DUAL-BAND PRINTED DIPOLE ANTENNA ARRAY FOR AN EMERGENCY RESCUE SYSTEM BASED ON CELLULAR-PHONE LOCALIZATION

International audienceThis paper describes the study of a novel dual-band antenna dedicated to be mounted on a helicopter for emergency localisation of cellular phones within the framework of the RNRT project called LUTECE. A folded dipole placed on a limited ground plane to allow wideband functionality and good radiation characteristics is proposed. Starting from this new topology, a directive array for the emission part and a circular disposition of five radiating elements with separated outputs for the receiving part are studied. All these developments are performed using our simulation code (FDTD method) along with experimental studies

Chip antenna utilisant un materiau magneto dielectrique fonctionnant dans la bande uhf v

National audienceFace à la miniaturisation et devant la volonté d'intégrer un nombre toujours plus important de nouvelles applications au sein d'un même terminal mobile, la diminution de la taille de l'antenne devient un enjeu important. Les dimensions de l'antenne étant inversement proportionnelles à , la diminution de la taille de l'antenne passe généralement par l'utilisation de matériaux purement diélectriques à forte permittivité [1], ceci au détriment des performances de l'antenne notamment de sa bande passante [2]. Cependant, la bande passante, peut être améliorée par l'utilisation de matériaux associant une perméabilité magnétique à une permittivité diélectrique [3, 4]. L'objectif de notre travail est de montrer que l'utilisation de tels matériaux magnéto-diélectriques permet de remédier à cette réduction de bande passante dans le cas d'une chip antenna. Dans ce cadre, une antenne intégrant un matériau magnétodiélectrique est présentée. Une première partie sera consacrée à la description du matériau utilisé. Une seconde partie montrera la structure de l'antenne tout en mettant en évidence l'avantage d'utiliser un matériau magnéto diélectrique. Nous présenterons et discuterons des résultats obtenus en simulation

Dual-Band EBG Sectoral Antenna Using a Single-Layer FSS for UMTS Application

International audienc

"A 45° Linearly Polarized Sectoral Antenna with M-EBG Structure for WIMAX Base Stations"

International audienc

Overview of two ultra compact antennas using original materials with pattern diversity

International audienceTwo designs of compact antennas dedicated to different wireless applications are presented in this paper. For both, to improve the quality of the wireless link, two radiating elements have been orthogonally integrated to apply diversity techniques. These diversity performances will be underscored by the presentation of the effective diversity gain, measured in a reverberation chamber. The first design is using a high permittivity material and combining Dielectric Resonator Antenna (DRA) resonances with a quarter-wavelength resonance of a monopole judiciously optimized to feed and set dielectric resonator modes. Finally it covers nine channels of the DVB-H band going from 790 MHz to 862 MHz, the WiFi band at 2.4 GHz and the WiMax band at 3.5 GHz and the dimensions of each radiating element are very small (λ0/15 × λ0/38 × λ0/94 at 800 MHz). The second design uses a magneto-dielectric material, it focuses on the nine channels of the DVB-H band covered by the first design. The dimensions of each radiating element are lower than the first one since the dimensions are λ0/25 × λ0/38 × λ0/95 at 800 MHz. Good performances and very good agreement between measurements and simulations have been obtained since return losses, efficiencies and realized gains are suitable and meet all applications requirements for both designs. Moreover, the operation bands are independent from the ground plane dimensions, that's why these structure are good candidates for all mobile handheld devices

Design of a Cosecant-Squared Pattern Antenna Fed by a New Butler Matrix Topology for Base Station at 42 GHz

International audienc

Mise au point d'antennes à éléments parasites large bande à polarisation circulaire

National audienc

Reflectarray antennas with accurate calculation of phase shifts

International audienceThis article presents a new approach to analyze a reflectarray antenna and calculate the phase shifts needed to generate a beam in a given direction. The method is used with a two layer reflectarray including local ports. Reactive loads on the rear panel allow a beam control. The method described combine full-wave simulation and analytical formulation to obtain both accuracy and versatility

Systematic Design of Parasitic Element Antennas - Application to a WLAN Yagi design

International audienc

Design Method of EBG Structure with Wide defect Band

International audienc