Water-based metamaterial absorber for temperature modulation

Abstract In this study, a transmissive all-dielectric metamaterial absorber comprising a photosensitive resin and water layers was proposed. The water layers comprised coin rings, crosses, and fan shapes. The as-obtained absorber achieved >90% absorption of electromagnetic waves within the frequency range of 18.4–41.7 GHz, and the absorption bandwidth covered the Ka-band. Because of the symmetric structure of the designed metamaterial, it was not influenced by polarization. The inherent dispersive properties of water result in a dielectric constant that varies significantly with temperature. This led to fluctuations in the absorption efficiency of the designed metamaterial to different degrees with changes in temperature. The analysis of electric and magnetic fields distributions revealed that the primary absorption physical mechanism of the designed metamaterial originated from magnetic resonances in the water layers. The proposed transmissive metamaterial absorber has potential applications in high-sensitivity thermal and temperature sensors.