After using the full-wave method and the cold plasma model,the influence of the poloidal magnetic field on the conversion process from ordinary mode to extraordinary-mode in the electron cyclotron range of frequencies has been discussed.The results show that in the case of N y=0,when the electron cyclotron wave emitted by the antenna propagates in the plasma,the presence of the poloidal magnetic field will cause the region of evanescence to exist all the time,so the mode conversion of 100%can’t be achieved.Moreover,as the intensity of the polo...