VALIDATION OF, AND LIMITATIONS ON, THE USE OF NEC-4 FOR RADIATION FROM ANTENNAS BURIED WITHIN A HOMOGENEOUS HALF-SPACE

Abstract

The use of the computer program NEC-4 for the simulation of radiation from buried antennas is considered. NEC-4 uses the “exact” Sommerfield integral formulation for stratified media (in NEC-4, re-stricted to an homogeneous half-space). Although the formulation is rigorous, certain approximations have to be made for numerical implementation. The formu-lation, and some of these issues, is outlined in the paper. Several validation examples comparing results computed using NEC-4 and results available in the lit-erature are presented for antennas buried in various typical media, including ground, fresh water, and the sea. Satisfactory agreement has generally been obtained; where differences have been noted, we have able to explain most in terms of approximate implementa-tion issues.