Régis Chantalat

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.

Phase Center Study of the Electromagnetic Band Gap Antenna: Application to Reflector Antennas

Recent studies have shown that the electromagnetic band gap (EBG) antenna can be used to feed a reflector, especially to realize multibeam coverage with geostationary satellite. However, it is necessary to evaluate its performances in terms of aperture efficiency to compare this solution to the classical ones. Among all the parameters which contribute to the aperture efficiency, one of the most important is the phase center, which has never been determined for EBG antennas. This is the aim of this letter. After defining a simple method to calculate the phase center of the EBG antennas, the position and the frequency evolution of this parameter will be studied. Then, the performances of such a feed associated with a Side Fed Offset Cassegrain Antenna (SFOCA) will be evaluated and compared with a classical feed for reflector, a Potter horn

1D dielectric electromagnetic band gap (EBG) resonator antenna design

This article presents a new methodology allowing to design a planar electromagnetic band-pap antenna (choice of theebg material, sizing, feeding). This kind of antenna has already been presented.ebg antennas are very thin (compared with parabolic reflectors) high gain antennas. This article makes easier the realization ofebg antennas whatever the operating frequency, the gain, or still the bandwidth. A study about the sensitivity of the material properties on the performances is also presented. Finaly two exemples using this design method are described.RésuméCet article décrit une méthodologie complète inédite permettant de dimensionner et de réaliser une antenne planaire à bande interdite électromagnétique (Choix du matériau, de la configuration, dimensionnement, alimentation...). Le fonctionnement de ce type d’antenne a déjà été publié. Les antennesbie sont des antennes directives à encombrement réduit en épaisseur (En comparaison avec par exemple une antenne parabolique). Cet article facilite la réalisation des antennesbie quelques soient la fréquence, le gain ou encore la bande de fonctionnement. Une partie concerne également la sensibilité des éléments du matériau sur les performances de l’antenne. Enfin, deux exemples concrets utilisant cette méthode de conception sont présentés.

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.

Low Profile EBG Resonator Antennas

An Electromagnetic Band Gap (EBG) antenna is a planar structure which is composed of a cavity and an EBG material. In most applications, the height of the EBG antenna is half wavelength. We present in this paper the conditions to reduce the profile of an EBG antenna to subwavelength values. It could be achieved by using a cavity upper interface which exhibits negative reflection phase. Frequency Selective Surface (FSS) based on Babinet principle, that satisfies this condition, will be described using full wave analysis. These periodic metallic arrays are employed in the design of a low profile EBG antenna which has a directivity of 10 dBi. As this EBG antenna design is similar to a small antenna over an Artificial Magnetic Conductors (AMC) surfaces or High Impedance Surface (HIS), the EBG antenna principle could be a new theory approach for the AMC or HIS. This point is discussed in this paper.

EBG Focal Feed Improvements for Ka-Band Multibeam Space Applications

This letter presents the enhancement of an electromagnetic band-gap (EBG) antenna that is used to feed a reflector antenna for a space multibeam application in Ka band. One of the main difficulties in a typical focal feed cluster design is to obtain high illumination performances with neighbored and close radiating elements. The new structure presented in this letter tackles this difficulty by using a two-level EBG antenna as a multibeam focal feed. This last one is designed to illuminate a side-fed offset cassegrain antenna (SFOCA) working in Ka band and dedicated to a multibeam telecommunication coverage over Europe. A prototype has been measured, and the reflector antenna performances have been evaluated in order to show the good results obtained with this new multibeam focal feed.

Wide Bandwidth, High-Gain, and Low-Profile EBG Prototype for High Power Applications

In this letter, we present a wide-bandwidth, low-profile, and high-gain electromagnetic band-gap (EBG) resonator antenna that is used for high power and electronic warfare applications. It presents a bandwidth of 71% (from 1 to 2.1 GHz) and a maximum gain of 17 dB. The profile of this antenna is very low (22 mm, which is equivalent to λ/11 at 1.2 GHz). A prototype of this modeled antenna is manufactured, and the measured performances are similar to the simulated ones.

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.

Offset Parabolic Reflector Antenna Fed by EBG Dual-Band Focal Feed for Space Application

A new design of a metallic dual-band electromagnetic band-gap (EBG) suitable to feed a reflector antenna for space multibeam applications is introduced in this letter. The EBG antenna is composed of double-layer frequency selective surfaces (FSS) arranged in the longitudinal direction and a square horn as a feed. First, we devise a technique to adapt the dual-band EBG antenna characteristics for this space application, which requires the same EBG phase center and the same radiation patterns for both frequency bands. Then, a dual-band EBG antenna has been designed. Finally, a prototype is realized, and the experimental measurements are compared with success to the simulated ones. The same phase center has been obtained at 5 and 7.5 GHz. This antenna is suitable to feed a reflector antenna with a focal-length-to-diameter (F/D) ratio of 1.2. The performances of the offset reflector fed by this antenna are good with a maximum efficiency about 77% and with sidelobes levels always better than -22 dB for both frequency bands.