Multifrequency RF sensor for the non-contact monitoring of tissues

The dielectric properties of organic tissues are related to their biological composition and structure. Monitoring those properties in a non-invasive and non-contact way is still a major challenge in biomedical applications. This paper presents a multifrequency inductive sensor based on an original combination of several passive radiofrequency inductive resonators, called WMFR. To assess the ability of the WMFR to monitor the dielectric properties of tissues, the decomposition of a beef muscle tissue sample was sensed during 6 days. The dielectric properties of the tissue were estimated during decomposition, and the WMFR was found able to sense the changes over time at 7 different frequencies ranging in the 20-350 MHz bandwidth. This study opens the way to a new generation of non-contact and wearable sensors dedicated to dielectric monitoring applications in the biomedical field.