電磁ノイズ抑制体における電力損失の電磁界シミュレ一ション

摘要

Electromagnetic simulation of eddy currents and ferromagnetic resonance (FMR) losses in a thin film noise suppressor are discussed based on the 3D finite element method and 3D equivalent circuit network analysis models. Radio frequency (RF) noise power is dissipated into heat by these losses. The eddy currents have in-plane and out-of-plane loops, whose losses are a function of sheet resistance, i.e., the ratio of material resistivity to its thickness. The FMR frequency shifts from the original to higher frequencies in electronic devices because of demagnetization caused by local currents by wiring. This shift can be calculated with an electromagnetic field simulator based on Maxwell's equations, although the relative permeability and FMR frequency is defined by the Landau-Lifshitz-Gilbert (LLG) and Kittel's equations. These analyses were applied to an on-chip integrated noise suppressor, which exhibited a 10-dB improvement in long term evolution (LTE)-class cellular phone receiver circuit sensitivity.