《18 Electromagnetic Shielding of Transceiver Packaging Using Multiwall Carbon Nanotubes》.pdf

Chapter 18 Electromagnetic Shielding of Transceiver Packaging Using Multiwall Carbon Nanotubes Wood-Hi Cheng(*ü ), Chia-Ming Chang, and Jin-Chen Chiu 18.1 Introduction The widespread deployment of low-cost optical access networks for fiber-to-the- home (FTTH) applications will necessitate a considerable reduction in the cost of key components such as optical transceiver modules. Optical transceiver module costs are primarily dependent on their packaging. Owing to its low-cost nature and ease of manufacture, plastic packaging technology has been considered as one of the major choices for reducing the costs of fabricating optical transceiver modules for use in FTTH applications [1 – 5] . However, plastics alone are inherently trans- parent to electromagnetic (EM) radiation, and hence provide no shielding against radiation emissions. To improve EM shielding for plastic packaging, electronic conductive properties have to be added into the plastic hosts. Currently available techniques for electromagnetic interference (EMI) shielding include conductive sprays, conductive fillers, zinc-arc spraying, electroplating or electrolysis plating on housing surfaces, modifications of electrical properties during the molding stage, and other metallization processes. Among these methods, the most popular one for EM shielding is to compound plastics with discontinuous electronic conduc- tive fillers, such as metal particles, metal flakes, stainless fiber, graphitized carbon particles, graphitized carbon fibers, metal-coated glass, and carbon fibers [6 , 7] . Experimental evidence has shown that carb