Fast method to compute scattering by a buried object under a randomly rough surface: PILE combined with FB-SA

Area of Science:

• Electromagnetics
• Computational Physics
• Optics

Background:

• The propagation-inside-layer expansion (PILE) method efficiently calculates scattering from layered media with rough interfaces.
• Existing methods require significant computational resources for complex scattering problems.

Purpose of the Study:

• To adapt the PILE method for calculating scattering from an object situated below a single randomly rough surface.
• To enhance computational efficiency by integrating the forward-backward spectral acceleration (FB-SA) approach.

Main Methods:

• The study applies the PILE method, involving block inversion of impedance matrices, to a single rough interface scenario.
• The forward-backward spectral acceleration (FB-SA) technique is incorporated to handle large matrix inversions efficiently.
• The combined PILE-FB-SA method is validated using perfectly conducting cylinders below a dielectric rough surface with Gaussian and exponential autocorrelation functions.

Main Results:

• The developed PILE-FB-SA method provides a fast and exact numerical solution for scattering problems.
• The method accurately computes multiple-scattering contributions within the dielectric layer.
• Successful validation was achieved for scattering from circular and elliptic cylinders.

Conclusions:

• The PILE-FB-SA method offers an efficient and accurate approach for analyzing electromagnetic scattering from objects below rough surfaces.
• This advancement has implications for various applications in optics and electromagnetics involving complex interfaces.