法拓展到柱坐标系,得到柱坐标系中抛物方程的分步傅里叶求解形式。在此基础上,将目标等效为一系列的面元或线元,然后通过边界条件和场的迭代递推方法求解抛物方程,进而获得这一系列面元在传播方向某一截面上的散射场。数值算例表明,该方法能用于电大尺寸目标的RCS计算,相比于传统的抛物方程方法,克服了散射角度的限制,计算误差更小。

Aiming at the calculation of Radar Cross Section(RCS) of targets in Terahertz(THz) band, a parabolic equation model in cylindrical coordinates is proposed. Based on the general solution of electric field in cylindrical coordinate system, the excitation coefficients of each mode are decomposed by the orthogonality of trigonometric function. The parabolic equation method is extended to cylindrical coordinate system, and the fractional Fourier solution of parabolic equation in cylindrical coordinate system is obtained. On this basis, the target is equivalent to a series of surface elements or line elements, and then the parabolic equation is solved by the iterative recursive method of boundary conditions and field, and the scattering field of the series of surface elements on a certain cross section in the direction of propagation is obtained. The numerical examples show that this method can be u tilized to calculate RCS of electrically large targets. Compared with the traditional parabolic equation method, it overcomes the limitation of scattering angle and has smaller calculation error. This research is of great significance for fast target recognition and imaging in THz band.