BITS Faculty Publications
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Item Optimizing material choices for flexible pressure sensors driven by triboelectric nanogenerators(IEEE, 2025-04) Gupta, NavneetThis study shows the investigations on optimal dielectric material for self-powered flexible pressure sensors (SPFPSs) based on triboelectric nanogenerators (TENGs) using multiple criteria decision-making (MCDM) methods. Specifically, we utilized technique for order preference by similarity to ideal solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) techniques to identify potential dielectric materials. Several materials attributes, such as surface charge density, coefficient of friction, and dielectric constant, are examined to find out the best dielectric material. Through the TOPSIS and VIKOR ranking systems, we determined that polydimethylsiloxane (PDMS) is the most suitable dielectric material for TENG-based SPFPSs. The result presents a strong alignment across material selection methods and simulations that validates the robustness of our proposed outcomes.Item Fabrication of novel thin film capacitor based on PVA/ZnO nanocomposites as dielectric material(Springer, 2020-11) Nair, Sindhu S.A three-layer thin film capacitor was designed and fabricated with PVA/ZnO nanocomposite as dielectric material. Addition of ZnO nanoparticles showed change in dielectric constant, which varied with frequency and weight percentage. ZnO nanoparticles of weight percentage of 0.5% is chosen for the synthesis of nanoparticles with a grain size of 54 nm, using cost-effective and simple co-precipitation method. It is a low-cost method for large-scale production without impurities. The agglomeration was reduced by adding the starch molecules so that the O–H functional groups could hold together to the nanoparticles at the earlier nucleation stage and can be removed when purification by centrifugation is done. Fourier-transform infrared spectroscopy analysis showed peaks due to the O–H groups in the polymer backbone, CH2 asymmetric and symmetric stretching, C–C stretching and Zn–O stretching, respectively, indicating formation of the proper film. From the profilometer, the thickness was calculated as 195.73 nm for the dielectric film. The fabricated device showed capacitance of 210 nF m−2 in par with the theoretical value (254.451 nF m−2) at 298 K.Item Carbon Nanotube Field Effect Transistor: Basic Characterization and Effect of High Dielectric Material(IJRTE, 2009-11) Mishra, Rashmi RanjanAs the scaling of Si MOSFET approaches towards its limiting value, new alternatives are coming up to overcome these limitations. Carbon nanotube field effect transistor (CNTFET) is found to be one of the most promising alternatives for bulk Si MOSFET. In this work we have simulated a cylindrical CNTFET. Based on the simulation results both output and transfer characteristic curves are plotted and analyzed. We have also studied the effect of different dielectric materials used as gate insulator.Item Pentacene Organic Field Effect Transistors on Flexible substrates with polymer dielectrics(IEEE, 2007) Rao, V. RamgopalPentacene organic field effect transistors are fabricated using polymethyl methacrylate (PMMA) as a gate dielectric on flexible polymeric substrates like the indium tin oxide coated polyethylene terephthalate (ITO coated PET), and polyethylene napthalate (PEN) in top contact configuration. The ITO and aluminium (evaporated on PEN) act as the gate materials for the OFETs. The devices on ITO coated PET show electron mobility up to 0.07 cm 2 /V-s and the on/off ratios in the order of 10 3 .Item A strip loaded dielectric resonator antenna for circular polarisation(Wiley, 2006-04) Kumar, A. V. PraveenThe paper presents an experimental investigation of a cylindrical dielectric resonator antenna (DRA) with a conducting strip loaded on its top surface enabling circular polarisation. A simple 50Ω microstrip transmission line excites the antenna. The reflection, polarisation, and radiation characteristics of the antenna are studied. The antenna exhibits circular polarisation with an axial ratio (AR) < 3 dB over a bandwidth of 3.14% and a beam width of 60°. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1354–1356, 2006; Published online in Wiley InterScienceItem Dielectric material selection of microstrip patch antenna for wireless communication applications using Ashby's approach(Cambridge University Press, 2014-07) Gupta, Navneet; Kumar, RajneeshIn this paper, material selection has been done for dielectric substrate material in microstrip patch antenna (MPA) for three distinct classes of wireless communication applications using Ashby's approach. This material selection procedure is based on the creation and evaluation of Ashby's chart of different material indices. These material indices in turn affect the device performance indices, which decide the best possible dielectric material to be used as substrate for MPAs. In this work, quality factor, relative permittivity, and temperature coefficient of resonant frequency are chosen as material indices of MPA's dielectric substrate to get relevant performances. Ashby's selection chart shows that 0.75MgAl2O4–0.25TiO2 material for millimeter waves applications, Ca[(L1/3Nb2/3)0.85Ti0.15]O3−δ for mobile base station applications, and (Ba0.95Ca0.05)O–Sm2O3–4.5TiO2 ceramic for mobile phone miniaturization applications are the promising materials that allows best overall performance in MPAs for wireless communication.Item Investigation on microwave dielectric materials for dielectric resonator antennas(IOS, 2015) Gupta, NavneetIn this paper, a theoretical and practical investigation on microwave dielectric materials for wideband dielectric resonator antennas (DRAs) is presented. Due to the variety of materials available to antenna designers, a proper technique to select the best possible material is required. In this paper Ashby's material selection methodology is used for dielectric material based antenna systems. Four primary performance indices, impedance bandwidth (BW), the size of the antenna (λ), radiation efficiency (η) and resonance frequency (f_{0}), are used to obtain the desired performance. The selection chart shows that Roger TMM10, (ε_{r}= 9.8) is the most suitable material followed by "Roger's TMM10i and RO3010" for DRAs to provide the best performance for wideband applications. Performances of antenna are verified with rectangular and hybrid design of DRA in terms of reflection coefficients, radiation pattern, gain and efficiency. Theoretical work is compared with the simulation and the close agreement between the two, confirm the validity of this study.Item Investigation into gate dielectric material using different optimization techniques in carbon nanotube field effect transistors(Journal of Micromechanics and Microengineering, 2019) Navneet, GuptaThis paper presents an analysis of gate dielectric materials using different optimization techniques for carbon nanotube field effect transistors. The selection of the best gate dielectric is done using multi-criteria decision-making methods, i.e. Ashby's, TOPSIS (technique for order preference by similarity to ideal solution) and VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje in Serbian). The selection criteria for the best dielectric material are based on various material indices which include relative dielectric constant (εr), energy band gap (Eg), conduction band offset and coefficient of thermal expansion. This analysis concludes that lanthanum oxide (La2O3) is the most promising dielectric material, followed by HfO2. All these material selection methodologies converge on the same results. This result is compared with the experimental findings, and the close match between analytical and experimental results confirms the validity of this study.