Department of Electrical Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Perovskite-silicon tandem solar cells show enhanced efficiencies due to the broader absorption of the solar spectrum. Luminescent coupling is generally observed in multi-junction solar cells, where a fraction of emitted photons from the higher bandgap optically active layer are absorbed by the lower bandgap optically active layer and converted to photocurrent. Therefore, it is necessary to model the current-voltage characteristics of perovskite-silicon tandem solar cells to understand the impact of luminescent coupling on the performance of these devices. In our work, we have a semi-analytical framework to obtain the current-voltage characteristics of multijunction perovskite-silicon tandem solar cell, accounting for the presence and absence of luminescent coupling. We have compared the calculated current-voltage characteristics with experimentally measured data reported in literature. © 2022 IEEE.

World University root node

Proceedings of the IEEE Conference on Nanotechnology

Analysis of perovskite-silicon tandem solar cells using a semi-analytical model

This paper investigates the potential impact of inverter based resources (IBRs) on the well known negative sequence impedance (NSI) element (32Q) based directional relaying scheme. CIGRE-14 bus test system with IBRs is modeled on PSCAD environment. Both the inverter control along with the directional relay scheme are modeled in detail. The test results indicate that the conventional 32Q element will find its limitations in the presence of IBRs. Absence of significant level of negative sequence fault current along with changed angular relationship between negative sequence voltage and current are found out to be the primary causes behind such relay mal-operations. Further, the impact of connections of interconnecting transformer are also analyzed. © 2022 IEEE.

2022 22nd National Power Systems Conference, NPSC 2022

Revisiting Performance of Negative Sequence Directional Relay (32Q) in the Presence of Inverter Based Resources

The soft-switched modulation techniques presented in recent literature for single-phase half-bridge matrix-based dual-active-bridge (MB-DAB) ac-dc converter either suffers from incomplete soft-switching or computationally and memory expensive numerical technique requirement. An analytical expression-based modulation scheme for half-bridge MB-DAB, which is directly implementable on a microprocessor, is presented in this article that is capable of achieving near full-cycle ZVS turn-on of all MOSFETs and unity power-factor (UPF) operation. The theoretical derivations, working principles, and loss modeling are presented through suitable formulations. A 2.2-kW(pk) hardware prototype is fabricated, for which a PSIM simulation model is also developed using the MOSFET manufacturer's SPICE models and other components' datasheet parameters. The experimental results demonstrate near full-cycle ZVS turn-on over a wide load range (12\%-100\%), UPF operation, and 96.6\% conversion efficiency at full-load in agreement with the simulation results, which validate the proposed modulation approach.

IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS

Analytical Expression-Based Modulation for Soft-Switched Matrix-Based Dual-Active-Bridge (S2MB-DAB) Single-Phase AC-DC Converter

New uniplanar electromagnetic bandgap (EBG) element is designed in this work for the superstrate of highly directive planar antenna and microwave filter design. The layout of the EBG is conceived of four arms spiral resonators (FASRs) and four corner square patches as a part of interdigital capacitor (IDC). The unit cell has dimension of only 3 mm, and the structure is engineered on a grounded dielectric substrate Taconic TLC-32 of thickness 0.79 mm. The designed EBG exhibits a wide bandgap property between the frequencies of 9.6-12.48 GHz ( 26.1 %). This work focuses on two different applications of the EBG - one as a superstrate of the microstrip antenna and the second as EBG loaded microstrip filter. The EBG loaded patch shows gain enhancement of 7.1 dB and bandwidth (BW) improvement of 330 MHz as compared to the reference antenna. A novel EBG based wideband filter is proposed for the C-band application. The passband BW of the filter covers the frequencies of 4.76-7.29 GHz (42 %) having insertion loss (IL) in the structure is below 1.2 dB over the operating range. © 2022 IEEE.

INDICON 2022 - 2022 IEEE 19th India Council International Conference

Novel Uniplanar Electromagnetic Bandgap Structure for High Gain Antenna and Filter Designs

A single-layered broadband linear-linear reflective type polarization converter is proposed in this article. The top patch comprises a 45° tilted novel H-shaped dipole printed on a 33.5μm thin polyamide substrate grounded on the other side. The design exhibits a minimum 90% Polarization Conversion Ratio (PCR) over 0.64 THz (0.67-1.31 THz) bandwidth and 64.65% Fractional Bandwidth (FBW). The motivation lies in this converter's design exhibiting near-unity conversion at 1 THz. The structure shows a stable broadband response up to 40° for both Transverse Electric (TE) and Transverse Magnetic (TM) modes with a bandwidth reduction of up to 30% without compromising the cell's performance. The proposed unit cell is compact with the structural periodicity of 0.188λL and thickness 0.075λL, where λL is the free-space wavelength corresponding to the lowest frequency of the broadband. The authors strongly believe that the proposed design possesses features like compactness angular stability, making this design suitable for applications where the reflective type linear-cross polarization conversion is the primary need. © 2022 IEEE.

2022 IEEE Wireless Antenna and Microwave Symposium, WAMS 2022

Novel Modified H-shaped Linear-Cross Reflective Type Polarization Converter at THz Regime

This work presents a flat-gain antipodal Vivaldi antenna (AVA) for ultra-wideband (UWB) microwave imaging applications. The proposed antenna demonstrates measured and simulated impedance bandwidth from 2.3 GHz to 20 GHz with a flat gain over the band, with minimum gain variation of 2.9 dBi. The antenna is tested initially for its practical utility by measuring its specific absorption rate (SAR) value. The SAR value is observed in the simulator by modeling a realistic homogeneous as well as a heterogeneous breast phantom. The SAR value obtained complies with both American and European standards when averaged over 1 g as well as 10 g of tissue. The designed antenna is further utilized to detect multiple tumors in a realistic homogeneous and heterogeneous breast phantoms developed in the laboratory environment. The widely popular delay and sum (DAS) algorithm is utilized to reconstruct the tumor images. The imaging is done outside the anechoic chamber with an in-house monostatic microwave imaging setup just to make it more convincing with real-world dynamic scenario. The homogeneous phantom with four embedded tumors each of radius 4 mm and the heterogeneous phantom with two tumors, one of radius 3.5 mm and another of radius 5 mm are imaged in this work. The imaging results demonstrate that tumors of different sizes can be detected accurately in the case of both homogeneous and heterogeneous breast phantoms. AVA with an oil paper layer for bandwidth enhancement as well for achieving flat-gain response is first of its kind to be reported in this work Also, the proposed work utilizes different phantoms for imaging several tumors of differing sizes, which has not before been described. © 2022 Wiley Periodicals LLC.

International Journal of RF and Microwave Computer-Aided Engineering

Non-invasive breast tumor detection with antipodal Vivaldi antenna using monostatic approach

This research introduces a metamaterial-based compact radiator for breast tumor spotting. The structure is built on an FR4 material with a ϵr = 4.4 and thickness 1.6 mm. On the hind side of the developed structure, a Frequency selective surface (FSS) is attached for gain improvement. The suggested device has a broad bandwidth (S11 > 10 dB) in the sweep from 2.9 - 36 GHz and has maximum gain of 8.5 dBi at 14 GHz. To test the impact of radiation on the human breast, the developed radiator is subjected to a Specific Absorption Rate (SAR) study using a hemispherical breast phantom modelled in the CST Microwave studio EM Solver. © 2022 IEEE.

Metamerial-Based Monopole Antenna for Breast Cancer Detection

In this work, a star shaped patch with an outer ring structure is designed in the simulator for microwave head imaging applications. The designed antenna operatres from 1.47 GHz to 4.7 GHz with an impedance matching of greater than 10 dB. The antenna attains a peak gain of 3.8 dBi at 4.3 GHz. The Specific Absorption rate (SAR) of the designed antenna is checked to evaluate the effect of the antenna on the human head. This is done by separately designing a 7 layered head phantom. The antenna is also utilized to image brain tumor by introducing a cancerous tumor inside the brain phatom for imaging. Finally, brain tumor is obtained successfully after imaging using widely popular Delay and Sum (DAS) algorithm. © 2022 IEEE.

2022 IEEE Microwaves, Antennas, and Propagation Conference, MAPCON 2022

Brain Tumor Detection with Compact Monopole Antennas using Microwave Medical Imaging

This article presents single-layer conformal high angle stable miniaturized triband bandstop frequency selective surface (FSS) for microwave shielding. This new FSS is supported on an ultrathin dielectric substrate and has stable response with change in polarization and incidence angle. Via-less convoluted geometry is adopted in the unit cell design to increase spatial efficiency with a unit cell size of 0.091 λL, where λL is the wavelength at lowest resonance. The proposed FSS exhibits three transmission zeros at 4, 6.95, 11.3 GHz with stopband bandwidth (BW) founds application for shielding the C/X band frequencies for satellite communication. A prototype of the proposed FSS is fabricated. The filter response is measured on normal and on curved surfaces. Simulated and measured transmission coefficients confirm the operating principle of the FSS. Unit cell periodicity of the triband FSS is further reduced by using two layers based 2.5-D geometry. The modified unit cell has a periodicity of 0.038 λL and exhibits stopband BWs center at 0.8, 1.4, and 2.36 GHz. © 1964-2012 IEEE.

IEEE Transactions on Electromagnetic Compatibility

Conformal Miniaturized Angular Stable Triband Frequency Selective Surface for EMI Shielding

This work demonstrates a novel linear-circular wideband transmission type polarization converter for K-and Ka-band applications. The unitcell comprises primarily two FSSs on both sides of a thin dielectric substrate. For a linear polarized wave incidence, the transmitted wave is circularly polarized with a minimum 3 dB Axial Ratio (AR) from 19.08-37.27 GHz with a relative bandwidth of 64.56% and near 0 dB AR at two frequencies, 24.4 GHz and 34.8 GHz. The response is angular stable, almost up to 45° for different oblique incidences under Transverse Electric (TE) and Transverse Magnetic (TM) modes. Electric field patterns are also investigated to visualize the circular polarization rotation sense. The unitcell is compact with a structural periodicity of 0.102?L×0.134?L and thickness of 0.051?L, where ?L is the free-space wavelength corresponding to the lowest operating frequency. In addition, this design offers a bandwidth tunability feature by adjusting the stub's length at the back FSS. Since the design is miniaturized with 0.697(?3L/ 1000) volume and wideband stable angular performance made this a potential candidate for real-time satellite applications. © 2022 The Institute of Electronics Information and Communication Engineers (IEICE) of Japan.