Piezoelectrically actuated magnetic dipole twisting resonators enable miniaturized low-frequency antennas

Miniaturized low-frequency antennas are essential for underwater, underground, and biomedical communications, yet their performance is constrained by the fundamental size-efficiency trade-off, a long-standing physical bottleneck. Here, we introduce a radiation mechanism that circumvents this constraint by replacing the time-varying currents in conventional antennas with the mechanical twisting oscillation of a magnetic dipole. Using piezoelectrically actuated, biomimetic twisting resonators with ultrahigh mechanical quality factors, we demonstrate that low-frequency antennas operating at 15.4 and 668 hertz can be miniaturized to centimeter- and millimeter-scale, respectively, with radiation efficiencies exceeding those of size-matched loop antennas by factors of 49,000 and 5000, respectively. This electromechanical-magnetic transduction enables underwater cross-medium communication over 115 meters with only milliwatt-level power consumption, using 99.9% less power than loop antennas. It also supports implantable wireless devices that achieve a fourfold increase in communication range at identical power consumption, opening a route to long-range, low-power wireless systems capable of operating in some of the most demanding environments.