Metasurface-Based Tapered Waveguide Slot Array Antennas for Wide Angular Scanning in a Narrow Frequency Band

We demonstrate the frequency scanning performances from a linearly tapered rectangular waveguide slot array antenna using the spatial angular filtering metasurface. To be more specific, the metasurface at the narrow side of the waveguide is shown to be capable of releasing different wavelength energies when under the illuminations from different incident angles, while the tapered waveguide is proposed to mimic the oblique incidence and thus functions as the excitation of the antenna. Such frequency scanning radiations can also be extended for both orthogonally polarized electromagnetic fields when integrated with another polarization selective surface properly behind the metasurface. Finally, we carry out the experiments to verify our proposed designs and demonstrate the excellent beam-scanning performances when the frequency is changing.