Flexible printed electrically small microwave resonator for automated displacement tracking

In this paper, a planar split ring resonator-based flexible RF sensor is developed for linear and rotational position tracking of a target object. The proposed sensing scheme employs a 100 μm thin flexible printed resonator that facilitates ease of adherence to a target object than that of the conventional RF sensor. The realized printed resonator is excited by a near-field proximity coupling mechanism using a standard 50 Ω microstrip line. A detailed numerical analysis for the linear and rotational displacement of several dummy targets is carried out by recording the change in measured parameters corresponding to the relative change in position of the printed resonator attached to a dummy target under test. Afterward, the equivalent circuit and fabricated prototype of a printed flexible sensor is developed and tested for the linear and rotational displacement of several target materials under observation and an ANN model is developed to curb the uncertainty.