A possibility of ball SAW sensors

摘要

A surface acoustic wave (SAW) excited by a line source with a finite length on a solid ball propagates along the great circle perpendicular to the line source without beam spreading due to the diffraction. We experimentally confirmed the propagation of collimated SAW's on a glass ball, 80mm in diameter. We fabricated an IDT with a ZnO piezoelectric thin film on a ball of silicon nitride, 12.5mm in diameter, and evaluated the frequency characteristics.