Highly Sensitive Dual-Notch Compact Complementary Meta Resonator for Low Permittivity

This article proposes a dual-notch metamaterial-based complementary resonator that offers high sensitivity, high q-factor, simple design, and low fabrication cost for low-permittivity solid material sensing applications. The design comprises a maze-shaped complementary ring resonator (MCSRR) with multiple split rings, enhancing its inductance coupled with a unique ring 50-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> impedance microstrip transmission line (MTL) makes this MCSRR a high-sensitivity sensor. The two resonant frequency notches are achieved at 2.88 and 4.05 GHz with q-factor of 780.75 and 1172.77, respectively. The performance of the sensor is investigated and calibrated using various dielectric materials with thicknesses between 0.25 and 1.25 mm and relative permittivity values between 2.2 and 11.2. A least square regression model is employed to predict the permittivity of the materials under test (MUT) using the measured resonant frequencies of the proposed MCSRR microwave sensor. Compared to the existing microwave sensors, the proposed MCSRR demonstrates superior sensitivity and accuracy in dielectric characterization.