Stretchable antennas are increasingly important for wearable electronics, soft robotics, and conformal wireless systems that require mechanically compliant radiofrequency components capable of operating under deformation. Among various approaches, liquid metal-based antennas offer a promising combination of high conductivity and mechanical compliance. However, most existing liquid metal antennas rely on embedded microfluidic channels and cleanroom-based fabrication, which limit scalability, design flexibility, and rapid prototyping. Here, we introduce a cleanroom-free, stencil-based fabrication strategy that combines 3D printing, replica molding, and templated blade coating of oxidized eutectic gallium–indium to produce stretchable patch antennas on soft silicone substrates. By integrating multilevel fractal-inspired slot geometries, the antennas achieve lower operating frequencies within the same footprint and tunable, direction-sensitive frequency shifts under uniaxial, transverse, and biaxial stretching of up to 40%. Full-wave finite-element simulations confirm the frequency-tuning behavior. When mounted on the human elbow, the antenna conforms to joint motion and enables direction-sensitive wireless strain sensing. This platform provides a scalable, miniaturized, and mechanically robust route to stretchable liquid metal patch antennas for wearable sensing applications.
Chen et al. (Tue,) studied this question.