In this paper, a new ultra wideband circular antenna array (UCAA) combining particle swarm optimizer (PSO) to minimize the bit error rate (BER) is proposed. The ultra wideband (UWB) impulse responses of the indoor channel for any transmitter-receiver location are computed by applying shooting and bouncing ray/image (SBR/Image) techniques, inverse fast Fourier transform and Hermitian processing. By using the impulse response of multipath channel, the BER performance of the binary pulse amplitude modulation (B-PAM) impulse radio (IR) UWB system can be calculated. Based on the topography of the circular antenna array, and the BER formula, the array pattern synthesis problem can be reformulated into an optimization problem and solved by the PSO. The novelties of our approach is not only choosing BER as the object function instead of sidelobe level of the antenna pattern, but also consider the antenna feed length effect of each array element. The strong point of the PSO is that it can find out the solution even if the performance index cannot be formulated by simple equations. Simulation results show that the synthesized antenna array pattern is effective to focus maximum gain to the LOS path which scales as the number of array elements. In other words, the receiver can increase the received signal energy to noise ratio. The synthesized array pattern also can mitigate severe multipath fading in complex propagation environment. As a result, the BER can be reduced substantially in indoor UWB communication system.
2. Ares, F. J., A. Rodriguez, E. Villanueva, and S. R. Rengarajan, "Genetic algorithms in the design and optimization of antenna array patterns," IEEE Trans. Antennas and Propagat., Vol. 47, 506-510, Mar. 1999.
3. Jiao, Y. C., W. Y. Wei, L. W. Huang, and H. S. Wu, "A new low-side-lobe pattern synthesis technique for conformal arrays," IEEE Trans. Antennas Propag., Vol. 41, 824-831, Jun. 1993.
4. Chen, C. H., C. C. Chiu, and C. L. Liu, "Novel directional radiation pattern by genetic algorithms in indoor wireless local loop," Wireless Personal Communications, Vol. 42, No. 4, 575-586, Sep. 2007.
5. Puskely, J. and Z. Novacek, "New look to real valued genetic algorithm used to reconstruct radiation patterns," 19th International Conference Radioelektronika'09, 299302, Apr. 22-23, 2009.
6. Chen, C. H., S. H. Liao, M. H. Ho, C. C. Chiu, and K. C. Chen, "A novel indoor UWB antenna array design by GA," International Conference on Future Computer and Communication, 291-295, Kuala Lumpur, Malaysia, Apr. 2009.
7. Guo, J. L. and J. Y. Li, "Pattern synthesis of conformal array antenna in the presence of platform using differential evolution algorithm," IEEE Trans. Antennas Propag., Vol. 57, No. 9, 2615-2621, Sep. 2009.
8. Gueguen, E., F. Thudor, and P. Chambelin, "A low cost UWB printed dipole antenna with high performance," IEEE International Conference on Ultra-wideband, 89-92, Sep. 2005.
9. Kennedy, J. and R. Eberhart, "Particle swarm optimization," Proceedings of the IEEE International Conference on Neural Networks, 1942-1948, 1995.