Underwater parametric transmission with a linear array

The modeling of parametric transmission by means of the spatial Fourier formalism (also called the angular spectrum method) is recalled. The secondary field can be estimated at any distance of the antenna. Various geometries of the transmitter can be also taken into account, including elongated antennas that feature a wide aperture in one plane. The relevance of the theoretical model with such geometry is tested with a linear array used as a parametric transmitter in an underwater application. Numerical estimations are compared with experimental measurements. In addition, the expected slight variation of the parametric efficiency with the relative phasing of the primary signals is experimentally observed.