Liquid Metals in Radio Frequency Applications: A Review of Physics, Manufacturing, and Emerging Technologies

Abstract

Liquid metal (LM) materials are redefining the design of soft and stretchable radio frequency (RF) devices by combining high electrical conductivity with mechanical reconfigurability. Recent advances demonstrate the use of LM in a wide range of RF components, including inductors, capacitors, antennas, and sensors, where geometry‐dependent electromagnetic properties enable new forms of wearable, bio‐integrated, and adaptive electronics. This review focuses on the underlying physics of RF loss in LM systems, including skin and proximity effects, magnetic and parasitic losses, and the influence of mechanical strain on resonant behavior. Beyond planar designs, emerging LM‐compatible fabrication methods such as freeze casting, 2.5D and 3D printing, and viscosity tuning are explored to construct conformal, high‐performance RF structures. Applications range from deformable Magnetic Resonance Imaging (MRI) coils and reconfigurable antennas to skin‐mounted wireless power transfer systems. The integration of LM with magnetic and dielectric materials to achieve multifunctional RF responses is also discussed. Finally, key opportunities in high‐frequency design, system‐level integration, and scalable soft manufacturing are outlined, positioning LM RF platforms as a versatile foundation for the next generation of communication, sensing, and biomedical technologies.