Highly integrated Active Dual Response Filter

International audienceThis work focuses on the design of a novel compact Active Dual Response Filter within a single device which allows ensuring the coexistence of three different standards while proposing an optimal structure in terms of response and space. The proposed filter is based on a highly selective low-pass filter at which a highly integrated compact notch filter is coupled. This co-integration of both filters is not a cascade so that the dual response filter occupies the same area as the low-pass filter alone. The Notch filter is set to 700 MHz and is loaded by an Active Capacitor (AC) circuit that allows a rejection at the notch central frequency of at least 19 dB. The low-pass filter cut-off frequency is Fc =890 MHz, the in band return loss is better than 20 dB. This methodology can be extended to various shapes of filter functions

FILTRE RECONFIGURABLE, COMMUTABLE ET DESACTIVABLE

L'invention concerne un filtre reconfigurable, commutable et désactivable comprenant une entrée de filtre (A) et une sortie de filtre (B) reliées par une voie directe VD, le filtre est caractérisé en ce que la voie directe (VD) est couplée (LC) à un premier résonateur (24) et un deuxième résonateur (25), chaque extrémité du premier résonateur (24) et du deuxième résonateur (25) étant connectées à une impédance de charge, ledit filtre comprend trois moyens de configuration (diode PIN Pl, P2 et P3) dont un moyen de configuration est positionné au milieu de la voie directe et les deux autres moyens de configuration après chaque ligne couplée (LC) dans le premier résonateur (24) et le deuxième résonateur (25), le filtre comprend trois entrées de reconfiguration pour chaque moyen de configuration

A Survey of Frameworks & Open Environments Applied To Cognitive Radio Design

International audienceIn modern societies, spectrum bands become very expensive and highly requested resources. Many applications based on wireless communications require smart collaboration and wise sharing of available resources. To achieve this goal, concepts of cognitive radio have been recently formulated. Even though, these systems are newly proposed, many researchers are becoming enthusiastically involved in the development of such concepts and implanting them in communication devices. In addition, several recent IEEE wireless communication standards are proposed. Major software environment, framework and cognitive radio concepts are discussed in this manuscript

Déphaseur 360 ° compact large-bande

National audienceCet article présente un déphaseur analogique 0-360 ° à variation continue de phase dans la bande 6,7 GHz - 7,7 GHz. La variation en phase est assurée par des varactors. La topologie de la cellule élémentaire est particulièrement simple et compacte. Les 360 ° sont atteints avec seulement deux cellules avec un minimum de composants pour assurer la polarisation. Le démonstrateur hybride présente des pertes d'insertion de 2,9 dB +- 1,3 dB, une adaptation meilleure que 9,4 dB, un déphasage différentiel de platitude +- 11 ° et un Facteur de Mérite de 90,5 °/ dB

Miniature Antenna for Breast Tumor Detection

International audienceMicrowave imaging is recognized as a potential candidate for biomedical applications, such as breast cancer detection. In this context a miniature antenna is used for quantitative imaging of inhomogeneous tissues. Microwave breast imaging (MBI) uses low power and longer wavelength signals to obtain information about breast tissues, and promises a safer and more accurate modality for regular breast scanning. This paper presents a miniature microstrip antenna that can be placed in contact with the breast model to investigate the presence of malignant tissues. A miniature antenna has been designed, and placed toward a breast phantom model with inhomogeneous tissues. Images are successfully obtained by using scattering electromagnetic waves (S11) from the designed model. The antenna was then manufactured and tested.In this paper the design of a miniature antenna for microwave imaging has been presented. This antenna aims to overcome the limitation of the conventional solutions by detecting breast tumors regardless its evolution stages. The simulation results show that the response of the antenna is affected in terms of frequency and return loss when it’s implanted on the heterogeneous model. Indeed, comparing to the normal breast model simulated response, the frequency was down shifted of around 100 MHz and the S11 parameter was improved. The antenna has been fabricated using plexyglass substrate and the measured results confirm the resonance frequency shift from 2.63 GHz to 2.54 GHz and the S11 improvement from -12 dB to -18 dB These results are respectively obtained when the antenna is implemented on two different mediums: clean serum representing a human body with absence of tumor and serum with steel balls representing human body with presence of tumor. After this first proof-of-concept, it’s intended to design the antenna using a flexible substrate and to perform real tests using samples representing tumors in human body which would be given by the research team of CHRU (Centre Hospitalier Régional et Universitaire de Brest) in Brest - France.

Highly integrated Active Dual Response Filter

International audienceno abstrac

Wideband High Dynamic Range Surveillance

International audienceIn recent radio-communication applications, receivers may be jammed by high power unwanted signals. In this case, the received signal can be considered as the sum of a strong unwanted signal and a very weak target signal. Even though the two signals don’t overlap in the frequency domain, the processing of the weak signal becomes very hard as it can be vanished at the output of the Analog Digital Convertor. To avoid this scenario, many nonlinear circuits are proposed in the literature. Our study focuses on the separation of a weak and a very strong signals which are wideband signals and they are very close in the frequency domain. Several circuits have been implemented and simulated. The proposed circuit diagram is also presented. Finally, simulations are presented and discussed