Modeling material nonlinearities in ultrasonic power transmission through metals

Ultrasonic power transmission (UPT) enables wireless power delivery to sensitive electronics protected in sealed metallic structures, a scenario where conventional electromagnetic transmission fails. The transmission performance of UPT systems is typically sensitive to their operating temperatures, which can fluctuate significantly in practice due to extreme operating environments (e.g., in sealed nuclear waste containers) or the self-heating generated by ultrasonic losses in high-power transmission scenarios. This work introduces an approach for modeling and experimentally characterizing the temperature-dependent performance of UPT systems up to 100 C. Using the finite element method, we develop a high-fidelity model that predicts the system’s efficiency and optimum operating frequency against temperature. The temperature-dependent piezoelectric properties of the transducers used in UPT were first characterized using the impedance method. Next, the model was validated by comparing its predictions to a 1 MHz UPT system under different ambient temperatures. The developed model may accelerate the design of high-power UPT systems through the early identification of the failure modes.