Theory of near-field phased arrays for electromagnetic susceptibility testing

The feasibility of using a near-field array for electromagnetic susceptibility testing is studied. The basic objective is to control the element weighting such that a plane wave is generated within the test volume. The basic theory is developed for arbitrary array geometries, and numerical results are obtained for finite planar arrays. A general near-field array synthesis technique is developed, and the technique minimizes the mean square error in the test volume while constraining the array excitations. The constraint prevents large currents and is useful in minimizing the fields outside the test volume. The basic idea looks promising, but some practical considerations, such as bandwidth and angular scanning limitations, require further theoretical and experimental investigation.