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