The aim of this workis to increase the instability of the marching-on-in-time (MOT) method that is used in the analysis of wide-band electromagnetic pulse scattering from structures made of thin wires. The stability problem has been identified with the advent of the MOT method in 1991, and although several improvements have been suggested to overcome this difficulty no exact solution has been found [1]. In this thesis two methods (the Newmark-Beta formulation and the analytic integration) to suppress the instabilities of the MOT algorithm for thin wire scatterers have been proposed and their effects on the stability have been inspected. The results are compared with the results obtained with time domain method of moments (MOM) [2] and it is observed that the results are both stable and accurate. It is shown how the stability is changed by a determined β parameter. Also, Newmark-Beta formulation results for selected different types of structures such as dipole antenna illuminated by a Gaussian pulse given in [3], three pole structure given in [4], loop antenna given in [3] has been shown.
2. Ozsoy, S., Ince tellerden olusan yapılardan sacılma analizi ıcin zamana ve frekansa baglııki cozucu, Gebze Institute of Technology, 2003.
3. Ji, Z., T. K. Sarkar, B. H. Jung, Y. S. Chung, M. Salazar-Palma, and M. Yuan, "A stable solution of time domain electric field integral equation for thin-wire antennas using the Laguerre polynomials," IEEE Trans. Antennas Propagat., Vol. 52, 2641-2649, 2004.
doi:10.1049/ip-map:20045113
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9. Sadigh, A. and E. Arvas, "Treating the instability in matching-on-in-time method from a different perspective," IEEE Trans. Antennas Propagat., Vol. 41, 1993.
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11. Hu, J. L., C. H. Chan, and Y. Xu, "A new temporal basis function for the time-domain integral equation method," IEEE Microwave and Wireless Communications, Vol. 11, No. 11, 2001.
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12. Wang, Y. and T. Itoh, "Envelope-Finite-Element (EVFE) technique a more efficient time-domain scheme," IEEE Transactions on Microwave Theory and Techniques, Vol. 49, 2241-2247, 2001.
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13. Manara, G., A. Monorchio, and R. Reggiannini, "A space-time discretization criterion for a stable time-marching solution of the electric field integral equation," IEEE Trans. Antennas Propagat., Vol. 45, 527-532, 1997.
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