Radiation Principle and Spatial Direct Modulation Method of a Low Frequency Antenna Based on Rotating Permanent Magnet

The theory of mechanical antenna is still in its infancy at present, and its radiation mechanism, field distribution, modulation methods and other basic theories need to be explored and improved. The radiation mechanism of a rotating-magnet based mechanical antenna (RMBMA) is explored. An equivalent radiation model of the mechanical antenna is established. The field formula of mechanical antenna is derived using this model and rotation matrix. The spatial direct modulation method of mechanical antenna is also investigated. Two prototype antennas are fabricated using DC/AC servo motors and NdFeB magnets, and experiments are carried out to verify the correctness of the derivation and analysis. The measured and simulated results are in consistent with each other. By precisely controlling the moving parameters of an AC servo motor, signal of binary amplitude shift keying (BASK) is generated, and the original code sequence is recovered by demodulation.

机械天线理论目前仍处于起步阶段，其辐射机制、场分布、调制方法等基础理论需要探索和完善。本文对基于旋转磁体的机械天线（RMBMA）的辐射机制进行了探索，建立了机械天线的等效辐射模型。利用该模型和旋转矩阵推导了机械天线的场公式，还研究了机械天线的空间直接调制方法。利用直流/交流伺服电机和钕铁硼磁体制作了两个原型天线，并进行实验以验证推导和分析的正确性。测量结果和仿真结果相互吻合。通过精确控制交流伺服电机的运动参数，产生了二进制幅移键控（BASK）信号，并通过解调恢复了原始码序列。