A microwave sensor for measuring multi-frequency full characteristics of magneto-dielectric materials

摘要

In this paper, a microwave sensor based on a complementary split resonance ring structure is proposed to measure the full characteristics of magneto-dielectric materials at multiple frequencies. The sensor is generally an upside down microstrip line structure. Circular and semicircular grooves are engraved at the top ground side to probe the material, and a voltage-controlled variable capacitance diode is added to play the role of frequency tuning. The proposed design provides two separate areas for permittivity and permeability sensing, with higher-strength electric and magnetic fields in each area. By analyzing the measured resonant frequency and quality factor of the microstrip line, the real and imaginary parts of the permittivity and permeability of the material can be determined. Different from other sensors, the proposed sensor can measure permittivity and permeability with two separate measurements using only one sample, and it can measure the permittivity and permeability at multiple frequencies. Numerical calculations and experimental data are given, which clearly support our design.