Exploration of lead-free composition materials for tunable filter applications
 George Li
Mentor: Professor Amar Bhalla
 
               The ferroelectric and piezoelectric properties of tunable materials BST (Barium Strontium Titanate) and BZT (Barium Zirconium 
Titanate) are of high interest because of their potential application in novel communications technologies.  The changes in the materials’ dielectric 
constant and loss, remnant polarization, and hysteresis 
loops will be studied, by varying the applied electric field and temperature (13K to 293K).  The aim of the research is to establish a high figure of 
merit, lead free perovskite compound.  (Lead free perovskite compounds are in high demand due to the negative impact of lead on the 
environment.)
 
               We seek to develop and improve the usefulness of (BaSr)TiO3-BST and Ba(ZrTi)O3-BZT for use in components and subsystems for 
communications and other related applications that utilize the field variable properties of paraelectrics, ferrites, or other materials.  These 
materials can potentially play a central role in the development of tunable RF filters, which allow the ability to tune the bandwidth and frequency 
of RF filters and antennas.  Continuously variable phase shifting for use in RF receivers and antennas is another example of the many applications 
made possible by these special materials.