H. A. C. Tilmans

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Planar array antennas are attractive for use in future automotive radar systems due to their flexibility in design and control of radar beams. The complexity and cost of a radar front-end phased array can be decreased by applying a beam-steering/switching concept, which reduces the number of parallel RF and baseband signal paths. RF-microelectromechanical(More)
A systematic investigation of the influence of the process parameters temperature, pressure, total gas flow, and SiH 2 Cl 2 :NH 3 gas flow ratio on the residual stress, the refractive index, and its nonuniformity across a wafer, the growth rate, the film thickness nonuniformity across a wafer, and the Si/N incorporation ratio of low pressure chemical vapor(More)
Several microsystem applications require hermetic or semi- hermetic packages. It is for this reason mandatory to be able to check the hermeticity of these packages. The standard tests, using gross leak and fine leak, work very well for large cavities, but might give erroneous results for small cavities as typically used for MEMS. We discussed different(More)
In this study, finite element modelling (FEM) is used to estimate the stresses induced by the package on a high precision silicon resonator. A link between the induced stresses and strains at different temperatures and the shift in the resonance frequency is presented. In order to accentuate the effects of the package on the resonance frequency of the(More)
Capacitive Micromachined Ultrasound Transducers (cMUTs) are recognized as key enablers for emerging applications of ultrasound waves in gaseous, liquid and solid-state media, from positioning/ranging to medical treatment, through actuation, levitation, drug delivery, bio-sensing. This paper presents an improved consistent model for cMUTs implementing(More)
This paper reviews various approaches to package MEMS, illustrated mainly with examples from imec. Wafer-level or 0-level packaging is mostly dealt with. The role the package plays in achieving the required performance and reliability characteristics is elucidated. Package requirements, such as herme-ticity and strength, are named, discussed and illustrated(More)
This paper investigates the nonlinear effects introduced by the intermolecular forces on the static and harmonic behavior of electrostatically transduced nano-electromechanical (NEM) resonators using a lumped parameter model. We compute the pull-in parameters and study the full impact of the intermolecular forces on the spring softening effect, computing(More)
In the past years, the RF-MEMS activities have focused on the development of generic technology platforms integrating switches as well as tunable and fixed passives components. This is in strict opposition to a former device-centered development of the RF-MEMS technologies. Fruitful efforts were put at IMEC in the reliability analysis and modeling of the(More)
The goal of this research is to design and fabricate a very sensitive MEMS-based magnetic field sensor for space applications. The challenge is to reach the required sensitivity: measuring magnetic fields from a few nT to about 60000nT with sub-nano Tesla accuracy. The device studied in this paper is based on a classical resonating Xylophone Bar(More)