1993 Fiscal Year Final Research Report Summary
Study of Equivalent Edge Currents in Geometrical
| Project/Area Number |
04452182
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理学一般
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
ANDO Makoto Tokyo Institute of Technology Fae, of Eng., 工学部, 助教授 (90159533)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Method of equivalent edge currents (MEC) / Fiotitious penetrating rays / Modified edge representation (MER) / High frequency technique / Diffraction / Physical optics (PO) / Frings wave (FW) |
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| Research Abstract |
The method of equivalent edge ourrents (MEC) extends the applicability of geometrical theory of diffraction (GTD) with the minimum complexity. Fields are expressed in terms of line integration of fictitious line currents called equivalent edge currents (EECg). The accuracy of MEC is greatly dependent upon the quality of expressions of EECs. This work gives two novel concepts and methods for defining EECs for general edge points. "EECs using paths of most rapid phase variation" succeeds in eliminating all the false singularities. "Modified edge representation (MER)" based upon generalized Fermat's principle are proposed and succeeds in defining accurate EECs with only the classical Keller's diffraction coefficients. Following results are obtained.
The validity of MER is numerically checked. It has almost the same potential as the UTD, which is known for the highest accuracy
MER, as applied to the PO components, gives numerically perfect accuracy in reducing the surface to line integral reduction. MER, as applied to the fringe wave components, causes erroneous results. Simple correction method is proposed, which dispense with special functions such as Fresnel integrals
Extraction of lower order diffracted waves by adopting the time gating technique was not successful due to residual reflection in unechoic chamber
Fictitious penetrating rays in PO is found for the first time. This ray exist in the surface with the curvature
Visualization of diffracted fields in terms of EECs has started and fictitious penetrating rays are demonstrated
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