Emmanuel Rodes

Circularly polarized metallic EBG antenna

This letter describes the concept and the realization of a directive and circularly polarized antenna using an electromagnetic band gap material whose circular polarization is generated by the structure itself. Experimental and simulated results are presented for an antenna operating at 5GHz.

Dual-Band EBG Resonator Antenna Using a Single-Layer FSS

This letter presents a new design for electromagnetic bandgap (EBG) resonator antennas allowing to create dual-band structures, thus, making it possible to circumvent the problem of their narrow bandwidth. The geometry and working of the antenna are detailed and a design method is proposed. Both the concept and the method are validated by experimental results.

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.

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.

Performance Enhancement of Self-Polarizing Metallic EBG Antennas

This letter presents an original solution to solve the matching problem of the circularly self-polarizing electromagnetic band-gap (EBG) antennas. More precisely, a comprehensive method to design a self-polarizing EBG antenna will be detailed. This kind of antenna had been designed before, but it was very poorly matched. An iris-based matching system has been used here, which produced a satisfying return loss while deteriorating the axial ratio (AR). An original device will be introduced, which allowed us to compensate for this degradation. Finally, to validate this new structure, a 20-dBi antenna working around 9 GHz and showing an AR lower than 1 dB over a 100-MHz bandwidth has been conceived, realized, and successfully measured.

Steerable and tunable "EBG resonator antennas" using smart metamaterials

The properties of the antenna depend on three structural parameters: the thickness separating the two parallel mirrors, the complex reflectivity of the partially reflective mirror and the radiation of the probes that are distributed between the two mirrors. This shows that a coordinated action on these parameters can lead to a smart EBG antenna. The design of one of the two mirrors constituting the EBG resonator with a smart metamaterial allowing the control of the reflectivity is the key to obtain both a tunable operating frequency and the beam steering adjustment. We show how the feeding antenna can be used to contribute to the beam steering. So we explore the possibility to build smart metamaterials including MEMS or diodes

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.

Design of a dual-band EBG resonator antenna using capacitive FSS

This paper presents a new design for EBG resonator antennas allowing to create dual-band antennas, thus making it possible for some applications to circumvent the problem of their narrow bandwidth. The design and the conception method are detailed and one application example is given

On the Use of Metamaterial Surfaces for EBG Antenna Improvements

This paper presents several configurations where frequency selective surfaces are used to improve EBG resonator antennas performances. The different detailed structures are mainly focused on the bandwidth limitation of these antennas which has been addressed in various ways. In addition to a wide band antenna, two structures showing a dual band functioning are presented, of which one moreover possesses some frequency agility. The building of several prototypes and their measurement has confirmed the promising theoretical results.