Effects of the magnetic layer length on the high-frequency characteristics of an integrated-type coplanar wave-guide transmission line

Integrated-type electromagnetic noise suppressors, based on a coplanar wave-guide transmission line, are investigated, incorporated with a SiO2 dielectric and a nanogranular Co-Fe-Al-O magnetic thin film. The length of the magnetic thin film is varied from 2 to 15 mm, while its thickness and width are fixed at 1 and 50 μm, respectively. In the measurement frequency range of 0.1-20 GHz, no obvious resonance is seen at the shortest length of the magnetic thin film, but resonance behavior occurs at larger length. A very clear resonance occurs at the largest length of 15 mm, where the resonance frequency is ∼10 GHz and the signal attenuation is as large as -20 dB. The observed resonance frequency is much higher than the ferromagnetic resonance frequency and the main mechanism of loss generation is found to be L-C resonance