Novel Complementary Multiple Concentric Split Ring Resonator for Reliable Characterization of Dielectric Substrates With High Sensitivity

Accurate characterization of dielectric substrates with high sensitivity remains an important challenge in a variety of industrial applications. This article proposes an innovative strategy to address this challenge by developing and optimizing a unique complementary multiple concentric split ring resonator (CMC-SRR). The major goal is to propose a sensor design with increased sensitivity and reliability for dielectric characterization. The CMC-SRR sensor uses simple complementary SRR structures and a 50-
$\Omega $
microstrip transmission line (MTL) to resonate at 17 GHz. To obtain optimal performance, a sensitivity analysis is performed, taking into account the structure’s shape, size, thickness, and permittivity of the material under test (MUT). Fabrication specifics include the use of an LPKF ProtoLaser on a 0.51-mm-thick Rogers 5880 substrate, which allows for more efficient and cost-effective manufacturing. An inverse regression model is created to forecast the permittivity of unknown materials using measured resonance frequencies and sample thickness. Our research yielded significant results, including a relative sensitivity greater than 8% and a maximum permittivity prediction error of less than 7%. These findings outperform current state-of-the-art complementary resonator-based sensors described in the literature.