A 2-DIMENSIONAL TIME-DOMAIN NEAR-ZONE TO FAR-ZONE TRANSFORMATION

In a Previous paper, a time-domain transformation useful for extrapolating three-dimensional near zone finite-difference time-domain (FDTD) results to the far zone was presented. In this communication, the corresponding two-dimensional transform is outlined. While the three-dimensional transformation produced a physically observable far zone time-domain field, this is not convenient to do directly in two dimensions. However, a representative two-dimensional far zone time-domain result can be obtained directly. This result can then be transformed to the frequency domain using a fast Fourier transform, corrected with a simple multiplicative factor, and used, for example, to calculate the complex wide-band scattering width of a target. If an actual time-domain far zone result is required, it can be obtained by inverse Fourier transform of the final frequency domain result.