Use of Attenuation and Phase Delay Characteristics of SAW to Measure Air-Gap Height (Technical Notes)

The attenuation and phase delay characteristics of a SAW which has been perturbed by a metallic plane above the surface of a piezoelectric delay line have been theoretically computed and experimentally measured. These measurements provide a diagnostic tool for determining the height of an air gap and for determining the minimum achievable air gap for a particular supporting structure.