Liquid metal-based electromagnetic metasurface for continuous RCS reduction adjustment.

A liquid metal microfluidic metasurface is demonstrated for the continuous and simultaneous reconfiguration of electromagnetic properties, including phase, resonance frequency, and reflection amplitude. The metasurface, constructed from each split-ring cell with a variable cross-section, is fabricated using a polydimethylsiloxane array microchannel molding process. The designed subarray (5 × 3 units) of the metasurface enables continuous, independent, and differential regulation by bistable liquid metal microfluidics. A continuous state coding method for electromagnetic reconfiguration is proposed and validated through both simulations and experimental tests. The resonant frequency and reflection amplitude are experimentally tested by a 30 cm × 30 cm liquid metal metasurface, demonstrating a frequency reconfiguration range from 2.1 to 5.1 GHz and a continuous reflection amplitude regulation of up to 10 dB within the 2.5 to 6.5 GHz range. The relative bandwidth and absolute bandwidth are up to 88.89% and 4 GHz, respectively. Therefore, this technique provides an effective approach for broadband continuous reconfiguration and multi-bit coding of electromagnetic responses with low-power consumption.