scholarly journals Near-Field Imaging of Interior Cavities

2015 ◽  
Vol 17 (2) ◽  
pp. 542-563 ◽  
Author(s):  
Peijun Li ◽  
Yuliang Wang
Keyword(s):  
Inverse Problem ◽  
Near Field ◽  
Boundary Value ◽  
Power Series Expansion ◽  
Scattering Data ◽  
Cavity Surface ◽  
Near Field Imaging ◽  
Smooth Perturbation ◽  
Novel Method ◽  
Explicit Relation

AbstractA novel method is developed for solving the inverse problem of reconstructing the shape of an interior cavity. The boundary of the cavity is assumed to be a small and smooth perturbation of a circle. The incident field is generated by a point source inside the cavity. The scattering data is taken on a circle centered at the source. The method requires only a single incident wave at one frequency. Using a transformed field expansion, the original boundary value problem is reduced to a successive sequence of two-point boundary value problems and is solved in a closed form. By dropping higher order terms in the power series expansion, the inverse problem is linearized and an explicit relation is established between the Fourier coefficients of the cavity surface function and the total field. A nonlinear correction algorithm is devised to improve the accuracy of the reconstruction. Numerical results are presented to show the effectiveness of the method and its ability to obtain subwavelength resolution.

Near Field EMC Scanning Method Based on an E-Field Collapse

2015 ◽  
Author(s):  
Jeff Dunnihoo ◽  
Pasi Tamminen ◽  
Toni Viheriäkoski
Keyword(s):  
Near Field ◽  
Electronic Systems ◽  
Inexpensive Method ◽  
Scanning Method ◽  
Field Information ◽  
Novel Method ◽  
Near Field Scanning

Abstract In this study we present a novel method to use a field collapse method together with fully automated near field scanning equipment to construct E- and H-field information of a system during transient ESD events. This inexpensive method provides an alternative way for system designers to validate and analyze the EMC/ESD capability of electronic systems without TLP pulsers, ESD simulators, or precision inductive current probes.

scholarly journals Efficient Near-Field Imaging Using Cylindrical MIMO Arrays

2021 ◽  
pp. 1-1
Author(s):  
Shiyong Li ◽  
Shuoguang Wang ◽  
Moeness G. Amin ◽  
Guoqiang Zhao
Keyword(s):  
Near Field ◽  
Near Field Imaging ◽  
Mimo Arrays ◽  
Field Imaging

scholarly journals Stability of the Non-abelian X-ray Transform in Dimension $$\ge 3$$

2021 ◽  
Author(s):  
Jan Bohr
Keyword(s):  
Stability Estimate ◽  
Scattering Data ◽  
Regularity Conditions ◽  
Uniform Bounds ◽  
Ray Transform ◽  
Shallow Layer ◽  
Matrix Potential ◽  
Novel Method ◽  
Statistical Consistency ◽  
Appl Math

AbstractNon-abelian X-ray tomography seeks to recover a matrix potential $$\Phi :M\rightarrow {\mathbb {C}}^{m\times m}$$ Φ : M → C m × m in a domain M from measurements of its so-called scattering data $$C_\Phi $$ C Φ at $$\partial M$$ ∂ M . For $$\dim M\ge 3$$ dim M ≥ 3 (and under appropriate convexity and regularity conditions), injectivity of the forward map $$\Phi \mapsto C_\Phi $$ Φ ↦ C Φ was established in (Paternain et al. in Am J Math 141(6):1707–1750, 2019). The present article extends this result by proving a Hölder-type stability estimate. As an application, a statistical consistency result for $$\dim M =2$$ dim M = 2 (Monard et al. in Commun Pure Appl Math, 2019) is generalised to higher dimensions. The injectivity proof in (Paternain et al. in Am J Math 141(6):1707–1750, 2019) relies on a novel method by Uhlmann and Vasy (Invent Math 205(1):83–120, 2016), which first establishes injectivity in a shallow layer below $$\partial M$$ ∂ M and then globalises this by a layer stripping argument. The main technical contribution of this paper is a more quantitative version of these arguments, in particular, proving uniform bounds on layer depth and stability constants.

Ultra-Wide Band Near-Field Imaging System

2007 ◽  
Author(s):  
Anatoliy O. Boryssenko ◽  
Christophe Craeye ◽  
Daniel H. Schaubert
Keyword(s):  
Imaging System ◽  
Near Field ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Near Field Imaging ◽  
Field Imaging

A metal-dielectric antenna for terahertz near-field imaging

2005 ◽  
Vol 98 (1) ◽  
pp. 014910 ◽  
Author(s):  
N. Klein ◽  
P. Lahl ◽  
U. Poppe ◽  
F. Kadlec ◽  
P. Kužel
Keyword(s):  
Near Field ◽  
Dielectric Antenna ◽  
Near Field Imaging ◽  
Field Imaging

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

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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