Accurate Prediction of Measured Microwave-Induced Thermoacoustic Signals via Multiphysics Simulations Augmented With an Acoustic Detection System Transfer Function

Abstract

Multiphysics simulation tools for modeling the generation and propagation of microwave-induced thermoacoustic (TA) signals aid in the development of emerging applications in medical imaging and communications. Simulation models of microwave-induced TA signals that lack consideration of the impact of the acoustic detection system result in a mismatch in the temporal characteristics of simulated and measured TA signals. We address this discrepancy by introducing an acoustic detection system transfer function that captures the combined effects of the ultrasound transducer and the acoustic signal filtering/amplification system and can be applied to simulated signals to improve their predictive accuracy. We determine the transfer function of a microwave-induced TA signal measurement system by comparing simulated and measured TA signals in a training testbed. We apply this transfer function to a set of simulated TA signals obtained from a performance evaluation testbed (differing from the training testbed) and compare to measured TA signals from that same testing scenario. We show that this technique resolves a long-standing discrepancy between simulation and experiment. Our proposed methodology for determining the acoustic detection system transfer function can be extended to other acoustic detection applications that require high-fidelity simulation models.