Reliability analysis of N-equations N-unknowns method for the solution of the finite-difference time-domain (FDTD) problems

Saydam T., Aksoy S.

Frequenz, vol.76, no.5, pp.331-335, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 76 Issue: 5
  • Publication Date: 2022
  • Doi Number: 10.1515/freq-2021-0140
  • Journal Name: Frequenz
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Compendex, INSPEC, RILM Abstracts of Music Literature
  • Page Numbers: pp.331-335
  • Keywords: finite difference time domain, high frequency (HF) range, speedup techniques, CONVERSIONS, FOURIER, FASTER
  • Kocaeli University Affiliated: No


© 2022 Walter de Gruyter GmbH, Berlin/Boston.Finite-difference time-domain (FDTD) solution of electromagnetic problems at high-frequency (HF) range is a challenging task. This is due to two requirements of accurate geometrical modeling for small objects/antennas and proper modeling of skin-depth effect. Generally, the fine meshes are used to overcome these problems. However, this leads to a large number of time iterations because of the small unit time step. To decrease the computational time, N-equations N-unknowns (NE-NU) method is developed for multi-frequency sources. Therefore, utilizing wideband nature of the FDTD method, NE-NU method is valuable. However, the reliability analysis of the NE-NU method has not been investigated in the literature. This study is the first numerical application of the NE-NU method that the reliability analysis of the NE-NU method is performed by using condition number calculation and it is validated by time-domain signals of an illustrative numerical example of a HF radar problem. A successful case and a failing case of the NE-NU method are clearly revealed. The effect of using a double-precision floating-point number and a single-precision floating-point number is also discussed. It is proved that a crucial value of the condition number can be found for the reliable NE-NU results.