The eigen permeabilities and eigen waves of the basic transmission modes arededuced,which play intrinsical roles in the propagation of plane waves in anunreciprocal medium.

• 导出了平面波在非互易媒质中传播时，起本质作用的本征导磁率和基本传输模式本征波，本征导磁率对应本征波中的传输常数。