Computation of Near-Field and Far-Field Radiation Characteristics of Acoustic Transducers for Underwater Acoustic Imaging

2020 ◽  
Vol 10 (3) ◽  
pp. 145
Author(s):  
L. S. Praveen ◽  
Govind R. Kadambi ◽  
S. Malathi ◽  
Preetham Shankapal
Keyword(s):  
Near Field ◽  
Acoustic Imaging ◽  
Far Field ◽  
Radiation Characteristics ◽  
Underwater Acoustic ◽  
Acoustic Transducers ◽  
Field Radiation

scholarly journals Scattering centers modeling of non-anechoic measurement environments

2012 ◽  
Vol 10 ◽  
pp. 69-73 ◽  
Author(s):  
K. A. Yinusa ◽  
C. H. Schmidt ◽  
T. F. Eibert
Keyword(s):  
Near Field ◽  
Field Measurements ◽  
Field Pattern ◽  
Far Field ◽  
Scattering Centers ◽  
Field Transformation ◽  
Field Radiation ◽  
Echo Suppression ◽  
Multipath Signals ◽  
Far Field Pattern

Abstract. Near-field measurements are established techniques to obtain the far-field radiation pattern of an Antenna Under Test via near-field measurements and subsequent near-field far-field transformation. For measurements acquired in echoic environments, additional post-processing is required to eliminate the effects of multipath signals in the resulting far-field pattern. One of such methods models the measurement environment as a multiple source scenario whereby the collected near-field data is attributed to the AUT and some scattering centers in the vicinity of the AUT. In this way, the contributions of the AUT at the probe can be separated from those of the disturbers during the near-field far-field transformation if the disturber locations are known. In this paper, we present ways of modeling the scattering centers on equivalent surfaces such that echo suppression is possible with only partial or no information about the geometry of the scatterers.

Determination of aerial far-field radiation patterns from near-field measurements

1971 ◽  
Vol 7 (11) ◽  
pp. 296-298 ◽  
Author(s):  
T. Birand ◽  
A. Marinçiç
Keyword(s):  
Near Field ◽  
Field Measurements ◽  
Far Field ◽  
Radiation Patterns ◽  
Field Radiation

Classical connection between near-field interactions and far-field radiation and the relevance to quantum photoemission

2013 ◽  
Vol 81 (5) ◽  
pp. 351-358 ◽  
Author(s):  
Justin Peatross ◽  
John P. Corson ◽  
Grayson Tarbox
Keyword(s):  
Near Field ◽  
Far Field ◽  
Field Radiation

Near-field scanning optical microscopy local luminescence studies of rhodamine dye

Open Physics ◽  
2010 ◽  
Vol 8 (3) ◽  
Author(s):  
Petr Klapetek ◽  
Juraj Bujdák ◽  
Jiří Buršík
Keyword(s):  
Time Domain ◽  
Near Field ◽  
Optical Microscope ◽  
Far Field ◽  
Luminescence Signal ◽  
Local Topography ◽  
Field Radiation ◽  
Scanning Optical Microscopy ◽  
Rhodamine Dye ◽  
Near Field Scanning

AbstractThis article presents results of near-field scanning optical microscope measurement of local luminescence of rhodamine 3B intercalated in montmorillonite samples. We focus on how local topography affects both the excitation and luminescence signals and resulting optical artifacts. The Finite Difference in Time Domain method (FDTD) is used to model the electromagnetic field distribution of the full tip-sample geometry including far-field radiation. Even complex problems like localized luminescence can be simulated computationally using FDTD and these simulations can be used to separate the luminescence signal from topographic artifacts.

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