Preface

The aim of the present book is to explore basic and innovative measurement techniques for the characterization of materials at microwave frequencies, in terms of quantitative determination of their electromagnetic parameters, namely the complex permittivity and permeability. The book is divided into two sections, both including original research contributions. Section 1 is devoted to the illustration of advanced measurement techniques for the characterization of dielectric materials, while Section 2 is focused on the microwave characterization of biological tissues.

Section 1 consists of Chapters 1-6. In Chapter 1 the general theory of open resonators is reviewed by G. Di Massa, and the theoretical treatment of the coupling with a rectangular/circular feeding aperture is provided in terms of fields modal expansion.

In Chapter 2 the theory of microwave open resonators discussed in the companion Chapter 1 is adopted by S. Costanzo et al. for some relevant application contexts, by introducing an equivalent circuit model for the impedance reconstruction of planar surfaces.

A novel reconstruction method is proposed by S. Costanzo et al. in Chapter 3 for the non-invasive microwave characterization of dielectric scatterers. A detailed mathematical description of the proposed approach is first presented, with the details of the relative solving procedure. Experimental results are also reported to discuss the validity of the method for the accurate retrieval of the dielectric permittivity of materials.

In Chapter 4 the design and construction of a simple and inexpensive microwave tomograph for nondestructive testing is presented by R. Monleone et al., with some numerical and experimental reconstruction results concerning the inspection of dielectric materials.

I. Zivkovic and A. Murk present in Chapter 5 an improved procedure and the relative experimental validations for the extraction of complex permittivity and permeability of dielectric and magnetic materials from free-space measurements.

In Chapter 6 A. A. Barba and M. d'Amore discuss the relevance of dielectric properties in microwave assisted processes. An overview of existing characterization techniques

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is first presented, and the application of open-ended coaxial-probe method is then discussed for the extraction of dielectric parameters relevant to food, pharmaceutical ingredients and living materials.

Section 2 consists of Chapters 7-8. In Chapter 7 O. Zeni and M. R. Scarfì describe the main requirements for a well conducted in vitro study to evaluate the biological effects of radiofrequency radiation.

In Chapter 8 M. Ibrani et al. illustrate the main existing theoretical studies on the agedependence of permittivity and conductivity of human biological tissues at microwave frequencies.

I wish to thank all book contributors for the original submitted results coming from their research activities. A special acknowledgement is due to the Editorial Assistants for their professional support during the book preparation.

> **Sandra Costanzo** University of Calabria Italy

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ingredients and living materials.

of radiofrequency radiation.

frequencies.

is first presented, and the application of open-ended coaxial-probe method is then discussed for the extraction of dielectric parameters relevant to food, pharmaceutical

Section 2 consists of Chapters 7-8. In Chapter 7 O. Zeni and M. R. Scarfì describe the main requirements for a well conducted in vitro study to evaluate the biological effects

In Chapter 8 M. Ibrani et al. illustrate the main existing theoretical studies on the agedependence of permittivity and conductivity of human biological tissues at microwave

I wish to thank all book contributors for the original submitted results coming from their research activities. A special acknowledgement is due to the Editorial Assistants

> **Sandra Costanzo** University of Calabria

> > Italy

for their professional support during the book preparation.

**Advanced Techniques for Microwave Dielectric Characterization** 
