Three-Port Lorentz Resonance Based Permittivity Sensor and Microwave Comparator

This paper presents for the first time a compact three-port Lorentz resonance-based microstrip sensor for permittivity and moisture sensing, as well as refractive index comparison. The proposed sensor is verified by simulations and experiments. The resonant frequency of the designed sensor is 2.24 GHz. The proposed sensor has a quality factor of 102, sensitivity of 45.4 mm/refractive index unit, and figure-of-merit of 34.6. The sensitivity of the proposed sensor is quite superior to other resonance based sensors and a fair comparison is presented in this work. The proposed sensor can be used to find the permittivity of dielectric materials, the moisture content of plants, as well as can be used as a refractive index comparator.