Distinguished Lecturers’ Talks
Presentations by IEEE Distinguished Lecturers
on Monday morning, January 20, 2014
Embrace Circuit Nonlinearity to Get Transmitter Linearity and Energy Efficiency
Dr. Earl McCune, Besser Associates
Wireless communications signals have evolved greatly over the past century, from the use of Morse Code to very complicated digital modulation schemes such as wideband CDMA (WCDMA) and 3GPP Long-term evolution (LTE). This progression challenges the design of transmitters to be simultaneously energy efficient, low distortion, and spectrally clean. The increasing peak-to-average power ratio (PAPR) characteristic of these signals is a particular problem. Because it is important to understand why this is happening this presentation begins with a discussion of the physical implications of Shannon’s Capacity Limit combined with the Fourier Transform.
A ‘backwards’ design perspective is then presented, where we begin design from a maximally energy efficient circuit (a switch) and then make it generate the required signals instead of the conventional approach of beginning with linear circuitry and then finding ways to improve its energy efficiency. This directly leads to the design and implementation of polar-modulation to improve both the energy efficiency of the power amplifier and linearity of the transmitter. Design of intentionally compressed circuitry is very different from conventional linear amplifier techniques, and these new design techniques will be discussed.
The presentation will cover the use of both linear amplifiers and switches for the power amplifier module, and the implications of using these approaches on the power supply design, system integration, and performance measures. This presentation will bring the subjects of OFDM, Shannon’s theorem, spectral efficiency, and switch-mode amplifiers together in an exposition of polar modulation transmitters that is both entertaining and informative.
Earl McCune received his BS/EECS degree from UC Berkeley, his MSEE (Radioscience) from Stanford University, and his Ph.D. from UC Davis in 1979, 1983, and 1998 respectively. He is a serial Silicon Valley entrepreneur, founding two successful start-up companies since 1986: Digital RF Solutions (1986-1991, merged with Proxim) and Tropian (1996 – 2006, acquired by Panasonic). He is now retired from his position as a Technology Fellow of Panasonic, and is an author, instructor, and independent consultant. He is currently an instructor for Besser Associates for both Practical Digital Wireless Signals and Frequency Synthesis Principles. He holds 58 issued US patents, and is the author of Practical Digital Wireless Signals (Cambridge 2010).
In his nearly 40 years of experience in the wireless communications industry he has worked in areas including technology development, circuit design, along with systems architecture and integration. This experience has been gained at NASA, Hewlett Packard, Watkins-Johnson, Cushman Electronics, Digital RF Solutions, Proxim, Tropian, and Panasonic. The start-up Digital RF Solutions pioneered modulated direct digital synthesis (DDS) technology for very high dynamic range transmitters. Tropian developed and implemented envelope tracking and polar modulation techniques for highly efficient, multiband and multi-mode linearized power amplifiers.
Dr McCune has presented at ten (10) IMS/MTT workshops since 2000, and has been an invited speaker at RWS, PA Symposium, WAMICON, ISCAS, WCNC, and ISSCC. He has served on the CICC technical program committee (TPC) since 2000, and also served on the TPC for RWS and the PA Symposium. He is a regular reviewer for IEEE Journal of Solid State Circuits, Transactions on Microwave Theory and Techniques, and the Transactions on Circuits and Systems. He is a Senior Member of the IEEE, and is a member of the MTT, Communications, Solid State Circuits, Vehicular Technology, Aerospace Engineering, and Circuits and Systems Societies.
Dr. Luca Pierantoni, Polytechnic University of Marche, Italy
In view to the new epochal scenarios that nanotechnologics disclose, nanoelectronics has the potential to introduce a paradigm shift in electronic systems design similar to that of the transition from vacuum tubes to semiconductor devices. Since many nano-scale devices and materials exhibit their most interesting properties at radio-frequencies (RF), nanoelectronics provides an enormous and yet widely undiscovered opportunity for the microwave engineering community.
The lectures presents a technical overview of some of the main research fields of nanoelectronics for RF applications, i) showing the potentialities offered by emerging nano-scale materials (e.g. carbon nanotubes, graphene), ii) highlighting unprecedented microwave, millimeter-wave and THz devices and systems, iii) focusing on critical technologic aspects.
While the advancement of research in this area heavily depends on the progress of manufacturing technology, still, the global modeling of multi-physics phenomena at the nanoscale is crucial to its development. Modeling, in turn, provides the appropriate basis for design.
The aim of this effort is to close the gap between the nanosciences and a new generation of highly integrated and multifunctional devices, circuits, and systems, for a broad range of applications and operating frequencies, up to the optical region. This aim can be achieved by using the panoplia of microwave engineering at our disposal.
Luca Pierantoni was born in Maiolati Spontini, Italy. He received the ‘Laurea’ degree (summa cum laude) in Electronics Engineering in 1988 and the Ph.D. degree in 1993 in Electromagnetics from the Department of Electronics and Automatics at the University of Ancona, Italy.
From 1989 to 1995, he was with the same department, as a Research Fellow. From 1996 to 1999 he worked at the Technical University of Munich, Germany, in the Institute of High-Frequency Engineering as Senior Research Scientist. In 1999 he joined the Department of Electromagnetics at the Polytechnic University of Marche, Ancona, Italy as Assistant Professor. In 2002, he has been guest scientist at the Technical University of Munich. Presently, he is with the Department of Information Technology at the Polytechnic University of Marche.
His current research interests are in the investigation of the combined Maxwell-quantum transport problem in nanomaterials, the analysis of electrodynamics in nanostructures and in the development of computational techniques for the multi-physical modeling of micro- and nano-devices.
He is a member of the Italian University Network for the Physics of Matter (CNISM), the Italian Institute of Nuclear Physics (INFN), and he is the chair of the IEEE MTT-S “RF Nanotechnology” technical committee.
Remote Sensing of the Physical Qualities of Fruits
Dr. Monai Krairiksh, King Mongkut’s Institute of Technology, Thailand
Nondestructive determination of dielectric properties of materials is essential in various applications to monitor the nature of an object. Apart from many techniques like near infrared (NIR), X-ray, ultrasonic, and so on, a microwave based technique is of interest due to its low cost, high accuracy, and small size. In this talk the objective is to describe and present a novel way to determine in situ the ripening of fruits and how they can be applied in real time applications. This methodology has been applied to determine the quality of fruits like Durian, Banana, Mangosteen and the like.
A number of techniques exist for characterization of lossy dielectric objects at microwave frequencies. Many such techniques have been extensively developed, e.g. resonant and non-resonant methods. For the resonant method, the cavity perturbation technique is well suited for measuring low dielectric loss materials and the accuracy is limited only by the size of the cavity. For a non-resonant method, the transmission line technique needs an adequate thickness of the sample. An open-ended probe technique, which has been successfully commercialized, can measure over a wide frequency range with moderate accuracy, but the material sample must be sufficiently thick and the contact surface of the probe must be flat and free of air gaps.
In this methodology we propose to use a free space measurement technique used in RCS measurements and use the natural resonant frequency concepts to estimate the variation of the dielectric properties with time, and thereby relate to the physical characteristics of the fruit. What makes the problem challenging is that both the real and the imaginary parts of the dielectric constant for most frits is extremely high and even much greater than that of sea water! The variation of these electrical properties as a function of frequency will be described and how the singularity expansion method can be applied to estimate the variation of the natural resonant frequency of the various fruits as it ripens changing the sugar content with time will also be discussed.
In a free-space measurement technique, the amplitude and the phase of the returned probing signal are measured from a sample of interest which is placed between a transmitting and a receiving antenna. Thus, the measurement setup is quite complicated since one needs to measure both the magnitude and phase of the scattered signal. There have been attempts to simplify the measurement system. An interesting method is to omit the phase and measure only the reflection and the transmission coefficients instead. Subsequently, a coupled-dipole sensor using the magnitude of and has been developed.
This talk will provide an overview of the various measurement techniques and try to relate the electrical properties to the physical properties of the various fruits.
Monai Krairiksh was born in Bangkok, Thailand. He received the B.Eng., M.Eng. and D.Eng. degrees from King Mongkut’s Institute of Technology Ladkrabang (KMITL), Thailand in 1981, 1984, and 1994, respectively.
He was a visiting research scholar at Tokai University in 1988 and at Yokosuka Radio Communications Research Center, Communications Research Laboratory (CRL) in 2004. He joined the KMITL and is currently a Professor at the Department of Telecommunication Engineering. He has served as the Director of the Research Center for Communications and Information Technology during 1997-2002. His main research interests are in antennas for mobile communications and microwave in agricultural applications.
Dr.Krairiksh was the chairman of the IEEE MTT/AP/Ed joint chapter in 2005 and 2006. He served as the General Chairman of the 2007 Asia-Pacific Microwave Conference, and the advisory committee of the 2009 International Symposium on Antennas and Propagation. He was the President of the Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology Association (ECTI) in 2010 and 2011 and was an editor-in-chief of the ECTI Transactions on Electrical Engineering, Electronics, and Communications.
He was recognized as a Senior Research Scholar of the Thailand Research Fund in 2005 and 2008 and a Distinguished Research Scholar of the National Research Council of Thailand.