Implementation of QCM with Uniform Mass Sensitivity Distribution

Quartz crystal microbalance (QCM) has been widely used in various fields due to its high sensitivity, low system complexity, and the ability to output online in real time. However, characteristic of the Gaussian mass sensitivity distribution brings large error and limits QCM further use in practical applications and commercialization. Through theoretical calculation, it is found that the ring electrode QCM can obtain an approximately mass sensitivity distribution by carefully selecting the inner, outer diameters and electrode mass loading factor. A plating experiment was performed to verify the uniform mass sensitivity distribution of 10 MHz ring electrode QCMs with inner and outer diameters of 2 mm and 5 mm, and the experimental results are consistent with the theoretical analysis results. Due to the effects of material density and other factors, the electrode mass loading factor of the gold QCMs for achieving a uniform mass sensitivity distribution is different that of silver QCMs. The special designed QCMs are low-cost and conducive to improving the repeatability.