Ground Penetrating Radar (GPR) B-Scan Collection (FDTD Animation )

Here, B-scan data collection of a simple ground penetrating radar (GPR) is animated through the use of Finite-difference time-domain (FDTD) method. The upper part of the animation shows the 2D spatial propagation of the short pulse transmitted from the antenna at different spatial locations. The transmitting antenna shoots a short electromagnetic pulse (with a central frequency of 600 MHz) into the subsurface where the relative dielectric permittivity is 4. The short pulse is reflected from the air-soil interface and then from the target embedded in the subsurface. Then, the scattered signals are recorded by the same antenna in the receiving mode. The lower part of the animation corresponds to the received signals (A-scan) at the same antenna for each of the positions. This constitutes the so-called B-scan data collection.

Phased Array Beam Steering Animation

Beam steering via phased antenna arrays is demonstrated. The arrays are  composed of 7 point sources uniformly spaced in a linear fashion (uniform linear array (ULA). The antenna separation is denoted by the parameter d. When the separation is smaller, the directivity of the array is narrower. Each antenna element in the array is fed with a relative phase shift of "delta" with respect to the adjacent on (the rightmost antenna is the reference antenna where no phase shift is applied, i.e. delta=0).

Effect of Perfectly Matched Layers (PML) in FDTD Simulations

Although it is pretty straightforward for researchers in the field of modeling via FDTD or FEM, PML can puzzle those who do not have any modeling background. Therefore, here we try to simply show what happens with and without a PML in a free space propagation modeling.

Basically, we demonstrate the effects of the perfectly matched layers in finite-difference time-domain (FDTD) simulations. Here, a point source transmits a spherical wave and the simulation domain is truncated in two different ways. In the first case (left one) no PML region is utilized whereas in the second one (right) PML region is included. It is clearly observed that PML absorbs the incoming waves mimicking a infinite domain simulation whereas the simulation without PML, spurious reflections occur due to termination of the computational boundary.

Periodic Band Gap (PGB) Waveguide and Propagation - FDTD Simulation

Inspired by the following video:
http://www.youtube.com/watch?v=O-6l0bvAda0

Guiding EM waves via periodic structure. The frequency of operation is 11.085 GHz. The relative dielectric permittivity of the square blocks are 11.56 and the ambient medium is air. Each block is 3.5 mm x 3.5 mm.

The main reference is the below dissertation:
Marcelo Bruno Dias, "Estudo da Propagação de Ondas Eletromagnéticas em Estruturas Periódicas". Graduation Dissertation - Electrical Engineering Course, Universidade Federal do Pará (UFPA), Belém, Pará Brazil, 2003.

More details can be found in their lab web site:
www.lane.ufpa.br/publicacoes.html

Standing Wave Pattern

Uniform plane wave traveling in the +z direction and normally incident on a medium interface at z=0. Only the electric field intensity is shown.
The top figure shows the incident (blue), reflected (red), incident+reflected (brown) and transmitted field in both media. In the bottom figure, the standing wave patterns created in both media are shown.

Also see below:
Oblique Plane Wave Reflection From Half Space
Radiation from a Circularly Tapered Dielectric Waveguide
Right Hand Circular Polarization (RHCP) Animation
Linear Polarization Animation
Left Hand Elliptical Polarization (LHEP) Animation
Standing Wave Pattern (SWR) Animation
Electromagnetic Propagation of UWB Short Pulse in Random Medium 
Half Wavelength Dipole Antenna Radiation 
Dipole Antenna Radiation 
Dish Antenna Animation (Parabolic reflector) 
FDTD Simulation of a Half Convex Lens

Right Hand Circular Polarization (RHCP) Animation

Uniform plane wave traveling in +z direction

Also see below:
Oblique Plane Wave Reflection From Half Space

Radiation from a Circularly Tapered Dielectric Waveguide

Right Hand Circular Polarization (RHCP) Animation

Linear Polarization Animation

Left Hand Elliptical Polarization (LHEP) Animation

Standing Wave Pattern (SWR) Animation

Electromagnetic Propagation of UWB Short Pulse in Random Medium

Dipole Antenna Radiation

Dipole Antenna Radiation

Finite-difference time-domain (FDTD) simulation of a 2 wavelengths long dipole antenna at 400 MHz in free space. The radiation pattern is very different than that of the traditional half-wavelength dipole antenna. Nulls in the broadside and endpoints are clearly visible

Dish Antenna Animation (Parabolic reflector)