A novel dielectric constant detection method using a microstrip sensor is presented in this paper. The aim was to estimate the dielectric constant in the space above a resonator which was the basic part of the sensor. Variation in resonant frequency of the resonator was considered as the criterion for detection of the dielectric constant variation. The microstrip resonator was designed using coupled stepped impedance open stubs. The circuit model of the resonator was then extracted and the resonant frequency as a function of the dielectric constant was obtained. Applicability of the proposed method was verified in experimental studies.
