复杂目标的太赫兹波近场RCS快速计算

在太赫兹频段，散射目标大部分处于近场区域，远场计算方法已经不再适用，为此该文推导了近场雷达散射截面(RCS)的计算公式。针对太赫兹频段近场条件下，物理光学法(PO)由于面元数量巨大引起的遮挡判断耗时过长，以及图形电磁学(GRECO)以像素为计算单位计算误差过大的问题，该文提出一种以面元为计算单位，以像素为遮挡判断单位的复杂目标太赫兹波近场RCS的快速计算方法，该方法在保证计算精度的基础上，大大降低了遮挡判断的计算复杂度和时间。最后，以标准目标体平板、球体以及复杂目标体卫星在不同距离下的雷达散射截面的计算为例，验证了该方法的有效性和准确性。

Fast Computation of Near Field RCS of Complex Objects in Terahertz Band

In the terahertz band, most targets are in the scope of near field. The computation method of the far field RCS is not applicative, therefore, the computational formula of the near-field Radar Cross Section (RCS) is deduced. The occlusion judgment consumes a long time in the Physical Optics (PO) method because of the huge amount of surface elements, and the computational error is unacceptable in the GRaphical-Electromagnetic COmputing (GRECO) method using pixels as the unit of calculation. To deal with the above problem in the PO method and the GRECO method, based on the computational parameters pretreatment, a fast computational method of near field RCS using surface element as the calculating unit and the pixel is used as the occlusion judgment unit is proposed for the complex objects in terahertz band. The method ensures the calculation accuracy, and greatly reduces the computational complexity, and the time consumption of occlusion judging. The calculation of the near-field RCS produced by a square plate, a sphere and a satellite is studied in terahertz band. The results show that this method is efficient and accurate.