scholarly journals Investigation of the parameters of the reflected wave near the Brewster angle

2021 ◽  
Vol 2140 (1) ◽  
pp. 012026
Author(s):  
V P Krylov
Keyword(s):  
Electromagnetic Waves ◽  
Dielectric Material ◽  
Angular Position ◽  
Experimental Studies ◽  
Dielectric Materials ◽  
Brewster Angle ◽  
Magnetic Losses ◽  
Geometric Optics ◽  
Phase Jump ◽  
Reflected Wave

Abstract In free space, the relative permittivity is determined by the Brewster formula without taking into account dielectric and magnetic losses. In experimental studies, discrepancies in the angular position of the minimum of the reflected wave from dielectric materials are observed in comparison with calculations, which are known as deviations from Fresnel’s laws. By solving the task of inclined falling wave on an plate made of a dielectric material with complex of the dielectric and magnetic permittivity, the parameters of the reflected wave were calculated, according to which the angles corresponding to the minimum reflection were determined, depending on the dielectric losses of the material. From the condition that the reflected wave is equal to zero, a formula for determining the Brewster angle for a material with dielectric and magnetic losses was analytically obtained, the results of calculations for which coincided with the calculations for the reflected wave in the context of geometric optics. It is determined that in the general case, the conditions for determining the position of the minimum of the complex amplitude and the phase jump by 180° of electromagnetic waves do not coincide and can be found only when solving the task an falling wave on a plate with complex electrodynamic parameters of the material in the context of geometric optics.

Determination of the Brewster angle of the wave reflected from a plate with dielectric losses

2021 ◽  
Vol 87 (11) ◽  
pp. 39-42
Author(s):  
V. P. Krylov ◽  
A. E. Zhitelev
Keyword(s):  
Dielectric Material ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Classical Problem ◽  
Dielectric Materials ◽  
Field Vector ◽  
Calculation Model ◽  
Brewster Angle ◽  
Dielectric Losses ◽  
Reflected Wave

In free space, the permittivity of materials is usually determined by the value of the Brewster angle using the angular dependences of the amplitude and phase of the wave reflected from the material plate. An expression corresponding to materials without dielectric and magnetic losses is used as a calculation model. Experimental studies of the parameters of the wave reflected from dielectric materials show the discrepancies with theoretical calculations known as deviations from the Fresnel laws. We present the results of determining the Brewster angle of the wave reflected from a plate made of a material with dielectric losses. The angular dependences of the amplitude and phase of the reflected wave were calculated using the numerical solution of the problem of falling at an arbitrary angle of a plane linearly polarized wave with an electric field vector lying in the plane of incidence on a plate of a dielectric material with complex values of the dielectric and magnetic permittivity. They were used to determine the angles corresponding to the minimum reflection coefficient depending on the dielectric losses of the plate material. The differences between the numerical calculations and the data obtained using the Brewster angle formula were noted, which increased with increasing dielectric losses of the material. From the condition that the modulus of the reflected wave amplitude is equal to zero, a different formula for calculating the Brewster angle for a material with losses is analytically obtained. The results of calculations using this formula coincided with the calculations for the reflected wave when solving the classical problem of the inclined incidence of a plane wave on a plate of a dielectric material in the framework of geometric optics. The results obtained can be used to determine the Brewster angle for a wave reflected from a plate with magnetic and dielectric losses.

Automatic defect recognition for pulsed terahertz inspection of basalt fiber reinforced composites

2016 ◽  
Vol 35 (4) ◽  
pp. 1346-1359 ◽  
Author(s):  
Przemyslaw Lopato
Keyword(s):  
Electromagnetic Waves ◽  
Dielectric Material ◽  
Conductive Polymer ◽  
Basalt Fiber ◽  
Principal Component ◽  
Dielectric Materials ◽  
Fiber Reinforced ◽  
Content Type ◽  
Non Destructive Evaluation ◽  
Non Destructive

Purpose – The purpose of this paper is to present a system for automatic recognition of defects detected in non-conductive polymer composites using pulsed terahertz imaging. Design/methodology/approach – On the beginning, non-destructive evaluation of composites using electromagnetic waves in terahertz frequency is shortly introduced. Next automatic defects recognition (ADR) algorithm is proposed, focussing on new features calculation. Dimensionality of features space is reduced by using principal component analysis. Finally, results of basalt fiber reinforced composite materials inspection and identification using artificial neural networks is presented and discussed. Findings – It is possible to develop ADR system for non-destructive evaluation of dielectric materials using pulsed terahertz technique. New set of features in time and frequency domains is proposed and verified. Originality/value – ADR in non-destructive testing is utilized in case of digital radiography and ultrasonic testing. Terahertz inspection with pulsed excitation is reported as a source of many useful information about the internal structure of the dielectric material. Up to now ADR based on terahertz non-destructive evaluation systems was not utilized.

Evaluation of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings by the multi-frequency radio wave method of a slow surface electromagnetic waves

2020 ◽  
pp. 51-58
Author(s):  
Aleksandr I. Kazmin ◽  
Pavel A. Fedjunin
Keyword(s):  
Radio Wave ◽  
Noise Level ◽  
Electromagnetic Waves ◽  
Dielectric Materials ◽  
Geometric Parameters ◽  
Experimental Investigations ◽  
Wave Method ◽  
Dielectric Coatings ◽  
Surface Electromagnetic Waves ◽  
Multilayer Dielectric

One of the most important diagnostic problems multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the checkout results their electrophysical and geometric parameters. The results of a study of the potential informativeness of the multi-frequency radio wave method of surface electromagnetic waves during reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings are presented. The simulation model is presented that makes it possible to evaluate of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings. The model takes into account the values of the electrophysical and geometric parameters of the coating, the noise level in the measurement data and the measurement bandwidth. The results of simulation and experimental investigations of reconstruction of the structure of relative permittivitties and thicknesses of single-layer and double-layer dielectric coatings with different thicknesses, with different values of the standard deviation (RMS) of the noise level in the measured attenuation coefficients of the surface slow electromagnetic wave are presented. Coatings based on the following materials were investigated: polymethyl methacrylate, F-4D PTFE, RO3010. The accuracy of reconstruction of the electrophysical parameters of the layers decreases with an increase in the number of evaluated parameters and an increase in the noise level. The accuracy of the estimates of the electrophysical parameters of the layers also decreases with a decrease in their relative permittivity and thickness. The results of experimental studies confirm the adequacy of the developed simulation model. The presented model allows for a specific measuring complex that implements the multi-frequency radio wave method of surface electromagnetic waves, to quantify the potential possibilities for the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric materials and coatings. Experimental investigations and simulation results of a multilayer dielectric coating demonstrated the theoretical capabilities gained relative error permittivity and thickness of the individual layers with relative error not greater than 10 %, with a measurement bandwidth of 1 GHz and RMS of noise level 0,003–0,004.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

Assessment of Power Consumption of an Electrodynamic Dust Shield to Clean Solar Panels

2016 ◽  
Author(s):  
Jennifer K. W. Chesnutt ◽  
Bing Guo ◽  
Chang-Yu Wu
Keyword(s):  
Power Consumption ◽  
Dielectric Material ◽  
Average Power ◽  
Experimental Studies ◽  
Particle Interactions ◽  
Solar Panels ◽  
Particle Collisions ◽  
Monodisperse Particles ◽  
Power Requirement ◽  
Transport Distance

Substantial time and money have been directed toward photovoltaic solar power. However, mitigation of dust on solar panels has been largely neglected. The objective of this research was to determine the performance and power consumption of an electrodynamic dust shield (EDS) to clean solar panels as a function of dust particle size. We utilized a discrete element method to computationally simulate the transport, collision, and electrodynamic interactions of particles subjected to electrodynamic waves generated by an EDS. The EDS consisted of electrodes embedded within a dielectric material. 1250 monodisperse particles with diameters of 30–50 μm were simulated. In the absence of particle-particle interactions, an increase in diameter increased particle transport distance due to increased particle charge. However, inclusion of particle-particle collisions produced interactions such that an intermediate diameter yielded the smallest transport distance. Average power required to lift a particle off the surface was smallest with the smallest particle; however, power requirement decreased with diameter with a constant loading of particles on the EDS. Calculated from our simulation data, power consumption per unit area of an experimental EDS agreed with previous experimental studies. Our study elucidated important aspects of EDS operation and power consumption to mitigate dust on solar panels.

NONRECIPROCAL ELECTROMAGNETIC DEVICES IN GYROMAGNETIC PHOTONIC CRYSTALS

2013 ◽  
Vol 28 (02) ◽  
pp. 1441010 ◽  
Author(s):  
ZHI-YUAN LI ◽  
RONG-JUAN LIU ◽  
LIN GAN ◽  
JIN-XIN FU ◽  
JIN LIAN
Keyword(s):  
Magnetic Field ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Experimental Studies ◽  
Magnetic Surface ◽  
Electromagnetic Properties ◽  
Edge States ◽  
Bragg Scattering ◽  
Electromagnetic Devices ◽  
Gap Opening

Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing.

Influence of the Microstructure of Cutting Ceramics on the Efficiency of the Machining Process

2021 ◽  
Vol 1040 ◽  
pp. 21-27
Author(s):  
Aleksei D. Khalimonenko ◽  
E.G. Zlotnikov ◽  
Ilya V. Gorshkov ◽  
M.A. Popov
Keyword(s):  
Electrical Resistance ◽  
Dielectric Material ◽  
Experimental Studies ◽  
Tool Material ◽  
Test Sample ◽  
Machining Process ◽  
Ceramic Plate ◽  
Conductive Material ◽  
Microstructural Parameters ◽  
Cutting Ceramics

The article deals with the determination of the efficiency of a multi-bladed tool equipped with inserts made of oxide-carbide cutting ceramics, depending on the microstructural parameters of the tool material. The microstructural parameters of the oxide-carbide cutting ceramic, which affect the performance of the tool, are proposed to be determined according to the electrical resistance of the tool material. In order to implement the method for determining the working capacity of the instrument, a basic design of the device for measuring the electrical resistance of the material of the instrument is proposed. The device for measuring the electrical resistance of ceramic plates consists of a body made of a dielectric material, with channels for supplying a conductive material and a groove for installing a case with a test sample. During the test, the channels are filled with a liquid conductive material, which fills the cavity formed by the channel of the case, the groove of the case and the plate itself under test. To ensure uniform filling of the cavity, after the introduction of the liquid conductive material, metal balls are installed into the channels, which are made in such a size as to ensure free sliding along the channel, but not to let the liquid pass into the upper part of the channel. The tested ceramic plate is installed in the walls of the removable case. The walls of the removable case include electrodes, which, when the device is in operation, are inserted into a cavity with a liquid conductive material at one end, and are connected to an ohmmeter at the other. Using a device for measuring the electrical resistance of ceramic plates, it is possible to determine the operability of the tool and guarantee its operation without rejection for a certain period of time, which was confirmed by experimental research in the milling of workpieces of machine parts made of gray cast iron. Experimental studies in multi-edge machining with cutters with different values ​​of electrical resistance of ceramic plates made it possible to plot graphs of the dependence of the quality of machining during milling on the operability of the tool and on the time of the machining process.

Low Temperature Curing - Aqueous Base Developable Photoimageable Dielectric for WLP (Wafer Level Packaging)

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000986-001015
Author(s):  
Eric Huenger ◽  
Joe Lachowski ◽  
Greg Prokopowicz ◽  
Ray Thibault ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Low Temperature ◽  
Dielectric Material ◽  
Broad Band ◽  
Dielectric Materials ◽  
Next Generation ◽  
Wafer Level ◽  
Moore’S Law ◽  
Moore's Law ◽  
3D Chip Stacking ◽  
The Impact

As advanced packaging application space evolves and continues to deviate from the conventional shrinkage pathway predicted by Moore's law, material suppliers need to continue to work with OEMs, OSATs and Foundries to identify specific opportunities. One such opportunity continues to present itself in developing new materials to support new platforms for next generation products to support 3D chip stacking and TSV applications. The newer material sets can be established to meet more challenging design requirements associated with the demands, presented by the application from both a physical/lithographical processing and design perspective. Next generation packages requires the development of new dielectric materials that can support both the physical demands of 3D chip stacking and TSV package design aspects while maintaining strengths of the existing material platform. While vertical integration necessitates the use of thinned substrates and its associated integration challenges, there is a continuing need to support horizontal shrinkage typical of the Moore's Law, which pushes the lithography envelope requiring finer pitch and smaller feature resolution capability. This presentation identifies the strategy we have taken and highlights approach taking in the development of low temperature curable photoimageable dielectric materials with enhanced lithographic performance. We will discuss the methodology used to create benzocyclobutene based dielectric material curable at 180 °C and show how lithographic performance can be tuned to allow sub 5 micron via using broad band illumination. Finally we will review the impact of low temperature processing on the mechanical, thermal and electrical properties of this novel photoimageable dielectric material.

Electrically Tunable Phase Shifters With Air-Dielectric Sandwich Structure

2002 ◽  
Vol 720 ◽  
Author(s):  
Minki Jeong ◽  
Victor Kazmirenko ◽  
Yuriy Poplavko ◽  
Beomjin Kim ◽  
Sunggi Baik
Keyword(s):  
Sandwich Structure ◽  
Phase Shifter ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Air Gap ◽  
Phase Shifters ◽  
Effective Dielectric Constant ◽  
Microwave Phase Shifter ◽  
Piezoelectric Control ◽  
Total Structure

AbstractElectrically tunable microwave phase shifter was developed by inserting dielectric slab and piezoelectric actuator inside a waveguide. Air-dielectric sandwich structure of dielectric material and thin air gap was placed inside a waveguide, where the thickness of air gap is controlled by the actuator. Small changes in the ratio between the thickness of dielectric material and air gap induce significant changes in the effective dielectric constant of the air-dielectric sandwich structure. Phase shifts of 20∼200 degrees were realized with the dielectric materials such as (Mg, Ca)TiO3 while the thickness of air gap is changed between 0 to 30 μm by piezoelectric control. Since the dielectric ceramics has very small loss (tand ∼ 10-4) and the air gap has practically no loss, the total structure shows low insertion loss.

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