Metamaterial Sensor with Double Octagonal Enclosed Star Shape for Microwave Sensing with High Performance

This research proposes a double octagonal enclosed star shape split-ring resonator (SRR) structure for sensing applications in the frequency range of 4-9 GHz. The dimensions of the structure are quite small, measuring 20×20mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The absorption value is remarkably high, reaching 99.9% at 8.26 GHz and 85.43% at 5.448 GHz. This absorber exhibits insensitivity to incidence angles and polarization angles. An additional sensor layer can be included at the rear of this structure to evaluate the sensing capabilities. The performance of the system is exceptional in terms of frequency shifting. The resonance frequency shifts by 119.6 MHz for clean and waste oil, 108 MHz for clean and dirty transformer oil, 132 MHz for branded and unbranded diesel, and 108 MHz for olive and corn oil. Furthermore, the analysis also includes the examination of the electric field (E-field), magnetic field (H-field), and surface current.The equivalent circuit is also analyzed to verify the simulation result. Due to its small size, uncomplicated construction, and exceptional sensing capabilities, this absorber can be utilized in a wide range of sectors, including chemical, oil, and microfluidics, for the detection of different liquid samples.