نتایج جستجو برای: permittivity

تعداد نتایج: 5151  

2004
Jonathan H. Jiang Dong L. Wu

Recent advances in satellite remote sensing at near-millimeter and sub-millimeter wavelengths (~100-3000 GHz) require accurate complex permittivity for ice and liquid water at these frequencies for different temperatures, especially for cold atmospheric conditions. This paper summarizes the existing experimental permittivity data in the literature, and provides an updated empirical ice permitti...

2014
Chanchal Yadav

In transmission-reflection method, the microstrip transmission line coated with an organic polymer as an overlay is used to estimate the permittivity of the polymer film. Scattering parameter response of the microstrip line varies as the permittivity of the overlay or its thickness changes. The permittivity is estimated by minimizing the difference between the theoretical (computed from the ana...

Photonic band-gap (PBG) crystals offer new dimensions of freedom in controlling propagation of electromagnetic waves. The existence of stop-bands in the transmission characteristic of these crystals makes them a suitable element for the realization of many useful microwave and optical subsystems. In this paper, we calculate the propagation constant of a one-dimensional (1-D) photonic crystal by...

2015
T. P. Leão J. S. Tyner

Mixing models help describe the contribution of liquid, gas, and solid phases to the bulk dielectric permittivity of porous materials. They are particularly useful when studying the electromagnetic properties of the vadose zone using TDR or GPR techniques. The objective of this research was to evaluate the Lichtenecker Mixing Model applied to undisturbed and repacked soil data collected with a ...

Journal: :رادار 0
کمال جانقربان رحیم اقرء حبیب دانش منش حبیب اله عبیری

in this research, electromagnetic properties of graphene-epoxy nanocomposite up to 3wt% graphene, were investigated in x band. results showed that these nanocomposites do not have significant permeability so that it can be considered equal to 1. however they exhibit high permittivity such that real part of permittivity of 3wt% graphene sample is 8.4 in 8ghz and 6.8 in 12ghz frequencies, which a...

Journal: :Applied optics 2001
P Gay-Balmaz O J Martin

We contribute to the study of the optical properties of high-permittivity nanostructures deposited on surfaces. We present what we believe is a new computational technique derived from the coupled-dipole approximation (CDA), which can accommodate high-permittivity scatterers. The discretized CDA equations are reformulated by use of the sampling theory to overcome different sources of inaccuracy...

2012
Arti Vaish Harish Parthasarathy

In this paper, a novel wave equation for electromagnetic waves in a medium having anisotropic permittivity has been derived with the help of Maxwell’s curl equations. The x and y components of the Maxwell’s equations are written with the permittivity ( ) being a 3× 3 symmetric matrix. These equations are solved for Ex , Ey, Hx, Hy in terms of Ez , Hz, and the partial derivatives. The Z componen...

2010
Mingda Huang M. Imran Kazim Matti H. A. J. Herben

The relative permittivity of LCP material has been characterized within the whole 60 GHz frequency band using the microstrip ring resonator (MRR) method. Using a circuit model, the gap capacitance of the MRR has been taken into account in order to improve the accuracy of the determined relative permittivity. The results show that the relative permittivity of LCP is almost constant (εr ≈ 3.1) wi...

Journal: :international journal of civil engineering 0
ali pak azadi ave., tehran zahra zahmatkesh azadi ave., tehran

geotextiles are one of the most widely used synthetic materials in filtration and drainage applications. since in real applications, geotextiles are subjected to various hydraulic gradients and confining stresses, hydraulic behavior of geotextiles under different circumstances is of great practical importance. in this study filtration and drainage properties of several nonwoven needle-punched g...

2006
N. Shi R. Ramprasad

A recently developed theory of atomic-scale local dielectric permittivity has been used to determine the position dependent permittivity profiles of a few nanoscale insulator surfaces and multilayers. Specifically, slabs containing single-component Si, polymer, and SiO2 and two-component Si-SiO2 and polymer-SiO2 systems of technological importance have been studied. The present approach indicat...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید