scholarly journals Electromagnetic characteristics of materials based on ultrafine hexaferrite powders

2021 ◽  
Vol 1198 (1) ◽  
pp. 012005
Author(s):  
YuN Gladkov ◽  
AS Kachalov ◽  
EYu Korovyn ◽  
AA Pavlova
Keyword(s):  
Composite Materials ◽  
Dielectric Permittivity ◽  
Frequency Dependence ◽  
Mechanical Treatment ◽  
Wide Band ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
Frequency Range ◽  
Nanosized Powders ◽  
Electromagnetic Characteristics

Abstract The electromagnetic characteristics of composite materials based on nanosized powders of W-type hexaferrites are considered in the article. It is shown that not only the composition, but also the mechanical treatment affects the electromagnetic parameters. This article presents the frequency dependence of the complex magnetic and dielectric permittivity of a system of W-type hexafferites. The studies were carried out on a universal wide-band measuring complex based on the Agilent PNA-X N4257A Vector Network Analyzer. The results are presented in the frequency range from 2 to 14 GHz.

Combined vector network analyzer and impedance analyzer for broadband determination of complex permittivity spectrum of glass beads with talc

2020 ◽  
Author(s):  
Justyna Szerement ◽  
Hironobu Saito ◽  
Kahori Furuhata ◽  
Shin Yagihara ◽  
Agnieszka Szypłowska ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Dielectric Permittivity ◽  
Glass Beads ◽  
Vector Network Analyzer ◽  
Complex Dielectric Permittivity ◽  
Network Analyzer ◽  
Frequency Range ◽  
Impedance Analyzer ◽  
Permittivity Spectrum

<p>Soil complex dielectric permittivity is frequency dependent. At low frequencies soil dielectric spectrum exhibits relaxation effects mainly due to interfacial phenomena caused by water strongly bounded to solid phase particles surfaces, double-layer effects and Maxwell-Wagner effect. At frequencies of several GHz and above, the influence of dielectric dispersion of free water dipoles can be observed.  Since dielectric soil moisture meters operate at frequencies from kHz up to several GHz, their output can be affected by these phenomena.</p><p>Currently, there is a variety of commercial sensors that operate at various frequencies from kHz up to several GHz. Most popular are TDR sensors with frequency band up to 1-2 GHz and capacitance/impedance sensors that operate at a single frequency usually from the range <br>1-150 MHz. Therefore, the knowledge of the broadband complex dielectric permittivity spectrum can help to improve the existing and develop new methods and devices for soil moisture and salinity estimation. Also, accurate characterization of complex dielectric permittivity spectrum of porous materials in the broadband frequency range is required for modeling of dielectric properties of materials in terms of moisture, salinity, density, mineralogy etc.</p><p>The aim of the study was to measure the complex dielectric permittivity of glass beads with 5% talc moistened with distilled water and saline water (electrical conductivity of 500, 1000, 1500 mS/m). The experiment was carried out using a seven-rod probe connected to an impedance analyzer (IA) and a vector network analyzer (VNA) using a multiplexer in the frequency range from 40Hz to 110MHz (IA) and 10MHz to 500MHz (VNA). The glass beads (90-106 µm, Fuji Manufacturing Industries, Japan) with 5% talc (Sigma Aldrich) in 4 different moisture and 4 different salinity values were examined. The results obtained from the IA and the VNA were combined and modeled with complex conductivity and dielectric permittivity model. The influence of water content and electrical conductivity on broadband complex dielectric spectra and the fitted model parameters was examined.</p><p> </p><p>The work has been supported by the National Centre for Research and Development, Poland, BIOSTRATEG3/343547/8/NCBR/2017.</p>

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.

scholarly journals A Novel Wineglass Shaped Wide Band Antenna for TV White Space Communication

2018 ◽  
Vol 7 (4.5) ◽  
pp. 324
Author(s):  
Ghulam Ahmad Raza ◽  
Garima Saini ◽  
Naveen Kumar
Keyword(s):  
Patch Antenna ◽  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
White Space ◽  
Good Match ◽  
Space Communication ◽  
Tv White Space

This paper presents a novel patch antenna for TV white spaces applications. The shape of the proposed antenna is based on the shape of a wineglass. The dimension of the proposed antenna is 170 mm x 120 mm x 1.6 mm. After simulation, the proposed antenna resonates at 703 MHz with a return loss of -21.97 dB and covering a bandwidth from 495 MHz to 1540 MHz. Overall bandwidth coverage is 1045 MHz. So the proposed antenna is a wide band antenna covering almost the entire TV Ultra High Frequency (UHF) range. Simulated VSWR obtained at 703 MHz is 1.38 dB and simulated gain is 2.32 dB. The proposed antenna is fabricated using FR4 substrate and tested on Vector Network Analyzer (VNA). The measured return loss of fabricated antenna is -20.20 dB at 596 MHz. Proposed antenna shows the simulated radiation efficiency of 95%. Simulated and measured results showed good match between them. Proposed design is compared with few designs available in literature to validate its novelty and advantages. 

scholarly journals Методика измерения потерь в направляемых линиях передачи в миллиметровом диапазоне частот

2022 ◽  
Vol 48 (5) ◽  
pp. 36
Author(s):  
Н.С. Князев ◽  
А.И. Малкин ◽  
В.А. Чечеткин
Keyword(s):  
Experimental Method ◽  
Transmission Lines ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
Frequency Range ◽  
Scattering Matrices ◽  
Coplanar Transmission Lines

An experimental method was developed to determine losses in microstrip and coplanar transmission lines for devices operating in the frequency range 77 - 81 GHz. The parameters of the scattering matrices are obtained using a vector network analyzer and frequency upconverters. The calculation of losses in waveguide-coplanar and coplanar-microstrip junctions is made.

Sub-Surface Microwave Imaging Using Four-Slot Vivaldi Antenna with Improved Directivity

Frequenz ◽  
2017 ◽  
Vol 71 (1-2) ◽  
pp. 19-28 ◽  
Author(s):  
Zubair Akhter ◽  
Pankaj Kumar ◽  
M. Jaleel Akhtar
Keyword(s):  
Return Loss ◽  
Wide Band ◽  
Point Of View ◽  
Ultra Wide Band ◽  
Network Analyzer ◽  
Frequency Range ◽  
Radiation Characteristics ◽  
Rf Components ◽  
Vivaldi Antenna ◽  
Good Agreement

Abstract The conventional tapered slot Vivaldi antenna is well known for its ultra-wide band characteristics with low directivity. To improve the directivity of the conventional Vivaldi antenna, a four-slot Vivaldi antenna (FSVA) is proposed here to operate in the frequency range of 2–11 GHz. For feeding the FSVA, a binomial three-section V-shaped even mode power divider with progressing T-junctions is also designed and tested here, which is then integrated with the antenna. The proposed antenna prototype is designed and fabricated on a 1-mm thick FR-4 substrate (ɛr=4.3, tanδ=0.025), and the return loss and radiation characteristics are investigated in the anechoic environment. The measured result shows a good agreement with the numerical simulation performed using the EM Simulator i. e. CST MWS-2015. It is found that the directivity of FSVA is approximately doubled as compared to that of the conventional Vivaldi antenna having the same dimensions. From the application point of view, the fabricated antenna is used to image various metallic objects hidden inside the sand using a vector network analyzer and associated RF components. The obtained 2D microwave images of the test media successfully show that the hidden objects can effectively be located and detected using the proposed FSVA in conjunction with a simple imaging scheme.

scholarly journals Electromagnetic response from multilayer composite coatings based on carbonyl iron, ferroelectrics and MWCNTs at microwave

2019 ◽  
Vol 30 ◽  
pp. 07011
Author(s):  
Grigoriy E. Kuleshov ◽  
Alexey V. Sbrodov ◽  
Tatyana N. Shematilo
Keyword(s):  
Experimental Study ◽  
Composite Materials ◽  
Carbonyl Iron ◽  
Composite Coatings ◽  
Dielectric Constants ◽  
Electromagnetic Response ◽  
Multilayer Composite ◽  
Frequency Range ◽  
Electromagnetic Characteristics ◽  
Frequency Dependences

The electromagnetic characteristics of composite materials based on carbonyl iron, ferroelectrics, and MWCNTs were studied in this article. The complex magnetic and dielectric constants of the experimental samples were measured in the frequency range from 1 GHz to 18 GHz. The results of calculation and the experimental study of the frequency dependences of the reflection coefficient on a multilayer composite coating located on a reflective surface are presented.

Complex Dielectric Permittivity of Sandy Loam as a Function of Salinity and Biomass at Microwaves

2013 ◽  
Vol 209 ◽  
pp. 116-120 ◽  
Author(s):  
Arun Sharma ◽  
K.C. Pancholi ◽  
S.P. Bhatnagar
Keyword(s):  
Soil Moisture ◽  
Dielectric Permittivity ◽  
Sandy Loam ◽  
Strong Dependence ◽  
Normal Incidence ◽  
Complex Dielectric Permittivity ◽  
Network Analyzer ◽  
Frequency Range ◽  
Moisture Contents ◽  
Loam Soil

Real and Imaginary parts of Complex Dielectric Permittivity (ε’ and ε” ) of Sandy Loam soil have been measured in the frequency range 150 MHz – 2.4 GHz using a Vector Network Analyzer at varied Moisture contents, Salinity and Biomass. The Emissivity of the soil for normal incidence was also calculated from measured values of Complex Permittivity. The measured permittivity data show strong dependence on moisture content. Salinity causes higher permittivity and dielectric loss. Biomass appears to enhance the permittivity data due to increase in porosity of the soil. The emissivity of the soil was observed to decrease with increasing soil moisture and soil salinity, but it increases with biomass.

scholarly journals Dielectric Properties of Glass Beads with Talc as a Reference Material for Calibration and Verification of Dielectric Methods and Devices for Measuring Soil Moisture

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1968 ◽  
Author(s):  
Justyna Szerement ◽  
Hironobu Saito ◽  
Kahori Furuhata ◽  
Shin Yagihara ◽  
Agnieszka Szypłowska ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Reference Material ◽  
Dielectric Permittivity ◽  
Open Water ◽  
Glass Beads ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
Calibration Curves ◽  
Salinity Index ◽  
Calibration And Verification

This paper presents dielectric measurements of talc, glass beads, and their mixtures under different moisture and salinity levels. The measurements were conducted using a prototype seven-rod probe (15 mm long central rod) connected to a single port of vector network analyzer. The samples were moistened with distilled water and KCl solutions in order to obtain six different moisture content levels. The complex dielectric permittivity was determined from vector network analyzer reflection-coefficient measurements based on the open-water-liquid calibration procedure. Next, the fitting of volumetric water content–real part of dielectric permittivity calibration curves was performed for each material at selected frequencies, and the obtained relations were compared with well-known calibration equations. Additionally, a salinity index for the tested materials was calculated. It was concluded that pure talc is not an optimal material for the calibration and verification of dielectric methods. The calibration curves obtained for glass beads and the mixtures of glass beads with talc gave results close to well-known reference calibration functions. Additionally, the addition of talc caused the data points to be less scattered. Moreover, the values of the salinity index for the tested materials were in a good agreement with literature data for sand. The obtained results indicated that glass beads with the addition of talc can be used as a reference material for the calibration and verification of dielectric methods and devices for soil moisture measurement.

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.

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