Investigation of the 3-Overtone Quality Factor of Quartz Crystal Resonator with Ring Electrodes

Currently, the quartz crystal microbalance (QCM) sensor with ring electrodes operating in third overtone mode is developed rapidly during to its uniform sensitivity distribution. The 3-overtone quality (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>) factor determines the stability of quartz crystal resonator (QCR) with ring electrodes operating in third overtone mode. However, there are few research works to investigate the Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> of the QCR with ring electrodes. Herein, we studied the Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> of the QCR with ring electrodes working in the third overtone mode. The experimental results show that all the Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> values are larger than 120000 and strongly prove that all QCRs with ring electrodes operating in the third overtone mode are reliable. On the other hand, we clarified the difference between the actual 3-overtone quality factor (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>) and the nominal 3-overtone quality factor $\left( {Q_3^{\prime}} \right)$ of the QCR with ring electrodes, and pointed out that the researcher always misunderstands about the nominal $Q_3^{\prime}$ and the actual Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>. Finally, the actual Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> is 5.7~9.3 times that of the nominal $Q_3^{\prime}$. These findings will promote the reliable use of QCRs with ring electrodes operating in the third overtone mode in the sensing and measuring fields.