Dual Range and High Data-Rate Intrabody Communication Transceiver based on Piezoelectric Micromachined Ultrasonic Transducers

Abstract

In this paper, we demonstrate the implementation of a dual range (short d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</sub> =3.5cm and long d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> =13.5cm distance application) and high bandwidth, high data-rate transceiver ( BW ≈ 200kHz and Data-Rate ≈ 400kbits/s) for intrabody communication links based on Piezoelectric Micromachined Ultrasonic Transducers (pMUTs). The transceiver consists of a Quadrature Phase-Shift Keying (QPSK) modulation and demodulation scheme implemented in a Universal Software Defined Radio (USRP). The intrabody antennas consist of a 10×10 uni-morph pMUT array based on Aluminum Nitride (AlN) with circular shape design and resonance frequency f ≈ 700kHz. The arrays are embedded in a tissue phantom to mimic human tissue properties and are coupled with ultrasound gel to avoid air gaps. The system was tested by serializing a 100×50pixels image in a bit stream and transmitting over the intrabody link. The sampling rate was set at twice the bandwidth of the pMUTs based on the Nyquist theorem. The detected Bit Error Rate (BER) was 1E-4 and 1E-1 for short and long range respectively, demonstrating the functionality of the pMUT intrabody transceiver. These levels of BER allow for perfect reconstruction of the original data by time-averaging successive frames.