  Wireless communications and sensing have notably advanced thanks to the
recent developments in both software and hardware. Although various modulation
schemes have been proposed to efficiently use the limited frequency resources
by exploiting several degrees of freedom, antenna performance is essentially
governed by frequency only. Here, we present a new antenna design concept based
on metasurfaces to manipulate antenna performances in response to the time
width of electromagnetic pulses. We numerically and experimentally show that by
using a proper set of spatially arranged metasurfaces loaded with lumped
circuits, ordinary omnidirectional antennas can be reconfigured by the incident
pulse width to exhibit directional characteristics varying over hundreds of
milliseconds or billions of cycles, far beyond conventional performance. We
demonstrate that the proposed concept can be applied for sensing, selective
reception under simultaneous incidence and mutual communications as the first
step to expand existing frequency resources based on pulse width.
