
Electromagnetic interference (EMI) is an escalating concern in the modern era of electronics. As such it has become a critical area to study while designing and packagingelectronics. With the growing volume of electronic devices and increasing processor frequencies, the electromagnetic environment is becoming ever more congested resulting in need for adequate EMI shielding. Further, due to the steady growth of communication technology and adverse effects of electromagnetic radiations on human body and electronic devices, it is essential to reduce the Electro- Magnetic Interference (EMI) and its impact. The desire for high performance, combined with reductions in size, weight andmanufacturing cost suggests that polymers could be ideal material especially for electronic housings. Unfortunately polymers generally do not provide shielding fromelectromagnetic waves because of their insulating nature. In this context, Electroless Alloy (Ni-P-W) Coated Nanocenosphere in and Acrylonitrile Butadiene Styrene (ABS)and Poly methyl Methacrylate (PMMA) composites have been investigated for their EMI shielding effectiveness. The strategy is to render the polymer conductive by dispersing Nickel-Phosphorous-Tungsten alloy coated Nanocenospheres along with Conductive fillersin the polymer (PMMA/ABS) which promotes wave absorption. All the studies have been made on polymer composite sheets with electroless alloy coated Nano-cenospheres. In the present study, EDX (Energy Dispersive X-Ray) analysis confirmed the presence of Ni, W and P on the coated Nanocenosphere particles substantiated by Phase analysis using XRD (X-Ray Diffractometer). SEM (Scanning Electron Microscope) analysis was conducted to study the size, shape of the coated particles and to observe the distribution of these particles along with conductive fillers in polymer matrix in the composite sheet. This paper discusses theprocessing methods, electrical surface resistivity and its correlation with EMI shielding. In the current formulation, shielding effectiveness of approximately 35 dB at a frequency of 1GHz wasachieved for Electroless alloy coated Nanocenospheres in ABSpolymer, which is higher than that of PMMA polymer. Further, the effects of coated Nanocenosphere particle size and distribution in polymer matrix have been discussed.