Multiplicative receiving arrays

The performance of arrays in which the outputs from two groups of elements or sections are multiplied together is studied from the points of view of directional patterns, directional discrimination and signal/noise performance. It is shown that whereas, in ordinary linear arrays, these three considerations are usually all determined by the directional pattern, yet in multiplicative arrays they are all three quite distinct and often unreconcilable with one another. A comparison with super-directive arrays is also made, and an example is given of a possible practical application of the multiplicative array in an underwater echo-ranging system using electronic sector scanning.