Ahmed Alzamil, Muhammad Amir Khalil, Wong Hin Yong, Abdulmajeed M. Alenezi, Mohamad A. Alawad, Abdulwadoud A. Maash, Mohamed S. Soliman, Riaz Hussain, Mohammad Tariqul Islam
This study presents a highly efficient metamaterial (MTM) absorber designed for precise sensing applications, particularly for distinguishing edible oils based on their dielectric properties. Utilising a compact maze-shaped structure comprising a copper resonator and a Rogers 5880 substrate, the absorber achieves near-perfect (> 99 %) absorption efficiency across the 2–5 GHz frequency range. The absorber's geometric parameters were investigated in detail, revealing significant improvements in multi-band performance and resonance tuning with incremental increases in the resonator's complexity. Comprehensive simulations conducted using CST Microwave Studio and validated through equivalent circuit modelling demonstrated strong agreement, establishing a robust design methodology. Experimental verification confirmed the absorber's sensitivity, demonstrating clear differentiation among mustard, coconut, and sunflower oils through distinct resonance-frequency shifts attributable to their dielectric constants. The sensor achieved an exceptional quality factor (Q = 170), high sensitivity (0.85 GHz per dielectric unit), and superior absorption performance, positioning it as a promising candidate for industrial applications in quality control and food safety.