Evaluation of Method of Moments Codes: University of Houston Junction and Numerical Electromagnetic Code.

Abstract : The principal goal of the Electromagnetic Compatibility (EMC) Project is to minimize exterior electromagnetic interference (EMI) problems during the life-cycle of Navy surface ships. An important aspect of mitigating exterior EMI problems is the characterization of antenna performance. At the present time, for shipboard MF and HF (2 to 30 MHz) antennas, there exists two techniques for performing a topside antenna study: brass scale modeling and numerical modeling. Brass scale models have a few drawbacks: they are time-consuming to build, difficult to rapidly modify, troublesome to accurately measure near fields on scale models, and they are somewhat limited in their application. This report is an evaluation of the progress in development of two advanced computer programs for antenna modeling. One is the performance of the JUNCTION Code, under development at the University of Houston, and the other is the performance of the Numerical Electromagnetic Code - Version 4 (NEC4) being developed at the Lawrence Livermore National Laboratory. Electric Field Integral Equation (EFIE), Magnetic Field Integral Equation (MFIE), Method of Moments (MoM), Antenna modeling.