Surface-patch modelling of a Wheeler cap for radiation efficiency simulation of a small loop antenna with NEC2

The Wheeler cap method is an easy and accurate way to measure the radiation efficiency of small antennas, and has been analysed by other investigators using a wire-grid model. However, it is more reasonable to use a surface-patch model for the cap instead of the wire-grid model. This would avoid the inevitable leakage from the wire grid. The authors confirm the validity of the simulation using the surface patch for the Wheeler cap with NEC2 (numerical electromagnetics code 2 developed by Lawrence Livermore National Laboratory)