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Broadband electromagnetic shielding and dielectric properties of polyaniline-stannous oxide composites Muhammad Faisal • Syed Khasim

Received: 17 October 2012 / Accepted: 15 January 2013 / Published online: 24 January 2013 Ó Springer Science+Business Media New York 2013

Abstract Conducting polyaniline-stannous oxide (PAniSnO) composites were synthesized by the in situ polymerization of aniline in the presence of SnO. The composites formed were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As there is a greater need for materials with electromagnetic interference (EMI) shielding properties over a large operating frequency band, the present study highlights the dielectric and EMI shielding response of PAni-SnO composites in the microwave frequency range from 8 to 18 GHz (X and Ku bands). All the computations were based on microwave scattering parameters measured by transmission line waveguide technique. The EMI shielding effectiveness (EMI SE), return loss, microwave absorption and dielectric properties of the PAni-SnO composites were evaluated for various wt% of SnO (10, 20, 30, 40 and 50 wt%) in PAni. In X-band, the composites exhibits EMI SE in the range -18 to -23 dB, with microwave absorbance of 70–83 % and in the Ku-band, the composites exhibits EMI SE values of -17.5 to -22.5 dB with 67–85 % absorbance. Our investigations reveal that the PAni-SnO composites are potential candidates for EMI shielding applications for both the X and Ku bands.

M. Faisal  S. Khasim (&) Department of Physics, PES Institute of Technology, South Campus, Bangalore 560 100, Karnataka, India e-mail: [email protected] S. Khasim Department of Physics, University of Tabuk, Tabuk 71491, Kingdom of Saudi Arabia

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1 Introduction Electromagnetic interference (EMI) is the radiated or conducted energy that negatively changes an electric circuit’s performance. EMI shielding and microwave attenuation materials are receiving enormous interest to protect electronics, instrumentation and environment in commercial, industrial, health care and defense applications in the full range of the EMI frequency spectrum [1–5]. The interference across communication channels, automation and processing controls result in loss of valuable time, energy and resources. Hence, EMI has been addressed under electromagnetic compatibility (EMC) regulations by governments and organizations around the world (IECTC77, IEC-CISPR, FCC-20780, MIL-STD-461/462, etc.) [6–8] to focus on the key issues related to EMI shielding. One of the important parameters in characterizing EMI shielding materials is the electromagnetic interference shielding effectiveness (EMI SE) values in the frequency range of interest [2, 9]. In the past, metals and their composites which exhibit high conductivity and enhanced dielectric constant were the most common materials for EMI shielding [10, 11]. But their disadvantages are heavy weight, physical rigidity and susceptibility to corrosion