Phased array antenna with significant reduction of active controls

192 Pages·2016·4.71 MB·English

by  Francesco Scattone

ANNÉE 2015
THÈSE / UNIVERSITÉ DE RENNES 1
sous le sceau de l’Université Européenne de Bretagne
pour le grade de
DOCTEUR DE L’UNIVERSITÉ DE RENNES 1
Mention : Traitement du Signal et Télécommunications
Ecole doctorale MATISSE
présentée par
Francesco SCATTONE
préparée à l’unité de recherche UMR 6164 - I.E.T.R
Institut d’Électronique et de Télécommunications de Rennes
UFR Informatique - Électronique
Thèse soutenue à Rennes
le 15 décembre 2015
Phased array antenna devant le jury composé de :
Thierry MONEDIERE
with significant Professeur, XLIM, Limoges/rapporteur
Xavier BEGAUD
Professeur, LTCI, Paris/rapporteur
reduction
Hélène ROUSSEL
Professeur, LE2, Paris/examinateur
of active controls
Shah Nawaz BUROKUR
Maître de conférences, IEF, Paris/examinateur
Giovanni TOSO
Docteur,ESA,Noordwijk,Pays-Bas/membreinvité
Benjamin FUCHS
Chercheur CNRS, IETR, Rennes/membre invité
Mauro ETTORRE
ChercheurCNRS,IETR,Rennes/directeurdethèse
Ronan SAULEAU
Professeur, IETR, Rennes / co-directeur de thèse
Nelson FONSECA
Docteur,ESA,Noordwijk,Pays-Bas/co-directeurde
thèse

L’auteur, les encadrants, le laboratoire et ses tutelles tiennent a` remercier le Conseil
R´egionaldeBretagnepourl’attributiond’uneallocationderecherchedoctorale(ARED,
campagne 2012) ainsi que l’Agence Spatiale Europ´eenne pour son soutien scientifique,
technique et financier.

A mio nonno
v

Acknowledgments
MyPh.D.workwouldhaveneverbeenpossiblewithoutthecontributionandthesupport
of the people I met in IETR and ESA-ESTEC and I would like to express my gratitude
to them.
First of all, I would like to thank my supervisor Mauro Ettorre for the time he spent
teaching me most of the thing I needed and I will need during my future career. Grazie
Mauro.
I would like to thank Prof. Ronan Sauleau, my co-supervisor in IETR, for his precious
support during the years I spent in IETR.
I would express my gratitude to Nelson Fonseca, my co-supervisor in ESA-ESTEC, for
working close with me during the three years of Ph.D. and for letting me enjoy my stay
in The Netherlands.
IwishtoacknoledgeProf. ThierryMonediereandXavierBegaudforcarefullyreviewing
this manuscript and Prof. H´el`ene Roussel, Prof. Shah Nawaz Burokur, Giovanni Toso
and Benjamin Fuchs, for being members of the jury.
I would also thank my colleagues in IETR for the time we spent togheter, in particular
Franck, Carole, Narcisse, Fran¸cois, Laurent.
I ricordi piu` belli di questi tre anni vengono dagli amici che ho incontrato e che sono
diventati la mia famiglia durante questo periodo. In particolare vorrei ringraziare
(nell’ordineincuilihoconosciuti)Giovanni,Ana,Francesco(FFM),Giovannis,Fabrizio
’o sarracino e Ida. Tra questi non ho inserito Riccardo, poich´e in lui non ho trovato un
amico, ma un fratello.
Il mio pensiero va anche ai miei amici storici che mi hanno supportato da lontano:
Federico, Claudio, Eleonora (che mi ha supportato e sopportato), Michelle, Piero, Luca
e Andrea. Un grazie va alla mia famiglia e in particolare ai miei nonni che hanno vissuto
questamiaesperienzaconun’enfasispeciale. InfineunringraziamentovaaRosa,entrata
nella mia vita nella parte finale di questo percorso lasciando un segno indelebile.
vii

Abstract
The objective of this thesis is to exploit the leaky-wave phenomena to enhance the per-
formance of classical aperture antennas for space applications. Here, we consider planar
configurations where the leaky modes are excited between a ground plane and a par-
tially reflective superstrate, made of impedance sheets or dielectric slabs. Arrangements
of small apertures opening on the ground plane are used to feed the antennas under
study. The superstrate-like leaky-wave structures are developed in array or phased ar-
ray configurations. These solutions are considered of interest in terms of flexibility of
the system for next generation satellite links.
Inordertoefficientlystudyplanarleaky-wavearrays,wehavedevelopedananalysistool
based on a Green’s function spectral approach. The developed tool allows to precisely
analyzetheproposedstructurebytakingintoaccounttheimpactofthemutualcoupling
among the elements on the radiation performance of the whole antenna. In addition, it
can handle extremely large structures in terms of wavelengths with a small computa-
tional effort with respect to commercial tools. This tool has been used during the thesis
to efficiently analyze the main features associated to the leaky-wave phenomenon, such
as the gain enhancement and pattern shaping, for the improvement of the performance
of the classical array solutions.
In particular, the gain enhancement of leaky-based structures can be an effective way to
reduce the number of elements of the associated phased arrays. In a leaky-wave config-
uration each element of the array will radiate with a larger equivalent aperture allowing
a larger spacing among elements without affecting the final gain of the whole structure.
This aspect is particularly important in the case of phased arrays, where phase shifters
and control cells are, typically, the most expensive components of the system. As ex-
tensively explained in the manuscript, antennas for user segment might find the highest
benefit by using leaky-wave solutions. In fact, the constraints on bandwidth (1 ∼ 3%)
and periodicity (1 ∼ 2 wavelengths) make the leaky-wave technology suitable to reach
the high aperture efficiencies required for such applications.
Besides the gain enhancement, the leaky-wave technology can be effectively exploited to
conveniently shape the radiation pattern by properly engineering the design parameters
of the antenna. For superstrate-like structures, as those considered in this work, such
parameters are the reflectivity of the partial reflecting screens and their spacing. This
capability can be used in phased arrays to generate a convenient element pattern to
minimize the scan losses and filter the grating lobes appearing in the visible space when
dealing with periodicities larger than a wavelength. Therefore, a synthesis procedure
for thinned leaky-wave arrays is presented in the manuscript, showing the benefits of
the superstrate configuration. In particular, it is shown that it is possible to design
thinned arrays with a number of elements reduced by a factor 4, if compared with bare
configurations, working in a band of 7%. Also, a novel array configuration, the irregular
superstrate array, is presented. The irregular superstrate allows the reduction of the
side lobes of the antenna below −20 dB in the considered 2.5% band, using a uniform
excitation. Such solution avoids the use of complicate feeding networks of classical so-
lution. This last configuration clearly shows that the shaping capability of leaky-wave
antennas is the most appealing feature to be used in phased array solutions.