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Emeritus Distinguished Microwave Lecturers

DMLs serve a three-year term.  Lecturers whose terms have just expired become Lecturers Emeritus

for one year and are still available for engagement via the MTT Speakers Bureau. The topics and abstracts for previous

Current DMLs can be found here.

Lecturers Emeritus 2012

Frank Ellinger

Term Ended 2011

Dresden University of Technology

Head of Chair for Circuit Design and

Network Theory

Barkhausenbau 119, Helmholtzstrasse 18, 01069 Dresden, Germany

Tel: +49/351/46338735

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homepage: http://ccn.et.tu-dresden.de

Radio Frequency Integrated Circuits for Adaptive Beamforming

By means of adaptive antenna combining the tradeoff between coverage range, reliability, data speed and power consumption can be improved in wireless systems. By smart weighting of the phases and amplitudes of multiple antenna signals, the antenna gain can be increased and intersymbol interferences can be reduced. Most systems perform the vector weighting of the antenna signals in the baseband. Since multiple circuit paths are required from RF to baseband, the resulting power consumption and costs are very high.

These drawbacks can be mitigated by performing the adaptive combining in the radio front-end. In this case, only one path from IF to baseband is required. To reduce the control complexity, the phase shifters should vary the phase without manipulating the gain, and the gain control components should adjust the gain without changing the phase. However, if we e.g. vary the transconductance or the load resistance in amplifiers for gain control, the RC time constants of the transistors change leading to significant undesired phase variations. Further challenges such as integration into silicon, sufficient bandwidth, good large signal properties, low power consumption and compact size have to be considered.

In this lecture, these challenges are addressed and solutions are proposed. Different architectures are compared performing the adaptive combining in the RF, LO and IF sections. Several concepts implemented in both CMOS and III/V technologies are presented. The compact and fully integrated circuits are optimized for high speed applications operating in accordance to the 802.11a/n standard at C-band. Detailed theoretical studies are made enhancing circuit understanding and enabling efficient optimizations.

Phase compensation techniques in variable gain amplifiers and topologies mitigating phase variations by using RC and biasing dummy paths are demonstrated. These topologies are compared with passive attenuator based approaches.

A variety of different active and passive phase shifter RFICs based on vector modulators, varactor tuned transmission lines, reflection-type phase shifters with multiple parallel reflection loads, etc. are discussed and compared.

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Fadhel Ghannouchi

Term Ended 2011

Fellow IEEE and Fellow IET

CORE Professor and Senior Canada Research Chair,

Director, iRadio Laboratory (www.ucalgary.ca)

Department of Electrical and Computer Engineering Schulich School of Engineering,

University of Calgary, Canada

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SDR Based Power amplifiers /Transmitters for Advanced Wireless and Satellite Communications

The next wave in the information revolution will consist of bringing intelligence to the information and communication technology (ICT) sector, allowing seamless and intelligent networking and communication between different users using different services and operators. This will lead to the convergence of communication technologies, aiming at the development and deployment of cooperative and ubiquitous networks that involve existing and future wireless and satellite communications systems.

A critical element in enabling the convergence of different communication systems is the development of software defined radio (SDR) systems that can be used across different frequency bands and for multi-standard applications. This SDR has to be developed to support different frequency carriers and modulations schemes concurrently, in addition to being power- and spectrum-efficient, in order to be able handle high data rates, while being less energy-hungry and more environmentally friendly.

The design of power amplifiers as critical components in any SRD based communication terminal has to be considered closely together with the system architecture, in order to ensure optimal system level performances in terms of linearity and power efficiency. This implies the use of adequate transmitter architectures that convert the analog baseband information to architecture dependent amplifier driving signals, such as sigma-delta, EE&R, Polar and LINC architectures. This talk lays out the principles behind SDR systems and examines the design of software-enabled linear and highly efficient RF/DSP co-designed power amplifiers/transmitters for multi-standard and multi-band applications. Recent advances and practical realizations will also be presented and discussed.

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Ke Wu

Term Ended 2011

Canada Research Chair in RF and Millimeter-Wave Engineering

Poly-Grames Research Center

Department of Electrical Engineering

Center for Radiofrequency Electronics Research (CREER) of Quebec

Ecole Polytechnique (University of Montreal)

M-6021, Pavillon Lassonde

Ecole Polytechnique

2500 Chemin de Polytechnique

Montreal, Quebec, Canada H3T 1J4

Tel : 1-514-340-4711 ext. 5991

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Substrate Integrated Circuits (SICs) for Microwave and Millimeter-Wave Systems and Applications

Widespread applications and commercial success of future GHz and THz electronic and photonic devices and systems including RF, microwaves and millimeter-waves are closely related to their manufacturing cost and circuit integration. Our proposed integration technologies of planar and non-planar structures as well as related new progress indicate that the emerging substrate integrated circuits (SICs) are able to provide unprecedented advantages for developing low-cost GHz/THz components, systems and wireless photonic applications. This talk reviews the state-of-the-art and underlying features of the proposed integration platforms for designing the next generation RF and millimeter-wave ICs and systems. Challenging issues and future directions are discussed for research and developments. Potential problems and possible solutions are also presented. It is believed that the newly proposed concept of SICs will offer a potentially cost-effective and performance-promising solution for mass commercial applications. With the development of innovative fabrication processes and material synthesis techniques, unique hybrid and monolithic high-density 3-D integration of planar and non-planar structures (or system-on-substrate approach) become realizable. It can also be demonstrated that this scheme of SICs effectively bridges the gap between electronics and photonics. In this presentation, our current research activities and future RF and millimeter-wave research directions will also be discussed.

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