Real-time 3-d localization using radar and passive surface acoustic wave transponders

Abstract

This thesis covers ongoing work into the design, fabrication, implementation, and characterization of novel passive transponders that allow range measurements at short range and at high update rates. Multiple RADAR measurement stations use phase-encoded chirps to selectively track individual transponders by triangulation of range and/or angle measurements. Nanofabrication processes are utilized to fabricate the passive surface acoustic wave transponders used in this thesis. These transponders have advantages over existing solutions with their small size (mm x mm), zero-power, high-accuracy, and kilohertz update rates. Commercial applications such as human machine interfaces, virtual training environments, security, inventory control, computer gaming, and biomedical research exist. A brief review of existing tracking technologies including a discussion of how their shortcomings are overcome by this system is included. Surface acoustic wave (SAW) device design and modeling is covered with particular attention paid to implementation of passive transponders. A method under development to fabricate SAW devices with features as small as 300nm is then covered in detail. The electronic design of the radar chirp transmitter and receiver are covered along with the design and implementation of the test electronics. Results from experiments conducted to characterize device performance are given.