Transducer assembly and method for radiating and detecting energy over controlled beam width

Abstract From the Canadian patent

A transducer assembly capable of radiating and detecting energy over a controlled beam width around a selected axis is formed by a piezoelectric element mounted in a cylindrical resonant cavity defined by a Helmholtz chamber. The resonant chamber has an energy emitting end wall positioned normal to the selected axis and is arranged to emit energy symmetrically around the axis at the predetermined radial offset distance therefrom. The energy emitted from the chamber through the end wall sums to form along and around the selected axis a beam-like pattern of controlled width the beam width, being controllable as a function of the offset distance and the energy wavelength. In one embodiment, …