Propagation in Ferrite-Filled Microstrip

The propagation constant of a ferrite-filled microstrip is measured as a function of the longitudinal static magnetic field, The results agree with the analysis by Van Trier of the infinite parallel plane waveguide filled with gyromagnetic media. The analysis is extended to anisotropies greater than 0.5. A simple relationship between propagation constant and anisotropy for the quasi-TEM mode with small spacing (X<<lambda_g) is noted. Cutoff spacings for higher modes are calculated. An apparatus for the measurement of propagation constant independently of interface reflections is described.