Optimisation of phase factor in phase retrieval for reflector antennas with active surface

2018 ◽  
Vol 12 (15) ◽  
pp. 2285-2291
Author(s):  
Yueshu Xu ◽  
Qian Ye ◽  
Guoxiang Meng
Keyword(s):  
Phase Retrieval ◽  
Active Surface ◽  
Phase Factor ◽  
Reflector Antennas

Surface error measurements of large reflector antennas by phase retrieval holography—an application of extrapolation algorithm

1996 ◽  
Vol 79 (4) ◽  
pp. 104-114 ◽  
Author(s):  
Toshiyuki Nishibori ◽  
Hisashi Hirabayashi ◽  
Hideyuki Kobayashi ◽  
Yasuhiro Murata ◽  
Yutaka Shimawaki ◽  
...  
Keyword(s):  
Phase Retrieval ◽  
Reflector Antennas ◽  
Surface Error ◽  
Extrapolation Algorithm

An active surface for large reflector antennas

2004 ◽  
Vol 46 (4) ◽  
pp. 11-19 ◽  
Author(s):  
A. Orfei ◽  
M. Morsiani ◽  
G. Zacchiroll ◽  
G. Maccaferri ◽  
J. Roda ◽  
...  
Keyword(s):  
Active Surface ◽  
Reflector Antennas

Quantitative analysis by reconstruction of HREM focal series

1994 ◽  
Vol 52 ◽  
pp. 740-741
Author(s):  
W. Coene ◽  
A. Thust ◽  
M. Op de Beeck ◽  
D. Van Dyck
Keyword(s):  
Phase Retrieval ◽  
Image Plane ◽  
Initial Guess ◽  
Recursive Least Squares ◽  
Objective Lens ◽  
Electron Wave ◽  
Electron Sources ◽  
Original Algorithm ◽  
Coherent Field ◽  
Direct Interpretation

Compared to conventional electron sources, the use of a highly coherent field-emission gun (FEG) in TEM improves the information resolution considerably. A direct interpretation of this extra information, however, is hampered since amplitude and phase of the electron wave are scrambled in a complicated way upon transfer from the specimen exit plane through the objective lens towards the image plane. In order to make the additional high-resolution information interpretable, a phase retrieval procedure is applied, which yields the aberration-corrected electron wave from a focal series of HRTEM images (Coene et al, 1992).Kirkland (1984) tackled non-linear image reconstruction using a recursive least-squares formalism in which the electron wave is modified stepwise towards the solution which optimally matches the contrast features in the experimental through-focus series. The original algorithm suffers from two major drawbacks : first, the result depends strongly on the quality of the initial guess of the first step, second, the processing time is impractically high.

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