scholarly journals Sub-THz Characterisation of Monolayer Graphene

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ehsan Dadrasnia ◽  
Sujitha Puthukodan ◽  
Vinod V. K. Thalakkatukalathil ◽  
Horacio Lamela ◽  
Guillaume Ducournau ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Dynamic Range ◽  
Monolayer Graphene ◽  
Network Analyzer ◽  
Electrical Characteristics ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Wave Measurement ◽  
Direct Measurements

We explore the optical and electrical characteristics of monolayer graphene by using pulsed optoelectronic terahertz time-domain spectroscopy in the frequency range of 325–500 GHz based on fast direct measurements of phase and amplitude. We also show that these parameters can, however, be measured with higher resolution using a free space continuous wave measurement technique associated with a vector network analyzer that offers a good dynamic range. All the scattering parameters (both magnitude and phase) are measured simultaneously. The Nicholson-Ross-Weir method is implemented to extract the monolayer graphene parameters at the aforementioned frequency range.

scholarly journals Optoelectronic frequency-modulated continuous-wave terahertz spectroscopy with 4 THz bandwidth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lars Liebermeister ◽  
Simon Nellen ◽  
Robert B. Kohlhaas ◽  
Sebastian Lauck ◽  
Milan Deumer ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Terahertz Spectroscopy ◽  
Beat Signal ◽  
Photonic Integration ◽  
Terahertz Time Domain Spectroscopy ◽  
Destructive Testing ◽  
Optical Delay ◽  
Broadband Terahertz

AbstractBroadband terahertz spectroscopy enables many promising applications in science and industry alike. However, the complexity of existing terahertz systems has as yet prevented the breakthrough of this technology. In particular, established terahertz time-domain spectroscopy (TDS) schemes rely on complex femtosecond lasers and optical delay lines. Here, we present a method for optoelectronic, frequency-modulated continuous-wave (FMCW) terahertz sensing, which is a powerful tool for broadband spectroscopy and industrial non-destructive testing. In our method, a frequency-swept optical beat signal generates the terahertz field, which is then coherently detected by photomixing, employing a time-delayed copy of the same beat signal. Consequently, the receiver current is inherently phase-modulated without additional modulator. Owing to this technique, our broadband terahertz spectrometer performs (200 Hz measurement rate, or 4 THz bandwidth and 117 dB peak dynamic range with averaging) comparably to state-of-the-art terahertz-TDS systems, yet with significantly reduced complexity. Thickness measurements of multilayer dielectric samples with layer-thicknesses down to 23 µm show its potential for real-world applications. Within only 0.2 s measurement time, an uncertainty of less than 2 % is achieved, the highest accuracy reported with continuous-wave terahertz spectroscopy. Hence, the optoelectronic FMCW approach paves the way towards broadband and compact terahertz spectrometers that combine fiber optics and photonic integration technologies.

scholarly journals Miniaturized Coplanar Waveguide for Nanostructured Magnetostrictive Multilayer Characterization

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 851
Author(s):  
Abdelhatif El Fellahi ◽  
Aurélien Mazzamurro ◽  
Jean Claude Gerbedoen ◽  
Yannick Dusch ◽  
Olivier Bou Matar ◽  
...  
Keyword(s):  
Coplanar Waveguide ◽  
Complex Permeability ◽  
Network Analyzer ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Electromagnetic Simulations ◽  
Insertion Losses ◽  
The Magnetic Field ◽  
Large Frequency ◽  
Permeability Spectrum

A miniaturized coplanar waveguide (CPW) on a Y-cut LiNbO3 substrate operating in Radio Frequency region (RF) is proposed for studying of magnetostrictive multi-layered structure. The structure is composed of a 14 × [TbCo2 (3.7 nm)/FeCo (4 nm)] nanostructured multi-layer. Using microtechnology process, the miniaturized CPW has been designed with a 50 µm wide signal line in the frequency range from 6 MHz to 6 GHz. Electromagnetic simulations based on ®Ansys/HFSS demonstrate insertion losses less than 2 dB and show that the magnetic field is more confined in the nanostructured multi-layer placed on top of the micro-sized CPW. By using Vectorial Network Analyzer (VNA) the Ferromagnetic Resonance (FMR) is investigated from the reflection (Sii) or transmission (Sij) coefficients of scattering parameters. An inversion model is finally used to extract the complex permeability spectrum of the thin-film in a large frequency range.

scholarly journals A 10 kHz to 6 GHz Low-Cost Vector Network Analyzer

2021 ◽  
Vol 19 ◽  
pp. 17-22
Author(s):  
Andreas Depold ◽  
Stefan Erhardt ◽  
Robert Weigel ◽  
Fabian Lurz
Keyword(s):  
Dynamic Range ◽  
Low Cost ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
Frequency Range ◽  
Network Analyzers ◽  
Commercial Off The Shelf ◽  
Large Frequency ◽  
Cost Vector

Abstract. This publication introduces a low-cost vector network analyzer with very large frequency range made of commercial off-the-shelf components. It utilizes two identical receivers and two directional bridges to allow for two fully bidirectional measurement ports. The design surpasses the performance of competing low-cost network analyzers in regards of dynamic range, frequency span and calibration capability.

CW (Continuous Wave) Measurement System. Operating Manual

1982 ◽  
Author(s):  
J. E. Bridge ◽  
IV. Burns ◽  
Gagliano J. ◽  
Reinman G. A. ◽  
R. B.
Keyword(s):  
Measurement System ◽  
Continuous Wave ◽  
Wave Measurement ◽  
System Operating

scholarly journals Simulation and Experimental Study of the Near Field Probe in the Form of a Folded Dipole for Measuring Glucose Concentration

2021 ◽  
Vol 11 (12) ◽  
pp. 5415
Author(s):  
Aleksandr Gorst ◽  
Kseniya Zavyalova ◽  
Aleksandr Mironchev ◽  
Andrey Zapasnoy ◽  
Andrey Klokov
Keyword(s):  
Experimental Measurement ◽  
Glucose Concentration ◽  
Field Experiments ◽  
Near Field ◽  
Vector Network Analyzer ◽  
Human Hand ◽  
Physical Parameters ◽  
Network Analyzer ◽  
Frequency Range ◽  
Average Deviation

The article investigates the near-field probe of a special design to account for changes in glucose concentration. The probe is designed in such a way that it emits radiation in both directions from its plane. In this paper, it was proposed to modernize this design and consider the unidirectional emission of the probe in order to maximize the signal and reduce energy loss. We have done extensive research for both bidirectional and unidirectional probe designs. Numerical simulations and field experiments were carried out to determine different concentrations of glucose (0, 4, 5.3, 7.5 mmol/L). Numerical modeling of a unidirectional probe showed that the interaction of radiation generated by such a probe with a multilayer structure simulating a human hand showed a better result and high sensitivity compared to a bidirectional probe. Further, based on the simulation results, a phantom (physical model) of a human hand was recreated from layers with dielectric properties as close as possible to the properties of materials during simulation. The probe was constructed from a copper tube and matched both the geometric and physical parameters of the model. The experimental measurement was carried out using a vector network analyzer in the frequency range 2–10 GHz. The experimental measurement was carried out using a vector network analyzer in the frequency range 2–10 GHz for the unidirectional and bidirectional probes. Further, the results of the experiment were compared with the results of numerical simulation. According to the results of multiple experiments, it was found that the average deviation between the concentrations was 2 dB for a unidirectional probe and 0.4 dB for a bidirectional probe. Thus, the sensitivity of the unidirectional probe was 1.5 dB/(mmol/L) for the bidirectional one 0.3 dB/(mmol/L). Thus, the improved design of the near-field probe can be used to record glucose concentrations.

Mechanical and Microwave Dielectric Properties of Csf/Si3N4 Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1661-1664
Author(s):  
Xiao Yan Wang ◽  
Fa Luo ◽  
Dong Mei Zhu ◽  
Wan Cheng Zhou ◽  
Hong Huan Wu
Keyword(s):  
Carbon Fibers ◽  
Microwave Dielectric Properties ◽  
Xrd Analysis ◽  
Network Analyzer ◽  
Hot Press ◽  
Frequency Range ◽  
The Real ◽  
Microwave Dielectric ◽  
Hot Press Sintering ◽  
Sintering Method

Csf/Si3N4 composites were prepared by hot-press sintering method using α-Si3N4 power, short chopping carbon-fiber and sintering additives. XRD analysis showed that the α-Si3N4 was almost completely transferred into β-Si3N4. The SEM micrographs of fractured surfaces showed that special network developed by rod-like β- Si3N4 grains. The flexure strength of 590±10MPa, and fracture toughness of 7.94±0.1MPa·m1/2 were achieved for the samples incorporated with 0.5wt% the carbon fibers .The microwave dielectric property of Csf/Si3N4 composites was measured at a frequency range of 8.2~18GHz by E8362B PNA series network analyzer. The real part (ε ′ ) of the permittivity of the Csf/Si3N4 composites increases from 10 to 58 with the rise of the content of carbon fibers in the composites, as well as the imaginary part increases from 0.03 to 98 at frequency of 9.375GHz. A strong frequency dependence of the real part was observed both in X and Ku bands.

ELECTRICAL IMMUNITY CHARACTERISTICS OF MULTI-PAIR LAN CABLES

2021 ◽  
Author(s):  
И.С. ШЕРСТНИКОВ ◽  
В.В. СМИРНОВА ◽  
В.Б. ПОПОВ
Keyword(s):  
Noise Immunity ◽  
Experimental Studies ◽  
Electrical Characteristics ◽  
Frequency Range ◽  
Protective Polymer

Приводятся результаты экспериментальных исследованийпомехозащищенности цепей многопарных LAN-кабелей вдиапазоне частот до 100 МГц Показано, что разработанный комплекс мероприятий по технологии скрутки кабельного сердечника, наложению на него экрана и защитной полимерной оболочки позволяет обеспечить выполнение норм на электрические характеристики помехозащищенности цепей кабеля, отвечающих требованиям категории 5е. The results of experimental studies of noise immunity of multipair LAN-cable circuits in the frequency range up to 100 MHz are presented. It is shown that the developed set of measures for the technology of twisting the cable core and applying a screen and a protective polymer sheath on it made it possible to ensure compliance with the standards for the electrical characteristics of noise immunity of cable circuits that meet the requirements of category 5e.

scholarly journals Optical Properties of Crystalline Lactose Fluidized with Dilutions of Various Substances in the Terahertz Frequency Range

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 32
Author(s):  
Anna Baranova ◽  
Anastasiya Lykina ◽  
Daria Antonova ◽  
Olga Smolyanskaya
Keyword(s):  
Optical Properties ◽  
Interferon Gamma ◽  
Fluidized Beds ◽  
Principal Component ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Terahertz Frequency Range ◽  
Glycine Buffer ◽  
Diluted Solution

Lactose is a commonly used component of pharmaceutical medications in tablet form. It was previously shown that lactose changes conformationally after saturation in fluidized beds with active pharmaceutical ingredients obtained by repeated dilution of antibodies to interferon-gamma in combination with an external intensive vibration treatment. Moreover, it was revealed that these solutions are self-organized dispersed systems in which nano-objects are formed. Their biological activity and mechanism of action were previously established as well. The current work was dedicated to investigating the optical properties of fluidized lactose powders in the terahertz frequency range. Spectral analyses of powders of crystalline lactose saturated in fluidized beds with a diluted solution of either glycine buffer, antibodies to interferon-gamma, or water were carried out, intact lactose served as a control. All powders were tableted before testing. In the course of the study, the macroscopic parameters of the tablets were established, at which they had a stable shape and their THz optical properties had no parasitic diffraction losses. These tablets were analyzed using terahertz time-domain spectroscopy in the frequency range of 0.2–2.6 THz. The differentiation between the spectra was conducted using a principal component analysis. The differences between intact lactose and the lactose saturated with any of studied solutions were demonstrated. Additionally, lactose saturated with solutions of multiple dilutions of a substance (antibodies or glycine buffer) differed not only from intact lactose, but also from lactose saturated with a diluted solution of water. Moreover, discrimination of lactose formulations saturated with different substances (antibodies or glycine buffer) was also possible. Additionally, intact lactose differed from lactose saturated with diluted water. The methods reported could be useful for the quality control of the medications based on the technology of repeated dilution of an original substance.

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