Experimental technique for characterizing arbitrary aspect ratio piezoelectric resonators

The electromechanical coupling coefficient k is the most important parameter for the characterization of a piezoelectric material and for the design of electromechanical devices. Standard resonance technique for measuring the k value is based on one-dimensional approximation, which needs to use samples having extreme geometries. For small size crystals and/or due to geometrical constraints in many devices, piezoelectric resonators may not be made into such extreme geometries. An averaging scheme has been developed to tackle this challenging experimental task, and the so obtained k values agree well with theoretical predictions of k values for arbitrary aspect ratio resonators.