نتایج جستجو برای: permittivity

تعداد نتایج: 5151  

2007
R. K. Challa D. Kajfez J. R. Gladden A. Z. Elsherbeni S. P. Ojha

Modifications in the measurement of the complex permittivity are described, based on the transmission and reflection coefficients of a dielectric slab. The measurement uses TRL twoport calibration to bring the reference planes accurately to the sample surface. The complex permittivity as a function of frequency is computed by minimizing the difference between the measured and the ideal scatteri...

Journal: :Nanoscale 2015
Richard Renou Anthony Szymczyk Aziz Ghoufi

The dielectric properties of sodium chloride solutions confined in a hydrophilic nanocavity were investigated by means of molecular dynamics simulations. Unlike what is observed in the bulk phase, three dielectric regimes were evidenced, namely an anomalous increase in the dielectric permittivity at low concentrations (with respect to confined pure water), a dielectric plateau at intermediate c...

2005
Constantine T. Dervos Christos D. Paraskevas Panayotis D. Skafidas Panayota Vassiliou

This work investigates the use of a specially designed cylindrical metal cell, in order to obtain complex permittivity and tanδ data of highly insulating High Voltage (HV) transformer oil samples. The data are obtained at a wide range of frequencies and operation temperatures to demonstrate the polarization phenomena and the thermally stimulated effects. Such complex permittivity measurements m...

2015
Jun Liu Yukun Yuan Zhong Ren Qiu-lin Tan Jijun Xiong

The accurate characterization of the temperature-dependent permittivity of aluminum nitride (AlN) ceramic is quite critical to the application of wireless passive sensors for harsh environments. Since the change of the temperature-dependent permittivity will vary the ceramic-based capacitance, which can be converted into the change of the resonant frequency, an LC resonator, based on AlN cerami...

2015
I. A. Tsekmes P. H. F. Morshuis J. J. Smit R. Kochetov

In this study, epoxy-cubic boron nitride composites are fabricated, and their dielectric response is investigated. They exhibit the same trend as epoxy composites reinforced with other filler types. Thus, at low filler concentrations, they exhibit a lower relative permittivity than neat epoxy. As the fill grade further increases, the relative permittivity of the composites increases as well. It...

2014
Michael D Janezic Jolene D Splett Kevin J Coakley

We investigate the feasibility of using dielectric spectra to classify hazardous and nonhazardous liquids. The dielectric spectra of several liquids was obtained with a shielded-open coaxial fixture, and we present a new full-wave model for calculating the complex permittivity of liquids using this fixture. Using the measured complex permittivity for each liquid, we examine several classificati...

Journal: :The Journal of microwave power and electromagnetic energy : a publication of the International Microwave Power Institute 2007
Boris Kapilevich Boris Litvak Vladimir Wainstein Danny Moshe

An improved measurement method of complex permittivity of low loss polymer powders is suggested. The measurements are done in the mm-wave range using a quasi optical resonator. The 2-D corrugated mode exciter is employed to improve suppression of undesirable higher modes. The model used for reconstructing complex permittivity takes into account ohm losses of metal mesh coupling that provide bet...

2008
A. Sharma G. Singh

In this paper, we have simulated a single-pin-shorted microstrip line fed three-dielectric-layer (with different permittivity and thickness) rectangular patch microstrip antenna for all those communication systems whose limited antenna size is premium. Low permittivity hard foam has been used as one substrate to achieve wide bandwidth. The simulation of this proposed antenna has been performed ...

Journal: :Physical review letters 2014
Jie Luo WeiXin Lu ZhiHong Hang HuanYang Chen Bo Hou Yun Lai C T Chan

We propose a method to control electromagnetic flux in an almost arbitrary way in wavelength and subwavelength scales. The capability of subwavelength flux control is enabled by the evanescent waves induced in a class of inhomogeneous anisotropic media with a near-zero permittivity component. By designing the spatial profile of the other permittivity component in such inhomogeneous media, the f...

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