Imaging of element excitations with spherical scanning

We review two conventional algorithms for aperture back-projection from spherical near-field data, with the goal of quantifying array-element excitations. The first algorithm produces that portion of the near field that radiates to the far field. The second algorithm divides out the element pattern prior to the transformation, and produces an estimate of the element excitations. We introduce a variation of this element-excitation algorithm that, for some arrays, can improve the fidelity of this conventional estimate. For the array geometries measured and simulated, this new algorithm shows dramatic improvement.