International Journal of Power Electronics and Drive System (IJPEDS) Vol. 10, No. 2, June 2019, pp. 1064~1071 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v10.i2.pp1064-1071  1064 Journal homepage: http://iaescore.com/journals/index.php/IJPEDS Study and simulation with VHDL-AMS of the electrical impedance of a piezoelectric ultrasonic transducer Toufik Merdjana, Abdelhafid Chaabi Hyper Frequency and Semiconductor Laboratory (LHS), University Mentouri Constantine1, Algeria Article Info ABSTRACT Article history: Received Sep 22, 2018 Revised Nov 19, 2018 Accepted Mar 3, 2019 Ultrasonic transducers are a key element that governs the performances of both generating and receiving ultrasound in an ultrasonic measurement system. Electrical impedance is a parameter sensitive to the environment of the transducer; it contains information about the transducer but also on the medium in which it is immersed. Several practical applications exploit this property. For this study, the model is implemented with the VHDL-AMS behavioral language. The simulations approaches presented in this work are based on the electrical Redwood model and its parameters are deduced from the transducer electroacoustic characteristics. Keywords: Impedance Piezoelectic Transducer Ultrasonic VHDL-AMS Copyright © 2019 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: Toufik Merdjana, Department of Electronic, Faculty of science and Technology, University Mentouri Constantine1, Algeria Constantine, Algeria Email: merdjana_toufik@umc.edu.dz 1. INTRODUCTION Ultrasound systems are widely used. They find many applications in engineering, medicine, biology, and other areas. The one indispensible part in these systems is the transducer. These will use the properties of magnetostrictive or piezoelectric materials to convert electrical energy into ultrasonic mechanical energy [1]. Piezoelectric materials have the advantage over other systems of having good performance and being available in very diverse geometries. The electromechanical interaction of piezoelectric transducer, represented by electrical equivalent circuits, was first introduced by Mason [2]. He proposed an exact equivalent circuit that separated the piezoelectric material into an electrical port and two acoustical ports through the use of an ideal electromechanical transformer. The problems with the model are that it required a negative capacitance at the electrical port. Redwood [3] improved this electromechanical model by incorporating a transmission line, making possible to extract useful information on the temporal response of the piezoelectric component. The Electrical impedance is a parameter sensitive to the environment of the transducer. Several practical applications exploit this property[4, 5]. The measurement of the impedance makes it possible, for example, to detect the physical or structural modifications of the medium due in particular to damage. This approach is used for non-destructive testing to monitor the condition of structures such as aging and corrosion [6, 7]. Frequency analysis of the impedance makes it possible to precisely locate the resonance zone of the transducer. This location can be exploited to control and stabilize the operating frequency of high power systems such as ultrasonic welding devices [8]. Real-time knowledge of the electrical impedance also makes it possible to determine and optimize the power emitted by a transmitter or the sensitivity in reception of a piezoelectric sensor [9].