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SUMMARY:From Devices to Systems : New MEMS for Next Generation RF Platform
 s
DTSTART:20161011T150000
DTSTAMP:20260929T053351Z
UID:2d249d89bba967688002d8127369cd85d7122a4804959c10cacde7f1
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Cristian Cassella\, Northeastern University\, Boston\nThe 
 growing need of miniaturized and fully integrated microwave circuits is pu
 shing designers to consider the use of microelectromechanical (MEMS) devic
 es\, such as resonators and filters\, instead of Quartz and Surface Acoust
 ic Wave (SAW) off-chip components. \n\n \n\nAluminum Nitride piezoelectr
 ic MEMS acoustic devices are particularly appealing as they can be fabrica
 ted through CMOS compatible fabrication processes\, hence enabling the int
 egration\, on the same chip\, of both electrical components and frequency 
 selective elements. This feature renders their role crucial for the develo
 pment of next-generation integrated wireless platforms. In this talk\, the
  operation and performance of previously demonstrated Aluminum Nitride (Al
 N) film-bulk-acoustic resonators (FBARs) and contour-mode resonators (CMRs
 ) are discussed. In addition\, the operation of two new-classes of AlN pie
 zoelectric resonators\, labeled as “Cross-Sectional Lame’ Mode resonat
 ors (CLMRs)” and “Two-Dimensional Mode resonators (2DMRs)”\, is desc
 ribed. Both technologies rely on the combined use of multiple piezoelectri
 c coefficients of AlN to enable the excitation of two-dimensional modes of
  vibration in AlN plates.\n\nThe adoption of CLMRs has allowed to achieve 
 record-high kt2 (6.2%) and a Figure of Merit (FoM=Q) in excess of 108 in A
 lN resonators operating around 920 MHz. Also\, as the resonance frequency 
 of CLMRs can be defined lithographically\, the first two contiguous wideba
 nd ladder-filters\, exclusively based on lithographically defined CLMRs\, 
 were demonstrated. Such devices show a fractional bandwidth in excess of 3
 .3% and an insertion-loss (I.L.) lower than 0.4 dB\, hence experimentally 
 demonstrating the exciting capability of CLMRs to achieve similar performa
 nce of commercial FBAR-based filters\, but through significantly reduced f
 abrication complexity and costs. Moreover\, two novel RF systems based on 
 the use of MEM devices and exploiting unique functionalities are showcased
 . One consists in the first fully-passive MEM-based sensor for near-zero p
 ower detection in radios. Such sensor behaves as a trigger capable of acti
 vating the CMOS-circuitry through extremely low-power (<-60 dBm) wake-up s
 ignatures.\n\nThe achievement of such a low-power RF-sensor is a key advan
 ce towards the commercialization of energy-efficient wireless platforms\, 
 with supreme battery-time\, to be used for the internet of things (IoT). T
 he other system that will be discussed consists in the first MEM-based RF 
 circulator for multiband SPAR platforms\, thus relying on the same carrier
  frequency for both transmitter and receiver modules. Such system relies o
 n the recently developed angular momentum biasing technique to achieve mag
 neto-free non-reciprocity. The system can tolerate high power levels in ex
 cess of 35 dBm through the adoption of body-anchored AlN-CLMRs (i.e. a var
 iant of AlN CLMRs using engineered supports to enable mitigation of therma
 l nonlinearities). The simulated performance of MIRC show fractional bandw
 idths in excess of 5%\, low insertion-loss and high skirt-steepness throug
 h a CMOS-compatible fabrication process.\n\n \n\nBio : Cristian Cassella 
 is currently an Associate Research Scientist in the Electrical and Compute
 r Engineering department at Northeastern University\, Boston.\n\nHe receiv
 ed his B.S.E in 2006 at University of Rome – Tor Vergata. In 2009 he rec
 eived his M.Sc at University of Rome – Tor Vergata. In 2011\, after two 
 years spent in the aerospace industry\, he was a visiting scholar at Unive
 rsity of Pennsylvania\, Philadelphia\, USA.  In 2012 he entered in a Ph.D
  program at Carnegie Mellon University which he completed in 2015.\n\nIn 2
 015 he was a postdoctoral research associate at Northeastern University\, 
 Boston. In 2016 he became Associate Research Scientist at Northeastern Uni
 versity. His research focuses on piezoelectric micro and nano electromecha
 nical systems (M/NEMS) for RF wireless communication platforms. His areas 
 of interests include characterization and design of MEMS resonators and de
 sign of linear and nonlinear RF circuits. He is author of more than 30 pub
 lications in peer-reviewed journals and conference proceedings and holds o
 ne patent and 4 patent applications in the area of MEMS resonators and sys
 tems. One of his conference papers on phase-noise reduction was selected a
 s Best Paper Award at the 2013 IEEE International Frequency Control Sympos
 ium (Prague). One of his journal papers was identified as a paper of excel
 lent quality\, hence being highlighted as a JMEMS RightNow-Paper to a larg
 e community of readers and being released as open access for a limited tim
 e. He is a technical reviewer for several journals\, such as Applied Physi
 cs Letter\, IEEE Journal of MicroElectroMechanical devices and Electron De
 vice Letter. 
LOCATION:BM 1130 https://plan.epfl.ch/?room==BM%201130
STATUS:CONFIRMED
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