Microwave Microfluidic Sensor for Detection of High Equol Concentrations in Aqueous Solution

Loutchanwoot, Panida; Harnsoongnoen, Supakorn

doi:10.1109/tbcas.2022.3153459

Cited by 16 publications

(10 citation statements)

References 59 publications

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“…Regarding the methods used in this study for modifying the operating frequency and electric field intensity of the microwave sensor, the C and CR values were modified in the equivalent circuit depicted in Figure 1b by etching copper into the middle of the CSRR and narrowing the slot into the position used for sample measurement. Although the number and centered fractional pattern within the CSRR structure have been partially studied [50][51][52][53][54], the square width of CSRR, the etched square size area in the middle of the ground plane inside CSRR, and the varying fractal geometry centered within the CSRR structure have not been studied and analyzed. In order to determine the optimal size and structure before fabricating the actual parts for E2 measurements, we conducted a simulation to determine the optimal square width of CSRR, etched square size area, and fractal geometry within the ground plane of CSRR.…”

Section: Sensor Designmentioning

confidence: 99%

“…Table 1 displays the geometrical parameters of the PF-NSCSRR device. The narrow slot width was located along the CSRR's lower edge, and the size and fractal count of the Peano fractal were centered within the CSRR structure [50][51][52][53][54]. Figure 1b shows the equivalent circuit model demonstration of the proposed sensor; L is the inductance of the transmission line per unit length, C is the coupling capacitance between the microstrip line and the CSRR structure, and C R and L R are the capacitance and inductance of the CSRR, respectively.…”

Section: Sensor Designmentioning

confidence: 99%

“…Although the number and centered fractional pattern within the CSRR structure have been partially studied [50][51][52][53][54], the square width of CSRR, the etched square size area in the middle of the ground plane inside CSRR, and the varying fractal geometry centered within the CSRR structure have not been studied and analyzed. In order to determine the optimal size and structure before fabricating the actual parts for E2 measurements, we conducted a simulation to determine the optimal square width of CSRR, etched square size area, and fractal geometry within the ground plane of CSRR.…”

Section: Sensor Designmentioning

confidence: 99%

“…The simulation results of the designed sensors are shown in Figure 5a. The CSRR at the F r of 2.355 GHz has a maximum electric field of 116.8 kV/m [40], the narrow square-shaped CSRR (NSSCSRR) at the F r of 2.357 GHz has a maximum electric field of 150.8 kV/m, the narrow slot CSRR (NSCSRR) at the F r of 2.256 GHz has a maximum electric field of 135.3 kV/m [46], the Peano fractal geometry with CSRR (PF-CSRR) at the F r of 2.374 GHz has a maximum electric field of 110 kV/m [51], and the PF-NSCSRR at the F r of 2.279 GHz has a maximum electric field of 139 kV/m. These results indicate that the NSSCSRR structure provided the highest electric field while the NSCSRR provided the lowest F r .…”

Section: Sensor Designmentioning

confidence: 99%

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Sensing High 17β-Estradiol Concentrations Using a Planar Microwave Sensor Integrated with a Microfluidic Channel

2023

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The global issue of pollution caused by endocrine-disrupting chemicals (EDCs) has been gaining increasing attention. Among the EDCs of environmental concern, 17β-estradiol (E2) can produce the strongest estrogenic effects when it enters the organism exogenously through various routes and has the potential to cause harm, including malfunctions of the endocrine system and development of growth and reproductive disorders in humans and animals. Additionally, in humans, supraphysiological levels of E2 have been associated with a range of E2-dependent disorders and cancers. To ensure environmental safety and prevent potential risks of E2 to human and animal health, it is crucial to develop rapid, sensitive, low cost and simple approaches for detecting E2 contamination in the environment. A planar microwave sensor for E2 sensing is presented based on the integration of a microstrip transmission line (TL) loaded with a Peano fractal geometry with a narrow slot complementary split-ring resonator (PF-NSCSRR) and a microfluidic channel. The proposed technique offers a wide linear range for detecting E2, ranging from 0.001 to 10 mM, and can achieve high sensitivity with small sample volumes and simple operation methods. The proposed microwave sensor was validated through simulations and empirical measurements within a frequency range of 0.5–3.5 GHz. The E2 solution was delivered to the sensitive area of the sensor device via a microfluidic polydimethylsiloxane (PDMS) channel with an area of 2.7 mm2 and sample value of 1.37 µL and measured by a proposed sensor. The injection of E2 into the channel resulted in changes in the transmission coefficient (S21) and resonance frequency (Fr), which can be used as an indicator of E2 levels in solution. The maximum quality factor of 114.89 and the maximum sensitivity based on S21 and Fr at a concentration of 0.01 mM were 1746.98 dB/mM and 40 GHz/mM, respectively. Upon comparing the proposed sensor with the original Peano fractal geometry with complementary split-ring (PF-CSRR) sensors without a narrow slot, several parameters were evaluated, including sensitivity, quality factor, operating frequency, active area, and sample volume. The results showed that the proposed sensor exhibited an increased sensitivity of 6.08% and had a 40.72% higher quality factor, while the operating frequency, active area, and sample volume showed decreases of 1.71%, 25%, and 28.27%, respectively. The materials under tests (MUTs) were analyzed and categorized into groups using principal component analysis (PCA) with a K-mean clustering algorithm. The proposed E2 sensor has a compact size and simple structure that can be easily fabricated with low-cost materials. With the small sample volume requirement, fast measurement with a wide dynamic range, and a simple protocol, this proposed sensor can also be applied to measure high E2 levels in environmental, human, and animal samples.

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Section: Sensor Designmentioning

confidence: 99%

Section: Sensor Designmentioning

confidence: 99%

Section: Sensor Designmentioning

confidence: 99%

Section: Sensor Designmentioning

confidence: 99%

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Sensing High 17β-Estradiol Concentrations Using a Planar Microwave Sensor Integrated with a Microfluidic Channel

2023

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“…The complementary split-ring resonator (CSRR) with the Peano fractal geometry-loaded microstrip line has served as the foundation for the sensor structure's design. The proposed sensor has been discovered to identify the sample type as well as the equol concentration range [18]. A planar microstrip SRR-based sensor with an active feedback loop has been designed in [19] for organic vapour sensing applications.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Based Electrochemical Sensor Design by SRR Approach for ISM Sensing Applications

et al. 2022

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This paper presents a transmission line and a split ring resonator (SRR) based sensor structure with a high sensitivity capacity to discriminate various methanol mixtures. The height of the dielectric layer and thickness of copper are assigned as 1.6 mm and 0.035 mm, respectively. The overall dimensions of the sensor structure are defined as 16 mm × 16 mm × 1.6 mm . The operating frequency is selected for the ISM bands, especially around 2.45 GHz. Different methanol-water mixtures are prepared at various ratios, and then, the complex permittivity values are measured. Different sensor structures are modelled and investigated using a two-port transmission line approach. Various types of SRR based sensors are designed, and an optimum design is proposed for methanol mixture detection applications. The observed quality factor of the proposed sensor is 16.5. The resonance shifts of the transmission value ( S 21 ) are used for sensing capability around 2.45 GHz at -45 dB and 90 MHz resonance shifts. The sensitivity of the sensor has been evaluated as 1 MHz. Finally, the electric field distributions of the proposed SRR integrated transmission line are investigated. The novelty of the proposed design is to exactly sense the ratio of methanol in water with a very simple design. The proposed sensor structure can be used for methanol detection applications in medical, military, and chemical research.

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High sensitivity detection of ethanol solution based on waveguide resonant cavity combined with metamaterials

Zhang,

Xu,

Chen

et al. 2024

Measurement

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Microwave Microfluidic Sensor for Detection of High Equol Concentrations in Aqueous Solution

Cited by 16 publications

References 59 publications

Sensing High 17β-Estradiol Concentrations Using a Planar Microwave Sensor Integrated with a Microfluidic Channel

Sensing High 17β-Estradiol Concentrations Using a Planar Microwave Sensor Integrated with a Microfluidic Channel

Microwave-Based Electrochemical Sensor Design by SRR Approach for ISM Sensing Applications

High sensitivity detection of ethanol solution based on waveguide resonant cavity combined with metamaterials

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