NEAR-FIELD SCATTERING BY PHYSICAL THEORY OF DIFFRACTION AND SHOOTING AND BOUNCING RAYS

This paper will propose a method to compute the near-field RCS and Dop pler spectrum of a target when the distances to antennas are comparabl e to the target size. By dealing with a small piece of the target surf ace at a time, the transmitting antenna, and the receiving antenna are in the far-field zone of the small piece of the induced currents, And the electromagnetic field produced by this small piece of induced cur rents can be written as a spherical wave, Sum up all spherical waves p roduced by every small piece of induced currents and we can obtain the total scattered field at the receiving antenna, The physical theory o f diffraction (PTD) and the method of shooting and bouncing rays (SBR) are modified to evaluate the received signals, Numerical results base d on these techniques are obtained and discussed, The formulation in t his paper applies the simple concepts of ''equivalent'' image and vect or effective height, which are believed to be novel.