HBAR‐Spectroscopy Used for Materials Characterization

Resonance spectra of a High‐overtone Bulk Acoustic Resonator (HBAR), consisting of a substrate plate and a piezoelectric transducer, can be used to evaluate density, elastic constants and mechanical loss of the substrate material. It is shown that density and elastic constants can be determined independently from the spacing of the parallel resonant frequencies whereas mechanical loss can be assessed from the parallel resonance Q‐value. The accuracy of the presented method is evaluated though a series of numerical simulations based on an equivalent circuit model. Application to the characterization of some industrial materials is discussed.