Properties of electromagnetic waves in ferrites

In this paper we present a derivation of the general wave equation governing the propagation of electromagnetic waves in ferrites. This is shown to be equivalent to the usual Helmholtz form obtained by introducing a permeability tensor. Its real underlying structure is somewhat obscured by the Helmholtz form because in this form the time dependence is submerged in the frequency-dependent elements of the permeability tensor. However, the main purpose of the paper is to provide a systematic account of the properties of electromagnetic waves in ferrites and this is done by making use of the close analogy that exists between wave propagation in ferrites and that in cold magnetized plasmas. This facilitates the construction of a so-called ‘C. M. A. diagram’ for a ferrite, which classifies the waves according to the various topologies of the refractive index and ray surfaces (along with the associated wave polarizations) in a two-dimensional parameter space that relates the wave frequency to the precessional frequencies intrinsic to the magnetization of the ferrite. The insight into the behaviour of waves in ferrites that this approach provides is illustrated in connection with the phenomena of cut-offs, resonances and wave-focusing, which give rise to caustics.

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Numerical study of Love wave propagation

Geophysics ◽

10.1190/1.1441515 ◽

1983 ◽

Vol 48 (7) ◽

pp. 833-853 ◽

Cited By ~ 14

Author(s):

K. R. Kelly

Keyword(s):

Numerical Modeling ◽

Wave Propagation ◽

Love Wave ◽

Fourier Transforms ◽

Narrow Band ◽

Numerical Study ◽

Two Dimensional ◽

Band Pass ◽

The Waves ◽

Insight Into

Love wave propagation is studied by investigating numerical modeling results for several examples of geologic interest. The modal characteristics of the results are clarified by the use of narrow band‐pass filters and two‐dimensional Fourier transforms in range and time. Such processing makes it possible to study changes in phase and group velocity for the various modes and to locate points of reflection. This permits one to gain insight into changes in the physical properties of the surface channel supporting the waves.

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Anomalous Anderson localization behavior in gain-loss balanced non-Hermitian systems

Nanophotonics ◽

10.1515/nanoph-2020-0306 ◽

2020 ◽

Vol 10 (1) ◽

pp. 443-452

Author(s):

Tianshu Jiang ◽

Anan Fang ◽

Zhao-Qing Zhang ◽

Che Ting Chan

Keyword(s):

Wave Propagation ◽

Electromagnetic Waves ◽

Anderson Localization ◽

Random Media ◽

Normal Incidence ◽

Disordered Media ◽

One Dimensional ◽

Gain Loss ◽

The Waves ◽

Localization Behavior

AbstractIt has been shown recently that the backscattering of wave propagation in one-dimensional disordered media can be entirely suppressed for normal incidence by adding sample-specific gain and loss components to the medium. Here, we study the Anderson localization behaviors of electromagnetic waves in such gain-loss balanced random non-Hermitian systems when the waves are obliquely incident on the random media. We also study the case of normal incidence when the sample-specific gain-loss profile is slightly altered so that the Anderson localization occurs. Our results show that the Anderson localization in the non-Hermitian system behaves differently from random Hermitian systems in which the backscattering is suppressed.

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Design of a Novel Miniaturized Frequency Selective Surface Based on 2.5-Dimensional Jerusalem Cross for 5G Applications

Wireless Communications and Mobile Computing ◽

10.1155/2018/3485208 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Peng Zhao ◽

Yihang Zhang ◽

Rongrong Sun ◽

Wen-Sheng Zhao ◽

Yue Hu ◽

...

Keyword(s):

Resonant Frequency ◽

Equivalent Circuit ◽

Equivalent Circuit Model ◽

Frequency Selective Surface ◽

Size Reduction ◽

Two Dimensional ◽

Physical Insight ◽

Frequency Selective ◽

Significant Size ◽

Insight Into

A compact frequency selective surface (FSS) for 5G applications has been designed based on 2.5-dimensional Jerusalem cross. The proposed element consists of two main parts: the successive segments of the metal traces placed alternately on the two surfaces of the substrate and the vertical vias connecting traces. Compared with previous published two-dimensional miniaturized elements, the transmission curves indicate a significant size reduction (1/26 wavelengths at the resonant frequency) and exhibit good angular and polarization stabilities. Furthermore, a general equivalent circuit model is established to provide direct physical insight into the operating principle of this FSS. A prototype of the proposed FSS has been fabricated and measured, and the results validate this design.

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Multiple phases in a generalized Gross-Witten-Wadia matrix model

Journal of High Energy Physics ◽

10.1007/jhep09(2020)081 ◽

2020 ◽

Vol 2020 (9) ◽

Cited By ~ 2

Author(s):

Jorge G. Russo ◽

Miguel Tierz

Keyword(s):

Partition Function ◽

Matrix Models ◽

Characteristic Polynomial ◽

Matrix Model ◽

Phase Structure ◽

Unitary Matrix ◽

Two Dimensional ◽

Toeplitz Determinants ◽

Dimensional Parameter ◽

Planar Limit

Abstract We study a unitary matrix model of the Gross-Witten-Wadia type, extended with the addition of characteristic polynomial insertions. The model interpolates between solvable unitary matrix models and is the unitary counterpart of a deformed Cauchy ensemble. Exact formulas for the partition function and Wilson loops are given in terms of Toeplitz determinants and minors and large N results are obtained by using Szegö theorem with a Fisher-Hartwig singularity. In the large N (planar) limit with two scaled couplings, the theory exhibits a surprisingly intricate phase structure in the two-dimensional parameter space.

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Forest Height Estimation Based on P-Band Pol-InSAR Modeling and Multi-Baseline Inversion

Remote Sensing ◽

10.3390/rs12081319 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1319

Author(s):

Xiaofan Sun ◽

Bingnan Wang ◽

Maosheng Xiang ◽

Liangjiang Zhou ◽

Shuai Jiang

Keyword(s):

Standard Deviation ◽

Vertical Structure ◽

Incidence Angle ◽

Three Dimensional ◽

Solution Space ◽

Model Complexity ◽

Two Dimensional ◽

Dimensional Parameter ◽

Model Inversion ◽

Forest Height

The Gaussian vertical backscatter (GVB) model has a pivotal role in describing the forest vertical structure more accurately, which is reflected by P-band polarimetric interferometric synthetic aperture radar (Pol-InSAR) with strong penetrability. The model uses a three-dimensional parameter space (forest height, Gaussian mean representing the strongest backscattered power elevation, and the corresponding standard deviation) to interpret the forest vertical structure. This paper establishes a two-dimensional GVB model by simplifying the three-dimensional one. Specifically, the two-dimensional GVB model includes the following three cases: the Gaussian mean is located at the bottom of the canopy, the Gaussian mean is located at the top of the canopy, as well as a constant volume profile. In the first two cases, only the forest height and the Gaussian standard deviation are variable. The above approximation operation generates a two-dimensional volume only coherence solution space on the complex plane. Based on the established two-dimensional GVB model, the three-baseline inversion is achieved without the null ground-to-volume ratio assumption. The proposed method improves the performance by 18.62% compared to the three-baseline Random Volume over Ground (RVoG) model inversion. In particular, in the area where the radar incidence angle is less than 0.6 rad, the proposed method improves the inversion accuracy by 34.71%. It suggests that the two-dimensional GVB model reduces the GVB model complexity while maintaining a strong description ability.

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Exact Solutions and Conserved Vectors of the Two-Dimensional Generalized Shallow Water Wave Equation

Mathematics ◽

10.3390/math9121439 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1439

Author(s):

Chaudry Masood Khalique ◽

Karabo Plaatjie

Keyword(s):

Differential Equation ◽

Wave Equation ◽

Shallow Water ◽

Water Wave ◽

Elliptic Integral ◽

Momentum Conservation ◽

Two Dimensional ◽

Order Ordinary Differential Equation ◽

Closed Form Solutions ◽

Shallow Water Wave

In this article, we investigate a two-dimensional generalized shallow water wave equation. Lie symmetries of the equation are computed first and then used to perform symmetry reductions. By utilizing the three translation symmetries of the equation, a fourth-order ordinary differential equation is obtained and solved in terms of an incomplete elliptic integral. Moreover, with the aid of Kudryashov’s approach, more closed-form solutions are constructed. In addition, energy and linear momentum conservation laws for the underlying equation are computed by engaging the multiplier approach as well as Noether’s theorem.

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A new look at the simple epidemic process

Journal of Applied Probability ◽

10.1017/s0021900200046325 ◽

1979 ◽

Vol 16 (01) ◽

pp. 198-202 ◽

Cited By ~ 5

Author(s):

L. Billard ◽

H. Lacayo ◽

N. A. Langberg

Keyword(s):

Waiting Times ◽

Classical Model ◽

Epidemic Models ◽

Underlying Structure ◽

Epidemic Process ◽

Insight Into ◽

New Look

Classical epidemic models have invariably proved to be mathematically intractable. By considering the distribution of the number of infectives in a simple epidemic process as a convolution of exponential waiting times, the solution to the classical model is obtained easily giving more insight into the underlying structure. The idea can be extended to other simple epidemic models.

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Dynamics with Cattaneo–Christov heat and mass flux theory of bioconvection Oldroyd-B nanofluid

Advances in Mechanical Engineering ◽

10.1177/1687814020930464 ◽

2020 ◽

Vol 12 (8) ◽

pp. 168781402093046 ◽

Cited By ~ 2

Author(s):

Noor Saeed Khan ◽

Qayyum Shah ◽

Arif Sohail

Keyword(s):

Mass Transfer ◽

Porous Media ◽

Differential Equations ◽

Mass Flux ◽

Homotopy Analysis Method ◽

Two Dimensional ◽

Analysis Method ◽

Homotopy Analysis ◽

Transfer Flow ◽

Insight Into

Entropy generation in bioconvection two-dimensional steady incompressible non-Newtonian Oldroyd-B nanofluid with Cattaneo–Christov heat and mass flux theory is investigated. The Darcy–Forchheimer law is used to study heat and mass transfer flow and microorganisms motion in porous media. Using appropriate similarity variables, the partial differential equations are transformed into ordinary differential equations which are then solved by homotopy analysis method. For an insight into the problem, the effects of various parameters on different profiles are shown in different graphs.

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