volume | PIER Journals

2009-02-05

Analysis of Shadowing Processing Technique Based on Modeling Using NURBS

Yun-Xue Xu,

Dr. Yun-Xue Xu

National Key Laboratory of Antennas and Microwave Technology

Xidian University

China

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Ying Guan,

Dr. Ying Guan

National Laboratory of Antennas and Microwave Technology

Xidian University

China

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Feng-Tao Zha,

Dr. Feng-Tao Zha

Xidian University

China

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Wen Jiang,

Prof. Wen Jiang

Xidian University

China

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Shu-Xi Gong

Prof. Shu-Xi Gong

Xidian University

China

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Progress In Electromagnetics Research, Vol. 89, 325-338, 2009

doi:10.2528/PIER08123002

Abstract

The shadowing relationship between facet elements can be determined rapidly through analytical expressions. On the basis of modeling using curved surfaces, an effective shadowing processing algorithm is proposed which is in combination with that used in the shadowing judgement of facet elements. Firstly several sampling points are taken on the ergodic curved surface element to construct a group of facet elements, which can replace the curved surface element. Then the shadowing processing between the stationary phase point and the ergodic curved surface element is converted to that between the stationary phase point and several facet elements, thus avoiding utilizing optimization method and can increase the computation speed. Similarly, the shadowing processing between the stationary phase segment and the ergodic curved surface element is converted to that between the stationary phase segment and several facet elements. And the trimming algorithm is used to accurately find the visible part of the stationary phase segment, which gets rid of the rough shadowing processing technique that determines the visibility of the whole stationary phase segment through the visibility of the center of the stationary phase segment. Therefore, the computation precision is greatly improved. When there exists a huge number of curved surfaces, maximum-minimum preprocessing is utilized to increase the computation speed. Examples show that this novel algorithm is superior to the traditional one in both computation speed and precision.

Citation

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Yun-Xue Xu, Ying Guan, Feng-Tao Zha, Wen Jiang, and Shu-Xi Gong, "Analysis of Shadowing Processing Technique Based on Modeling Using NURBS," Progress In Electromagnetics Research, Vol. 89, 325-338, 2009.
doi:10.2528/PIER08123002

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