Electricall Small, e.g. communication antennas on aircraft.
Electrically Large, e.g. mobile phone with Bluetooth enabled in a car.
Electrically Huge, e.g. radar antenna on ship with UTD rays shown.

Problem Description

Many techniques exist for the simulation of antennas in free-space. In practice such antennas are mounted on physical structures which significantly influences their free-space radiation characteristics. Measurements of the radiation characteristics of an antenna mounted on a large platform is difficult or even impossible to perform and the challenge therefore exists to accurately simulate the interaction of an antenna with electrically large environments.

FEKO Solution
FEKO divides antenna placement problems into the following catagories, based on the electrical size of the structures that interact with the antenna:

• Electrically small problems of only a few wavelengths, which may be solved with the Method of Moments (MoM).
  
• Electrically large problems, which may be solved with the:
• • Multilevel Fast Multipole Method (MLFMM) which offers accuracy comparable with that of the MoM, but with an implementation that requires significantly less computational resources.
  • Hybrid Method of Moments / Physical Optics (MoM/PO).
    
• Electrically huge problems, which may be solved with the hybrid Method of Moments / Uniform Theory of Diffraction (MoM/UTD) technique.