Isolation improvement and user-effect modeling for antenna arrays in 5G and beyond

Mikko Heino

Antenni-isolaation parantaminen ja käyttäjän vaikutus tulevaisuuden matkapuhelinjärjestelmissä

Mikko Heino

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Matkapuhelinjärjestelmien kehitys on ollut nopeaa viime vuosikymmeninä. Uusia teknologioita tarvitaan vastaamaan yhä kasvaviin tiedonsiirron kapasiteettivaatimuksiin käyttäjien lukumäärän kasvaessa ruuhkautuvilla taajuuskaistoilla. Tämä väitöskirja käsittelee useita sähkömagneettisia rakenteita ja mallinnusmenetelmiä, jotka mahdollistavat tulevaisuuden viestintäjärjestelmät. Samantaajuinen ja samanaikainen lähetys ja vastaanotto (in-band full-duplex, IBFD) mahdollistaa sähkömagneettisen spektrin käytön hyötysuhteen kaksinkertaistamisen parhaassa tapauksessa verrattuna tähänastisiin taajuus- tai aikajakoisuuden periaatteella toimiviin järjestelmiin. IBFD:n ongelma on lähettimestä vastaanottimeen kytkeytyvä vahva itse-interferenssi. Väitöskirjan ensimmäisessä osassa esitetään aaltoloukku-rakenteita lähetys- ja vastaanottoantennin välisen isolaation parantamiseksi. Aaltoloukut ovat resonoivia rakenteita, joista siroava kenttä kumoaa alkuperäisen lähetysantennin kentän vastaanottoantennin ympäristössä mahdollistaen näin korkean isolaation antennien välillä. Aaltoloukkuja sovelletaan IBFD-moniantenni (MIMO) radiotoistimen antennien eristämiseen ja aaltoloukkujen suunnitteluun soveltuva uusi teoria esitetään karakteristisen mooditeorian avulla. Aaltoloukkujen toiminta varmennetaan mittauksien avulla toistimen oikeissa toimintaympäristöissä ulko- ja sisätiloissa. Samalla ympäristön monikanavaetenemisen vaikutus saavutettavissa olevaan antenni-isolaatioon selvitetään. Lisäksi ympärisäteileville dipoli-antenneille esitellään isolaatiota huomattavasti parantava rakenne, joka mahdollistaa kaksisuuntaisen IBFD:n käyttäjälaitteille. Millimetriaalto-alueen tietoliikenne on välttämätöntä tulevaisuuden matkapuhelinjärjestelmille johtuen saatavilla olevista laajoista taajuuskaistoista, jotka mahdollistavat erittäin korkeat tiedonsiirtonopeudet. Väitöskirjan toinen osa käsittelee ihmisen kehon vaikutusta käyttäjälaiteantenneihin, jotka toimivat 28 GHz:n ja 60 GHz:n taajuuksilla. Käyttäjän sormien varjostavaa vaikutusta tutkitaan kehittäen uusia menetelmiä, joilla signaalin vaimentumista voidaan vähentää keilankäännön sekä ohuen heijastimen avulla yli 20 dB. Lisäksi koko ihmiskehon vaikutusta käyttäjälaitteisiin tutkitaan millimetriaalto-alueella uuden simulointimallin avulla, joka vähentää sähkömagneettisen laskennan monimutkaisuutta mahdollistaen koko ihmisen ottamisen huomioon tarkasti simulaatioissa jopa 60 GHz:n taajuudella. Tulevaisuuden millimetriaalto-alueella toimivan matkapuhelinjärjestelmän tukiasemien tiheys täytyy olla suuri esteiden ja rakennusten aiheuttaman suuren vaimennuksen vuoksi. Väitöskirjan kolmas osa käsittelee piirilevylle valmistettavaa kustannustehokasta tukiasemakäyttöön soveltuvaa keilankääntöön perustuvaa antenniryhmää 28 GHz:n taajuudella. Suunniteltu korkean suuntaavuuden antenniryhmä mahdollistaa korkean tehotiheyden säteilyn haluttuun suuntaan vaikka korkealla toimintataajuudella piirilevytekniikasta ja kytkinverkosta aiheutuu häviöitä.

Julkaisun otsikon käännös	Antenni-isolaation parantaminen ja käyttäjän vaikutus tulevaisuuden matkapuhelinjärjestelmissä
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Haneda, Katsuyuki, Vastuuprofessori Icheln, Clemens, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-0010-5
Sähköinen ISBN	978-952-64-0011-2
Tila	Julkaistu - 2020
OKM-julkaisutyyppi	G5 Tohtorinväitöskirja (artikkeli)

Tutkimusalat

antenni-isolaatio
full-duplex
millimetriaallot
ihmisen vaikutus

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-64-0011-2

Aalto Electronics-ICT
Jussi Ryynänen (Manager)
Dept Electronics and Nanoeng.
Laitteistot/tilat: Facility

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@phdthesis{c8579a78abcc4b0c9d0d5860c4ae9da2,

title = "Isolation improvement and user-effect modeling for antenna arrays in 5G and beyond",

abstract = "The evolution of mobile phone systems has been fast in the past decades with 5G systems closely being deployed. This development of mobile networks requires new techniques to solve the ever-increasing demand for the number of users, even higher data rates, and the problem of spectrum scarcity. This dissertation describes several novel electromagnetic designs and modelling methods that enable 5G and beyond communication systems. In-band full-duplex (IBFD) communication utilizes the same frequency band for receiving and transmitting simultaneously. Thus, the spectral efficiency is doubled in the best case compared to current half-duplex systems. However, the major problem of IBFD is the strong self-interference (SI) between the transmitter and the receiver on the same device. To make IBFD communication feasible, in the first part of this thesis, electromagnetic wavetraps are proposed as a method to improve isolation between the receiving and transmitting antennas of a device. Wavetraps are resonant structures usually placed between antennas to decouple them. They suppress surface currents and scatter the transmitted electromagnetic fields suitably to cancel out the naturally coupled fields at the location of the receiving antenna, thus increasing the antenna isolation. Planar wavetraps are designed for a multiple-input-multiple-output (MIMO) IBFD relay where planar antennas are used. The methodology for designing and optimising wavetraps is established utilizing the theory of characteristic modes. The clear positive impact of the wavetraps on antenna isolation is experimentally verified both in the anechoic chamber and in realistic multipath environments. The effects of multipath environment on the obtainable isolation are characterized. The thesis furthermore introduces an antenna decoupling structure for bi-directional IBFD communications, where the isolation between omnidirectional collinear dipoles is significantly enhanced. Communication at millimetre-waves (mm-waves) is essential in future mobile communications due to wide available bandwidth that enables very high data rates. The second part of the thesis considers the effect of a human body to mm-wave handset antennas operating at 28 GHz and 60 GHz. The effect of the proximity of fingers to handset antennas is studied giving novel approaches how to mitigate the effect by utilizing beamsteering and by a thin reflector decreasing the shadowing over 20 dB. Furthermore, characterization of shadowing and scattering due to an entire human body is made possible at 60 GHz with a novel simulation model which reduces the computational complexity while keeping the modelling accuracy. Mm-wave base stations in urban areas need to be deployed densely in future communication systems to cope with expected severe link blockage. The third part of the thesis introduces a PCB-based beamsteerable end-fire antenna array at 28 GHz for low-cost base stations. The antenna array is integrated with a switch network and high gain antenna elements, obtaining high measured realized gain even with the high losses of PCB technology at 28 GHz.",

keywords = "antenna isolation, in-band full-duplex, millimeter-wave, human shadowing, antenni-isolaatio, full-duplex, millimetriaallot, ihmisen vaikutus, antenna isolation, in-band full-duplex, millimeter-wave, human shadowing",

author = "Mikko Heino",

year = "2020",

language = "English",

isbn = "978-952-64-0010-5",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "127",

school = "Aalto University",

}

TY - THES

T1 - Isolation improvement and user-effect modeling for antenna arrays in 5G and beyond

AU - Heino, Mikko

PY - 2020

Y1 - 2020

N2 - The evolution of mobile phone systems has been fast in the past decades with 5G systems closely being deployed. This development of mobile networks requires new techniques to solve the ever-increasing demand for the number of users, even higher data rates, and the problem of spectrum scarcity. This dissertation describes several novel electromagnetic designs and modelling methods that enable 5G and beyond communication systems. In-band full-duplex (IBFD) communication utilizes the same frequency band for receiving and transmitting simultaneously. Thus, the spectral efficiency is doubled in the best case compared to current half-duplex systems. However, the major problem of IBFD is the strong self-interference (SI) between the transmitter and the receiver on the same device. To make IBFD communication feasible, in the first part of this thesis, electromagnetic wavetraps are proposed as a method to improve isolation between the receiving and transmitting antennas of a device. Wavetraps are resonant structures usually placed between antennas to decouple them. They suppress surface currents and scatter the transmitted electromagnetic fields suitably to cancel out the naturally coupled fields at the location of the receiving antenna, thus increasing the antenna isolation. Planar wavetraps are designed for a multiple-input-multiple-output (MIMO) IBFD relay where planar antennas are used. The methodology for designing and optimising wavetraps is established utilizing the theory of characteristic modes. The clear positive impact of the wavetraps on antenna isolation is experimentally verified both in the anechoic chamber and in realistic multipath environments. The effects of multipath environment on the obtainable isolation are characterized. The thesis furthermore introduces an antenna decoupling structure for bi-directional IBFD communications, where the isolation between omnidirectional collinear dipoles is significantly enhanced. Communication at millimetre-waves (mm-waves) is essential in future mobile communications due to wide available bandwidth that enables very high data rates. The second part of the thesis considers the effect of a human body to mm-wave handset antennas operating at 28 GHz and 60 GHz. The effect of the proximity of fingers to handset antennas is studied giving novel approaches how to mitigate the effect by utilizing beamsteering and by a thin reflector decreasing the shadowing over 20 dB. Furthermore, characterization of shadowing and scattering due to an entire human body is made possible at 60 GHz with a novel simulation model which reduces the computational complexity while keeping the modelling accuracy. Mm-wave base stations in urban areas need to be deployed densely in future communication systems to cope with expected severe link blockage. The third part of the thesis introduces a PCB-based beamsteerable end-fire antenna array at 28 GHz for low-cost base stations. The antenna array is integrated with a switch network and high gain antenna elements, obtaining high measured realized gain even with the high losses of PCB technology at 28 GHz.

AB - The evolution of mobile phone systems has been fast in the past decades with 5G systems closely being deployed. This development of mobile networks requires new techniques to solve the ever-increasing demand for the number of users, even higher data rates, and the problem of spectrum scarcity. This dissertation describes several novel electromagnetic designs and modelling methods that enable 5G and beyond communication systems. In-band full-duplex (IBFD) communication utilizes the same frequency band for receiving and transmitting simultaneously. Thus, the spectral efficiency is doubled in the best case compared to current half-duplex systems. However, the major problem of IBFD is the strong self-interference (SI) between the transmitter and the receiver on the same device. To make IBFD communication feasible, in the first part of this thesis, electromagnetic wavetraps are proposed as a method to improve isolation between the receiving and transmitting antennas of a device. Wavetraps are resonant structures usually placed between antennas to decouple them. They suppress surface currents and scatter the transmitted electromagnetic fields suitably to cancel out the naturally coupled fields at the location of the receiving antenna, thus increasing the antenna isolation. Planar wavetraps are designed for a multiple-input-multiple-output (MIMO) IBFD relay where planar antennas are used. The methodology for designing and optimising wavetraps is established utilizing the theory of characteristic modes. The clear positive impact of the wavetraps on antenna isolation is experimentally verified both in the anechoic chamber and in realistic multipath environments. The effects of multipath environment on the obtainable isolation are characterized. The thesis furthermore introduces an antenna decoupling structure for bi-directional IBFD communications, where the isolation between omnidirectional collinear dipoles is significantly enhanced. Communication at millimetre-waves (mm-waves) is essential in future mobile communications due to wide available bandwidth that enables very high data rates. The second part of the thesis considers the effect of a human body to mm-wave handset antennas operating at 28 GHz and 60 GHz. The effect of the proximity of fingers to handset antennas is studied giving novel approaches how to mitigate the effect by utilizing beamsteering and by a thin reflector decreasing the shadowing over 20 dB. Furthermore, characterization of shadowing and scattering due to an entire human body is made possible at 60 GHz with a novel simulation model which reduces the computational complexity while keeping the modelling accuracy. Mm-wave base stations in urban areas need to be deployed densely in future communication systems to cope with expected severe link blockage. The third part of the thesis introduces a PCB-based beamsteerable end-fire antenna array at 28 GHz for low-cost base stations. The antenna array is integrated with a switch network and high gain antenna elements, obtaining high measured realized gain even with the high losses of PCB technology at 28 GHz.

KW - antenna isolation

KW - in-band full-duplex

KW - millimeter-wave

KW - human shadowing

KW - antenni-isolaatio

KW - full-duplex

KW - millimetriaallot

KW - ihmisen vaikutus

KW - antenna isolation

KW - in-band full-duplex

KW - millimeter-wave

KW - human shadowing

M3 - Doctoral Thesis

SN - 978-952-64-0010-5

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Antenni-isolaation parantaminen ja käyttäjän vaikutus tulevaisuuden matkapuhelinjärjestelmissä

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

Sormenjälki

Laitteet

Aalto Electronics-ICT

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