Array gain for a circular array mounted on a sphere

Circular arrays used in underwater acoustic systems for passive surveillance often have sensors mounting around a rigid spherical baffle. In this paper, a model is introduced for computing the array gain of such an array based on the concept of phase mode, which incorporates baffle scatter using hard sphere scattering theory. Some illustrative examples show the weak mode order for some frequencies result a local minimum array gain. Therefore, array gain with white noise gain constraint can be used to choose the right modes to generate desired characteristics of beam pattern for practical application.