Design of EMI/RFI suppression on LCD panel flexible printed circuit board for smartphones

This paper presents a design methodology of EMI/RFI suppression by SI/PI simulation at smartphone applications. In smartphones, the high speed transmission lines of display serial interface (DSI) at LCD panel are designed on a 2-layer flexible printed circuit (FPC) board. Serious simultaneously switching noise and interference are appeared to distort the GSM communication channels. In this paper, we design the FPC with optimized current return paths and decoupling capacitors by SI/PI simulation. This solution achieves 4 dB noise suppression at GSM-1900 band without cost increasing on the FPC design.