The modeling of the alignment sensitivity of a SAWR strain sensor to applied strain

In this paper we present the theoretical performance of a one-port Surface Acoustic Wave Resonator (SAWR) strain sensor fabricated on AT-X quartz. The theoretical strain sensitivity of the SAWR sensor is calculated using the effective surface acoustic wave velocity for various SAW substrate stress states. The stress state is varied by rotating the SAWR strain sensor´s substrate relative to an applied strain field. Theoretical strain sensitivity values are then compared to experimental results, with good correlation observed. It is shown that the SAWR strain sensitivity can be predicted and controlled by rotation and alignment of the SAWR substrate relative to the dominant strain component.