COMPARISON OF LUMPED-ELEMENT AND TRANSMISSION-LINE MODELS FOR THICKNESS-SHEAR-MODE QUARTZ RESONATOR SENSORS

Both a transmission-line model and its simpler variant, a lumped-eleme nt model, can be used to predict the responses of a thickness-shear-mo de quartz resonator sensor. Relative deviations in the parameters comp uted by the two models (shifts in resonant frequency and motional resi stance) do not exceed 3% for most practical sensor configurations oper ating at the fundamental resonance. If the ratio of the load surface m echanical impedance to the quartz shear characteristic impedance does not exceed 0.1, the lumped-element model always predicts responses wit hin 1% of those for the transmission-line model.