Speaker: Dr. Ehsan Afshari
Assistant Professor
Faculty in Electrical and Computer Engineering
Cornell University

Title: Signal Generation and Processing Beyond Transistor Limits

(1)
Local Host: Dr Mahdi Shabany

Time: Monday, December 28th, 10:00am
Kharazmi Hall, Department of Computer Engineering
Sharif University of Technology, Tehran

(2)
Local Host: Dr. Ramtin Khosravi

Time: Tuesday, December 29th, 1:00pm
Amphitheater, Faculty of Electrical and Computer Engineering
University of Tehran, Tehran

Abstract:
Waves are everywhere, from the distribution of cars on a highway to the wave patterns in the
ocean. Intriguing phenomena in wave propagation can be used in many practical applications leading to novel architectures for signal processing and generation. More specifically to overcome the limitations of active devices in high frequency signal generation and processing, we propose a general class of solutions based on novel circuit topologies inspired by commonly used structures in electromagnetics, and more specifically optics. The principles behind these designs stem from the mathematical theory of linear and nonlinear wave propagation. By analyzing the models for the transmission lines/lattices, we are able to exploit the large body of theory to design circuits, demonstrating the narrowest reported pulse on silicon(1.5ps with a 3V amplitude). Next, we will show how to generate a 300GHz signal in a 130nm CMOS
process using the Doppler shift. This circuit generates 10,000 times more power than the best published work in the same process. We will also show how to use the same principle to generate multi-Watt-level power at more than 100GHz on a GaN process. Finally we will present how the same approach can be applied to realize circuits and systems with a negative noise figure for one component of the signal and very low phase noise oscillators in CMOS.