Modeling for RF noise suppressor using a magnetic film on coplanar transmission line

A finite-element method is applied to analyze the electromagnetic field and loss generation of a soft magnetic thin film on a coplanar transmission line for which the dimension of the magnetic film is designed to control the center frequency and bandwidth of the radio-frequency (RF) electromagnetic noise attenuation in the gigahertz range without external applied magnetic fields. The coplanar transmission line with characteristic impedance of 50 (omega) has total width, width of signal line, and thickness of 400, 50, and 3 (mu)m, respectively. The change of the magnetic field distribution, the induced surface current density on the coplanar transmission line, and hence the RF noise suppression by soft magnetic films are significant as a function of the width (502000 (mu)m) and thickness (0.1, 0.3, 0.5, and 1 (mu)m) of the magnetic film.