RF integrated magnetic thin film noise suppressor on coplanar transmission line

Rf integrated noise suppressors were fabricated by integration of magnetic films using a microlithography process. CoNbZr magnetic films with various dimensions were stacked on coplanar transmission lines. The rf noise suppressor was composed of magnetic film (CoNbZr)/polyimide/Cu transmission line/seed layer (Ti/Cu)/glass substrate. The CoNbZr magnetic films (4πM_s ∼ 10 kG, H_k = 8.5 Oe, ρ= 120 μΩ cm, f_FMR = 0.8 GHz) were deposited by rf sputtering. The signal attenuation of the transmission line was estimated by extracting S-parameters (S₁₁, S₂₁) from a network analyser up to 20 GHz. In the case of 2000 μm wide, 15 mm long and 2 μm thick magnetic films, the magnitude of signal attenuation at the resonance (dip) point was increased greatly to about -56 dB compared with a coplanar transmission line without magnetic film. In the case of 50 μm wide, 15 mm long and 2 μm thick magnetic films, insertion loss and power loss except for the resonance frequency region was very small in comparison with that of 2000 μm wide magnetic films. These results are related to the ferromagnetic resonance and eddy current loss due to the dimension of the magnetic film on the coplanar transmission line with the 50 μm wide signal line.