EMC, RF, and Antenna Systems in Miniature Electronic Devices

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EMC, RF, and Antenna Systems in Miniature Electronic Devices
Ruaro, Andrea
Publication date:
2016
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Citation (APA):
Ruaro, A. (2016). EMC, RF, and Antenna Systems in Miniature Electronic Devices. Technical University of
Denmark, Department of Electrical Engineering.

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EMC, RF, and Antenna Systems in
Miniature Electronic Devices
Ph.D. Thesis
Andrea Ruaro
January 2016
The present work was carried out at GN ReSound A/S (place of employment)
and at DTU Electrical Engineering in partial fulfilment of the requirements for
the Ph.D. degree from the Technical University of Denmark.
Supervisors:
Kaj Bjarne Jakobsen, Ph.D.
Electromagnetic Systems, DTU Elektro, Technical University of Denmark
Jesper Thaysen, Ph.D.
GN ReSound A/S

The well in which Truth is said to reside is really a bottomless pit.
– Oliver Heaviside, in Electromagnetic Theory, 1893.
i

Abstract
Advanced techniques for the control of electromagnetic interference (EMI)
and for the optimization of the electromagnetic compatibility (EMC) perfor-
mancehasbeendevelopedundertheconstraintstypicalofminiatureelectronic
devices (MED). The electromagnetic coexistence of multiple systems and their
mutual interaction have been the underlying theme of the work. The research
results concern different aspects related to the integration of radio-frequency
(RF) electronics in MEDs and hearing instruments (HI).
To control internal EMI, a novel near-field parasitic resonator (NFPR) has
beenresearched. Thestructureallowsforeffectivesuppressionofradiationfrom
the MED, while taking into consideration the integration and miniaturization
aspects. To increase the sensitivity of the system, a compact LNA suitable for
on-body applications has been developed. The LNA allows for an increase in
the overall sensitivity of a system comprised of two HIs communicating among
them.
To optimize the on-body and off-body communication links of HIs, a novel
wearableantennawasdesigned. Thedesignoriginatesfromconsiderationsabout
the EM environment where the antenna operates. An EMC-robust alternative
to the on-body link was investigated through the use of body-coupled commu-
nications (BCC) and integrated with the antenna in a unique system.
Overall, the novel researched solutions effectively addressed a set of intra-
andinter-systemEMIandEMCissues,asdictatedbythecomplexityofemerg-
ing modern miniature electronics.
iii

Resum´e
Avancerede teknikker til reduktion af elektromagnetisk interferens (EMI)
og optimering af elektromagnetisk kompatibilitet (EMC) er udviklet under de
begrænsninger,somertypiskforminiaturiseretelektroniskudstyr(MED).Den
elektromagnetiskesameksistensaffleresystemerogderesindbyrdessamspil,har
væretdetunderliggendeemnefordettearbejde.Forskningsresultaternevedrører
forskellige aspekter relateret til integrationen af radiofrekvenselektronik (RF-
elektronik) i MED og høreapparater (HI).
For at kunne kontrollere den interne EMI, er en nærfeltsparasitresonator
(NFPR)blevetudforsket.Strukturentilladereffektivtundertrykkelseafstr˚alingen
fra MED, idet der tages hensyn til integrations- og miniaturiseringsaspekter.
Foratøgesystemfølsomheden,erderudvikletenkompaktLNA,derervelegnet
til p˚a-kroppen-applikationer. LNAen giver mulighed for at forøge den samlede
følsomhed af systemet, der best˚ar af to høreapparater, der kommunikerer med
hinanden.
For at optimere p˚a-krop og ud-af-krop kommunikationsforbindelsen, er der
designet en ny bærbar antenne. Designet hidrører fra overvejelser om det elek-
tromagnetisk miljø, hvori antennen skal fungere. Et EMC-stærk alternativ til
etlinkp˚akroppen,erblevetundersøgtvedbrugafkropskobletkommunikation
(BCC), der er integreret med antennen til et unikt system.
Samletsetadressererdenyeforskningsløsningereffektivtetsætafintra-og
intersystemEMI-ogEMC-problemer,somdikteresafkompleksitetenafmoder-
ne miniaturiseret elektronik.
v

Sommario
Tecnicheavanzateperilcontrollodelleinterferenzeelettromagnetiche(EMI)
e per l’ottimizzazione della compatibilita` elettromagnetica (EMC) sono state
studiate sotto i vincoli caratteristici dei dispositivi elettronici miniaturizzati
(MED). La coesistenza elettromagnetica di diversi sistemi e la loro interazio-
ne reciproca sono stati i temi sottostanti del lavoro. I risultati della ricerca
riguardanodiversiaspettidell’integrazionedielettronicaaradiofrequenza(RF)
in dispositivi miniaturizzati e apparecchi acustici (HI).
La ricerca esamina una nuova struttura, cio`e un risuonatore parassita (NF-
PR)postoinprossimit`adiunasorgenteelettromagnetica,percontrollarel’inter-
ferenzainterna. Lastrutturapermettelasoppressioneeffettivadellaradiazione
generata in un dispositivo, tenendo conto degli aspetti di integrazione e mi-
niaturizzazione dell’elettronica. Un compatto amplificatore a bassa figura di
rumore(LNA)adattoperapplicazioniindossabili`esviluppatopermigliorarela
sensibilita` del circuito radio. L’amplificatore permette un miglioramento della
sensibilita` complessiva di un sistema composto da due apparecchi acustici che
comunicano tra loro.
Una nuova antenna, adatta ad essere indossata, `e stata progettata per ot-
timizzare i collegamenti radio degli apparecchi acustici. Il concetto`e sviluppa-
to a partire da considerazioni sull’ambiente elettromagnetico in cui l’antenna
si trova ad operare. Un collegamento radio alternativo, robusto da una pro-
spettiva di compatibilita` elettromagnetica, `e stato studiato attraverso l’uso di
comunicazioni intra-corpo e integrato con l’antenna in un unico sistema.
Nel complesso, le nuovi soluzioni studiate affrontano con efficacia una serie
di problemi di EMI e EMC, sia interni all’elettronica che riguardanti l’intera-
zioneconaltridispositivi,chestannoemergendoacausadellacomplessita`della
moderna elettronica in miniatura.
vii