Corner Reflector (FDTD Animation)

Two corner reflectors with two different tilt angles have been simulated for demonstrating their reflection properties. The simulations are rendered using the total-field/scattered-field finite-difference time-domain algorithm. An identical incoming plane wave in the negative vertical direction hits the corner reflectors. Although having different tilt angles, they reflect the incoming way in the same positive vertical direction. Corner reflectors are known to be retro-reflectors and consists of 2 or more mutually perpendicular and intersecting flat surfaces. They automatically reflect the waves back towards to the source. In practice, they are used for calibration purposes (e.g. meteorological radars) and range detection. Also in maritime and air navigation, they are used to mark the desired objects on the radar screen (e.g. buoys, ships, runways etc). Corner reflectors are also used to as safety reflectors for cars, bikes, traffic signs and similar devices. Here, the reflectors are in the passive mode, but can also be used in semi-active mode to enhance the directivity of dipole antennas. Basically, by placing the dipole antenna in front of a corner reflector, the combined corner-reflector dipole antenna has a better directivity.

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).

FDTD Simulation of a Half Convex Lens

Finite-difference time-domain (FDTD) simulation of a half convex lens when a point source is located at its focal plane in both on-axis (left) and off-axis (right) cases. The points indicated by the small circle are the actual source locations and the third point with the cross sign is the location of symmetry for the off-axis source.

The source locations are located at the focal plane to demonstrate the collimation property of the lenses. Again, to demonstrate the frequency independency of the lens behavior, two short pulses at different central frequencies are fired consecutively and both cases show collimation after exiting the lens.

The lens employed here has a parabolic surface and obviously, it is not perfectly optimized hence the directed signals are not perfectly smooth. For desired far field performance the shape of the lens can be further designed using optimization algorithms integrated with electromagnetic solvers.

Two related papers are:
1) A. V. Boriskin, A. Rolland, R. Sauleau and A. I. Nosich, Assessment of FDTD Accuracy in the Compact Hemielliptic Dielectric Lens Antenna Analysis, IEEE Trans. Antennas and Prop. vol.56, no.3 pp. 758-764, March 2008
2) G. Godi, R. Sauleau and D. Thouroude, Performance of Reduced Size Substrate Lens Antennas for Millimeter-Wave Communications, IEEE Trans. Antennas and Prop. vol.53, no.4 pp. 1278-1286, April 2005

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

Dish Antenna Animation (Parabolic reflector)

Finite-difference time-domain (FDTD) simulation of a parabolic reflector antenna in the transmitting phase. Reflector antennas are frequency-independent antennas and they are highly directive. As long as the source is located at the focal point, the reflected field travels in the broadside direction. In this simulation, two short pulses - first one at central frequency of 100 MHz and the other at 200 MHz are fired from the focal point (VHF regime). f/D (focal length/diameter) ratio is 0.257.

Normally, the feed antenna is also chosen to be directive, but for the purpose of illustration, we have chosen a point source as the feed antenna.

Below, one can see several microwave link stations in the form of dish antennas (Photo captured in Mount Hood in Oregon around 7000 ft).

Also see below for other simulations:

Half Wavelength Dipole Antenna Radiation
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