scholarly journals To the Question of the Independence of the Surface Electromagnetic Wave Frequency

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
V. K. Balkhanov ◽  
Yu B. Bashkuev
Keyword(s):  
Electromagnetic Wave ◽  
Layer Thickness ◽  
Dielectric Layer ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Wave Frequency ◽  
Waveguide Channel ◽  
Surface Electromagnetic Wave ◽  
Minimum Frequency ◽  
Waveguide Theory

Earth's the surface is often strongly inductive, consisting of a dielectric layer thickness endpoint, lying on an unlimited conductor basis. Electromagnetic wave, spreading along the surface, it appears captured dielectric layer, spreading it as in the waveguide channel. Waveguide theory it is known that the spread in the waveguide can only electromagnetic waves with a discrete set of frequencies. And experience shows that the captured waveguide channel electromagnetic waves can be any frequency. The article found that this behavior is due to the fact that electromagnetic waves in free space border - dielectric layer damped height in several wavelengths. Thus the thickness of the dielectric layer becomes more effectively, and this leads to a reduction of the minimum frequency of the waveguide. A discrete set of frequencies is blurred so that cover each other. Thus, a discrete set of frequencies becomes solid, and captured waveguide channel electromagnetic waves are independent of frequency.

Determination of the velocity of short electromagnetic waves by interferometry

1952 ◽  
Vol 213 (1112) ◽  
pp. 123-141 ◽  
Keyword(s):  
Phase Velocity ◽  
Electromagnetic Radiation ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Wave Beam ◽  
Wave Length ◽  
Wave Frequency ◽  
Space Wave

A new measurement of the velocity of electromagnetic radiation is described. The result has been obtained, using micro-waves at a frequency of 24005 Mc/s ( λ = 1∙25 cm), with a form of interferometer which enables the free-space wave-length to be evaluated. Since the micro-wave frequency can also be ascertained, phase velocity is calculated from the product of frequency and wave-length. The most important aspect of the experiment is the application to the measured wave-length of a correction which arises from diffraction of the micro-wave beam. This correction is new to interferometry and is discussed in detail. The result obtained for the velocity, reduced to vacuum conditions, is c 0 = 299792∙6 ± 0∙7 km/s.

scholarly journals Векторный потенциал электромагнитной волны над сильноиндуктивной двуслойной земной поверхностью

2019 ◽  
Vol 89 (9) ◽  
pp. 1439
Author(s):  
В.К. Балханов ◽  
Ю.Б. Башкуев ◽  
Л.Х. Ангархаева
Keyword(s):  
Electromagnetic Wave ◽  
Vector Potential ◽  
Electromagnetic Waves ◽  
Phase Speed ◽  
Singular Points ◽  
Effective Parameters ◽  
Surface Electromagnetic Wave ◽  
Light Speed ◽  
Sommerfeld Integral ◽  
Surface Electromagnetic Waves

The vertical components of the vector potential of an electromagnetic wave for a two-layer strongly inductive impedance medium are determined. The solution is presented as the Sommerfeld integral. The singular points of this integral were determined using the effective parameters. The question of the phase speed of a surface electromagnetic wave is considered. It is shown that it is always less than the light speed in a vacuum. This means that surface electromagnetic waves are not Zenneck waves, whose phase speed is greater than the light speed, like electromagnetic waves in waveguides.

NONLINEAR DEMODULATION OF AN AMPLITUDE-MODULATED ELECTROMAGNETIC WAVE PROPAGATING IN A MAGNETOPLASMA

1967 ◽  
Vol 45 (12) ◽  
pp. 3991-4010 ◽  
Author(s):  
Sant Ram ◽  
P. K. Kaw
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Applied Magnetic Field ◽  
Free Space ◽  
Numerical Results ◽  
Electric Vector ◽  
Wave Frequency ◽  
Plasma Parameters ◽  
Explicit Expressions

Explicit expressions for the electric vector of an amplitude-modulated electromagnetic wave propagating along the direction of an applied magnetic field in a nonlinear ionized medium have been obtained, when the wave frequency is equal to the gyrofrequency of the electrons. It is seen that the wave gets strongly demodulated after propagation through the magnetoplasma as well as after reflection from a magnetoplasma-free space interface. Some numerical results, illustrating the variation of the demodulation with various plasma parameters have been presented in the discussion.

Control of defects in the multilayer dielectric materials and coatings in the microwave range

2020 ◽  
Vol 86 (2) ◽  
pp. 37-43
Author(s):  
A. I. Kaz’min ◽  
P. A. Fedyunin
Keyword(s):  
Electromagnetic Wave ◽  
Frequency Dependence ◽  
Attenuation Coefficient ◽  
Electromagnetic Waves ◽  
Dielectric Materials ◽  
Geometric Parameters ◽  
Microwave Range ◽  
Surface Electromagnetic Wave ◽  
Phase Measurements ◽  
Multilayer Dielectric

The development of modern engineering is inextricably linked with the development of the new types of multilayer dielectric materials. Existing radio wave methods for monitoring interlayer defects in such materials exhibit low accuracy in reconstructing the geometric parameters of defects. The results of studying extended interlayer defects in the three-layer coating consisting of polymethyl methacrylate, F-4D PTFE, and semi-hard rubber by the method of surface electromagnetic waves are presented. The method is based on the solution of inverse problems in the reconstruction of the geometric parameters of extended interlayer defects of special multilayer materials and coatings from the frequency dependence of the attenuation coefficient of the field of a slow surface electromagnetic wave. Unlike the methods that make use from the complex reflection coefficient we proposed to increase the accuracy of the reconstruction of the geometric parameters of extended interlayer defects taking into account the linear frequency dependence of the attenuation coefficient as well as reducing the number of fixed measurement frequencies. Moreover, the determination procedure is rather simple, since only the field strength of the surface electromagnetic wave is measured, and there is no need for phase measurements. Experimental data obtained on a multifrequency measuring complex in the range of 10 – 11 GHz were used for reconstruction of the interlayer defects in the coating under study. The developed method provided a relative error of thickness estimation below 10%. The proposed method approach can be used in studying multilayer dielectric coatings on the metal for detection of delamination in the lack of glue or poor adhesion between the layers. The developed method is also suitable for control of the defects in semiconductors, ferrite and composite materials.

scholarly journals Interaction of electromagnetic waves in an ice layer

2019 ◽  
Vol 127 ◽  
pp. 02011
Author(s):  
Vladimir Korochentsev ◽  
Wei Xue ◽  
Gennadiy Shabanov ◽  
Artem Em ◽  
Yuliya Shpak
Keyword(s):  
Mathematical Model ◽  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Wave Amplitude ◽  
Spherical Wave ◽  
Ice Thickness ◽  
Suggested Model ◽  
Ice Surface

A mathematical model for spherical wave propagation near an ice layer has been developed. The proposed mathematical model is based on the directed Green’s functions with boundary conditions with irregular angles. Based on the suggested model, we analyzed a field of a point directed source radiating electromagnetic waves in two cases: the source is in the air and is radiating waves along the marine ice surface; the source is in the ice layer and radiating waves. Results of the modeling for different frequencies and different ice thickness are described. It was shown that wave amplitude increases by about two times inside the ice if compared to free space. Electromagnetic wave propagating along marine ice surface increases by 50% compared to the wave propagating in free space.

MODULATION OF ELECTROMAGNETIC WAVES BY ACOUSTIC WAVES IN A PLASMA

1964 ◽  
Vol 42 (8) ◽  
pp. 1635-1642 ◽  
Author(s):  
Mahendra Singh Sodha ◽  
Carl James Palumbo
Keyword(s):  
Electromagnetic Wave ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Reflected Waves

This communication presents an analysis of the modulation of an electromagnetic wave, propagating in a plasma, in which an acoustic wave is present. The modulation of the transmitted and reflected waves from a plasma-free space interface has also been analyzed. A discussion of the results obtained has also been given.

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.

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