Browsing by Subject "Subsurface scattering"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Open Access Optimization of the transmitter-receiver separation in the ground-penetrating radar(IEEE, 2003-03) Gürel, Levent; Oğuz, U.The finite-difference time-domain method is applied to simulate three-dimensional subsurface-scattering problems, involving a ground-penetrating-radar (GPR) model consisting of two transmitters and a receiver. The receiving antenna is located in the middle of the twos identical transmitters, which are fed 180degrees out of phase. This configuration implies the existence of a symmetry plane in the middle of two transmitters and the cancellation of the direct signals coupled from the transmitters at the receiver location. The antenna polarizations and their separations are arbitrary. The transmitter-receiver-transmitter configured GPR model is optimized in terms of the scattered energy observed at the receiver by varying the antenna separation. Many simulation results are used to demonstrate the effects of the antenna separation and the optimal separation encountered for a specific target and GPR scenario.Item Open Access Simulations of ground-penetrating radars over lossy and heterogeneous grounds(IEEE, 2001) Gürel, Levent; Oğuz, U.The versatility of the three-dimensional (3-D) finite-difference time-domain (FDTD) method to model arbitrarily inhomogeneous geometries is exploited to simulate realistic groundpenetrating radar (GPR) scenarios for the purpose of assisting the subsequent designs of high-performance GPR hardware and software. The buried targets are modeled by conducting and dielectric prisms and disks. The ground model is implemented as lossy with surface roughness, and containing numerous inhomogeneities of arbitrary permittivities, conductivities, sizes, and locations. The impact of such an inhomogeneous ground model on the GPR signal is demonstrated. A simple detection algorithm is introduced and used to process these GPR signals. In addition to the transmitting and receiving antennas, the GPR unit is modeled with conducting and absorbing shield walls, which are employed to reduce the direct coupling to the receiver. Perfectly matched layer absorbing boundary condition is used for both simulating the physical absorbers inside the FDTD computational domain and terminating the lossy and layered background medium at the borders.Item Open Access Three-dimensional FDTD modeling of a ground-penetrating radar(IEEE, 2000) Gürel, Levent; Oğuz, U.The finite-difference time-domain (FDTD) method is used to simulate three-dimensional (3-D) geometries of realistic ground-penetrating radar (GPR) scenarios. The radar unit is modeled with two transmitters and a receiver in order to cancel the direct signals emitted by the two transmitters at the receiver. The transmitting and receiving antennas are allowed to have arbitrary polarizations. Single or multiple dielectric and conducting buried targets are simulated. The buried objects are modeled as rectangular prisms and cylindrical disks. Perfectly-matched layer absorbing boundary conditions are adapted and used to terminate the FDTD computational domain, which contains a layered medium due to the ground-air interface.Item Open Access Transmitter-receiver-transmitter configurations of ground-penetrating radar(Wiley-Blackwell Publishing, Inc., 2002) Gürel, Levent; Oğuz, U.Three-dimensional ground-penetrating radar (GPR) geometries are simulated using the finite difference time domain (FDTD) method. The GPR is modeled with a receiver and two transmitters with arbitrary polarizations in order to cancel the direct signals emitted by the two transmitters at the receiver. This GPR configuration is used to simulate scenarios involving single or multiple targets with arbitrary sizes. The buried objects are modeled as cylindrical disks. Perfectly matched layer absorbing boundary conditions are used to terminate the layered FDTD computational domain.