Effect of nonuniform magnetic field on left handed ferrite microstrip line

Transmission characteristics of the left handed (LH) ferrite microstrip line are significantly affected by the nonuniform bias magnetic field H. , because strip conductors must be fabricated on the edge of the ferrite substrate. Three dimensional analysis is performed taking into account the nonuniform H_in caused by the demagnetizing effect in the ferrite substrate. Analyzed result shows that, the nonuniform H_in expands the frequency range and contributes to the improvement of the nonreciprocal characteristic of the LH ferrite microstrip line. Measured result more than 20 dB isolation with 3.2 dB insertion loss and 1.52 GHz bandwidth are almost corresponding to the theoretical result.