Estimation of high-frequency loss properties through analytical calculation for semiconducting soft magnetic films in a near-field electromagnetic wave

Abstract

Gigahertz frequency characteristics were appraised by theoretical calculation based on a modified Landau–Lifshitz–Gilbert equation in order to examine the effect of electromagnetic induction and artificially controlled shape anisotropy in micropatterned magnetic films. Electromagnetic loss behaviors and magnetic fields of semiconducting soft magnetic films on a coplanar transmission line were numerically analyzed using a finite-element based electromagnetic solver. The combined relative permeability due to the electromagnetic induction and demagnetizing effect showed to be highly dependent on electrical resistivity and film thickness. Higher resistivity films at the same thickness of 2 μm showed higher loss in power and lower reflection because of the reduced electromagnetic induction. Thinner magnetic films at the same resistivity of 100 μΩ cm exhibited lower reflection due to the reduced electromagnetic induction and maxima of the reflection shifted to higher frequencies because of demagnetization associated with the structure of magnetic flux path. A severe increment of the radiated electromagnetic noise with decreasing resistivity was caused by the reflection of the radiated noise from the surface of the low resistivity films on the coplanar line in gigahertz frequency bands. A slight increase in the radiation noise with increasing thickness at the same resistivity confirmed to be caused by the increased reflection.

Highly Bendable and Durable Transparent Electromagnetic Interference Shielding Film Prepared by Wet Sintering of Silver Nanowires

“…Transparent EMI shielding films for flexible devices must exhibit high EMI shielding effectiveness (SE), high visible-light transmittance, high flexibility, ultrathin, lightweight, and excellent durability. − However, EMI shielding materials that satisfy all these criteria have not yet been developed. The performance of an EMI shielding material strongly depends on its electrical conductivity, permeability, thickness, and the EM frequency of interest. − Above all, to develop a superior flexible transparent shielding film, the material must have improved electrical conductivity, which is an intrinsic material characteristic, while maintaining a high degree of visible-light transmittance.…”