scholarly journals Analysis of Bistatic Scattering of Electromagnetic Waves by Melting Layer

2011 ◽  
Vol 1 ◽  
pp. 41-43
Author(s):  
Binay Kumar Jha
Keyword(s):  
Electromagnetic Waves ◽  
Mie Theory ◽  
Propagation Path ◽  
Bistatic Radar ◽  
Interference Effects ◽  
Melting Layer ◽  
Bistatic Scattering ◽  
Rain Rates ◽  
The Impact

In this communication bistatic scattering of electromagnetic waves by the melting layer of precipitation has been presented. The bistatic radar reflectivities have been formulated and can be computed at 1- 100GHz by applying the Mie theory for raindropsize distributions at rain rates below 12.5mm/h. It is very important to study the integrated interference effects all along the propagation path as well as of greatest interest for evaluating the impact of the melting layer effects on bistatic interference for communications.Key words: Bistatic scattering; Interference; Hydrometeors; Melting layerThe Himalayan Physics Vol.1, No.1, May, 2010Page: 41-43Uploaded Date: 28 July, 2011

scholarly journals Joint UAV channel modeling and power control for 5G IoT networks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Xiuhua Fu ◽  
Tian Ding ◽  
Rongqun Peng ◽  
Cong Liu ◽  
Mohamed Cheriet
Keyword(s):  
Energy Efficiency ◽  
Power Control ◽  
Channel Model ◽  
Path Loss ◽  
Channel Modeling ◽  
Signal Propagation ◽  
Spectrum Efficiency ◽  
Propagation Path ◽  
Control Factor ◽  
The Impact

AbstractThis paper studies the communication problem between UAVs and cellular base stations in a 5G IoT scenario where multiple UAVs work together. We are dedicated to the uplink channel modeling and the performance analysis of the uplink transmission. In the channel model, we consider the impact of 3D distance and multi-UAVs reflection on wireless signal propagation. The 3D distance is used to calculate the path loss, which can better reflect the actual path loss. The power control factor is used to adjust the UAV's uplink transmit power to compensate for different propagation path losses, so as to achieve precise power control. This paper proposes a binary exponential power control algorithm suitable for 5G networked UAV transmitters and presents the entire power control process including the open-loop phase and the closed-loop phase. The effects of power control factors on coverage probability, spectrum efficiency and energy efficiency under different 3D distances are simulated and analyzed. The results show that the optimal power control factor can be found from the point of view of energy efficiency.

scholarly journals Monitoring the Impact of Electromagnetic Waves on Yield and Quality in Maize

2011 ◽  
Vol 68 (1) ◽  
Author(s):  
Florin IMBREA ◽  
Branko MARINCOVIC ◽  
Valeriu TABĂRĂ ◽  
PAUL PÎRŞAN ◽  
Gheorghe DAVID ◽  
...  
Keyword(s):  
Protein Content ◽  
Quality Indicators ◽  
Electromagnetic Waves ◽  
Starch Content ◽  
New Technology ◽  
Low Frequency ◽  
Cultivation Method ◽  
Yield And Quality ◽  
The Impact ◽  
Starch Yield

Experimenting new technology of cultivating maize is an important step forward in order to optimise the yielding capacity if a crop that ranks second among crops cultivated worldwide and first among crops cultivated in Romania. Using low frequency radiations to stimulate yield and quality in maize allows increases in yield between 10 and 15% compared to the classical cultivation method and an improvement of the quality indicators (protein content increased with 6-11% determining an increase of the protein yield per ha; starch content increased with 7-14%, which also determined an increase of the starch yield per ha; while fat content, another indicator we monitored, increased with 2-6%).

scholarly journals Observation of 2nd Schumann eigenmode on Titan's surface

2013 ◽  
Vol 3 (1) ◽  
pp. 157-192 ◽  
Author(s):  
C. Béghin ◽  
G. Wattieaux ◽  
R. Grard ◽  
M. Hamelin ◽  
J. P. Lebreton
Keyword(s):  
Electromagnetic Waves ◽  
Low Frequency ◽  
Amplitude Distribution ◽  
Data Conversion ◽  
Schumann Resonance ◽  
Huygens Probe ◽  
Atmospheric Structure ◽  
The Impact ◽  
Space Wave ◽  
Expected Signal

Abstract. This works presents the results obtained from an updated data analysis of the observations of Extremely Low Frequency (ELF) electromagnetic waves performed with the HASI-PWA (Huygens Atmospheric Structure and Permittivity, Wave and Altimetry) instrumentation after Huygens Probe landing on Titan surface in January 2005. The most significant signals observed at around 36 Hz throughout the descent in the atmosphere have been extensively analyzed for several years, and subsequently interpreted as the signature of a Schumann resonance, although the latter exhibits atypical peculiarities compared with those known on Earth. The usual depicting methods of space wave data used so far could not allow retrieving the presence of weak signals when Huygens was at rest for 32 min on Titan's surface. Whereas the expected signal seems hidden within the instrumental noise, we show that a careful statistical analysis of the amplitude distribution of the 418 spectral density samples of the 36 Hz line reveals abnormal characteristics compared to other frequencies. This behavior is shown to occur under propitious circumstances due to the characteristics of the onboard data conversion processes into digital telemetry counts, namely 8-bit dynamic after logarithm compression of the DFT (Discrete Fourier Transform) of ELF waveforms. Since this phenomenon is observed only at the frequency bin around 36 Hz, we demonstrate that the Schumann resonance, seen in the atmosphere within the same band, is still present on the surface, albeit with a much smaller amplitude compared to that measured before and a few seconds after the impact, because the electric dipole is thought to have been stabilized ten seconds later almost horizontally until the end of the measurements.

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.

Compact Dual-Passband Three-Dimensional FSS with Good Angular Stability and Both-Side Fast Roll-Off Characteristics

2021 ◽  
Vol 36 (6) ◽  
pp. 664-669
Author(s):  
Zhengyong Yu ◽  
Baozhu Li ◽  
Shenggao Ding ◽  
Wanchun Tang
Keyword(s):  
Electromagnetic Waves ◽  
Electromagnetic Coupling ◽  
Three Dimensional ◽  
Frequency Selective Surface ◽  
Resonant Mode ◽  
Unit Cell ◽  
Angular Stability ◽  
Propagation Path ◽  
Annular Slot ◽  
Parallel Plate Waveguide

A compact dual-passband three-dimensional (3D) frequency selective surface (FSS) is proposed based on multiple square coaxial waveguides (SCWs), which exhibits good angular stability and both-side fast roll-off characteristics. The unit cell of the proposed 3D FSS is composed of one parallel plate waveguide (PPW) propagation path and two SCW propagation paths. By etching a centered annular slot, each SCW path forms two identical short SCWs. Each short SCW inherently generates one square slot resonance. In each SCW path, on the account of electromagnetic coupling between two square slot resonators provided by two short SCWs, the square slot resonant mode will split into even-/odd-resonant modes. Accordingly, each SCW path can provide a flat second-order passband with two transmission poles. Due to the reflection and out of phase of electromagnetic waves, four transmission zeros located at both sides of the passbands are introduced for high frequency selectivity, realizing both-side fast roll-off performances. In order to explain the operating principle, the electric-field distributions at transmission-zero/pole frequencies are investigated. Finally, an FSS prototype is fabricated and measured, and the results exhibit good angular stability for both TE and TM polarizations under incident angles from 0° to 60°. In addition, the proposed 3D FSS has a compact unit cell.

scholarly journals Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 729 ◽  
Author(s):  
Kazimierz Gut
Keyword(s):  
Refractive Index ◽  
Output Signal ◽  
Propagation Constant ◽  
Low Cost ◽  
Waveguide Layer ◽  
Propagation Path ◽  
Slab Waveguide ◽  
Polymer Waveguides ◽  
Materials Used ◽  
The Impact

A model and the waveguide parameters of a broadband, polymer-based slab waveguide difference interferometer is presented in this paper. The parameters were determined based on knowledge of the dispersion in the structure materials used to fabricate the waveguide. The impact of the waveguide layer thickness, propagation path length, and change in the waveguide cover refractive index on the output signal from the system was determined. It has been shown that the direction of the maximum shifting is determined by the thickness of the waveguide layer. A relationship describing the shift in the signal extrema for a change in the waveguide cover refractive index was derived. The results show that the use of a propagation constant simplifies the description of the interferometer. Polymer waveguides, although they have a small contrast in refractive indices, allow for large shifts in the maxima of the signal. The determined shifts in the output signal extrema for polymer waveguides are comparable, and these shifts are larger for some waveguide thicknesses compared to waveguides based on Si3N4.

scholarly journals Quantum interference effects in multi-channel correlated tunneling structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
N. S. Maslova ◽  
V. N. Mantsevich ◽  
V. N. Luchkin ◽  
V. V. Palyulin ◽  
P. I. Arseyev ◽  
...  
Keyword(s):  
Coulomb Interaction ◽  
Quantum Interference ◽  
Tunneling Conductance ◽  
Interference Effects ◽  
Impurity Atoms ◽  
Occupation Numbers ◽  
Fano Interference ◽  
Main Effect ◽  
The Impact ◽  
Intermediate System

AbstractIn multi-channel tunneling systems quantum interference effects modify tunneling conductance spectra due to Fano effect. We investigated the impact of Hubbard type Coulomb interaction on tunneling conductance spectra for the system formed by several interacting impurity atoms or quantum dots localised between the contact leads. It was shown that the Fano shape of tunneling conductance spectra strongly changes in the presence of on-site Coulomb interaction between localised electrons in the intermediate system. The main effect which determines the shape of the tunneling peaks could be not Fano interference but mostly nonequilibrium dependence of the occupation numbers on bias voltage.

scholarly journals On the multipath effects due to wall reflections for wave reception in a corner

Noise Mapping ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 41-64
Author(s):  
Luiz Manuel Braga da Costa Campos ◽  
Manuel José dos Santos Silva ◽  
Agostinho Rui Alves da Fonseca
Keyword(s):  
Electromagnetic Waves ◽  
Double Series ◽  
Two Dimensions ◽  
Reflection Coefficients ◽  
Urban Air ◽  
Interference Effects ◽  
Direct Signal ◽  
Total Signal ◽  
Spectral Bands ◽  
Multipath Effects

Abstract Multipath effects occur when receiving a wave near a corner, for example, the noise of an helicopter or an aircraft or a drone or other forms of urban air mobility near a building, or a telecommunications receiver antenna near an obstacle. The total signal received in a corner consists of four parts: (i) a direct signal from source to observer; (ii) a second signal reflected on the ground; (iii) a third signal reflected on the wall; (iv) a fourth signal reflected from both wall and ground. The problem is solved in two-dimensions to specify the total signal, whose ratio to the direct signal specifies the multipath factor. The amplitude and phase of the multipath factor are plotted as functions of the frequency over the audible range, for various relative positions of observer and source, and for several combinations of the reflection coefficients of the ground and wall. It is shown that the received signal consists of a double series of spectral bands, in other words: (i) the interference effects lead to spectral bands with peaks and zeros; (ii) the successive peaks also go through zeros and “peaks of the peaks”. The results apply not only to sound, but also to other waves, e.g., electromagnetic waves using the corresponding frequency band and reflection factors.

The impact of assimilating radar-estimated rain rates on simulation of precipitation in the 17–18 July 1996 Chicago floods

2010 ◽  
Vol 27 (2) ◽  
pp. 195-210 ◽  
Author(s):  
Xingbao Wang ◽  
M. K. Yau ◽  
B. Nagarajan ◽  
Luc Fillion
Keyword(s):  
Rain Rates ◽  
The Impact
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