Prediction and measurement of near fields for antennas on structures

Techniques for predicting near fields of antennas on limited ground planes, aircraft and other vehicles, have-been developed. Wire grid modelling is used to calculate the current distribution over the metal structure, from which the fields close to the surface can be found. These field values could then be used in a quasi-static analysis to predict aperture penetration fields, with application to electromagnetic compatibility. A new form of electric field probe with an optical fibre link has been developed, which has been used to obtain experimental measurements to compare with the theoretical predictions. The agreement obtained is very close, confirming the theory and showing that the probe gives unperturbed and accurate measurements.