Mohamad Hajj

Metallic EBG sectoral antenna for base stations

This work aims to study and design antennas for base stations containing metallic electromagnetic band gap (EBG) materials. The objective was to make and study new concepts of EBG metallic antennas able to work according to a wide (or broad) form pattern radiation, i.e. presenting at least 60deg angular aperture. The use of metallic structures offers a new approach to the industrial partners to reduce the costs and to facilitate the design techniques. The high impedance presented by the metallic structure allows us to use only one layer of rods and to make the antenna less cumbersome than it was before with a dielectric structure.

Design of Sectoral Antennas Using a Metallic EBG Structure and Multiple Sources Feeding for Base Station Applications

This work aims to study and design base station antennas with metallic electromagnetic band gap (EBG) materials able to create a sectoral radiation pattern presenting at least a 60∘ beamwidth. The use of metallic structures offers a new approach to industrial partners seeking to reduce costs and facilitate design procedures. A new method allowing the improvement of both the directivity and the bandwidth by using a printed antenna array is studied.

Multibeam Antenna for Telecommunications Networks Using Cylindrical EBG Structure

We present in this letter the study of a multibeam antenna for telecommunication networks by using cylindrical electromagnetic band-gap (EBG) structures. The EBG structure behaves as a partially reflecting surface (PRS) and enhances the directivity of a simple radiating source. We begin by presenting the principle of the multibeam antenna, and then we present a first version, conceived to operate in WiMAX band [5.45.7] GHz. Simulation results of this antenna will show us that the strong mutual coupling between the different excitation sources of the EBG structure badly influences its performance. In order to reduce the mutual coupling, metallic walls are inserted between the excitation sources. Moreover, excitation sources have been changed to improve the radiation performance of the antenna. A prototype of the final antenna is fabricated to validate our simulation results, and the measurements results are compared to the simulated ones.

Multifed Sectoral EBG Antenna for WiMAX Applications

Sectoral antennas are used for applications that do not need symmetric patterns in vertical and horizontal planes. This letter deals specifically with sectoral electromagnetic band-gap (EBG) antennas and focuses on the ability to obtain higher gain and better performances. First, we start with a brief description of the working principle of such antennas. Then, we propose an original model of sectoral EBG antenna based on Babinet theorem. The multisource feeding technique is used in the antenna design in order to achieve higher performances. Finally, a prototype of this model is realized, and an extensive set of measurement and simulation results are reported and discussed.

A Novel Beam Scanning/Directivity Reconfigurable M-EBG Antenna Array

In this paper, we introduce a new technique for an electronic beam scanning/directivity reconflgurable which can be carried out by using a joint array of Metallic Electromagnetic Band Gap (M-EBG) sectoral antennas. This study opens new avenues of research on M-EBG sectoral antennas by combining multiple radiating elements in an array. Usually M-EBG structures are designed in passive conflgurations to radiate flxed/shaped beams thanks to a speciflc radiating aperture at the surface of the M-EBG antenna. However by opting this new technique, we are able to control the radiating aperture, and therefore provide a tunable directivity/beam pattern. The objective of the paper is to propose a solution for M- EBG antennas in order to achieve Beam Scanning and Directivity reconflgurability. The main advantage of the proposed technique is that the array have negligible mutual coupling between the radiating elements, simplifying therefore the conception of the beam-forming network and the problems of constrained beam scanning. Another objective of the paper is to be able to achieve wide angle beam scanning i= + 58 degrees. This method makes it possible to obtain in a simple way an agile M-EBG antenna without the need of the expensive active electronic components. Several results show the efiectiveness and the capabilities of the proposed technique.

New Development Around M-PRS Antennas for Sectoral Coverage of Telecommunication Networks With Dual Polarization

In this letter, we present a novel approach to study and design a dual-polarized sectoral antenna using a double layer of metallic partially reflecting surface (M-PRS) working on orthogonal polarizations as a superstrate. The use of metallic structures offers a new approach to industrial partners in order to reduce costs and to facilitate design techniques. This antenna is able to radiate in vertical, horizontal, and dual polarization with a wide (or broad) radiation pattern form, i.e., presenting at least 60deg angular beamwidth in the azimuth plane. M-PRS antennas with sectoral pattern are usually designed only for vertical and horizontal polarization. A dual-polarized sectoral M-PRS antenna for lower Hiperlan2 application [5.155.35] GHz is presented.

EBG antenna conformation for beamforming

Conformal antennas design is a new approach of interest to those in radar and communication systems and antenna engineers, creating antennas having any desired pattern radiation which is determined by considerations like the type of the zone to be covered, urban or rural. This paper provides a fundamental understanding of the characteristics of EBG (electromagnetic band-gap) conformal antennas; we have considered planar metallic EBG structures and studied the role of electrical walls and their influence on electromagnetic radiation. An example of the conformal antennas, the sectoral ones, are presented. Then we showed a simulated metallic sectoral EBG antenna for WiMAX application. Finally, we presented a method for antenna beamforming using diodes, starting with a square one.

Dual-band metallic FSS-EBG sectoral antenna

In this paper we present a novel approach to create a dual frequency band of a new sectoral antenna design combining metallic EBG materials as a superstrate with a frequency selective surfaces (FSS) as a substrate. The geometry and working of the antenna are detailed and a design method is proposed.

2D Matrix of joint ultra low-profile (ULP) EBG antennas for high gain applications

This article presents the design of a 2D Matrix composed by Joint ULP EBG antennas for High Gain Applications. The advantage of this solution is the low coupling levels between each radiating element (ULP EBG antenna). This structure can also be used to make shaping beam.

A novel design of circularly polarized sectoral M-PRS antenna

A novel circularly polarized sectoral antenna on a Metallic Partially Reflective Surface (M-PRS) for wireless application within [5.15–5.35] GHz is proposed. By using double layers of M-PRS working on orthogonal polarizations as a superstrate with a single patch feeding by two ports, circular polarization is achieved. This antenna provides two perpendicular polarizations, vertical and horizontal, circular with a sectoral radiation pattern in the azimuth plane. The details of simulation results for the proposed design are presented and discussed.