PMUT-based high data rate ultrasonic wireless communication link for intra-body networks

Abstract

This paper reports on the first demonstration of a high data rate (0.6 Mbit/s) ultrasonic wireless communication link implemented through Aluminum Nitride (AlN) Piezoelectric Micro Machined Ultrasonic Transducers (PMUTs). Real-time video streaming is demonstrated through a phantom mimicking human tissue, thus proving the feasibility of PMUT-based implantable Body Area Networks (BANs). Two 20 × 20 PMUT arrays were used as transceiver elements and an Orthogonal-Frequency-Division-Multiplexing (OFDM) modulation scheme was implemented resulting in a wideband digital transmission link with a data rate of up to 0.6 Mbit/s at a 5 cm distance between transmitter and receiver. Channel estimation and Bit-Error-Rate (BER) versus Signal-to-Noise-Ratio (SNR) curves were obtained for both the PMUT link and an implementation based on custom-made and miniaturized ultrasonic bulk Lead Zirconate Titanate (PZT) transducers for comparison. The PMUT implementation, characterized by a wider bandwidth than the PZT transducers, showed two orders of magnitude lower BER for the same SNR as compared to its PZT counterpart, while occupying an approximately 100 times smaller volume (∼3mm×3mm×0.5mm PMUT array vs. 9.5 mm diameter, 6 mm thick PZT transducer).