机械天线运动电荷和磁偶极子辐射研究

Theory Principle of the AMEBA Antenna Based on Radiation of Mechanical Motion of Electric Charge and Magnetic Dipole

自美国国防高级研究计划局(DARPA)推动基于机械的天线研究计划以来,机械天线(AMEBA)已成为日益关注的热点。传统的天线基于高频振荡电流产生电磁场和电磁波,而机械天线直接通过电荷、电流或者永磁体的机械运动产生变化的电场或磁场,进而产生电磁波。论文从经典电动力学理论出发,对机械天线的理论基础——运动电荷和运动磁偶极子的辐射问题进行了分析和研究,推导了辐射场的数学表达式。理论研究结果表明:运动电荷的辐射取决于其机械运动的加速度,运动磁偶极子或电流环的辐射取决于其磁矩对时间的二阶导数,作简谐运动的电荷或磁矩呈简谐变化的磁偶极子可以产生时谐电磁波的辐射。

Recently,much attention has been focused on a mechanically based antenna(AMEBA),since the research project of AMEBA is announced by the defense advanced research projects agency(DARPA),USA.Different to the traditional antenna of which radiation is based on the high-frequency oscillation of current,the electromagnetic wave of AMEBA is excited from mechanical motion of electric charge,current or ferromagnet.In this paper,radiation of the motion electric charge and magnetic dipole is formulated based on the classical electrodynamics theory.It's shown that radiation of the charge is depend on the accelarated-speed,while radiation of the magnetic dipole or current loop is determined by the two-order derivative of it's magneitc moment to time.The electric charge with harmonic motion and the magnetic dipole with harmonic variety magnetic moment can radiate time-harmonic electromagnetic wave.