Low-RCS Antenna Array With Switchable Scattering Patterns Employing Microfluidic Liquid Metal Alloy-Based Metasurface

In this communication, the liquid metal alloy (LMA) is utilized to design a metasurface with switchable reflection phases, which serves as the superstrate of an antenna array to manipulate its scattering features. The proposed metasurface is composed of a silicone rubber etched with microfluidic channels. Hence, its electromagnetic properties can be controlled by the filling of LMA. Simulated results reveal that the injection of LMA shifts the phase of waves reflected from the proposed metasurface by 180° ranging from 8 to 32 GHz. Then, the proposed metasurface covers a slot antenna array to regulate its scattering characteristic. By arranging the filling of LMA with various configurations, the scattering pattern can be switched among four different states with a slight influence on its radiation performance. Fulfilling all microfluidic channels with air, the reference antenna has a normal scattering pattern like a metallic plate. Moreover, by switching the filling area of LMA, monostatic radar cross-section (RCS) reduction is realized in three of these four working states. Finally, we had processed and tested a demonstrated prototype of the slot antenna array along with the proposed metasurface superstrate. Measured results are consistent well with the simulation. An implication of this research is the possibility that manipulating the scattering features of an antenna array without influences on its radiation characteristics by employing LMA.