Wideband Scattering Diffusion by using Diffraction of Periodic Surfaces and Optimized Unit Cell Geometries

Area of Science:

• Electromagnetics and Metamaterials
• Surface Wave Physics
• Antenna and Microwave Engineering

Background:

• Traditional artificial surfaces often exhibit limited bandwidth and directional scattering capabilities.
• Achieving wideband, multi-directional scattering is crucial for advanced electromagnetic applications.
• Existing designs may require complex fabrication processes, limiting practical implementation.

Purpose of the Study:

• To present a novel methodology for designing periodic artificial surfaces that achieve wideband scattering diffusion.
• To enable scattering towards multiple propagation directions over an extremely wide frequency band.
• To optimize the unit cell geometry for minimized reflection and improved performance.

Main Methods:

• Utilizing unit cells with optimized geometry arranged in a periodic lattice with a repetition period larger than one wavelength.
• Employing a genetic algorithm combined with the periodic Method of Moments for optimizing the Frequency Selective Surface (FSS) geometry.
• Minimizing the reflection coefficient of the fundamental Floquet harmonic across a wide frequency band.

Main Results:

• The proposed surfaces demonstrate scattering towards multiple propagation directions over an extremely wide frequency band.
• The optimized unit cell geometry and lattice arrangement effectively induce multiple Floquet harmonics.
• The design method was validated through comprehensive full-wave simulations and experimental measurements.

Conclusions:

• The developed methodology provides a robust solution for wideband scattering diffusion using periodic artificial surfaces.
• The proposed surfaces offer superior performance in terms of bandwidth-thickness ratio.
• This approach eliminates the need for high-resolution printing processes, simplifying fabrication and enhancing practical applicability.