Waveform-selective Huygens Metasurfaces for Antenna Applications

Huygens metasurfaces (HMS) are usually made of unit-cells composed of a cascaded configuration of impedance sheets returning a specific phase insertion for a fixed frequency. Here, we discuss the design of self-reconfigurable HMS exhibiting two different phase-gradients depending not only on the frequency of the impinging field but also on its temporal waveform. We show that the reconfigurability of the cells can be obtained by modifying the impedance sheet of just one layer, greatly simplifying the complexity of the fabrication process. As a case study, the HMS is designed to coat a conventional dipole antenna and introduce beamforming functionalities in the presence of a signal characterized by a very short pulse width, whilst the original omnidirectional pattern of the antenna is exhibited for a continuous waveform.