Spatial Wave Control Using a Self-biased Nonlinear Metasurface at Microwave Frequencies

TL;DR

This paper presents a passive, self-biased nonlinear metasurface at microwave frequencies that switches between wave control states based on power levels, enabling wideband polarization manipulation and beam shaping.

Contribution

It introduces a novel passive nonlinear metasurface with embedded PIN-diodes capable of wideband operation and dual functionality at different power levels.

Findings

Acts as a Quarter Wave Plate at low power from 13.24 to 16.38 GHz.

Functions as a digital metasurface for beam manipulation from 8.12 to 19.27 GHz.

Demonstrates wideband nonlinear performance through simulations.

Abstract

Recently, the investigation of metasurface has been extended to wave control through exploiting nonlinearity. Among all of the ways to achieve tunable metasurfaces with multiplexed performances, nonlinearity is one of the promising choices. Although several proposals have been reported to obtain nonlinear architectures at visible frequencies, the area of incorporating nonlinearity in form of passive-designing at microwave metasurfaces is open for investigation. In this paper, a passive wideband nonlinear metasurface is manifested, which is composed of embedded L-shape and {\Gamma}-shape meta-atoms with PIN-diode elements. The proposed self-biased nonlinear metasurface has two operational states: at low power intensities, it acts as Quarter Wave Plate (QWP) in the frequency range from 13.24 GHz to 16.38 GHz with an Axial Ratio (AR) of over 21.2%. In contrast, at high power intensities, by using the polarization conversion property of the proposed PIN-diode based meta-atoms, the metasurface can act as a digital metasurface. It means that by arranging the meta-atoms with a certain coding pattern, the metasurface can manipulate the scattered beams and synthesize well-known patterns such as Diffusion-like pattern at an ultra-wide frequency range from 8.12 GHz to 19.27 GHz (BW=81.4%). Full-wave and nonlinear simulations are carried out to justify the performance of the wideband nonlinear metasurface. We expect the proposed self-biased nonlinear metasurface at microwave frequencies reveals excellent opportunities to design limiter metasurfaces and compact reconfigurable imaging systems.