Abstract: Geometry, polarity of the exciting electrodes, and stray capacitance effect the performance of the thickness-shear mode acoustic wave sensor operating in electrolytes and solutions of biomolecules. In contrast to the mass-based response of the device operating in the gas phase, the response in a liquid is governed by factors including acoustoelectric, and fringing field effects, which are known to be active at the edges of the electrodes. The invention relates to an electrode having modified geometry to increase the edge length to raise the sensitivity of the device, and to enhance the sensor response.