Space-Time Modulated Metasurface Antennas for Near-Field Focusing Applications

This paper introduces the design of a novel near-field focused metasurface antenna utilizing space-time modulation technology. The antenna is capable of concentrating the radiated electromagnetic wave into a specific focal spot in the near-field region, making it ideal for use in a range of applications, such as sensing, imaging, and wireless power transfer. The holographic approach is utilized to synthesize the required amplitude envelope along the wave-guiding structure. Additionally, the space-time modulated (STM) metasurface antenna can cyclically on-off switch its meta-atoms to form an equivalent synthetic envelope along the length of the metasurface antenna aperture. The proposed STM metasurface antenna is validated through measurement results, which demonstrate its near-field focused capability.