Focused phased array measurements

Measurements describing the patterns of a linear phased array antenna which has been electronically focused to a point in the Fresnel region, located a few aperture widths distance from the array face are given. The measurements were taken inside a building with no effort made to reduce extraneous reflections. A comparison of the results with patterns taken on a conventional far-field range reveals that the estimated measurement accuracy of the level of the first few sidelobes is on the order of
\pm1
dB. The technique provides a good performance monitor check, is easily implemented, permits an indoor measurement, and offers the advantage of simplicity over far-field measurements.