Ultrasonic transcutaneous energy transfer for powering implanted devices

• Published in: Ultrasonics Vol. 50; no. 6; pp. 556 - 566
• Main Authors: Ozeri, Shaul, Shmilovitz, Doron
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2010; Elsevier
• Subjects: Acoustic impedance matching; Acoustic Impedance Tests; Acoustics; Activation; Biological and medical sciences; Devices; Electric Power Supplies; Electronics; Energy transfer; Energy Transfer - physiology; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Matching; Medical sciences; Models, Theoretical; Physics; Power transfer; Powering implanted devices; Prostheses and Implants; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Skin Physiological Phenomena; Technology. Biomaterials. Equipments. Material. Instrumentation; Transcutaneous energy transfer; Transducers; Transduction; acoustical devices for the generation and reproduction of sound; Ultrasonic energy; Ultrasonics; Ultrasonics, quantum acoustics, and physical effects of sound; Powering implanted devices; Acoustic impedance matching; Transcutaneous energy transfer; Ultrasonic energy; Human; Transdermal system; Prosthesis; PZT; Experimental study; Modeling; Piezoelectric ceramics; Optimization; Acoustic impedance; Finite element method; Tissue; Continuous wave; Impedance matching; Thick film; Graphite; Power device; Ultrasonic transducer; Energy transfer
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2009.11.004

This paper investigates ultrasonic transcutaneous energy transfer (UTET) as a method for energizing implanted devices at power level up to a few 100 mW. We propose a continuous wave 673 kHz single frequency operation to power devices implanted up to 40 mm deep subcutaneously. The proposed UTET demonstrated an overall peak power transfer efficiency of 27% at 70 mW output power (rectified DC power at the load). The transducers consisted of PZT plane discs of 15 mm diameter and 1.3 mm thick acoustic matching layer made of graphite. The power rectifier on the implant side attained 88.5% power transfer efficiency. The proposed approach is analyzed in detail, with design considerations provided to address issues such as recommended operating frequency range, acoustic link matching, receiver’s rectifying electronics, and tissue bio-safety concerns. Global optimization and design considerations for maximum power transfer are presented and verified by means of finite element simulations and experimental results.