scholarly journals Features of electromagnetic wave propagation in two- and three-layer cylindrical dielectric waveguides

2019 ◽  
Vol 30 ◽  
pp. 06006
Author(s):  
Alexander G. Shein ◽  
Tatiana S. Kharlanova
Keyword(s):  
Electromagnetic Waves ◽  
Dielectric Waveguide ◽  
Electromagnetic Wave Propagation ◽  
Azimuthal Angle ◽  
Transverse Magnetic ◽  
Cylindrical Shape ◽  
Dielectric Waveguides ◽  
Power Flux ◽  
Open Dielectric Waveguide ◽  
Layer Waveguide

Various characteristics of electromagnetic waves propagating in two- and three-layer open-dielectric waveguide structures of cylindrical shape are studied. Parameters of wave components in separate areas of the waveguide are considered. Electrodynamic characteristics and frequency dependencies for several values of layer dielectric permittivity obtained during the study are analyzed. The corresponding graphs of dependencies are presented. The dependencies of the power flux density of transverse magnetic (TM) waves in two- and three-layer waveguide structures in the absence of field dependence on azimuthal angle are considered.

Electromagnetic field generated by an off‐axis source in a cylindrically layered medium with an arbitrary number of horizontal discontinuities

Geophysics ◽  
1993 ◽  
Vol 58 (5) ◽  
pp. 616-625 ◽  
Author(s):  
Qing‐Huo Liu
Keyword(s):  
Arbitrary Number ◽  
Electromagnetic Waves ◽  
Layered Medium ◽  
Azimuthal Angle ◽  
Well Logging ◽  
Transverse Magnetic ◽  
Numerical Results ◽  
Optical Fiber Communications ◽  
Eccentricity Effect ◽  
Large Eccentricity

We investigate the propagation of electromagnetic waves in a cylindrically layered medium with an arbitrary number of horizontal discontinuities. The dielectric constant, conductivity, and magnetic permeability of the medium are functions of ρ and z only (i.e., independent of the azimuthal angle ϕ), but the field generated by an off‐axis source in this medium is in general a function of ρ, ϕ, and z. This two and a half‐dimensional (2.5-D) problem is often encountered in electromagnetic well logging, as well as in other areas such as optical fiber communications and integrated optics. We show that a coupling exists between the transverse electric (TE) and transverse magnetic (TM) components of the field even in the absence of the horizontal discontinuities, which makes it difficult to solve for the field. We apply an efficient numerical mode‐matching (NMM) algorithm to tackle this 2.5-D problem. This algorithm uses the local reflection and transmission operators developed in the recent work on the diffraction of nonaxisymmetric waves in a cylindrically layered medium with a single horizontal discontinuity. For several special geometries, we compare the numerical results from this NMM algorithm with analytical solutions as well as the earlier numerical results for axisymmetric cases, and found excellent agreement between them. As an application to the geophysical subsurface sensing, we solve several practical problems, and find that a large eccentricity effect can occur in realistic electromagnetic well logging. Moreover, this large eccentricity effect is strongly coupled with thin‐bed effect. Conventional log interpretation methods cannot adequately account for these effects. With the NMM algorithm developed here, all these different effects can be accounted for simultaneously and accurately.

scholarly journals Numerical Method for Electromagnetic Wave Propagation Problem in a Cylindrical Anisotropic Waveguide with Longitudinal Magnetization

2019 ◽  
Vol 8 (4) ◽  
pp. 130-135
Author(s):  
E. Smolkin ◽  
M. Snegur
Keyword(s):  
Electromagnetic Waves ◽  
Dielectric Waveguide ◽  
Electromagnetic Wave Propagation ◽  
Physical Problem ◽  
Longitudinal Magnetization ◽  
Spectral Parameters ◽  
Transmission Eigenvalue ◽  
Wave Propagation Problem ◽  
Transmission Eigenvalue Problem ◽  
Anisotropic Waveguide

The propagation of monochromatic electromagnetic waves in metal circular cylindrical dielectric waveguide with longitudinal magnetization filled with anisotropic inhomogeneous waveguide is considered. The physical problem is reduced to solving a transmission eigenvalue problem for a system of ordinary differential equations. Spectral parameters of the problem are propagation constants of the waveguide. Numerical results are obtained using a modification of the projecting methods. The comparison with known exact solutions (for particular values of parameters) are made.

scholarly journals NUMERICAL METHOD FOR ELECTROMAGNETIC WAVE PROPAGATION PROBLEM IN A CYLINDRICAL INHOMOGENEOUS METAL DIELECTRIC WAVEGUIDING STRUCTURES

2017 ◽  
Vol 22 (3) ◽  
pp. 271-282 ◽  
Author(s):  
Eugene Smolkin
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Physical Problem ◽  
Dielectric Waveguides ◽  
Spectral Parameters ◽  
Transmission Eigenvalue ◽  
Wave Propagation Problem ◽  
Transmission Eigenvalue Problem

The propagation of monochromatic electromagnetic waves in metal circular cylindrical dielectric waveguides filled with inhomogeneous medium is considered. The physical problem is reduced to solving a transmission eigenvalue problem for a system of ordinary differential equations. Spectral parameters of the problem are propagation constants of the waveguide. Numerical results are found with a projection method. The comparison with known exact solutions (for particular values of parameters) is made.

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

Electromagnetic wave propagation in a chiroplasma-filled waveguide

1999 ◽  
Vol 62 (1) ◽  
pp. 87-94 ◽  
Author(s):  
J. GONG
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Cross Section ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Propagation Constant ◽  
Circular Cross Section ◽  
Propagation Characteristics ◽  
Waveguide Modes ◽  
The Family

A dispersion equation is derived for a cylindrical waveguide of circular cross-section partially filled with chiroplasma. The propagation characteristics of electromagnetic waves in the family of waveguide modes are studied. The dispersion curves are given. It is found that the propagation constant changes almost linearly with the chirality admittance for the parameters that we choose, and increases with increasing filled area.

scholarly journals An Insight into Creeping Electromagnetic Waves around the Human Body

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Branimir Ivsic ◽  
Davor Bonefacic ◽  
Zvonimir Sipus ◽  
Juraj Bartolic
Keyword(s):  
Wave Propagation ◽  
Human Body ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Axial Magnetic Field ◽  
Magnetic Dipoles ◽  
Wearable Antennas ◽  
Field Decay ◽  
Theoretical Considerations ◽  
Insight Into

The electromagnetic wave propagation around human body torso is modelled by considering elementary electric and magnetic dipoles over an infinite muscle-equivalent cylinder. The poles in the spectral domain Green’s function with smallest imaginary part are found to correspond to creeping wave propagation coefficients which predict the general trend in propagation around human body. In addition, it was found that axial magnetic field component is crucial for communication via creeping waves since it generates modes with smaller field decay compared to axial electric field. The developed model may thus serve as a practical guideline in design of on-body wearable antennas. The theoretical considerations are verified with simulations and measurements on the prototype of PIFA antenna placed on the human body.

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