Evaluation of Transmission Characteristics of Differential and Common Modes of Parallel Two-Conductor Microstrip Lines with a Co-Zr-Nb Film

Abstract

The effect of sheet- and film-type electromagnetic noise suppressors on differential mode (DM) and common mode (CM) transmission characteristics in two parallel lines was investigated. Simple two parallel microstrip lines with a Co-Zr-Nb film were used as a test bench. The transmission characteristics of DM and CM were measured by 4-port network analyzer. The ferromagnetic resonance (FMR) and eddy current losses generated in the Co-Zr-Nb film were calculated by 3D full wave simulator, and the effects of these losses on the transmission characteristics were estimated. The results show that the transmission characteristics are different in DM and CM because the frequency characteristics of the losses are different according to the different FMR frequency in each mode. Furthermore, the feasibility of the application of the magnetic film as a frequency-selective CM filter is demonstrated by using the difference in frequency characteristics of loss of DM and CM.