抄録
Configurations of a yoke and a permanent magnet was optimized in a down-sized micro-strip isolator which was achieved by utilizing a yttrium iron garnet ferrite single crystal with a very small full-width at half-maximum of ferromagnetic resonance curve. Combination of a 0.1-mm-thick iron yoke and a 0.1-mm-thick SmCo type permanent magnet could produce magnetic bias field of 500 Oe which enables the isolator to operate at 1.85 GHz in above resonance mode. The size of the designed isolator was 4x3.5x1 mm which was 1/90 of the conventional micro-strip isolator which operates in below resonance mode. Superior non-reciprocal transmission characteristics of the isolator were also proven by high frequency electromagnetic simulation based on a 3D finite-element-method.
