M.Tech. Project Session (2012-13) : Topic #1Project Title: “Modelling of MOSFET Embedded Sensor for MEMS applications.”Supervisor: B.S. Panwar.Objective: Modelling and simulation of strain-induced mobility of a MOSFET asfunction of applied stress.Summary:Sensing mechanism is one of the most important issues in the field of sensors. Severaltransduction mechanisms are available in literature which includes optical detection,capacitive, piezoelectric and piezoresistive sensing. Recently, embedded transistor technique is reported in which there is a change in the carrier mobility and drain current of a metaloxide semiconductor field effect transistor (MOSFET) when stress is applied. A novelMOSFET pressure sensor was proposed based on the MOSFET stress sensitive phenomenon,in which the source-drain current changes with the stress in channel region. The use ofpiezoresistance model to describe the stress induced carrier mobility change has also beenreported [2-4]. Two MOSFET’s and two piezoresistors were employed to form a Wheatstonebridge served as sensitive unit in the novel sensor . The use of MOSFETs for strainsensing will have the following advantages of high sensitivity, low cost, easy integration oflow power CMOS electronics with the MEMS sensors and less complicated signalconditioning circuitry.References: G. Shekhawat, S.H. Tark, and V.P. Dravid, “MOSFET embedded microcantileversfor measuring deflection in biomolecular sensors,” Science, vol. 311, pp. 1592-95, 2006. S. Suthram, J.C. Ziegert, T. Nishida, and S.E. Thompson, “Piezoresistancecoefficients of (100) silicon nMOSFETs measured at low and high (~1.5 GPa) channelstress,” IEEE Electron Device Letters, vol. 28, no. 1, 2007. Y.L. Tsang, A.G. O’Neill, B.J. Gallacher, and S.H. Olsen, “Using piezoresistancemodel with C-R conversion for modelling of strain-induced mobility,” IEEE Electron DeviceLetters, vol. 29, no. 9, 2008 J.S. Wang, W.P. Chen, C. Shih, C. Lein, P. Su, Y. Sheu, D.Y. Chao, and K. Goto,“Mobility modelling and its extraction technique for manufacturing strained-Si MOSFETs,”IEEE Electron Device Letters, vol. 28, no. 11, 2007. Z.H. Zhang, Y.H. Zhang, L.Liu, T.L. Ren, “A Novel MEMS Pressure Sensor withMOSFET on Chip,” IEEE SENSORS Conference, 2008.
M.Tech. Project Session (2012-13): Topic #2Project Title: “Modeling of Piezoelectric (PZT) materials for actuation of various MEMSstructures.”Supervisor: B. S. Panwar.Objective:(1) Modeling and simulation of PZT actuated catilevers and diaphragms for MEMSbased Resonators for force and mass sensing applications.(2) Integration of these PZT MEMS structures with CMOS based differential amplifier.Short description:Microcantilevers, bridges and diaphragms are the most simplified and common MEMSstructures in the field of micromachined transducers. These MEMS structures are relativelysimple and inexpensive to fabricate and analytical solutions of their displacement profiles andstress distributions under load are well developed. These structures are commonly used asforce and displacement sensors as well as mass sensors when excited in resonance. Whenused in dynamic or resonance mode, these structures are mechanically deflected by differentactuation techniques, piezoelectric being most commonly used. Numerous microcantileverdevices have been implemented for ultra low mass sensing for biological and chemicalapplications [1,2]. The motion of a cantilever beam can be sensitively monitored by means ofa variety of techniques, such as variations in piezoresistivity, piezoelectricity, capacitivemethod, optical beam deflection and embedded transistor semiconductivity. This work willalso emphasize on the embedded MOSFET sensing technique. In order to reduce the numberof off-chip components required to operate a sensing system, more and more microelectronicbuilding blocks are integrated together with the microsensor on the same chip [3,4]. In thisproject work we propose the integration of PZT actuated MEMS structures with a CMOSbased differential amplifer which will amplify only the difference signal of the sensing andthe reference sensors, and also minimizes systematic noise and environmental perturbations.Use of embedded MOSFET sensing technique will further ease the integration of low powerCMOS electronics and MEMS structure.References: Y. T. Yang, C. Callegari, X. L. Feng, K. L. Ekinci, and M. L. Roukes, “Zeptogram-ScaleNanomechanical Mass Sensing,” Nano Lett., Vol. 6, No. 4, 2006. B. Ilic, and H. G. Craighead, “Attogram detection using nanoelectromechanicaloscillators,” J. Applied Physics Vol. 95, No. 7, 2004. G.K. Fedder, R.T. Howe, T.J.K. Liu, and E.P. Quevy, “Technologies for CofabricatingMEMS and Electronics,” Proceedings of the IEEE, Vol. 96, No. 2, 2008. O. Brand, “Microsensor Integration Into Systems-on-Chip,” Proceedings of the IEEE,Vol. 94, No. 6, June 2006.
M.Tech. Project Session (2012-13): Topic #3Project Title: “Design Optimization of Piezoelectric Energy Harvester”Supervisor: B. S. Panwar.Objective: Virtualization of Piezoelectric Energy Harvester Design Using COMSOL,MATLAB interface with Power Management CircuitProject Summary In the present work a comprehensive literature survey is to be completed and the issues that need to be addressed to bring the MEMS based energy harvesting systems a viable system for charging of wireless sensors nodes and cellular phones is to be examined. This project will concentrate on the optimization of PZT micro-cantilever geometry to convert the mechanical vibrations to electrical signal using Data Acquisition Toolbox for connecting MATLAB to data acquisition hardware. This methodology requires interface of PZT micro-cantilever design software with MATLAB which can be connected to the power management circuit using the appropriate sampling rate data acquisition card. This will facilitate conversion of simulated mechanical vibrations to an electrical signal, which can be used to drive the power management circuit. There is large number of options for ac/dc conversion architecture. The best architecture need to be identified analyzed and interfaced with the virtual design philosophy using COMSOL and DATA acquisition Tool Box of MATLAB. In this process a virtual design platform is to be formed which interfaces the COMSOL design tools with the power management circuit using a data acquisition card. A typical block diagram of such a configuration is shown below: The definition and scope of work can be described as below: 1. Establishing the interface between the cantilever design tools COMSOL with MATLAB using the Data Acquisition Tool box. 2. Identification and selection of proper sampling rate data acquisition card and establishing its functionality with the personal computer or laptop. 3. Interface of the ac signal obtained from DAQ interfaced with Personal Computer and analyzing the complete structure using the Simulink Design Tools. 4. Optimizing the geometry of the piezoelectric energy harvester to get the maxm. power delivered to the battery for charging.
M.Tech. Project Session (2012-13): Topic #4Project Title: “Design and Implementation of Wireless Body Area Network ”Supervisor: B. S. Panwar.Objective: Developing a patient monitoring system using body area network.Project SummaryDesign and implementation of a Wireless Body Area Network for health careapplications:Patient monitoring in a hospital environment is becoming more and more complex withmultiple parameters (ECG, EEG, temperature, pressure, etc) to be measured and the need tonetwork the data gathered from many patients for observation at a central monitoring station.The objective of present project is to design a wireless communication protocol for themultiplexing of data gathered from multiple patients and to use a fiber optic link to collect themultiplexed data streams and transmit them to the monitoring station for analysis andinterpretationThe work will involve selection and acquisition of biomedical sensors, development ofhardware for data processing and RF interface for wireless communications. Differentmultiplexing approaches like TDMA, FDMA, CDMA, SDMA will be investigated and thebest one implemented. The multiplexed data streams will be collected together and fed to afiber optic communication link for data transmission to the sink node. MATLAB will be usedwith an appropriate DAQ for data acquisition, display, monitoring and analysis.This is hardware based project and efforts will be made to develop a prototype of theproposed system and test it in a realistic environment.
M.Tech. Project Session (2012-13): Topic #5Project Title: “SAW based wireless sensor Netwrok ”Supervisor: B. S. Panwar.Objective: Developing wirelessly interrogatable sensor network.Project SummaryDevelopment of a passive, wirelessly interrogable sensor network based on SAWdevices:In harsh industrial environments like high temperature , pressure, radiation, moving machineparts, etc, it is impossible to use conventional semiconductor based sensors with wiredconnections. Sensors need to be embedded in structures like bridges and implanted inpatients for health care applications which requires battery less operation (for a long lifetime).Surface Acoustic Wave technology provides us with a wide variety of passive, wirelesslyinterrogable sensors, based on wide band delay lines and narrow band resonators, which areable to operate satisfactorily in extremely harsh environments.The objective of the present project will be to design and fabricate SAW sensors for detectionof temperature, pressure, gases, etc using delay lines and resonators. The reader electronicswill be developed to wirelessly interrogate the SAW sensors and extract information fromthem. To increase the number of sensors in the network, multiple access schemes like TDMA,FDMA, CDMA, SDMA will be studied and developed.At the end of the project, we should have some SAW based sensors and electronics forinterrogating them. It should be possible to demonstrate the interrogation of multiple SAWsensors using an appropriate multiple access scheme.
M.Tech. Project Session (2012-13): Topic #6Project Title: “Evolving New Techniques of Recording Brain Waves and Telepathy aFuture Mode of Communication”Supervisor: B. S. Panwar, and Dr. Puneet Agarwal- Senior Neurologist Max HospitalObjective: Analysis of recorded brain waves for predicting mental disorder and proposingbrain waves a Future Mode of Communication”Project Summary:To record the brain waves with newer techniques in more comprehensive and sensitivemanner so that we can detect different neurological and even mental disorders (psychiatric) invery early stage which will help in treatment as well as in prevention.The project can be outlined as below: 1. A comprehensive survey on the tools and techniques of recording brain waves. 2. Analysis using standard signal processing tools for finding the deviations in the recorded brain waves Delta, Theta, Alpha, Beta and Gamma for a normal and a person having mental disorder. 3. Proposing new techniques of recording brain waves to record the electrode potential in graded manner, recording ultrasounds accounting for movement of different parts of the brain. 4. High speed digital recording of EEG signals for improved interpretation and diagnostics. 5. Exploring telepathy as the future mode of communications.