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ANALYTIC MODELS FOR ACOUSTIC WAVE PROPAGATION IN AIR
JoAnna Ruth Vetreno
Date: 2007-12-04
Degree: MS - Electrical Engineering
Advisory Committee
Dr. Hamid Krim - Committee MemberDr. Kevin Gard - Committee Member
Dr. Michael B. Steer - Committee Chair
Abstract
Ultrasound waves have been used for imaging purposes for many years. However, a liquid interface has always been necessary between the transducer and the object being imaged due to a high mechanical resistance at the air-transducer interface. Recent advances in transducers have made it possible to omit the liquid interface, allowing imaging to be done through air interfaces. Because this is a relatively new field, research into ultrasound propagation in air is very limited. A comprehensive model of how an ultrasound wave propagates through air would expedite the study of air-coupled ultrasound for imaging. This thesis presents a mathematical model of two-dimensional linear acoustic wave propagation in air. The model takes as input the frequency and amplitude of an acoustic signal and outputs the pressure field over varying longitudinal and lateral distances from the source. The benefits of a mathematical model over a finite element model are first discussed, then the mathematical model for acoustic propagation in air is developed using both computer simulations and physical experiments in an anechoic chamber. Results are presented and compared to experimental data to confirm the validity of the mathematical model.
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