microwave and millimetre wave design for wireless communications pdf

15 Digital Signal Processing for Transceivers 46415.3 DSP in Modern Wireless Communications Systems 467 16.9 System-in-Package and System-on-Substrate Technology 509 16.10 Transitions an

MICROWAVE AND

MILLIMETRE-WAVE

DESIGN FOR WIRELESS COMMUNICATIONS

First Edition published in 2016

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A catalogue record for this book is available from the British Library.

Set in 10/12pt Times by Aptara Inc., New Delhi, India

1 2016

2.2.6 Antenna 37

2.5.7 Orthogonal Frequency Division Multiplexing (OFDM) Modulation 58

2.5.8 Comparison of Eb/N0versus BER for Various Modulation Schemes 59

2.6 Noise Analysis and Link Budget Calculation 61

4.3 Butterworth, Chebyshev and Elliptic Low-Pass Prototypes 107

5.4 Standing Waves on a Lossless Transmission Line

5.5 The Smith Chart 142

8.7 RFICs and MMICs 271

9.5 The Cyclic Nature of Distributed Circuits 295

10.3 Classical Analysis of Gain and Stability 302

12.7 Mixer Linearisation and Adaptive Signal Cancellation 412

13.2 Novel Transceiver Architectures using RF MEMS 416

13.3 Micromachined Transmission Lines and Passive Elements 416

Contents xiii

13.5 Reconfigurable Impedance-Matching Networks 424

13.10 Reliability and Design Consideration of RF MEMS Devices 430

15 Digital Signal Processing for Transceivers 464

15.3 DSP in Modern Wireless Communications Systems 467

16.9 System-in-Package and System-on-Substrate Technology 509

16.10 Transitions and Antenna-in-Package Techniques 512

17.8 Integrated Circuit Simulation and Layout 534

18.3 Function Generator and Arbitrary Waveform Generator 542

About the Authors

Ian Robertsonreceived his BSc (Eng.) and PhD degrees from King’s College London in 1984and 1990, respectively From 1984 to 1986 he worked in the GaAs MMIC Research Group atPlessey Research, Caswell After that he returned to King’s College, initially as a ResearchAssistant working on the T-SAT project and then as a Lecturer, leading the MMIC ResearchTeam and becoming Reader in 1994 In 1998 he was appointed Professor of MicrowaveSubsystems Engineering at the University of Surrey, where he established the MicrowaveSystems Research Group and was a founder member of the Advanced Technology Institute

In June 2004 he was appointed to the Centenary Chair in Microwave and Millimetre-WaveCircuits at the University of Leeds He was Director of Learning and Teaching from 2006 to

2011 and Head of School from 2011 to 2016 He has 30 years of teaching experience in RF andmicrowave engineering and has published over 400 peer-reviewed research papers He edited

the book MMIC Design published by the IEE in 1995 and co-edited the book RFIC & MMIC

Design and Technology, published in English in 2001 and in Chinese in 2007 He was elected

Fellow of the IEEE in 2012 in recognition of his contributions to MMIC design techniquesand millimetre-wave system-in-package technology He was General Technical ProgrammeCommittee Chair for the European Microwave Week in 2011 and 2016

Nutapong Somjitreceived the Dipl.-Ing (MSc) degree from Dresden University of nology in 2005 and the PhD degree from the KTH Royal Institute of Technology in 2012.Then, he returned to Dresden to lead a research team in micro-sensors and MEMS ICs for theChair for Circuit Design and Network Theory In 2013, he was appointed Lecturer (AssistantProfessor) in the School of Electronic and Electrical Engineering, University of Leeds Hismain research focuses on RFICs, RF MEMS, tuneable antennas, and RFIC-MEMS integra-tion Dr Somjit was the recipient of the Best Paper Award (EuMIC prize) at the EuropeanMicrowave Week in 2009 He was awarded a Graduate Fellowship from the IEEE MicrowaveTheory and Techniques Society (MTT-S) in 2010 and 2011, and the IEEE Doctoral ResearchAward from the IEEE Antennas and Propagation Society in 2012 He was appointed a mem-ber of the Engineering, Physical and Space Science Research Panel of the British Council

Tech-in 2014 He serves as a reviewer for various Tech-international journals, Tech-includTech-ing IEEE

Trans-actions on Microwave Theory and Techniques Since 2013, he has been a member of the

International Editorial Board of the International Journal of Applied Science and Technology.

In 2016, he was the Chair of the Student Design Competition for the European MicrowaveWeek

Mitchai Chongcheawchamnanwas born in Bangkok, Thailand He received the BEng degree

in Telecommunication from King Mongkut’s Institute of Technology Ladkrabang, Bangkok in

1992, the MSc degree in Communication and Signal Processing from Imperial College London

in 1995 and the PhD degree in Electrical Engineering from the University of Surrey, Guildford,

UK, in 2001 He joined the Faculty of Engineering, Prince of Songkla University, Thailand,

in 2008 as an Associate Professor He has published more than 100 papers in internationaljournals and conferences in RF, microwave and millimetre-wave engineering and agriculturalapplications He has one international patent (pending), five national patents (pending) andthree international innovation awards Currently, he is a Director of Academic Outreach at thePrince of Songkla University, Hat Yai campus, Thailand

First and foremost we would like to thank all those students (undergraduate, masters and PhD)and colleagues from industry and academia that have shared their experience with us overmany years Students, in particular, often asked fundamental questions that challenged ourunderstanding of perceived wisdom in RF engineering – it is widely recognised these daysthat it is only when you teach a subject that you fully understand it, and we think that this hasbenefitted this book enormously We would, in turn, like to thank all our own teachers, fromschool through to PhD study, who taught, guided and supported us, inspiring us to developcareers in engineering, with special thanks to Charles Turner, E.M Deeley, P.R Adby, HamidAghvami and Joachim Oberhammer

We are very grateful to the people at Keysight Technologies, Plextek RFI, Phase 2 Devices,Rako Controls and Instrumentel for providing photographs to help put the text and diagramsinto proper context Some of the content has been informed by our own cutting-edge researchand we are grateful to all those funding agencies that have supported us, especially the Engi-neering and Physical Sciences Research Council (EPSRC, UK), the European Commission,Vinnova (Sweden) and the Thailand Research Fund

We are grateful for the assistance with diagrams and teaching materials provided byUmer Shah, Nemr Al Thalathiney, Hassan Al Nasser, Ali Alameer, Matthew Gillick, AyodejiSunday, Burawich Pamornnak, Sahapong Somwong, Kritsada Poungsuwan, Huda Kosumpanand Silachai Moongdee

Mitchai Chongcheawchamnan would like to thank his colleagues at the Electrical neering (EE) Department, Faculty of Engineering, Prince of Songkla University (PSU) forproviding this opportunity and supporting this book Special thanks are due to Dr KiattisakWongsopanakul, Head of the EE department and colleagues from the Faculty of Engineering,who permitted sabbatical leave to allow time to write this book

Engi-Finally, we would all like to thank our families for their love and support and for allowing

us to spend so much time on this book instead of being with them

Ian RobertsonNutapong SomjitMitchai Chongcheawchamnan

April 2016

The book describes a full range of contemporary techniques for the design of transmittersand receivers for communications systems operating in the range from 1 through to 300 GHz.Within this frequency range there are many technologies that need to be employed, withsilicon integrated circuits at the core but, compared to other electronic systems, with a muchgreater need for specialist devices and components for high performance – for example, low-loss passive components and low-noise and high-power compound semiconductor devices.Millimetre-waves (frequencies from 30 to 300 GHz) have rapidly been adopted for a wide range

of consumer applications such as wireless high-definition video for virtual and augmentedreality, 5G mobile systems, and automotive radars It has taken many years to develop low-cost technologies for suitable transmitters and receivers, so previously these frequencies havebeen employed only in expensive military and space applications This really does represent

a new era in the use of the millimetre-wave part of the electromagnetic spectrum The next 20years will see explosive growth in the use of the frequency range from 30 to 300 GHz, and thisrequires engineers to be able to understand and apply the techniques of traditional microwaveengineering, as well as the newer technologies such as silicon germanium and gallium nitridedevices and integrated circuits These are then assembled into sophisticated multichip modulesand system-in-package products with integrated antenna arrays

The book starts with an emphasis on the applications of microwave and millimetre-wavesystems, in Chapter 1, followed by a description of the wide range of modern transmitter-receiver architectures in Chapter 2 The use of quadrature modulation schemes and moderndirect-conversion transceivers, that are at the heart of nearly all wireless communication

systems, are covered Chapter 3 introduces S-parameters so that they can be used in Chapter 4

on Lumped Element Filters This introduces Bode plots, transfer functions, poles and zeros and

the s-domain, followed by design techniques for low-pass, high-pass, band-pass and bandstop

filters However, a key conclusion of this chapter is that lumped elements often suffer fromserious limitations in high-frequency design, which is why transmission lines are needed formany circuits

Chapter 5 introduces the main principles of transmission lines, including the telegrapher’sequation, signal flowgraphs, standing waves, impedance transformation along a line and the

Smith chart This is followed by Chapter 6 on transmission line components, which is focused

on the practical aspects of the main transmission line types – coaxial lines, rectangular uide, microstrip and various others, including coplanar waveguide (CPW) and substrate inte-grated waveguide (SIW) The emphasis is on those transmission line media that are used forcircuit design, looking at their propagation characteristics, technologies and materials, discon-tinuities and modelling A number of key standard components are introduced, such as theWilkinson power divider, Lange coupler, branch-line coupler and rat-race hybrid

waveg-Having covered the key transmission line media, Chapter 7 returns to the subject of filters

A succinct coverage of distributed filters is given, covering those topologies most commonlyencountered in modern microwave and millimetre-wave design The mathematical conversionfrom lumped element filters to distributed elements, followed by network transformation toproduce realisable practical filters, is described

Chapter 8 introduces the key semiconductor devices – both discrete low-noise and power transistors and those used for integrated circuits The chapter summarises the keyfeatures of silicon, silicon–germanium, GaAs, GaN and InP transistors Chapter 9 explainsthe importance of impedance matching, with particular reference to amplifier design The use

high-of the Smith chart is introduced and a number high-of common matching techniques is described.Chapter 10 builds on this by describing amplifier design techniques, starting with the classical

gain and stability analysis using S-parameter and Mason’s rule analysis The key topologies

used in GaAs MMIC and silicon RFIC design are introduced Distortion and intermodulation

in power amplifiers is explained, followed by a summary of key classes of operation (A, AB,

C, D, E, F, etc.) and a brief treatment of the main techniques employed for power-combiningand linearising power amplifiers

Chapter 11 introduces the fundamentals of oscillators, followed by coverage of the main

oscillator circuit topologies The importance of resonator Q-factor and phase noise are

explained Phase-locked loop techniques are covered, giving an introduction to integer-N andfractional-N frequency synthesis Mixers are the core component for up- and down-conversion

of signals, including use in ‘IQ’ direct conversion transceivers Chapter 12 focuses on the mostcommon mixer design techniques, including the Gilbert cell mixer technique, now adoptedeven beyond 100 GHz

Chapter 13 describes radiofrequency microelectromechanical systems (MEMS), whichare an important niche technology that can substantially change the architecture of mod-ern transceivers RF MEMS are of increasing interest as adaptive antennas, and multibandtransceivers become key to future communications systems Switches, phase shifters andreconfigurable circuits are also covered

Chapter 14 gives an overview of the basics of antennas and propagation since, in order

to understand the challenge of exploiting the millimetre-wave part of the electromagneticspectrum, it is necessary to study the propagation characteristics in the range 1 to 1000 GHz.Millimetre-waves give the very significant advantage of small, high-gain antennas, and moderncommunications systems are relying more than ever on adaptive and multiple-beam antennas inorder to combat propagation effects and increase the capacity of systems The chapter thereforeintroduces the key concepts such as multiple input/multiple output (MIMO) systems.Modern communications systems nearly always use direct conversion architectures, and

it is important that RF engineers have some understanding of the digital part of the system.Consequently, Chapter 15 provides an introduction to some of the digital signal processing(DSP) techniques used for communications transceivers The chapter also provides a tutorial

Preface xxiii

on the key principles of analogue-to-digital and digital-to-analogue converters and DSP niques This is important so that RF engineers understand how DSP is used to combat signalimpairments and realise functions such as beam forming

tech-The final three chapters describe how all the devices, components and circuits covered inthe previous chapters are assembled, simulated and measured Chapter 16 describes the maintechnologies and design techniques for microwave circuit assemblies and multichip modules,

as well as emerging 3-D system-in-package and ‘system-on-substrate’ technologies Chapter

17 covers electronic design automation (EDA), describing the most common design tools used

by designers The aim here is that the reader will fully understand the role and limitations ofdifferent simulation techniques, including linear, time-domain nonlinear, harmonic balance,modulation domain, planar electromagnetic, 3-D electromagnetic and system-level simula-tion Finally, Chapter 18 covers measurement techniques, including vector network analysercalibration methods A wide range of test equipment for measuring individual devices andcomponents through to complete transmitters and receivers is described, using Keysight Tech-nologies equipment as examples

We sincerely hope that you find this book useful Microwave and millimetre-wave design is

a fascinating subject, and is possibly unique in the way it blends electronic circuits into works

of art – such is the importance of their physical form in determining function That, combinedwith the amazing potential for wireless communications to transform every aspect of humanendeavour, makes RF engineering one of the most rewarding careers of all

Ian RobertsonNutapong SomjitMitchai Chongcheawchamnan

April 2016

Introduction

The rapid convergence of wireless communications systems and digital media has been one

of the most exciting developments in electronics during recent years Increasingly, consumerelectronics is the driving force behind technological advance, whereas in the past it was militaryand space projects Consumer electronics has become the leading edge of technology because

of the potentially huge sales volumes As the market is extremely competitive, major globalcompanies invest large sums in research and development in order to introduce new productswith more features and better performance than their rivals One of the biggest growth areas hasbeen in mobile internet connectivity through smartphones and tablets, leading to a paradigmshift towards cloud computing, shown by the dramatic growth in mobile subscriptions andinternet traffic 5G heralds a new era in which wireless connectivity reaches everything,with the Internet of Things (IoT) creating a revolution in almost every facet of modern life,including healthcare, smart cities, energy, robotics, manufacturing, retail and the creativeindustries

In the business of consumer electronics, it is well known that customers generally get(and, indeed, expect) more features for less money as technology advances The key tothis has been the continual and rapid development of silicon technology, allied with theglobalisation of the electronics manufacturing business By putting more transistors onto asingle integrated circuit (IC), clearly a given product will require less ICs and less associatedcomponents on a circuit board Gordon Moore, a cofounder of Intel, predicted in 1965 thatthe complexity of a chip could be expected to increase exponentially with time for a number

of years [1] This famous prediction has developed into Moore’s Law, which is an empiricallaw that accurately charts technological progress in the microelectronics industry, with thenumber of transistors on a chip doubling every year Figure 1.1 shows a graph charting thisevolution of Intel microprocessor technology, re-plotted on a linear scale to show the dramaticdevelopment of computer technology, and illustrates that we have only recently entered theinformation age The impressive milestone of two billion transistors on a chip was reached in

2008 [2]

Microwave and Millimetre-Wave Design for Wireless Communications, First Edition.

Ian Robertson, Nutapong Somjit and Mitchai Chongcheawchamnan.

© 2016 John Wiley & Sons, Ltd Published 2016 by John Wiley & Sons, Ltd.

Pentium

Pentium III Coppermine

Pentium IV Prescott

Core2 Duo Conroe

Quad Core i7 Bloomfield

Itanium Quad Core

Figure 1.1 Microprocessor transistor count versus year on a linear scale

1.1 A Brief Timeline of Consumer Electronics

“We only recently entered the information age” is a bold claim that requires substantiation Aworthy method of investigating the claim is to briefly study the history of consumer electron-ics and develop a timeline of how the main audio, video and communications products havedeveloped Figure 1.2 shows a simplified timeline of some of the most important developments

After various pioneering efforts to record audio, including Thomas Edison’s cylinder-basedPhonograph, in 1887 Emile Berliner patented the disc-based machine (the Gramophone) thatthat is similar to what we know today Broadcasting has its roots in Marconi’s success-ful demonstration of radio communications across the Atlantic in 1901 Radio broadcastingbecame established during the 1920s, and TV started appearing shortly after John Logie Baird’sdemonstration of an electromechanical television in 1926 In 1928, American inventor PhiloTaylor Farnsworth gave the first public demonstration of an all-electronic scanning televisionsystem [3] He was awarded a string of patents, which he later licensed to RCA, which became

a giant in the world of TV and radio The 1950s, 1960s and 1970s witnessed an extensivedevelopment of colour television and recording, and the first portable audio products.The mobile telephone has its origins in Motorola’s radiotelephone of 1946 The first auto-mated cellular systems were NTT’s in Tokyo in 1979 and the NMT network introduced inSweden and Norway in 1981 The AMPS system was introduced in the USA in 1983 andthe DynaTAC handheld cellular phone was introduced by Motorola, considered to be thefirst ever handheld phone and now recognisable instantly as the “brick phone” GSM phoneswere introduced in 1991 – a digital system with greatly enhanced speech quality Althoughpersonal computers were available about a decade before, GSM phones were one of the firstconsumer products that used digital electronics to perform real-time processing of signals.The 1990s can therefore be considered (debatably) the start of the digital consumer productrevolution, with the DVD player (1996) and portable MP3 player (1998) appearing in thesame decade The iPhone was launched in 2007 and, in the short time since, smartphones andtablets have become an almost indispensable part of modern living, being most people’s mainportal to the internet, with awesome functionality that includes multi-band cellular and inter-net connectivity, voice-directed navigation, multimedia playback, games, augmented reality,and so on

1.2 The Electromagnetic Spectrum

Electromagnetic waves are vital to almost all communications systems and modern consumerproducts Radio waves, infrared, visible light, ultraviolet (UV) radiation and X-rays are allforms of the same phenomenon of electromagnetic wave propagation Some of the mostimportant frequency bands and applications of the electromagnetic spectrum are shown inFigure 1.3 This is, once again, on a logarithmic scale: X-rays have a frequency around abillion times the frequency of a mobile phone radio signal Of course, not all these frequenciescan be generated easily (if at all) by conventional transistor-based electronics High-powermicrowaves, for example, are generated in a magnetron for some applications Light, foroptical storage and communications, is generated by a laser

Some of the most common frequencies and applications are listed in Table 1.1 Wavelength(𝜆) is inversely proportional to frequency and, assuming free space propagation, the relation-

ship c = f 𝜆 can be used, where c is the speed of light in vacuo (3 × 108m s−1) For radio

Satcomms Radar

Microwave oven Wi-Fi Mobile phones Radio

Medical X-rays

Radioactivity

Optical Fibre comms

Figure 1.3 Frequency, wavelength and terminology for various applications of electromagnetic waves

Table 1.1 Example frequencies of some common systems

400 GHz are already starting to be allocated to new systems, as the lower frequencies becomecongested In addition to communications, the radio spectrum has slots allocated for otheruses, such as radar, navigation, radio astronomy and remote-sensing Remote-sensing is veryimportant for the environmental monitoring of problems such as the hole in the ozone layer andthe destruction of tropical rainforests, while microwave systems are very important because

of the need to penetrate cloud cover

A key principle in radio communications is that antennas, which convert electrical currentsinto radio waves (or vice versa), need to be of a size comparable to a wavelength This,essentially, is why high-frequency signals are used for wireless communications – the antennasmust be of a practical size In all cases, the choice of operating frequency is governed by a range

of factors, including bandwidth and range required, transmitter power available, propagationloss, antenna gain, cost of the equipment and licensing The gain of an antenna is a figure

of merit that describes how effectively it concentrates power into a desired direction, that is,towards the receiver(s) A perfect omnidirectional antenna spreads power out equally in alldirections, as illustrated in Figure 1.4(a), and has a gain of 0 dBi (dBi = decibels relative to the

isotropic case) For an idealised point source transmitter, the power would be equally distributed

over the area of a sphere (4𝜋r2, where r is the distance from the transmitter) giving rise to what is known as spreading loss, with signal strength falling as 1/r2 Even in a broadcastingapplication, such as terrestrial TV, if the transmitter really had an omnidirectional antenna likethis, a great deal of its precious RF power would be radiated upwards into space and wasted

Figure 1.4 (a) Idealised point source transmitter giving omnidirectional coverage (b) Doughnut-shapedradiation pattern from a typical terrestrial transmitter (c) Pencil beam from a satellite dish

0.01

0.1

1 10

57-63 GHz

O2118.74 GHz

Frequency / GHz, log scale

Figure 1.5 Trend of atmospheric attenuation at sea level; see Ref [4] for data

Hence, the antenna is designed to concentrate its power in the directions where it is needed –typically the radiation pattern would be doughnut-shaped for a terrestrial TV transmitter, asillustrated in Figure 1.4(b) For direct line-of-sight communications, a parabolic dish has a

‘pencil beam’ radiation pattern approximately 2–5 degrees wide, as illustrated in Figure 1.4(c),and has high gain of the order 35–40 dBi Antennas are passive, reciprocal, devices and if anomnidirectional antenna is used for a receiver it will pick up signals equally from all directions,including noise and interference, and so the receiver’s antenna gain is equally important.High-gain antennas are many wavelengths in size, so at low frequencies a high-gain antennamay be unfeasibly large On the other hand, whilst high-gain antennas are physically small

at high frequencies, the propagation loss starts to become more of a problem Figure 1.5shows a plot of the atmospheric attenuation (dB km−1) at sea level of a signal [4] The loss isdominated by the effects of water vapour and oxygen: water vapour causes the steady increase

in loss as frequency increases, as well as peaks at 22.3, 183.3 and 323.8 and 380.2 GHz due

to rotational modes of the asymmetric H2O molecule; oxygen absorption causes the peak

at 60 GHz (which actually is formed from a number of lines between 57 and 63 GHz) and

a clear line at 118.74 GHz A further complication is the need to consider the intermittentattenuation caused by rain, fog, clouds and dust, particularly at frequencies beyond 10 GHz.For communication that is not line-of-sight, it is also necessary to account for attenuation andblocking due to natural and man-made obstacles – in those situations, low frequencies give

a diffraction advantage This is sea-level data and the atmosphere actually has a number ofdistinct layers In mobile systems, the propagation characteristics can change rapidly with time,and the Doppler effect needs to be accounted for in the case of moving vehicles Propagationeffects are a highly complex issue that is covered in more depth in Chapter 14

1.2.1 Spectrum Licensing and Standards

In order to prevent different users interfering with one another, the use of the radio spectrum

is carefully regulated by government agencies (such as the FCC in the USA and OFCOM in

Bluetooth class 2

ZigBee 802.15.4

5G2G

Figure 1.6 Various wireless communications standards compared

the UK) and international bodies such as the International Telecommunications Union (ITU).These bodies issue licences to bona fide users, seek out unauthorised users, and conductextensive consultations with stakeholders before allocating new frequency bands There aremany different types of licence, depending on the transmission frequency and application.Frequency allocation charts are available to download, and the number of different bandsthat have been allocated for diverse purposes is amazing Wallcharts of ITU allocations areavailable (e.g., www.cedmagazine.com has a free pdf file) but there are so many allocationsthat the chart would be unreadable if reproduced here

To ensure that radio equipment and consumer products are compatible, there is a tirelesseffort by standards committees to define the hardware and software specifications for differentapplications Modern communications systems are so sophisticated that these documents run tohundreds and hundreds of pages The Institute of Electrical and Electronics Engineers (IEEE)standards are particularly important; for example, the IEEE 802.11 wireless LAN standardswere key to the rapid adoption of Wi-Fi around the world Figure 1.6 shows various IEEE andother wireless communications standards compared on a range versus data rate graph

1.3 Industry Trends

A general background to the electronics industry as a whole is important in the study of modernwireless communications systems At the heart of the industry’s success is nanometre-scalesilicon technology, particularly CMOS technology, capable of realising sophisticated system-on-chip products In addition to this, many microwave and millimetre-wave systems, and thephotonic systems that make up the core network, require specialist compound semiconductordevices such as GaAs, GaN and InP devices This has led to a great deal of research anddevelopment in the area of miniature systems integration, including multi-chip modules,system-in-package and antenna-in-package techniques (these are described in Chapter 16).Silicon and SiGe technology has started to challenge many of the traditional III–V marketsand is rapidly opening-up the millimetre-wave part of the spectrum for consumer applicationssuch as 60 GHz wireless networks

The microwave industry has changed dramatically as consumer-oriented products such ascellular mobile, Wi-Fi, Bluetooth and GPS systems, amongst others, have become mainstream.The volume of this side of the industry is absolutely vast; for example, one billion Androidsmartphones and nearly 200 million iPhones were sold in 2014 This immense scale haschanged the way the industry operates To be a world leader, a company must have theresources to meet this huge demand Typical silicon fabs with state-of-art capability cost morethan US$3 Bn, while a large display factory, required to process 30 000 glass panels per month,each as large as 2 × 3 metres, typically requires an investment of US$5 Bn Such a factorywill require exceptionally good supply chain management, and often suppliers will be housedon-site in order to keep things running smoothly The scale of mass production of consumerelectronics in China is well known, and there are already signs of the industry entering a newphase of globalisation For example, at the time of writing Foxconn was planning to invest in

12 new assembly factories in India, potentially creating one million jobs

This immense scale of the consumer electronics industry, which drives a great deal ofmicrowave and millimetre-wave development, has led to new ways of the industry buildingcritical mass, including IP licensing, joint ventures, alliances, mergers and acquisitions For-tunately, the industry has largely learned the importance of cooperation on wireless standards,with bodies such as the 3GPP, IEEE and ITU playing a vital role Electronics is already foundalmost everywhere and has transformed our lives in many ways, and yet there is a furtherrevolution underway in 5G+ communications, the internet of things, machine-to-machinecommunications, augmented reality and telepresence, to name a few Without standards, thevision of everything being connected seamlessly to the Cloud will not be achievable

The scale of the industry and the spectacular pace of change have given tremendous tance to intellectual property and branding The value of a brand has become more andmore about the user experience and even emotional attachment and loyalty This has dra-matically increased the importance of industrial product design and consideration to thehuman–computer interface The style and ergonomics of the product are often a key differen-tiator in the market place, since the electronics inside is comparable The skill of the productdesigners lies in exploiting new materials and manufacturing processes to create a stylishdesign that is economical to produce Design-for-manufacture (DFM) and design for the envi-ronment (DFE) are important themes of this activity As consumer products are replaced soquickly, designers need to consider how the whole ensemble of electronic and mechanicalcomponents can be assembled quickly, for low production costs, and later disassembled forthe efficient recycling of key parts and materials Electronic waste and protecting the environ-ment are areas where government legislation is crucial to the long-term sustainability of theindustry

impor-1.3.1 The Multidisciplinary Nature of Modern RF Engineering

A state-of-the-art integrated circuit is more complex than the whole US road network It isnot difficult to justify the claim, therefore, that electronic engineering is one of the mostchallenging careers of all, and engineers have to cope with exceptionally rapid technologicalchange But at the same time, it is also one of the most exciting and fulfilling careers – one

only needs to read IEEE Spectrum regularly to know that electronic engineers are capable of

amazing feats of technology that can dramatically improve our lives through impact in thefields of healthcare, energy, communications, transport, science and space exploration

Introduction 9

Analogue Circuits

Transmission Lines

Embedded Systems C/C++

Comms

Electromagnetism Semiconductor

Devices

Microelectronic Packaging

Figure 1.7 Aspects of modern RF engineering

Microwave and millimetre-wave engineering was, for many years, a niche area in the realm

of electromagnetics, transmission lines and the Smith chart, sometimes unfairly referred to as

a ‘black art’ As digital techniques have advanced, the RF engineer has needed to develop amuch wider range of skills, as illustrated in Figure 1.7, with at least a basic understanding oftopics from semiconductor physics through to digital electronics:

Semiconductor Physics:RF engineering uses some of the most advanced conductor and quantum devices, because achieving low noise and high power atthese frequencies is highly challenging and often beyond the capability of regu-lar devices RF engineers need, therefore, to be conversant with the underlyingphysics in the device to make informed design choices

semi-Analogue circuit design:Twenty years ago, a monolithic microwave integratedcircuit (MMIC) amplifier could be designed with two transistors and a few induc-tors and capacitors to match the transistors to 50 Ω Now, the radiofrequencyintegrated circuit (RFIC) designer has to make use of the full range of ana-logue circuit design skills to reduce current consumption and chip area, andrealise complex circuits and subsystems with adaptive control loops to maximiseperformance

Microelectronics and packaging:The integration of high-frequency analogueand digital circuits has pushed integration levels and packaging technology to newextremes Twenty years ago, RF designers might be using single transistor die-mounted onto specialist substrates Nowadays, they are more likely to encounter3600-pin ball-grid array (BGA) packages that have pushed printed circuit boardand assembly technologies to the limit

Digital communications:The close integration of digital signal processing (DSP)with RF transceivers makes it impossible to work effectively in a team without

an understanding of IQ modulation, orthogonal frequency division multiplexing(OFDM), sigma-delta modulators, and so forth For example, power amplifiersneed to be designed to cope with complex varying-envelope signals that max-imise spectral efficiency; they cannot be designed in isolation from the digitalcommunications engineers

Embedded systems design:Modern RF transceivers use extensive digital controlfor a range of functions Without the ability to programme in C or a similarlanguage, the RF engineer will be unable to get a chip-set evaluation board or (forexample) a ready-made ZigBee or Bluetooth module to work.

1.3.2 Business Matters

The electronics business is extremely competitive; customers demand better and better productsevery year and expect the price to fall The need for standardisation sometimes makes itdifficult to introduce a new product without extensive industry-wide consultations; formatwars such as VHS versus Betamax, Blu-Ray versus HD-DVD, and 8 mm versus VHS-C can

be extremely costly and damaging Competing companies might lower their prices below aneconomically viable level to encourage consumers to adopt their standard But sooner or laterthere have to be winners and losers, and sometimes it is the technically superior technology thatloses Fortunately, with wireless communications standards there is some government controlbecause of spectrum regulation: Thanks to the tireless efforts of engineers on committees,there is a high degree of standardisation However, this is never a straightforward process aslicensing fees for crucial patented technologies might require extensive negotiation

Whilst consumer electronics is a very competitive business, it can also be extremely itable In 2014, the top ten consumer electronics companies were, in alphabetical order; Apple,Canon, Hitachi, HP, Nokia, Panasonic, Philips, Samsung, Sony and Western Digital The topfive smartphone brands were Samsung, Apple, Xiaomi, Lenovo and LG Apple, the mostvaluable brand in the world at the time of writing, had sales of US$ 183 Bn and a net income

prof-of almost US$ 40 Bn in 2014 [5] There are other familiar brands, such as Motorola, Dell, LG,Pioneer, Sanyo, Sharp and Toshiba Some companies are well-known as IC suppliers, includ-ing Intel, AMD, Qualcomm, TI, MediaTek, Hynix, Micron, ST, Broadcom, Renesas, Infineon,NXP, Nvidia, Fujitsu and Qorvo Some of these companies do not actually fabricate any ICs,but there are a number of other companies, including TSMC, UMC, GlobalFoundries andSMIC, which specialise only in fabricating ICs for customers There are many big companies(e.g., Foxconn, Pegatron and Flextronics) that focus on carrying out electronics manufacturingfor the aforementioned global-brand companies There are many other companies, includingInventec, Quanta Computer, Compal, Elite, WKK and Wistron, that design and manufactureproducts which are then badged by other companies with their own branding for retail There

is an increasing trend for companies based in China and South East Asia to develop their ownbrand in the retail market place, with companies including Huawei, ZTE, Lenovo, HTC, Haier,Changhong, TCL, Asus, Panda Electronics, Ningbo Bird, Skyworth, Amoi, SVA, Xiaomi andBenQ amongst those leading the way What all this highlights is the fact that the global elec-tronics industry is vast (it is estimated to be worth US$ 600 Bn per annum) and relies on anumber of different business models, forming a sophisticated network:

Vertically integrated company:The model where a large company makes thing from the semiconductor devices to the branded consumer products

every-Contract manufacturer (EMS):A company that concentrates solely on ing an electronics manufacturing service for its customers

provid-Introduction 11

OEM:There are three meanings in use, but in the context used here an nal equipment manufacturer produces its own branded products which includecomponents and sub-assemblies from other companies

origi-ODM:An original design manufacturer designs and manufactures a product that isthen sold under another brand name; this is often referred to as ‘badge engineering’

Chip manufacturer:A company that specialises in designing sophisticated value ICs and manufactures them for sale as components

high-Foundry:A company that carries out semiconductor manufacturing for customersbut does not design products of its own

Fabless design house:A company that specialises in designing ICs and suppliesthem as components, but subcontracts out the chip manufacture to a foundry

Chipless design house:A company that has design techniques that are sufficientlynovel for other companies to want to pay to use them in their own chip designs.The UK-based company ARMTMis a good example of this; ARM’s processorsare used in a vast number of consumer products but they supply the design IP,which is then integrated within a larger system-on-chip by the customer

Material, component and sub-assembly suppliers:Companies that specialise

in supplying into the businesses that manufacture electronic products Sometimesthese are household names due to the breadth of their activities (e.g., BASF, 3M,Corning and DuPont), but usually these suppliers operate entirely on a business-to-business (b2b) basis and are not well known outside the industry

Distributor:With a vast range of products available, distributors provide a keyintermediary service between suppliers and customers, giving a broad productportfolio, independent advice and technical support

Value-added reseller:In the context used here, this model refers to a systemsintegrator that takes wireless equipment and combines it with other hardwareand software to provide a high-level product solution With mobile and wirelesssystems having a profound impact in new areas such as retail, commerce and thecreative industries, this is a valuable service for companies that do not wish tobecome involved in technical details but instead want a turn-key solution for theirbusiness needs

These categories are well known for the general electronics industry, whilst in the specificcase of the telecommunications industry there are additional company categories relating tothe manufacture, installation, operation and marketing of the internet and telephone networks.The internet itself, comprised of a huge conglomeration of networks, is operated by a variety

of telecommunications companies at the core and access network levels Mobile network ators (or carriers) own specific cellular network infrastructure and offer services to customers.There are also virtual network operators that buy air time in bulk and sell packages with adistinct retail brand At another level there are internet-focused companies such as internetservice providers and major web site companies, such as social media sites, that operate

oper-numerous large data centres in order to meet the demands of more than a billion customers insome cases.

1.4 Forms of Wireless Communication

A wide variety of forms of wireless communication has evolved since the first demonstration ofwireless telegraphy by Guglielmo Marconi [6] In terms of purpose and physical location of theterminals, wireless links can be classified as point-to-point, point-to-multipoint, broadcasting,

or mesh networks In the following sections, some of the key distinct types of communicationssystems are described, chosen as examples of the main approaches for wireless communication

1.4.1 Terrestrial Television

All around the world, the analogue TV system has had to make way for digital systems.The analogue TV standards, NTSC (National Television System Committee), PAL (PhaseAlternating Line) and SECAM (S´equentiel couleur `a m´emoire) are rapidly being confined

to history Digital TV makes use of powerful video compression as well as sophisticatedmodulation and coding schemes to reduce the bandwidth of the transmitted signal Standard-definition digital TV signals actually occupy a similar bandwidth to the previous analoguesystems (e.g., around 8 MHz bandwidth for PAL) A fair question is, then: why go to all thistrouble, when the analogue system had been working very well for around 70 years?

The need to move to digital signals to transmit more TV channels was dictated by analoguesignals being sensitive to propagation effects and interference With the power density of the

radiated wave falling off as 1/r2, a simple calculation shows that in theory a single transmitterantenna could comfortably cover the whole of the UK or a typical State of the US However,

the curvature of the earth means that there is a radio horizon which is determined by the height

of the transmitter (TX) and receiver (RX) antennas and the radius of the earth This is given by

√

17h km [7], where h is the effective antenna height in metres This is why the transmitters

are mounted on tall towers and situated on hills where possible A 300-metre transmitter heightgives around 70 km radio horizon, so the Crystal Palace transmitter, for example, serves all ofLondon The Crystal Palace transmitter’s effective isotropic radiated power (EIRP) is of theorder of one megaWatt The actual power output is less than this, but it is the effective value,which takes into account the transmitter antenna’s gain, that determines the signal strength atthe TV receiver antenna

Figure 1.8 shows a stylised map of the main transmitter sites in the UK for UHF TV Thereare many other, smaller transmitters or repeaters required to fill in gaps in the coverage thatare caused by blocking of hills and buildings For example, in the London area alone there areabout 50 low-power transmitters in addition to the main Crystal Palace one With analoguesignals, receivers are very sensitive to interference; ‘ghosting’ is a clear visual indication inanalogue TV of how a receiver is affected when it receives two components of the samesignal from different paths The ghosting is caused by the small but noticeable difference inthe time that it takes each signal component to reach the receiver To avoid this interference,with analogue TV it is necessary to ensure that adjacent transmitters use different radio carrierfrequencies The frequency allocations and the coverage must be carefully planned In theUHF band, some diffraction occurs around buildings and even around the tops of hills because

Introduction 13

Figure 1.8 The UK’s main terrestrial TV transmitter sites

of the fairly long wavelength of the signal (500 MHz in free space gives 0.6 metre wavelength)but, even so, repeaters are used to fill in poor coverage areas such as valleys where the maintransmitter signals cannot reach The signals from a non-adjacent transmitter with differentcoverage area can be on the same frequency because of the physical separation; normally,the signals simply do not reach far enough to interfere However, sometimes the atmospheric

conditions can make a signal travel further than normal by refracting (bending) it past thenormal horizon Then, non-adjacent transmitters can interfere; for example, in Kent (in theSouth East of England) it was sometimes possible to receive TV signals from Belgium inunusual weather conditions.

The need to use many different frequencies in the analogue system to avoid interference,unfortunately, leads to a very inefficient use of the precious UHF spectrum This is the mainreason why digital TV is now dominant As an indication of how much more efficient thedigital TV system is, note that in the UK there were only five terrestrial analogue TV stations,even after many years of technical development: however, within a few years of its introduction

to the UK, digital terrestrial TV offered more than 50 stations, even before the analogue systemwas switched off

1.4.1.1 Digital Terrestrial TV Formats

On December 11, 2006, the Netherlands became the first country to switch off analogue andmove entirely to digital TV broadcasting The number-one advantage of digital TV is thatmore channels are possible, but making this happen is a major feat The first step is to usevideo data compression standards such as MPEG-2 The second key technology involves thehighly advanced coding and modulation techniques that are used There are four major digitalterrestrial TV standards around the world at the time of writing, with the following maindeployments:

ATSC: Advanced Television Standards Committee

USA, Canada, Mexico, South Korea

The main terrestrial version of this standard uses a modulation scheme called8-VSB (vestigial sideband), which is an advanced form of ASK, using eight levels

of amplitude and spectrum shaping to achieve high spectral efficiency

DVB-T: Digital Video Broadcasting (Terrestrial)

Europe, Russia, Africa, India and Asia, Australia

DVB allows for a range of different signal formats for different broadcastingsystems: e.g DVB-S for satellite, DVB-C for cable, DVB-H for handhelds

ISDB: Integrated Services Digital Broadcasting

Japan, South America, Botswana, Philippines

DTMB: Digital Terrestrial Multimedia Broadcast

China, Hong Kong, Macau

DVB-T, like many other wireless communication standards, uses orthogonal frequencydivision multiplexing (OFDM) The purpose of OFDM is to combat the effects of multipathpropagation Figure 1.9 illustrates, simplistically, how multipath propagation leads to spreading

of the data signal, placing a limit on the maximum data rate because of inter-symbol interference(ISI) In practice, there will rarely be just a few distinct signal components, and it is necessary

to analyse the channel statistically and refer to a more continuous effect of delay spread In

OFDM, the digital data is split up and sent in parallel using a closely packed block of thousands

of RF carriers, each with a much lower individual data rate, as shown in Figure 1.10 This type