The microwave dielectric behavior of sandwich-like Ti₃C₂ MXene nanosheets with efficient microwave absorption was investigated by a combination of experiments and simulations. The obvious frequency dispersion effect and the double-peaked feature of dielectric spectra in Ti₃C₂ MXene nanosheets could be observed over the frequency range of 2–18 GHz, giving rise to superior microwave attenuation capability. Furthermore, a revised Drude-Lorentz model was proposed to explain the peaked feature of permittivity, and simulated results were demonstrated to agree well with the experimental measurements. It was concluded that the hopping migration between Ti₃C₂ MXene nanosheets with longer relaxation time than “micro-dipole” relaxation within nanosheets makes a superior contribution to overall absorbing performance.

In this paper, a new metamaterials-based hypersensitized liquid sensor integrating omega-shaped resonator with microstrip transmission line is proposed. Microwave transmission responses to industrial energy-based liquids are investigated intensively from both numerical and experimental point of view. Simulation results concerning three-dimensional electromagnetic fields have shown that the transmission coefficient of the resonator could be monitored by the magnetic coupling between the transmission line and omega resonator. This sensor structure has been examined by methanol–water and ethanol–water mixtures. Moreover, the designed sensor is demonstrated to be very sensitive for identifying clean and waste transformer oils. A linear response characteristic of shifting the resonance frequency upon the increment of chemical contents/concentrations or changing the oil condition is observed. In addition to the high agreement of transmission coefficients (S21) between simulations and experiments, obvious resonant-frequency shift of transmission spectrum is recognized for typical pure chemical liquids (i.e., PEG 300, isopropyl alcohol, PEG1500, ammonia, and water), giving rise to identify the type and concentration of the chemical liquids. The novelty of the work is to utilize Q factor and minimum value of S21 as sensing agent in the proposed structure, which are seen to be well compatible at different frequencies ranging from 1–20 GHz. This metamaterial integrated transmission line-based sensor is considered to be promising candidate for precise detection of fluidics and for applications in the field of medicine and chemistry.