Aperture integration and GTD techniques used in the NEC reflector antenna code

The numerical electromagnetics code (NEC) reflector antenna code has been sent to over 50 companies, government agencies, and universities. It is known to be in extensive use by several of these organizations. The theory and computational techniques used in the code, which has the capability for both near field and far field computations for reflector antennas with paraboloidal surfaces are described. A key feature of the code is its capability to calculate complete patterns for a general reflector rim shape.