The modal projector.

The superposition of acoustical modes radiated from a transducer can provide directionality from a compact projector. This paper presents the foundation, as well as examples, of piezoelectric ceramic, piezoelectric single crystal, and magnetostrictive versions of this "modal projector." Measured and analytical, as well as finite element analysis modeled, results show good agreement and establish this transducer as a viable source of intensity with the advantages of an improved directivity index, reducing the power needed from a compact source.