{"content"=>"Simultaneous Detection of Two Chemicals Using a TE-Mode Substrate-Integrated Waveguide Resonator.", "sub"=>{"content"=>"20"}} (original) (raw)
Related papers
Sensors (Basel, Switzerland), 2018
The detection of multiple fluids using a single chip has been attracting attention recently. A TM quarter-mode substrate-integrated waveguide resonator designed at 5.81 GHz on RT/duroid 6010LM with a return loss of 13 dB and an unloaded quality factor of Q ≈ 13 generates two distinct strong electric fields that can be manipulated to simultaneously detect two chemicals. Two asymmetric channels engraved in a polydimethylsiloxane sheet are loaded with analyte to produce a unique resonance frequency in each case, regardless of the dielectric constants of the liquids. Keeping in view the nature of lossy liquids such as ethanol, the initial structure and channels are optimized to ensure a reasonable return loss even in the case of loading lossy liquids. After loading the empty channels, Q is evaluated as 43. Ethanol (E) and deionized water (DI) are simultaneously loaded to demonstrate the detection of all possible combinations: [Air, Air], [E, DI], [DI, E], [E, E], and [DI, DI]. The...
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 Microfluidic-Integrated SIW Lab-on-Substrate Sensor for Microliter Liquid Characterization
IEEE Sensors Journal, 2016
A novel microfluidic-integrated microwave sensor with potential application in microliter-volume biological/biomedical liquid sample characterization and quantification is presented in this paper. The sensor is designed based on the resonance method, providing the best sensing accuracy, and implemented by using a substrate-integratedwaveguide (SIW) structure combining with a rectangular slot antenna operating at 10 GHz. The device can perform accurate characterization of various liquid materials from very low to high loss, demonstrated by measurement of deionized (DI) water and methanol liquid mixtures. The measured relative permittivity, which is the real part of complex permittivity, ranges from 8.58 to 66.12, which is simply limited by the choice of test materials available in our laboratory, not any other technical considerations of the sensor. The fabricated sensor prototype requires a very small liquid volume of less than 7 µl, while still offering an overall accuracy of better than 3 %, as compared to the commercial and other published works. Key advantages of the proposed sensor are that it combines 1.) a very low-profile planar and miniaturized structure sensing microliter liquid volume; 2.) ease of design and fabrication, which makes it cost-effective to manufacture and 3.) noninvasive and contactless measurements. Moreover, since the microfluidic subsystem can potentially be detached from the SIW microwave sensor and, afterward, replaced by a new microfluidic component, the sensor can be reused with no life-cycle limitation and without degrading any figure of merit.
Al-Furat Journal of Innovations in Electronics and Computer Engineering, 2020
a microwave microfluidic microstrip spilt ring resonator is presented in this paper for liquid sensing and characterization. The sensor is designed to operate at frequency of 1.4 GHz and quality factor of 360. The sensor has been tested with several solvents to verify its sensitivity where the resonant frequency and losses vary with each solvent. The shift in the resonant frequency and the change in the insertion loss have been used to extract the values of the complex permittivity of the solvent. The measured complex permittivities of the solvents have been compared with the theoretical values with very good agreement. This sensor can be utilized in many industrial and medical application where the characterization of liquids are needed.
Scientific Reports
In this study, a critical evaluation of analyte dielectric properties in a microvolume was undertaken, using a microwave biochemical sensor based on a circular substrate integrated waveguide (CsIW) topology. these dielectric properties were numerically investigated based on the resonant perturbation method, as this method provides the best sensing performance as a real-time biochemical detector. To validate these findings, shifts of the resonant frequency in the presence of aqueous solvents were compared with an ideal permittivity. The sensor prototype required a 2.5 µL volume of the liquid sample each time, which still offered an overall accuracy of better than 99.06%, with an average error measurement of ±0.44%, compared with the commercial and ideal permittivity values. The unloaded Q u factor of the circular substrate-integrated waveguide (CsIW) sensor achieved more than 400 to ensure a precise measurement. At 4.4 GHz, a good agreement was observed between simulated and measured results within a broad frequency range, from 1 to 6 GHz. The proposed sensor, therefore, offers high sensitivity detection, a simple structural design, a fast-sensing response, and cost-effectiveness. The proposed sensor in this study will facilitate real improvements in any material characterization applications such as pharmaceutical, bio-sensing, and food processing applications. The field of material characterization in enclosures has generated a major interest in research due to its wide application in various industries. Recent developments in microwave sensor technology have heightened the need for more accurate instruments for characterizing materials in order to fulfil the demands of industry such as chemical composition analysis, food processing monitoring, agriculture-based research, pharmaceutical detection, and bio-sensing 1. Knowledge of material properties is, of course, crucial for any understanding of proper scientific information. The dielectric characteristics of physical and chemical materials and the biomechanism of certain reactions need to be studied extensively in order to conduct an initial evaluation of materials used. Numerous studies have attempted to demonstrate, and various methods have been developed to produce high-efficiency sensors for fast detection, precise measurement, and reliable sensing capabilities 2-8. For example, reflection, transmission/reflection, resonator, and resonant perturbation methods 9. These types of methods can be realized with one or two-port network systems based on the specification and functionality of the sensor itself. Each method, nevertheless, is limited to specific frequency bands, selective physical properties of materials, and a narrow application by its own constraint 10,11. Furthermore, these group of microwave methods are depending on S-parameters behaviour to detect and extract the properties of material. To be exact, the change frequency shifting of S-parameters and the E-fields distribution on sensor structure would reflect the accuracy and sensitivity of the sensor. However, number of studies show that significant differences do exist, in a way to sense and characterize the material properties. This technique is called Surface Plasmon Resonance (SPR). Basically, SPR is an optical
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.
Complementary Split-Ring Resonator-Loaded Microfluidic Ethanol Chemical Sensor
Sensors, 2016
In this paper, a complementary split-ring resonator (CSRR)-loaded patch is proposed as a microfluidic ethanol chemical sensor. The primary objective of this chemical sensor is to detect ethanol's concentration. First, two tightly coupled concentric CSRRs loaded on a patch are realized on a Rogers RT/Duroid 5870 substrate, and then a microfluidic channel engraved on polydimethylsiloxane (PDMS) is integrated for ethanol chemical sensor applications. The resonant frequency of the structure before loading the microfluidic channel is 4.72 GHz. After loading the microfluidic channel, the 550 MHz shift in the resonant frequency is ascribed to the dielectric perturbation phenomenon when the ethanol concentration is varied from 0% to 100%. In order to assess the sensitivity range of our proposed sensor, various concentrations of ethanol are tested and analyzed. Our proposed sensor exhibits repeatability and successfully detects 10% ethanol as verified by the measurement setup. It has created headway to a miniaturized, non-contact, low-cost, reliable, reusable, and easily fabricated design using extremely small liquid volumes.
Meta-atom microfluidic sensor for measurement of dielectric properties of liquids
Journal of Applied Physics, 2017
High sensitivity microwave frequency microfluidic sensing is gaining popularity in chemical and biosensing applications for evaluating the dielectric properties of liquid samples. Here, we show that a tiny microfluidic channel positioned in the gaps of a dual-gap meta-atom split-ring resonator can exploit the electric field sensitivity to predict the dielectric properties of liquid samples. Employing an empirical relation between resonant characteristics of the fabricated sensor and the complex permittivity of water-ethanol or water-methanol mixtures produces good congruence to standardized values from the literature. This microfluidic sensor offers a potential lab-on-chip solution for liquid dielectric characterization without external electrical connections.
Development of Novel Microwave and Millimetre-wave Sensors for Liquid Characterisation
2017
This research investigates the characterisation of liquids using primarily substrate integrated waveguides and extending this to other interesting conventional transmission lines. Focus is drawn to liquid mixture quantification, which is significant in the distinction of the quantity of one biological or chemical liquid from another. This work identified and confirmed that microwave resonance methods are best suited to perform mixture quantification due to their high sensing accuracy and inherent single point detection. The tracking of the resonant frequency change with either the corresponding return loss or insertion loss (depending on the type of resonant structure) gives a good solution in this regard. On the other hand, it was affirmed that transmission line methods are best suited for general broadband characterisation of a particular liquid. Three major outputs were achieved in this research work, namely: (i) In-SIW millimetre wave sensor; (ii) SIW slot antenna microlitre sen...