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In this study, a polymer nanocomposite is synthesized using magnetic and conducting fillers for enhanced electromagnetic interference (EMI) shielding. Alfa-ferrite (α-Fe2O3) nanoparticles with minimal multiwalled carbon nanotube (MWCNT) as low as 5 weight % in combination with variable concentrations of graphene nanoplatelets (GNP) are used as fillers in low-density polyethylene (LDPE) polymer matrix. Nanofillers and the polymer matrix are characterized by various techniques such as XRD, SEM, color mapping, EDAX, TGA, etc. The EMI shielding efficiency of the LDPE-based nanocomposites is tested using Vector Network Analyzer (VNA). The results showed that composite with LDPE:MWCNT:GNP:α-FO-50:5:40:5 displayed enhanced EMI shielding (in X-band (8.2–12.4 GHz) compared to other concentrations studied. This is due to the superior ohmic, dielectric, and magnetic losses at this particular composition and to the synergism amongst the filler. An attenuation of 99.99% was achieved for 5% α-Fe2O3. The mechanistic aspects of the shielding are discussed using permittivity, conductivity, and attenuation.

A shared ground shared radiator with wide angular coverage for mmWave 5G smartphones is proposed in this paper. A four-element corporate-fed array with conventional impedance matched power divider is designed. Stepped impedance transformers are integrated with the corner most elements to achieve pattern diversity with wide angular coverage without significant compromise in gain. The proposed three-port shared radiator conformal commercial antenna could be easily integrated with commercial mmWave 5G smartphones. All the three ports’ excitations operate in the 28 GHz band. Radiation pattern bandwidth of the multi-port system is high. The gain variation is from 6 to 11 dBi amongst the ports and across the operating spectrum. The highest mutual coupling is 10 dB, in spite of the electrically connected structure. The proposed shared radiator element has a wide angular coverage of 100°, maintaining high front-to-back ratio when the respective port is excited. Simulation and measurement results for the proposed structure are illustrated in detail.

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