EECS500 Spring 2018 Department Colloquium

Cristian Cassella
New MEMS Technologies for Next Generation RF Platforms: from Devices to Systems
Northeastern University
White 411
11:30 AM - 12:30 PM
February 22, 2018

In the last two decades, microelectromechanical systems (MEMS) have enabled unique functionalities in commercial Radio-Frequency (RF) systems, such as large spectral efficiency, small form factors and large data rates. As 5G is now approaching, their use in millimeter-wave front-ends opens to a deeper level of interaction between mechanical and electromagnetic domains, leading to more efficient and secure communication architectures. In this talk, new RF components based on Aluminum Nitride (AlN) MEMS resonant systems are showcased. First, two new classes of AlN piezoelectric resonators, labeled as “Cross-Sectional Lamé Mode Resonators (CLMRs)” and “Two-Dimensional Mode Resonators (2DMRs)”, are described. It is shown how these devices can be used to lithographically define monolithically integrated RF-wideband filtering banks, through the multi-modal excitation of high-frequency acoustic waves in AlN plates. Then, the operation and performance of the first MEMS-based zero-power wake-up receiver are described. This device uses the high quality factor of a MEMS device to achieve extremely low power sensitivity (-60 dBm at 750 MHz) without consuming power. Finally, we show a new approach to enable the use of high-frequency MEMS-based local oscillators for frequency conversion stages in telecommunication datalinks. This approach, based on the nonlinear dynamics of parametric amplifiers, allows us to achieve superior phase-noise cancellation through on-chip solid-state components. These demonstrations point to a key role for MEMS components in future wireless communication systems.


Cristian Cassella is currently an Associate Research Scientist in the Electrical and Computer Engineering department at Northeastern University, Boston, MA.  He received his B.S.E. and M.Sc., with honors, at University of Rome – Tor Vergata in 2006 and 2009, respectively. In 2011, he was a visiting scholar at University of Pennsylvania. In 2012 he entered a Ph.D. program at Carnegie Mellon University which he completed in 2015. In 2015 he was a Postdoctoral Research Associate at Northeastern University. In 2016, he became Associate Research Scientist. He is author of more than 40 publications in peer-reviewed journals and conference proceedings. Two of his peer-reviewed journal papers published on the IEEE Journal of Microelectromechanical Systems (JMEMS) were selected as papers of excellent quality (JMEMS RightNow Papers), hence being released as open access. One of his journal papers was chosen as the cover for the Nature Nanotechnology October 2017 issue. He won the Best Paper Award at the IEEE International Frequency Control Symposium (2013, Prague). In 2018, he was awarded the prestigious Marie-Sklodowska-Curie Individual Fellowship.  He holds two patents and 3 patent applications in the area of MEMS resonators and RF systems. He is a technical reviewer for several journals, such as Applied Physics Letters, IEEE Journal of Microelectromechanical Systems, IEEE Electron Device Letters, Journal of Micromachine and Microengineering, Journal of Applied Physics, IEEE Sensors Letters, IEEE Transaction on Electron Devices and Review of Scientific Instruments.