Modelling and simulation of ultrasound non linearities measurement for biological mediums

Abstract

We present an implementation of the nonlinear propagation in an ultrasonic measurement modelling with VHDL-AMS–IEEE-1046-1999 language. The system is dedicated to nonlinear mediums characterization by a compared method measurement. Usual modelling of ultrasonic transducers are based on electrical analogy and are not simulated in the global measurement environment. The ultrasonic transducer modelling proposed is simulated with the nonlinear acoustic load and electronic excitation. The nonlinear B/A parameter is used to characterize medium with a comparative method. The measurement cell is composed of two piezoelectric ceramic transducers which are implemented with the Redwood’s electric scheme. The analyzed medium is placed between the transducers and modeled to take into account the nonlinear propagation with the B/A parameter. The usual transmission line model has been modified to take into account the nonlinear propagation for a one dimensional wave. Results obtained with simulation of mediums characterization with (blood, milk, liver and human fat tissue) showed good a modeling in agreement between modelling and experimental measurement, also a maximum error of about 12.5%.