Miniaturised wideband metasurface polarisation converter with high angular stability

Area of Science:

• Electromagnetics and Metamaterials
• Microwave Engineering
• Antenna and RF Technology

Background:

• Metasurfaces offer unique electromagnetic properties for wave manipulation.
• Efficient linear-to-circular polarization conversion is crucial for various wireless communication systems.
• Miniaturized and wideband solutions are highly sought after in modern RF designs.

Purpose of the Study:

• To design and demonstrate a single-layer, miniaturized, wideband transmissive linear-to-circular polarization converter.
• To investigate the impact of meandered metallic strips and engineered gaps on converter performance.
• To validate the wide-angle stability and high transmission efficiency of the proposed metasurface.

Main Methods:

• Utilizing symmetrically arranged meandered metallic strips with engineered gaps in a unit cell design.
• Employing numerical simulations and experimental measurements for validation.
• Characterizing the metasurface's performance in terms of fractional bandwidth, axial ratio, angular stability, and insertion loss.

Main Results:

• Achieved wideband linear-to-circular polarization conversion from 5.23 to 12.85 GHz (84.3% fractional bandwidth).
• Obtained an axial ratio below 3 dB across the operating band.
• Demonstrated high angular stability up to 85° (TE mode) and 60° (TM mode) with low insertion loss (1.6–2.69 dB).
• The metasurface exhibits an ultra-thin profile (0.0038 λ_o) and compact dimensions.

Conclusions:

• The proposed single-layer metasurface effectively realizes wideband and wide-angle stable linear-to-circular polarization conversion.
• The meandered geometry is key to achieving miniaturization and enhanced performance.
• The validated design holds promise for advanced RF and microwave applications requiring efficient polarization control.