“Advance Microwave and RF Design for MMIC” by Professor Grant A. Ellis, Department of Electrical and Electronic Engineering, Universiti Teknologi Petronas, Malaysia.

Date:  March 9, 2011 (Wednesday)
Time:  7:30pm – 9:00pm; 6:30pm networking
Venue:  PSDC, Room 1202, 1 Jalan Sultan Azlan Shah, 11900 Bayan Lepas, Penang, Malaysia

Admission is free.  Refreshments will be served before the lecture.  Network and interact with like-minded engineers and researchers before the seminar begins.

Abstract

In this presentation, projects in the area of microwave circuit design and computer aided design at UTP will be discussed.  A tuneable matching network integrated into the interstage of a two-stage MMIC amplifier to provide the capability for center frequency tuning is described.  The M-probe method is used to analyze the mismatch loss in the interstage to compensate for roll-off and equalize the gain between tuning states. The reconfigurable amplifier offers the advantage of center frequency tuning from 1.37 GHz to 1.95 GHz in four switched bands which covers standards for analog and digital cellular telephony.  Broad band high linearity is a requirement in future RF systems.  In another project, adding low impedance terminations at the envelope frequency (>ω2–ω1) to the input of a Gallium Arsenide Heterojunction Bipolar Transistor Distributed Amplifier is shown to improve the third order output intercept point (OIP3) over a bandwidth of 0.5 GHz to 3 GHz by up to 7.4 dB.  Furthermore, OIP3 can be increased up to 19.2 dB above P1dB. Results show that the improvement in OIP3 comes without lowering gain, return loss or P1dB and that the optimum termination is nearly a short circuit at the envelope frequency.  A physics-based model using Wheelers Incremental Inductance rule for calculating the change in inductance due to variations in the physical parameters of planar spiral inductors is given.  It is shown that the series resistance of an MMIC inductor is a useful figure of merit for the robustness of the inductor against etching variations during fabrication.  Circular inductors are shown to have less inductance variation than rectangular inductors.  Our model can be evaluated quickly using a circuit simulator without the need for expensive EM analysis. A procedure based on the Richardson extrapolation method is used to extract the resistance values without long computation time.  Finally, some new directions for research will be discussed.

Speaker

Grant A. Ellis received his Ph.D. degree in electrical engineering from the University of Washington, Seattle, in 1995.  He is currently Professor of Electrical and Electronic Engineering at the Universiti Teknologi Petronas in Tronoh, Malaysia.  His current research interests are Monolithic Microwave Integrated Circuit (MMIC) and RFIC design, novel millimeter wave MMIC design, Microwave computer aided design techniques, and electromagnetic propagation.  Dr Ellis has written over 30 papers and publications and holds 4 US patents.  He is a member of the Tau Beta Pi and Eta Kappa Nu National Engineering Honor Societies and the Sigma Xi scientific research society.  He is a registered professional engineer in the State of California, and has been a Senior Member of the IEEE since 2004.