Analysis of conduction noise attenuation by magnetic composite sheets on a microstrip line by the finite element method

Abstract

Conduction noise attenuation by magnetic composite sheets along a microstrip line has been analyzed by using an electromagnetic field simulator that employs the finite element method. The simulation model consists of a microstrip line with planar input/output ports and noise absorbing materials of large magnetic loss (magnetic composite sheets containing iron flake particles as absorbent fillers). The input port is excited by a TEM-mode wave with a characteristic impedance of 50 Ω. Reflection and transmission parameters (S11 and S21) and power loss are calculated as a function of frequency with variation of the sheet size and thickness. The simulated values are in good agreement with experimental results and the estimated size dependency of power absorption is consistent with transmission line theory. It is proposed that the simulation technique can be effectively used in the design and characterization of noise absorbing materials in high-frequency transmission lines.