Fig. 2

The programmable metamaterials. a The fabricated sample of programmable metamaterials. (from Fig. S6 of Ref. [56]). b The designed programmable element. (from Fig. S4 of Ref. [56]). c The designed structure of programmable element. (from Fig. 6 of Ref. [56]). d The simulated phase responses of the programmable element. (from Fig. 6 of Ref. [56]). e The operation process of the programmable metamaterials. (from Fig. 7 of Ref. [56]). Reproduced with permission from Ref. [56] under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Copyright 2014, Springer Nature