TIME-DOMAIN PHYSICAL-OPTICS

In this paper, we extend the concept of the frequency-domain physical- optics approximation to the time domain, and use it to determine some significant properties of large reflector antennas. When this method i s used to determine the equivalent surface-current density on the refl ector, the effects of time-delayed mutual coupling between points on t he surface are ignored. Consequently, many of the numerical limitation s found in other conventional time-domain techniques are avoided, eg., boundary-truncation error, interpolation error, numerical dispersion error, numerical instability, error accumulation with time marching, e tc. More significantly, this method requires relatively small amounts of computer memory and CPU time. Several applications to the transient analysis of pulsed radar systems are given.