68 research outputs found
Design, realization and measurements of a miniature antenna for implantable wireless communication systems
The design procedure, realization and measurements of an implantable radiator for telemetry applications are presented. First, free space analysis allows the choice of the antenna typology with reduced computation time. Subsequently the antenna, inserted in a body phantom, is designed to take into account all the necessary electronic components, power supply and bio-compatible insulation so as to realize a complete implantable device. The conformal design has suitable dimensions for subcutaneous implantation (10 x 32.1 mm). The effect of different body phantoms is discussed. The radiator works in both the Medical Device Radiocommunication Service (MedRadio, 401-406 MHz) and the Industrial, Scientific and Medical (ISM, 2.4-2.5 GHz) bands. Simulated maximum gains attain and -28.8 and -18.5 dBi in the two desired frequency ranges, respectively, when the radiator is implanted subcutaneously in a homogenous cylindrical body phantom (80 x 110 mm) with muscle equivalent dielectric properties. Three antennas are realized and characterized in order to improve simulation calibration, electromagnetic performance, and to validate the repeatability of the manufacturing process. Measurements are also presented and a good correspondence with theoretical predictions is registered
MRI thermometry in phantoms by use of the proton resonance frequency shift method: application to interstitial laser thermotherapy
Unravelling the complexity of domestication:A case study using morphometrics and ancient DNA analyses of archaeological pigs from Romania
Funding statement. This work was supported by the Natural Environment Research Council (NE/F003382/1) and the Leverhulme Trust (F/00 128/AX) Acknowledgements. Archaeozoological analyses conducted by A. BaËlaËsžescu were supported by three grants from the Romanian National Authority for Scientific Research, CNCS UEFISCDI (PN-II-RU-TE-20113-0146, PN-II-ID-PCE-2011-3-0982 and PN-IIID-PCE-2011-3-1015). We thank the archeologists CaËtaËlin Bem, Alexandru Dragoman, Valentin Dumitrasžcu, Laura Dietrich, Raluca KogaËlniceanu, Cristian Micu, StaËnica Pandrea, Valentin Parnic, George Trohani, Valentina Voinea for the material they generously provided. We thank the many institutions and individuals that provided sample material and access to collections, especially the curators of the Museum fušr Naturkunde, Berlin; MuseÂŽum National dâHistoire Naturelle, Paris; MuseÂŽum dâHistoire Naturelle, Gene`ve; Museum fušr Haustierkunde, Halle; National Museum of Natural History, Washington; The Field Museum, Chicago and The American Museum of Natural History, New York; The Naturhistorisches Museum, BernPeer reviewedPublisher PD
Linear array arrangement for microwave tomography
Recent developments both in measurement techniques and reconstruction algorithms have shown the possibility of quasi-real time microwave tomography. These technical developments always require more sophisticated experimental arrangements in order to reduce the microwave circuits complexity, decrease the measurement time, and improve the resolution. This paper deals with the use of crossed linear arrays convenient for tomography by transmission. Numerical simulations and initial experimental results show the relative advantages of such arrangements as compared to the more classical two-dimensional arrays.Peer Reviewe
Early bifrontal lesions and development. From childhood into adulthood: A paradigmatic clinical video-report
Sensitivity analysis for wireless dielectric reflectometry with modulated scatterers
International audienceLoad-modulated scattering antenna technology has been very efficiently developed these last decades. Low-cost RFID tags for identification and low-invasive Modulated Scattered Technique (MST) probes for EM field measurements constitute two relevant examples. More recently, remote sensing applications of modulated scatterers have been considered. In such applications, the general objective is to remotely retrieve some local property of a material or environment under test via its impact on a modulated scattering probe. This paper is more particularly focused on the case where the sensing mechanism is expected to result from the change of the probe impedance, due to variations of the refractive index in its close vicinity. This problem is usually addressed under empirical and global viewpoints, by combining numerical modeling and optimization. Often, such a blind approach may result in some disappointment. This paper aims to develop a more comprehensive analytical-based approach, thanks to a general reciprocity-based formulation. Inspired from standard reflectometer techniques, the ternary load modulation scheme is shown to remove specific difficulties inherent to wireless reflectometry such as propagation effects or misalignment between the probe and the reader antennas. The test case of center-loaded dipoles is considered for the sake of illustration
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