Bendable and Stretchable Microfluidic Liquid Metal-Based Filter

A mechanically foldable and stretchable filter with stable filtering performance is presented in this letter. The filter is manufactured with liquid metal injected into microfluidic channels, which are realized in material of polydimethylsiloxane using soft lithography. The elastic dielectric material and liquid metal enable the deformation capability and mechanical stability of the filter along any direction. Frequency response, insertion loss, and return loss of the bended and stretched filters are investigated and compared with their original state through simulations and experiments. The fabricated filter demonstrates an insertion loss of 1.3 dB at the center frequency of 2.1 GHz and a return loss better than 10 dB over 1.6-2.6 GHz, and the overall filter size is 33 mm × 25.3 mm. Experiments verify that stretching up to 20% and bending with radii of 8.5 and 11.5 mm are possible with maintained electrical specifications.