Antenna Research
The basic role of an antenna is to act as a transducer between an RF transceiver and an air medium. Its advanced role is to produce an EM wave with suitable pattern and polarisation, that will enhance signal reception from desired directions and suppress an interference from undefined sources. In recent years the role of antennas has undergone considerable changes driven by:
- a rapid expansion of wireless systems
- demand for advanced capabilities and high speed responses
- existence of new manufacturing technologies and design tools.
Current projects include:
- switched beam and phased array antennas for mobile satellite communications
- flat and multiple element antennas for wireless communications
- active planar antennas for power combining
- wideband smart antennas and MIMO systems
The outdoor field trial of the 8-element switched beam array antenna designed and developed by UQ for Mobilesat.
Photonics
VCSEL-based self-mixing sensors
The self-mixing phenomenon occurs when the laser beam is
partially reflected from an external target and injected back into
the laser cavity. The reflected light interferes or ‘mixes’ with the
light inside the laser cavity and produces variations to the
threshold gain, emitted power, lasing spectrum and the laser
junction voltage. The resulting output power variations are usually
monitored by using the photodiode integrated within the laser
package. This phenomenon allows the laser to be used as an
interferometric sensor incorporating the light source and the
interferometer in one device thus significantly reducing the cost
and the complexity of the sensing system.
The purpose of this project is to provide a practical and
theoretical knowledge base for the design and application of a
completely novel family of biomedical imaging sensors based on
two-dimensional arrays of Vertical-Cavity Surface-Emitting Lasers
(VCSELS).
Representative publications:
J. R. Tucker, Y.-L. Lim, A. V. Zvyagin and A. D. Rakić, “A massively Parallel Imaging System Based on the Self-Mixing Effect in a Vertical-Cavity Surface-Emitting Laser Array,” Appl. Opt. 46 (25), 6237-6246 (2007)
J. R. Tucker, A. D. Rakić, C. J. O’Brien, A. V. Zvyagin “The effect of multiple transverse modes in self-mixing sensors based on Vertical-Cavity Surface-Emitting Lasers,” Appl. Opt. 46 (4), 611-619 (2007)
For more information please please contact Dr Rakic - email.
Design and Modelling of Organic Microcavity Light Emitting Diodes
We are working on modelling, design, and optimisation of novel organic light emitting structures.
Project is being conducted in collaboration with Prof Djurisic's group at The University of Hong-Kong, Hong-Kong, and draws on our earlier successful work on compound semiconductor materials for surface-normal light emitters.
Representative publications:
C. H. Cheung, A. B.
Djurišić, C. Y. Kwong, J. Chan, A. D. Rakić, H. L. Tam, K. W.
Cheah, Z. T. Liu, W. K. Chan, and P. C. Chui, “Dependence of the
emission from tris(8-hydroxyquinoline) aluminum based microcavity on
device thickness and the emission layer position,” Thin Solid
Films 489 (1-3), 235-244 (2005)
C. H. Cheung, A. B. Djurišić, C. Y. Kwong, H. L. Tam, K. W. Cheah,
Z. T. Liu, W. K. Chan, P. C. Chui, J. Chan and A. D. Rakić,
“Reduced angular dependence of the emission from
Tris(8-hydroxyquinoline) aluminum based microcavity,” Opt. Commun.
248 (1-3), 287-293 (2005)
For more information please please contact Dr Rakic - email.
