Application of a SAR procedure for the determination of dielectric constants in free space

2008 ◽  
Author(s):  
M. Anis ◽  
A. Jostingmeier ◽  
A.S. Omar
Keyword(s):  
Free Space ◽  
Dielectric Constants

Determination of the velocity of short electromagnetic waves by interferometry

1952 ◽  
Vol 213 (1112) ◽  
pp. 123-141 ◽  
Keyword(s):  
Phase Velocity ◽  
Electromagnetic Radiation ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Wave Beam ◽  
Wave Length ◽  
Wave Frequency ◽  
Space Wave

A new measurement of the velocity of electromagnetic radiation is described. The result has been obtained, using micro-waves at a frequency of 24005 Mc/s ( λ = 1∙25 cm), with a form of interferometer which enables the free-space wave-length to be evaluated. Since the micro-wave frequency can also be ascertained, phase velocity is calculated from the product of frequency and wave-length. The most important aspect of the experiment is the application to the measured wave-length of a correction which arises from diffraction of the micro-wave beam. This correction is new to interferometry and is discussed in detail. The result obtained for the velocity, reduced to vacuum conditions, is c 0 = 299792∙6 ± 0∙7 km/s.

scholarly journals Soft Nondamaging Contacts Formed from Eutectic Ga–In for the Accurate Determination of Dielectric Constants of Organic Materials

2018 ◽  
Vol 30 (16) ◽  
pp. 5527-5533 ◽  
Author(s):  
Evgenia Douvogianni ◽  
Xinkai Qiu ◽  
Li Qiu ◽  
Fatemeh Jahani ◽  
Floris B. Kooistra ◽  
...  
Keyword(s):  
Organic Materials ◽  
Accurate Determination ◽  
Dielectric Constants

scholarly journals On the measurement of the dielectric constants of liquids, with a determination of the dielectric constant of benzene

1929 ◽  
Vol 123 (792) ◽  
pp. 664-685 ◽  
Keyword(s):  
Dielectric Constant ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Experimental Conditions ◽  
The Past ◽  
A Value ◽  
The Subject ◽  
Important Indication

It has long been recognised that the dielectric constant of a substance gives an important indication of its constitution, and the classical papers of Nernst and Drude giving methods for the determination of dielectric constants, have been followed by a long series of papers giving the dielectric constants of several hundreds of pure liquids and solutions. Since the publication of Debye’s dipole theory in 1912, the literature of the subject has become even more voluminous than before. In surveying the mass of data one is struck by the very large discrepancies which exist in the values obtained by different observers for any one substance, and it is very difficult to decide whether they are due to the difficulty of pre­paring and purifying the substance, differences in experimental conditions such as frequency of the applied E. M. F., or errors in the methods of measure­ment. In order to make it possible to compare the results of different observers, and to provide a fundamental basis for new measurements, it is important that the value of at least one standard liquid should be known with unquestion­able accuracy. The object of the present investigation was to provide such a value. Benzene was chosen as the standard liquid since it has been very widely used in the past, and it is used as a standard in the measurement of other physical properties.

Determination of the Site Occupancy of Holmium in SrTiO3 by Alchemi

1998 ◽  
Vol 4 (S2) ◽  
pp. 582-583
Author(s):  
S. C. Cheng ◽  
A. Hitomi ◽  
C. A. Randall
Keyword(s):  
Site Occupancy ◽  
Dielectric Constants ◽  
Reducing Atmosphere ◽  
Copper Electrodes ◽  
The Face ◽  
Face Centered ◽  
High Dielectric ◽  
A Site ◽  
The Ideal

The perovskite structure is based upon the mineral CaTiO3, which is a pseadocubic at room temperature. The ideal structure has a twelve fold coordinate A-site, and an octahedral coordinated B-site, and the face-centered position being oxygen. The perovskites have been of commercial interest for capacitors owing to their high dielectric constants. The crystal chemistry related to the perovskite based dielectrics multilayer capacitors (MLCs) is of interest in this paper. The MLCs with base metal internal electrodes such as copper and nickel have been studied for many years. To avoid oxidation of the nickel or copper electrodes during sintering, a reducing atmosphere is necessary. However, reduced firing causes two basic problems: an increasing of conductivity of the BaTiO3, dielectrics and limitation on reliability by the migration of oxygen vacancies. The solution for the first problem is to use acceptor dopants, such as MnO and more stable oxide additives, such as CaZrO3 to increase the resistivity of the dielectrics.

scholarly journals Eigenmode analysis of the electromagnetic field scattered by an elliptic cone

2011 ◽  
Vol 9 ◽  
pp. 31-37 ◽  
Author(s):  
M. Kijowski ◽  
L. Klinkenbusch
Keyword(s):  
Free Space ◽  
Plane Electromagnetic Wave ◽  
Multipole Expansion ◽  
Neumann Condition ◽  
Electrically Conducting ◽  
Eigenmode Analysis ◽  
Elliptic Cone ◽  
Series Transformation ◽  
Neumann Eigenvalues

Abstract. The vector spherical-multipole analysis is applied to determine the scattering of a plane electromagnetic wave by a perfectly electrically conducting (PEC) semi-infinite elliptic cone. From the eigenfunction expansion of the total field in the space outside the elliptic cone, the scattered far field is obtained as a multipole expansion of the free-space type by a single integration over the induced surface currents. As for the evaluation of the free-space-type expansion it is necessary to apply suitable series transformation techniques, a sufficient number of eigenfunctions has to be considered. The eigenvalues of the underlying two-parametric eigenvalue problem with two coupled Lamé equations belong to the Dirichlet- or the Neumann condition and can be arranged as so-called eigenvalue curves. It has been observed that the eigenvalues are in two different domains: In the first one Dirichlet- and Neumann eigenvalues are either nearly coinciding, while in the second one they are strictly separated. The eigenfunctions of the first (coinciding) type look very similar to free-space modes and do not contribute to the scattered field. This observation allows to significantly improve the determination of diffraction coefficients.

scholarly journals On the direct determination of the electrostatic moments of molecules

1929 ◽  
Vol 124 (795) ◽  
pp. 689-698 ◽  
Keyword(s):  
Dielectric Constant ◽  
Direct Determination ◽  
Negative Temperature ◽  
Dielectric Constants ◽  
Temperature Coefficients ◽  
Different Temperatures

According to Faraday's ideas, the specific inductive capacity of a substance is due to the polarisation of the molecules as wholes. This is the basis of the old Clausius-Mosotti theory of dielectrics, on which it is shown first that the polarisation P is proportional to the polarising field, i. e. , P = k E, k being the dielectric constant, and second that δ being the density of the dielectric, k - 2/ k + 2 ·1/δ = constant. Now it is known that some substances have large negative temperature coefficients for their dielectric constants which cannot thus be accounted for. To provide for this Debye proposed the theory that the molecules were permanently polarised and that they were systematically orientated in the field. This leads to the equation k - 2/ k + 2 = a T -1 + b T -2 , to represent the change of specific inductive capacity with temperature. This theory has been developed by Gans and others, and a number of measurements have been made by Smyth and others, who have found the molecular moments of many substances by measuring the dielectric constants at different temperatures.

A Method for Reducing the Effect of Surface Contamination Layers in Reflection Diagnostics of Graphene-like 2D Materials

NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850044 ◽  
Author(s):  
Peep Adamson
Keyword(s):  
2D Materials ◽  
Dielectric Constants ◽  
Angle Of Incidence ◽  
Method Error ◽  
Long Wavelength ◽  
Long Wavelength Approximation ◽  
Wavelength Approximation ◽  
Reflectance Measurements ◽  
Effect Of Surface

The values of the published dielectric constants of graphene determined on the basis of optical diagnostics methods differ significantly from each other. This is due, in particular, to contaminating layers on the surface of graphene or between the substrate and the graphene layer, the parameters of which are not generally known and which, therefore, are difficult to take into account. In this work, it is shown how to integrate ellipsometric and reflectance measurements so that the influence of contaminating layers on the determination of dielectric constants of graphene-like 2D materials is minimal or practically absent at all. The inversion problem is solved analytically within the long-wavelength approximation. The equations for determining the dielectric constants of graphene have only one definite solution and do not need the knowledge of the initial guesses. A thorough analysis has been made of the dependence of the method error on the parameters of the structure under study, the wavelength and angle of incidence of optical radiation.

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