Electrical Engineering

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An acceptor-donor-acceptor (A-D-A) triad based on a BODIPY acceptor and a benzodithiophene donor exhibited dual fluorescence and pronounced fluorescence solvatochromism because of twisted intramolecular charge transfer (TICT) state formation. Furthermore, it showed a Stokes shift of ∼194 nm which is the highest known for any BODIPY compound with a readily tunable fluorescence and a high charge carrier mobility of 4.46 × 10-4 cm2 V-1 s-1. © 2018 The Royal Society of Chemistry.

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Organic and Biomolecular Chemistry

Dual emissive bodipy-benzodithiophene-bodipy TICT triad with a remarkable Stokes shift of 194 nm

This paper presents a novel approach to estimate the maximum power point (MPP) of a photovoltaic (PV) array. The MPP of the PV array is directly estimated from the current-voltage (I-V) curve by using Improved Bisection Method (IBM) under different irradiation and temperature conditions. The five parameters single diode model PV module parameters are estimated from the data sheet values given by the manufacturer under standard test condition (STC). The IBM is simple, fast and returns the MPP more accurately. The estimation of MPP of a PV array under different environmental conditions is presented by using MATLAB program. Also, a comparison of the proposed method with different existing methods has been presented for tracking of MPP of the PV array. It is observed that the estimated MPP of the module is nearly equal to the actual MPP values and thus the performance of the proposed method is more accurate. © 2018 IEEE.

ITEC Asia-Pacific 2018 - 2018 IEEE Transportation Electrification Conference and Expo, Asia-Pacific: E-Mobility: A Journey from Now and Beyond

Maximum Power Point Estimation of a PV Array by Using Improve Bisection Method

Analytical and simulation modeling of the terahertz photoconductive antennas

This paper presents a broadcasting antenna design operating at 2.4 GHz frequency. The proposed antenna is designed, simulated and fabricated on FR4 substrate of permittivity 4.1 and thickness 1.5 mm. The measured return loss is 17.5 dB at 2.4 GHz whereas the simulated return loss is 36.88 dB. Thus, the fabricated & simulated antenna are in good harmony. Also the cross polarization is less than -20 dB. This antenna can be used to broadcast on several type of wireless systems that we use in our day to day life like Amplitude modulation (AM), Frequency modulation (FM) radio, satellite telephony & Global Positioning System (GPS). © 2016 IEEE.

2016 IEEE International Conference on Recent Trends in Electronics, Information and Communication Technology, RTEICT 2016 - Proceedings

Slotted ground circular antenna for personal communication system (PCS) &amp; broadcasting

In recent years, thermal imaging has played an increasingly important role in the area of nondestructive testing for subsurface defects. The two predominantly used thermal imaging techniques arelock- in thermography and pulse thermography. Lock-in thermography is based on periodically heating a test-piece. The resultant periodic temperature variation resembles a wave and is known as a thermal wave. It's propagation is characterised by changes in phase and amplitude and this information generates the phase and amplitude thermal images. Pulse compression thermal imaging is a relatively new defect detection technique. Herein a thermal excitation within a band of frequencies is incident on the sample and processed with a reference signal to generate an output identical to that of a pulsed thermography experiments. A comparison between the two techniques for defect detectability is presented on a Carbon-Fibre Reinforced Polymer (CFRP) sample with machine blunt holes of varying depths. The experiments are conducted at different frequency range necessary to produce thermal diffusion lengths to cover the set of defect depths to be detected.

WCCM 2017 - 1st World Congress on Condition Monitoring 2017

Comparison of lock-in and pulse compression thermal imaging techniques for non-destructive defect detection

This study presents a robust technique to estimate the maximum power point (MPP) of a double-diode model (DDM) photovoltaic (PV) module. The MPP of the DDM PV module under different environmental conditions (DECs) are estimated by using the simple and computationally efficient Levenberg-Marquardt method. The variation of double diode PV module parameters with the change of temperature and irradiation is analysed. The MPP of the DDM PV array at non-standard test condition obtained from the proposed method is verified with the MPP obtained experimentally and by MATLAB simulation. A comparative study of MPP of a DDM PV module estimated from the proposed method with different existing methods is performed for different operating conditions. The maximum measurement error in power generation of a DDM PV module for different methods under DEC is presented which indicates better performance of the proposed method for the estimation of MPP of a DDM PV module. © The Institution of Engineering and Technology.

IET Power Electronics

Estimation of maximum power point of a double diode model photovoltaic module

In this paper a novel planar antenna is proposed for 5.2GHz band application. The area of designed antenna has been reduced by 52\% in comparison to a conventional rectangular microstrip patch antenna. The antenna has three vertical stripes and one horizontal stripe. The length and width of these stripes are varied to tune the antenna for a certain operating frequency. The antenna is fed by using a 50 ohm microstrip line connected at the center of horizontal stripe. The fabricated antenna has return loss of 22dB at 5.27GHz and impedance bandwidth of 120MHz. A parametric study has been carried out to analyze and to find the design sensitive parameters. © 2017 IEEE.

2017 International Symposium on Antennas and Propagation, ISAP 2017

Step shape antenna for MIMO applications

Magnetic resonance coupling (MRC) based wireless power transfer (WPT) system is recognized as an efficient and promising technology for safe, convenient and elegant charging solution for various electronic portable devices. MRC technology helps in transferring power wirelessly from transmitter to receiver over larger distances. However in such loosely coupled systems, low power transfer efficiency is the major issue in comparison to conventional wired charging systems. The paper presents detailed analysis of power transfer efficiency between two independent coils separated by distance of 15 cm. The analysis involves an effect of coil geometrical dimensions on power transfer efficiency and mutual inductance between transmitter (TX) and receiver coils (RX). In addition, the investigations are further extended to analyze the role of shielding and effect of shielding geometry on power transfer efficiency and mutual inductance between the two coils. © 2016 IEEE.

2016 IEEE 7th Power India International Conference, PIICON 2016

Effect of coil geometry and shielding on wireless power transfer system

A computational study of effect of solder geometric parameters on the stress generation in microelectronic circuits of Light Emitting Diodes is presented. The stress developed in the SAC (SnAgCu) solders is a function of the solder height used in the packaging. This parameter has restriction in usage due to geometrical constraints and hence it becomes a critical parameter in assessing the stress level in the packages. The plastic stresses generated in the viscoplastic SAC solders due to thermal loading are mostly responsible for the stress generation in the GaN LED layer. The residual or the post operational stress level in the GaN LEDs can be a critical parameter in understanding the light output from it. The performance may change due to the generation of defects, which is due to the residual stresses induced in the die. Hence, the residual stress level and its propagation from solder up to GaN LEDs is analyzed to reduce package stress which is presented in this work. The objective of this work is also to provide analysis related to packaging and reliability related issues on the basis of residual thermal stresses and to provide a parametric study on the basis of the interconnects used in it in order to enhance its stability as well as performance. © 2017 IEEE.

IEEE International Reliability Physics Symposium Proceedings

A simulation study on residual thermal stresses in high power GaN LEDs

In recent years, several experimental and simulation studies have been reported on the terahertz (THz) generation using a photoconductive antenna (PCA). The major problem with PCA is its low overall efficiency, which depends on several parameters related to a semiconductor material, an antenna geometry, and characteristics of the laser beam. To analyze the effect of different parameters on PCA efficiency, accurate circuit modeling, using physics undergoing in the device, is necessary. Although a few equivalent circuit models have been proposed in the literature, these models do not adequately capture the semiconductor physics in PCA. This paper presents an equivalent electrical circuit model of PCA incorporating basic semiconductor device physics. The proposed equivalent circuit model is validated using Sentaurus TCAD device level modeling tool as well as with the experimental results available in the literature. The results obtained from the proposed circuit model are in close agreement with the TCAD results as well as available experimental results. The proposed circuit model is expected to contribute towards future research efforts aimed at optimization of the performance of the PCA system. © 2017 Elsevier B.V.