scholarly journals PCB current identification based on near-field measurements using preconditioning and regularization

2016 ◽  
Vol 14 ◽  
pp. 121-127 ◽  
Author(s):  
Denis Rinas ◽  
Patrick Ahl ◽  
Stephan Frei
Keyword(s):  
Field Distribution ◽  
Current Distribution ◽  
Field Data ◽  
Near Field ◽  
Linear Equations ◽  
Field Measurements ◽  
Regularization Methods ◽  
Radiation Model ◽  
Observation Area ◽  
Source Current

Abstract. Radiated electromagnetic fields from a PCB can be estimated when the source current distribution is known. From a measured near-field distribution, the PCB source current distribution can be found. Accuracy depends on the measurement method and its limitations, the radiation model and the choice of the observation area. Many known methods are based on optimization algorithms for inverse problems that vary a set of elementary radiation sources and create a radiation model. However, apart from the time-consuming optimization process, such methods find one possible solution for a near-field distribution. As this distribution might not reflect the real current distribution, accuracy outside of near-field scan area can be low. Furthermore numerical problems can often be observed. Solving the given inverse problem with a system of linear equations and complex near-field data it can be very sensitive to noise. Regularization methods and an adjusted preconditioning can increase the accuracy. In this paper, an improved radiation model creation approach based on complex near-field data is presented. This approach is based on regularization methods and extended by current estimations from near-field data. Preconditioning is done considering some physical properties of the PCB and its possible current paths. Accuracy and stability of the method are investigated in the presence of noisy data.

scholarly journals Measurement of the Near Field Distribution of a Microwave Horn Using a Resonant Atomic Probe

2019 ◽  
Vol 9 (22) ◽  
pp. 4895 ◽  
Author(s):  
Jingxu Bai ◽  
Jiabei Fan ◽  
Liping Hao ◽  
Nicholas L. R. Spong ◽  
Yuechun Jiao ◽  
...  
Keyword(s):  
Field Distribution ◽  
Electric Fields ◽  
Microwave Field ◽  
Electric Field Distribution ◽  
Near Field ◽  
Field Measurements ◽  
Amplitude Distribution ◽  
Field Coupling ◽  
All Optical ◽  
Atomic Probe

We measure the near field distribution of a microwave horn with a resonant atomic probe. The microwave field emitted by a standard microwave horn is investigated utilizing Rydberg electromagnetically inducted transparency (EIT), an all-optical Rydberg detection, in a room temperature caesium vapor cell. The ground 6 S 1 / 2 , excited 6 P 3 / 2 , and Rydberg 56 D 5 / 2 states constitute a three-level system, used as an atomic probe to detect microwave electric fields by analyzing microwave dressed Autler–Townes (AT) splitting. We present a measurement of the electric field distribution of the microwave horn operating at 3.99 GHz in the near field, coupling the transition 56 D 5 / 2 → 57 P 3 / 2 . The microwave dressed AT spectrum reveals information on both the strength and polarization of the field emitted from the microwave horn simultaneously. The measurements are compared with field measurements obtained using a dipole metal probe, and with simulations of the electromagnetic simulated software (EMSS). The atomic probe measurement is in better agreement with the simulations than the metal probe. The deviation from the simulation of measurements taken with the atomic probe is smaller than the metal probe, improving by 1.6 dB. The symmetry of the amplitude distribution of the measured field is studied by comparing the measurements taken on either side of the field maxima.

Characterizing a GPR antenna system by near-field electric field measurements

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. A51-A55 ◽  
Author(s):  
Rita Streich ◽  
Jan van der Kruk
Keyword(s):  
Electric Field ◽  
Field Data ◽  
Near Field ◽  
Field Measurements ◽  
Input Voltage ◽  
Antenna System ◽  
Inversion Method ◽  
Migration Imaging ◽  
Imaging Algorithms ◽  
Electric Field Measurements

A method to determine current distributions on resistively loaded Wu-King-type antennas from sparse near-field measurements of the electric field is introduced. We use a parametric formulation of current flow and invert the measured data to determine the characteristic antenna parameters and input voltage wavelets that best explain the measured electric-field data. We compare modeled and measured electric-field data to show that our inversion method yields reasonable results and that our antenna model provides a means to correct for the effects of an antenna’s finite length in migration/imaging algorithms. By modifying the description of the current distribution, our method may be adapted for various antenna types.

Reply by the authors to the discussion by M. Zhdanov

Geophysics ◽  
1999 ◽  
Vol 64 (4) ◽  
pp. 1335-1335
Author(s):  
Yanping Guo, ◽  
Harvey W. Ko, ◽  
David M. White
Keyword(s):  
Field Distribution ◽  
Efficient Method ◽  
Near Field ◽  
Back Propagation ◽  
Field Measurements ◽  
Field Conditions ◽  
Diffusion Field ◽  
Inverse Source Problem ◽  
Surface Field ◽  
Surface Image

The work described in our paper is an inverse source problem using a back propagation approach to reconstruct the field distribution below the surface based on surface field measurements. The algorithm we developed is consistent with quasi‐static diffusion field conditions and uses spatial transforms to reconstruct the below surface image. The result is an efficient method of identifying the location and orientation of underground objects within the near field of excitation coils on the surface.

scholarly journals An Efficient Transformation Technique for the Direct Recovering of the Antenna Far-Field Pattern from Near-Field Measurements Collected along a Helix

2013 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
F. D'Agostino ◽  
F. Ferrara ◽  
C. Gennarelli ◽  
R. Guerriero ◽  
M. Migliozzi
Keyword(s):  
Electromagnetic Fields ◽  
Field Data ◽  
Near Field ◽  
Field Measurements ◽  
Field Pattern ◽  
Far Field ◽  
Transformation Technique ◽  
Computational Burden ◽  
Field Transformation ◽  
Far Field Pattern

A near-field to far-field transformation technique with helicoidal scanning for elongated antennas, which allows the evaluation of the antenna far-field pattern in any cut plane directly from a nonredundant number of near-field data without interpolating them, is developed in this paper. It is based on the nonredundant sampling representations of electromagnetic fields and employs a flexible source modelling suitable for long antennas to determine the number of helix turns. The number of near-field measurements on each turn is on the contrary dictated by the minimum cylinder rule, as in the classical cylindrical scanning, in order to reduce the computational burden and to simplify the scanning from the mechanical viewpoint. Some numerical and experimental results assessing the effectiveness of the proposed technique are reported.

scholarly journals Far-field to Near-field Data Relations for the Inverse Electromagnetic Scattering Problem

2021 ◽  
pp. 22-28
Author(s):  
Arnold Abramov ◽  
Yutao Yue
Keyword(s):  
Electromagnetic Scattering ◽  
Field Data ◽  
Near Field ◽  
Scattering Problem ◽  
Optimization Procedure ◽  
Field Measurements ◽  
The Other ◽  
Far Field ◽  
Dielectric Cylinder ◽  
Material Parameters

This paper considers (in general form) the problem of recovering information (size and material parameters) about the scattering object from far-field measurements. The order of solution and functions of each equation for the fields inside and outside the scattering object are discussed. Using well-known mathematical theorems, a simple equation has been derived that connects the far-field data on one side to the near-field data on the other side. Consequently, this equation has been used in an optimization procedure to find the parameters of the dielectric cylinder.

Sign in / Sign up

Export Citation Format

Share Document