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Micro- and Millimeter Wave CMOS Beamforming Receivers

Axholt, Andreas LU (2011)
Abstract (Swedish)
Popular Abstract in Swedish

Det tillgängliga frekvensutrymmet i trådlösa kommunikationssystem, så som trådlösa datornätverk, är mycket begränsat. Detta tillsammans med den ökande trafikmängden skapar problem. Nya möjligheter finns dock i och med att det finns stora mängder bandbredd som är licensfri för användning. Ökad bandbredd möjliggör också ökad datahastighet. Det tillgängliga frekvensbandet ligger dock vid betydligt högre frekvens, 60 GHz, än vad som använts i tidigare system för privat bruk. Detta medför nya utmaningar, dels ur systemperspektiv men även ur kretsperspektiv. Hand i hand med utmaningar medföljer även helt nya möjligheter, så som möjligheten att överföra mycket stora mängder data på kort tid mellan... (More)
Popular Abstract in Swedish

Det tillgängliga frekvensutrymmet i trådlösa kommunikationssystem, så som trådlösa datornätverk, är mycket begränsat. Detta tillsammans med den ökande trafikmängden skapar problem. Nya möjligheter finns dock i och med att det finns stora mängder bandbredd som är licensfri för användning. Ökad bandbredd möjliggör också ökad datahastighet. Det tillgängliga frekvensbandet ligger dock vid betydligt högre frekvens, 60 GHz, än vad som använts i tidigare system för privat bruk. Detta medför nya utmaningar, dels ur systemperspektiv men även ur kretsperspektiv. Hand i hand med utmaningar medföljer även helt nya möjligheter, så som möjligheten att överföra mycket stora mängder data på kort tid mellan datorn och dess kringutrustning, överföring av HD-video från/till smartphone, eliminera kablar mellan videokälla och projektor, etc.

Vågutbredning vid 60 GHz skiljer sig ifrån dagens trådlösa nätverk system som arbetar kring 2.4 och 5.8 GHz. Det mest påtagliga är utbredningsdämpningen, vilken begränsar möjligt avstånd mellan sändare och mottagare. Utbredningsegenskaper som påverkas är; hur radiovågen viker sig runt föremål, styrka hos reflexioner, samt dess propageringsegenskaper genom olika material.

Teknologin som används för integrerade kretsar i massmarknadssegmentet domineras klart av CMOS, då denna teknologi erbjuder låga produktionskostnader vid höga volymer. Att implementera höghastighetskommunikation vid 60 GHz i CMOS ansågs för inte länge sedan omöjligt. Dock har utvecklingen av teknologin fullständigt stormat fram vilket har lett till otroliga prestandaökningar. En stor del av prestanda förbättringen beror på att transistorn görs mindre. Processortillverkare planerar att tillverka nästa generations processorer i 22nm CMOS. Detta är positiva nyheter för konstruktörer av högfrekvenskretsar, eftersom ännu snabbare transistorer kan förväntas.

Det uppstår dock även en del svårigheter med mindre transistorer. Då transistorns storlek krymps ökar det elektriska fältet i komponenten, om samma matningsspänning används. Detta resulterar i att komponenten snart går sönder. Med sänkt matningsspänning ökar livslängden, men samtidigt reduceras möjlig uteffekt från sändaren. Mindre uteffekt tillsammans med ökade transmissionsförluster vid 60 GHz gör situationen problematisk – Hur skall mottagaren kunna detektera signalen?

Att implementera flera mottagare som arbetar tillsammans ökar mängden signal som tas emot. Vid 60 GHz har antenndimensionen reducerats till storleksordningen 1mm, då storleken är omvänt proportionell mot frekvensen. Ökad frekvens medför alltså en mindre antenn, vilket gör det möjligt att implementera flera 60 GHz antenner utan att lösningen blir

otymplig. Det krävs dock att mottagaren kan kombinera dessa signaler på ett gynnsamt vis. Detta görs genom att förskjuta de inkommande signalerna i tiden så att signalerna adderas ”på varandra”. Den önskade tidsförskjutningen mellan antennerna beror av signalens inkommande vinkel. Alltså, beroende på var i rummet signalen sänds, relativt mottagaren, kommer signalerna till vart antennelement att behöva fördröjas olika, vilket kallas beamforming. Intressant att notera är att signaler från andra riktningar kommer att adderas destruktivt, vilket dämpar oönskade signaler. Då tidsfördröjande kretsar är praktiskt svåra att implementera används sambandet att en tidsfördröjning kan liknas med en fasförskjutning, vilket lättare låter sig göras.

Avhandlingen behandlar kretsimplementationer av viktiga delar av beamformingmottagare för 60 GHz i CMOS. I introduktionen ges en sammanfattning av problematiken kring 60 GHz kretsar i CMOS teknologi, olika beamformingtopologier, följt av de inkluderade vetenskapliga artiklarna. (Less)
Abstract
The available bandwidth in wireless communication systems, such as the 802.11 family, is very limited. Together with the ever increasing data traffic, this causes problems. New possibilities are, however, available thanks to wide license-free bandwidth allocated at higher frequencies. Increased available bandwidth enables higher data rates in future radio systems that will be capable of Giga-bit/s communication applications.

This creates new possibilities like transferring very large amounts of data in a short time between computers and their peripheral devices, wireless HD-video to and from smart phones, eliminating cables between video-source and video-projector, etc. The available bandwidth is, however, located at much higher... (More)
The available bandwidth in wireless communication systems, such as the 802.11 family, is very limited. Together with the ever increasing data traffic, this causes problems. New possibilities are, however, available thanks to wide license-free bandwidth allocated at higher frequencies. Increased available bandwidth enables higher data rates in future radio systems that will be capable of Giga-bit/s communication applications.

This creates new possibilities like transferring very large amounts of data in a short time between computers and their peripheral devices, wireless HD-video to and from smart phones, eliminating cables between video-source and video-projector, etc. The available bandwidth is, however, located at much higher frequencies than in current WiFi systems for private usage, that is, 2.4 and 5.8 GHz. This brings new challenges

from both a system as well as a circuit perspective. Wave propagation at 60 GHz differs from 2.4 GHz and 5.8 GHz. The most substantial differences are the propagation loss and the small aperture of the millimeter wave antennas, which limit the possible communication distance between receiver

and transmitter. Adopting beamforming transmitters focuses the transmitted energy into the desired direction, increasing the energy available at the receiver. Correspondingly, adopting beamforming receivers also increases the received signal energy by increasing the antenna gain. Beamforming is, therefore, a key technique in increasing communication distance. This thesis investigates CMOS beamforming receiver circuits and architectures for microwave and millimeter wave radio communication. Traditionally, III-V semiconductor technologies have been used for millimeter wave applications. Today, however, as the gate length of silicon CMOS devices has been continuously reduced thanks to advancements in IC fabrication, their maximum frequency of operation is also sufficient for millimeter waves. Several circuits have been designed and measured to validate new ideas. Among these circuits, five are included in the thesis. A chip with

two fully-integrated phase-locked loops with digital phase control for beamforming receivers is presented in paper I, and an injection locked voltage controlled oscillator with phase control is presented paper II. A two channel 24 GHz receiver with beamforming implemented in the analog baseband is proposed in paper III, and a high-speed low-power inductor-less 24 GHz CML frequency divider is presented in paper IV, including an on-chip VCO for test purposes. Finally, in paper V a 60 GHz

receiver with a digitally controllable phase using a phase-locked loop, based on the results of paper I, is presented. The circuit achieves a state-of-the-art phase control accuracy with a measured phase step error of less than 1 degree. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Nauta, Bram, University of Twente, Enschede, Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
keywords
beamforming, CMOS, front-end, microwave, millimeter wave, phase-locked loop, phased-array
pages
124 pages
defense location
Lecture Hall E:1406, E-building at Faculty of Engineering
defense date
2011-09-07 10:15
ISSN
1654-790X
ISBN
978-91-7473-146-0
project
EIT_HSWC:RFNano RF tranceivers and nano devices
language
English
LU publication?
yes
id
ad967e2b-b17c-4e7a-9105-4d9e63b698d6 (old id 1978460)
date added to LUP
2011-06-16 08:56:24
date last changed
2016-09-19 08:45:01
@phdthesis{ad967e2b-b17c-4e7a-9105-4d9e63b698d6,
  abstract     = {The available bandwidth in wireless communication systems, such as the 802.11 family, is very limited. Together with the ever increasing data traffic, this causes problems. New possibilities are, however, available thanks to wide license-free bandwidth allocated at higher frequencies. Increased available bandwidth enables higher data rates in future radio systems that will be capable of Giga-bit/s communication applications.<br/><br>
This creates new possibilities like transferring very large amounts of data in a short time between computers and their peripheral devices, wireless HD-video to and from smart phones, eliminating cables between video-source and video-projector, etc. The available bandwidth is, however, located at much higher frequencies than in current WiFi systems for private usage, that is, 2.4 and 5.8 GHz. This brings new challenges<br/><br>
from both a system as well as a circuit perspective. Wave propagation at 60 GHz differs from 2.4 GHz and 5.8 GHz. The most substantial differences are the propagation loss and the small aperture of the millimeter wave antennas, which limit the possible communication distance between receiver<br/><br>
and transmitter. Adopting beamforming transmitters focuses the transmitted energy into the desired direction, increasing the energy available at the receiver. Correspondingly, adopting beamforming receivers also increases the received signal energy by increasing the antenna gain. Beamforming is, therefore, a key technique in increasing communication distance. This thesis investigates CMOS beamforming receiver circuits and architectures for microwave and millimeter wave radio communication. Traditionally, III-V semiconductor technologies have been used for millimeter wave applications. Today, however, as the gate length of silicon CMOS devices has been continuously reduced thanks to advancements in IC fabrication, their maximum frequency of operation is also sufficient for millimeter waves. Several circuits have been designed and measured to validate new ideas. Among these circuits, five are included in the thesis. A chip with<br/><br>
two fully-integrated phase-locked loops with digital phase control for beamforming receivers is presented in paper I, and an injection locked voltage controlled oscillator with phase control is presented paper II. A two channel 24 GHz receiver with beamforming implemented in the analog baseband is proposed in paper III, and a high-speed low-power inductor-less 24 GHz CML frequency divider is presented in paper IV, including an on-chip VCO for test purposes. Finally, in paper V a 60 GHz<br/><br>
receiver with a digitally controllable phase using a phase-locked loop, based on the results of paper I, is presented. The circuit achieves a state-of-the-art phase control accuracy with a measured phase step error of less than 1 degree.},
  author       = {Axholt, Andreas},
  isbn         = {978-91-7473-146-0},
  issn         = {1654-790X},
  keyword      = {beamforming,CMOS,front-end,microwave,millimeter wave,phase-locked loop,phased-array},
  language     = {eng},
  pages        = {124},
  school       = {Lund University},
  title        = {Micro- and Millimeter Wave CMOS Beamforming Receivers},
  year         = {2011},
}