Shang Wenling, Wang Danrui, Miao Bin, Yao Shutao, Ta Guifeng, Liu Haojie, Tao Jinyan, Liu Xiaonan, Zhao Xiangyong, Li Jiadong
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China.
Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
Micromachines (Basel). 2025 Jan 26;16(2):145. doi: 10.3390/mi16020145.
Due to their compact sizes, low power consumption levels, and convenient integration capabilities, piezoelectric micromachined ultrasonic transducers (PMUTs) have gained significant attention for enabling environmental sensing functionalities. However, the frequency inconsistency of the PMUT arrays often leads to directional errors with the ultrasonic beams. Herein, we propose a reconfigurable PMUT array based on a ScAlN piezoelectric thin film for in-air ranging. Each element of the reconfigurable PMUT array possesses the ability to be independently replaced, enabling matching of the required frequency characteristics, which enhances the reusability of the device. The experimental results show that the frequency uniformity of the 2 × 2 PMUT array reaches 0.38% and the half-power beam width (θ) of the array measured at 20 cm is 60°. At a resonance of 69.7 kHz, the sound pressure output reaches 7.4 Pa (sound pressure level of 108.2 dB) at 19 mm, with a reception sensitivity of approximately 11.6 mV/Pa. Ultimately, the maximum sensing distance of the array is 7.9 m, and it extends to 14.1 m with a horn, with a signal-to-noise ratio (SNR) of 19.5 dB. This research significantly expands the ranging capability of PMUTs and showcases their great potential in environmental perception applications.
由于其尺寸紧凑、功耗低以及集成方便的特性，压电微机械超声换能器（PMUT）在实现环境传感功能方面受到了广泛关注。然而，PMUT阵列的频率不一致性常常导致超声束出现方向误差。在此，我们提出一种基于ScAlN压电薄膜的可重构PMUT阵列用于空气中测距。可重构PMUT阵列的每个元件都具备独立更换的能力，能够匹配所需的频率特性，从而提高了器件的可重复使用性。实验结果表明，2×2 PMUT阵列的频率均匀性达到0.38%，在20 cm处测量的阵列半功率波束宽度（θ）为60°。在69.7 kHz的共振频率下，在19 mm处声压输出达到7.4 Pa（声压级为108.2 dB），接收灵敏度约为11.6 mV/Pa。最终，该阵列的最大传感距离为7.9 m，使用喇叭时可扩展到14.1 m，信噪比（SNR）为19.5 dB。这项研究显著扩展了PMUT的测距能力，并展示了它们在环境感知应用中的巨大潜力。
