General Applicability of the Technique

Ray launching through a lens.

GO for dielectrics is formulated for use in instances where electrically very large (> 20 λ) dielectric structures are modelled. GO is a ray-based technique that models dielectric objects based on optical propagation, reflection and refraction theory. Users will typically attempt a MoM solution for structures involving dielectric object at first and when they realise that the structure is electrically too large to solve using available resources (platform memory, time) they will turn to MLFMM and then GO.

Technical Foundation (Hybrid MoM/GO)

FEKO integrates the GO method with the current-based MoM, by launching rays from each radiating MoM element. The ray-interactions with dielectric structures are then modelled using Huygens sources placed on each ray-contact point (reflected, refracted and transmitted rays) on the dielectric boundaries. The ray-launching process is easily controlled based on the angular spacing of the rays and the number of interactions to be taken into account.

Typical ray launching path.

FEKO segments a GO region triangularly, in exactly the same manner used for MoM and PO solutions, making it a simple task to switch between solution options. GO triangles may, however, be electrically much larger than for MoM modelling (limited only by the accuracy of the geometry representation), potentially resulting in a large reduction in mesh storage requirements.

Typical Application of the GO

A typical application of how the MoM/GO hybrid method can be employed with good effect is in the analysis of lenses. The source structure, e.g. a metallic antenna under a lens, may be modelled with the MoM and the large dielectric lens may be modelled with the GO.

Lens modelling with dielectric GO.