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 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.

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.

Immobilization of Radionuclides on Iron Canister Material at Simulated Near-field Conditions

2008 ◽  
Author(s):  
Daqing Cui ◽  
Ylva Ranebo ◽  
Jeanett Low ◽  
Vincenzo Rondinella ◽  
Jinshan Pan ◽  
...  
Keyword(s):  
Near Field ◽  
Field Conditions

Practical Considerations in Compressed Spherical Near-Field Measurements

2019 ◽  
Author(s):  
Cosme Culotta-Lopez ◽  
Brett Walkenhorst ◽  
Quang Ton ◽  
Dirk Heberling
Keyword(s):  
Near Field ◽  
Field Measurements

scholarly journals Visualization of microwave near-field distribution in sodium chloride and glucose aqueous solutions by a thermo-elastic optical indicator microscope

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhirayr Baghdasaryan ◽  
Arsen Babajanyan ◽  
Levon Odabashyan ◽  
Jung-Ha Lee ◽  
Barry Friedman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Field Distribution ◽  
Near Field ◽  
Absorption Properties ◽  
Novel Approach ◽  
Concentration Changes ◽  
Biological Liquids ◽  
Optical Indicator ◽  
Distribution Intensity

AbstractIn this study, a new optical method is presented to determine the concentrations of NaCl and glucose aqueous solutions by using a thermo-elastic optical indicator microscope. By measuring the microwave near-field distribution intensity, concentration changes of NaCl and glucose aqueous solutions were detected in the 0–100 mg/ml range, when exposed to microwave irradiation at 12 GHz frequency. Microwave near-field distribution intensity decreased as the NaCl or glucose concentration increased due to the changes of the absorption properties of aqueous solution. This method provides a novel approach for monitoring NaCl and glucose in biological liquids by using a CCD sensor capable of visualizing NaCl and glucose concentrations without scanning.

scholarly journals Efficient Planar Near-field Measurements for Radiation Pattern Evaluation by a Warping Strategy

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Maria Antonia Maisto ◽  
Giovanni Leone ◽  
Adriana Brancaccio ◽  
Raffaele Solimene
Keyword(s):  
Radiation Pattern ◽  
Near Field ◽  
Field Measurements

Atomic 2D electric field imaging of a Yagi–Uda antenna near-field using a portable Rydberg-atom probe and measurement instrument

2020 ◽  
Vol 9 (5) ◽  
pp. 305-312
Author(s):  
Ryan Cardman ◽  
Luís F. Gonçalves ◽  
Rachel E. Sapiro ◽  
Georg Raithel ◽  
David A. Anderson
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Field Measurement ◽  
Near Field ◽  
Measurement Instrument ◽  
Rydberg Atom ◽  
Field Measurements ◽  
Atom Probe ◽  
Electric Field Measurement ◽  
Measurement Uncertainties

AbstractWe present electric field measurements and imaging of a Yagi–Uda antenna near-field using a Rydberg atom–based radio frequency electric field measurement instrument. The instrument uses electromagnetically induced transparency with Rydberg states of cesium atoms in a room-temperature vapor and off-resonant RF-field–induced Rydberg-level shifts for optical SI-traceable measurements of RF electric fields over a wide amplitude and frequency range. The electric field along the antenna boresight is measured using the atomic probe at a spatial resolution of ${\lambda }_{RF}/2$ with electric field measurement uncertainties below 5.5%, an improvement to RF measurement uncertainties provided by existing antenna standards.

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