References of "IEEE Sensors Journal"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAn investigation of structural dimension variation in electrostatically-coupled MEMS resonator pairs using mode-localization
Wood, Graham; Chun, Zhao; Pu, Suan et al

in IEEE Sensors Journal (2016)

If a pair of MEMS resonators are electrostatically coupled together, the vibration amplitude ratios at the resonant frequencies of the resulting coupled system are sensitive to stiffness perturbation. An ... [more ▼]

If a pair of MEMS resonators are electrostatically coupled together, the vibration amplitude ratios at the resonant frequencies of the resulting coupled system are sensitive to stiffness perturbation. An imbalance between the two resonators causes the confinement of vibration energy when the system is resonating, an effect known as mode-localization. The degree of localization can be determined by extracting the amplitude ratio of the resonators through capacitive transduction. In this paper, we have fabricated MEMS devices, using a dicing-free silicon-on-insulator process, consisting of pairs of closely spaced microresonators. Each resonator consists of a clamped-clamped beam with a wider section in the middle, which is the location of the electrostatic coupling, instituted through the DC biasing of the resonators. Several devices have been fabricated, with the length of the anchor beams being varied, which influences the frequency of resonance. Stiffness imbalance between the resonators has been introduced through electrostatic spring softening, with the sensitivity of the amplitude ratio of the resonant mode shape being greater for the higher frequency, shorter anchor devices. The sensitivities of the devices in this study have been found to be 9 times greater than state-of-the-art two-degree-of-freedom mode-localized sensors. [less ▲]

Detailed reference viewed: 5 (1 ULg)
Full Text
Peer Reviewed
See detailElectromechanical Sigma-Delta Modulators (EMSDM) force feedback interfaces for capacitive MEMS inertial sensors: a review
Chen, Fang; Li, Xinxin; Kraft, Michael ULg

in IEEE Sensors Journal (2016)

Analog-to-digital converters (ADC) based on sigma-delta modulators (SDM) are a popular choice for high resolution conversion from the analog to the digital domain. With relatively small modifications they ... [more ▼]

Analog-to-digital converters (ADC) based on sigma-delta modulators (SDM) are a popular choice for high resolution conversion from the analog to the digital domain. With relatively small modifications they also can be used as electromechanical SDM (EM-SDM) force feedback interfaces for capacitive micro-electromechanical systems (MEMS) inertial sensors. Such interfaces are able to combine the benefits of force feedback and analog to digital conversion at relatively modest circuit cost. This paper provides a comprehensive review of EM-SDM interfaces for capacitive MEMS inertial sensors. The principle and design methodology of EM-SDM interfaces are introduced. A classification of EM-SDMaccelerometers and gyroscopes is presented, and a detailed analysis of different EM-SDMarchitectures is given. The most representative EM-SDM inertial sensors systems are discussed and compared with regard to their performance characteristics. In particular, the properties of various discrete and continuous-time techniques and a system parameter optimization methodology are illustrated through specific examples. Finally, current challenges and future development trends of EM-SDM interfaces for inertial sensors have been identified. [less ▲]

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailEnzyme sensor with Polydimethylsiloxane membrane and CMOS potentiostat for wide-range glucose measurements.
Mross, Stefan; Fuerst, Peter; Pierrat, Sebastien et al

in IEEE Sensors Journal (2015), 15(12), 7096-7104

We report on an electrochemical measurement setup comprising a glucose sensor and a CMOS potentiostat with a two-layer membrane as the first steps toward the development of an integrated in-situ sensor ... [more ▼]

We report on an electrochemical measurement setup comprising a glucose sensor and a CMOS potentiostat with a two-layer membrane as the first steps toward the development of an integrated in-situ sensor system for bioreactors. The potentiostat has a chip size of 2.1 mm× 2.5 mm and a linear current range from −220 nA to 240 nA with a linearity of R2 = 0.9995. For wide range measurements of glucose concentrations in cell culture media, electrodes functionalized with the enzyme glucose oxidase were spin-coated with membranes made from polydimethylsiloxane (PDMS). A two-stage curing scheme of the PDMS was applied, and different membrane thicknesses and curing times were evaluated. With these membranes, glucose concentrations up to 500 mM were measured with a linear measurement range up to 200 mM. The sensors were successfully employed in the glucose monitoring of a culture of Saccharomyces cerevisiae to monitor the glucose consumption of the cells. For interference elimination, the cellulose acetate membranes were employed. [less ▲]

Detailed reference viewed: 43 (2 ULg)
Full Text
Peer Reviewed
See detailDesign and implementation of an optimized double closed-loop control system for MEMS vibratory gyroscope
Chen, Fang; Yuan, Weizheng; Chang, Honglong et al

in IEEE Sensors Journal (2014), 14(1), 184--196

Detailed reference viewed: 20 (0 ULg)
Full Text
Peer Reviewed
See detailTwo-mass MEMS velocity sensor: internal feedback loop design
Alshehri, Ali; Kraft, Michaël ULg; Gardonio, Paolo

in IEEE Sensors Journal (2013), 13(3), 1003--1011

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailA high-resolution silicon-on-glass z axis gyroscope operating at atmospheric pressure
Ding, Haitao; Liu, Xuesong; Lin, Longtao et al

in IEEE Sensors Journal (2010), 10(6), 1066--1074

This paper describes a high-resolution silicon-on-glass <i>z</i> axis gyroscope operating at atmospheric pressure. The mechanical structure is designed in such a way that it exhibits low cross coupling ... [more ▼]

This paper describes a high-resolution silicon-on-glass <i>z</i> axis gyroscope operating at atmospheric pressure. The mechanical structure is designed in such a way that it exhibits low cross coupling between drive and sense mode of less than 0.5\% simulated using finite-element method and 1.35\% verified by experimental measurements. Due to a symmetrically designed structure, the specified bandwidth can be maintained despite of fabrication imperfections. The fabrication process flow is based on a combination of silicon on glass bonding and deep reactive ion etching which results in a large proof mass and capacitances. A closed loop self-oscillation drive interface is used to resonate the gyroscope in the drive mode, which reaches steady-state after 150 ms. Using area-varying capacitors, large quality factors of 217 and 97 for drive and sense mode, respectively, were achieved operating at atmospheric pressure. A low drive voltage, with a 1 V<sub>peak-peak</sub> AC drive amplitude and 10 V DC bias was used to excite the drive mode. The measured scale factor was 10.7 mV/\^A°/s in a range of \^A$\pm$300\^A°/s with a <i>R</i> <sup>2</sup>-nonlinearity of 0.12\%. The noise equivalent angular rate is 0.0015\^A°/s/Hz<sup>1/2</sup> (=5.4\^A°/h/Hz<sup>1/2</sup>) in a 50 Hz bandwidth. The measured SNR was 34 dB at an angular rate input signal with an amplitude of 12.5\^A°/s and a frequency of 10 Hz. Without any active temperature control, zero bias stability of 1\^A°/s was achieved for long-term measurements over six hours and 0.3\^A°/s for short-term measurements over 120 seconds (1-\^A?`). [less ▲]

Detailed reference viewed: 69 (0 ULg)
Full Text
Peer Reviewed
See detailA simple, low-cost double beam spectrophotometer for colorimetric detection of nitrite in seawater
Gong, Weidong; Mowlem, M.; Kraft, Michaël ULg et al

in IEEE Sensors Journal (2009), 9(7), 862--869

This paper reports on the optical detection system of a prototype nitrite sensor for seawater analysis. The sensor uses a colorimetric Griess reaction that produces an Azo dye with an absorption peak at ... [more ▼]

This paper reports on the optical detection system of a prototype nitrite sensor for seawater analysis. The sensor uses a colorimetric Griess reaction that produces an Azo dye with an absorption peak at 540 nm. A simple low-cost double beam spectrophotometer using a green light emitting diode (LED) light source, two integrated photo detectors and lock-in detection is described. A log-ratio amplifier is used to produce an output proportional to absorbance. The optical devices were mounted in a cast resin block to prevent shock and vibration. Experimental results show the detection system has a limit of detection of 0.1 muM. [less ▲]

Detailed reference viewed: 21 (0 ULg)
Full Text
Peer Reviewed
See detailRELIABILITY ACCELERATED TESTING OF MEMS ACCCELEROMETERS
Bazu, Marius; Gălăţeanu, Lucian; Ilian, Virgil Emil et al

in IEEE Sensors Journal (2007), 1

An attempt to assess the reliability of a batch of MEMS accelerometers is presented. The testing plan is application oriented and contains combined tests: thermal and mechanical stresses (two variants ... [more ▼]

An attempt to assess the reliability of a batch of MEMS accelerometers is presented. The testing plan is application oriented and contains combined tests: thermal and mechanical stresses (two variants: vibration and tilting) were used. The results demonstrated the good reliability of the tested device, the failure rate being smaller than 6.10-8h-1. [less ▲]

Detailed reference viewed: 41 (3 ULg)
Full Text
Peer Reviewed
See detailMicromachined vibratory gyroscopes controlled by a high-order bandpass sigma-delta modulator
Dong, Yufeng; Kraft, Michaël ULg; Redman-White, William

in IEEE Sensors Journal (2007), 7(1), 59--69

This work reports on the design of novel closed-loop control systems for the sense mode of a vibratory-rate gyroscope based on a high-order sigma-delta modulator (SigmaDeltaM). A low-pass and two ... [more ▼]

This work reports on the design of novel closed-loop control systems for the sense mode of a vibratory-rate gyroscope based on a high-order sigma-delta modulator (SigmaDeltaM). A low-pass and two distinctive bandpass topologies are derived, and their advantages discussed. So far, most closed-loop force-feedback control systems for these sensors were based on low-pass SigmaDeltaM's. Usually, the sensing element of a vibratory gyroscope is designed with a high quality factor Q to increase the sensitivity and, hence, can be treated as a mechanical resonator. Furthermore, the output characteristic of vibratory rate gyroscopes is narrowband amplitude-modulated signal. Therefore, a bandpass SigmaDeltaM is a more appropriate control strategy for a vibratory gyroscope than a low-pass SigmaDeltaM. Using a high-order bandpass SigmaDeltaM, the control system can adopt a much lower sampling frequency compared with a low-pass SigmaDeltaM while achieving a similar noise floor for a given oversampling ratio (OSR). In addition, a control system based on a high-order bandpass SigmaDeltaM is superior as it not only greatly shapes the quantization noise, but also alleviates tonal behavior, as is often seen in low-order SigmaDeltaM control systems, and has good immunities to fabrication tolerances and parameter mismatch. These properties are investigated in this study at system level [less ▲]

Detailed reference viewed: 25 (0 ULg)