The improved ultra-wide band characteristic basis function method (IUCBFM) is an efficient approach to analyze the wide-band scattering problems because the improved ultra-wide characteristic basis functions (IUCBFs) can be reused for any frequency sample in the range of interest. However, the number of the IUCBFs constructed at the highest frequency point is excessive, and the computational complexity will be increased when applying the same number of IUCBFs at the lower frequency points. To mitigate this problem, an adaptive IUCBFs construction method is presented which can decrease the computational complexity at the lower frequency points. In the proposed method, the given frequency band is adaptively divided into multiple sub-bands in consideration of the number of the IUCBFs. The adaptive IUCBFs are obtained at the highest frequency point in each sub-band, which leads to smaller number of IUCBFs and significant reduction of solver time at lower frequency band. The numerical results have demonstrated the accuracy and efficiency of the proposed method.
2. Coifman, R., V. Rokhlin, and S. Wandzura, "The fast multipole method for the wave equation: A pedestrian prescription," IEEE Ant. Propag. Mag., Vol. 53, No. 3, 7-12, 1993.
3. Song, J. M., C. C. Lu, and W. C. Chew, "Multilevel fast multipole algorithm for electromagnetic scattering by large complex objects," IEEE Trans. Antennas Propag., Vol. 45, No. 10, 1488-1493, 1997.
4. Chen, M., R. S. Chen, and X. Q. Hu, "Augmented MLFMM for analysis of scattering from PEC object with fine structures," Applied Computational Electromagnetics Society (ACES) Journal, Vol. 26, No. 5, 418-428, 2011.
5. Bleszynski, E., M. Bleszynski, and T. Jaroszewicz, "Adaptive integral method for solving large-scale electromagnetic scattering and radiation problems," Radio Sci., Vol. 31, No. 5, 1225-1251, 1996.
6. Zhao, K., M. N. Vouvakis, and J.-F. Lee, "The adaptive cross approximation algorithm for accelerated method of moments computations of EMC," IEEE Trans. Electromagn. Compat., Vol. 47, No. 4, 763-773, 2005.
7. Prakash, V. V. S. and R. Mittra, "Characteristic basis function method: A new technique for efficient solution of method of moments matrix equations," Microw. Opt. Technol. Lett., Vol. 36, No. 2, 95-100, 2003.
8. Lucente, E., A. Monorchio, and R. Mittra, "An iteration free MoM approach based on excitation independent characteristic basis functions for solving large multiscale electromagnetic scattering problems," IEEE Trans. Antennas Propag., Vol. 56, No. 4, 999-1007, 2008.
9. Burke, G. J., "Using model based parameter estimation to increase the efficiency of computing electromagnetic transfer functions," IEEE Trans. Mag., Vol. 25, 2807-2809, 1988.
10. Newman, E. H., "Generation of wide band from the method of moments by interpolating the impedance matrix," IEEE Trans. Antennas Propag., Vol. 36, 1820-1824, 1988.
11. Reddy, C. J., M. D. Deshpande, and C. R. Cockrell, "Fast RCS computation over a frequency band using method of moments in conjunction with asymptotic evaluation technique," IEEE Trans. Antennas Propag., Vol. 46, No. 8, 1229-1233, 1998.
12. Wang, X., S. X. Gong, and J. L. Guo, "Fast and accurate wide-band analysis of antennas mounted on conducting platform using AIM and asymptotic waveform evaluation technique," IEEE Trans. Antennas Propag., Vol. 59, No. 12, 4624-4633, 2011.
13. Sun, Y. F., Y. Du, and Y. Sao, "Fast computation of wideband RCS using characteristic basis function method and asymptotic waveform evaluation technique," Journal of Electronics (in Chinese), Vol. 27, No. 4, 463-467, 2010.
14. Han, G. D., Y. H. Pan, and B. F. He, "Fast analysis for 3D wide-band & wide-angle electromagnetic scattering characteristic by AMCBFM-MBPE," Journal of Microwaves, Vol. 25, No. 6, 32-37, 2009.
15. Degiorgi, M., G. Tiberi, and A. Monorchio, "Solution of wide band scattering problems using the characteristic basis function method," IET Microwaves Antennas and Propagation, Vol. 6, No. 1, 60-66, 2012.
16. Zhang, M. Y., Y. F. Sun, and Z. G. Wang, "Solutions of broadband RCS using the characteristic basis function method," IEEE MTTS International Wireless Symposium, 1-4, Mar. 2015.
17. Nie, W. Y. and Z. G. Wang, "Solution for wide band scattering problems by using the improved ultra-wide band characteristic basis function method," Progress In Electromagnetics Research Letters, Vol. 58, 37-43, 2016.
18. Tsang, L., C. E. Mandt, and D. H. Ding, "Monte Carlo simulations of the extinction rate of dense media with randomly distributed dielectric spheres based on solution of Maxwell’s equations," Optics Letters, Vol. 17, No. 5, 314-316, 1992.
19. Wang, Z. G., Y. F. Sun, and G. H. Wang, "Analysis of electromagnetic scattering from perfect electric conducting targets using improved characteristic basis function method and fast dipole method," Journal of Electromagnetic Waves and Applications, Vol. 28, No. 7, 893-902, 2014.