scholarly journals Extremely Sensitive Microwave Microfluidic Dielectric Sensor Using a Transmission Line Loaded with Shunt LC Resonators

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6811
Author(s):  
Haneen Abdelwahab ◽  
Amir Ebrahimi ◽  
Francisco J. Tovar-Lopez ◽  
Grzegorz Beziuk ◽  
Kamran Ghorbani
Keyword(s):  
Electric Field ◽  
Transmission Line ◽  
Microfluidic Channel ◽  
High Sensitivity ◽  
Sensor Performance ◽  
Methanol Solutions ◽  
Dielectric Sensor ◽  
Lc Resonator ◽  
Working Principle ◽  
Lc Resonators

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.

scholarly journals Microwave Differential Frequency Splitting Sensor Using Magnetic-LC Resonators

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1066 ◽  
Author(s):  
Amir Ebrahimi ◽  
Grzegorz Beziuk ◽  
James Scott ◽  
Kamran Ghorbani
Keyword(s):  
Dielectric Properties ◽  
Transmission Line ◽  
Reference Sample ◽  
Solid Materials ◽  
Microstrip Transmission Line ◽  
Frequency Splitting ◽  
Metallic Wall ◽  
Lc Resonator ◽  
Lc Resonators

A differential microwave permittivity sensor and comparator is designed using a microstrip transmission line loaded with a magnetic-LC resonator. The microstrip transmission line is aligned with the electric wall of the resonator. The sensor shows a single transmission zero, when it is unloaded or loaded symmetrically on both halves. A second notch appears in the transmission response by asymmetrical dielectric loading on the two halves of the device. The frequency splitting is used to characterize the dielectric properties of the samples under test. The sensitivity of the sensor is enhanced by removing the mutual coupling between the two halves of the magnetic-LC resonator using a metallic wall. The sensors’ operation principle is explained through a circuit model analysis. A prototype of the designed sensor is fabricated and measurements are used for validation of the sensing concept. The sensor can be used for determination of the dielectric properties in solid materials or detecting defects and impurities in solid materials through a comparative measurement with a reference sample.

scholarly journals Sensing Electrochemical Signals Using a Nitrogen-Vacancy Center in Diamond

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 358
Author(s):  
Hossein T. Dinani ◽  
Enrique Muñoz ◽  
Jeronimo R. Maze
Keyword(s):  
Electric Field ◽  
Electron Spin ◽  
Electrolyte Solution ◽  
High Sensitivity ◽  
Theoretical Work ◽  
Coherence Time ◽  
Nitrogen Vacancy ◽  
Local Concentration ◽  
Concentration Of Ions ◽  
Nv Center

Chemical sensors with high sensitivity that can be used under extreme conditions and can be miniaturized are of high interest in science and industry. The nitrogen-vacancy (NV) center in diamond is an ideal candidate as a nanosensor due to the long coherence time of its electron spin and its optical accessibility. In this theoretical work, we propose the use of an NV center to detect electrochemical signals emerging from an electrolyte solution, thus obtaining a concentration sensor. For this purpose, we propose the use of the inhomogeneous dephasing rate of the electron spin of the NV center (1/T2★) as a signal. We show that for a range of mean ionic concentrations in the bulk of the electrolyte solution, the electric field fluctuations produced by the diffusional fluctuations in the local concentration of ions result in dephasing rates that can be inferred from free induction decay measurements. Moreover, we show that for a range of concentrations, the electric field generated at the position of the NV center can be used to estimate the concentration of ions.

Fast Aptamer Generation Method Based on the Electrodynamic Microfluidic Channel and Evaluation of Aptamer Sensor Performance

2020 ◽  
Author(s):  
Saeromi Chung ◽  
Nanjanagudu Ganesh Gurudatt ◽  
Jinsung Jeon ◽  
Changill Ban ◽  
Yoon-Bo Shim
Keyword(s):  
Microfluidic Channel ◽  
Sensor Performance ◽  
Aptamer Sensor

Mechanism of Cell Lysis in Microfluidic Channel With Integrated Nanocomposite Electrodes

2013 ◽  
Author(s):  
Madhusmita Mishra ◽  
Anil Krishna Koduri ◽  
Aman Chandra ◽  
D. Roy Mahapatra ◽  
G. M. Hegde
Keyword(s):  
Electric Field ◽  
Microfluidic Channel ◽  
Cell Lysis ◽  
Bacterial Cells ◽  
Nano Composite ◽  
Time Resolved ◽  
Ac Electric Field ◽  
Cell Dispersion ◽  
Electrical Lysis ◽  
Nanocomposite Electrodes

This paper reports on the characterization of an integrated micro-fluidic platform for controlled electrical lysis of biological cells and subsequent extraction of intracellular biomolecules. The proposed methodology is capable of high throughput electrical cell lysis facilitated by nano-composite coated electrodes. The nano-composites are synthesized using Carbon Nanotube and ZnO nanorod dispersion in polymer. Bacterial cells are used to demonstrate the lysis performance of these nanocomposite electrodes. Investigation of electrical lysis in the microchannel is carried out under different parameters, one with continuous DC application and the other under DC biased AC electric field. Lysis in DC field is dependent on optimal field strength and governed by the cell type. By introducing the AC electrical field, the electrokinetics is controlled to prevent cell clogging in the micro-channel and ensure uniform cell dispersion and lysis. Lysis mechanism is analyzed with time-resolved fluorescence imaging which reveal the time scale of electrical lysis and explain the dynamic behavior of GFP-expressing E. coli cells under the electric field induced by nanocomposite electrodes. The DNA and protein samples extracted after lysis are compared with those obtained from a conventional chemical lysis method by using a UV–Visible spectroscopy and fluorimetry. The paper also focuses on the mechanistic understanding of the nano-composite coating material and the film thickness on the leakage charge densities which lead to differential lysis efficiency.

60-Hertz Electric-Field Exposures in Transmission Line Towers

2005 ◽  
Vol 2 (9) ◽  
pp. 444-455 ◽  
Author(s):  
T. Bracken ◽  
Russell Senior ◽  
Joseph Dudman
Keyword(s):  
Electric Field ◽  
Transmission Line

scholarly journals A High-Sensitivity Microfluidic Sensor Based on a Substrate Integrated Waveguide Re-Entrant Cavity for Complex Permittivity Measurement of Liquids

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4005 ◽  
Author(s):  
Zhihua Wei ◽  
Jie Huang ◽  
Jing Li ◽  
Guoqing Xu ◽  
Zongde Ju ◽  
...  
Keyword(s):  
Predictive Model ◽  
Complex Permittivity ◽  
Perturbation Technique ◽  
Microfluidic Channel ◽  
High Sensitivity ◽  
Substrate Integrated Waveguide ◽  
Debye Relaxation ◽  
Permittivity Measurement ◽  
Acetone Water ◽  
Complex Permittivity Measurement

In this study, a novel non-invasive and contactless microwave sensor using a square substrate integrated waveguide (SIW) re-entrant cavity is proposed for complex permittivity measurement of chemical solutions. The working principle of this sensor is based on cavity perturbation technique, in which the resonant properties of cavity are utilized as signatures to extract the dielectric information of liquid under test (LUT). A winding microfluidic channel is designed and embedded in the gap region of the cavity to obtain a strong interaction between the induced electric field and LUT, thus achieving a high sensitivity. Also, a mathematical predictive model which quantitatively associates the resonant properties of the sensor with the dielectric constant of LUT is developed through numerical analysis. Using this predictive model, quick and accurate extraction of the complex permittivity of LUT can be easily realized. The performance of this sensor is then experimentally validated by four pure chemicals (hexane, ethyl acetate, DMSO and water) together with a set of acetone/water mixtures in various concentrations. Experimental results demonstrate that the designed sensor is capable of characterizing the complex permittivities of various liquids with an accuracy of higher than 96.76% (compared with the theoretical values obtained by Debye relaxation equations), and it is also available for quantifying the concentration ratio of a given binary mixture.

Sign in / Sign up

Export Citation Format

Share Document