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Majid M. Khodier talks with ScienceWatch.com and answers a few questions about this month's Fast Moving Front in the field of Computer Sciences. The author has also sent along images of their work.
Khodier Article: Linear array geometry synthesis with minimum sidelobe level and null control using particle swarm optimization
Authors: Khodier, MM;Christodoulou, CG
Journal: IEEE TRANS ANTENNAS PROPAGAT, 53 (8): 2674-2679 Part 2 AUG 2005
Jordan Univ Sci & Technol, Dept Elect Engn, Manassas, VA 22110 USA.
Jordan Univ Sci & Technol, Dept Elect Engn, Manassas, VA 22110 USA.
(addresses have been truncated)

  Featured Research Front Map on "OPTIMIZATION OF ANTENNA ARRAYS."


Why do you think your paper is highly cited?

My paper is highly cited because it was the first paper which applies the particle swarm optimization (PSO) method to find the spacings between the elements of a linear array, so that sidelobe level is reduced and nulls placed in any direction.

Does it describe a new discovery, methodology, or synthesis of knowledge?

 
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My paper describes the application of a newly invented, evolutionary optimization method, the PSO, to the geometry synthesis of a linear antenna array.

Would you summarize the significance of your paper in layman’s terms?

My paper serves as a benchmark for comparison with design procedures and results using other optimizations methods, such genetic algorithms (GA), simulate annealing (SA), etc. Since the time of its publication, my paper has been referred to many times by other researchers who use the PSO or other optimization methods to design antenna arrays. They compare their results with our paper’s results for validation.

How did you become involved in this research and were any particular problems encountered along the way?

In 2004, I visited the Uinversity of New Mexico in Albuquerque, to spend the summer working with Professor Christos Christodoulou on metamaterials. However, the research on metamaterials was going nowhere due to limited resources. Then, I came across the following paper: J. Robinson and Y. Rahmat-Samii, "Particle swarm optimization in electromagnetics," IEEE Trans. Antennas Propagat. 52 [2]: 397-407, February 2004. I quickly became interested in that paper, particularly in the PSO method described therein.

What caught my attention more was the simplicity of the PSO to understand and to program: only four easy equations describe the operation of the PSO algorithm. I did not waste any time, and I wrote my first PSO code on MATLAB®, and then tried some of the examples described in the above paper. I was so happy that my code worked and produced almost the same results. I tried it, with some modifications, on other mathematical benchmark examples, and it worked on those as well! Driven by this success, I decided to apply the PSO to a real-world problem: I chose the optimization of the geometry of a linear antenna array to reduce the sidelobe levels and to place nulls at desirable locations.

The results were very encouraging when compared with the results from classical optimization methods such the quadratic programming method (QPM). Our results were compiled in a paper, submitted to IEEE Transactions on Antennas & Propagation, where it was accepted and published fairly quickly. The most important and difficult part in the PSO algorithm is the definition and the calculation of the fitness function. Otherwise, any person with good programming skills can write his own PSO code in a matter of minutes to fit his specific problem.

Where do you see your research leading in the future?

Since the publication of our paper, I have been using the PSO to design and optimize many microwave devices, and the results have been (or are being) published in refereed journals and conference proceedings. Currently, I have two Master’s degree students under my supervision working on using the PSO, one in the area of designing other antenna arrays (planar, circular, Yagi-Uda, etc.), and the other in-power control for wireless communications. Both are advancing very well and doing state-of-the-art research, which hopefully will be published soon.

Do you foresee any social or political implications for your research?

The research I’m conducting is pure science with many practical applications in the areas of antennas and microwaves. I do not foresee it having a direct impact on political life, but it might affect the social life through enhancement of some of the products that people use each day, such as the cell phone.

Dr. Majid Khodier, Assistant Professor
Department of Electrical Engineering
Jordan University of Science and Technology
Irbid, Jordan
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