scholarly journals Near-field investigation of THz surface-wave emission from optically excited graphite flakes

2011 ◽  
Vol 19 (5) ◽  
pp. 4667 ◽  
Author(s):  
M. Nagel ◽  
A. Michalski ◽  
T. Botzem ◽  
H. Kurz
Keyword(s):  
Surface Wave ◽  
Near Field ◽  
Field Investigation ◽  
Wave Emission

Near-field investigation of Bloch surface wave based 2D optical components

2017 ◽  
Author(s):  
R. Dubey ◽  
B. Vosoughi Lahijani ◽  
M.-S. Kim ◽  
E. Barakat ◽  
M. Häyrinen ◽  
...  
Keyword(s):  
Surface Wave ◽  
Near Field ◽  
Field Investigation ◽  
Optical Components ◽  
Bloch Surface Wave

Near‐Field Investigation of a Shaded Transducer

1961 ◽  
Vol 33 (6) ◽  
pp. 836-836
Author(s):  
D. L. Baird ◽  
C. M. McKinney
Keyword(s):  
Near Field ◽  
Field Investigation

scholarly journals Broadband Generalized Sidelobe Canceler Beamforming Applied to Ultrasonic Imaging

2020 ◽  
Vol 10 (4) ◽  
pp. 1207
Author(s):  
Jiake Li ◽  
Zhe Ma ◽  
Lei Mao ◽  
Zhengjun Wang ◽  
Yi Wang ◽  
...  
Keyword(s):  
Near Field ◽  
Simulated Data ◽  
Noise Signal ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
Lateral Resolution ◽  
Wavelet Domain ◽  
Sidelobe Level ◽  
Wave Emission ◽  
Single Emission

A broadband generalized sidelobe canceler (Broadband-GSC) application for near-field beamforming is proposed. This approach is implemented in the wavelet domain. Broadband-GSC provides a set of complex, adapted apodization weights for each wavelet subband. The proposed method constrains interference and noise signal to improve the lateral resolution with only one single emission. Performance of the proposed beamforming is tested on simulated data obtained with Field II. Experiments have proved that the new beamforming can significantly increase the image quality compared with delay-and-sum (DAS) and synthetic aperture (SA). Imaging of scattering points show that Broadband-GSC improves the lateral resolution by 43.2% and 58.0% compared with SA and DAS, respectively. Meanwhile，Broadband-GSC reduces the peak sidelobe level by 11.6 dB and 26.4 dB compared with SA and DAS, respectively. Plane wave emission experiment indicates that Broadband-GSC can improve the lateral resolution by 44.2% compared with DAS. Furthermore, the new beamforming introduces the possibility for higher frame-rate and higher investigation depth with increased lateral resolution.

Near-field investigation of turbulence produced by multi-scale grids

2012 ◽  
Vol 24 (3) ◽  
pp. 035103 ◽  
Author(s):  
P.-Å. Krogstad ◽  
P. A. Davidson
Keyword(s):  
Near Field ◽  
Field Investigation ◽  
Multi Scale

Surface-Wave Green's Tensors in the Near Field

2014 ◽  
Vol 104 (3) ◽  
pp. 1578-1586 ◽  
Author(s):  
M. M. Haney ◽  
H. Nakahara
Keyword(s):  
Surface Wave ◽  
Near Field
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