Shielding effectiveness of multi-wall carbon nanotube composite

A novel polymer-based multi-wall carbon nanotubes (MWCNT) with high shielding effectiveness (SE) is proposed. The MWCNT composites are tested to evaluate the electromagnetic (EM) shielding against emitted radiation from the plastic packaging. The results show that the SE of MWCNT composites exhibit 38 similar to 45 dB in far field and 28 similar to 40 dB in near field at a frequency range of 1 to 3GHz. The MWCNT composites with their good SE are potentially suitable for use in low-cost optical transceiver modules with low electromagnetic interference (EMI). Introduction: The widespread deployment of low-cost optical access networks for fiber subscriber loop 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 packaging. Owing to its low-cost nature and ease of manufacture, plastic packaging technology has been considered to be one of the major choices for reducing the costs of fabricating optical transceiver module for use in lightwave transmission systems(1-2). Electronic appliances are usually housed in plastic packaging. Plastics alone are inherently transparent to electromagnetic radiation and provide no shielding for EMI. Therefore, metal-like properties have been added to plastics to insure adequate EM shielding for electronic plastic packaging applications. Due to the fact that the electronic and mechanical properties of carbon nanotubles (CNTs) are remarkable, the CNTs have been the focus of considerable research and development for use in nanoscale electronic and optoelectronic applications, such as integrated circuit (IC) interconnections and optical emission devices. In this study, a novel polymer-based multi-wall carbon nanotubes (MWCNT) with high shielding effectiveness (SE) is demonstrated. The MWCNT composites are potentially suitable for use in low-cost optical transceiver modules with low EMI. Measurements and Results: The EM shielding materials of plastic composites consisted of MWCNT mixed with liquid crystal polymer (LCP). The SE of the plastic composites are studied both from the far-field and near-field sources approaches. The shielding measurements of plastic composites in the far-field source were based on the ASTM D4935 method(1-2). The measured result of SE versus frequency for MWCNT composite is shown in Fig. 1. The SE was measured at 38-45 dB in the frequency range of I to 3 GHz.