Multichannel PMUT for Wireless Power Transfer and Data Telemetry

This article introduces a piezoelectric micromachined ultrasonic transducer (PMUT) capable of simultaneous acoustic power transfer and multichannel data telemetry. Using a custom electrode design based on unique mode shapes, the dual functionality is demonstrated in both circular and square prototype PMUTs. These devices were evaluated for their ability to concurrently perform wireless power transfer (WPT) and data telemetry, emphasizing the simultaneous transmission of carrier signals tied to specific device modes. The electrode configurations of these prototypes, reflecting the distinct mode shapes, have been carefully engineered to heighten sensitivity across multiple modes, ensuring balanced channel signal intensity during multichannel operation. In an ambient setting, the circular PMUTs demonstrated an output power transfer of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.52~\mu $ </tex-math></inline-formula>W and a data rate of 200 kb/s with a separation of 1.5 cm. Emphasizing their utility in a biomedical context, the circular PMUTs, when tested within a tissue-mimicking phantom, yielded a power output of 411.3 nW, a data rate of 50 kb/s, and a bit error rate (BER) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7\times 10^{-{2}}$ </tex-math></inline-formula>. In comparison, the square PMUTs recorded a power output of 202.4 nW, a data rate of 10 kb/s, and a BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.1\times 10^{-{4}}$ </tex-math></inline-formula>. Collectively, these results illuminate the multichannel capabilities of PMUTs for simultaneous dual function operation.