Sensitivity analysis for Love mode acoustic gravimetric sensors

An approximate mass sensitivity formula for Love mode sensors is presented. The optimal thickness of the guiding layer, at which the sensitivity, Sfm is maximum for a given frequency or wavelength is obtained. The (Sfm)max can be expressed as −k0/ρ1λ1, where ρ1 is the density, λ1 is the wavelength of the surface transverse wave of the substrate, and k0 is a coefficient determined by the ratio of shear wave velocity and the ratio of density of the substrate to those of the overlayer. The (Sfm)max of the Love mode device can be 20 times higher than that of the shear horizontal SH–surface acoustic wave device fabricated on the same substrate and operating at the same frequency.