scholarly journals Propiedades electromagnéticas de un compuesto magneto dieléctrico a través de un algoritmo basado en el método Nicolson-Ross-Weir

2021 ◽  
Vol 21 (1) ◽  
pp. 59-69
Author(s):  
Gabriel Peña Rodríguez ◽  
Rodrigo Vera Barrera ◽  
David Leonardo Mancipe Huérfano ◽  
Luis Ángel Lara González
Keyword(s):  
Absorption Coefficient ◽  
Transmission Line ◽  
High Frequency ◽  
Relative Permittivity ◽  
Polyester Resin ◽  
Measured Data ◽  
Polymeric Matrix ◽  
Best Response ◽  
Permittivity And Permeability ◽  
S Parameters

The present work implements the Nicolson-Ross-Weir (NRW) method to find the permittivity and permeability through an algorithm in Matlab® of a magneto - dielectric composed material made of polyester resin and magnetite powders randomly dispersed and oriented vertically and horizontally in the polymeric matrix. The measured data come from the simulation of the S parameters in ADS® between 150 kHz and 4GHz, on a microstrip type transmission line. The algorithm allowed to verify that the best response in high frequency of the magneto - dielectric composed where the vertically orientedparticles, present the highest relative permittivity obtaining Er= 5.5 for 30% wt concentration and Er= 4.5 concentration of 20% wt, with an absorption coefficient which increases in function of frequency and the concentration of magnetite in the functional filler.

Fabrication of graphene-magnetite multi-granule nanocluster composites for microwave absorption application

2019 ◽  
Vol 53 (28-30) ◽  
pp. 4097-4103
Author(s):  
Boo H An ◽  
Bum C Park ◽  
Hamad A Yassi ◽  
Ji S Lee ◽  
Jung-Rae Park ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Microwave Absorption ◽  
Free Space ◽  
Relative Permittivity ◽  
Horn Antennas ◽  
Microwave Absorbing Properties ◽  
X Band ◽  
Permittivity And Permeability ◽  
Free Space Method ◽  
Space Method

Ferrite multi-granule nanoclusters are fabricated for microwave absorption materials in different sized particles and granules by modified polyol process. Various sizes of ferrite nanoclusters are placed on graphene-based composites and the behavior of their microwave absorbing properties is studied. The absorbing properties are measured using the free-space method with two horn antennas for X-band range (8.2 GHz–12.4 GHz). Relative permittivity and permeability values are calculated in measured frequency domain. The absorption coefficient changes by forming ferrite-graphene composites are presented as well.

scholarly journals Couplinator: A simple computational tool for synthesis of multi-section coupled-line filter based on MPCM-TLM technique

2021 ◽  
pp. 1-10
Author(s):  
E. Faghand ◽  
S. Karimian ◽  
E. Mehrshahi ◽  
N. Karimian
Keyword(s):  
Comparative Analysis ◽  
Transmission Line ◽  
High Frequency ◽  
Computational Tool ◽  
Cad Tools ◽  
Coupled Line ◽  
High Frequency Structure Simulator ◽  
Transmission Line Method ◽  
Set Up ◽  
Planar Circuit

Abstract A new simple computational tool is proposed for the synthesis of multi-section coupled-line filters based on combined modified planar circuit method (MPCM) and transmission line method (TLM) analysis, referred to as MPCM-TLM. Due to its fundamentally simple architecture, the presented tool offers significantly faster optimization of coupled-line filters – for exactly the same initial simulation set-up – than other costly commercially-available tools, giving equally reliable results. Validity and accuracy of the proposed tool have been verified through the design of 3rd, 5th, and 7th order coupled-line filters and comparative analysis between results obtained from the proposed approach and the high-frequency structure simulator. A remarkable 99% time reduction in the analysis is recorded in the case of 7th order filter using the proposed tool, for almost identical results to HFSS. Therefore, it can be confidently claimed that the proposed technique can be used as a reliable alternative to existing complex, costly, processor-intensive CAD tools.

scholarly journals Parasitic Loop Inductances Reduction in the PCB Layout in GaN-Based Power Converters Using S-Parameters and EM Simulations

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1495
Author(s):  
Loris Pace ◽  
Nadir Idir ◽  
Thierry Duquesne ◽  
Jean-Claude De Jaeger
Keyword(s):  
High Frequency ◽  
Printed Circuit Board ◽  
Power Converters ◽  
Calibration Procedure ◽  
Circuit Board ◽  
Design System ◽  
Switching Speed ◽  
Parasitic Inductance ◽  
Frequency Converters ◽  
S Parameters

Due to the high switching speed of Gallium Nitride (GaN) transistors, parasitic inductances have significant impacts on power losses and electromagnetic interferences (EMI) in GaN-based power converters. Thus, the proper design of high-frequency converters in a simulation tool requires accurate electromagnetic (EM) modeling of the commutation loops. This work proposes an EM modeling of the parasitic inductance of a GaN-based commutation cell on a printed circuit board (PCB) using Advanced Design System (ADS®) software. Two different PCB designs of the commutation loop, lateral (single-sided) and vertical (double-sided) are characterized in terms of parasitic inductance contribution. An experimental approach based on S-parameters, the Cold FET technique and a specific calibration procedure is developed to obtain reference values for comparison with the proposed models. First, lateral and vertical PCB loop inductances are extracted. Then, the whole commutation loop inductances including the packaging of the GaN transistors are determined by developing an EM model of the device’s internal parasitic. The switching waveforms of the GaN transistors in a 1 MHz DC/DC converter are given for the different commutation loop designs. Finally, a discussion is proposed on the presented results and the development of advanced tools for high-frequency GaN-based power electronics design.

scholarly journals The absorption of hard monochromatic γ-radiation

1930 ◽  
Vol 128 (807) ◽  
pp. 345-359 ◽  
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Wave Length ◽  
Low Frequency ◽  
Photoelectric Effect ◽  
Fourth Power ◽  
X Rays ◽  
Photoelectric Absorption ◽  
Initial Direction ◽  
Γ Radiation

Energy may be removed from a beam of γ -rays traversing matter by two distinct mechanisms. A quantum of radiation may be scattered by an electron out of its initial direction with change of wave-length, or it may be absorbed completely by an atom and produce a photoelectron. The total absorption coefficient, μ, is defined by the equation d I/ dx = -μI, and is the sum of the coefficients σ and τ referring respectively to the scattering and to the photoelectric effect. For radiation of low frequency, such as X-rays, the photoelectric absorption is very much more important than the absorption due to scattering, and many experiments have shown that the photoelectric absorption per atom varies as the fourth power of the atomic number and approximately as the cube of the wave-length. For radiation of high frequency, such as the more penetrating γ -rays, the photoelectric effect is, even for the heavy elements, smaller than the scattering absorption; and, since the scattering from each electron is always assumed to be independent of the atom from which it is derived, it is most convenient to divide μ. defined above by the number of electrons per unit volume in the material and to obtain μ e the absorption coefficient per electron.

scholarly journals Kajian Eksperimental Koefisien Redaman Akustik Bahan Pelapis Plat Dek Kapal

2018 ◽  
Vol 3 (1) ◽  
pp. 41
Author(s):  
Wibowo Harso Nugroho ◽  
Nanang J.H. Purnomo ◽  
Hardi Zen ◽  
Andi Rahmadiansah
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Transmission Loss ◽  
Base Material ◽  
Sound Insulation ◽  
Insulation Material ◽  
Base Materials ◽  
Specimen Material ◽  
Ship Classification ◽  
Technical Assessment

With the increasingly strict requirements of the ship classification bureau for permissible noise limits to allow passengers and crew to be more comfortable and secure a technical assessment is required to address the characteristics of the noise. A noise beyond the standard allowed in the vessel can be a problem to the ship operators. This noise problem will greatly affects the crews' comfort and passengers. One method to reduce the noise on a ship is to use sound insulation. This paper describes the method for determining the absorption coefficient α and the transmission loss (TL) through an acoustic test of a concrete insulation in the laboratory. The test was conducted by using the method of impedance tube where a speciment response measured by a microphone. In general, the properties of this insulation material remains as the main base material which is concrete. it has been found that the transmission loss value (TL) is in the range of 10 - 50 dB whereas for the base material the concrete is around 22 - 49 dB but the absorption coefficient α of the specimen material is much higher than the material of the base material especially in high frequency, which ranges from 0.15 to 0.97, whereas for concrete base materials have absorbent coefficient α ranges from 0.01 to 0.02.

scholarly journals High frequency characteristics of a magnetically insulated transmission line oscillator oscillating in HEM11 mode

2008 ◽  
Vol 57 (8) ◽  
pp. 4875
Author(s):  
Wang Dong ◽  
Chen Dai-Bing ◽  
Fan Zhi-Kai ◽  
Deng Jing-Kang
Keyword(s):  
Transmission Line ◽  
High Frequency ◽  
Frequency Characteristics
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