Simulation of complex dielectric structures

1970 ◽  
Vol 48 (21) ◽  
pp. 2623-2628
Author(s):  
A. Fedotowsky ◽  
G. Boivin ◽  
A. K. Sen ◽  
R. Tremblay
Keyword(s):  
Dielectric Constant ◽  
Continuous Variation ◽  
Experimental Results ◽  
Microwave Scattering ◽  
Dielectric Structures

Methods for simulating dielectric targets having a continuous variation of the dielectric constant for microwave scattering purposes are described. Experimental results are also presented.

scholarly journals Characterization of percolation behavior in conductor–dielectric 0-3 composites

2014 ◽  
Vol 04 (04) ◽  
pp. 1450035 ◽  
Author(s):  
Lin Zhang ◽  
Patrick Bass ◽  
Zhi-Min Dang ◽  
Z.-Y. Cheng
Keyword(s):  
Dielectric Constant ◽  
Percolation Threshold ◽  
Frequency Dependence ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
Filler Concentration ◽  
Percolation Behavior ◽  
The Matrix ◽  
The Relationship

The equation ε eff ∝ (ϕc - ϕ)-s which shows the relationship between effective dielectric constant (εeff) and the filler concentration (φ), is widely used to determine the percolation behavior and obtain parameters, such as percolation threshold φc and the power constant s in conductor–dielectric composites (CDCs). Six different systems of CDCs were used to check the expression by fitting experimental results. It is found that the equation can fit the experimental results at any frequency. However, it is found that the fitting constants do not reflect the real percolation behavior of the composites. It is found that the dielectric constant is strongly dependent on the frequency, which is mainly due to the fact that the frequency dependence of the dielectric constant for the composites close to φc is almost independent of the matrix.

Comb Shaped Triple Band Microstrip Antenna for Wireless Communication

2021 ◽  
Vol 9 (4) ◽  
pp. 379-382
Keyword(s):  
Dielectric Constant ◽  
Wireless Communication ◽  
High Frequency ◽  
Microstrip Antenna ◽  
Return Loss ◽  
Experimental Results ◽  
High Frequency Structure Simulator ◽  
Frequency Structure ◽  
Triple Band

A comb shaped microstrip antenna is designed by loading rectangular slots on the patch of the antenna. The antenna resonating at three different frequencies f1 = 5.35 GHz, f2 = 6.19 GHz and f3= 8.15 GHz. The designed antenna is simulated on High Frequency Structure Simulator software [HFSS] and the antenna is fabricated using substrate glass epoxy with dielectric constant 4.4 having dimension of 8x4x0.16 cms. The antenna shows good return loss, bandwidth and VSWR. Experimental results are observed using Vector Analyzer MS2037C/2.

An Analytical Model for the Effective Dielectric Constant of a 0-3-0 Composite

2010 ◽  
Author(s):  
K. A. Cook-Chennault ◽  
S. Banerjee
Keyword(s):  
Dielectric Constant ◽  
Aspect Ratio ◽  
Analytical Model ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
The Third ◽  
Third Phase ◽  
Three Phase ◽  
Phase 0 ◽  
Experimental Values

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al [1]. We extend the analytical model, so that the influence of the shape of the third phase inclusion, on the effective dielectric constant of the composite, can be investigated. The results indicate that the dielectric constant increases ∼7 times, when the aspect ratio of the conductive inclusion is increased from 1 (sphere) to 10 (spheroid). The analytical predictions compare favorably with the experimental values.

Doppler Spectra of Microwave Backscatter From Water Surface

2004 ◽  
Author(s):  
Chang-Kyu Rheem ◽  
Hidetaka Kobayashi ◽  
Kazuomi Yamanishi
Keyword(s):  
Water Surface ◽  
Microwave Remote Sensing ◽  
Close Relation ◽  
Global Scale ◽  
Experimental Results ◽  
Sea Surface ◽  
Surface Measurement ◽  
Doppler Spectrum ◽  
Microwave Scattering ◽  
The Mean

This paper describes the experimental results of microwave backscattering at water surfaces. Active microwave remote sensing is one of the useful techniques for sea surface measurement. For example, it enables us to know the wind vector on global scale. A principle of measurement is that the microwave backscattering depends on the wind speed. Therefore understanding of the phenomena of microwave scattering at sea surface in detail is indispensable for improvement of measuring accuracy. The purpose of the research is to investigate the characteristics of microwave scattering at various water surface conditions. Water surface was generated by wind and currents, microwave backscattering at that surface was measured by X and C-band microwave scatterometer. The experimental results were summarized in scattering coefficients and Doppler spectra. X-band microwave was more sensitive at wind wave surface than C-band. The mean frequency of Doppler spectrum of backscattering microwave was corresponded to the phase velocity of the mean water surface wave and the bandwidth of Doppler spectrum had close relation to the orbital velocity of the mean wave. A current had no effect on the scattering coefficient, but the Doppler spectrum was shifted to the side corresponding to current direction.

ON THE STATIC DIELECTRIC CONSTANT OF DIPOLAR SOLIDS

1951 ◽  
Vol 29 (2) ◽  
pp. 163-173 ◽  
Author(s):  
J. H. Simpson
Keyword(s):  
Dielectric Constant ◽  
General Formula ◽  
Short Range ◽  
Nearest Neighbors ◽  
Experimental Results ◽  
Static Dielectric Constant ◽  
Sharp Transition ◽  
Qualitative Comparison ◽  
Dipolar Molecules ◽  
Range Type

An application of Fröhlich's general formula for the static dielectric constant is made to a material having a cubic arrangement of dipolar molecules, each of which has two equilibrium positions 180° apart and ordering forces of the short range type which tend to make nearest neighbors antiparallel. It is shown that such a model cannot lead to a sharp transition in dielectric constant unless changes in lattice dimensions occur. Qualitative comparison with certain experimental results is made.

In—Line Measurement Of High Temperature Dielectric Constant In The Process Of Sintering

1996 ◽  
Vol 430 ◽  
Author(s):  
Zhou Jian ◽  
Cheng Jiping ◽  
Tang Yuling ◽  
Qiu Jinyu
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Resonant Cavity ◽  
Ceramic Materials ◽  
Dielectric Constants ◽  
Experimental Results ◽  
Cavity Method ◽  
Experimental Basis ◽  
Ceramic Samples ◽  
Line Measurement

AbstractIn this paper, a resonant cavity method is developed and some experimental results for measuring dielectric constants of ceramic samples (e. g. Al2O3) under different sintering temperatures are reported. The experiments show that this method has higher precision and good prospects of in—line monitoring the high temperature dielectric constant in the process of raising the temperature of the samples. These results provide some scientific experimental basis for physical research of ceramic materials.

scholarly journals Mixing Formulae and Experimental Results for the Dielectric Constant of Snow

1985 ◽  
Vol 31 (108) ◽  
pp. 163-170 ◽  
Author(s):  
Ari Sihvola ◽  
Ebbe Nyfors ◽  
Martti Tiuri
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Liquid Water ◽  
Complex Permittivity ◽  
Experimental Results ◽  
Exponential Models ◽  
Dielectric Mixture ◽  
Excess Permittivity ◽  
Wet Snow ◽  
Mixture Theories

AbstractThis paper discusses dielectric properties of snow according to various dielectric models and compares them with experimental results. The complex permittivity of wet snow is assumed to consist of two parts, being the sum of the permittivity of dry snow (a mixture of ice and air) and the excess permittivity due to liquid water (resulting from the dielectric mixture of water and air). In particular the effect of liquid water is considered. Exponential models and structure-dependent models based on mixture theories by Taylor and Tinga and others are applied. It is shown that the assumption that water inclusions have the form of either randomly oriented discs or needles, or of spheres do, not get empirical confirmation but the inclusions are preferably prolate ellipsoids (ellipticity 0.16) or oblate ellipsoids (ellipticity 0.12), dry snow being a dielectric mixture of randomly oriented disc-shaped ice particles and air.

scholarly journals Micro-Structure Modelling and Electrical Properties Analysis of PZT Matrix Ferroelectric Composites

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 448 ◽  
Author(s):  
Weibin Zhou ◽  
Jinbo Fan ◽  
Zhenchao Xin ◽  
Guodong You
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Random Access ◽  
Volume Ratio ◽  
Experimental Results ◽  
The Real ◽  
High Dielectric Permittivity ◽  
Important Research Topic ◽  
Microstructure Model ◽  
High Dielectric

PZT matrix ferroelectric composite is an important research topic in material science because of its many practical, industrial, and scientific applications. Materials with high dielectric permittivity are used to manufacture electronic devices, particularly capacitors and dynamic random access memory (DRAM). Therefore, the development of reliable and efficient micro models to be utilized in analyzing electrical properties can be of great value in accelerating research in this field. In this paper, a 3D microstructure model for PZT matrix ferroelectric composites has been developed and adopted the finite element method (FEM) to calculate the dielectric constant. The microscopy parameters of developed microstructure model are acquired based on the real composites from X-ray (micro-) diffraction and stereological method. The dielectric constant of different volume ratios of PZT matrix ferroelectric composites can be calculated by accurately controlling the volume of Ferrite particles. At the point of validation, the proposed approach makes visual and numeric comparisons between the morphology of the real microstructure and the model generated by the proposed technique. The simulation results by our method was essentially in agreement with experimental results in other literature. Simulation Experimental results also demonstrate that the dielectric constant of PZT matrix ferroelectric composites is significantly changed while the volume ratio of high dielectric phase particles was below 20%. PZT matrix ferroelectric composites Consequently, this method can be easily extended to composites preparation.

Inversion of Microwave Scattering Patterns

1971 ◽  
Vol 49 (24) ◽  
pp. 3082-3094 ◽  
Author(s):  
A. Fedotowsky ◽  
G. Boivin ◽  
R. Tremblay
Keyword(s):  
Dielectric Constant ◽  
Radial Variation ◽  
Inversion Method ◽  
Microwave Scattering ◽  
Scattering Pattern ◽  
Dielectric Target

An inversion method which reproduces the radial variation of dielectric constant in a dielectric target from its microwave scattering pattern is presented. Inversion criteria are developed showing what part of the target can be reconstructed. The technique is applied to experimentally measured scattering patterns.

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