Marco Bini

The Polyacrylamide as a Phantom Material for Electromagnetic Hyperthermia Studies

The Polyacrylamide gel is suggested as a new and convenient material for simulating the electrical behavior of biological tissues in experimental studies of heat deposition by electromagnetic means. The advantages of Polyacrylamide are: 1) excellent optical transparency, 2) solid elastic, 3) easily shaped into complex forms, 4) readily prepared with a complete range of highly reproducible values of electrical parameters, which can also be combined to simulate various different tissues in complex structures. The material is also low-cost and readily available.

Use of polyacrylamide as a tissue-equivalent material in the microwave range

The use of polyacrylamide gel to simulate biological tissues at microwave frequencies is presented. Formulation and preparation procedures are discussed. Measurements of complex permittivity in the range from 0.75 to 5.5 GHz, together with its temperature sensitivity, are reported. Thermal and optical properties have also been measured: the polyacrylamide is transparent and may be used as a phantom material in designing and testing applicators for microwave hyperthermia and for dosimetry studies.<<ETX>>

Non-destructive permittivity measurement of solid materials

An open-coaxial probe suitable for measuring the permittivity of solid materials has been designed and tested. The peculiar structure of the probe allows an easy and firm contact with the surface of the material under measurement, resulting in highly reliable and reproducible dielectric measurements. The permittivity measurement is absolute, as the calibration procedure - based on a genetic algorithm - does not require the use of dielectric standards. The measurement system - including the probe, a network analyser, and the numerical code to determine the permittivity from reflection measurements - have been tested on solid materials of known properties, and used for determining the dielectric characteristics of several types of wood.

High permittivity patch radiator for single and multi-element hyperthermia applicators

A compact, low-profile patch radiator which is the base element for efficient, small-size applicators suitable for superficial hyperthermia is described. The design criteria and the technological processes involved are presented. The electromagnetic characteristics of the patch element are outlined, and possible application of the radiator are discussed.<<ETX>>

Microwave heating for the rapid determination of thermodynamic functions of chemical reactions

A new technique, based on microwave heating, is proposed for the determination of thermodynamic functions of chemical reactions. The reliability of the method has been varified by studying two typical chemical equilibria (complex-formation and acid–base) as well as the temperature behaviour of several polar solvents. The absence of temperature gradients inside the sample, the broad range of variability of the slope of the temperature rise, the very short response time and the applicability to various common polar solvents other than water, qualify the method for various other applications in thermochemistry.

A Measurement System For Investigating The Dielectric Properties Of Low-Loss Polymers

Abstract Polymers with low dielectric losses are largely used in several electromagnetic applications, for example in telecommunications cables, antennas, and microwave devices and components. The interest in studying their dielectric properties has a twofold motivation: (1) a scientific motivation, because the study of polymers is one of the main fields of material science; and (2) an industrial one, because a material with better dielectric characteristics—i.e. lower dielectric losses—is commercially more suitable for the market. The measurement of both dielectric constant and losses is not a straightforward task when dealing with low-loss materials. In this paper we describe a measurement system, based on a revisitation of the well known method of re-entrant cavity, which by a thorough electrical modeling of the sample holder allows absolute measurements to be performed on dielectrics with loss tangent as low as 10−4. The technique is validated on low-loss substrate materials of known characteristics. Measurement examples are reported concerning two fluorinated polymers based on TFE and ECTFE.