Faculty Publications
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Item Performance of X-Band CMOS LNA with Broadband Approach for 5G Wireless Networks(Springer Science and Business Media Deutschland GmbH, 2021) Pottem, S.K.; Kabade, R.D.; Nikith, T.N.; Mondal, S.; Kumar, S.This paper presents a CMOS low noise amplifier (LNA) for X-band range of communication for 5G wireless networks. The proposed LNA consists of three stages of casade–cascode CS topology. A Chebyshev filter T-network stage is employed for broadband input impedance matching while cascode–cascade stage is followed for a higher gain. The current mirror topology is used to provide bias current and active load to the LNA. The LNA is designed and simulated using 180 nm UMC Taiwan process in cadence platform. The proposed schematic simulation achieved a gain higher than 15 dB for the range of 8 GHz to 12 GHz (X-Band) and a minimum noise figure (NF) of 4.2 dB at 12 GHz. The proposed differential LNA operates under 2 V power supply and layout using metal–insulator–metal layers. The design and layout are verified using DRC and LVS rules. © 2021, Springer Nature Singapore Pte Ltd.Item Room-temperature ultraviolet-ozone annealing of ZnO and ZnMgO nanorods to attain enhanced optical properties(Springer, 2020) Alam, M.J.; Murkute, P.; Sushama, S.; Ghadi, H.; Mondal, S.; Paul, S.; Das, D.; Pandey, S.K.; Chakrabarti, S.ZnO and ZnMgO nanorods have proven to be promising materials for sensing, UV and deep UV based optoelectronic applications. A major drawback of ZnO and ZnMgO based thin films and nanorods is the presence of native point defects which deteriorates their optical efficiency and becomes an impediment to their efficient device applications. The furnace and rapid thermal annealing processes have overcome this up to a great extent but being high temperature processes, they put many fabrication and technological limits in device fabrication. Especially keeping an eye on the future flexible devices, herein we report ultraviolet-ozone (UVO) annealing as a room-temperature, simple and cost-effective annealing method to improve the optical efficiency of ZnO and ZnMgO nanorods along with control of defect states. The ZnO and ZnMgO nanorods were grown by hydrothermal method and annealed in UVO irradiation. UVO annealing substantially improved near band emission and suppressed defect band emissions. It is found that zinc interstitial atoms migrate from the top portion of ZnO nanorods towards the bottom of nanorods after UVO annealing, resulting in reduced zinc interstitial defects in the top portion of nanorods. X-ray diffraction results showed improvement in structural properties. XPS results confirmed suppression of oxygen vacancies and zinc interstitials and improvement in lattice oxygen in the ZnO nanorods after UVO annealing. Optimum times of UVO annealing for ZnO and ZnMgO nanorods were 30 and 50 min respectively. These findings will be helpful for the further development of ZnO and ZnMgO nanorods based high performance optoelectronic devices and sensors. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Item Battery Storage-Based Novel Hybrid Islanding Detection Technique Using Lissajous Pattern Estimation(Institute of Electrical and Electronics Engineers Inc., 2022) Mondal, S.; Gayen, P.K.; Gaonkar, D.N.The reliability, uncertainty, and sensitivity of local islanding detection method for distributed generation (DG) system under diversified real-time scenarios and nonlinear loading conditions are not greatly explored. In this article, a new type hybrid islanding detection technique (IDT) is suggested, which reduces uncertainty and simultaneously improves reliability and sensitivity under different situations. In the technique, one detection parameter is defined, which is calculated from estimation of major and minor axes of Lissajous pattern (LP). Here, the evaluation of the parameter is done in two stages to avoid erroneous detection. In the first stage, the initiation of voltage transient is detected by LP. In the second stage, the active control via battery energy storage system (BESS) distinguishes nuisance tripping case from the islanding state. The extra active power injection/absorption via BESS also helps to identify islanding state at very near to zero power condition, i.e., sensitivity is enhanced. The detection time is found within 160 ms for different test cases, which is well below that of the acceptable upper value (2 s) specified in standard. The uncertainties in detection and threshold setting due to variations of harmonics and other operating conditions are removed in the proposed case, which is a distinct advantage. The Typhoon-HIL tool is used to carry out various case studies in real-time. Here, superior performances of proposed approach are observed in comparison with other state of the arts reported in the literature. © 1963-2012 IEEE.Item A Hybrid Islanding Detection Method Based on Lissajous Pattern Having Robust Performance Under Various Power Quality Scenarios(Institute of Electrical and Electronics Engineers Inc., 2023) Mondal, S.; Gayen, P.K.; Gaonkar, D.N.A fast, accurate, robust, and two-staged islanding detection technique (IDT) is proposed. It is the hybridization of second-order general integrator-frequency locked loop (SOGI-FLL), Lissajous pattern (LP), and active power absorption-cum-reactive power injection via dc-bus connected battery unit-based inverter. The LP is used to identify islanding condition on the basis of frequency variation of fundamental voltage. Here, the measured ac voltage signal is preprocessed by SOGI-FLL to obtain fundamental bus voltage under various power quality scenarios. This assures robust islanding detection by removing uncertainty, and thus, reliability is improved. The uncertainty effects due to the partial shading condition of the PV module (source-side disturbance) and weak grid-connected condition are avoided by dc-bus connected battery storage unit. Thus, it removes above-said limitations of the existing scheme. The LP-based detection within the nondetection zone is expedited due to active and reactive powers variation via controlling of the inverter and charging operation of the dc-bus connected battery unit. During the reactive power injection by solar inverter, active power is absorbed by dc-bus connected battery unit. In effect, an active power output of the inverter is reduced. Here, the reactive power injection at the reduced active power output condition of the inverter accelerates frequency variation allowing rapid islanding detection. The real-time experiments are carried out using Typhoon-HIL tools to compare the proposed method with other works reported in the literature. Improved performances under diversified scenarios are found in the proposed case. © 2007-2012 IEEE.Item Tungsten and fluorine co-doping induced morphology change and textured growth of spray-pyrolyzed SnO2 thin films viable for photocatalytic application(Elsevier B.V., 2023) Maharana, G.; Reddivari, R.; Yuvashree, J.; Mandal, D.; Mondal, S.; Kovendhan, M.; Fernandes, J.M.; Laxminarayana, G.; Joseph, D.P.Physicochemical aspects of numerous metal oxide based thin films are crucial for various optoelectronic applications. Cationic (W) and anionic (F) co-doping strategy into SnO2 thin film has been adapted in order to tune the optoelectronic parameters. X-ray diffraction pattern reveals successful doping of ‘W’ and ‘F’ into the SnO2 lattice and textured growth along (111) plane direction at the expense of suppression of the (211) plane. X-ray photoelectron spectroscopy confirmed the charge states of Sn4+, W6+, O2− and F1− elements present in the films. Scanning electron microscopy shows that tetragonal morphology of pure and F-doped SnO2 changes to a network-like feature upon ‘W’ co-doping and the elemental composition is also ensured. The contact angle measurement gives the surface wettability nature, which indicates all the films are hydrophilic. The 10 wt.% F-doped SnO2 shows a maximum transmittance of 89.36 % at 550 nm with a direct band gap of 3.82 eV. Electrical transport parameters are measured using linear four-probe and Hall effect techniques. Photocatalytic activity of methylene blue dye degradation showing a maximum efficiency for pure and solely F-doped SnO2 thin films are explained based on the obtained optoelectronic parameters. © 2023 Elsevier B.V.Item A Fast and Robust PLL Design with a Combination of Frequency-Adaptive Alpha-Beta-CDSC and SOGI(Institute of Electrical and Electronics Engineers Inc., 2025) Mondal, S.; Gayen, P.K.; Gaonkar, D.N.Recent research has focused on the enhancement of the prefiltering capability of phase-locked loops (PLL). The cascaded delayed signal cancellation (CDSC) PLL removes the low-order selective harmonic frequencies near the fundamental frequency. Here, a frequency-adaptive time delay unit is used to cope with frequency and phase variations of voltage. The high-frequency signal arising due to the frequency-adaptive loop cannot be mitigated. In effect, the transient response of adaptive CDSC-PLL shows a significant irregular pattern. Therefore, this article suggests the use of a second-order generalized integrator (SOGI) after the adaptive CDSC unit to improve the transient profile of frequency response. In the design, the high gain (K = 5.4) of SOGI is chosen to quickly settle the response of PLL at the expense of its ignorance of lower-order harmonics near the fundamental frequency. However, the lower-order harmonics are selectively eliminated by the CDSC unit. So, both prefilters complement each other's filtering capabilities. Additionally, the suggested prefilter provides improved noise immunity and eliminates DC offset via the SOGI unit. The linearized model and tuning procedure for the different control parameters of the proposed PLL are described. The real-time hardware-in-loop tests are executed to justify the optimum performance of the proposed PLL. © 2024 IEEE.