Majed Koubeissi

Compact and Multiband Dielectric Resonator Antenna With Pattern Diversity for Multistandard Mobile Handheld Devices

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×λ0/38×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.

Global Design of an EBG Antenna and Meander-Line Polarizer for Circular Polarization

This letter describes a comprehensive approach to design circularly polarized electromagnetic band-gap(EBG) antennas. Some solutions have already been proposed to that end, but they require the design to be started from scratch. With the proposed method, the circular polarization will be obtained through the use of a meander-line polarizer (MLP) located above an existing linearly polarized EBG antenna. Thanks to a global approach, a 20-dBi circularly polarized antenna, boasting an axial ratio (AR) lower than 1 dB over the 29.530 GHz frequency band, has been conceived, realized, and successfully measured.

Ultrawideband Dielectric Resonator Antenna for DVB-H and GSM Applications

This letter presents a novel design of compact dielectric resonator antenna (DRA) that is dedicated to ultrawideband applications such as digital video broadcasting-handheld (DVB-H). The dimensions of the radiation element are lambda0/7 times lambda0/13 times lambda0/28 at 466 MHz. A miniaturization technique has been used in order to reduce the antenna size, and a parametric analysis of the antenna is performed. The measured results agree well with the simulated ones. The proposed antenna offers a bandwidth of 70% around 700 MHz for -8 dB impedance matching bandwidth definition and covers the Ultra High Frequency (UHF) IV, V and Global System for Mobile communications (GSM) bands.

Global Synthesis Method for the Optimization of Multifeed EBG Antennas

This paper presents a novel technique for synthesizing a given radiation pattern from an EBG antenna with an array feed. The method determines the optimum sets of input waves and input impedances for the feed ports in order to perform simultaneously the radiation pattern and the impedance matching of all the radiating probes that form the array feed. The method is validated through a numerical design of an EBG antenna excited with four patch antennas. The structure is designed to radiate with a single lobe scanned at 𝜃=30∘ in the E-plane. The interactions between each patch inside the EBG resonator are characterized with the CST MWS software. The optimum weights and the input impedances which simultaneously perform the objective radiation and the matching of all feeding ports are calculated by the developed global synthesis method. The feed network is designed with the Agilent ADS software in order to perform the specified weights and the impedances matching.

Triband Compact Antenna for Multistandard Terminals and User's Hand Effect

A novel compact wideband triband antenna for mobile terminals based on PIFA element is proposed. The antenna operates at the following frequency bands: Wireless-LAN 802.11 b, g, a and WiMAX 3.5 GHz. The antenna was studied by means of numerical simulations as well as the ground plane dimensions and users hand effects. The overall size of the radiating element which is 1.8×1.54×9 mm makes it suitable for use in terminals and appropriate to integrated as an internal laptop antenna. The measured bandwidths show that the proposed antenna can cover three bands (2.39–2.48 GHz), (3.36–3.76 GHz), and (4.7–6.3 GHz) and the total efficiency is better than 90%. The radiation patterns of the antenna were carried in an anechoic chamber and are given to demonstrate the antennas performance.

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

The purpose of this letter is to offer new performance characteristics to base station antennas. The proposed antenna is developed for the European project BROADWAN framework. We propose a new switched beam antenna array based on the 5 times 8 novel Butler matrix topology which provides a cosecant squared elevation pattern. In this letter, the implementation of the beamforming network and the cosecant squared feed lines at 42 GHz are detailed and a comparison between simulated and experimental results is presented.

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

Two 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, thats why these structure are good candidates for all mobile handheld devices.

Handheld dielectric resonator antenna for ultra wideband applications

A novel design of compact dielectric resonator antenna (DRA) dedicated to ultra wideband applications such as Digital Video Broadcasting-Handheld (DVB-H) is presented in this paper. A miniaturization technique has been performed in order to reduce the antenna size. The obtained dimensions of the final design of the DRA are λ0/7 × λ0/13 × λ0/28 at 466MHz. Also, measurements are presented to validate the results obtained via simulation. The proposed antenna offers a bandwidth of 70% around 700MHz for −8dB impedance bandwidth definition and covers the Ultra High Frequency (UHF) IV, V and Global System for Mobile communications (GSM) bands. Finally a DRA using magneto-dielectric materials is presented and its performances are shown.

Multilayer switched beam antenna with cosecant-squared elevation pattern for communication systems

The purpose of this paper is to offer new performances to the base station antennas. We propose a new switched beam antenna array based on the 5 times 8 novel Butler matrix topology and providing a cosecant squared elevation pattern. In this paper, the implementation of the beamforming network and the cosecant squared feeding lines at 42 GHz are detailed and some results are presented. The antenna has been fabricated to validate our simulations and the measure process is in progress.