scholarly journals Active meta-device for angular dispersion elimination of dual-polarizated transmission windows

2021 ◽  
Author(s):  
Hui Bai ◽  
Mingbao Yan ◽  
he wang ◽  
Jiafu Wang ◽  
Lin Zheng ◽  
...  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew J. Biggin ◽  
Richard K. Bono ◽  
Domenico G. Meduri ◽  
Courtney J. Sprain ◽  
Christopher J. Davies ◽  
...  

AbstractA defining characteristic of the recent geomagnetic field is its dominant axial dipole which provides its navigational utility and dictates the shape of the magnetosphere. Going back through time, much less is known about the degree of axial dipole dominance. Here we use a substantial and diverse set of 3D numerical dynamo simulations and recent observation-based field models to derive a power law relationship between the angular dispersion of virtual geomagnetic poles at the equator and the median axial dipole dominance measured at Earth’s surface. Applying this relation to published estimates of equatorial angular dispersion implies that geomagnetic axial dipole dominance averaged over 107–109 years has remained moderately high and stable through large parts of geological time. This provides an observational constraint to future studies of the geodynamo and palaeomagnetosphere. It also provides some reassurance as to the reliability of palaeogeographical reconstructions provided by palaeomagnetism.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Bilal Aghoutane ◽  
Mohammed El Ghzaoui ◽  
Hanan El Faylali

AbstractThe aim of this work consists in characterizing the Terahertz (THz) propagation channel in an indoor environment, in order to propose a channel model for THz bands. We first described a propagation loss model by taking into account the attenuation of the channel as a function of distance and frequency. The impulse response of the channel is then described by a set of rays, characterized by their amplitude, their delay and their phase. Apart from the frequency selective nature, path loss in THz band is also an others issue associated with THz communication systems. This work based on the conventional Saleh-Valenzuela (SV) model which is intended for indoor scenarios. In this paper, we have introduced random variables as Line of sight (LOS) component, and then merging it with the SV channel model to adopt it to the THz context. From simulation, we noted an important effect when the distance between the transmitter and the receiver change. This effect produces variations in frequency loss. The simulations carried out from this model show that to enhance the performance of THz system it is recommended to transmit information over transmission windows instead over the whole band.


2001 ◽  
Vol 9 (4) ◽  
pp. 200 ◽  
Author(s):  
B.K. Ann Ngoi ◽  
Krishnan Venkatakrishnan ◽  
L.E.N. Lim ◽  
B. Tan

1999 ◽  
Vol 16 (9) ◽  
pp. 1525 ◽  
Author(s):  
W. J. Alford ◽  
Russell J. Gehr ◽  
R. L. Schmitt ◽  
A. V. Smith ◽  
Gunnar Arisholm

Author(s):  
M. Heusinger ◽  
T. Flügel-Paul ◽  
K. Grabowski ◽  
D. Michaelis ◽  
U. D. Zeitner

2010 ◽  
Vol 2 (3) ◽  
pp. 319 ◽  
Author(s):  
Juan P. Torres ◽  
Martin Hendrych ◽  
Alejandra Valencia

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