Characterization of a flat plate antenna for OAM generation in the millimeter frequency band

Author(s):  
R. Niemiec ◽  
C. Brousseau ◽  
K. Mahdjoubi ◽  
O. Emile ◽  
A. Menard
2014 ◽  
Vol 13 ◽  
pp. 1011-1014 ◽  
Author(s):  
R. Niemiec ◽  
C. Brousseau ◽  
K. Mahdjoubi ◽  
O. Emile ◽  
A. Menard

1988 ◽  
Vol 22 (7) ◽  
pp. 1461-1468 ◽  
Author(s):  
Kenneth E. Noll ◽  
Kenneth Y.P. Fang ◽  
Laura A. Watkins
Keyword(s):  

Author(s):  
Katsumasa Miyazaki ◽  
Kunio Hasegawa ◽  
Koichi Saito

The fitness-for-service codes require the characterization of non-aligned multiple flaws for flaw evaluation, which is performed using a flaw proximity rule. Worldwide, almost all such codes provide their own proximity rule, often with unclear technical bases of the application of proximity rule to ductile or fully plastic fracture. In particular, the effect of flaw dimensions of multiple surface flaws on fully plastic fracture of non-aligned multiple flaws had not been clear. To clarify the effect of the difference of part through-wall and through-wall flaws on the behavior of fully plastic fracture, the fracture tests of flat plate specimens with non-aligned multiple part through-wall flaws were conducted. When the flaw depth a was shallow with 0.4 in ratio of a to thickness t, the maximum load Pmax occurred at penetration of multiple flaws and the effect of vertical distance of non-aligned multiple flaws H on Pmax was not so significant. However, when flaw depth was deep with 0.8 in a/t, Pmax occurred after penetration of flaws and the effect of H on Pmax could be seen clearly. It was judged that the through-wall flaw tests were appropriate for discussion of the effect of H on Pmax and the alignment rule of multiple flaws. In addition, in order to clarify the appropriate length parameter to estimate Pmax of test specimens with dissimilar non-aligned through-wall multiple flaws, the fracture tests of plate specimens were also conducted. The effect of different flaw length on Pmax was discussed with maximum, minimum and averages of dissimilar non-aligned multiple flaw lengths. Experimental results showed that the maximum length lmax would be an appropriate length parameter to estimate Pmax, when the non-aligned multiple through-wall flaws were dissimilar.


Author(s):  
Azar Maalouf ◽  
Ronan Gingat ◽  
Vincent Laur

This study examines K-band rectangular waveguide terminations with three-dimensional (3D)-printed loads, and proposes an Asymmetrical Tapered Wedge topology. This geometry shows a good tradeoff between microwave performance and 3D-printing issues (printing directions and support material requirements), thus improving noticeably the reproducibility of the devices. The effect of the density of the 3D-printed load on the reflection parameter of the termination was investigated. Even for a low density, reflection level remained below −27.5 dB between 18 and 26.5 GHz. Reproducibility was demonstrated by the characterization of six loads that were 3D printed under the same conditions. Measurements demonstrate that a maximum reflection parameter level of −33.5 dB can be ensured over the whole frequency band without any post-machining of the 3D-printed devices.


Author(s):  
Mehdi Ferhat ◽  
Fares Bennai ◽  
Badreddine Ratni ◽  
Eric Vourch ◽  
Kamilia Abahri ◽  
...  
Keyword(s):  

2018 ◽  
Vol 19 (5) ◽  
pp. 503
Author(s):  
Amar Zerrout ◽  
Ali Khelil ◽  
Larbi Loukarfi

This study is an experimental and numerical analysis of the influence from changes in the conditions of inputs temperature and velocity on the behavior thermal and dynamic of a multi-jet swirling system impacting a flat plate. The experimental device comprising three diffusers arranged in line, of diameter D aloof 2D between the axes of their centers, impinging the plate perpendicularly at an impact height H = 6D. The swirl is obtained by a generator (swirl) of composed 12 fins arranged at 60° relative to the vertical placed just at the exit of the diffuser. By imposing the temperature and velocity for three input conditions with three studied configurations. The paper deals with find the configuration that optimizes the best thermal homogenization. The results show that the configuration having an equilibrated inlet temperature (T, T, T) is derived from a good temperature distribution on the baffle wall and a better thermal transfer from the plate. The system was numerically simulated by the fluent code by using the turbulence model (k–ε). This last has yielded results accorded to those experimental results.


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