Liquid-Metal-Enabled Flexible Metasurface with Self-Healing Characteristics

A flexible self-healing metasurface using gallium-based liquid metal encapsulated in polydimethylsiloxane (PDMS) operating in the X-band (8–12 GHz) is reported. A band-stop metasurface with center frequency at 9.82 GHz is designed using floating patches surrounding the respective end cap of a Jerusalem cross. A large-scale (up to 10 × 10 array) metasurface is patterned in PDMS and a rapid manufacturing method of vacuum filling using ultra-low pressure is used to yield parallel encapsulation of liquid metal in PDMS. The fabricated metasurface is physically flexible and its flexibility is repeatedly tested for bendability, stretchability (up to ≈89.13%), twistability, and foldability. Transmission characteristics of the flexible metasurface are measured in waveguide and free-space environments and it is found that the band-stop center frequency agrees well with the design. The flexible metasurface also is tested for its repairability and self-healing characteristics. The metasurface is partially or fully cut at certain part and the partial/full cut part of the metasurface is repaired by applying external pressure or using Kapton tape/UV glue. Those repaired metasurfaces show restoration of original transmission characteristics with minimal shift in frequency and magnitude.