Complementary split rectangular resonators based metamaterial sensor for dielectric material's Measurements: Design and comparative analysis

Complementary Split Rectangular Resonators based Metamaterial sensor is designed and simulated on HFSS for the non-destructive evaluation of dielectric substrates. S-parameters measurements are made to extract the complex permittivity and permeability of the structures. Proposed metamaterial sensor operating in the S-band are fabricated and tested for verification. Comparative analysis is also performed among four structures namely Rectangular, Circular, Square and Triangular. Proposed sensor is a two port structure. Top side of all the sensors are microstrip line while aforementioned structures are etched in the bottom of the substrate. After the analysis, rectangular structure is found better in respect of resonant frequency and sharp notch depth which is -19.6 dB at 3.78 GHz. Rectangular structure based microwave sensor is then fabricated. Electromagnetic properties of effective permittivity (ϵ) and permeability (μ) of the proposed sensor is calculated numerically. Proposed sensor is fabricated by using low cost FR4 material. The dimensions of FR4 substrate are (w = 24, l = 30, h = 0.8) Dimensions of the proposed rectangular structure is w = 4, l = 6 and h = 0.035. Transmission coefficient magnitude (S₂₁) is measured by using Vector Network Analyzer (E8363B). The response of the rectangular sensor is like a narrow band rejects filter. This methodology is very simple and needs only to calculate the resonant frequency which reduces not only the cost but also computation time. Ease in fabrication, and integration with other microwave devices are the main benefits of complementary metamaterial microwave sensors. Proposed sensor can be applicable in the fields of bio-sensing, security and designing of 2D sensor array for surface imaging.