On the Characteristic Impedance Definition of Nonreciprocal Waveguides

In the field of microwave integrated circuits (MIC) the problem of characteristic impedance defini tion has been treated in numerous papers. However, in all publications up to now reciprocity has been assumed. In the present paper, problems concerning the characteristic impedance defini tion of nonreciprocal lines are discussed. Especially for slot-and fin-lines and components with ferrite substrate these considerations are of great interest because in these cases a strong nonreciprocity occurs. As a result it will be shown, that usually only the reflection definition of the characteristic impedance is consistent wi th the line theory, the S-parameter concept and the reciprocity theorem for gyrotropic media.