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Wyszukujesz frazę "propagation distance" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Influence of optical Airy transform on non-diffracting propagation distance of finite energy Airy beams
Autorzy:
Chu, Xingchun
Liu, Rongjiang
Wang, Xiang
Han, Zhongxiang
Ni, Yanhui
Powiązania:
https://bibliotekanauki.pl/articles/2033885.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
physics optics
non-diffracting beam
finite energy Airy beam
non-diffracting propagation distance
optical Airy transform
Opis:
Finite energy Airy beams (FEAB) generated in laboratory have a short non-diffracting propagation distance (NDPD), which restricts its application in laser communication, laser detection and other fields. Effects of optical Airy transform (OAT) on NDPD of FEAB is analyzed. By comparing the theoretical formulas of the FEAB before and after the OAT, we find that when the transform parameter α of the OAT is larger than zero, the transverse scaling factor of the transformed FEAB is greater than that before the transformation, while the transformed exponential decay factor is smaller than that before the transformation. Using the Huygens–Fresnel diffractive integral, we derive the propagation formula of the transformed FEAB. Initial intensity distribution of FEAB before and after the OAT is compared. Propagation dynamics of the transformed FEAB with different α is numerically simulated and its NDPD is quantitatively evaluated. Results show that: with the increase of α, side lobes of the transformed FEAB increase, its main lobe and side lobes become wider than that before the transformation, and the inclination of the propagation trajectory decreases. When α is greater than half of the transverse scaling factor, the NDPD of the transformed FEAB increases rapidly.
Źródło:
Optica Applicata; 2021, 51, 4; 473-482
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Optimized Propagation Model based on Measurement Data for Indoor Environments
Autorzy:
Morocho-Yaguana, M.
Ludeňa-González, P.
Sandoval, F.
Poma-Vélez, B.
Erreyes-Dota, A.
Powiązania:
https://bibliotekanauki.pl/articles/308451.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
indoor
ITU model
log-distance model
loss measurement
one-slope model
path loss
propagation measurements
propagation models
radio propagation
Opis:
Propagation is an essential factor ensuring good coverage of wireless communications systems. Propagation models are used to predict losses in the path between transmitter and receiver nodes. They are usually defined for general conditions. Therefore, their results are not always adapted to the behavior of real signals in a specific environment. The main goal of this work is to propose a new model adjusting the loss coefficients based on empirical data, which can be applied in an indoor university campus environment. The Oneslope, Log-distance and ITU models are described to provide a mathematical base. An extensive measurement campaign is performed based on a strict methodology considering different cases in typical indoor scenarios. New loss parameter values are defined to adjust the mathematical model to the behavior of real signals in the campus environment. The experimental results show that the model proposed offers an attenuation average error of 2.5% with respect to the losses measured. In addition, comparison of the proposed model with existing solutions shows that it decreases the average error significantly for all scenarios under evaluation.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 2; 69-75
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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