Spatial wave control using a self-biased nonlinear metasurface at microwave frequencies.

Area of Science:

• Electromagnetics and Metamaterials
• Nonlinear Optics and Wave Phenomena

Background:

• Metasurface research is expanding into nonlinear wave control for tunable applications.
• Nonlinearity offers promising avenues for achieving multiplexed metasurface performances.
• Passive nonlinear metasurfaces at microwave frequencies remain an underexplored area.

Purpose of the Study:

• To demonstrate a passive wideband nonlinear metasurface operating at microwave frequencies.
• To investigate the dual-state functionality of the proposed metasurface under varying power intensities.
• To explore the potential of this nonlinear metasurface for advanced wave manipulation applications.

Main Methods:

• Design and simulation of a passive nonlinear metasurface using L-shape and Γ-shape meta-atoms with PIN-diode elements.
• Characterization of metasurface performance as a Quarter Wave Plate (QWP) at low power intensities.
• Analysis of metasurface behavior as a digital metasurface for beam manipulation at high power intensities.
• Validation through full-wave and nonlinear simulations.

Main Results:

• The metasurface operates as a QWP from 13.24 GHz to 16.38 GHz with an Axial Ratio (AR) exceeding 21.2%.
• At high power, it functions as a digital metasurface, enabling beam synthesis (diffusion-like, chessboard patterns) across an ultra-wideband (8.12 GHz to 19.27 GHz, BW=81.4%).
• The proposed design is self-biased and exhibits polarization conversion capabilities.

Conclusions:

• A passive wideband nonlinear metasurface with dual-state functionality has been successfully manifested.
• The metasurface demonstrates significant potential for applications in limiter metasurfaces and compact reconfigurable imaging systems.
• This work opens new opportunities for nonlinear passive metasurface design in the microwave regime.