Enabling Reconfigurable All-Liquid Microcircuits via Laplace Barriers to Control Liquid Metal

Liquid metals such as gallium alloys have a unique potential to enable fully reconfigurable RF electronics. One of the major concerns for liquid-metal electronics is their interaction with solid-metal contacts, which results in unwanted changes to electrical performance and delamination of solid- metal contacts due to atomic diffusion of gallium at the liquid/solid interface. In this paper, we present a solution to this problem through way of liquid-metal/liquid-metal RF connections by implementing Laplace barriers, which control fluid flow and position via pressure-sensitive thresholds to facilitate physical movement of the fluids within the channels. We demonstrate RF switching within the channel systems by fabricating, testing, and modeling a reconfigurable RF microstrip transmission line with integrated Laplace barriers which operates between 0.5-5 GHz. This approach opens the potential for future all-liquid reconfigurable RF electronic circuits where physical connections between solid and liquid metals are minimized or possibly eliminated altogether.