  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.
