Scanning the Issue

The current issue of the IETE Journal of Research (Vol.66, No.4, July-Aug, 2020) contains 14 articles. These articles present ongoing research and developments taking place in the broad areas of Control Systems, Communication Engineering, Microelectronics, Biomedical Engineering and Power Systems.

The first paper in the issue “Adaptive PID Controller with P&O MPPT Algorithm for Photovoltaic System,” presents a method for extracting maximum power from photovoltaic system based on perturb and observe (P&O) adaptive PID controller and maximum power point tracking (MPPT) algorithm. The controller gains are calculated for different operating conditions without the use of additional sensors. A linear relation between the gains and operating conditions is adaptively changed as required. The performance is evaluated and compared in simulations and experimental studies are reported in the paper.

The second paper on “Analysis on the Grounding Architecture of a Technology Demonstrator Vehicle,” presents the study of the grounding architecture of satellite launch vehicles through simulation models. The paper discusses various grounding issues in the testing of a technology demonstrator vehicle and how these are mitigated.

The next paper on “Fabrication of Tin Oxide Nanoparticles for CO₂ Gas Sensing Layer” presents the process for fabrication of tin-oxide based nanoparticles using ultrasound probe. The morphology of the synthesized nanoparticles has been studied and SEM and X-ray diffraction patterns are reported. The paper further discusses its use in the detection of carbon dioxide gas at room temperature and its detection sensitivity is presented.

The following paper titled “Generalized Characteristic Ratios: Definition, Assignment, and Application,” presents definition of Generalized Characteristic Ratios to measure the characteristics of the transient response of minimum-phase linear time-invariant systems. The ratios are generalized from previous all-pole system cases to include pole-zero system transfer functions. The usefulness of these ratios is in suitably designing zeros of system transfer functions. Numerical simulation studies are presented to demonstrate application and justify the usefulness of the definitions.

The paper on “MOS Amplifier Design Methodology for Optimum Performance,” presents a design methodology of MOS cascode amplifier by optimizing design variables on a polytope-type performance measure surface. The optimization problem with variable constraints is presented as a nonlinear programming task and the performance trade-offs in terms of small signal gain, unity gain frequency and gain bandwidth product are discussed and inferences about the design are drawn.

In “Multi-Resolution-Analysis-based Line-to-Ground Fault Detection in VSC-Based HVDC System,” the authors consider the problem of identifying single line to ground fault in a voltage source controller based high voltage DC link. This is done using multi-resolution analysis with discrete wavelet transform. The paper reports the algorithm performance of assessment of fault locations based on case studies in software based on field data. Inferences about the algorithm and its performance are made and discussed.

The following paper on “Parallel Inductor Multilevel Current Source Inverter for Input Ripple Current Reduction in PEM Fuel Cell Applications,” presents the design of a five-level current source inverter with reduced second harmonic current ripple. The features of energy recovery scheme that balances inductor currents, reduced size of input DC link inductor and reduced circuit structure for reliable power conditioning are discussed in the paper.

The next paper on “Sleep Apnea Diagnosis by DWT-Based Kurtosis, Radar and Histogram Analysis of Electrocardiogram,” presents algorithm for sleep apnea assessment using discrete wavelet transform based features derived from the electrocardiogram. Details of the algorithm are presented. The performance outcome in terms of distinguishing normal persons from apnea patients are presented and discussed.

In the next paper “Sub-1 V, 5.5 ppm/°C, High PSRR all CMOS Bandgap Voltage Reference,” the authors present the design of a voltage reference circuit with high power supply rejection ratio and supply voltage ranging from 0.9 V to 4 V. A voltage reference unit independent of process, voltage and temperature variations is used in wide variety of circuits. The design is discussed in detail and the realization in 0.18 µm CMOS technology is described in terms of performance parameters.

The following paper “TDOA and RSSD Based Hybrid Passive Source Localization with Unknown Transmit Power” presents a method for passive source localization using combination of time difference of arrival and received signal strength difference. A maximum likelihood estimator with analytical solution and bound of performance are derived assuming models for signal, propagation and noise. The analytical and simulation performance are compared and inferences on performance are discussed.

The paper on “Threshold Voltage Modelling of Linearly Graded Binary Metal Alloy Gate Electrode with DP MOSFET,” presents the study of threshold voltage model for linearly graded binary metal alloy gate electrode with dielectric pocket MOSFET. The model is based on solving 2D Poisson’s equation wherein surface potential, threshold voltage, drain current, transconductance and drain conductance expressions are derived. The analytical results are compared with results obtained from a standard simulator to draw conclusions about the model.

The paper “Unknown Inputs Observer-Based Output Feedback Predictive Controller for an Activated Sludge Process,” presents the study of the control problem of an activated sludge process having unobservable states and unknown inputs. A multi-input multi-output nonlinear predictive controller is investigated and methods to overcome the constraints of the system states and inputs are presented in the paper. The performance of the feedback predictive control system is investigated using simulation studies and results are presented to support the efficacy of the designed controller.

The next paper on “Unsupervised Event Detection Using Self-learning based Max-margin Clustering: Analysis on Streaming Tweets,” studies the problem of clustering of tweets from streaming media using large repository of data for self-learning. An unsupervised processing technique of self-learning max-margin clustering is investigated due to the unstructured nature of tweet data for meaningful information retrieval. The proposed technique is compared with other techniques based on precision and other scores and inferences on the efficacy of the technique are drawn.

Finally, the paper “Wide Bandgap Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering at Room Temperature,” describes the preparation of zinc oxide thin films using room temperature RF magnetron sputtering deposition on glass substrate. The applications of the technique include solar cells, surface acoustic wave devices and preparation of other thin file devices on flexible substrate. The characteristics of the deposition technique such as measured surface roughness, sample height, current-voltage graphs and transmittance spectra obtained from prepared samples are presented in the paper.

Editor-in-Chief

Shiban K Koul is currently an Emeritus Professor at the Indian Institute of Technology, Delhi. He served as Deputy Director (Strategy and Planning) at IIT Delhi from 2012–2016 and Mentor Deputy Director (Strategy & Planning, International Affairs) at IIT Jammu from 2018–2020. He also served as the Chairman of Astra Microwave Products Limited, Hyderabad from 2009–2019 and Dr R.P. Shenoy Astra Microwave Chair Professor at IIT Delhi from 2014–2019. His research interests include: RF MEMS, High Frequency Wireless Communication, Microwave Engineering, Microwave Passive and Active Circuits, Device Modeling, Millimeter Wave IC Design and Reconfigurable Microwave Circuits including Antennas. Completed 38 major sponsored projects, 52 consultancy projects and 60 technology development projects. He has authored 455 Papers, 11 state-of-the art Books and 3 Book Chapters. He holds 11 patents and 6 copyrights. He is a Life Fellow of IEEE and Fellow of INAE and IETE. He is the Chief Editor of IETE Journal of Research, Associate Editor of the International Journal of Microwave and Wireless Technologies, Cambridge University Press. He served as a Distinguished Microwave Lecturer of IEEE MTT-S for the period 2012–2014.

Recipient of numerous awards including IEEE MTT Society Distinguished Educator Award (2014); Teaching Excellence Award (2012) from IIT Delhi; Indian National Science Academy (INSA) Young Scientist Award (1986); Top Invention Award (1991) of the National Research Development Council for his contributions to the indigenous development of ferrite phase shifter technology; VASVIK Award (1994) for the development of Ka-band components and phase shifters; Ram Lal Wadhwa Gold Medal (1995) from the Institution of Electronics and Communication Engineers (IETE); Academic Excellence Award (1998) from Indian Government for his pioneering contributions to phase control modules for Rajendra Radar, Shri Om Prakash Bhasin Award (2009) in the field of Electronics and Information Technology, VASVIK Award (2012) for the contributions made to the area of Information, Communication Technology (ICT) and M N Saha Memorial Award (2013) from IETE. E-mail: [email protected]