Multimode spherical hydrophone

An investigation is made of the multimode spherical hydrophone. The physical model considered in the present analysis is a piezoelectric ceramic spherical shell whose surface is sectionally electroded, with each section considered an electrically separated hydrophone. The induced voltage due to the incident acoustic wave is obtained for a radially poled ceramic shell. The maximum hydrophone sensitivities are calculated for both omnidirectional and dipole modes based on the present model, and the theoretical results are compared with the experimental results. The use of the multimode spherical hydrophone is found to be advantageous over the multimode cylindrical hydrophone in that (1) the resonant frequency of the omnidirectional mode of the spherical model is substantially higher in comparison with that of the cylindrical model for the same mean diameter, and (2) the sphere has identical dipole mode patterns in both directions of azimuth and elevation, whereas the cylinder has different dipole mode patter...