Implantable Galvanic-Coupled Body Channel Communication Transceiver with Serpentine-Interconnection Electrode Pair for Post-Operative Monitoring of Joint Replacement

This paper presents a galvanic-coupled body channel communication (GC-BCC) transceiver (TRX) system with serpentine-interconnection electrodes for applications in joint replacement surgeries, such as total knee replacement (TKR). The proposed system consists of a GC-BCC transmitter (TX) implanted inside the body and an external receiver (RX). Implanted devices with high stiffness may cause tissue damage or compromise long-term stability due to the inherent curvature and elasticity of the human body. Given these characteristics of the human body, implantable devices should feature flexible and stretchable structures that conform to the body’s contours and minimize such risks. To address this requirement, we propose a serpentine-interconnection electrode pair, which provides mechanical compliance and can replace the conventional straight-interconnection interface. This interconnection enables reliable signal transmission in the MHz band, demonstrating its suitability for both implantable TX and external RX in medical applications. The GC-BCC TX and RX are fabricated using 0.18 µm BCD and 0.18 µm CMOS processes, respectively, achieving a data rate of 20 Mb/s with a bit error rate (BER) of less than 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup>. The TX and RX chips consume an active area of 3.2 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 2.5 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consume a power of 675 µW and 4.32 mW, respectively. The performance of the proposed system is validated through ex-vivo experiments using 10-mm thick porcine tissue.