The book you’re holding, physically or electronically, is the result of a very
interesting, challenging but also rewarding research project. The research was
carried out in different contexts and cooperations but it was centered around the
following question: how can we make the RF transmitters of our modern com-
munication systems (WiFi, GSM, LTE, and so on) more flexible and more efficient
at the same time.
OSCILLATORS are key building blocks in integrated transceivers. In wired and
wireless communication terminals, the receiver front-end selects, amplifies and
converts the desired high-frequency signal to baseband. At baseband the signal can
then be converted into the digital domain for further data processing and demodula-
tion. The transmitter front-end converts an analog baseband signal to a suitable high-
frequency signal that can be transmitted over the wired or wireless channel.
This book presents millimeter wave communication system design and analysis at the
level to produce an understanding of the interaction between a wireless system and its
front end so that the overall performance can be predicted. Gigabit wireless commu-
nications require a considerable amount of bandwidth, which can be supported by
millimeter waves. Millimeter wave technology has come of age, and at the time of
writing the standards of IEEE 802.15.3c, WiGig, Wireless HD TM , and the European
Computer Manufacturers Association have recently been finalized.
In recent years, the research and developments in the area of RF and microwave
technologies have progressed significantly due to the growing demand for applica-
bility in wireless communication technologies. Starting from 1992, wireless com-
munication technologies have become quite mature. In the modern era of electronic
developments, design of wireless handsets is an example of integration of many di-
verse skill sets. Classical books in the areas of microwave technology provide us
with an in-depth knowledge of electromagnetic fundamentals.
Ultra-wideband (UWB) technology enables high data-rate short-range communica-
tion, in excess of hundredmegabit-per-secondsand up to multi-gigabit-per-seconds,
over a wide spectrum of frequencies, while keeping power consumption at low lev-
els. This low power operation results in a less-interfering co-existence with other
existed communication technologies (e.g., UNII bands).
In addition to carrying a huge amount of data over a distance of up to 230 feet
at very low power (less than 0.5mW), the UWB signal has the ability to penetrate
through the doors and other obstacles that tend to reflect signals at more limited
bandwidths and higher power densities.
The first practical examples of mobile communications were used in many countries like
the USA, the UK and Germany in military services, and played a significant role in the
First World War to transfer important information from the front to headquarters to take
further actions. Good and secure wireless communications were an important need for all
military services – army, navy and air force. In this respect, the Second World War was a big
experimental battlefield for the development and evolution of mobile radio. It was in the
interests of governments that after the Second World War the military investment should
be paid back by civilian use, and all western European countries started their so-called first
generation of mobile communication networks.
Wirelesscommunications,especiallyinitsmobileform,hasbroughtusthefreedomofmobility
andhaschangedthelifestylesofmodernpeople.Waitingatafixedlocationtoreceiveormakea
phone call, or sitting in front of a personal computer to send an e-mail or download a video
program, has become an old story. Nowadays it is commonplace for people to talk over a cell
phonewhilewalkingonthestreet,ortodownloadandwatchamoviewhiletravelingonatrain.
Thisisthebenefitmadeavailabletousbythesuccessfulevolutionofwirelesscommunications
over three generations, with the fourth generation being under way.
Over many years, RF-MEMS have been a hot topic in research at the technology
and device level. In particular, various kinds of mechanical Si-MEMS resonators
and piezoelectric BAW (bulk acoustic wave) resonators have been developed. The
BAW technology has made its way to commercial products for passive RF filters,
in particular for duplexers in RF transceiver front ends for cellular communica-
tions. Beyond their use in filters, micromachined resonators can also be used in
conjunction with active devices in innovative circuits and architectures.
