In this paper, we propose an enhancement of the Equivalent Circuit Method (ECM) for analysis of frequency selective surface (FSS) with square loop geometry of the unit cell. For this, genetic algorithms and rational algebraic models are used to obtain a more accurate value of the effective electrical permittivity (εeff). We use simulated data obtained with a commercial software to adjust some parameters. So, genetic algorithm is used to obtain a better value of an exponent that calculates εeff minimizing the rational algebraic models. In this paper, this is done for the square loop geometry, but the methodology can be extended to any geometry. Finally, prototypes are built and the technique is validated.
2. Harms, P., R. Mittra, and W. Ko, "Implementation of the periodic boundary condition in the finite-difference time-domain algorithm for FSS structures," IEEE Transactions on Antennas and Propagation, Vol. 42, No. 9, 1317-1324, 1994.
doi:10.1109/8.318653
3. Weile, D. S., E. Michielssen, and K. Gallivan, "Reduced order modeling of multiscreen frequency selective surfaces using Krylov-based rational interpolation," IEEE Transactions on Antennas and Propagation, Vol. 49, No. 5, 801-813, 2001.
doi:10.1109/8.929635
4. Silva, P. H. F. and A. L. P. S. Campos, "Fast and accurate modelling of frequency-selective surfaces using a new modular neural network configuration of multilayer perceptrons," IET Microwave Antennas & Propagation, Vol. 2, No. 5, 503-511, 2008.
doi:10.1049/iet-map:20080066
5. Yilmaz, A. E. and M. Kuzuoglu, "Design of the square loop frequency selective surfaces with particle swarm optimization via the equivalent circuit model," Radioengineering, Vol. 18, No. 2, 95-102, 2009.
6. Genovesi, S., R. Mittra, A. Monorchio, and G. Manara, "Particle swarm optimization for the design of frequency selective surfaces," IEEE Antennas and Wireless Propagation Letters, Vol. 5, No. 1, 277-279, 2006.
doi:10.1109/LAWP.2006.875900
7. Silva, M. R., C. L. Nóbrega, P. H. F. Silva, and A. G. d’Assunção, "Optimization of FSS with Sierpinski island fractal elements using population-based search algorithms and MLP neural network," Microwave and Optical Technology Letters, Vol. 56, No. 4, 827-831, 2014.
doi:10.1002/mop.28214
8. Campos, A. L. P. S., A. M. Martins, and V. A. Almeida Filho, "Synthesis of frequency selective surfaces using genetic algorithm combined with the equivalent circuit method," Microwave and Optical Technology Letters, Vol. 54, No. 8, 1893-1897, 2012.
doi:10.1002/mop.26953
9. Araújo, W. C., H. W. C. Lins, A. G. d’Assunção, and J. L. G. Medeiros, "A bioinspired hybrid optimization algorithm for designing broadband frequency selective surfaces," Microwave and Optical Technology Letters, Vol. 56, No. 2, 329-333, 2014.
doi:10.1002/mop.28043
10. Marcuvitz, N., Waveguide Handbook, McGraw-Hill, New York, 1951.
11. Langley, R. J. and E. A. Parker, "Equivalent circuit model for arrays of square loops," Electronics Letters, Vol. 18, No. 7, 294-296, 1982.
doi:10.1049/el:19820201
12. Lee, C. K. and R. J. Langley, "Equivalent circuit models for frequency selective surfaces at oblique angles of incidence," IEE Proceedings, Vol. 132, No. 6, 395-399, 1985.
13. Wang, Z. L., K. Hashimoto, N. Shinohara, and H. Matsumoto, "Frequency-selective surface for microwave power transmission," IEEE Transactions on Microwave Theory and Techniques, Vol. 47, No. 10, 2039-2042, 1999.
doi:10.1109/22.795083
14. Langley, R. J. and E. A. Parker, "Double-square frequency selective surfaces and their equivalent circuit," Electronics Letters, Vol. 19, No. 17, 675-677, 1983.
doi:10.1049/el:19830460
15. Leonard, T. W. and J. W. Cofer, "A new equivalent circuit representation for the Jerusalem cross," IEE Conference Publ., Vol. 169, 65-69, 1978.
16. Langley, R. J. and A. J. Drinkwater, "Improved empirical model for the Jerusalem cross," IEE Proceedings, Vol. 129, No. 1, 1-6, 1982.
doi:10.1049/ip-d.1982.0001
17. Costa, F., A. Monorchio, and G. Manara, "Efficient analysis of frequency-selective surfaces by a simple equivalent-circuit model," IEEE Antennas and Propagation Magazine, Vol. 54, No. 4, 36-48, 2012.
doi:10.1109/MAP.2012.6309153
18. Yatsenko, V. V., S. A. Tretyakov, S. I. Maslovski, and A. A. Sochava, "Higher order impedance boundary conditions for sparse wire grids," IEEE Transactions on Antennas and Propagation, Vol. 48, No. 5, 720-727, 2000.
doi:10.1109/8.855490
19. Conrad, B., Differential geometry handouts, Stanford University, Available at: http://math.stanford.edu/∼conrad/diffgeomPage/handouts.html.
Submit
