Sectorial substrate-integrated half-mode near-field sensors for biological liquid characterization

2014 ◽  
Vol 6 (3-4) ◽  
pp. 305-312 ◽  
Author(s):  
Nora Meyne ◽  
Arne F. Jacob
Keyword(s):  
Factor Analysis ◽  
Perturbation Theory ◽  
Aqueous Solutions ◽  
Quality Factor ◽  
Near Field ◽  
Calibration Method ◽  
Biological Liquid ◽  
Suitable Reference ◽  
5 Ghz

Two compact resonant near-field sensors are introduced for the characterization of aqueous solutions at 5 GHz. They are based on folded substrate-integrate circular half-mode resonators with a planar sensing tip. Owing to the planar design, the sensor is simple and cheap to manufacture, and a sample can be easily coupled to the resonator from the top. The operating principle of the sensor is explained and verified by both simulation and measurement. The radiation of the sensors is quantified by means of a quality factor analysis. Finally, a previously introduced calibration method based on the perturbation theory is applied to the sensors and its accuracy is improved by choosing more suitable reference materials.

A 5 GHz Resonant Cavity for Complex Permittivity Measurements: Design, Test Performances and Application

2006 ◽  
Vol 514-516 ◽  
pp. 1561-1565 ◽  
Author(s):  
Luís Cadillon Costa ◽  
Susana Devesa ◽  
François Henry
Keyword(s):  
Perturbation Theory ◽  
Quality Factor ◽  
Small Perturbation ◽  
Complex Permittivity ◽  
Resonant Cavity ◽  
Cavity Resonator ◽  
Finite Conductivity ◽  
Theoretical Treatment ◽  
Resonance Frequencies ◽  
5 Ghz

The theoretical treatment of a cavity resonator consists of solving the Maxwell equations in that cavity, respecting the boundary conditions. The resonance frequencies appear as conditions in the solutions of the differential equation involved and are not significantly affected by the fact that the cavity walls have a finite conductivity. Solutions for rectangular cavities and for the lowest resonant mode, where the probability of mistaking one mode from another is slight, are readily obtained. The measurement of the complex permittivity, ε* = ε´-iε´´, can be made using the small perturbation theory. In this method, the resonance peak frequency and the quality factor of the cavity, with and without a sample, can be used to obtain the complex dielectric permittivity of the material. We measure the shift in the resonant frequency of the cavity, f, caused by the insertion of the sample, which can be related to the real part of the complex permitivitty, ε´, while the change in the inverse of the quality factor of the cavity, (1/Q), gives the imaginary part, ε´´. In this work we report the construction details, the performance tests of the cavity to confirm the possibility of the use of the small perturbation theory, and the application of the technique to measure the complex permittivity of a reinforced plastic.

Dielectric contrast measurements on biological substances with resonant microwave near-field sensors

2013 ◽  
Vol 5 (3) ◽  
pp. 221-230 ◽  
Author(s):  
Nora Haase ◽  
Arne F. Jacob
Keyword(s):  
Perturbation Theory ◽  
Complex Permittivity ◽  
Chinese Hamster Ovary ◽  
Culture Medium ◽  
Near Field ◽  
Chinese Hamster ◽  
Cell Suspensions ◽  
Resonant Frequencies ◽  
Dielectric Contrast

Resonant substrate integrated near-field sensors are used for characterization of aqueous solutions at three different frequencies. In addition, Chinese hamster ovary (CHO) cells in a culture medium are characterized with the same sensors. Different concentrations as well as different vital states of cell suspensions are examined. The complex permittivity of the samples is evaluated using a linearized method based on perturbation theory. The permittivity differences between the measured cell suspensions are discussed. The resonant frequencies of the sensors are close to 3, 7, and 11 GHz, respectively.

A fast LED calibration method under near field lighting based on photometric stereo

2021 ◽  
Vol 147 ◽  
pp. 106749
Author(s):  
Long Ma ◽  
Yuzhe Liu ◽  
Jirui Liu ◽  
Shengwei Guo ◽  
Xin Pei ◽  
...  
Keyword(s):  
Near Field ◽  
Calibration Method ◽  
Photometric Stereo

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

scholarly journals Coherent suppression of backscattering in optical microresonators

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Andreas Ø. Svela ◽  
Jonathan M. Silver ◽  
Leonardo Del Bino ◽  
Shuangyou Zhang ◽  
Michael T. M. Woodley ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bulk Material ◽  
Near Field ◽  
High Quality Factor ◽  
Dual Frequency ◽  
High Quality ◽  
Frequency Combs ◽  
Optical Microresonators ◽  
Whispering Gallery ◽  
The Stability

AbstractAs light propagates along a waveguide, a fraction of the field can be reflected by Rayleigh scatterers. In high-quality-factor whispering-gallery-mode microresonators, this intrinsic backscattering is primarily caused by either surface or bulk material imperfections. For several types of microresonator-based experiments and applications, minimal backscattering in the cavity is of critical importance, and thus, the ability to suppress backscattering is essential. We demonstrate that the introduction of an additional scatterer into the near field of a high-quality-factor microresonator can coherently suppress the amount of backscattering in the microresonator by more than 30 dB. The method relies on controlling the scatterer position such that the intrinsic and scatterer-induced backpropagating fields destructively interfere. This technique is useful in microresonator applications where backscattering is currently limiting the performance of devices, such as ring-laser gyroscopes and dual frequency combs, which both suffer from injection locking. Moreover, these findings are of interest for integrated photonic circuits in which back reflections could negatively impact the stability of laser sources or other components.

scholarly journals Visualization of microwave near-field distribution in sodium chloride and glucose aqueous solutions by a thermo-elastic optical indicator microscope

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhirayr Baghdasaryan ◽  
Arsen Babajanyan ◽  
Levon Odabashyan ◽  
Jung-Ha Lee ◽  
Barry Friedman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Field Distribution ◽  
Near Field ◽  
Absorption Properties ◽  
Novel Approach ◽  
Concentration Changes ◽  
Biological Liquids ◽  
Optical Indicator ◽  
Distribution Intensity

AbstractIn this study, a new optical method is presented to determine the concentrations of NaCl and glucose aqueous solutions by using a thermo-elastic optical indicator microscope. By measuring the microwave near-field distribution intensity, concentration changes of NaCl and glucose aqueous solutions were detected in the 0–100 mg/ml range, when exposed to microwave irradiation at 12 GHz frequency. Microwave near-field distribution intensity decreased as the NaCl or glucose concentration increased due to the changes of the absorption properties of aqueous solution. This method provides a novel approach for monitoring NaCl and glucose in biological liquids by using a CCD sensor capable of visualizing NaCl and glucose concentrations without scanning.

Sign in / Sign up

Export Citation Format

Share Document