Wireless Power and Data Transfer over Inductive Links for Biomedical Applications: Recent Advances, Challenges, and Limitations.

Wireless power transfer (WPT) has emerged as a promising technology for modern implantable medical devices (IMDs), providing a reliable alternative to traditional batteries and reducing the need for repeat surgical procedures. WPT-based IMDs are extensively employed in biomedical applications such as deep brain stimulators, endoscopic capsules, pacemakers, and cardiac monitoring systems, which are being commercialized. As the IMD market is expected to grow with the aging population, extensive research efforts are proceeding to address key design and implementation challenges. A key challenge lies in simultaneously achieving high power-transfer efficiency (PTE), high data rates, low power consumption, and low circuit complexity. This review paper thoroughly examines recent developments, design trends, and current research problems in simultaneous power and bidirectional data transmission over a single inductive link, as well as the associated modulation and demodulation techniques. We reviewed various uplink and downlink modulation techniques, focusing on key characteristics such as data rate, power consumption, circuit complexity, and health and safety considerations. Finally, future research directions toward efficient, compact, and reliable simultaneous wireless power and data transfer (SWPDT) for the next generation of IMDs are discussed. This review paper will hopefully guide ongoing research into more efficient, scalable, and safe SWPDT systems.