Limoges, France
Limoges, France

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Grigoriev Y.G.,Federal Medical Biophysical Center | Grigoriev O.A.,Federal Medical Biophysical Center | Ivanov A.A.,Federal Medical Biophysical Center | Lyaginskaya A.M.,Federal Medical Biophysical Center | And 7 more authors.
Bioelectromagnetics | Year: 2010

This paper presents the results of a replication study performed to investigate earlier Soviet studies conducted between 1974 and 1991 that showed immunological and reproductive effects of long-term low-level exposure of rats to radiofrequency (RF) electromagnetic fields. The early studies were used, in part, for developing exposure standards for the USSR population and thus it was necessary to confirm the Russian findings. In the present study, the conditions of RF exposure were made as similar as possible to those in the earlier experiments: Wistar rats were exposed in the far field to 2450 MHz continuous wave RF fields with an incident power density in the cages of 5 W/m2 for 7 h/day, 5 days/week for a total of 30 days, resulting in a whole-body SAR of 0.16 W/kg. Effects of the exposure on immunological parameters in the brain and liver of rats were evaluated using the complement fixation test (CFT), as in the original studies, and an additional test, the more modern ELISA test. Our results, using CFT and ELISA, partly confirmed the findings of the early studies and indicated possible effects from non-thermal RF exposure on autoimmune processes. The RF exposure resulted in minor increases in formation of antibodies in brain tissue extract and the exposure did not appear to be pathological. In addition, a study was conducted to replicate a previous Soviet study on effects from the injection of blood serum from RF-exposed rats on pregnancy and foetal and offspring development of rats, using a similar animal model and protocol. Our results showed the same general trends as the earlier study, suggesting possible adverse effects of the blood serum from exposed rats on pregnancy and foetal development of intact rats, however, application of these results in developing exposure standards is limited. Copyright © 2010 Wiley-Liss, Inc.


Andrieu G.,Xlim Laboratory | Panh J.,French National Center for Space Studies | Reineix A.,Xlim Laboratory | Pelissou P.,Airbus | And 3 more authors.
IEEE Transactions on Electromagnetic Compatibility | Year: 2012

A simple method permitting to obtain a homogeneous panel from a strongly inhomogeneous panel is presented. The method consists of determining the characteristics of a panel having an equivalent conductivity obtained from a near-field magnetic shielding effectiveness measurement. Thus, the method suitable for frequencies lower than 1MHz does not require the knowledge of the detailed internal geometry of the sample. After the validation of the measurement setup on a copper plate of known conductivity, two space composite panels are characterized and homogenized. © 2012 IEEE.


Demenitroux W.,AMCAD Engineering | Maziere C.,AMCAD Engineering | Gatard E.,AMCAD Engineering | Dellier S.,AMCAD Engineering | And 2 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2012

This paper presents a complete validation of the new behavioral model called the multiharmonic Volterra (MHV) model for designing wideband and highly efficient power amplifiers with packaged transistors in computer-aided design (CAD) software. The proposed model topology is based on the principle of the harmonic superposition introduced by the Agilent X-parameters, which is combined with the dynamic Volterra theory to give an MHV model that can handle short-term memory effects. The MHV models of 10-and 100-W packaged GaN transistors have been extracted from time-domain load-pull measurements under continuous wave and pulsed modes, respectively. Both MHV models have been implemented into CAD software to design 10-and 85-W power amplifiers in L-and S-bands. Finally, the first power amplifier exhibited mean measured values of 10-W output power and 65% power-added efficiency over 36% bandwidth centered at 2.2 GHz, while the second one exhibited 85-W output power and 65% drain efficiency over 50% bandwidth centered at 1.6 GHz. © 2012 IEEE.


Adardour A.,XLIM Laboratory | Andrieu G.,XLIM Laboratory | Reineix A.,XLIM Laboratory
IEEE International Symposium on Electromagnetic Compatibility | Year: 2013

An original method allowing to define from measurements a specific frequency called 'Quasi-Ideal Reverberation Chamber Minimal Frequency' (QIRCMF) is presented. The QIRCMF corresponds to the frequency where a mode stirred reverberation chamber is considered as working in a 'quasi-ideal regime'. After a definition of what means 'quasi-ideal' reverberation chamber, the method is presented. The method is based on 1) the assessment of the electromagnetic field distributions obtained in the working volume (in comparison with the distributions obtained in the ideal model defined in [1]) and 2) the assessment of the correlation of the electromagnetic field over one mode stirrer revolution. Experimental results clearly show that the QIRCMF can be highly reduced by introducing in the mode stirred reverberation chamber but far from the working volume a little amount of loading. © 2013 IEEE.


Adardour A.,Xlim Laboratory | Andrieu G.,Xlim Laboratory | Reineix A.,Xlim Laboratory
IEEE Transactions on Electromagnetic Compatibility | Year: 2014

An original method allowing to define a particular frequency called 'quasi-ideal reverberation chamber (RC) minimum frequency' is presented. This frequency corresponds to the frequency where an RC is considered as working in a 'quasi-ideal regime.' According to the definition of an ideal RC, the method is based on the assessment 1) of the electromagnetic (EM) field distributions obtained in the working volume (in comparison with the distributions obtained in the ideal model defined by Hill [D. A. Hill, 'Plane wave integral representation for fields in reverberation chambers,' IEEE Trans. Electromagn. Compat., vol. 40, no. 3, pp. 209 -217, Aug. 1998.]) and 2) of the number of uncorrelated samples obtained over one mode stirrer revolution. The method is considered as helpful in order to optimize the functioning of an RC at low frequencies for broadband EM compatibility immunity and emission tests. Indeed, it is shown from experimental and numerical results that the insertion of an optimal loading in the chamber allows to decrease the frequency where the chamber works quasi-ideally. The influence of complexifying the mode stirrer geometry is also discussed. © 1964-2012 IEEE.


Huitema L.,XLIM Laboratory | Reveyrand T.,XLIM Laboratory | Mattei J.-L.,LabSticc Laboratory | Arnaud E.,XLIM Laboratory | And 2 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2013

This paper presents an ultracompact antenna design suited for digital video broadcasting-handheld (DVB-H) reception devices. The DVB-H frequency band is ranging from 4 70 to 862 MHz and divided in 49 channels of 8 MHz. Designed to be integrated in a tablet, it is not only heavily miniaturized (λ0 /49 × λ0/71 × λ0/160 at 470 MHz), but also able to cover each channel thanks to the use of a magneto-dielectric material. The advantage of using such a material is studied and described in this paper. Moreover, the operating frequency is continuously tuned over the whole DVB-H band by the integration of a varactor diode. This varactor diode has been characterized and modeled to properly cosimulate its behavior within the antenna. Limitations in terms of accepted power by the diode are emphasizing. Finally, the antenna design, including both magneto-dielectric material and varactor diode is integrated in the DVB-H receiver device. Measurement performances are presented and discussed. © 1963-2012 IEEE.


Andrieu G.,XLIM Laboratory | Reineix A.,XLIM Laboratory
IEEE Transactions on Electromagnetic Compatibility | Year: 2013

The equivalent cable bundle method (ECBM), able to highly reduce the complexity of complex cable networks in numerical modeling, is applied in this paper to cable bundles in the presence of complex ground structures. In this case, a fictitious perfectly conducting ground plane is considered instead the real ground structure during the ECBM process. The use of the ECBM method appears as a relevant solution for the modeling of real industrial cable networks when the multiconductor transmission line theory is not applicable and full-wave modelings of the nonsimplified cable networks are not possible for computation time reasons. © 1964-2012 IEEE.


Adardour A.,XLIM Laboratory | Andrieu G.,XLIM Laboratory | Reineix A.,XLIM Laboratory
IEEE International Symposium on Electromagnetic Compatibility | Year: 2012

In this paper, a method for extracting and quantifying the weight of cavity modes within a reverberation chamber (RC) in the presence of different stirrers is presented from simulations performed with the FEKO software. The presented results clearly show the relationship between the efficiency of stirring and the stirred volume. © 2012 IEEE.


Moustafa L.,Xlim Laboratory | Jecko B.,Xlim Laboratory
IEEE Antennas and Wireless Propagation Letters | Year: 2010

We have shown in previous works that the use of double-layer frequency selective surface (FSS) in the superstrate of an electromagnetic band-gap (EBG) antenna provides a radiation bandwidth improvement. Nevertheless, such an antenna is still not directive enough for some applications. To increase its gain, the antenna will be fed using the multisource feeding technique. This principle is applied to design a wideband highly directive antenna operating in the Ku-band. When the radiation bandwidth corresponding to the realized gain is equal to 14% for a maximal gain of 22.5 dB, 17% of radiation bandwidth is obtained for a maximal directivity of 23 dB. © 2006 IEEE.


Huitema L.,XLIM Laboratory | Koubeissi M.,XLIM Laboratory | Mouhamadou M.,XLIM Laboratory | Arnaud E.,XLIM Laboratory | And 2 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2011

A compact multiband antenna system using a dielectric resonator antenna (DRA) is presented in this paper. Designed to be integrated in a tablet, it is not only heavily miniaturized (λ0/15×λ 0/38×λ0/94 at 800 MHz), but also able to cover three frequency bands for different wireless applications (DVB-H, WiFi and WiMAX). Since a reconfigurable radiation pattern can result in an improved quality and reliability of wireless links, two DRAs have been integrated to implement this feature on the three frequency bands. These improvements are demonstrated by the presentation of the correlation coefficient and the effective diversity gain, both measured in a reverberation chamber. The experimental measurements are in very good agreement with the simulated ones. Good overall performances are obtained, and the requirements of all three applications are perfectly met. Moreover, the antenna operative frequencies are independent of the ground plane dimensions, making this system a very good candidate for all kinds of mobile devices. © 2011 IEEE.

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