Planar microwave sensor with high sensitivity for material characterization based on square split ring resonator

• Main Author: Roslan, Harry Sucitra
• Format: Thesis
• Language: English; English
• Published: 2023
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/28281/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=124151

Microwave sensors for material characterization are the most widely used sensors in the food sector, quality control, biomedical, and industrial applications. One of the prospective methods for very precise dielectric material characterization measurements at a single or discrete frequency is the microwave resonant approach. Historically, waveguide, dielectric, and coaxial resonators have been used to characterize materials because they offer great sensitivity and precision. However, resonator sensors are typically large, expensive to produce, and require a large amount of material to detect the prior sample of the material being tested. Therefore, because of their benefits of being small in size, inexpensive, and simple to manufacture, planar resonant methods have become the most preferred approach in recent years. However, the poor sensitivity and low Q-factor value of this method limit the applicability for material characterization. Thus, this thesis introduces a single-band metamaterial to overcome the weakness of this technique by using the perturbation method in which the dielectric properties of the resonator affect the Q-factor and resonance frequency. This proposed sensor operated at 2.5 GHz in the range of 1 GHz to 4 GHz for material characterization of solid and liquid samples. These sensors were constructed using RT/Duroid Roger 5880 as a substrate with a dielectric constant of 2.2, loss tangent of 0.0009, and copper thickness of 17.5 μm. The integrated microfluidic sensing case is designed using Epoxy Resin. The epoxy resin has better corrosion resistance and is less influenced by heat and water than other polymeric matrices. The liquid sample will be injected into these microfluidic cases that will be placed at the maximum concentration of E-flux at the top of the copper structure. E-flux areas with high concentrations are more susceptible to dielectric changes. The proposed sensor requires the same size of the solid sample with a different thickness of the sample and the same amount of liquid sample to be tested which is 0.3.