**Authors:** I. V. Andronov and R. Mittra

**Source:** FERMAT, Volume 2, Article 3, Mar.-Apr., 2014

**Abstract:** The problem of high-frequency diffraction by
elongated bodies is discussed in this work. The classical
approach is shown to require too high frequencies for its
applicability. Attempts to improve the approximating properties
of the asymptotic methods are discussed, focusing on the case of
strongly elongated bodies examined in detail. The asymptotics
are governed by the elongation parameter, the ratio of the
longitudinal wave dimensions of the body to its cross-section.
The cases of axial incidence as that of incidence at a grazing
angle to the axis are considered. Both the asymptotics of the
induced currents on the surface and of the far field amplitude
are developed. Comparison with numerical results for a set
of test problems shows that the leading terms of the new
asymptotics provide good approximation in a uniform manner
with respect to the rate of elongation.

**Index Terms:** High-frequency asymptotics, diffraction, elongated bodies.

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