Antenna - aperture distributions from holographic type of radiation-pattern measurement

Two methods are presented for determining antenna aperture distributions from the magnitudes (moduli) of radiation patterns. Antennas under test are measured in the presence of fixed-reference antennas. Invoking the principle of holography, the radiation-pattern measurements are arranged so that all the required information can be obtained without having to make any phase measurements. The methods are illustrated with laboratory experiments, performed with acoustic antennas, for which the aperture distributions are determined to an estimated accuracy of within 5%.