Patent ID: 8726734

Claim:
A shear wave generator comprising: a first piezoelectric element having a first polarity in electrical communication with a first electrode pair; a second piezoelectric element having a second polarity in electrical communication with a second electrode pair, wherein the second polarity is an inverse of the first polarity; a boundary layer disposed behind both the first piezoelectric element and the second piezoelectric element; and an excitation signal generator in electrical communication with the first electrode pair and the second electrode pair, wherein the first piezoelectric element vibrates in a first direction and the second piezoelectric element vibrates in a second direction in response to an excitation signal, wherein the first piezoelectric element has a first wave generating surface and the second piezoelectric element has a second wave generating surface, the first and second wave generating surfaces aligned and sized such that a shear wave is generated in response to an excitation signal, wherein the shear wave has a direction of vibration perpendicular to a wave direction of the shear wave.