A FINITE-DIFFERENCE TIME-DOMAIN NEAR ZONE TO FAR ZONE TRANSFORMATION

The finite-difference time-domain (FDTD) method has been in use for many years. Early applications were primarily in areas of electromagnetic pulse response and penetration of electromagnetic fields into various materials including human tissues. For these applications the electromagnetic fields within or adjacent to the scattering object were of interest. More recently, FDTD has been applied to analyze scattering from radar targets, with the desired result being the far zone scattered field. While efficient methods for transforming from near zone to far zone in the frequency domain are well known and commonly applied, a complete description of a method to efficiently transform FDTD results to the far zone in the time domain has not appeared previously in the literature. In this paper the details of such a method are presented. For validation, far zone scattering results for a flat plate are transformed to the frequency domain and compared with the method of moments.