Micropatterned high permeability films with narrow bandwidth resonance loss for the band stop filter

In this work the micropatterned CoNbZr films designed for the band stop filter are reported. It was already reported that a 400-mu m-wide coplanar line equipped with a 4-mm-wide CoNbZr film exhibits band stop characteristics, but practically the width of the film must be about the same size as the signal line. This limited width of the micropattern gives rise to dispersion of the shape anisotropy, resulting in degradation of band stop characteristics. Here we fabricated 150-mu m-wide patterned films with adjusted edge dimensions which widths have been enlarged from 20 to 40 mu m that were optimized on the permeability database. The resonance loss profile for the adjusted pattern is compared with that of a film without adjusted edges. The half width is appreciably decreased from 2.2 to 0.77 GHz. In conclusion an improvement of the resonance profile of micropatterned films was achieved by optimizing the edge dimensions. This will enable us to utilize magnetic films for more downsized signal lines. (C) 2006 American Institute of Physics.