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Limitations of existing receivers are the reason for
the search for flexible receiver architectures. It is
clear that the world of wireless communication systems
and radar sensors will be heterogeneous in the future.
Therefore arises the need for hardware solutions, which
can handle several standards and related software implementations.
Sampling architectures which sample the RF signal close
to the antenna can provide a very flexible approach.
The specifications for the analogue to digital converter
at millimeter wave frequencies are at the moment prohibitive
for the realization of a communication or high resolution
sensor system. Using a bandpass limited subsampling
approach it is however possible, to investigate the
basic feasibility of a Sigma-Delta modulator approach
at a carrier frequency of 24 GHz.
The six-port concept relies on an increased number
of scalar measurments of the received signal and is
basically suited for broadband applications. The signal
is fed into power dividers, super-positioned with a
reference signal and the amplitude is measured at more
than 3 ports. A higher number of ports will increase
the accuracy, but there is an optimum of ports with
respect to the signal to noise ratio of the receiver.
Flexible signal generation will gain of importance
if different communication standards have to be supported
(e.g. IEEE 802.11 b, a, x ...). With Direct Digital
Synthesizers frequencies up to 2 GHz may now be reached.
Different modulation schemes may be implemented in Field
Programmable Gate Arrays in order to support the required
standards.
Biography
Johann-Friedrich Luy received the Dipl.Ing. degree
for his investigations on heat conduction in semiconductor
lasers and the Dr.-Ing. degree for his thesis on the
first silicon MBE made IMPATT diodes from the Technical
University of Munich, Germany in 1983 and 1988, respectively.
Between 1989 and 1996 he has been engaged in research
on Si/SiGe millimeter wave devices and circuits („SIMMWICS“).
Since 1996 he is head of the Microwave Department, DaimlerChrysler
Research Center, Ulm, Germany. The development and application
of short range communication links, research in the
field of software configurable telematic platforms (software
defined radio) and in the area of radio location techniques
is the main focus of his interest.
He has authored and co-authored over 50 papers in referred
journals and symposia proceedings. He was co-editor
of Silicon Based Mm-Wave Devices (Berlin/New York: Springer
Verlag 1994) and Distinguished Lecturer of the IEEE
Electron Devices Society in 1996/1997. He is a lecturer
and supervisor at the Technical University of Munich
and Hamburg.
Dr. Luy is an URSI member and an IEEE Fellow of the
MTT society (Jan. 2000), member of the TPC board of
the International Microwave Symposium, of the editorial
board of the Microwave Theory and Transactions as well
as other referred journals and an appointed member of
the EDS Compound Semiconductor Devices and Circuits
Technical Committee.
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