The non-invasive characterization of organic matter is a major issue in many fields of activity, such as agriculture, food industry and health. The complex permittivity being a relevant indicator of the physiological state of organic matter, especially in the 10s to 100s of MHz, we have developed a non-contact RF multi-frequency resonant sensor, able to monitor the dielectric properties of the targeted organic media in non-invasive way. This wireless multifrequency resonator (WMFR) sensor basically consists in a set of high sensitivity circular transmission-line LC resonators, arranged in a staggered and monolithic configuration, and deposited on the same low loss substrate. Controlled by the means of a distant and monitoring RF probe by inductive coupling, the WMFR sensor operates as a multi-resonant transmit and receive antenna, able to distantly monitor the dielectric changes occurring in the targeted organic material, with both various investigation frequencies and various penetration depths within the matter. In the framework of the LaSIPS project (ANR-10-LABX-0040-LaSIPS) managed by the French National Research Agency, and in the context of the Ph.D Works of Alexiane Pasquier (Defended January 26th, 2022) we have proposed a proof of concept of the WMFR sensor with our colleagues from SATIE – CYU (Cergy Paris University). A 8-Frequency WMFR demonstrator of 9 cm outer diameter, featuring 8 concentric single-turn LC-resonators was developed to operate in the 22 MHz to 340 MHz bandwidth. It was fabricated on a flexible substrate (Kapton) and an electrical equivalent modeling was proposed. The ability of the sensor to distantly monitor the complex permittivity of biomimetic solutions have been successfully demonstrated within the 0 to 5 S/m conductivity range and the 20 to 80 permittivity range, together with the ability of detecting local dielectric contrasts within a uniform dielectric media, mimicking a tissue anomaly such as a tumor or lesion in a tissue. Monitoring of fruit ripening over a 14-day period and monitoring of muscle tissue alteration over 6 days were also performed, validating the ability of WMFR to detect changes in actual organic matter in a non-contact, non-invasive manner with prospects for low cost and online implementations. A patent application was filed by Université Paris Saclay for the WMFR principle in November 2021, and another patent application was filed for the implementation of WMFR arrays in January 2022. Prospective applications in the field of agri-food industry is the smart packaging of foods, and health-related prospects are the development of non-invasive device such as breast cancer or skin-wound healing wearable monitoring devices.
References
A. Pasquier, Ph.D Thesis : Towards non-contact characterization of organic tissue changes by multi-frequency RF sensors, Université Paris Saclay, Defended January 26th, 2023 (https://www.theses.fr/261169211).
A. Pasquier, Y. Le Diraison, S. Serfaty, P-Y. Joubert, Device of multifrequency electromagnetic resonators inductively coupled together forming a resonator network or a meta-material, and method of implementation. Patent Application FR2200687 (January 26th, 2022).
A. Pasquier, Y. Le Diraison, S. Serfaty, P-Y. Joubert, "Device and method for electromagnetic characterization of a medium by resonator, without contact, object and associated resonator" Patent Application FR2112292 (November 19th, 2021).
A. Pasquier, Y. Le Diraison, S. Serfaty, P-Y. Joubert « Non-contact inductive radiofrequency monitoring of a beef muscle tissue decomposition », 17th edition of IEEE International Symposium on Medical Measurements and Applications, Messina, Italy, June 22-24, 2022. (DOI: 10.1109/MeMeA54994.2022.9856543)
Non-contact fruit ripening monitoring using a radiofrequency passive resonator
S. Castanet, A. Pasquier, H. Boukharouba, T.H.N. Dinh, S. Serfaty, P.-Y. Joubert, Sensors and Actuators A : Physical, Volume 347, 2022, 113902,
DOI : doi.org/10.1016/j.sna.2022.113902
Contcat C2N : Pierre-Yves Joubert
