Electrical Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

In this work, we build circuit models to understand the physics of electro-thermal instability and associated thermal runway in advanced ESD protection devices under filamentation. The circuit building methodology takes into account, the instability arising out of inhomogeneous triggering of 2 − D planar bipolar and looks into inherent instability causing the 3 − D phenomenon. Subsequently, the electro-thermal coupling is analyzed to get SPICE model, as we develop a physics based methodology to comprehend the 3 − D localization in the device. Furthermore, we understand the instability through appropriate modeling of localization behavior using area factor (α) and related electro-thermal circuit models. © 2017 Elsevier Ltd

World University root node

(SoE) School of Engineering

Microelectronics Reliability

SPICE level implementation of physics of filamentation in ESD protection devices

The present work focusses on the design and simulation of a thin film bulk acoustic resonator (TFBAR) and a polyimide based TFBAR (PI-TFBAR) and compares the radio frequency (RF) bandpass filter response designed from these resonators. The Polyimide layer in the PI-TFBAR acts as an acoustic wave reflector along with providing mechanical strength to the device. The designed third order bandpass filter has a ladder topology. The insertion loss of the TFBAR filter is 1.69 dB and the return loss is 39.60 dB whereas the insertion loss and return loss are 1.71 and 23.7 dB respectively for the PI-TFBAR filter. The bandwidth of the TFBAR filter is 68.0 MHz and for PI-TFBAR it is 25 MHz. The proposed filter designs, with further optimization, may have application in the 2.6 GHz band, which has been identified by the International Telecommunication Union as a global band for International Mobile Telecommunications and is one of the core bands of LTE-Advanced technology. © 2017, Springer-Verlag Berlin Heidelberg.

Microsystem Technologies

A comparative study on the design and simulation of TFBAR and polyimide-TFBAR based RF bandpass filters

Photoconductive Antenna (PCA) is considered to be simple and compact source for the terahertz (THz) generation. PCA is a common device to generate THz signals. It uses optical-to-electrical conversion to generate the THz radiation. However, the major problem with PCA is the lower efficiency, which is below 1%. The efficiency of PCA systems depends on the current pulse generated by the photo-carriers through the ultrashort laser pulse excitation. In PCA, high efficiency can be achieved by generating a high amplitude current pulse. In this communication a 2D simulation study of current pulse formation is analyzed in the PCA. Also, the effect of different parameters such as input laser power, applied DC bias voltage, antenna and semiconductor material on current pulse generation has been studied to understand the behavior of PCA. The aim of this communication is to analyze the effect of different parameters at low laser power where the screening effect can be neglected. This work is expected to provide better understanding of the mechanism of THz generation and in deciding optimum parameters for maximizing Optical-to-THz conversion efficiency of PCA. © 2015 IEEE.

2015 6th International Conference on Computers and Devices for Communication, CODEC 2015

A parametric study of photo carrier generation in Photoconductive Antenna

Photoconductive antenna (PCA), due to its simple and compact structure, is emerging in recent times as a popular device for generation of Terahertz (THz) frequencies. The working of PCA is based on the optical-to-electrical power conversion technique. The main advantage of the PCA is that it can be used both as a source as well as a detector with little changes in the operating mechanism. In literature, several experimental, simulation and theoretical studied are available for PCA operating as a source. However, very few experimental and simulation studies are available to analyze the performance of PCA as a receiver. In this communication, an effort has been made to analyze the performance of a PCA as a receiver by modeling an equivalent electrical circuit of it, which is based on the physics involved in its operation. © 2017 IEEE.

Proceedings of 2017 International Conference on Innovations in Electronics, Signal Processing and Communication, IESC 2017

Equivalent electrical circuit model of Terahertz photoconductive antenna receiver in a pulsed system

This study investigates the diagnostic sensitivity of gamma/beta and alpha/gamma ratios in discriminating dementia patients from healthy subjects. Our analysis uses EEG based Multivariate Fourier Decomposition method to extract the features of brain rhythms (alpha, gamma and beta) and their respective ratios for characterization. These features are analyzed using correlation in the sub-band of the envelope. Based on the results of this study, we propose that features gamma/beta and alpha/gamma ratios can be further analyzed using an extension of this method to fully evaluate their potential in the characterization of dementia. © 2016 IEEE.

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Fourier decomposition method based descriptor of EEG signals to identify dementia

In this paper, a complete transmitter has been designed using low-voltage differential signaling (LVDS) technology. It is a new analog technology based on the serial I/O interface data communications. The complete transmitter circuit consists of driver, cascode current mirror circuit, pseudo random binary sequence (PRBS), and electrostatic discharge (ESD) pad. Here, transmitter is designed initially, and its biasing has been done using cascode current mirror. The layout parameter variation approach has been used to design ESD protection circuit for transmitter. An effort was made to reduce the parasitic capacitance and parasitic resistance. It helps to improve the performance of transmitter and reducing electrostatic discharge issues. The complete system has been designed using 0.18 μm CMOS technology at 1.8 V. The data rate of 2 Gbps and power consumption of 6.3 mW has been achieved using Cadence virtuoso PDK of Silatera Malaysia. © 2016 IEEE.

Proceedings - 2016 6th International Symposium on Embedded Computing and System Design, ISED 2016

A methodology for designing LVDS interface system

In this paper, a 2-D analytical model for surface potential and threshold voltage of novel vertical super-thin body (VSTB) FET has been derived by solving 2-D Poisson equation. The analytical surface potential expression for gate-side surface and sidewall side surface has been modeled using parabolic surface potential approximation. The threshold voltage model for the VSTB FET has been derived by applying strong inversion criterion at the surface potential minimum value. The threshold voltage model for the VSTB FET has been analyzed by varying the body thickness, oxide thickness, and channel doping concentrations. The drain-induced barrier lowering and threshold voltage roll-off parameters are also extracted and analyzed for different body thicknesses. The models for surface potential and threshold voltage have been compared with the results obtained from the 2-D numerical device simulator and a very good agreement between the two has been observed. © 2017 IEEE.

IEEE Transactions on Electron Devices

2-D Analytical Modeling of Surface Potential and Threshold Voltage for Vertical Super-Thin Body FET

In this paper, an efficient implementation of the concurrent decision feedback equalizer (DFE) is carried out using offset binary coding (OBC) based on distributed arithmetic (DA). The concurrent decision feedback equalizer is employed in multi-gigabit systems which uses the principle of parallelization. However, the hardware complexity of adders and multipliers rises quadratically with parallelization factor. In our proposed technique, we have used look-up table (LUT) and shift-accumulate block as per DA requirement. In order to reduce the access time of LUT, we employed OBC scheme which therefore improves the speed of filtering operation. Moreover, it also reduces the chip area for LUT based filter design. Furthermore, our design provides significant reduction of hardware complexities in spite of slight increase in address decoding logic of OBC combinations while LUT complexity grows linearly. By doing so, the concurrent nature of look-ahead DFE is unaltered and can still be used for multi-gigabit applications. We have estimated hardware complexity and critical path of our design and compared with best existing schemes. Synthesis is performed in UMC 180 nm CMOS technology using cadence RTL compiler for the feedback filter length N = 4, 6 and 8. The proposed structure of concurrent look-ahead DFE is found to have low area in comparison to other schemes for any length of the feedback filter. © 2016 IEEE.

2016 20th International Symposium on VLSI Design and Test, VDAT 2016

Efficient implementation of concurrent lookahead decision feedback equalizer using offset binary coding

In this work two isomeric copolymers of benzodithiophene and BODIPY have been designed and synthesized. Structural isomeric polymers were designed such that one of the polymers exhibits more planar architecture, which would help in understanding the effect of structural isomerism and planarity in the polymer backbone on charge carrier mobility. Structural differences in of both these structures were also studied using DFT and TDDFT calculations. © 2017 IEEE.

2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017

Effect of structural isomerism on charge transport in copolymer of BODIPY and benzodithiophene

A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at -5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3. © 2017 Viswanathan et al.; licensee Beilstein-Institut.