Digital programmable metasurfaces provide a very powerful and versatile platform for implementing spatio-temporal modulation schemes that are of great interest within the emerging framework of space–time metastructures. In particular, space–time-coding digital metasurfaces have been successfully applied to advanced wavefront-manipulations in both the spatial and spectral domains. However, conventional space–time-coding schemes do not allow the joint syntheses of the transmission/scattering angular responses at multiple frequencies, which are potentially useful in a variety of applications of practical interest. Here, a strategy is put forward to lift this limitation, thereby enabling joint multi-frequency beam shaping and steering, that is, the independent and simultaneous syntheses of prescribed scattering patterns at given harmonic frequencies. The proposed approach relies on a more sophisticated space–time coding, with suitably designed, and temporally intertwined coding sub-sequences, which effectively disentangles the joint multi-frequency syntheses. The power and versatility of the approach are illustrated via a series of representative application examples, including multi-beam, diffuse-scattering, and orbital-angular-momentum patterns. Theoretical predictions are experimentally validated by means of microwave measurements. The outcomes of this study hold promising potentials for applications to future imaging, information, and mobile-communication systems.

Joint Multi-Frequency Beam Shaping and Steering via Space–Time-Coding Digital Metasurfaces

Castaldi G.;Moccia M.;Galdi V.
2020-01-01

Abstract

Digital programmable metasurfaces provide a very powerful and versatile platform for implementing spatio-temporal modulation schemes that are of great interest within the emerging framework of space–time metastructures. In particular, space–time-coding digital metasurfaces have been successfully applied to advanced wavefront-manipulations in both the spatial and spectral domains. However, conventional space–time-coding schemes do not allow the joint syntheses of the transmission/scattering angular responses at multiple frequencies, which are potentially useful in a variety of applications of practical interest. Here, a strategy is put forward to lift this limitation, thereby enabling joint multi-frequency beam shaping and steering, that is, the independent and simultaneous syntheses of prescribed scattering patterns at given harmonic frequencies. The proposed approach relies on a more sophisticated space–time coding, with suitably designed, and temporally intertwined coding sub-sequences, which effectively disentangles the joint multi-frequency syntheses. The power and versatility of the approach are illustrated via a series of representative application examples, including multi-beam, diffuse-scattering, and orbital-angular-momentum patterns. Theoretical predictions are experimentally validated by means of microwave measurements. The outcomes of this study hold promising potentials for applications to future imaging, information, and mobile-communication systems.
2020
beam shapings
codings
digitals
joint multi-frequency syntheses
metasurfaces
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12070/45988
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 50
  • ???jsp.display-item.citation.isi??? 50
social impact