Measurement and Magnetic Countermeasure Methodology to Deal with Inverter Noise

In this paper, the influence of unnecessary radio waves at the receiver circuit of a cell phone handset is suppressed by a new magnetic material in order to contribute to the technology for reliably sharing these different systems at frequencies from 700 MHz to 6 GHz where many radio waves systems are concentrated. The material used is called hexagonal ferrite and is widely used as a permanent magnet material in general. Since this material can generate magnetic losses in a frequency selective manner in and above the SHF band, the fine particles hexagonal ferrite are mixed with a polymer binder to form a powder composite and applied on the wiring on PCB. This component was used as a frequency variable resistor for conduction noise suppression. Performance verification was evaluated by input loss ratio, Ploss / Pin, on the microstrip line based on IEC 62333–2. It became clear that this new noise suppressor has excellent noise suppressing function in the GHz band.