Research

Featured Researcher: Bozidar Marinkovic

The focus of Bozidar’s research within Koser Lab is to develop a power harvesting device for a low power wireless sensor node. Currently, the sensor nodes are powered using batteries that are bulky and require multiple replacements. Our device, named Smart Sand, provides an attractive alternative to battery-operated systems, especially for long-term and low-power applications by harvesting the energy from environmental vibrations. Unlike conventional vibration-to-electric conversion systems, these piezoelectric-based microscale devices are designed to operate across wide bandwidths of low frequencies making them actually practical in real world environments [1].

Design specifications for Smart Sand and its packaging require a Cleanroom facility with tools capable of producing sub-micron precision. The whole fabrication process is made up of 9 photolithography steps on multiple silicon substrates. In order to make a functional device it is absolutely critical that the alignment and accuracy of each photolithography mask is made within fractions of a micron. Having the tools such as Heidelberg (mask making tool) and EVG (mask aligning tool) makes this research possible here at Yale University. Our photolithography masks can be designed and fabricated without worrying about long turnaround times or conversion errors introduced by other third party vendors. Continuous access to these tools and experienced staff that is always willing to help creates a productive environment and allows us to experiment and bring to reality the complex geometries of Smart Sand.

[1] B. Marinkovic and H. Koser, Appl. Phys. Lett. 94, 103505 (2009)

 

Bozidar Marinkovic got his Bachelor of Science degree in Electrical Engineering from Trinity College, Hartford, CT in May 2005. In his undergraduate studies he worked on variety of projects including the design of autonomous ground vehicles with Prof. David J. Ahlgren and digital signal processing with Prof. Taikang Ning. In his senior year he was selected as a member of Phi Beta Kappa academic honor society. After graduating as a valedictorian from Trinity College, Bozidar started the Ph.D. program at Electrical Engineering Department at Yale University where he got his Masters of Science in December 2006. Currently Bozidar is working in Prof. Koser's MEMS Design and Characterization Group.

 

 

 

 

 

 

Unpackaged Smart Sand. The device contains a large proofmass and four active piezoelectric tethers that can convert vibrations to electricity

Scanning Electron Microscope (SEM) image showing how first five layers are stacked and aligned during Smart Sand fabrication

Scanning Electron Microscope (SEM) image of piezoelectric cross section showing how Lead Zirconium Titanate thin film is sandwiched between two metal electrodes on top of silicon substrate

 

 

 

 

 

 

Yale School of Engineering & Applied Science