Reconfigurable microwave SIW sensor based on PBG structure for high accuracy permittivity characterization of industrial liquids
TL;DR: In this paper, a cavity-based microwave sensor for permittivity determination of industrial liquids is presented, which is developed on a Substrate Integrated Waveguide (SIW) and is equipped with a photonic band gap method and variable capacitors.
Abstract: In this paper, we present a novel tunable microwave sensor for permittivity determination of industrial liquids. The proposed sensor is cavity based which is developed on a Substrate Integrated Waveguide (SIW). To enhance the characterization accuracy, the reconfigurable sensor is equipped with a Photonic Band Gap method and variable capacitors. Moreover, we employ the cavity perturbation technique in order to calculate the permittivity. In the characterization process, we obtain the permittivity of an unknown material by considering a resonant frequency shift. In fact, a capacitance is the main parameter for controlling the sensor resonance. We herein change this capacitance via reconfigurable SIW cavity and applying different materials. The proposed tunable architecture lets us study the material characteristic in the wider frequency range. The structure is designed in 5–6 GHz in order to determine the electromagnetic behavior of a brand new and used transformer oil samples. The results present a highly accurate permittivity of these oil samples. Hence, the proposed method and setup is not only suitable for oil ageing programs, but also applicable for other industrial liquid applications.
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TL;DR: In this article, a real-time non-invasive microwave microfluidic sensor for measuring glucose concentration in aqueous solutions is presented, which is made of an open-ended microstrip transmission line loaded with a complementary split-ring resonator (CSRR).
Abstract: This article presents the design and analysis of a real-time non-invasive microwave microfluidic sensor for measuring glucose concentration in aqueous solutions. The sensor is made of an open-ended microstrip transmission line loaded with a complementary split-ring resonator (CSRR). The CSRR shows a very intense electric field concentration at resonance, which is highly sensitive to the dielectric sample loading. A microfluidic channel is designed to deliver the glucose solutions to the sensitive area of the device. By applying liquid samples to the channel, a resonance frequency shift is detectable in the reflection coefficient (S11) of the device. This in turn leads to a change in the |S11|. Both of the frequency shift and Δ|S11| can be used to measure the glucose level in the solution. Mathematical models are developed based on the measurement results of the glucose-water solutions using the resonance frequency shift and Δ|S11|. The developed sensing models are then used for detecting the glucose levels down to physiological values using the designed biosensor. The results prove the potential compatibility of the proposed biosensor for human glycaemia monitoring.
118 citations
TL;DR: In this article, the authors proposed a dual-detection microfluidic chemical sensor based on quartermode spoof localized surface plasmon (LSP) resonator with higher sensitivity among all the dual/multichannel microwave chemical sensors.
Abstract: In this paper, benefitting from the presence of an ultrathin corrugated metal–insulator–metal ring resonator, for the first time, we proposed a dual-detection microfluidic chemical sensor based on quarter-mode spoof localized surface plasmon (LSP) resonator with higher sensitivity among all the dual/multichannel microwave chemical sensors. First, we study full-mode spoof plasmonic resonator and we show that the resonance modes of the quarter-mode structure are exactly one-fourth of the full-mode structure. By placing two asymmetric microfluidic channels in the strongest E-field regions, the capability of detecting two aqueous solutions is feasible. By utilizing a 85070E performance probe connected to vector network analyzer, we determined the relative permittivity and loss tangent of fluids under test. Then, the fabricated prototype was tested, and our experimental results collaborate well our simulation predictions. Our proposed RF sensor exhibits 87% growth in sensitivity () compared with the most sensitive multichannel microwave chemical sensor that previously existed. Furthermore, we show that our elaborately designed sensor has the potential to detect chemicals with very close dielectric constant corresponding to 1,4-Dioxin, Cyclohexane, n-Hexane with the relative permittivity of 2.12, 2.012, 1.95, respectively.
23 citations
TL;DR: A sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity.
Abstract: In this paper, a sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity. Adding vertical strips tightly coupled to the outer ring of the SRR leads to the appearance of two resonant frequencies at 1.24 GHz and 2.08 GHz. This modified geometry also assures an improved sensitivity. Using the full wave electromagnetic solver, both the unloaded and loaded sensors are investigated. The numerical simulations are used to develop a mathematical model based on a curve fitting tool for both resonant frequencies, allowing to obtain analytical relations for real and imaginary parts of permittivity as a function of the sample’s thickness and quality factor. The sensor is designed and fabricated on 1.6 mm thick FR-4 substrate. The measurements of different samples, such as transparent glass, acrylic glass, plexiglass, and Teflon, confirm that the modified SRR sensor is easy to implement and gives accurate results for all cases, with measurement errors smaller than 4.5%. In addition, the measurements highlight the importance of the second resonant frequency in the cases in which numerical limitations do not allow the usage of the first resonant frequency (1 mm thick sample).
21 citations
Cites methods from "Reconfigurable microwave SIW sensor..."
...It is utilized in a large range of applications such as: Material description [1,2], tests of organic tissue [3,4] microfluidics [5–8], bio sensing [9–11], ecological operators [12,13], and quality control in the food industry [14,15]....
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TL;DR: A liquid dielectric constant sensor based on a cubic container structure is proposed for the first time, which can enhance the electric field intensity in the measuring area and achieve excellent performance.
Abstract: In order to improve the sensitivity of liquid dielectric constant measurements, a liquid dielectric constant sensor based on a cubic container structure is proposed for the first time. The cubic container, which consists of a dielectric substrate with a split resonant ring (SRR) and microstrip lines, can enhance the electric field intensity in the measuring area. High sensitivity can be obtained from measuring the dielectric constant with the characteristics of the structure resonate. The research results show that the resonant frequency of the sensor is shifted from 7.69 GHz to 5.70 GHz, with about a 2 GHz frequency offset, when the dielectric constant of the sample varied from 1 to 10. A resonance frequency offset of 200 MHz for the per unit dielectric constant is achieved, which is excellent regarding performance. The permittivity of oil with a different metal content is measured by using the relation between the fitted permittivity and the resonant frequency. The relative error is less than 1.5% and the sensitivity of measuring is up to 3.45%.
18 citations
Cites background from "Reconfigurable microwave SIW sensor..."
...Reference [21] loads the photonic band gap and variable capacitance on the substrate-integrated waveguide....
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...Acc rding to the definition of sensitivity [21,35],...
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...According to the definition of sensitivity [21,35],...
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TL;DR: In this article, the authors presented a compact, cost-effective, and contactless fractal modified electromagnetic bandgap structure (EBG)-based microwave sensing platform for dielectric characterization of liquids by analyzing the variation in the reflection coefficient of an antenna.
Abstract: This article presents a compact, cost-effective, and contactless fractal modified electromagnetic bandgap structure (EBG)-based microwave sensing platform for dielectric characterization of liquids by analyzing the variation in the reflection coefficient of an antenna. The reported design is composed of a triangular-shaped antenna ( $0.323\lambda _{\mathrm {o}}\times 0.323\lambda _{\mathrm {o}}$ ) placed over a $3 \times 3$ array of Cesaro fractal-based EBG plane ( $0.67\lambda _{\mathrm {o}} \times 0.67\lambda _{\mathrm {o}}$ ) operating at 2.45 GHz. A significant enhancement of the ${E}$ -field in the sensing region has been achieved with the incorporation of Cesaro fractals in the EBG plane which results in increased sensitivity and compactness. To validate its performance, absolute solutions of butan-1-ol, methanol, and water are loaded, and a maximum measured sensitivity of 0.875% and a maximum quality factor of 90.05 are achieved. Moreover, a maximum rms error in retrieved values of dielectric constant and loss tangent of liquid under test is found to be 1.092% and 0.813%, respectively. Our demonstrated EBG-based sensor has a compact footprint with good precision, affordability, and ease of operation in detecting liquids for microwave sensing applications.
16 citations
References
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TL;DR: In this article, a metamaterial-inspired microwave microfluidic sensor is proposed, where the main part of the device is a microstrip coupled complementary split-ring resonator (CSRR), and the liquid sample flowing inside the channel modifies the resonance frequency and peak attenuation of the CSRR resonance.
Abstract: A new metamaterial-inspired microwave microfluidic sensor is proposed in this paper. The main part of the device is a microstrip coupled complementary split-ring resonator (CSRR). At resonance, a strong electric field will be established along the sides of CSRR producing a very sensitive area to a change in the nearby dielectric material. A micro-channel is positioned over this area for microfluidic sensing. The liquid sample flowing inside the channel modifies the resonance frequency and peak attenuation of the CSRR resonance. The dielectric properties of the liquid sample can be estimated by establishing an empirical relation between the resonance characteristics and the sample complex permittivity. The designed microfluidic sensor requires a very small amount of sample for testing since the cross-sectional area of the sensing channel is over five orders of magnitude smaller than the square of the wavelength. The proposed microfluidic sensing concept is compatible with lab-on-a-chip platforms owing to its compactness.
527 citations
TL;DR: In this paper, a microwave resonator is presented as a microfabricated sensor dedicated to liquid characterization with perspectives for chemistry and biology, where the nanolitter range aqueous solution under investigation is located on top of the planar resonator thanks to a microfluidic channel compatible with a future lab-on-a-chip integration.
Abstract: A microwave resonator is presented as a microfabricated sensor dedicated to liquid characterization with perspectives for chemistry and biology. The nanolitter range aqueous solution under investigation is located on top of the planar resonator thanks to a microfluidic channel compatible with a future lab-on-a-chip integration. The interaction between the electric field and the liquid translates into a predictable relationship between electrical characteristics of the resonator (resonant frequency and associated insertion loss) and the complex permittivity of the fluid (real and imaginary parts). A prototype of the resonator has been fabricated and evaluated with de-ionized water/ethanol mixtures with ethanol volume fraction ranging from 0% to 20%. Good agreement has been reached between theoretical and measured electrical parameters of the resonator. The discrepancy on the resonant frequency is estimated to 0.5%, whereas the one on the associated transmission coefficient is lower than 1%. This translates into a maximum relative error on the real and imaginary part of the predicted relative permittivity of less than 6.5% and 4%, respectively, validating the principle of this accurate permittivity characterization methodology.
269 citations
01 Jan 2012
TL;DR: In this paper, the results of a recent program of dielectric reference liquid measurements at National Physical Laboratory (NPL) are presented over a range of temperatures (in most cases at 5o intervals in the range 10 - 50 oC).
Abstract: This report summarises the results of a recent programme of dielectric reference liquid measurements at National Physical Laboratory (NPL). It is intended that full details of the methods of measurement will be published in the scientific literature in the near future. Comprehensive tables of dielectric relaxation parameters for high purity methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, dimethyl sulphoxide and ethanediol are presented over a range of temperatures (in most cases at 5o intervals in the range 10 - 50 oC). These were derived from measurements at NPL between the years 1997 and 2000 at frequencies extending up to 5 GHz. The relaxation parameters are generally those of the single or double Debye models, which are found to offer a good fit to the measured data in nearly all cases. In addition, static permittivity data are presented for pure water, acetone, silicone oil and cyclohexane. All of the data presented is traceable to UK National Standards. Advisory notes on the use of the tables are provided.
249 citations
01 Jan 1990
197 citations
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29 Oct 2017
TL;DR: In this article, the transmission/reflection and short-circuit line methods for measuring complex permittivity were examined and robust algorithms that eliminate the illbehaved nature of the commonly used transmission/reflect method a t frequencies corresponding to integral multiples of one-half wavelength in the sample are presented.
Abstract: The transmission/reflection and short-circuit line methods for measuring complex permittivity are examined. Equations for permittivity are developed from first principles. New robust algorithms that eliminate the illbehaved nature of the commonly used transmission/reflection method a t frequencies corresponding to integral multiples of one-half wavelength in the sample are presented. These allow measurements to be made on samples of any length. An uncertainty analysis is presented which yields estimates of the errors incurred due to the uncertainty in scattering parameters, length measurement and reference plane position. The equations derived here indicate that the minimum uncertainty for transmission/reflection measurements of nonmagnetic materials occurs a t integral multiples of one-half wavelength in the material. In addition, new equations for determining complex permittivity independent of reference plane position and sample length are derived. New equations are derived for permittivity determination using the short-circuit line allow positioning the sample arbitrarily in the sample holder.
183 citations