Self-biased tri-state power-multiplexed digital metasurface operating at microwave frequencies

Exploiting of nonlinearity has opened doors into undiscovered areas to achieve multiplexed performances in recent years. Although efforts have been made to obtain diverse nonlinear architectures at visible frequencies, the room is still free for incorporating non-linearity into the design of microwave metasurfaces. In this paper, a passive dual-band power intensity-dependent metasurface is presented, which is composed of two different linear and nonlinear meta-atoms accommodating a capacitor and a PIN-diode, respectively. The proposed digital metasurface has three operational states: 1) it acts as a normal reflector at low power intensities while providing a dual-band nonlinear response upon illuminating by high-power incidences where 2) it perfectly absorbs the radiations at f₁=6.7 GHz and 3) re-distributes the scattered beams by arranging the meta-atoms with a certain coding pattern at f₂=9.4 GHz. The performance of the designed coding elements has been characterized by using the scattering parameters captured in the full-wave simulations and the nonlinear analysis performed in ADS software where the accurate model of diodes is involved. The emergence of microwave self-biased metasurfaces with smart re-actions against incident waves with different power levels reveals great opportunities for designing smart windows, smart camouflage coating surfaces, and so on.