Magnetic field radiation model of ultra-low frequency mechanical antenna array based on rotating permanent magnet

Mechanical antenna refers to an emerging communication technology that drives a magnetic charge source or a charge source to perform a certain variable speed motion to generate an ultra-low frequency electromagnetic field.It It is conducive to solving the problems of huge volume, complex network impedance-matching, low radiant efficiency and high power consumption of traditional electric small antennas in this frequency band. It has a wide application prospect for communication in underwater and underground environments. In this paper,Based on the radiation theory of single rotating permanent magnet, It is proposed to form an array of multiple permanent magnets and establish a rotating permanent magnet array model by using the vector synthesis method , The correctness of the model is verified by finite element simulation. The influence of phase difference between rotating permanent magnets on the radiation pattern of near field is studied. Compared with a single rotating permanent magnet, the propagation distance increases by 23.5% under certain conditions. The correctness and feasibility of the model are verified by the measured results of the mechanical antenna array prototype.