A Novel Method to Investigate Dependence of SAW Resonator Sensor Signatures on Localized Surface Perturbations

We use a novel method to empirically investigate the dependence of SAW resonator signature on specific perturbation spots. We fabricated two-port SAW resonators and applied mass-loadings on several significant locations on the device surface using the BioChip Arrayer^TM, a commercially available micro-dispenser for biomolecules. Frequency characteristics are measured for each SAW resonator sample with a different deposition location for the receptor molecules which represent an acoustic perturbation to the SAW resonator cavity. We could verify that the sensor signature is strongly dependent on the location of these perturbations as well as the concentration of the receptor molecules. We assert that the degree of impact is closely related to the non-uniform acoustic energy distribution on the SAW resonator surface. This study will give insight into how to strategically create the detection layer for the modern SAW resonator sensors by locating the areas where the sensing layer should or should not be deposited.