Wireless implementation of high sensitivity radiofrequency probes for the dielectric characterization of biological tissues

The paper reports on an original wireless inductive radiofrequency probe dedicated to the distant sensing of the dielectric properties of biological tissues, with noninvasive, non-contact, and easy-to-implement diagnosis of tissues in view. The sensing technique lies on the distant monitoring of a high-quality factor radiofrequency resonator electromagnetically coupled to the investigated tissue. The sensing if carried out through the measurement of the modifications of the resonator impedance with the changes of the tissue properties. Firstly, a method dedicated to the wireless measurement of the resonator impedance is proposed and discussed. Secondly, the method is implemented for the sensing of dielectric liquids standing for tissue phantoms. Preliminary sensing results show that the electrical conductivity and the permittivity of the considered phantoms can be distantly and separately sensed. These results open the way to new easy-to-implement tissue characterization techniques.