Candidate
Ali Mojdeh
Title
Aluminum Nitride SAW Resonators
Supervisor
Raafat Mansour
Abstract
There are many devices that need filters for capturing signals and conditioning them in wireless systems and communication. Microwave filters for long were the center of attention for these types of signal conditionings. However acoustic filters have been given great attention recently for their miniature size and high quality factor.
Among many different acoustic filters SAW filters which only metal layers on top of the piezoelectric substrate have studied in this work. In this thesis the piezoelectric material used is aluminum nitride which exhibits to have higher quality factor in SAW resonators in comparison to lithium niobate or other piezoelectric materials.
In this study an extensive analysis of SAW structures are carried out. The relationship between physical dimensions, piezoelectric properties and filter specifications is investigated. The design procedure was followed by and verified by the simulation tools such as COMSOL and Coventorware. For resonators and filters several prototype units are fabricated through CMC/MEMSCAP.
The tests were done in the Center for Integrated RF Engineering (CIRFE) lab in University of Waterloo. As expected the Q factor of the designed resonator is proven to be higher than lithium niobate. The designed and tested resonator are used to create an acoustic 3 pole filter which is further simulated to be tunable using variable inductors and capacitors.