Pulsed EM fields in biological tissue

For optimizing medical applications, it is important to understand how, and to what extent, the electromagnetic field propagates inside a living-tissue configuration. Therefore, the electromagnetic field excited by a current pulse in a circular loop has been calculated for a model of plane-stratified biological tissues. To incorporate the effects of dispersion in the configuration, permittivity models for skin, fat and bone tissue have been developed. Using a curve-fitting procedure, 6-term Dobya dispersion models have been determined. A model for muscle tissue was already available from the literature. The results indicate that tissue dispersion yields a broadening of the pulse shape and that high-frequency components in the pulse spectrum attenuate more that low-frequency components. Furthermore, stratification causes partial reflection which results in fluctuations of the time-dependent electromagnetic field.