Professor Paul J Tasker

Overview

Prof. Paul J Tasker joined Cardiff University in 1995. His research addresses the problems encountered in the field of non-linear RF and microwave circuit design. These activities have, to date, focused mainly on the design, modelling and characterisation of non-linear RF and microwave transistors and power amplifier circuits.

Linear and efficient power amplifiers are a critical component in present and future communication, satellite and wireless systems. The group has unique facilities for performing, high frequency (up to 40 GHz) and high power level (up to 100 Watts) time domain based I-V waveform measurements, non-linear vector network analyser concept, on transistors and circuits into user defined source and load impedances, active harmonic load-pull concept. This experimental work is supported by a number of CAD based software tools.

This research has been performed with the support and collaboration of a number of leading international companies, for example, Nokia, Filtronics, Agilent, Motorola, Celeritek and Marconi.

After completing his secondary education in Castletown, Isle of Man in 1976, Paul Tasker went to study Physics and Electronics at the University of Leeds, obtaining a Combined Studies BSc Degree with First Class Honours in 1979.  He remained at Leeds University, obtaining a PhD from the Department of Electrical and Electronic Engineering in December 1983.  Prior to his present appointment he was a Senior Research Associate at Cornell University, Ithaca, NY, USA and then a project manager at the Fraunhofer Institute for Applied Solid State Physics (IAF), Freiburg, Germany.  At Cornell University he managed a world-leading research programme in the area of fabrication, design, characterisation (DC and microwave) and modelling (analytical and numerical) of compound semiconductor devices.  Key outcomes of this work were (i) the demonstration of low noise operation in MODFETs at cryogenic temperatures; (ii) the development of very high performance (fT > 150 GHz) pseudomorphic transistors; and (iii) the demonstration of a laser diode that was “on-wafer” testable with microwave probes.  At the IAF he established and managed research programs responsible for (i) the development, characterisation and optimisation of short gate length compound semiconductor devices and (ii) the development, design and characterisation of high power microwave MMICs and low noise millimeter-wave MMICs.  An outcome of this work was the development of a comprehensive millimeter-wave characterisation facility, the realisation of state-of-the-art millimeter-wave MMICs having 20 dB Gain @ 115 GHz and laser diodes with a 40 GHz 3dB modulation bandwidth.

Paul Tasker has expertise in the area of fabrication, design and characterisation of high frequency (microwave and millimeter wave) compound semiconductor electronic and optoelectronic devices and circuits.  He has developed a number of microwave and millimeter wave, s-parameters, noise parameters and non-linear parameter, measurement systems along with the associated analysis and extraction techniques for characterising transistors and developing CAD models.  As a consequence of this work he has contributed to over 100 technical papers and publications including two book chapters.

He has lectured at a number of short courses and workshops both in Europe and the USA on transistor design, optimisation and characterisation. He has acted as a consultant to various major USA industries, GE, MSC, AT&T Bell Laboratories, Alpha, Martin Marietta, Siemens, NESI, EG&G Princeton Applied Research and Hewlett Packard.