On study of antenna-radome system near-field measurements with a spherical scanner

2020 ◽  
Vol 49 (9) ◽  
pp. 14-21
Author(s):  
A. V. Kirpanev ◽  
N. A. Kirpanev ◽  
V. V. Shubnikov
Keyword(s):  
Plane Wave ◽  
Transmission Coefficient ◽  
Near Field ◽  
Wave Spectrum ◽  
Spherical Wave ◽  
Field Measurements ◽  
Radiation Fields ◽  
Vector Characteristic ◽  
Measurement Surface ◽  
The Relationship

The paper presents a research technique for studying an antenna-radome system based on nearfield measurements with a most common «roll over azimuth» spherical scanner. It is based on the relationship between the components of the plane wave spectrum and the spherical wave coefficients, in terms of which the radiation fields of the tested antenna and the antenna-radome system are represented. Expressions for the plane wave spectrum components at the pole of the spherical measurement surface are given. To assess the effect of the radome on the antenna characteristics, it is proposed to use the spectral vector characteristic of the radome passage. Methods for estimating the dielectric constant of the radome by determining the transmission coefficient of its wall at various points on the surface are proposed. It is shown that the use of a weakly directional antenna in the study of the radome characteristics simplifies the task, since the transmission coefficient is determined using the components of the electric field strengths in spherical coordinates.

Plane wave spectrum theory applied to near-field measurements for electromagnetic compatibility investigations

2009 ◽  
Vol 3 (1) ◽  
pp. 72-83 ◽  
Author(s):  
D. Baudry ◽  
B. Mazari ◽  
Z. Riah ◽  
M. Kadi ◽  
C. Arcambal ◽  
...  
Keyword(s):  
Plane Wave ◽  
Electromagnetic Compatibility ◽  
Near Field ◽  
Wave Spectrum ◽  
Field Measurements

A comparison of near-field beamforming and acoustical holography for sound source visualization

2009 ◽  
Vol 223 (4) ◽  
pp. 819-834 ◽  
Author(s):  
Yong Thung Cho ◽  
M J Roan ◽  
J S Bolton
Keyword(s):  
Near Field ◽  
Random Noise ◽  
Sound Intensity ◽  
Field Measurements ◽  
Absolute Intensity ◽  
Visualization Technique ◽  
High Frequencies ◽  
Measurement Surface ◽  
Acoustical Holography ◽  
Source Geometry

Acoustical holography procedures make high-resolution visualization possible via estimation of the sound intensity on surfaces closer to the sources than the near-field measurement surface. Another source localization technique, beamforming, has been used to estimate the direction of arrival of sound from sources that typically lie in the far-field. However, little work has been done using beamforming as a visualization technique based on near-field measurements. As a result, the performance of beamforming and acoustical holography in terms of source resolution capabilities has not been directly compared when using near-field measurements. In this work, point source beamforming was used to visualize sources based on near-field measurements. Acoustic intensity estimated from beamformed pressure measurements was compared with the absolute intensity estimated using acoustical holography techniques. In addition to noise-free, anechoic simulations, cases of measurement pressure with random noise were generated and used to compare source resolution accuracy of acoustical holography and beamforming techniques in the presence of measurement noise. It was found that intensity estimated using acoustical holography provided the clearest image of sources when the measurement surface was conformal with the source geometry. However, sources can be resolved more accurately using near-field beamforming than acoustical holography at high frequencies when the sources are not located perfectly on a surface conformal with the measurement geometry.

Near-field analysis by the plane-wave spectrum approach

1973 ◽  
Vol 21 (2) ◽  
pp. 231-234 ◽  
Author(s):  
R. Rudduck ◽  
D.C. Wu ◽  
M. Intihar
Keyword(s):  
Plane Wave ◽  
Near Field ◽  
Wave Spectrum ◽  
Field Analysis
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