EMI shielding is designed to absorb radio and other EMI waves. Nowadays, EMI is becoming more and more of a problem, so how to choose the best EMI shielding method?EMI shielding methods in FPC can include copper plating, conductive silver ink printing, and EMI shielding film bonding.
Copper plating: Copper plating is a traditional shielding method that has been commonly used in the past for manufacturing FPCs. However, copper is not suitable for applications that require a high degree of flexibility because it tends to crack during circuit bending or folding, or create burrs during die cutting. Thin cross-shaded copper layers would be a good choice for multilayer flexible PCBs.
Conductive Silver Inks: Silver inks are an excellent method of EMI shielding. Modern metallic silver inks and coating technologies ensure the clean and proper functioning of chips on high-frequency boards, as well as their ultra-high-speed data transmission. Conductive silver inks are sometimes used for flexible PCB designs, but they are the most expensive and have the longest processing time of the four methods.
Metal Shell: Metal Shell is a classic EMI shielding method used primarily for rigid PCBs and rarely for flexible circuits. It seems to be obsolete in FPCs because it does not meet the requirements of miniaturization. As electronics become smaller and smaller, metal enclosures are ineffective on such a small scale. In addition, specific areas of the FPC will lose their flexibility if a metal enclosure is used.
EMI Shielding Film: EMI shielding film is becoming increasingly popular in the design of flexible PCBs and rigid-flexible boards. With EMI shielding film designs, flexible PCBs have the best flexibility and thinnest overall thickness. Compared to silver ink printing and copper layer designs, the cost of flexible PCBs can be lower while the shielding capability can be slightly higher.EMI shielding film offers several advantages in terms of shielding performance, flexibility, cost, and processing cycle time. It provides enhanced shielding performance for transmitting high-frequency signals and a high degree of flexibility to prevent circuit breakage during flexing and can be used as an alternative to copper layer designs, resulting in cost savings without compromising board flexibility.
