The optical near-field speckles and their first order statistics on the basis of the integral equations of electromagnetic field

2004 ◽  
Vol 47 (3) ◽  
pp. 365
Author(s):  
Chuanfu CHENG
Keyword(s):  
Electromagnetic Field ◽  
Order Statistics ◽  
Integral Equations ◽  
Near Field ◽  
First Order

scholarly journals Numerical solution of the integral equations of the electromagnetic field in geosteering problems

2021 ◽  
Vol 1715 ◽  
pp. 012028
Author(s):  
A.V. Bondarenko ◽  
N. N. Velker ◽  
D.Yu. Kushnir ◽  
G.V. Dyatlov ◽  
Yu.A. Dashevsky
Keyword(s):  
Electromagnetic Field ◽  
Numerical Solution ◽  
Integral Equations

Modeling of First-Order Statistics of the MIMO Dual Polarized Channel at 2 GHz for Land Mobile Satellite Systems Under Tree Shadowing

2014 ◽  
Vol 62 (10) ◽  
pp. 5410-5415 ◽  
Author(s):  
Charilaos Kourogiorgas ◽  
Milan Kvicera ◽  
Dimitrios Skraparlis ◽  
Tomas Korinek ◽  
Vasileios K. Sakarellos ◽  
...  
Keyword(s):  
Order Statistics ◽  
Satellite Systems ◽  
First Order ◽  
Dual Polarized ◽  
Mobile Satellite ◽  
Mobile Satellite Systems

Near-field mapping of the electromagnetic field in confined photon geometries

2002 ◽  
Vol 66 (11) ◽  
Author(s):  
V. Zhuk ◽  
D.V. Regelman ◽  
D. Gershoni ◽  
M. Bayer ◽  
J.P. Reithmaier ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Near Field ◽  
Field Mapping

scholarly journals Dynamic near-field microwave diagnostics of lungs.

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
L.A. Bokeria ◽  
◽  
T.T. Kakuchaya ◽  
A.M. Kuular ◽  
Ye.S. Maksimovitch ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Inverse Problems ◽  
Integral Equations ◽  
Near Field ◽  
Experimental Studies ◽  
Heart Activity ◽  
Blood Content ◽  
Air Content ◽  
Microwave Diagnostics ◽  
Biomedical Diagnostics

Results of theoretical and experimental studies of the method of the near-field microwave tomography of the thorax are presented. Integral equations of inverse tomography problem of 3D blood- and air content inhomogeneities by data of multisensory measurements are obtained. Methods of air and blood content profiling in processes of breathing and heart activity by data of bistatic measurements of the scattered signal are proposed and solving algorithms of inverse problems are studied in the numerical simulation. Multifrequency and pulse measurements of scattered signals are carried out in processes of cardiorespiratory activity. By data of bistatic measurements of scattered signals parameters from the thorax, profiling relative air- and blood content profiles has been realized. Application possibilities of the method in the biomedical diagnostics are considered.

scholarly journals ВОССТАНОВЛЕНИЕ КОГЕРЕНТНЫХ ИЗОБРАЖЕНИЙ ПОВЕРХНОСТЕЙ В ЗОНЕ ФРЕНЕЛЯ МЕТОДАМИ МНОГОКАНАЛЬНОЙ ОБРАБОТКИ СИГНАЛОВ

2018 ◽  
pp. 97-102
Author(s):  
Валерий Константинович Волосюк ◽  
Семён Сергеевич Жила ◽  
Глеб Сергеевич Черепнин ◽  
Эдуард Алексеевич Цернэ
Keyword(s):  
Electromagnetic Field ◽  
Phase Distribution ◽  
Near Field ◽  
Delta Function ◽  
Basic Function ◽  
Ambiguity Function ◽  
Good Resolution ◽  
Fresnel Region ◽  
Coherent Image ◽  
Multichannel Signal Processing

The generalized structure of the electromagnetic field in the registration area is considered in the case of the solution of problems of remote sensing of the underlying surfaces. Examples of the existing radar and optical coherent devices are given. Analytical expressions for the electromagnetic field in the reception area when sounding is carried out in a near-field Fresnel region, in the assumption that the size of the field of registration and radiation is considerably less than a distance between them, are concretized. It is shown the main operations that are necessary for the recovery of coherent images in a near-field Fresnel region by the methods of multichannel signal processing. Research shows that as the amplitude-phase distribution of the registration field is necessary to choose the classical basic function of Fresnel transformation with the reversed sign in the exponent power. Formally, in an infinite range, the Fresnel transform is invertible, i.e. in the ideal case, the function can be completely restored. However physically to Fresnel's region satisfies area with finite sizes. From the analysis of the obtained operations over the received field, it follows that the radar or optical system forms an estimate of the coherent image in the form of a convolution of a true image of the underlying surface with an ambiguity function. Generally, this function contains two multipliers, one of which determines the resolution of recovery of the coherent image. In that specific case, when the linear sizes of the field of registration go to infinity, ambiguity function takes a form of delta function and the required image can be restored without distortions. It is offered to determine resolution by the width between first zeros of ambiguity function. For rectangular area ambiguity function has the form of two sinc functions which width is directly proportional to wavelength, to the height of sounding and is inversely proportional to the linear sizes of receiving area on the corresponding coordinates. Finally, it is mentioned that for the higher-quality coherent imaging with good resolution by the same receiving area it is necessary to perform scanning and movement in space

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