Arama Sonuçları

Listeleniyor 1 - 2 / 2
  • Yayın
    Electromagnetic imaging of rough dielectric surface profiles using a single-frequency reverse time migration method
    (IEEE, 2023-07) Sefer, Ahmet; Yapar, Ali; Bağcı, Hakan
    An electromagnetic imaging scheme, which makes use of a single-frequency reverse time migration (RTM) technique to reconstruct two-dimensional (2D) rough surface profiles from the scattered field data, is formulated and implemented. The unknown surface profile, which is expressed as a one-dimensional height function, is the interface between two dielectric media. It is assumed that the profile is illuminated from one side and the scattered fields are “measured” along a line on this same side. RTM is used to construct a cross-correlation imaging functional that is numerically evaluated to yield an image of the investigation domain. The maxima of this functional yields an accurate reconstruction of the rough dielectric surface profile.
  • Yayın
    An Inverse recursive algorithm to retrieve the shape of the inaccessible dielectric objects
    (Ramazan YAMAN, 2024-10-16) Sefer, Ahmet
    A regularized electromagnetic iterative inverse algorithm is formulated and im-plemented to reconstruct the shape of 2D dielectric objects using the far-fieldpattern of the scattered field data. To achieve this, an integral operator thatmaps the unknown boundary of the object onto the far-field pattern of thescattered field is defined and solved for the unknown boundary. The addressedinverse problem has an ill-posed nature and inherits nonlinearity. To over-come these, the proposed solution is linearized via Newton and regularized byTikhonov in the sense of least squares. Besides, the dominance of the shadowregion in the inverse-imaging process is exceeded by considering the superpo-sition of multi-incoming plane waves, leading to less computational cost and avery fast inversion process. Comprehensive numerical analyses are carried outto ascertain the algorithm’s feasibility, revealing that it is very efficient andpromising.