Technical Lectures

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Asad Abidi
Univ. of California, Los Angeles
601-603
Abstract

Even circuit designers who are experienced with low noise design can find it difficult to explain how noise is quantified and analyzed.

I will explain the formal methods of quantifying noise and illustrate their use in the design of a variety of common RF circuits. For linear time-invariant circuits such as small-signal amplifiers, noise transfer functions play a key role. For time-varying circuits such as passive mixers and LC oscillators, noise is in many cases injected in discrete time. Methods for the design continue to evolve towards greater simplicity, and I will present some of them.

There is seldom a noise optimum in these circuits. It is usually a tradeoff, as I will show, between noise, large-signal linearity, and power dissipation.

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Abbas Omar
Univ. of Magdeburg
501-502
Abstract

Millimeter Wave mobile communication (5G and beyond) has been associated with much lower radiation power and much shorter communication range. Millimeter Wavelengths suffer from very strong attenuation in water-rich substances limiting penetration into biological objects (e.g., human and animal bodies and plants) to just a few millimeters. Deeper inside the body the intensity is negligible making for greater safety compared to early mobile standards (3G and 4G). However, the safety of millimeter-wave radiation for 5G and beyond remains a public concern. 
This Technical Lecture aims to comprehensively review the relevant electromagnetic fundamentals underlying the wave-matter interaction involved in any eventual health hazard which might be associated with millimeter-wave radiation. Basic related aspects include the following: 
•Direct health hazards must involve either chemical reactions or thermal/mechanical destruction of cells/tissues. This must be accompanied by energy transfer from the electromagnetic wave to the biological substances.
•Indirect hazards include overloading the biological mechanisms involved in the body thermoregulation. 
•Thermal effects involve rise of temperature, an increase in the magnitude of atomic/molecular lattice vibrations.Chemical reactions (e.g., burning) will only occur if the temperature increase exceeds a certain limit. Otherwise, the rise is reversible, regulated to steady state by the blood circulation within the body. 
•Non-ionizing waves are wavelengths that are much larger than the atomic/molecular scale, a continuous spatial distribution of the wave is an adequate mathematical representation. The wave power-density is described by the Poynting vector, and the power transfer from the wave to the biological substances can be calculated with high precision using the concept of constitutive parameters (conductivity, permittivity, and permeability). Millimeter Waves and even Tera-Hertz Waves belong to this category. 
•Ionizing radiation has wavelengths comparable to the interatomic or intermolecular spaces and an electromagnetic wave quantization approach makes sense. Wave-matter interactions can be explained using the discrete representation of the waves, photons, which are ensembles of energy packages highly localized in time and space. A single photon carries energy proportional to its frequency which, e.g., can be fully transferred to and result in electrical destruction of a molecular bond. Ionizing radiation only occurs at frequencies much higher than that of ultraviolet light and therefore is not applicable to the millimeter-wave case. 
•Use of a photon representation to describe Millimeter Waves would require the photon spatial extent to be of the same order of magnitude as the wavelength and a photon collision would necessarily involve millions of atoms/ molecules (as if swimming in it). A single chemical bond could not absorb the entire photon energy  




Speaker Bio: Abbas Omar received the B.Sc., M.Sc. and Doktor-Ing. degrees in electrical engineering in 1978, 1982 and 1986, respectively. He has been professor of electrical engineering since 1990 and director of the Chair of Microwave and Communication Engineering at the University of Magdeburg, Germany from 1998 to his retirement in 2020. He joined the Petroleum Institute in Abu Dhabias a Distinguished Professor in 2012 and 2013 as an organizer of the research activities for the Oil and Gas Industry in this area. In 2014 and 2015 he chaired the Electrical and Computer Engineering at the University of Akron, Ohio, USA. Dr. Omar authored and co-authored more than 480 technical papers extending over a wide spectrum of research areas. His current research fields cover the areas of microwave, magnetic-resonance, and acoustic imaging, microwave and millimeter-wave material characterization, phased arrays and beamforming, massive MIMO, indoor positioning, subsurface tomography and ground penetrating radar, and field theoretical modeling of microwave systems and components. He is IEEE Fellow

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Robert Caverly
Villanova Univ.
4A-4C
Abstract

The microwave and RF design engineer always seeks to develop a design that will meet specifications the first time that the circuit is fabricated. To do so requires that as many elements and phenomenon as possible associated with the control devices and circuit be accurately modeled. In the case of the microwave and RF semiconductor control circuits, accurate modeling of the solid-state control components over frequency, voltage, current and power is key to successful control system design. This talk will cover material that will provide the RF and microwave design engineer insight into the physical operation and modeling of PIN diodes and field-effect transistors (FETs) as control components and their use in microwave and RF control circuits. The talk will cover basic RF and microwave control circuits for reconfigurable electronics, and then focus on linear and nonlinear models for PIN diode, MESFET and MOSFET control elements to implement these circuits. The talk will conclude with control circuit examples using these models for use in reconfigurable RF and microwave electronics.




Speaker Bio: Dr. Robert H. Caverly received his Ph.D. degree in electrical engineering from The Johns Hopkins University, Baltimore, MD, in 1983. He has been a faculty member at Villanova University in the Department of Electrical and Computer Engineering since 1997 and is a Full Professor. Previously, he was a Professor for more than 14 years at the University of Massachusetts Dartmouth. Dr. Caverly's research interests are focused on the characterization of semiconductor devices such as PIN diodes and FETs in the microwave and RF control environment. He has published more than 100 journal and conference papers and is the author of the books Microwave and RF Semiconductor Control Device Modeling and CMOS RFIC Design Principles, both from Artech House. An IEEE Life Fellow, Dr. Caverly is currently the Editor in Chief of the IEEE Microwave Magazine and a Track Editor for the IEEE Journal of Microwaves. He is currently an elected member of the MTT-S Administrative Committee as well as a the HF-VHF-UHF Technology and Biomedical Applications Technical Committees of the MTT Society.