Frequency Scanning Radiation by Decoupling Spoof Surface Plasmon Polaritons via Phase Gradient Metasurface

On the basis of generalized Snell's law of reflection, we propose to achieve frequency scanning radiation by decoupling spoof surface plasmon polaritons (SSPPs) from a corrugated metallic strip (CMS). Phase gradient metasurface (PGM) is utilized to modulate the dispersion behavior of the CMS. Since the phase gradient of the PGM is contrary to the wave vector of SSPPs, the dispersion curve of SSPPs can be translated into the fast wave zone, leading to frequency scanning radiation. As an example, we demonstrate a frequency scanning antenna operating at 8.8-10.7 GHz. A prototype was designed, fabricated, and measured. The measured results show that the prototype can realize continuous beam scanning from 4.8° to 37.2°, with realized gain varying from 8 to 13.1 dB. Owing to surface confinement of SSPPs, the proposed method can be readily extended to the design of conformal frequency scanning antennas on curved faces.