Redrawable and physically reconfigurable liquid metal microstrip patch antenna on a paper substrate

Reconfigurable antennas capable of post-fabrication modification are highly desirable for adaptive RF systems. In this work, we demonstrate a redrawable and physically reconfigurable liquid-metal microstrip patch antenna on a paper substrate. Gallium-based liquid metal was patterned onto laser-printed paper using a simple hand-drawing process. Because the liquid metal can be removed using ethanol, the antenna geometry was selectively modified through erasing and redrawing. Removal of the inner annular region shifted the resonant frequency from 3.97 GHz to 3.78 GHz, while formation of a circular patch shifted it to 4.28 GHz. Redrawing restored the original resonant characteristics. Physical reconfigurability was further demonstrated by cutting and reconnecting the antenna structure, where the resonant frequency shifted to 2.56 GHz after cutting and recovered to 3.93 GHz after reconnection. The proposed approach provides a simple and low-cost strategy for flexible and reconfigurable RF devices.