High-frequency diffraction by an elliptic cylinder: the near field

Abstract

The problem of diffraction by a perfectly conducting cylinder with the cross section being an ellipse with high aspect ratio is examined. The high-frequency asymptotics of the currents induced by a plane electromagnetic wave incident along or at a small angle to the major axis of the ellipse is constructed. The field in the boundary layer near the surface is represented as a sum of the forward and the backward waves, both considered in parabolic equation approximation. Comparison with numerical test shows that the leading order term of the asymptotics provides sufficiently accurate approximation for the induced currents on cylinders of one wavelength size and larger.

Keywords:

• diffraction
• elliptic cylinder
• high frequency
• strong elongation