Tailoring Group Delay Dispersion of Spatial Phaser using Anisotropic Metasurface and Polarized Incident Waves

Metasurface-based spatial phaser, exhibiting dispersive group delay responses, is able to perform real-time analogue signal processing on the temporal spectrum of spatial electromagnetic waves, e.g., Fourier transformation, pulse chirping, pulse spread, and compression. The functionality of a spatial phaser is closely related to its group delay dispersion slope. For instance, for an up-chirped incident pulse, the positive-slope-dispersion phaser spreads the pulse whereas the negative-slope-dispersion one compresses the pulse. Most reported spatial phasers exhibit fixed dispersion slopes and hence perform single functionality only, which cannot meet the demand of multifunctional systems in communication and sensing applications. In this paper, a new way is proposed to control and tune the dispersion slope of spatial phasers using polarization of incident waves, which is simpler and more efficient than conventional approaches based on tunable circuits. To verify the proposed method, a first-order spatial phaser is designed and experimentally demonstrated within 9.4-10.6 GHz. It is able to generate negative-slope, positive-slope, and zero-slope group delay dispersions, in case of x-, y-, and +/- 45 degrees-polarized waves. Such a reconfigurable phaser may find wide applications in integrated communication and sensing.