A new magnetizing concept of time-harmonic change is introduced and an expression on ferrite permeability tensor μ （r

θ

Ωt） is derived

which is variable with time t and coordinate components r

θ. Under the condition of quasi-static state magnetizing

the process of propagation of electromagnetic wave in a ferrite circular waveguide

which is acted by a transverse rotating field

is discussed. It shows that the periodically coupled waves are caused between two dominant propagating modes

H11 odd-mode and H11 even-mode. The coupling coefficient c and the propagating coefficients βo and βe are obtained

and they are variable with time t. Finally

an approximate structure to realize ferrite rotating-wave-plate is presented

and its application is also explained briefly.