AS Nijmegen, Netherlands
AS Nijmegen, Netherlands
Time filter
Source Type

Lai J.C.Y.,Nanyang Technological University | Xu Y.,TDK EPC | Gunawan E.,Nanyang Technological University | Chua E.C.-P.,National University of Singapore | And 5 more authors.
IEEE Transactions on Instrumentation and Measurement | Year: 2011

The simultaneous tracking of the chest respiratory rate and amplitude of human beings using a low-power ultrawideband (UWB) impulse radio signal is investigated for the application of sleep apnea monitoring. The measurement of respiratory amplitude, in addition to the breathing rate, is crucial for sleep apnea assessment which requires, among other things, the accurate estimation of tidal volume per minute. Backscattered UWB impulse radio signals from a human subject are detected in the time domain to calculate the chest displacements in this paper. Since the pulse disposition in time is linearly related to the chest movement, the amplitude of the chest movement can be extracted accurately without calculation approximations normally used in many of the existing methods. The multipeak detection of the pulse disposition method, instead of using only the single pulse peak detection, is also proposed to improve the accuracy of the calculation further. The experiments are carried out on four human subjects with different sizes and genders. The correlation of the chest movements' amplitude and breathing rate between the simultaneously measured results obtained by our method and by the respiratory chest band is very good. © 2006 IEEE.

Bermejo R.,University of Leoben | Supancic P.,University of Leoben | Supancic P.,Materials Center Leoben Forschung | Aldrian F.,TDK EPC | And 2 more authors.
Scripta Materialia | Year: 2012

An experimental approach is proposed, based on localized biaxial testing of brittle samples at several locations under different environments, to quantify the effect of surface features or metallization (e.g. contacting pads or cylindrical vias) on the strength distribution of functional ceramic components. It is found that cylindrical vias can act as weak points in the design (i.e. lower strength and reliability), whereas contacting pads can raise the strength of the component acting as a protective layer against environmental degradation. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Savelsberg R.,Netherlands Defence Academy | Schiffer M.,TDK EPC | Obermeier E.,TU Berlin | Castro I.P.,University of Southampton
Experiments in Fluids | Year: 2012

Microelectromechanical systems (MEMS) sensors are increasingly used for measurements in fluid dynamics since, because of their inherently compact size, they allow access to the information that was previously unavailable. In this paper we describe further testing of a MEMS sensor used to measure surface shear stress. It is awall-mounted fence that bends under the influence of the pressure difference resulting from the velocity shear at the wall. The fences have been successfully calibrated in a wind tunnel and, as an example of their application, used to determine mean and fluctuating shear stress (along with spectra) in a cylindrical cavity flow. © Springer-Verlag 2012.

Karilainen A.O.,Aalto University | Ikonen P.M.T.,TDK EPC | Simovski C.R.,Aalto University | Tretyakov S.A.,Aalto University
IEEE Transactions on Antennas and Propagation | Year: 2011

We address the question of the optimal choice of loading material for antenna miniaturization. A new approach to identify the optimal loading material (dielectric or magnetic) for maximization of bandwidth of resonant antennas is introduced. Instead of equivalent resonant circuits or transmission-line resonators, we use the analysis of radiation mechanism to identify the fields contributing mostly to the stored energy and determine the beneficial material type. The formulated rule is qualitatively illustrated using a dipole and a patch antenna, as well as a planar inverted-L antenna where the conventional analysis of circuit or a transmission-line resonator leads to incorrect conclusions. Guidelines are presented for miniaturizing different antenna types. © 2011 IEEE.

Karilainen A.O.,Aalto University | Ikonen P.M.T.,TDK EPC | Simovski C.R.,Aalto University | Tretyakov S.A.,Aalto University | And 4 more authors.
IET Microwaves, Antennas and Propagation | Year: 2011

Dielectric or magneto-dielectric materials can be used to miniaturise antennas, but there are many important parameters that must be considered when selecting which material to use. The authors discuss these figures of merit and a rigorous method to compare antennas with different material fillings. A meandered planar inverted-F antenna (PIFA) loaded with magneto-dielectric and dielectric materials is presented as an example antenna for testing. The magneto-dielectric material used is composed of mylar substrate and Fe-SiO 2 sheets. Measurement results for the permeability of the material are presented. The radiation mechanism of the meandered PIFA is studied, and the proper position for dielectric and magneto-dielectric filling is discussed and identified. Miniaturisation by commercial dielectric and the presented magneto-dielectric fillings is measured and compared at the same resonance frequency using the radiation quality factor as the figure of merit. It is seen, that the antenna can benefit from the magneto-dielectric filling material in terms of the radiation quality factor only if the placement of the antenna filling is carefully selected. © 2011 The Institution of Engineering and Technology.

Laroche T.,CNRS Femto ST Institute | Ballandras S.,CNRS Femto ST Institute | Daniau W.,CNRS Femto ST Institute | Garcia J.,CNRS Femto ST Institute | And 4 more authors.
IEEE International Ultrasonics Symposium, IUS | Year: 2011

In this paper, the combining of Finite Element Analysis and Boundary Element Method is investigated to address non periodic Surface Acoustic Wave devices. The validation of this method is achieved by comparison with proofed numerical method. Preliminary computations on passivation influence are given. © 2011 IEEE.

Hagelauer A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Weigel R.,Friedrich - Alexander - University, Erlangen - Nuremberg | Link A.,TDK EPC | Bader B.,TDK EPC | And 2 more authors.
Proceedings - IEEE Ultrasonics Symposium | Year: 2010

Duplexers and filters for mobile radio are one of the classic field ofapplication for the BAW technology. In recent years the size of the devices hasbeen reduced by about a half and the trend is still toward more compact designswith higher performance at the same time. This translates directly to verydemanding requirements on the effective coupling coefficient and on the qualityfactors of the underlying BAW resonators. Measurements show that the size andthe shape of the resonators have a significant influence on the overallperformance. Hence, size-relevant effects need to be considered in1D-simulation, which is the base for fast filter optimization. To evaluate theinfluence of the resonator size on the filter performance we analyzed severalSMR-BAW resonator area and shape variations in combination with differentoverlap sizes in a series of experiments. Moreover, the influence of the overlapsize on different resonator areas is studied with 2D-FEM simulations. In thispaper we present the results of our resonator measurements. The results arebasis for developing a modified 1D-model for designing BAW filters.Additionally, a new method for the extraction of an equivalent acousticimpedance for the description of the acoustics is presented and compared to themodified 1D-model. © 2010 IEEE.

Wang W.,Friedrich - Alexander - University, Erlangen - Nuremberg | Fischer G.,Friedrich - Alexander - University, Erlangen - Nuremberg | Van Den Oever L.,Radio Semiconductor Corporation B.V. | Korden C.,TDK EPC | Weigel R.,Friedrich - Alexander - University, Erlangen - Nuremberg
2011 German Microwave Conference, GeMiC 2011 - Proceedings | Year: 2011

A tapered distributed power amplifier is designed for linear mobile phone power application, which covers the 3G mobile phone bandwidth from 800 MHz-2 GHz completely. It illustrates the opportunity of multiple power modes capability for power added efficiency (PAE) enhancement. Each power mode fulfills the WCDMA linearity specification up to a specific maximal output power. © 2011 Institut fur Mikrowellen.

De Jongh M.A.,TDK EPC | Van Bezooijen A.,TDK EPC | Boyle K.R.,TDK EPC | Bakker T.,TDK EPC
IEEE MTT-S International Microwave Symposium Digest | Year: 2011

Mobile phone output power and radiation efficiency are degraded by large mismatches, due to compact narrow-band antennas and the influence of the user's hand position. This paper presents a 5×5 mm2 multi-band multi-mode adaptive antenna tuning module that counteracts antenna impedance mismatch. The module increases phone output power by 1.2 dB on average and 10 dB maximum, once combined with four different commercially available phones in a load-pull setup. The measured average total radiated power (TRP), of one of these phones with adaptive tuner, improves by 2.2 dB for free-space condition and 1.9 dB for user interaction. The measured maximum TRP improvement is 6.8 dB. © 2011 IEEE.

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