Department of Electrical Engineering

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IIT Jodhpur

The application of a film bulk acoustic resonator (FBAR) as a gas sensor is presented here. Zinc Oxide is used as a piezoelectric (PZE) material for the resonator and a Bragg reflector is made of Molybdenum and Silicon dioxide in proposed Solidly Mounted FBAR. The structure offers a high quality factor of 1209 at the resonance and shows a coupling coefficient of 7.51% for the 0.7-μm-thick PZE layer. To make it capable of working as a gas sensor, an additional sensitive layer for adsorption is used. A 0.51-μm-thin film of polymer-sensitive layer (polyisobutylene, PIB) is used on the top electrode. The adsorption of CH2Cl2 (dichloromethane, DCM) prompts the change in density of the PIB layer, which causes the change in resonance frequency of the FBAR. The simulation results have shown the sensitivity of 450 Hz/ppm for gas sensing for the above-mentioned structure. The sensitivity of the sensor depends on the characteristic frequencies of the device, which are further the function of the thickness of the resonating structure. No involvement of a harsh etching process in fabrication, in addition to immense sensitivity and quality factor, makes this sensor relevant for DCM sensing. © 2017 Society of Photo-Optical Instrumentation Engineers (SPIE).

World University root node

Journal of Micro/ Nanolithography, MEMS, and MOEMS

FEM modeling of solidly mounted film bulk acoustic resonator and gas sensor using PIB-sensitive layer

HfO2 thin films (100 nm) has been deposited by sputtering technique and further annealed at various temperatures ranges from 400 to 1000 °C with increment of 200 °C in N2 ambient for 10 min. The samples have been characterized using XRD, FTIR, EDX, AFM and Laser Ellipsometry. Structural properties of thin film such as crystallite size, phase, orientation and stress have significantly influenced by process parameters viz., annealing temperature as well as by ambient conditions. The electrical properties of thin films have strong dependence on the arrangement of atoms. AFM data shows the size of nanoparticles increase with annealing temperature i.e. 38–53 nm. Due to post deposition annealing treatment in N2 ambient, the structural properties i.e. crystal size as well as stress and the electrical properties viz., refractive index at 632 nm wavelength, roughness are highly influenced. For better quality of thin film, it is desired to have a close match of interplanar spacing with standard International Centre for Diffraction Data so that film can deposit without lattice mismatch. Due to close match of interplanar spacing in N2 ambient in comparison to O2 ambient, it is concluded that HfO2 thin film annealed in N2 ambient shows better structural properties as well as electrical properties. © 2016, Springer Science+Business Media New York.

Journal of Materials Science: Materials in Electronics

Impact of post deposition annealing in N2 ambient on structural properties of nanocrystalline hafnium oxide thin film

Thin film bulk acoustic resonator (FBAR) higher quality factor (Q) provides steep skirt and low insertion losses in the pass band. In this paper, three different loss sources are identified and FBAR is design and simulated in order to reduce the losses. Firstly, the FBAR’s top electrode is simulated for the areas of 150 × 150, 300 × 300 and 400 × 400 μm2 and the quality factor is improved as the area increased to 102, 432.6 and 743.7 respectively. The impedance of the FBAR is reduced as the area of the electrode is increased. Secondly, the anchor width is reduced from 60 to 45 μm and the quality factor is increased from 341 to 432.6 respectively. The losses through the anchor reduce as the anchor reduces. Electrode area and anchor area simulation are showing the notable effect and no other paper is reported for the comparison. Thirdly, the damping factor coefficient (β) is varied as 4.7e−14, 3.84e−14 and 2.5e−14. The quality factor is increased as the damping factor reduces and reported as 283.2, 341.2 and 444.5 respectively. The damping reduction leads the FBAR structure to vibrate more freely at the resonance. The losses through damping are reduced and more energy has stored at the resonance so it increases the quality factor. © 2017, Metrology Society of India.

Mapan - Journal of Metrology Society of India

Design and Simulation of FBAR for Quality Factor Enhancement

Brain Computer Interface (BCI) has recently gained much popularity due to plethora of its applications. In this paper, we propose a novel system architecture to utilize brain signals for controlling Internet of Things enabled environments. The proposed architecture aids in translating brain signals to commands that interact with or control the environment using IoT actuation networks thus executing user desired actions. It comprises of novel, low complex and low power intelligent signal processing architecture for detection of voluntary eye blinks by isolating involuntary eye blinks and IoT enabled wireless actuation network for controlling the environment using commands generated from EEG signal. For the real time performance analysis of the proposed architecture, we developed a wearable device which acquires dual channel EEG using electrodes at Fp1 and Fp2 locations. From the acquired EEG data, the device detects the voluntary eye blinks of the patient and use this information in controlling the environment such as switching HVAC system, lighting or electric fan etc. Performance analysis shows that the proposed intelligent signal processing architecture detects the voluntary eye blinks with 95.2% accuracy when tested on 10 subjects with a low power consumption of 165 mW. © 2017 IEEE.

2017 IEEE 19th International Conference on e-Health Networking, Applications and Services, Healthcom 2017

A novel system architecture for brain controlled IoT enabled environments

This paper presents bearing fault detection and its diagnosis in a three phase induction motor using Stockwell transform of stator currents. The maximum magnitude and maximum phase angle plots are obtained from S-transform for various bearing conditions both on shaft-side and fan-side. The standard deviation of these plots are utilized to detect and analyze the bearing faults. The various bearing faults analyzed under case studies include defects in innerrace, outerrace, cage and balls. The experimental study shows that the S-transform based feature extraction can be effectively utilized for bearing fault detection and diagnosis in three phase induction motor. © 2016 IEEE.

2016 IEEE Annual India Conference, INDICON 2016

Bearing fault diagnosis of a three phase induction motor using stockwell transform

This paper presents the experimental investigation of power quality (PQ) disturbances associated with the grid integrated wind energy generator. PQ disturbances associated with the grid synchronization and outage of doubly fed induction generator (DFIG) based wind energy generation system have been investigated in the presence of various types of loads. The voltage signal has been captured at point of common coupling (PCC) using the data acquisition system consisting of power quality analyser, laptop, and WT viewer software. The voltage signal has been analysed using MATLAB software to find the PQ disturbances. It has been observed that the PQ disturbances such as voltage fluctuations, flicker, voltage sag, voltage swell and harmonics are associated with the grid synchronization and outage of DFIG based wind energy conversion system. © 2017 IEEE.

2017 4th International Conference on Advanced Computing and Communication Systems, ICACCS 2017

Experimental investigation of power quality disturbances associated with grid integrated wind energy system

Use of open channel communication in automatic generation control (AGC) of interconnected power systems leads to time delay in the secondary frequency control loop. Such time delayed AGC of a power system can lead to unstable operation. This paper presents an insight on how gain tuning approaches need to be changed from single objective to multi objective in order to achieve stable operation as well as fast frequency and tie power regulation. The analysis is performed on a single area hydro power system. The effect of secondary controller gains on conventional gain tuning objective function, integral squared error (ISE), and on the communication delay margin has been shown in this work. The paper concludes that while a particular set of proportional integral (PI) secondary controller gain can give least ISE value; the same can give rise to stability issues due to reduction in delay margin. It is discussed that a tradeoff is needed between improvement in ISE and improvement in delay margin. Thus, the paper proposes to use multi objective optimization for PI controller gains where one objective is to minimize the ISE while the other is to maximize the delay margin. © 2017 IEEE.

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Multi objective gain tuning approach for time delayed automatic generation control

A method based on Stockwell's transform and Fuzzy C-means (FCM) clustering initialized by decision tree has been proposed in this paper for detection and classification of power quality (PQ) disturbances. Performance of this method is compared with S-transform based ruled decision tree. PQ disturbances are simulated in conformity with standard IEEE-1159 using MATLAB software. Different statistical features of PQ disturbance signals are obtained using Stockwell's transform based multi-resolution analysis of signals. These features are given as input to the proposed techniques such as rule-based decision tree and FCM clustering initialized by ruled decision tree for classification of various PQ disturbances. The PQ disturbances investigated in this study include voltage swell, voltage sag, interruption, notch, harmonics, spike, flicker, impulsive transient and oscillatory transient. It has been observed that the efficiency of classification based on ruled decision tree deteriorates in the presence of noise. However, the classification based on Fuzzy C-means clustering initialized by decision tree gives results with high accuracy even in the noisy environment. Validity of simulation results has been verified through comparisons with results in real time obtained using the Real Time Digital Simulator (RTDS) in hardware synchronization mode. The proposed algorithm is established effectively by results of high accuracy to detect and classify various electrical power quality disturbances. © 2017 Elsevier B.V.

Applied Soft Computing Journal

Recognition of power quality disturbances using S-transform based ruled decision tree and fuzzy C-means clustering classifiers

This study presents a wavelet-alienation based algorithm for protection of two terminal transmission line. The proposed algorithm makes use of wavelet transform based approximate coefficients of three-phase voltage and current signals, obtained over a quarter cycle to detect, classify and locate various faults. Detection and classification of these faults are achieved with the help of alienation coefficients of current signals from both the terminals of the transmission line. The approximate coefficients of voltage and current signals, obtained over a quarter cycle, are fed to artificial neural network to locate the faults precisely. The proposed algorithm has been tested successfully for various types of faults with the variations in location, inception angle and fault impedance. © The Institution of Engineering and Technology 2016.

IET Generation, Transmission and Distribution

Wavelet-alienation based transmission line protection scheme

This paper studies collective formations of multi-agent systems, modeled with unicycle dynamics, while admitting heterogeneity in both controller gains and speeds of the agents along with saturation on the controller outputs. This addresses a practical scenario where the speeds are usually nonidentical and the controller gains may vary due to imperfect implementation. The paper analyzes the effect of both heterogeneous controller gains and speeds simultaneously on the collective formations obtained by optimizing the average linear momentum of the group of agents. A detailed analysis of the two-agent system is given in the paper and some results on the locus of the collective centroid with varying controller gains are obtained. Effect of saturation is also studied for two cases when the controller gains are bounded and when the control efforts are bounded. Simulation examples are given to illustrate the theoretical findings. © 2017 The Franklin Institute