Dr. Tharaka Dissanayake, PhD, BSc. Eng
MIET, MIEEE

Associate Lecturer,
School of Electrical Engineering and Computer Science,
University of Newcastle, University Drive, Callaghan, NSW2308
Australia

Current Research

My current research in wireless systems is 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.