- Electrical Engineering and Computer Science
Top 3 Areas of Expertise:
I like challenges and tackling tough problems. My research has always been a pioneering work. Being autonomous and self-motivated was essential for my success.
My execution philosophy is to do things right: solve problems once and forall. It heavily relies on automation (I code everything) and centeralization. I like to setup my work to be able to accomodate specification changes on all levels.
Expected date of graduation:
Frequency sources and high quality filters based on mechanical resonators are essential building blocks for both analog and digital electronics, and communication systems. Integration with standard integrated circuit (IC) technology has always been the goal of resonators technology, for reduction in power consumption, size, weight and overall fabrication cost. Micro-Electro-Mechanical (MEM) resonators offer an ultimate solution when compared to on-chip LC tank circuits. They are capable of achieving 100× higher quality factors, 104× smaller area and also has the potential for monolithic integration with standard IC technology. The first part of this thesis is dedicated to a new class of monolithically integrated CMOS-MEMS resonators at GHz- frequencies, that are truly solid-state, without any exposed moving surfaces and don’t require any kind of post-processing or special packaging. Acoustic vibrations are confined in the front-end-of-line (FEOL) layers of the CMOS process by means of a phononic crystal (PnC) constructed in the back-end-of-line (BEOL) layers of the process. Electrostatic actuation is used, whereas piezoresistive filed-effect-transistor (FET) sensing is used with emphasis on its advantage over other transduction techniques. Simulation, modeling, optimization, prototyping and testing of these resonators is presented, with the performance enhancement with each new device generation is highlighted. The thesis also explores the integration of Lamb-mode resonators in standard GaN monolithic-microwave-IC (MMIC) process. The first monolithic 1GHz MEMS- based oscillator in GaN MMIC technology is demonstrated. Monolithic lattice and ladder filters are also demonstrated in standard GaN MMIC technology.
5 Recent Papers:
B. Bahr, R. Marathe, and D. Weinstein, “Theory and design of phononic crystals for unreleased CMOS- MEMS resonant body transistors,” Microelectromechanical Systems, Journal of, vol. PP, no. 99, 2015.
B. Bahr, L. Popa, and D. Weinstein, “1GHz GaN-MMIC monolithically integrated MEMS-based oscil- lators,” in Solid- State Circuits Conference - (ISSCC), 2015 IEEE International, Feb 2015, pp. 1–3.
B. Bahr, R. Marathe, and D. Weinstein, “Phononic crystals for acoustic confinement in CMOS-MEMS resonators,” in Frequency Control Symposium (FCS), 2014 IEEE International, May 2014, p. pp.
B. W. Bahr, D. Weinstein, and L. Daniel, “Released resonant body transistor (RBT) model,” Oct 2014. [Online]. Available: https://nanohub.org/publications/17
P. Maffezzoni, B. Bahr, Z. Zhang, and L. Daniel, “Analysis and design of weakly coupled LC oscillator arrays based on phase-domain macromodels,” IEEE TCAD, vol. 34, no. 1, pp. 77–85, Jan 2015.