High-frequency diffraction of electromagnetic waves by a circular aperture in an infinite plane conducting screen

1960 ◽  
Vol 8 (1) ◽  
pp. 27-36 ◽  
Author(s):  
S. Seshadri ◽  
T. Wu
Keyword(s):  
High Frequency ◽  
Electromagnetic Waves ◽  
Circular Aperture ◽  
Infinite Plane ◽  
Conducting Screen

Scattering of electromagnetic waves by hybrid waves in a two-electron-temperature plasma

1991 ◽  
Vol 46 (1) ◽  
pp. 99-106 ◽  
Author(s):  
S. K. Sharma ◽  
A. Sudarshan
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Lower Hybrid ◽  
Stimulated Scattering ◽  
Coupled Modes ◽  
Temperature Plasma ◽  
Electrostatic Perturbation

In this paper, we use the hydrodynamic approach to study the stimulated scattering of high-frequency electromagnetic waves by a low-frequency electrostatic perturbation that is either an upper- or lower-hybrid wave in a two-electron-temperature plasma. Considering the four-wave interaction between a strong high-frequency pump and the low-frequency electrostatic perturbation (LHW or UHW), we obtain the dispersion relation for the scattered wave, which is then solved to obtain an explicit expression for the growth rate of the coupled modes. For a typical Q-machine plasma, results show that in both cases the growth rate increases with noh/noc. This is in contrast with the results of Guha & Asthana (1989), who predicted that, for scattering by a UHW perturbation, the growth rate should decrease with increasing noh/noc.

Multiple scattering of ultra-high frequency electromagnetic waves by two plasma cylinders

2012 ◽  
Vol 111 (7) ◽  
pp. 073303 ◽  
Author(s):  
Wu Xiao-po ◽  
Shi Jia-ming ◽  
Wang Jia-chun ◽  
Yuan Zhong-cai ◽  
Xu Bo ◽  
...  
Keyword(s):  
Multiple Scattering ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Ultra High Frequency

scholarly journals Study Effect of Objects Orientation in the Mediums On GPR Signal Reflections Using FDTD Simulation

2018 ◽  
Vol 3 (11) ◽  
pp. 73-77
Author(s):  
Aye Mint Mohamed Mostapha ◽  
Gamil Alsharahi ◽  
Abdellah Driouach
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Ground Penetrating Radar ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Ground Surface ◽  
Propagation Path ◽  
Fdtd Simulation ◽  
Ground Penetrating ◽  
Dielectric Objects

Ground penetrating radar (GPR) is a very effective tool for detecting and identifying objects below the ground surface.  based on  the propagation and reflection of high-frequency electromagnetic waves. The GPR reflection can be affected by many things like the type of objects orientation, their shapes ..ect. The purpose of this paper is to  study by simulation the effect of objects orientation in two different mediums (dry and wet sand) on the GPR signal reflection using Reflexw software which is based on a numerical method known as finite difference in time domain (FDTD).  The simulations that have been realized included a conductor  and dielectric objects. The results obtained have led us to find that the propagation path, the reflection strength and the signal form change with the change of object orientation and nature. To confirm the validity of the results, we compared them with experimental results previously published by researchers under the same conditions.

Practical Considerations for Waveguide-Ballistic Thermal Energy Conversion

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Michael Wieckowski ◽  
Martin Margala
Keyword(s):  
Finite Element Method ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Finite Element Method Simulation ◽  
Electrical Energy ◽  
Heat Energy ◽  
Free Electrons ◽  
Thermal Energy Conversion ◽  
Metal Waveguide ◽  
Dc Potential

The potential of converting heat energy into electrical energy using a previously reported waveguide-ballistic device is presented. The interactions between incident electromagnetic waves and free electrons in a metal waveguide are analyzed with respect to their transport through a high-frequency ballistic rectifier using finite element method simulation. It was determined that the resulting conversion efficiency to a dc potential is approximately 6%, yielding a power density on the order of 30W∕m2.

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