Double-layered metamaterial-based resonator operating at millimetre wave for detection of dengue virus

The interest in microwave technology for biological applications using metamaterial as sensing element is increasing due to strong electric field compared to traditional microwave sensors. The operation at millimetre-wave frequencies further enhances the field intensity leading to increased sensitivity, which can be used in the detection of the dengue virus and it can be vital in controlling the disease. The millimetre-wave metamaterial-based resonators are presented in this thesis to characterise blood’s dielectric properties in the case of the dengue virus. The correlation coefficient, t-test, and cross-correlation were applied on S11 phase responses. During measurements, tap water was used instead of blood, and methylated alcohol was added to the water to lower its permittivity, mimicking the dielectric response of infected blood. First, a single-layered design with an engraved space to hold blood samples is presented as a proof of concept for blood-sensing and the application of statistical models. This sensor showed a resonance shift of 0.22 GHz due to an 8 unit decrease in blood’s permittivity. In contrast, three (3) designs of two-layered sensors are proposed with replaceable sensing layers suitable for repeated measurements. Double-layered Sensor 1 showed resonance at 36.28 GHz for normal blood. The perturbation observed was 0.88 GHz when the blood’s permittivity was reduced by 8 units. Sensor 2 showed a resonance shift from 27.22 GHz to 29.82 GHz with the 8 unit change in blood’s permittivity. Sensor 3 showed a lesser resonance shift, which is 0.44 GHz. However, the double-layered Sensor 3 has the edge over other designs in terms of its performance in all statistical methods. In double-layered sensors, the replaceable sensing layer provides quick and accurate results. As a result, the sensors presented here can detect the dengue virus using a simple finger-prick blood extraction method

Double-Layered Metamaterial Resonator Operating At Millimetre Wave FOR Detection Of Dengue Virus

In this paper, a metamaterial-based resonator is proposed for the detection of dengue infection. The replaceable top layer can measure the dielectric characteristics of blood samples to detect the dengue virus. The sensor observed a shift in the resonant frequency towards higher frequencies with the reduction in the blood's permittivity. The sensor showed a 0.325 GHz shift in resonance per unit change in the dielectric permittivity. To corroborate the sensor’s practical sensing capability, a sensor prototype was fabricated and validated with alcohol-aqueous solutions. The sensor exhibited shifting of resonance towards lower frequencies with the addition of water contents in methylated alcohol. With the enhanced sensitivity and repeatable measuring capability, the results suggested that this sensor can be applied with real-time applications on the Internet of Medical Things (IoMT) for early remote detection of the dengue outbreak

Glucose level detection using millimetre-wave metamaterial-inspired resonator

Millimetre-wave frequencies are promising for sensitive detection of glucose levels in the blood, where the temperature effect is insignificant. All these features provide the feasibility of continuous, portable, and accurate monitoring of glucose levels. This paper presents a metamaterial-inspired resonator comprising five split-rings to detect glucose levels at 24.9 GHz. The plexiglass case containing blood is modelled on the sensor’s surface and the structure is simulated for the glucose levels in blood from 50 mg/dl to 120 mg/dl. The novelty of the sensor is demonstrated by the capability to sense the normal glucose levels at millimetre-wave frequencies. The dielectric characteristics of the blood are modelled by using the Debye parameters. The proposed design can detect small changes in the dielectric properties of blood caused by varying glucose levels. The variation in the transmission coefficient for each glucose level tested in this study is determined by the quality factor and resonant frequency. The sensor presented can detect the change in the quality factor of transmission response up to 2.71/mg/dl. The sensor's performance has also been tested to detect diabetic hyperosmolar syndrome. The sensor showed a linear shift in resonant frequency with the change in glucose levels, and an R2 of 0.9976 was obtained by applying regression analysis. Thus, the sensor can be used to monitor glucose in a normal range as well as at extreme levels

Detection of Ethanol Concentration in Liquid Using a Double-Layered Resonator Operating at 5G-mm-Wave Frequencies

A new sensing technique for rapidly detecting ethanol concentration in aqueous solutions based on electromagnetic resonance is discussed. The sensor has two substrate layers and operates at 5G-mm-wave frequencies. An experimental study of the new resonator's configuration determines the sensor's sensitivity. During the measurements, 6 samples were modeled with varying amounts of ethanol concentration in the water. The results showed that S 11 resonance moves linearly towards higher frequencies as the ethanol content increases. The resonant frequency shifted at 0.178 GHz per 10% increase in ethanol towards higher frequencies. As a result, the proposed 5G-mm-wave-sensing technique based on a replaceable sensing layer was proved to be suitable for rapid, accurate, and low-cost alcohol content detection in liquids

Millimetre-Wave Metamaterial-Based Sensor for Characterisation of Cooking Oils

The characterisation of the cooking oils presents a significant challenge due to minor changes in their dielectric behaviour. In this paper, a new metamaterial-based sensor incorporating a split-ring resonator (SRR) with a microstrip transmission line is presented to characterise cooking oils. The design demonstrates metamaterial characteristics of negative permittivity and permeability simultaneously at the resonance frequency. Furthermore, its operation in the range of millimetre-wave frequencies can further enhance its sensitivity, especially for liquid materials. The sensor’s novelty is the operation at millimetre-wave frequencies that offers a high shift in the transmission coefficient while operating at 30 GHz. The sensor’s performance analysis is undertaken by using six MUTs with dielectric constants ranging from 0.126 to 4.47. The presented structure designed on 12 × 8 mm2 Rogers substrate offers a sensitivity of 1.12 GHz per unit change in dielectric constant. The phase's shift demonstrates a lower percentage error than the amplitude and linearly moves towards higher frequencies with the increase in dielectric constant and tangent loss of MUT. The designed sensor can be prominently useful for detecting liquids' chemical characteristics in chemistry and medicine fields