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Comparison of Excitation of Acoustic-Electromagnetic Wave in Piezoelecric Crystal and Crystal with Potential of Deformation

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Journal of Electromagnetic Analysis and Applications 2015年第10期7卷 259-264页

作者： S. Koshevaya v. grimalsky Y. Kotsarenko J. Escobedo-Alatorre Autonomous University of Morelos State CIICAp Cuernavaca Mexico

In this article, the comparison of excitation in high frequencies of acoustic-electromagnetic wave in piezoelecric crystal and crystal with potential of deformation GaAs is investigating. Possible mechanisms of coupling different hybrid waves are the piezoeffect and the deformation potential. As a model it is analyzing a film of crystal places between two symmetrical substrates with the other materials without an acoustic contact. This film includes 2D electron gas with a high negative differential conductivity and uniform initial distribution of electrons. The hybrid acoustic-electromagnetic wave and hybrid space charge wave interact. Amplification of space charge wave takes place due to negative differential conductivity in GaAs. This amplification of space charge waves is causing the amplification of acoustic-electromagnetic wave. It is to show that the symmetric modes, emerging as transverse ones, interact more effectively with the space charge waves. Another important result is the following: at the frequencies f ≈ 10 GHz, the excitation efficiency of acoustic-electromagnetic wave with transverse displacement due to piezoeffect is more effective, but at higher frequencies, the deformation potential is dominating.

关键词： Piezoelectric Crystal Deformation Potential Acoustic-Electromagnetic and Space Charge Waves

Explosions and seismic phenomena based on exciting of acoustic-electromagnetic waves

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Natural Science 2012年第8期4卷 652-658页

作者： S. Koshevaya v. grimalsky G. Urquiza M. Tecpoyotl A. Kotsarenko v. Yutsis N. Makarets Center of Geosciences National Autonomous University of Mexico (UNAM) Juriquilla ZP 76230 Qro. Mexico CIICAp Autonomous University of State Morelos (UAEM) Cuernavaca ZP 62209 Mor. Mexico Faculty of Earth Sciences Autonomous University of Nuevo Leon (UANL) Linares ZP 67700 NL Mexico Physical Faculty T. Shevchenko National University Kyiv ZP 01033 Ukraine

During earthquakes and strong underground explosions it is possible to observe two different effects. The first one is connected with the destruction of media, and this causes acoustic and later hybrid acoustic-electromagnetic waves in an epicenter in the atmosphere and in the ionosphere. Another one is connected with cracks in crystals of rocks, which seems more interesting, because it is possible to recognize the natural earthquakes and industrial explosions. In the first effects due to nonlinear elastic modules the acoustic waves move through the lithosphere and transform their spectra from vLF (very low frequencies ~ 1 - 10 kHz) at the depth of about 30 km into the lower part of ELF (extremely low frequencies, ~ 3 Hz - 1 kHz) on the Earth’s surface, then they pass the atmosphere and penetrate into the ionosphere. During the nonlinear acoustic passage through the atmosphere and the ionosphere, the spectrum transforms from ELF into ULF (ultra low frequencies, view article the classification of spectrum and analysis of two cases of the destruction of rocks in the lithosphere is presented. The rocks possess piezoelectric and piezomagnetic properties. In this case the electromagnetic emission is excited by the fracturing in plates of crystals. The difference of emission from piezoelectric and magnetic plates in cases of industrial explosions and natural seismic events including volcanic phenomena gives a possibility to analyze the method of its identification. The consideration is based on the model of the plate of a finite size with an uniformly moving crack.

关键词： Underground Explosion Nonlinear Passing of Acoustic Waves Piezoelectric and Magnetic Plates Difference Between Natural Seismic volcanic and Industrial Events

Simulation, Fabrication and Tests of a GPS Antenna on the Roof-Top of an Automobile

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Journal of Electromagnetic Analysis and Applications 2012年第12期4卷 504-512页

作者： Margarita Tecpoyotl-Torres Jose G. vera-Dimas Gustavo Urquiza Beltrán L. Cisneros-villalobos vladymyr grimalsky Svetlana v. Koshevaya Centro de Investigación en Ingeniería y Ciencias Aplicadas Universidad Autónoma del Estado de Morelos Cuernavaca Mexico.

It is very important for the car users to have several communication systems and many antennas, which respond to the demands of aesthetics and efficiency. In this case, it is necessary to consider different types of materials and geometries. Among the automobile systems, the navigation systems are found, which are formed by a Global Position System (GPS), with a pre-charged base of maps and highways in order to locate the vehicle. For the reception of the GPS signals, circularly polarized patch antennas are used, which must be designed to operate at 1.57 GHz. This work is focused on the analysis of a circular antenna performance, designed for GPS, by means of the simulation of the following cases: antenna without radome, antenna with acrylic radome, and, finally, antenna on the roof of an automobile, considering the effect of the complete chassis. A Basic, a Simplified and a More Simplified Advanced Car Models (BCM, SACM, and MSACM) were used in order to analyze the chassis shape. The simulations were carried out with the software FEKO. The fabrication and experimental and practical tests are also presented.

关键词： Car Model Circular Polarization Patch Antennas Rogers RT/Duroid 5880

Superheterodyne Amplification for Increase the Working Frequency

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Journal of Electromagnetic Analysis and Applications 2017年第3期9卷 43-52页

作者： Svetlana Koshevaya vladimir grimalsky Yuriy Kotsarenko Margarita Tecpoyotl Jesus Escobedo Autonomous State University of Morelos Cuernavaca Mexico

The amplification of microwaves in n-GaAs films has been widely studied. On the other hand, using nonlinear parametric effects in microwave, millimeter, and THz ranges has a large potential. In this paper the resonant nonlinear phenomena are investigated in active n-GaAs semiconductor and in films on its base. The phenomena are the nonlinear interactions of space charge waves, including the frequency multiplication and mixing, and the three-wave interaction between two THz electromagnetic waves and a single space charge wave. This three-wave interaction results in the superheterodyne amplification of THz waves. The electron velocity in GaAs is the nonlinear function of an external electric field. If the bias electric field is more E0>Ecrit ≈3Kv/cm , it is possible to obtain a negative differential mobility (NDM and space charge waves). The space charge waves have phase velocity of electrons equal to v0=v(E0), E0=v0/Lz , where v0 is the voltage, producing the bias electric field E0?in GaAs film. The superheterodyne amplification and the multiplication of microwaves are very promising for building active sensors in telecommunications system, radiometers, and radio telescopes. The superheterodyne mechanism has an advantage related to decreasing noise because of increasing of frequency in the process of amplification. It is used in the process of amplification of longitudinal space charge waves that in turn causes the transfer of energy from longitudinal wave into transverse one with increasing frequency. This is realized due to parametric coupling of two transverse waves and a single space charge wave in GaAs.

关键词： Space Charge Waves Superheterodyne Amplification

Experimental Analysis of Epoxy Resin as Antenna Radome

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通讯和计算机（中英文版） 2012年第11期9卷 1213-1217页

作者： J. G. vera-Dimas M. Tecpoyotl-Torres v. grimalsky S.v. Koshevaya J.A. Garcia-Limon Research Center of Engineering and Applied Sciences CIICAp UAEM. Cuernavaca Morelos Mexico University of the Sun. Postgraduate division in Industrial Engineering. Cuernavaca Morelos Mexico

In this research, experimental tests were realized in order to demonstrate the feasibility to use of epoxy resin as patch antenna radome. The interest in this material is due to its low cost and availability. In the fists group of tests, the interference produced by a piece of epoxy resin was analyzed. Three colors were chosen to determinate the color effect on the wave propagation. The use of color is desirable to hide the antenna geometry to the user for commercial purposes. The chosen color is irrelevant for the propagation of the electromagnetic wave. In the second group of tests, the measurements of parameter S21 were realized considering patch antennas with and without cover made of epoxy resin in order to analyze the effect of the cover on the patch antenna performance. The obtained results allow people to confirm the feasibility to use this material as patch antenna radome, because the lightly increasing in the waveband is enough to maintain the antenna performance in spite of the lightly operation frequency shift.

关键词：环氧树脂天线罩实验分析贴片天线实验测试波的传播色彩效果天线性能