On the Validity of Physical Optics for Narrow-band Beam Scattering and Diffraction from the Open Cylindrical Surface

TL;DR

This paper derives exact formulas for surface currents on open cylindrical surfaces caused by narrow-band beams, assessing the accuracy of the Physical Optics approximation through analytical and numerical methods.

Contribution

It provides closed-form expressions for surface currents using cylindrical harmonics, enabling evaluation of the Physical Optics approximation's validity.

Findings

Exact formulas for surface currents derived

Numerical example with Hermite Gaussian beam included

Assessment of PO approximation validity for cylindrical surfaces

Abstract

The exact formulas for the induced electric surface current (in the scattering phenomenon) and the equivalent electric surface current (in the diffraction phenomenon) on the open cylindrical surface due to an arbitrary narrow-band beam have been shown in their closed-form expressions within the context of the cylindrical harmonics, which gives information about the validity of the Physical Optics (PO) approximation. Both the Electric Field Integral Equation (EFIE) and the Magnetic Field Integral Equation (MFIE) are used to find the induced (equivalent) electric surface currents in the context of the cylindrical harmonics. The numerical example of the scattering and diffraction of the Hermite Gaussian beam from the open cylindrical surface is shown. The result is useful for the evaluation of the validity of the PO approximation in the cylinder-like surface.