Multiband and Silicon Integrated Antennas for Wireless Sensor Networks

174 Pages·2011·9.84 MB·English

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Ph.D. Dissertation
Joan Gemio Valero
J Supervisor:JosepParrónGranados
. DepartmentofTelecommunicationsandSystemsEngineering
G
July,2011
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Multiband and Silicon
Integrated Antennas
for Wireless Sensor
Networks

by

Joan Gemio Valero

Ph.D. Dissertation

Supervisor: Josep Parrón Granados

Antenna and Microwave Systems Group
Department of Telecommunications and Systems
Engineering

Barcelona, July 2011

Abstract
Wireless technologies have triggered an important revolution in the world of
telecommunication networks and services. New systems, such as the latest generation
mobile phones or wireless LANs, have appeared being enthusiastically accepted by people.
In particular, applications related to remote sensor networks are growing rapidly (for
temperature monitoring, the detection of free parking spaces, etc.).
This thesis is focused on antenna design for distributed wireless sensor networks. The
remote sensors we are considering are connected to a central unit using a wireless link in
the 5.8 GHz ISM band and the central unit transmits the collected information to the
Internet via a WLAN connection.
In the central unit multiband antennas are necessary to cover several frequency bands
with a single radiating element. Two solutions to obtain this multiband performance
are proposed: fractal-based ground planes and resonator loaded monopoles. Several novel
antennas that easily meet the system requirements are manufactured and measured.
For remote sensors small dimensions and low costs are desired. The use of silicon
integratedantennasfabricatedwithstandardCMOStechnologyisagoodchoicetoachieve
these requirements. First, the main problems of antenna integration are discussed and,
then a possible solution to improve the antenna efficiency is presented together with a
study of the effects of other elements integrated in the same chip with the antenna. The
measurements of the manufactured prototypes demonstrate that antenna integration at
5.8 GHz is feasible, and that system ranges of some meters can be obtained even when
the antenna is fabricated together with other elements integrated in the same chip.
Thepossibilityofhavingsomeofthesensorsimplantedinsidethebodywillbeareality
inthenearfuture,forthisreasontheparticularcaseofimplantedantennasisalsoanalyzed.
The last part of this thesis is devoted to study the body effects on antenna performance
and evaluate the additional propagation losses introduced by the body tissues.

Agra¨ıments
En aquesta vida tot t´e un inici i un final. Ara ha arribat un dels moments m´es esperats
d’aquesta tesis, el moment d’escriure els agra¨ıments, fet que indica que aquest treball ha
arribatalasevaculminaci´o.Am´es´esl’ocasi´operfecteperdonarlesgr`aciesatotesaquelles
persones que m’han acompanyat durant aquests 4 anys.
Gr`acies Josep (director d’aquesta tesis) per donar-me l’oportunitat de realitzar aquest
treball i per poder gaudir de la teva ajuda sempre que l’he necessitat. Gr`acies tamb´e als
altres membres del grup AMS (Pedro, Oscar, Gary), per totes les aportacions que heu
fet durant aquest per´ıode. Ram´on, tot i que ja no est`as en el grup, no m’oblido pas de
tu. Jordi Soler, et vull agrair tots els comentaris que has anat fent per millorar el treball
realitzat. Felix i Jordi, gr`acies per totes les antenes fabricades. Gr`acies a tots els professors
de la ETSE, ja que sense el que ells em van ensenyar no hauria pogut fer aquesta tesis.
Tamb´e vull agrair l’ajuda rebuda per part de membres d’altres institucions: a Jose
Maria Gonz´alez Arbesu´ (UPC) per ajudar-me a fer les mesures dels diagrames de radiaci´o
i a Jordi Sacrist´an (CNM) i Toni Baldi (CNM), per fer possible que pogu´es fabricar les
antenes integrades en silici.
Gr`acies a tots els company del despatx (Mo´nica, Jordi, Eden, Rafa, Mercedes, Verdu´)
i als que no esteu en el despatx (Jose, Toni) per haver fet m´es entretinguts els dies que ens
hem passat aqu´ı tancats treballant. Algun@s de vosaltres heu estat molt m´es que simples
company@s de feina, i espero que aquesta amistat perduri en el futur.
A tota la gent que fora de la universitat m’ha donat suport i m’ha ajudat a gaudir
d’aquest per´ıode, tamb´e els vull dir gr`acies. Gr`acies Monica, Oscar, Jordi, Laia, i gr`acies
tamb´e a tots els del ”Patinet” (Anna, August, Canari, David, Jaume, Jordi, ......) per
haver compartit amb mi molts caps de setmana, ja sigui sobre dues o quatre rodes.
Pare, mare i avis, a vosaltres us deixo pel final. Vosaltres em vareu motivar a iniciar
aquesta tesis i sempre heu estat presents en aquest llarg cam´ı. Heu suportat el meu mal
humor quan les coses no anaven com jo volia i sempre heu estat all`a, animant-me a tirar
endavant i a arribar al final d’aquest cam´ı que vaig iniciar ja fa un bon temps. Moltes
gra`cies per tot, i recordeu que aquesta tesis va dedicada a vosaltres !!!!
Joan Gemio Valero, Juliol 2011

This work has been supported by the Spanish Ministry of Science and Innovation
through grants TEC2006-13248-C04-01 and TEC2009-13897-C03-02, and by the
Spanish Ministry of Education through the FPU program.
Silicon integrated antennas were manufactured in the integrated clean room for micro
and nano manufacturing of Instituto de Microelectr´onica de Barcelona - Centro Nacional
de Microelectr´onica (IMB-CNM) supported by the Spanish Ministry of Science and
Innovation through the GICSERV program ref. 2009-NGG 151 and ref.
2010-NGG 183.
Radiation pattern measurements were carried out at the anechoic chamber of the
Antenna Lab group of the Universitat Politecnica de Catalunya.

Contents
1 Introduction 1
1.1 Wireless communication systems: New trends and use of the ISM bands . . 1
1.1.1 New trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.2 Use of the ISM bands . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Motivation and focus of this thesis . . . . . . . . . . . . . . . . . . . . . . . 4
1.2.1 Thesis motivation and system description . . . . . . . . . . . . . . . 4
1.2.2 Focus of the thesis and objectives . . . . . . . . . . . . . . . . . . . . 5
1.3 Thesis organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 List of Author’s Contributions . . . . . . . . . . . . . . . . . . . . . . . . . 8
2 Multiband antennas for the central unit 11
2.1 Introduction to multiband antennas . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Multiband antennas inspired by fractal geometries . . . . . . . . . . . . . . 15
2.2.1 Introduction to the use of fractal shapes in antenna design . . . . . 16
2.2.2 The Sierpinski monopole . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2.3 Use of the Sierpinski gasket in the ground plane . . . . . . . . . . . 26
2.3 Resonator loaded multiband monopole antennas . . . . . . . . . . . . . . . 37
2.3.1 Introduction to resonator loaded antennas . . . . . . . . . . . . . . . 37
2.3.2 Dual band resonator loaded monopole antenna . . . . . . . . . . . . 40
2.3.3 Triple band SRR loaded monopole antenna . . . . . . . . . . . . . . 46
2.3.4 Triple band resonator loaded monopole antenna based on the use of
an asymmetric structure . . . . . . . . . . . . . . . . . . . . . . . . . 52
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