Ultrasonic transcutaneous energy transfer using a continuous wave 650 kHz Gaussian shaded transmitter

This paper proposes ultrasonic transcutaneous energy transfer (UTET) based on a kerfless transmitter with Gaussian radial distribution of its radiating surface velocity. UTET presents an attractive alternative to electromagnetic TET, where a low power transfer density of less than 94 mW/cm(2) is sufficient. The UTET is operated with a continuous wave at 650 kHz and is intended to power devices implanted up to 50mm deep. The transmitter was fabricated using a 15 mm diameter disc shape PZT (Lead Zirconate Titanate) element (C-2 grade, Fujiceramics Corporation Tokyo Japan), in which one surface electrode was partitioned into six equal area electrodes ( approximately 23 mm(2) each) in the shape of six concentric elements. The UTET was experimented using pig muscle tissue, and showed a peak power transfer efficiency of 39.1% at a power level of 100 mW. An efficient (91.8%) power driver for the excitation of the transmitter array, and an efficient rectifier (89%) for the implanted transducer are suggested. To obtain the pressure field shape, the Rayleigh integral has been solved numerically and the results were compared to finite element simulation results. Pressure and power transfer measurements within a test tank further confirm the effectiveness of the proposed UTET.