Past
Research
My research in wireless
systems has been focused on Ultra-wideband
(UWB) antennas. UWB antennas need to operate
over a large bandwidth and they are integral
parts of a pulse radiating system. The
initial challenge addressed in my research
was designing low-cost and small antennas.
The low-cost and ability to integrate
easily with portable devices are very
important requirements of UWB antennas
in wireless devices. The two novel antennas,
the triangular-shaped printed planar monopole
[7] and the L-shaped wide-slot antenna
[8], were designed to fullfill these requirements.
It is the simplicity of these designs
make them attractive to be used in wireless
mobile systems. It is always appealing
to obtain closed-form and fast solutions
to electromagnetic problems. Finding a
new application for existing theoretical
concepts is something that I enjoy; the
proposed new analytical method in frequency-notched
antenna design [1] is a good example.
I used experimental equations, developed
elsewhere to calculate guided wavelength
of slot-lines, to successfully predict
the notch frequency of the slot integrated
UWB printed antennas. This new method
very accurately predicts notch frequency,
faster than full-wave simulations. Another
important contribution of my PhD research
is emphasizing the relationship between
the pattern stabil- ity and the impulse/frequency
response of the UWB antennas [5]. I showed
how the direction dependent distortion,
imposed on the radiated pulse by the antenna,
affects the overall UWB system optimization
[6, 2]. The method proposed in [4] is
a novel approach to achieve best possible
multi-directional UWB system optimization,
especially when the antenna has a direction
dependant frequency response. This also
lead to a new figure of merit called Pattern
Stability Factor (PSF), used for comparing
antenna radiation performance. This is
one of the first para- meters of its kind,
which is capable of expressing the stability
of both phase and magnitude of antenna
radiation patterns. I used PSF in analyzing
and comparing small, low-cost and low-dispersion
UWB antennas [3].
Research Plan
With an academic/research
position, I expect to perform as a part
of a group, which has expertise not only
in EM techniques, but also in modulation,
coding and signal processing. I will be
responsible of investigating how antenna
and sensor parameters affect the overall
system performance. In-house measurement
facilities will be developed as master
and honors level projects. Experimental
prototypes will be built to test the implementation
of the concepts. I will actively pursue
funding for infrastructure development
for EM research from internal and external
institutions. I will also encourage publishing
in journals and conferences to receive
feedback, and to demonstrate research
progress.
References
[1] T. Dissanayake
and K. P. Esselle, "Prediction of
the Notch Frequency of Slot Loaded Printed
UWB Antennas,"accepted to be published
in IEEE Transactions on Antennas and Propagation.
[2] A Method to Include Antenna Pattern
Characteristics in UWB System Design,"
in Proceedings IEEE International Conference
on Wireless and Ultrawideband Technology,
March 2006.
[3] Comparison of UWB Antennas Considering
Pattern Variation with Frequency,"
in Proceedings IEEE International Symposium
on Antenna and Propagation, July 2006,
pp. 4665{4668.
[4] Correlation Based Pattern Stability
Analysis and a Figure of Merit for UWB
Antennas," IEEE Trans-actions on
Antennas and Propagation, vol. 52, no.
11, pp. 3184{3191, November 2006.
[5] Pulse Correlation and UWB Antenna
Pattern Stability," in Proceedings
12th International Symposium on Antenna
Technology and Applied Electromagnetics,
Antem/URSI 2006, 2006.
[6] Waveform Optimization of UWB Radio
Systems Over a Range of Directions,"
Electronics Letters, vol. 42, no. 7, pp.
384{385, March 2006.
[7] T. Dissanayake, K. P. Esselle, and
Y. Ge, \A Printed Triangular-Ring Antenna
with a 2:1 Bandwidth," Mi-crowave
and Optical Technology Letters, vol. 44,
no. 1, pp. 51{53, January 2005.
[8] Integrated Compact Ultra-wideband
L-shaped Wide Slot Antennas," in
Proceedings Asia-Pacific Mirocrowave Conference,
vol. 1, December 2005. |
