自由空间中天线近区场的类消失态超光速现象

The Evanescent-state Like Superluminal Phenomenon of Near-field in Free Space

近年来不断有报道说,自由空间中在近场条件下电磁波可以超光速行进。实验中也观测到自由空间中的负波速现象。本文用类消失态原理和超前波理论对此作出解释。通过比较和鉴别,研究了消失场与天线近场的特性。因此我们得到了一种统一的认识和理解,它涵盖了近场超光速性、消失态电磁现象、Maxwell方程超前解、负波速。

Recently,it has been reported that near-field EM-waves travel at what appears to be superlumi- nal velocity in free space. And then, experimental observation of the free space negative wave velocity was presented. In this paper, that phenomenon is explained by the principle of evanescent-state like and the theory of advanced waves. Only by comparing can one distinguish the difference, we study the special fea- tures of the evanescent fields and the near-region field in free space. Then we reach a common under- standing about the near-field superluminality, EM phenomenon in evanescent state, advanced solution of Maxwell equation, and the negative wave speed.