Browsing by Subject "Absorbing boundary conditions (ABC)"

Now showing 1 - 3 of 3

Open Access
Accurate plane-wave excitation in the FDTD method
(IEEE, 1997) Gürel, Levent; Oğuz, Uğur; Arıkan, Orhan
Different techniques are developed to implement plane-wave excitation on the finite-difference time-domain (FDTD) method, such as the initial-condition, the hard-source, and the connecting-condition techniques, for the total-field/scattered field (TF/SF) formulation. In the TF/SF formulation, the incident field is computed and fed to the 3D FDTD grid on the boundary separating the total-field and the scattered-field regions. Since the incedent field is a known quantity, a closed-form expression can be evaluated on every point of this boundary. A more efficient way of computing the incedent field is by using an incedent-field array (IFA), which is a 1D FDTD grid set-up to numerically propagate the incedent field into the 3D FDTD.
Open Access
Simulation of TRT-configured ground-penetrating radars over heterogeneous grounds
(IEEE, 2001) Oǧuz, Uğur; Gürel, Levent
The simulation of transmitter-reciever-transmitter (TRT) configured ground-penetrating radars over heterogeneous grounds was discussed. The finite-difference time-domain (FDTD) methods along with the perfectly-matched layer (PML) absorbing boundary conditions (ABC) were used for the simulations. Scattered-field image demonstrated that the buried target was easily detected when buried in a homogenous ground. Results show that the TRT-configured GPR is sensitive to surface roughness and the main source of noise is the detoriorations in the ground-air interface.
Open Access
Subsurface-scattering calculations via the 3D FDTD method employing PML ABC for layered media
(IEEE, 1997) Oğuz, Uğur; Gürel, Levent
A three-dimensional finite-difference time-domain method that employs pure scattered-field formulation and perfectly matched layers (PML) as the absorbing boundary condition is developed for solving subsurface-scattering. A subsurface radar is modeled and the fields scattered from various buried objects with different parameters such as the size, depth, and number are observed and distinguished. The `derivative' signal, which can easily be obtained in practical systems, is useful in identifying the buried objects.