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On behalf of the Organising Committee of the 10th IEEE SENSORS Conference 2011, it is a great honour and pleasure to welcome you to the University of Limerick (UL) located on the outskirts of the historic City of Limerick as well as the beautiful surrounding Shannon region, Ireland.
This paper focuses on an ultra-sensitive H2 sensor fabricated using a time and cost-effective method. The sensor is comprised of Pd nanowires fabricated using λ-DNA templates. The morphology and the electrical characterisation of the metalized DNA nanowires (diameter = 5–45nm) were investigated by AFM and conductive AFM (cAFM). The conductivity of a single Pd-DNA nanowire, 127 Scm−1 was substantially...
In this article we report hydrogen sensing property of WO3/MWNTs thin films that were fabricated by spin-coating on alumina substrates. The MWNTs were initially functionalized (f-MWNTs) to enhance dispersion in the sol of multiwalled carbon nanotubes (MWNTs) and tungsten trioxide (WO3). Microstructure, morphology and chemical composition of the materials were characterized by SEM, TEM, XRD and XPS...
In this paper, a comparative study of Pt/nanostructured MoO3/SiC Schottky diode based hydrogen gas sensors is presented. MoO3 nanostructured films with three different morphologies (nanoplatelets, nanoplatelets-nanowires and nano-flowers) were deposited on SiC by thermal evaporation. We compare the current-voltage characteristics and the dynamic response of these sensors as they are exposed to hydrogen...
This work demonstrates the potential of thermally actuated micro-electromechanical resonators to be used as highly sensitive and fast sensors distinguishing between different gases and gas mixtures based on their thermo-physical properties. This approach is especially suitable for detection of hydrogen due to its extremely high thermal conductivity compared to other gases. On the other hand, as observed...
This paper reports on mode matching of a MEMS gyroscope using simplified displacement feedback and reduces the frequency split between the two modes to less than 0.01 Hz. Mode matching is shown to improve the gyro performance significantly and reduce the bias stability from 3 degree/hour to 0.5degree/hour. The displacement feedback matching scheme provides an in situ matching control that may augment...
This paper presents a method of regulation and maximization of Q-factor in anti-phase driven tuning fork MEMS. Non-symmetric regulation of stiffness in coupled 2-DOF resonators using the negative electrostatic spring effect is shown to adjust the momentum misbalance caused by fabrication imperfections in nominally symmetric structures. Balancing the structure through stiffness matching minimizes the...
This work demonstrates the implementation of a functional kinetic energy harvester designed to power wireless sensor electronics used in vehicular applications. The design, fabrication, and experimental characterization of a complete electrodynamic (magnetic) energy harvesting system capable of delivering in excess of 10 mW from 100 milli-g's of acceleration is presented. Unlike previous energy harvesting...
In vibration energy harvesting, for the generators to be efficiently applicable over a range of source frequencies, many methods can be adopted, among which the use of array of converters with different resonance frequencies has been reported as particularly effective. However, for a given excitation frequency only one single converter at a time contributes to the power generation, with a corresponding...
An energy harvesting system including a novel front-end multi-stage rectifier (AC-DC) charge pump, a power management, low-dropout voltage regulator (LDO) and a battery charger is presented in this work. The designed circuit is realized by the TSMC 0.35um CMOS process. The proposed circuit system is suitable for harvesting the low-frequency vibration energy in portable medical sensors or low-power...
This paper describes a reliable modeling technique for piezoelectric transducers and a procedure for identifying model parameters with few simple measurements and standard laboratory equipment. Direct measurements were taken on commercial Q220-A4-303YB piezoelectric transducers from Piezo Systems in a cantilever configuration with tip masses from 6 g to 18 g. For validation purposes, the behavior...
Terahertz sensing is used for detection of hidden objects, explosives and biological and chemical hazardous agents, and for applications in radio astronomy, space research, biology and medicine. Emerging THz transistor sensing technology uses the rectification of electron density oscillations in short channel Si CMOS and FIN FETs and III–V and III–N High Electron Mobility Transistors (HEMTs). Such...
Recent advances in materials and device structures for terahertz imaging and sensing technology are reviewed. The fundamental physical principle for terahertz imaging/sensing is focused on the nonlinear dynamics of plasmons in two-dimensional semiconductors including quantum wells in III–V based heterostructures as well as graphene.
Millimetre-wave- and terahertz sensors are a premier choice for the non-destructive inspection of letters and parcels as well as the control of products. A small versatile scanner ahs been developed, which allows to demonstrate this capability. The scanner employs mechanical scanning in transmission geometry, the transmitter ans receiver located at two rotating discs facing its other with the test...
We demonstrate terahertz (THz) frequency imaging and sensing using a single quantum cascade laser (QCL) device for both generation and sensing of THz radiation. Detection is achieved by utilising the effect of self-mixing in the THz QCL, and specifically by monitoring perturbations to the voltage across the QCL induced by light reflected from an external object back into the laser cavity. Self-mixing...
The detection of THz radiation, until recently the domain of specialized technologies, is now becoming linked to main-stream silicon CMOS technology, which entails significant advantages concerning costs, reliability, function integration, etc. Following the prediction that field-effect transistors (FETs) can detect THz radiation far above their cut-off frequency by a mixing process involving plasma...
The dramatically increasing rate of urbanization is driving demand for more intelligent urban and environmental systems. City leaders and service providers are looking to base decisions on data, and to so, are deploying sensors extensively. However, even the most advanced cities are having difficulties assimilating and analyzing data collected from these sensors. In this talk, I will describe research...
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