Resonant cavity for the measurement of microwave magnetic permeability using the small perturbation theory

2008 ◽  
Vol 50 (2) ◽  
pp. 399-402 ◽  
Author(s):  
D. X. Gouveia ◽  
L. C. Costa ◽  
M. A. Valente
Keyword(s):  
Perturbation Theory ◽  
Small Perturbation ◽  
Magnetic Permeability ◽  
Resonant Cavity ◽  
Microwave Magnetic Permeability

A 5 GHz Resonant Cavity for Complex Permittivity Measurements: Design, Test Performances and Application

2006 ◽  
Vol 514-516 ◽  
pp. 1561-1565 ◽  
Author(s):  
Luís Cadillon Costa ◽  
Susana Devesa ◽  
François Henry
Keyword(s):  
Perturbation Theory ◽  
Quality Factor ◽  
Small Perturbation ◽  
Complex Permittivity ◽  
Resonant Cavity ◽  
Cavity Resonator ◽  
Finite Conductivity ◽  
Theoretical Treatment ◽  
Resonance Frequencies ◽  
5 Ghz

The theoretical treatment of a cavity resonator consists of solving the Maxwell equations in that cavity, respecting the boundary conditions. The resonance frequencies appear as conditions in the solutions of the differential equation involved and are not significantly affected by the fact that the cavity walls have a finite conductivity. Solutions for rectangular cavities and for the lowest resonant mode, where the probability of mistaking one mode from another is slight, are readily obtained. The measurement of the complex permittivity, ε* = ε´-iε´´, can be made using the small perturbation theory. In this method, the resonance peak frequency and the quality factor of the cavity, with and without a sample, can be used to obtain the complex dielectric permittivity of the material. We measure the shift in the resonant frequency of the cavity, f, caused by the insertion of the sample, which can be related to the real part of the complex permitivitty, ε´, while the change in the inverse of the quality factor of the cavity, (1/Q), gives the imaginary part, ε´´. In this work we report the construction details, the performance tests of the cavity to confirm the possibility of the use of the small perturbation theory, and the application of the technique to measure the complex permittivity of a reinforced plastic.

Low-field microwave magnetic permeability on FeSiBNbCu thin films

2006 ◽  
Vol 384 (1-2) ◽  
pp. 271-273 ◽  
Author(s):  
A.D.C. Viegas ◽  
L. Santi ◽  
M.A. Correa ◽  
R.B. da Silva ◽  
A.M.H. de Andrade ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Permeability ◽  
Low Field ◽  
Microwave Magnetic Permeability

Nonlinear Sloshing in Fixed and Vertically Excited Containers

2002 ◽  
Author(s):  
Jannette B. Frandsen ◽  
Alistair G. L. Borthwick
Keyword(s):  
Perturbation Theory ◽  
Free Surface ◽  
Small Perturbation ◽  
Numerical Solutions ◽  
Vertical Direction ◽  
Nonlinear Effects ◽  
Breaking Waves ◽  
Surface Flow ◽  
Nonlinear Behaviour ◽  
Computational Domain

Nonlinear effects of standing wave motions in fixed and vertically excited tanks are numerically investigated. The present fully nonlinear model analyses two-dimensional waves in stable and unstable regions of the free-surface flow. Numerical solutions of the governing nonlinear potential flow equations are obtained using a finite-difference time-stepping scheme on adaptively mapped grids. A σ-transformation in the vertical direction that stretches directly between the free-surface and bed boundary is applied to map the moving free surface physical domain onto a fixed computational domain. A horizontal linear mapping is also applied, so that the resulting computational domain is rectangular, and consists of unit square cells. The small-amplitude free-surface predictions in the fixed and vertically excited tanks compare well with 2nd order small perturbation theory. For stable steep waves in the vertically excited tank, the free-surface exhibits nonlinear behaviour. Parametric resonance is evident in the instability zones, as the amplitudes grow exponentially, even for small forcing amplitudes. For steep initial amplitudes the predictions differ considerably from the small perturbation theory solution, demonstrating the importance of nonlinear effects. The present numerical model provides a simple way of simulating steep non-breaking waves. It is computationally quick and accurate, and there is no need for free surface smoothing because of the σ-transformation.

scholarly journals High Microwave Magnetic Permeability of Composites with Submicron Iron Flakes

2011 ◽  
Vol 266 ◽  
pp. 012025 ◽  
Author(s):  
M A Abshinova ◽  
S M Matitsine ◽  
L Liu ◽  
C R Deng ◽  
L B Kong
Keyword(s):  
Magnetic Permeability ◽  
Microwave Magnetic Permeability

FIELD MEASUREMENTS WITHIN A LARGE RESONANT CAVITY BASED ON THE PERTURBATION THEORY

2014 ◽  
Vol 57 ◽  
pp. 1-20
Author(s):  
Mohamed Nasserdine ◽  
Stephanie Mengue ◽  
Christophe Bourcier ◽  
Elodie Richalot
Keyword(s):  
Perturbation Theory ◽  
Resonant Cavity ◽  
Field Measurements

Composite of Flake-Shape Sendust Particles and its Application on Patch Antenna

2013 ◽  
Vol 765-767 ◽  
pp. 3086-3089
Author(s):  
Meng Ran Guan ◽  
Xin Wang ◽  
Hui Bin Zhang ◽  
Long Jiang Deng ◽  
Jian Liang Xie
Keyword(s):  
Ball Milling ◽  
Magnetic Permeability ◽  
Patch Antenna ◽  
Shape Factor ◽  
Effective Magnetic Permeability ◽  
Simulation Results ◽  
Microwave Magnetic Permeability ◽  
Very High ◽  
Type Composite

Flake-shape Sendust particles with high microwave magnetic permeability and permittivity were prepared with the method of wet ball milling, and then mixed with the polymer to get a sheet-type composite as an effective EMW absorber. It was found that the composite has a very high shape factor owing to the flaky Sendust particles, which can break through the traditional Snoeks limit, and achieve a high effective magnetic permeability. HFSS simulation results show the sheet-type composite can be used on the patch antenna for improving the front-to-back ratio of the hand-held patch antenna and reducing the EMW pollution around antenna operators.

scholarly journals On Perturbations of Continuous Maps

2013 ◽  
Vol 56 (1) ◽  
pp. 92-101
Author(s):  
Benoît Jacob
Keyword(s):  
Perturbation Theory ◽  
Topological Space ◽  
Small Perturbation ◽  
Sufficient Conditions ◽  
Matrix Perturbation ◽  
Continuous Map ◽  
Matrix Perturbation Theory ◽  
Continuous Maps

AbstractWe give sufficient conditions for the following problem: given a topological space X, ametric space Y, a subspace Z of Y, and a continuous map f from X to Y, is it possible, by applying to f an arbitrarily small perturbation, to ensure that f(X) does not meet Z? We also give a relative variant: if f(X') does not meet Z for a certain subset X'⊂ X, then we may keep f unchanged on X'. We also develop a variant for continuous sections of fibrations and discuss some applications to matrix perturbation theory.

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