Displacement sensor based on interdigital capacitor

In this paper we investigate the possibility of displacement detection by approaching dielectric plate to electrodes of interdigital capacitor. Working principle of this sensor is based on penetration depth of the fringing electric fields above capacitors electrodes and its intersection with dielectric plate. Tests were done with interdigital capacitor and dielectric plates fabricated in Low Temperature Co-fired Ceramic (LTCC) technology. Experimentally obtained results are compared with a theoretical model. Good agreement between measured results and parameters estimated by analytical calculations are obtained.