Microwave Planar Sensors for Fully Characterizing Magneto-Dielectric Materials

This paper presents two complementary split-ring resonator (CSRR)-based sensors for full characterization of magneto-dielectric materials. The first proposed sensor is designed by loading the microstrip line with a CSRR, while the second one is by loading the microstrip line with two CSRRs. To distinguish the effects of permittivity and permeability on the shift of resonant frequency, the electric and magnetic fields are designed to be located at two separate zones in the CSRR. Two 50Ω resistors are mounted at the ends of the microstrip line to increase the quality factor. In addition, the second sensor can perform measurements of complex permittivity and complex permeability of the magneto-dielectric materials in a single run, thereby making the measurement faster, easier, and in a more cost-effective way. The prototypes of two proposed sensors are fabricated and tested for validation of their functionality. A good agreement can be achieved between the measured data and the reference values from the manufacturers' datasheet, thereby demonstrating the applicability of the proposed sensors for full characterization of the magneto-dielectric materials.