J.T.M. van Beek

Bio: J.T.M. van Beek is an academic researcher from NXP Semiconductors. The author has contributed to research in topics: Resonator & Capacitive sensing. The author has an hindex of 19, co-authored 44 publications receiving 1427 citations. Previous affiliations of J.T.M. van Beek include TSMC & Philips.

A review of MEMS oscillators for frequency reference and timing applications

Abstract: MEMS-based oscillators are an emerging class of highly miniaturized, batch manufacturable timing devices that can rival the electrical performance of well-established quartz-based oscillators. In this review, a description is given of the key properties of a MEMS resonator that determine the overall performance of a MEMS oscillator. Piezoelectric, capacitive and active resonator transduction methods are compared and their impact on oscillator noise and power dissipation is explained. An overview is given of the performance of MEMS resonators and MEMS-based oscillators that have been demonstrated to date. Mechanisms that affect the frequency stability of the resonator, such as temperature-induced frequency drift, are explained and an overview is given of methods that have been demonstrated to improve the frequency stability. The aforementioned performance indicators of MEMS-based oscillators are benchmarked against established quartz and CMOS technologies.

Piezoresistive heat engine and refrigerator

Abstract: Heat engines provide most of our mechanical power and are essential for transportation on the macroscopic scale. However, although significant progress has been made in the miniaturization of electrostatic engines, it has proved difficult to reduce the size of liquid- or gas-driven heat engines below 107 μm3. Here we demonstrate that a crystalline silicon structure operates as a cyclic piezoresistive heat engine when it is driven by a sufficiently high d.c. current. A 0.34 μm3 engine beam draws heat from the d.c. current using the piezoresistive effect and converts it into mechanical work by expansion and contraction at different temperatures. This mechanical power drives a silicon resonator of 1.1×103 μm3 into sustained oscillation. Even below the oscillation threshold the engine beam continues to amplify the resonator’s Brownian motion. When its thermodynamic cycle is inverted, the structure is shown to reduce these thermal fluctuations, therefore operating as a refrigerator. A micrometre-scale device that exploits the piezoresistive characteristics of silicon acts like an engine, converting heat into mechanical work in one mode of operation, and, in another, like a refrigerator, suppressing mechanical fluctuations.

Medium Energy Neutral Atom (MENA) Imager for the Image Mission

Abstract: The Medium Energy Neutral Atom (MENA) imager was developed in response to the Imaging from the Magnetopause to the Aurora for Global Exploration (IMAGE) requirement to produce images of energetic neutral atoms (ENAs) in the energy range from 1 to 30 keV These images will be used to infer characteristics of magnetospheric ion distributions The MENA imager is a slit camera that images incident ENAs in the polar angle (based on a conventional spherical coordinate system defined by the spacecraft spin axis) and utilizes the spacecraft spin to image in azimuth The speed of incident ENAs is determined by measuring the time-of-flight (TOF) from the entrance aperture to the detector A carbon foil in the entrance aperture yields secondary electrons, which are imaged using a position-sensitive Start detector segment This provides both the one- dimensional (1D) position at which the ENA passed through the aperture and a Start time for the TOF system Impact of the incident ENA on the 1D position-sensitive Stop detector segment provides both a Stop-timing signal and the location that the ENA impacts the detector The ENA incident polar angle is derived from the measured Stop and Start positions Species identification (H vs O) is based on variation in secondary electron yield with mass for a fixed ENA speed The MENA imager is designed to produce images with 8 4 angular resolution over a field of view 140 360, over an energy range from 1 keV to 30 keV Thus, the MENA imager is well suited to conduct measurements relevant to the Earth's ring current, plasma sheet, and (at times) magnetosheath and cusp

Dynamics and squeeze film gas damping of a capacitive RF MEMS switch

Abstract: We report on measurements of the time-dependent capacitance of an RF MEMS shunt switch. A high time-resolution detection set-up is used to determine switching time and motion of the device. From the equation of motion the damping force is extracted. The measured damping force is found to be approximately proportional to the speed over the gap to the third power (FD v/z3), in good agreement with squeeze film damping theory. Significant influence of slip–flow effects on the motion is observed. Measurements at low pressure show underdamped harmonic oscillations in the opening motion and contact bounce effects in the closing motion. Effects of dielectric charging on the C–V curves are discussed. Experimental results are compared with electromechanical and damping simulations.

RF MEMS for ubiquitous wireless connectivity. Part II. Application

Abstract: This paper reports on RF-MEMS switchable capacitors, varactors, and ohmic switch technology attribute for both base stations and handsets in realizing frequency-agile RF/wireless systems capable of serving multiple frequency bands. For the handset, this leads to a smaller footprint combined with low power consumption of the RF radio. For the base station the benefit lies in ability for reconfiguration of the air interface, which leads to high logistical savings for infrastructure vendors through a reduction in the number of product variants. Reconfigurable frequency-agile radios are a perfect addition to reconfigurable baseband processing. Both together form the basis of a realistic and reasonable approach to realize software radios.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

A single-atom heat engine

Abstract: Heat engines convert thermal energy into mechanical work and generally involve a large number of particles. We report the experimental realization of a single-atom heat engine. An ion is confined in a linear Paul trap with tapered geometry and driven thermally by coupling it alternately to hot and cold reservoirs. The output power of the engine is used to drive a harmonic oscillation. From direct measurements of the ion dynamics, we were able to determine the thermodynamic cycles for various temperature differences of the reservoirs. We then used these cycles to evaluate the power P and efficiency η of the engine, obtaining values up to P = 3.4 × 10(-22)joules per second and η = 0.28%, consistent with analytical estimations. Our results demonstrate that thermal machines can be reduced to the limit of single atoms.

Realization of a micrometre-sized stochastic heat engine

Abstract: An optically trapped colloidal particle serves as the first realization of a stochastic thermal engine, extending our understanding of the thermodynamics behind the Carnot cycle to microscopic scales where fluctuations dominate.

Electrostatic pull-in instability in MEMS/NEMS: A review

Abstract: Pull-in instability as an inherently nonlinear and crucial effect continues to become increasingly important for the design of electrostatic MEMS and NEMS devices and ever more interesting scientifically. This review reports not only the overview of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices, but also the physical principles that have enabled fundamental insights into the pull-in instability as well as pull-in induced failures. Pull-in governing equations and conditions to characterize and predict the static, dynamic and resonant pull-in behaviors are summarized. Specifically, we have described and discussed on various state-of-the-art approaches for extending the travel range, controlling the pull-in instability and further enhancing the performance of MEMS and NEMS devices with electrostatic actuation and sensing. A number of recent activities and achievements methods for control of torsional electrostatic micromirrors are introduced. The on-going development in pull-in applications that are being used to develop a fundamental understanding of pull-in instability from negative to positive influences is included and highlighted. Future research trends and challenges are further outlined.