本文对一种基于场致发射阴极阵列（FEA）的太赫兹辐射源的物理机理进行了理论分析和粒子模拟验证．采用场匹配法分析了器件的高频场结构，确定π模作为器件的最优工作模式；利用线性理论分析了器件的注波互作用过程，揭示了高频场对FEA阴极发射电流的预调制作用以及电子在阴阳极间隙的渡越时间效应是器件起振的物理原因；分析得出了丌模起振条件；粒子模拟结果与理论分析具有较好的一致性．%The micro-vacuum electronic device is one of the most promising sources for the generation of high power THz-wave radiations. In this paper, the systematical theoretical analyses and computer simulations on the physical mechanism of a kind of micro-vacuum electronic THz radiation source based on the cathode of field-emission array （FEA） are carried out. The mode matching method is used to study the electromagnetic characteristics of the structure, and rt-mode is confirmed to be an optimal operation mode for its field distribution. Linear theory （small signal theory） is used to analyze the beam-wave interaction of this kind of source, and the starting condition of the ~-mode oscillation is derived. The premodulation of electron beam emitted from FEA and the electron transit time effect in the interaction gap are the physical cause of the electromagnetic oscillation. These results are well verified by the computer simulations.
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