A reconfigurable Yagi-Uda antenna using EGaIn liquid metal

A reconfigurable Yagi-Uda with the liquid metal is proposed in this article. By a new electrochemical method for reversible, we control the length of liquid eutectic gallium indium (EGaIn) in the capillary. Electrochemical deposition (or explode) of a surface-oxide on the EGaIn significantly lowers (or increases) its tension to induce the liquid metal up (or down) of the capillary. The three-element array consists of the elements whose lengths can be changed with the liquid metal, resulting in the array directors can be transformed into reflectors, and elements can be changed to the different frequencies. Simulation in CST shows that good impedance matching is realized from 0.85 to 0.95 GHz with the gain over 5dBi and the VSWR lower than 2 across the entire band. The utilization coefficient of aperture field reached 70%. This antenna can be widely used in millimeter radar or communication system.