BEAM PATTERN FORMULATION AND ANALYSIS FOR WIDE-BAND BEAMFORMING SYSTEMS USING SPARSE ARRAYS

This communication addresses the evaluation of beam patterns (BPs) in active beamforming systems using wide-band signals and sparse arrays. Usually, BPs are computed under a narrow-band hypothesis according to which a simple analytical and closed-form equation can be used. In thi s communication, with reference to imaging applications, the BP for wi de-band signals is redefined on the basis of beam-signal maxima, and a quasi-closed form of the analytical formulation is achieved for any i nter-element spacing. It can be noticed that, under wide-band conditio ns, the height of these grating lobes can be predicted and that depend s only on the pulse duration and on the number of array elements, but does not depend on the spacing between elements. As a result, the prop osed quasi-closed form supports the design of very sparse arrays that show beam-pattern profiles of great interest for imaging applications. (C) 1997 Elsevier Science B.V.