© Skyarna Ltd 2012

Dr J. Powell, MIET

Jeff has more than 18 years experience in microwave engineering; including many successful MMIC designs comprising diverse circuit functions using a wide range of circuit technologies.  He has also designed circuit packaging, consulted on significant procurement programmes and maintained an active role in research oriented ‘leading edge’ technology demonstrations.

After graduating Jeff worked as a post doctoral research fellow then assistant lecturer in microwave engineering and electromagnetic theory. Following this he has worked for a leading defence contractor and a tier one automotive component manufacturer.  Jeff has published widely in the literature and has co-authored several patent applications.

His work in the last 5 years has included the following:

• Lead engineer/designer for an integrated MMIC chipset for a mm-wave transceiver.  This chipset was designed to support channelised, spectrally efficient digital communications.  Multilayer low cost packaging was used to complete the RF subsystem, which formed part of a complete point-to-point radio link operating at 65 GHz.
• E-band MMIC LNA and power amplifier design on the WIN PP10 process.
• Demonstration of class J amplifier MMICs at X-band with Cardiff University.  Novel amplifier modes were used to demonstrate optimum power and efficiencies over >30% bandwidths.  This project used advanced polyharmonic device model formulations based on multiple harmonic load-pull measurements made in the Cardiff Group.
• RF lead for circuit designs using a proprietary GaN MMIC technology including process characterisation and design kit compilation.  Including the design of masksets for passive and active element characterisation, model extractions, PDK construction and support for circuit designers and process engineers.
• Investigations of robust circuit operation under large load mismatch for ESA.  Circuit based techniques were explored to remove the requirement for an isolator component for S- and L- band circuits.  Novel temperature and peak field sensing strategies were theoretically demonstrated and await test circuit assembly.  
• Investigation of robust circuit operation in the presence of input overdrive conditions. GaN technology offers the opportunity to delete the limiter function in a receiver line-up.  GaN device and MMICs were designed to evaluate simultaneous low noise and high field withstand.
• MMIC designs using proprietary GaN process.  Various MMIC designs were performed including power amplifiers and LNAs
• Wide bandwidth power amplifier designs using the Triquint process.
• Realisation of S band >50W class AB hybrid amplifiers using GaN devices.  Early demonstration of modules with device power densities several factors higher than GaAs using a European device technology.
• Design of circuits for transmit/receive modules using ball grid array technology at 10 GHz.
• Design of a 90 GHz LNA MMIC, on the Ommic GaAs mHEMT process.
• Mixed signal circuit designs using GCS InP HBT technology including gain blocks, prescalars and VCO/prescalar MMICs.