Novel Type of Conducted Noise Suppressor in GHz Range Using Ferrite-plated Film

抄録

Two types of conducted noise suppressors, which dissipate noise current energy before radiated as noise waves, were developed using Ni-Zn ferrite films synthesized from an aqueous solution. In the “sheet type," Ni-Zn ferrite films of 5 μm thickness were deposited on polyimide sheets. In the “direct-deposition type," the films were deposited directly on to the microstrip line fabricated on printed circuit board (PCB). The transmission loss ΔP_lossper thickness for the “sheet type" and “direct-deposition type" were 16 and 20 times larger, respectively, than that for commercialized composite noise suppressing sheets. Both types of ferrite-film noise suppressors exhibited reflection coefficient S₁₁ small enough (< -10 dB) to be applied as conducted noise suppressors up to 10 GHz.