Faculty Publications
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Publications by NITK Faculty
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Item Multifunctional Polypyrrole/Multi-Walled Carbon Nanotube Composite Material: Dielectric, Humidity Sensing and Broadband EMI Shielding Properties(Pleiades journals, 2021) Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M.Abstract: Conducting polymer composites with suitable combination of two components in nanoscale are expected to facilitate wider applications of composites. In this study, polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) nanocomposites prepared by in situ chemical oxidative polymerization were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV–Vis spectroscopy. The electrical and dielectric properties were investigated using complex impedance technique. Complex dielectric permittivity, complex electric modulus and complex impedance variations were studied in the frequency range of 10 Hz–1 MHz. The dielectric attributes and conductivity data of different nanocomposites analyzed as a function of frequency revealed that the incorporation of MWCNT phase into polypyrrole matrix affects the electrical and dielectric properties of the composites. Humidity sensor measurements show that PPy/MWCNT can be effectively optimized as candidate for humidity detection. The nanocomposites were also studied for broadband EMI shielding applications by characterizing the materials in the 12?18 GHz (Ku band) to understand the shielding properties. The absorption dominant shielding effectiveness (SE) observed in the range of ?13 to ?15 dB was stable with visible variation with varying concentration of MWCNT in PPy. The experimental results of dielectric characterization, humidity sensing and EMI shielding response reveal that PPy/MWCNT composite can be suitable multifunctional material for various applications. © 2021, Pleiades Publishing, Ltd.Item Graphene-Oxide-Coated Flexible Fabric Antenna Sensor for Contact-Free H2O Sensing(Institute of Electrical and Electronics Engineers Inc., 2024) Singh, V.P.; Kandasamy, K.; Rahman, M.R.This article presents a flexible antenna sensor on denim jeans fabric for H2O sensing. A small defected ground structure is developed on the copper ground plane of the antenna. Graphene oxide (GO) is coated on the defected ground for sensor applications. The flexible antenna sensor with GO coated on a defected ground plane resonates at 5.52 GHz. The resonance frequency of the proposed antenna changes linearly with the H2O content. The frequency sensitivity of the denim fabric antenna sensor is ≈203 MHz/10% relative humidity (RH). The denim fabric antenna sensor has a measured phase sensitivity of 40° per 10% RH. The flexible antenna sensor gives a linearity of 98.28%. The designed antenna sensor can distinguish between fresh and dried grapes by H2O detection. © 2001-2012 IEEE.Item Graphene Oxide Assisted Humidity Sensing Antenna Sensor(Korean Institute of Electrical and Electronic Material Engineers, 2025) Singh, V.P.; Kandasamy, K.; Rahman, M.R.Abstract: In this paper, a graphene oxide (GO) coated substrate material is electrically characterized. The permittivity, loss tangent, permeability, and resistance are measured. A planar antenna with slots is designed on an RT/Duroid 5880 substrate. A thin layer of graphene oxide is coated on the identical slots of the planar antenna. The GO-assisted antenna sensor resonates at 2.51 GHz frequency. The graphene oxide-based antenna sensor performs contact-free sensing of relative humidity. The frequency sensitivity is approximately 17.5 MHz/10%RH. The design sensor gives a 93.50% linearity. The limit of detection is 30.55 RH%. Graphic Abstract: (Figure presented.) © The Korean Institute of Electrical and Electronic Material Engineers 2024.