Compact super-low frequency mechanical transmitting antenna based on high-temperature superconducting magnets

Mechanical antennas provide a feasible approach to generating super-low frequency (SLF) electromagnetic waves, however, their limited radiation intensity and frequency modulation remain bottlenecks constraining practical applications. In this paper, a SLF mechanical transmitting antenna based on high-temperature superconducting magnet is proposed. Unlike conventional mechanical antennas that rely on rotating permanent magnets with the limited magnetic field, the proposed design employs a fixed superconducting coil to provide a static background field, which is modulated by the motion of rotor to generate the time-varying magnetic field. A prototype was fabricated and tested. Experimental results demonstrate that the proposed antenna can effectively emit SLF magnetic signals, whose amplitude increases linearly with the operating current of the superconducting magnet. Moreover, the signal frequency can be flexibly modulated by adjusting the motor speed and rotor configuration. The operating principles and radiation characteristics of the antenna have also been analyzed. These designs and analyses verify the feasibility of mechanical antenna based on superconducting magnet for SLF signal transmission, and paves the way for advancing the performance of compact mechanical antenna systems.