PORTEFEUILLE

Meta-materials are periodic structures, like large-scale artificial crystals built in metal or plastic. They have very special characteristics in the microwave domain, like negative refraction index, which allows under certain conditions, building “superlenses” free of some of the constraints of classical electromagnetics. In the optical domain, they are responsible for the shiny colors of some butterflies and other insects.

Hyperthermia is a cancer treatment method which is based on heating of the cancerous tissue at 43°C, using a high-frequency electromagnetic field applied to the body. It is based on the fact the tumor are more sensitive to heating than healthy tissue.

The issue yet to be solved with microwave hyperthermia is directing precisely the electromagnetic field only on the tumor cells, to make the treatment more efficient.

Reasonable results have been obtained using “classical” antennas, with expensive commercial machines, and a potentially low-cost solution demonstrated at the IICT. But the applicators developed industrially and at IICT also show limitations, due to fundamental limits of the classical antenna theory. Metamaterials, show great potential to break these limitations, in particular by better shaping of the electromagnetic field, in particular focusing, or on the opposite spreading of the electromagnetic field which will heat the tissues.

This project proposes to explore the design and fabrication of metamaterial antennas applied to hyperthermia and other medical applications. 3D printing is a promising way to produce these complicated structures which look like macro-models of crystals.

The scientific field of meta-materials is still quite new, but ready for applications: the challenge is now to develop engineering methods for the design and fabrication of these structures. This will allow advances in the field of satellite communications and radar, as well as improving sensors.

To go from fundamental science to demonstrators, and then to very practical applications benefiting cancer patients in rich and poor countries, but also other applications in health, as well as communication technologies.

3D printed materials samples from several different polymers and different manufacturers have been produced, and their RF properties are currently measured. This is important to identify the materials that are most suitable for microwave: with the highest permittivity and lowest loss.

Several antenna structures have been printed, and the tweaking of the machine for the best printing results is in progress. It is important to get the cleanest printing.
Lastly, solutions to produce 3D-printable materials with high permittivity have been researched, which involves mixing high permittivity ceramic powders with polymers and re-extruding printer “plastic wire” from this mix. However, the practical implementation is difficult.

We have applied meta-materials to several of our projects involving antennas, especially in satellite and radar. However, this has shown that there their application is sometimes difficult, especially for a relatively large frequency range.