Using Near Field Equivalent Sources in Combination with Large Element Physical Optics to Model a Slant 45 Degree Omni Directional Antenna over Ground

2021 ◽  
Vol 35 (11) ◽  
pp. 1362-1363
Author(s):  
Keith Snyder
Keyword(s):  
Near Field ◽  
Ground Plane ◽  
Directional Antenna ◽  
Physical Optics ◽  
Large Element ◽  
Far Fields ◽  
Equivalent Sources

This paper compares the theoretical and measured antenna patterns of a slant 45-degree antenna on a rolled edge ground plane. Advantages of using sampled nearfield currents in combination with large element physical optics in determining the reflected far fields will be described.

Hydrodynamic Noise and Radiated Mechanism of 3D Cavity

2012 ◽  
Vol 217-219 ◽  
pp. 2590-2593 ◽  
Author(s):  
Yu Wang ◽  
Bai Zhou Li
Keyword(s):  
Sound Pressure ◽  
Near Field ◽  
Low Frequency ◽  
Dipole Source ◽  
Fluctuating Pressure ◽  
Common Structure ◽  
Hydrodynamic Noise ◽  
Near Field Sound ◽  
Equivalent Sources ◽  
Field Sound

The flow past 3D rigid cavity is a common structure on the surface of the underwater vehicle. The hydrodynamic noise generated by the structure has attracted considerable attention in recent years. Based on LES-Lighthill equivalent sources method, a 3D cavity is analyzed in this paper, when the Mach number is 0.0048. The hydrodynamic noise and the radiated mechanism of 3D cavity are investigated from the correlation between fluctuating pressure and frequency, the near-field sound pressure intensity, and the propagation directivity. It is found that the hydrodynamic noise is supported by the low frequency range, and fluctuating pressure of the trailing-edge is the largest, which is the main dipole source.

A physical optics based near-field analysis method for the design of dual polarized fan beam shaped reflector antennas

2016 ◽  
Vol 70 (2) ◽  
pp. 132-137 ◽  
Author(s):  
E. Bagheri-Korani ◽  
K. Mohammadpour-Aghdam ◽  
M. Ahmadi-Boroujeni ◽  
E. Arbabi ◽  
M. Nemati
Keyword(s):  
Near Field ◽  
Field Analysis ◽  
Physical Optics ◽  
Analysis Method ◽  
Reflector Antennas ◽  
Dual Polarized

Modified physical optics algorithm for near field scattering

2018 ◽  
Vol 27 (11) ◽  
pp. 114102 ◽  
Author(s):  
Bin Chen ◽  
Chuangming Tong
Keyword(s):  
Near Field ◽  
Physical Optics

scholarly journals Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations

2009 ◽  
Vol 7 ◽  
pp. 17-22 ◽  
Author(s):  
C. H. Schmidt ◽  
T. F. Eibert
Keyword(s):  
Near Field ◽  
Measurement Techniques ◽  
Plane Waves ◽  
Low Complexity ◽  
Far Field ◽  
Computation Complexity ◽  
Low Frequencies ◽  
Field Transformation ◽  
Translation Operators ◽  
Equivalent Sources

Abstract. The radiation of large antennas and those operating at low frequencies can be determined efficiently by near-field measurement techniques and a subsequent near-field far-field transformation. Various approaches and algorithms have been researched but for electrically large antennas and irregular measurement contours advanced algorithms with low computation complexity are required. In this paper an algorithm employing plane waves as equivalent sources and utilising efficient diagonal translation operators is presented. The efficiency is further enhanced using simple far-field translations in combination with the expensive near-field translations. In this way a low complexity near-field transformation is achieved, which works for arbitrary sample point distributions and incorporates a full probe correction without increasing the complexity.

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