It is a longstanding issue that high-order width-extensional (WE) piezoelectric microelectromechanical system (MEMS) resonators suffer low quality factors (Q-factors). In this study, it is observed that the mode distortion occurs in each unit when it couples with each other to constitute the high-order WE-mode resonator, leading to a decreased Q-factor. Based on this finding, we propose a new Q-factor boost strategy by improving mode matching degree between adjacent units from the view of dividing the high-order resonator into units. Both simulation and experimental results show a significant improvement in mode matching degree between adjacent units with varied unit length. Resonator’s Q-factor measured in air improved by 53% compared with the conventional resonator with constant unit length. It is believed that the proposed strategy could apply to other WE-mode MEMS resonators with different orders or dimensions; and Q-factor can be further improved by combining the proposed method with traditional energy reflection methods. [2023-0201]

中文翻译：

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不同单位长度高阶宽度扩展模式 MEMS 谐振器的 Q 因子提升策略

高阶宽度扩展 (WE) 压电微机电系统 (MEMS) 谐振器的品质因数 (Q 因数) 较低是一个长期存在的问题。在这项研究中，观察到当每个单元相互耦合构成高阶 WE 模式谐振器时，每个单元都会发生模式失真，导致 Q 因子下降。基于这一发现，我们从将高阶谐振器划分为单元的角度出发，提出了一种新的Q因子提升策略，通过提高相邻单元之间的模式匹配程度。仿真和实验结果均表明，不同单元长度的相邻单元之间的模态匹配度显着提高。与具有恒定单位长度的传统谐振器相比，在空气中测量的谐振器的品质因数提高了 53%。据信，所提出的策略可以适用于其他不同阶数或尺寸的WE模式MEMS谐振器；通过将所提出的方法与传统的能量反射方法相结合，可以进一步提高Q因子。 [2023-0201]