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

This work presents a circularly polarized Fabry- Perot cavity antenna (FPCA) using a new uniplanar electro- magnetic bandgap (EBG) superstrate. Proposed EBG poses a frequency bandgap in the sub-6 GHz frequency range from 3.07-4 GHz. Unit cell has overall dimension of 0.071 λ0 × 0.071 λ0 × 0.018 λ0, where λ0 is the free space wavelength at center frequency of 3.53 GHz. A 7 × 7 EBG lattice is used as partially reflective surface (PRS) over a metamaterial based circularly polarized (CP) antenna to improve the directivity. Peak gain of the primary CP antenna is 7.51 dBic at 3.66 GHz and that of the EBG superstrate loaded FPCA is 9.67 dBic. © 2020 IEEE.

Department of Electrical Engineering

World University root node

Proceedings of the 2020 International Symposium on Antennas and Propagation, APSYM 2020

EBG Superstrate Loaded Circularly Polarized Fabry-Perot Cavity Antenna at Sub-6 GHz for Satellite and 5G Cellular Communications

This paper presents a wide band six port network (SPN) with two input ports and four out ports. The designed network consists of conventional wideband Lange couplers and a Wilkinson power divider having features of out of band harmonic suppression over a wide frequency. Operation band of the SPN extends from 2.3 - 4.0 GHz covering IEEE 802.11 WLAN band at 2.4 GHz and sub-6 GHz band from 3.3 - 3.8 GHz for 5G application. A good matching at the input ports are achieved with return loss of better than 20 dB for the entire frequency range with minimum isolation between the ports is 12 dB. At frequency 3.5 GHz the output powers at the four ports are -5.56 dB, -5.47 dB, -7.07 dB, -7.16 dB with input at port-1 and the powers are -6.05 dB, -7.8 dB, -5.02 dB, -6.56 dB with input at port-2. Differential phase between two adjacent output ports are ± 90 degree. © 2020 IEEE.

IEMTRONICS 2020 - International IOT, Electronics and Mechatronics Conference, Proceedings

Compact six-port network using lange coupler for sub-6 GHz fifth generation communication

A wide-width clamped-clamped beam (CC-beam) resonator and a filter realized using mechanically-coupled resonator tanks have been extensively characterized to attain mixler (i.e., mixer-filter) functionality for a chip-scale frequency translation. Such a resonator has been driven into the nonlinear regime to explore its effect on the mixler operation as well as to obtain the best phase noise performance using the phase-feedback method. The proposed electrostatically transduced mixler operates by utilizing the local oscillator (LO) signal generated from the resonator itself, thus eliminating the need of a function generator or an external quartz crystal oscillator. This technique implemented with all the components on the same silicon substrate shows great potential for miniaturization in wireless communication while achieving 14.4 dB overall mixler loss. © 2019 Elsevier B.V.

Sensors and Actuators, A: Physical

A chip-scale frequency down-conversion realized by MEMS-based filter and local oscillator

We propose a Simulation Program with Integrated Circuit Emphasis (SPICE)-based multiphysics framework to model ferroelectric negative-capacitance-electrostatic microelectromechanical systems (MEMS) hybrid actuators. Our approach couples the nonlinear dynamics of both the ferroelectric capacitor and the MEMS actuator. Using this framework, we examine the dynamic response and the energy consumed during pull-in switching of the hybrid actuator. We predict a significant reduction in the dynamic pull-in and pull-out voltages and the energy consumed by the hybrid actuator compared with the standalone MEMS actuator. We also predict that the pull-in time of the hybrid actuator is, however, larger than that of the standalone actuator. Nevertheless, we show that one can tradeoff a small part of the reduction in actuation voltage to achieve identical pull-in times in the hybrid and standalone MEMS actuators while still consuming substantially lower energy in the former compared with the latter. Our analysis approach is compatible with standard circuit simulators and is, hence, suitable for analysis and evaluation of various heterogeneous systems consisting of hybrid MEMS actuators and other electronic devices. © 1963-2012 IEEE.

Fulltext

IEEE Transactions on Electron Devices

SPICE-Based Multiphysics Model to Analyze the Dynamics of Ferroelectric Negative-Capacitance-Electrostatic MEMS Hybrid Actuators

This paper proposes a new space vector based pulse width modulation (PWM) technique to operate a five phase induction machine fed by two level inverter in the overmodulation region with significantly low harmonic distortion and switching loss. The proposed technique is simulated in MATLAB - SIMULINK and the results are compared with the existing PWM techniques. A comparative study of the performance of the five phase drive using stator flux ripple concept with the proposed PWM technique is presented in the over-modulation region. The simulation results are experimentally validated using TMS320F28379D micro-controller platform with a custom made five phase drive system. It is found that in the over-modulation region, the proposed PWM technique results in considerably low RMS current ripple and switching power loss as compared to those corresponding to the conventional PWM techniques. © 2020 IEEE.

9th IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2020

Space vector modulation technique with improved harmonic performance for a five phase induction motor drive in the over-modulation region

The design of apodization and windowing functions forms the predominant part of the beamforming process in ultrasound imaging. However, the detailed analysis of apodization in the case of beamforming for flow imaging is very limited in the literature. This paper introduces the concept of dual apodization technique in vector triangulation for ultrasound-based vector flow imaging. The approach utilizes the idea of multiple apodization to induce a steering effect at receive along with sidelobe suppression for the delay compensated radio-frequency (RF) signals. The method is investigated using extensive simulations for transverse flows with different flow profiles at different velocities, which shows an improvement in resolution and better clutter suppression. The proposed approach is further analyzed using various conventional and data adaptive apodization techniques for a gradient flow profile. The error variance in velocity magnitude estimate is as low as 5.0251\times 10^{-4}\ [m/s]^{2} and the mean angle error is +0.7358° using Hanning-Gaussian apodization for a transverse gradient flow with a peak velocity of 0.25 m/s. © 2020 IEEE.

Proceedings - International Symposium on Biomedical Imaging

Directional Beam Focusing Based Dual Apodization Approach for Improved Vector Flow Imaging

Ultrasound (US) imaging systems typically employ a single beamforming scheme which is the delay and sum (DAS) beamforming due to its reduced complexity. However, DAS results in images with limited resolution and contrast. The limitations of DAS have been overcome by, delay multiply and sum (DMAS) beamforming, making it especially preferable in cases where finer image details are required in larger depth of scans for an accurate diagnosis. But, DMAS is confined to transducer frequencies where the generated harmonics also fall in the processable frequency range of the US system. However, if US systems could provide the flexibility to reconfigure beamforming considering the restrictions of each beamforming scheme, it is possible to select the best beamforming according to the clinical requirement and system constraints. This work is a fundamental step towards enabling reconfigurable beamforming for on-the-fly selection among the DAS and DMAS beamforming schemes, with low reconfiguration overhead, specifically for each imaging scenario to aid better diagnosis. Two novel architectures are proposed, that reconfigures between DAS and DMAS beamforming as a function of transducer's center frequency with minimum additional computational overhead. The implementation results of the proposed architectures on xc7z010clg400-1 FPGA are reported. The possibilities of pixel-level beamforming reconfigurability, where the different tissue regions are beamformed with either DAS or DMAS are also shown through simulations. © 2007-2012 IEEE.

IEEE Transactions on Biomedical Circuits and Systems

Towards A Pixel-Level Reconfigurable Digital Beamforming Core for Ultrasound Imaging

This letter examines a state estimation with event-based transmissions for a linear discrete-time system when multiplicative noise affects the measurements while the additive noises of process and measurements of the sensor are correlated with each other. A general event-based technique is applied to produce the measurements at event-triggering instants and the sum of Gaussians approach is used at remote estimator to address the computation of state estimate when measurements are unavailable. The two-step predicted probability density function with Gaussian assumption is used to derive the recursive equations for the state estimate and its covariance matrix when the correlation between additive noises is at the same epoch. The results proposed are validated by a numerical example. © 2017 IEEE.

IEEE Control Systems Letters

Event-based state estimation with multiplicative measurement noise and correlated additive noises

Functional splitting and packetized fronthaul (FH) are two approaches to realize cloud radio access networks in a cost-effective manner. In the former, some baseband functionalities are offloaded to remote radio units (RRUs) instead of centralizing all of them at a baseband unit pool. This reduces the capacity and latency requirements on FH when massive multiple-input-massive-output RRUs are used. The latter approach aims to use the ubiquitous Ethernet networks for FH. However, this leads to random packet delays due to queuing at switching/aggregating gateways. In this letter, we present a novel analytical framework to characterize the distribution of queuing delays at an aggregation gateway in the uplink. This framework incorporates random user activity, the uplink spectral efficiencies of users, the slotted nature of uplink transmissions, and FH capacity. We study the impact of packet arrival rates, average packet sizes, and FH capacity on queue length and queuing delay distributions. We show that significant statistical multiplexing gains are possible by aggregating traffic from multiple RRUs. © 1997-2012 IEEE.

IEEE Communications Letters

Uplink Latency in Massive MIMO-Based C-RAN with Intra-PHY Functional Split

The cascaded H-bridge (CHB) multilevel converter has been used in various applications, such as the STATCOMs and solid-state transformers. Due to its modular structure, fault tolerance can be incorporated in the CHB multilevel converter. In this article, a model predictive control (MPC)-based fault detection and localization (FDL) scheme is proposed for the CHB multilevel converter that utilizes the already-installed ac current measurement and does not require additional sensors. The proposed FDL scheme can detect single or multiple open-circuit switch faults in the CHB multilevel converter by comparing the predicted states of the MPC controller with the actual measured states. The detected fault(s) is(are) further localized through a fault localization matrix which narrows down the faulty switch using historical fault data. The proposed scheme is shown to complete the FDL process for both single or multiple open-switch faults within a fundamental cycle period, even during low-load conditions. It has also been shown that the proposed scheme is immune to system dynamics such as load and voltage variations, and has been validated experimentally for various open-circuit fault scenarios. © 1986-2012 IEEE.