High Sensitive Microwave Microfluidic Sensor Based on Split Ring Resonator for Determination Liquid Permittivity Characterization (original) (raw)
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High Sensitive Microwave Micro-Fluidic Sensor Using Split Ring Resonator
2020
Microwave resonators are commonly used as precise instruments for the measurements of dielectric and electromagnetic properties of materials such as the complex permeability and complex permittivity and surface resistance at microwave frequencies. Many medical and pharmaceutical applications, food industries, and chemical applications require accuracy in calculating complex permittivity of sample under test. In this work, the design and fabrication of high sensitive microwave microfluidic sensors are based on a split ring resonator for liquid permittivity characterization. A microwave microfluidic microstrip SRR is presented in this thesis for liquid sensing and characterization. The 3-D simulations of the sensor are implemented using COMSOL Multiphysics 5.4 to reach a good agreement between simulated and experimental results. The sensor is designed to operate at a frequency of 1.4 GHz and a quality factor of 360. The sensor has been tested with several solvents (water, ethanol, and chloroform) to verify its sensitivity where the resonant frequency and quality factor vary with each solvent. The shift in the resonant frequency and the change in the losses have been used to get the values of the complex permittivity of the solvents. The measured complex permittivity of the solvents has been compared with the theoretical values as there was a very good compatibility between them. Furthermore, we present a new approach for microfluidic sensing using an active split ring resonator (ASRR). ASRR with high sensitivity is presented for measure characterization of liquid with a very small liquid volume approximately 0.4 nL operations at L band. The 3-D simulations of the ASRR are implemented using Advanced Design System 2016.01 (ADS). RF amplifier LNA assists a passive planer microwave sensor inside an aluminum cylindrical cavity to be active SRR. This study consists of two parts; the first part is a calculation of the quality factor and losses of some common fluids (water,ethanol, chloroform, and petroleum ether) using both passive and active SRR to increase Q- factor from 250 to 814 with reducing the loss from 19.6 dB to 6.6 dB when passive SRR is loaded with an empty tube due to RF amplifier generate negative resistance and compensating energy and loss in the passive sensor. As the resolution of the sensor increases with the increase in the quality factor. The second part, via using an active SRR, sensing the high concentrations of sodium sulfite (1 - 3.17) M at 25°C and thus sensor can be used to measure salt concentrations in water. Microstrip stopband split ring resonator (SSRR) for microwave microfluidic is presented for measuring complex permittivity of liquid with different positions of microfluidic channel that operates at resonant frequency of 1 GHz. The sensor was fabricated and microfluidic channel is located in the gap groove with two different positions of the carrier where the electric field is as large as possible. The sensor has been tested with several solvents to verify its sensitivity where the electric field interacts with the liquid filled in a quartz tube and hence alter the SRR behavior. The electromagnetic properties (complex permittivity) of the solutions can be extracted from the change in the resonant frequency of the resonator due to the perturbation phenomenon.
Ultrahigh-Sensitivity Microwave Sensor for Microfluidic Complex Permittivity Measurement
IEEE Transactions on Microwave Theory and Techniques, 2019
The conventional resonant-type microwave microfluidic sensors made of planar resonators suffer from limited sensitivities. This is due to the existence of several distributed capacitors in their structure, where just one of them acts as a sensing element. This article proposes a very high-sensitivity microwave sensor made of a microstrip transmission line loaded with a shunt-connected series LC resonator. A large sensitivity for dielectric loadings is achieved by incorporating just one capacitor in the resonator structure. Applying sample liquids to the microfluidic channel implemented in the capacitive gap area of the sensor modifies the capacitor value. This is translated to a resonance frequency shift from which the liquid sample is characterized. The sensor performance and working principle are described through a circuit model analysis. Finally, a device prototype is fabricated, and experimental measurements using water/ethanol solutions are presented for verification of the sensing principle. Index Terms-Dielectric measurement, microfluidic sensor, microwave sensor, planar resonators.
Relative Permittivity Measurement of Microliter Volume Liquid Samples through Microwave Filters
Sensors
This paper proposes a concept of dielectric characterization of low-volume liquid samples using the coupling coefficient of filters. The concept is validated through a two-pole substrate integrated waveguide filter in which the liquid under test is mounted on the coupling section between the two resonators. Unlike the conventional resonator perturbation method reported many times in the literature, this technique uses the coupling coefficient for sensing. The liquid sample is collected in a capillary tube and carefully positioned on the coupling section of the filter; the coupling coefficient of the two resonators varies compared to the relative permittivity of the sample; thus, an empirical model is established. The proposed sensor has been tested to compute the permittivity of different alcohols. Binary solutions of ethanol and water have also been characterized to calculate the volume ratio and relative permittivity as a proof-of-concept. The obtained results show that the propos...
IEEE Sensors Journal, 2018
A metamaterial-based microwave sensor with complementary split ring resonator (CSRR) is implemented for dielectric characterization of liquids. The novelty in the proposed contactless sensor is the use of liquid samples placed normal to the sensor surface. Placed inside of glass capillary tubes, it is quickly possible to analyze the dielectric properties of liquids simply by replacing the capillary tubes with new samples. The liquid samples inside the glass capillary tubes modify the resonant frequency and Q factor of the CSRR sensor. Thereby a relation between the sensor resonant frequency, Q factor, and complex permittivity of the liquid samples can be estimated. A measurement setup was used to test the proposed sensor that exhibited successfully detection of 10% steps in binary mixtures of ethanol and water. The proposed sensor is compact, low-cost, contactless, reusable, easily fabricated, and easy to work.
Sensors, 2021
In this paper, a very high sensitivity microwave-based planar microfluidic sensor is presented. Sensitivity enhancement is achieved and described theoretically and experimentally by eliminating any extra parasitic capacitance not contributing to the sensing mechanism. The sensor consists of a microstrip transmission line loaded with a series connected shunt LC resonator. A microfluidic channel is attached to the area of the highest electric field concentration. The electric field distribution and, therefore, the resonance characteristics are modified by applying microfluidic dielectric samples to the sensing area. The sensor performance and working principle are described through a circuit model analysis. A device prototype is fabricated, and experimental measurements using water/ethanol and water/methanol solutions are presented for validation of the sensing mathematical model.
Integrated microwave resonant device for dielectric analysis of microfluidic systems
Journal of Physics: Conference Series, 2011
Herein we present a device for performing non-contact dielectric spectroscopy upon liquids in a microfluidic environment. The device is comprised of a compression-sealed polytetrafluoroethylene (PTFE) chip with an embedded coaxial resonator, which is overmoded for dielectric measurements at six discrete frequencies between 1 and 8 GHz. A novel capacitive coupling structure allows transmission measurements to be taken from one end of the resonator, and an optimised microchannel design maximises sensitivity and repeatability. The use of a PTFE substrate and a non-contact measurement gives excellent chemical and biological compatibility. A simple 'fingerprint' method for identifying solvents is demonstrated, whereby a sample is characterised by air-referenced changes in complex frequency. Complex permittivity values are also obtained via a perturbation theory-based inversion. A combination of experimental and simulated results is used to characterise the device behaviour, limits of operation and measurement uncertainty. The high stability of temporal measurements, coupled with the robustness of the design, make this device ideal for analytical chemistry and industrial process control.
A Metamaterial-Based Microwave Sensor for Liquid Dielectrics Characterization
Proceedings of the Proceedings of the 1st International Multi-Disciplinary Conference Theme: Sustainable Development and Smart Planning, IMDC-SDSP 2020, Cyperspace, 28-30 June 2020, 2020
In this work, we propose a metamaterial-based microwave sensor. The main body of the proposed sensor is a microstrip coupled complementary spiral rectangular resonator (CSRR). At resonance, a strong electric field is established along the sides of the CSRR creating a very sensitive area to change in the nearby of the dielectric environment. The enhanced proposed contactless sensor uses liquid samples placed normal to the sensor surface retained within capillary glass tubes. Quick analysis of the liquid dielectric properties is carried out by simply replacing the capillary tube with a new sample.The introduced liquid sample shifts the resonance frequency and alters the peak attenuation of the CSRR resonance. The liquid sample dielectric properties may be estimated by establishing an empirical relationship between the resonance characteristics and the liquid complex relative permittivity. In this work, we could improve our device by simple changing of the CSRR shape of a recently published work, this makes improvement on the characteristics of the sensor and lower its working frequency to 1.8GHz.
TELKOMNIKA Telecommunication Computing Electronics and Control, 2019
In this paper, a new design of microwave sensor with high Q-factor for liquid characterization is analyzed and investigated. The new microwave sensor is based on a gap waveguide cavity resonator (GWCR). The GWCR consists of upper plate, lower plate and array of pins on the lower plate. The liquid under test (LUT) is characterized by placing it inside the GWCR where the electric field concentrates using a quartz capillary that is passing through microfluidic channels. The results show that the proposed sensor has a high Q-factor of 4832. Moreover, the proposed sensor has the ability to characterize different types of liquids such as oils, ethanol, methanol and distilled water. The polynomial fitting method is used to extract the equation of the unknown permittivity of the LUT. The results show that the evaluated permittivity using the proposed sensor has a good agreement with the reference permittivity. Therefore, the proposed sensor is a good candidate for food and pharmaceutical applications.
IEEE Access, 2018
Differential permittivity sensors based on a pair of uncoupled microstrip lines, each one loaded with an open complementary split ring resonator (OCSRR), are proposed in this paper. The sensing principle is based on the measurement of the cross-mode insertion loss, very sensitive to asymmetric loading. Thus, by loading one of the OCSRRs with the reference sample, and the other one with the sample under test (SUT), the difference in the complex permittivity between both samples generates an asymmetry that gives rise to mode conversion. From the measurement of the cross-mode transmission coefficient, the dielectric properties of the SUT can be determined, provided those of the reference sample are well known. It is shown that by adding fluidic channels on top of the OCSRRs, the proposed sensor is useful for the measurement of the complex dielectric constant of liquids, and experimental results in mixtures of ethanol and deionized (DI) water and methanol in DI water, as a function of the ethanol/methanol content, are provided. Due to the high sensitivity of the proposed differential sensor to detect small perturbations (asymmetries), the structure is also of interest for the accurate measurement of solute concentrations in liquid solutions. In this paper, the structure is applied to monitor sodium content in aqueous solutions, and it is found that sodium concentrations as small as 0.25 g/L can be resolved. INDEX TERMS Microwave sensors, dielectric characterization, permittivity sensors, differential sensors, split ring resonators, microstrip technology. JAVIER MATA-CONTRERAS was born in Málaga, Spain, in 1976. He received the Ingeniería de Telecomunicación degree and the Ph.D. degree with a thesis Distributed Amplifiers and Mixers With Transmission Lines Based on Metamaterials from the Universidad de Málaga (UMA), in 2000 and 2010, respectively. In 2000, he joined the Department of Ingeniería de Comunicaciones, UMA, as an Assistant Professor. He is currently with CIMITEC and the Universitat Autònoma de Barcelona as a Visiting Professor. His research interests include active and passive microwave devices, and active distributed circuits based on metamaterials, among others.
Differential Microstrip Sensor for Complex Permittivity Characterization of Organic Fluid Mixtures
Sensors
A microstrip highly sensitive differential sensor for complex permittivity characterization of urine samples was designed, fabricated and tested. The sensing area contains two pairs of open-stub resonators, and the working frequency of the unloaded sensor is 1.25 GHz. The sensor is easily implemented on an affordable substrate FR-4 Epoxy with a thickness of 1.6 mm. A Teflon beaker is mounted on the sensor without affecting the measurements. Numerically, liquid mixtures of water and urine at different percentages were introduced to the proposed sensor to evaluate the frequency variation. The percentage of water content in the mixture varied from 0% (100% urine) to 100% (0% urine) with a step of 3.226%, thus giving 32 data groups of the simulated results. Experimentally, the mixtures of: 0% urine (100% water), 20% urine (80% water), 33% urine (66% water), 50% urine (50% water), 66% urine (33% water), and 100% urine (0% water) were considered for validation. The complex permittivity of...