Sk. Jeng, NEAR-FIELD SCATTERING BY PHYSICAL THEORY OF DIFFRACTION AND SHOOTING AND BOUNCING RAYS, IEEE transactions on antennas and propagation, 46(4), 1998, pp. 551-558
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.