Near Field Pressure Measurement around Three Dimensional Free Flight Models

AbstractThis paper is concerned with the inverse scattering problem for the three-dimensional Maxwell equations in bi-anisotropic periodic structures. The inverse scattering problem aims to determine the shape of bi-anisotropic periodic scatterers from electromagnetic near-field data at a fixed frequency. The factorization method is studied as an analytical and numerical tool for solving the inverse problem. We provide a rigorous justification of the factorization method which results in the unique determination and a fast imaging algorithm for the periodic scatterer. Numerical examples for imaging three-dimensional periodic structures are presented to examine the efficiency of the method.

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A Fast Three-Dimensional Near-Field Imaging Algorithm for MIMO Cross-Array

2020 13th UK-Europe-China Workshop on Millimetre-Waves and Terahertz Technologies (UCMMT) ◽

10.1109/ucmmt49983.2020.9296053 ◽

2020 ◽

Author(s):

Feifan Wang ◽

Qi Yang ◽

Bin Deng ◽

Ye Zhang ◽

Hongqiang Wang

Keyword(s):

Near Field ◽

Three Dimensional ◽

Imaging Algorithm ◽

Near Field Imaging ◽

Field Imaging

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Three-Dimensional Finite-Difference Time-Domain Method Modeling of Nanowire Optical Probe

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.602-605.3359 ◽

2014 ◽

Vol 602-605 ◽

pp. 3359-3362

Author(s):

Chun Li Zhu ◽

Jing Li

Keyword(s):

Finite Difference ◽

Time Domain ◽

Finite Difference Time Domain ◽

Incident Light ◽

Near Field ◽

Three Dimensional ◽

Polarization Direction ◽

Near Field Imaging ◽

Difference Time ◽

Field Imaging

In this paper, output near fields of nanowires with different optical and structure configurations are calculated by using the three-dimensional finite-difference time-domain (3D FDTD) method. Then a nanowire with suitable near field distribution is chosen as the probe for scanning dielectric and metal nanogratings. Scanning results show that the resolution in near-field imaging of dielectric nanogratings can be as low as 80nm, and the imaging results are greatly influenced by the polarization direction of the incident light. Compared with dielectric nanogratings, metal nanogratings have significantly enhanced resolutions when the arrangement of gratings is perpendicular to the polarization direction of the incident light due to the enhancement effect of the localized surface plasmons (SPs). Results presented here could offer valuable references for practical applications in near-field imaging with nanowires as optical probes.

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A Numerically Efficient Method for Analysis of Very Large Articulated Floating Structures

Journal of Ship Research ◽

10.5957/jsr.1998.42.3.174 ◽

1998 ◽

Vol 42 (03) ◽

pp. 174-186

Author(s):

C. J. Garrison

Keyword(s):

Hydrodynamic Interaction ◽

Near Field ◽

Three Dimensional ◽

Computational Effort ◽

Floating Structure ◽

Complete Structure ◽

Field Interaction ◽

Floating Structures ◽

Computing Effort ◽

The Individual

A method is presented for evaluation of the motion of long structures composed of interconnected barges, or modules, of arbitrary shape. Such structures are being proposed in the construction of offshore airports or other large offshore floating structures. It is known that the evaluation of the motion of jointed or otherwise interconnected modules which make up a long floating structure may be evaluated by three dimensional radiation/diffraction analysis. However, the computing effort increases rapidly as the complexity of the geometric shape of the individual modules and the total number of modules increases. This paper describes an approximate method which drastically reduces the computational effort without major effects on accuracy. The method relies on accounting for hydrodynamic interaction effects between only adjacent modules within the structure rather than between all of the modules since the near-field interaction is by far the more important. This approximation reduces the computational effort to that of solving the two-module problem regardless of the total number of modules in the complete structure.

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Near-field optical investigation of three-dimensional photonic crystals

Physical Review E ◽

10.1103/physreve.68.015601 ◽

2003 ◽

Vol 68 (1) ◽

Cited By ~ 21

Author(s):

E. Flück ◽

N. F. van Hulst ◽

W. L. Vos ◽

L. Kuipers

Keyword(s):

Photonic Crystals ◽

Near Field ◽

Three Dimensional ◽

Optical Investigation

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Seismic Vertical Component Effects on the Pathology of a Historical Structure, Xana, Located in Greece

Frontiers in Built Environment ◽

10.3389/fbuil.2021.666840 ◽

2021 ◽

Vol 7 ◽

Author(s):

Vasiliki Terzi ◽

Asimina Athanatopoulou

Keyword(s):

Seismic Analysis ◽

Near Field ◽

Three Dimensional ◽

Vertical Component ◽

Element Model ◽

Material Behavior ◽

Initial State ◽

Tensile Cracks ◽

First Case ◽

Three Dimensional Finite Element

The present study aims to investigate the effects of the seismic vertical component on the pathology of Xana monument which is a typical caravanserai, constructed circa 1375–1385 and is located in the archeological site of the municipality of Trainapoulis, Greece. The monument’s plan is rectangular and the three-leaf masonry circumferential walls support a hemicylindrical dome constructed by bricks and mortar. The structure consisted of two consecutive parts: one for the travelers and one for the animals. Nowadays, the triangular roof, that covered the structure, and the first part of the monument do not exist. Xana suffers tensile cracks along the interior surface of the dome, a vertical fracture located on the northern wall and vertical tensile cracks located at the openings. A three-dimensional finite element model of the initial state of Xana is constructed. Non-linear material behavior is taken into account as well as soil-structure interaction effects. An adequate number of near-field earthquake events has been used, taking into account that they are related to significant vertical components. The structural seismic analysis is conducted for two cases. The first case refers to the action of the two horizontal-component of ground motions while the second one takes into account the three translational seismic components. The pathology estimation reveals important information concerning the structural effects due to vertical accelerations.

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Installation Uncertainty of Field Level Calculation around a Base Station Antenna

Journal of Communications Software and Systems ◽

10.24138/jcomss.v3i2.260 ◽

2007 ◽

Vol 3 (2) ◽

pp. 115

Author(s):

Antonio Šarolić ◽

Borivoj Modlic

Keyword(s):

Hazard Analysis ◽

Near Field ◽

Three Dimensional ◽

Real Life ◽

Base Station ◽

Radiation Hazard ◽

Specific Situation ◽

Field Calculation ◽

Single Antenna ◽

Level Calculation

In the near field, the antenna pattern provided by the antenna manufacturer is generally not applicable, or shouldbe considered with caution, even for the single antenna in free space. In the real life, antenna is often surrounded by other conductive objects in the immediate vicinity. These objects tend to distort the antenna radiation pattern. Since the electromagnetic field calculation for the coverage or radiation hazard analysis depends on the three-dimensional antenna gain, this effect should be taken into account. This paper suggests the use of "installation uncertainty" that should be added to the field calculation. The amount of this quantity depends on the installation geometry and can be calculated numerically for a specific situation. This paper shows the results of numerical calculations for some typical antenna installation geometries.

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