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In this paper, a new metamaterials-based hypersensitized liquid sensor integrating omega-shaped resonator with microstrip transmission line is proposed. Microwave transmission responses to industrial energy-based liquids are investigated intensively from both numerical and experimental point of view. Simulation results concerning three-dimensional electromagnetic fields have shown that the transmission coefficient of the resonator could be monitored by the magnetic coupling between the transmission line and omega resonator. This sensor structure has been examined by methanol-water and ethanol-water mixtures. Moreover, the designed sensor is demonstrated to be very sensitive for identifying clean and waste transformer oils. A linear response characteristic of shifting the resonance frequency upon the increment of chemical contents/concentrations or changing the oil condition is observed. In addition to the high agreement of transmission coefficients (S21) between simulations and experiments, obvious resonant-frequency shift of transmission spectrum is recognized for typical pure chemical liquids (i.e., PEG 300, isopropyl alcohol, PEG1500, ammonia, and water), giving rise to identify the type and concentration of the chemical liquids. The novelty of the work is to utilize Q factor and minimum value of S21 as sensing agent in the proposed structure, which are seen to be well compatible at different frequencies ranging from 1-20 GHz. This metamaterial integrated transmission line-based sensor is considered to be promising candidate for precise detection of fluidics and for applications in the field of medicine and chemistry.

The detection of branded and unbranded chemical materials is essential for the quality control assessment. In this work, a metamaterial inspired sensor is designed and fabricated, which incorporates oval-shaped wing resonators, in order to use to detect branded and unbranded diesels in the X-band frequency region. The simulation studies were carried out by using the Computer Simulation Technology (CST) Microwave studio. A transmission line was introduced into the sensor design and genetic algorithm was used to optimize the proposed structure. Parametric study was investigated by changing the permittivity, permeability of the sensor layer, width of the transmission line, materials of the substrate layer, and width of the resonator. Results showed that different factors can be considered to sense the chemical materials including the shift in resonant frequency and amplitude variation in the reflection or transmission spectrum. It was found that the sensible variation in the transmission value is about −3.2 dB, which is superior to that reported in literature. It was concluded that the sensor is highly sensitive to distinguish the branded diesel from the unbranded one, which makes it viable for detecting fluidics in the chemical industry and medicine.

A triple band metamaterial absorber in the terahertz range, incorporating a three closed circle ring resonator, was designed and fabricated on flexible polyethylene terephthalate “PET” substrate. The proposed design was investigated theoretically and experimentally. Computer simulation technology “CST” was used to study the designed structure, while lithography technique was used to fabricate the absorber and terahertz time-domain spectroscopy was utilized to measure the reflectivity. Results showed the presence of three intensive peaks at the resonance frequencies of ‘0.43, 0.61, and 0.88 THz’, which correspond to the absorptivity of 98%, 91%, and 98%, respectively. The sensitivity of the three peaks was found to be ‘70.5, 133, and 149.5 GHz/RIU’, respectively. The parametric studies and field distributions were analysed. Furthermore, the proposed design exhibited polarization insensitivity for both transverse electric “TE” and transverse magnetic “TM” modes from 00 to 900. It was concluded that the proposed design can be specifically viable for some important applications such as ‘THz’ images, filtering, biological sensing, and optical communications.

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