Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
3 results
Search Results
Item Widely tunable low-pass gm ? C filter for biomedical applications(Institution of Engineering and Technology journals@theiet.org, 2019) Jayaram Reddy, J.R.M.; Laxminidhi, T.This study presents a fourth-order, low-pass Butterworth transconductor–capacitor gm ? C filter with tunable bandwidth for biomedical signal processing front-ends. An architecture has been proposed for realising very low transconductance values with tunability. This transconductor architecture makes it possible to realise a fully differential filter without the need for explicit common-mode feedback circuit. The filter has two tuning schemes, a resistor-based tuning (Rtuning) and a switched transconductor-based tuning (D-tuning). With R-tuning, the bandwidth is adjustable between 1 and 70 Hz and with D-tuning, the tuning range is 30 mHz–100 Hz. The filter has been designed in united microelectronics corporation (UMC) 0.18 µm complementary metal–oxide–semiconductor process. In terms of figure-of-merit, the proposed filter is found to be on par with the filters reported in the literature. © The Institution of Engineering and Technology 2018Item 1.8 V, 25.9 nW, 91.86 dB dynamic range second-order lowpass filter tunable in the range 4-100 Hz(Institution of Engineering and Technology kvukmirovic@theiet.org, 2019) Reddy, J.R.M.K.; Laxminidhi, T.A second-order lowpass Butterworth filter with tunable bandwidth capable of offering a dynamic range of 91.86 dB operating on a supply voltage of 1.8 V is presented. The proposed filter is based on a sub-threshold source follower. The transistor bias currents are switched to enable the bandwidth tuning in the range 4-100 Hz. A proportional to absolute temperature (PTAT) current reference circuit helps to keep the bandwidth intact across process, voltage and temperature variations. The filter, designed in 0.18 ?m standard CMOS process, consumes 25.9 nW making it a potential candidate for portable biomedical applications. © The Institution of Engineering and Technology 2019.Item Numerical study on temperature distribution during magnetic hyperthermia of different tumor tissues(Elsevier B.V., 2024) Ahammed, M.; Yadav, A.; Laxminidhi, T.In recent years, nanotechnology has made an invasion in biomedical applications which has gained much more attention because of its high efficiency and low side effects. One such application is magnetic hyperthermia (MHT) where magnetic nanoparticles (MNPs) are used to generate heat to kill the cancerous tissues over an alternating magnetic field. The heat generated by the nanoparticles is caused by hysteresis and Neel and Brownian relaxation. In this paper, a finite element method-based numerical modelling with the help of COMSOL is used to obtain temperature distribution on different tumor tissues (liver, lungs, and kidney) embedded with nanoparticles during magnetic hyperthermia by varying different magnetic field strengths (4000–6000 A/m), different frequencies (100–500 kHz) and different volume fractions of nanoparticles (0.1––0.5 %). Results show that at 500 kHz frequency, the temperature at the centre of the tumor is elevated marginally by 8 %, 4 %, and 2 % for the lungs, liver, and kidney respectively. Similarly, at 6000 A/m magnetic field strength, the temperature at the given point of tumor enhances moderately by 25 %, 14 %, and 8 % in the case of lungs, liver, and kidney respectively. The temperature at the same location increases majorly by 81 %, 45 %, and 20 % for the case of lungs, liver, and kidney respectively at 0.5 % volume fraction of nanoparticles. In the study, the effect of the volume fraction of nanoparticles on temperature rise is found to be more significant compared to other cases. The heat transfer rate is maximum in the lungs followed by the liver and kidney respectively. © 2024 Elsevier B.V.