High-performance dipole acoustic transmitter

Abstract

A disclosed high-purity dipole transmitter has a longitudinal axis, an oscillation axis, and a side axis, each of the axes being mutually orthogonal. The transmitter includes an outer shell having external surfaces for displacing fluid along the oscillation axis. The transmitter also includes a reaction mass positioned inside the outer shell. The transmitter also includes an electromagnetic actuator that drives the outer shell relative to the reaction mass. The transmitter also includes a pair of matching springs separated along the longitudinal axis, where each spring is coupled between the outer shell and the reaction mass to enable compliant dipole motion of the outer shell along the oscillation axis while suppressing motion along other axes. Each spring includes a beam arrangement with each beam extending lengthwise in a direction parallel to the side axis and being thinnest in a direction parallel to the oscillation axis. The outer shell, the reaction mass, the electromagnetic actuator, and each spring, have mirror symmetry in a plane that includes the oscillation axis and the longitudinal axis, and have mirror symmetry in a plane that includes the side axis and the longitudinal axis.