Abstract: Electromagnetic wave eigenmode equation in one dimension periodic lossy medium is derived. It has been found that the solutions of the equation can be classified as a series of conduction and forbidden bands. Substituion of the real Re(K²) for complex K to symbolise modes shows the band structure clearly and facilitates classifing and comparing of the modes. The figures of the lowest two bands of TE wave and TM wave for a group of parameters are given by using numerical method. They are compared with electron energy band in periodic potential field.

Key words: one dimension periodic lossy media, electromagnetic wave mode, eigenvalue equation, eigenvalue, band structure