A novel electrode structure compared with interdigitated electrodes as capacitive sensor

Serpentine structure is a novel electrode structure presented in this work. It consists of a combination of meandering and interdigitated electrodes in a single structure with the aim of improving the transduction sensitivity. Capacitors based on this structure, known as serpentine, have been numerically simulated, comparing their capacitance with the interdigitated electrode structure. Simulation results show a bigger capacitance in the serpentine structures than in the interdigitated ones, enhanced for increasing number of fingers. Theoretical calculations agree with results obtained from the experimental characterization of inkjet-printed serpentine and interdigitated structures used as humidity capacitive sensors. We have measured an increase of 28% in humidity sensitivity with capacitors of the same area. Other sensor characteristics such as dynamic response, hysteresis and time drift remained unchanged for both capacitive structures. As this novel serpentine electrode structure presents a bigger geometrical capacitance factor compared to the interdigitated capacitor, in our opinion, it will be a promising base structure for multiple applications in the field of signal transduction.