Analysis of thin rod flexural acoustic wave gravimetric sensors

An analysis of thin rod flexural acoustic wave gravimetric sensors is presented. The diameter of the thin rod is much less than a wavelength. The lowest order flexural acoustics mode, F11, is of interest. For small added masses, the calculated mass sensitivity is −1/(2ρa), where ρ is the density and a is the radius of the thin rod. Measurements of velocity dispersion of the F11 mode in 21-μm-diam gold wires are shown to agree well with the theoretical calculation. Devices based on thin rods are shown to potentially have the same advantages as plate-mode gravimetric sensors.