Design and investigation of a Remote Interrogation System for capacitive measurement, exploiting Inkjet Printed techniques

Remote Interrogation Systems (RIS) are mostly used to collect data from devices operating in hostile or harsh environments, where cabled connections and/or the use of batteries are not allowed or strongly not recommended. This is particularly relevant in the case of sensing systems adopted for the sake of control or monitoring. Among different techniques, LC resonator-based approaches show interesting features. This paper deals with the optimal design, the realization and the characterization of a hybrid coupled-coil RIS for the measurement of capacitive devices, based on the Time-Gated strategy. A proof-of-concept prototype has been developed by using two planar coils realized by Printed Circuit Board and Inkjet Printing technologies, respectively. Obtained results highlight the suitability of the proposed design methodology, as well as the considered realization technologies. In particular, a system responsivity of 23.73 kHz/pF has been obtained, while its accuracy and resolution have been estimated as 1.35 pF and 1.15 pF respectively.