Design and analysis of direction-of-arrival estimation systems using electrically small antenna arrays

The rst direction-of-arrival systems were based on amplitude measurements of signals received from a single, nonstationary antenna. Next generation systems depended on phase measurements for direction-of-arrival information. With the advent of DSP-based direction fi nding, a return to amplitude-based measurements is possible. This enables direction-of-arrival estimation using arrays whose interelement phase di erence is very small or even negligible. Traditionally, direction- nding systems have been quite large to ensure a re- solvable phase delay between elements. Since the direction- nding arrays presented here are much less reliant on interelement phase delay, their footprints can be dramatically reduced. Electrically small antennas have the radiation pattern of an electric dipole, a magnetic dipole, or some superpo- sition of the two. Orthogonally oriented electrically small antennas receive with very distinct patterns when combined in an array, provided that the mutual coupling is small. With six elements measuring the Cartesian components of the electric and magnetic elds of an incident signal, it is possible to attain complete, unambiguous direction-of-arrival and polarization information with little to no phase di erence between the elements. Using small, co-located antenna arrays enables similar functionality to larger sensors while maintaining a much smaller footprint. Using electrically small antenna elements causes some limitations for these arrays when compared with the vector-sensor case. This dissertation explores the tradeo ffs in performance available for small direction- nding arrays in terms of physical array parameters such as element size, spacing, and feed parameters. Novel approaches are explored in measuring and feeding electrically small antennas, unmatched antennas, and antennas with low interelement spacing. With such a small array, a new generation of direction- nding devices is possible. These devices can serve a number of practical applications, including accurate portable handheld or vehicle-mounted direction-of-arrival estimation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Slater, Matthew

Contributors dc:contributor

• Bernhard, Jennifer T.
• Jones, Douglas L.
• Franke, Steven J.
• Schmitz, Christopher D.

• antennas
• direction finding
• direction-of-arrival estimation
• electrically small antennas
• amplified antennas
• vector sensors

Statement dc:rights

• Copyright 2012 Matthew Slater

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/34424

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/34424