A Lamb wave electrostatic voltage sensor

Lamb-wave electrostatic voltage sensors have been fabricated using planar technology incorporating a standard interdigital transducer (IDT) array (for generation and detection of the Lamb waves) and a capacitative electrode placed on each side of the sensor substrate in the region of wave propagation (for applying the DC potential). The Lamb waves/modes generated for substrate thicknesses of 50, 102, and 254 μm were identified using theoretical dispersion curves. The modes were of both the antisymmetric and symmetric variety. The electrostatic voltage sensitivity, as measured in a SAW (surface acoustic wave) oscillator configuration, was double that of an equivalent Rayleigh device. Insertion losses, short- and long-term oscillator stability, and oscillator thermal sensitivity are reported