Liquid‐metal frequency‐reconfigurable slot antenna using air‐bubble actuation

Abstract

Liquid metal actuated by pressure‐driven air bubbles is guided within channels to dynamically reconfigure the length of the radiating aperture and feed line of a slot antenna. The gallium‐based liquid metal is held in position by air bubbles, and liquid‐metal motion is induced when a pressure differential is created. In contrast to conventional hydraulic or pneumatic actuation of gallium‐based liquid metal, the pressure actuation described here is reversible and repeatable, as the liquid metal is enveloped by a thin layer of NaOH solution, which acts as a slip layer and reduces any metal oxidation. The slot antenna achieves a 26% tunable bandwidth with a contiguous range from 1.42 to 1.84 GHz for which the S 11 is <−10 dB. The peak gain ranges from 4.8 dBi in its lowest‐frequency state to 4.1 dBi in its highest‐frequency state.