Efficient full-wave characterization of microstrip lines fabricated on magnetized ferrites with arbitrarily oriented bias field

The spectral domain approach (SDA) is used for the full-wave determination of the propagation constant and characteristic impedance of microstrip lines fabricated on ferrite substrates with arbitrarily oriented bias magnetic field. Numerical problems arising from the numerical computation of the microstrip lines parameters for high values of the spectral variables are avoided by using asymptotically equivalent structures. The evaluation of the infinite integrals involved in the determination of the propagation constant is efficiently carried out by means of a technique based on the interpolation of the spectral dyadic Green's function. The numerical results obtained indicate that for every microstrip line fabricated on ferrite substrate there is a frequency region in which propagation is not feasible, the limits of this frequency region being strongly dependent on both the orientation and the magnitude of the bias magnetic field. Also, the authors show that for every frequency, both the propagation constant and the impedance of the microstrip lines can be adjusted over a wide range by varying the bias magnetic field magnitude.