Dielectric properties of muscle and liver from 500 MHz–40 GHz

Abstract

Dielectric properties are the most important parameters determining energy deposition when biological tissues are exposed to radio frequency and microwave fields. Energy absorption is determined by the specific absorption rate (SAR). SAR distributions can be computed accurately only if the complex relative permittivity of the target tissue is known to a sufficiently high accuracy, and currently there is a lack of data on the dielectric properties of biological tissues at high frequencies. In this study, tissue dielectric properties are measured using an open-ended coaxial probe technique from 500 MHz up to 40 GHz. We present dielectric data for ex vivo bovine and porcine muscle and liver tissues at 37 °C. One-pole Cole–Cole model is used to fit the measured data as a function of frequency and the dispersion parameters are presented. This data is supported by an accurate study on reference liquids such as methanol and ethanediol.

Keywords::

• dielectric properties
• dielectric spectroscopy
• ethanediol
• methanol
• open-ended coaxial probe
• reference materials
• VNA

Acknowledgements

The authors would like to thank Dr Pierre Schembri Wismayer, Department of Anatomy at the Faculty of Medicine, University of Malta for his continuous support throughout this study, and Mr Emmanuel Schembri, Dr Leonardo Cordisco and Dr Mauro Franchina from the Civil Abattoir Malta for their cooperation and for providing the animal tissue samples.

Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.