Metamaterial microwave sensor with ultrahigh Q-factor based on narrow-band absorption

A novel metamaterial sensor with ultrahigh Q-factor of 665.85 and 1883.3 at 5.46 GHz and 11.3 GHz is presented in this paper, which consists of a metal pattern with cross structure and ring (CSR), a dielectric slab FR4 and a metal backplate. Based on the principle of the absorber, the Q-factor of the two resonance frequency points is improved by optimizing the ring and cross structure to strengthen the resonance. It is because of its wide angle incidence, insensitive polarization, and narrow-band absorptivity greater than 90 %, which is very conducive to the design of material refractive index sensor. Equivalent circuit method is used to analyze the characteristic of the metamaterial structure and the experimental results are in good agreement with the simulations. By loading three giving materials, the sensing function is analyzed and verified in experiments. The design has the advantages of ultrahigh Q-factor, angle and polarization insensitivity, and has potential application prospects in metamaterial sensing.