To demonstrate the utility of Geometrical Theory of Diffraction solver simulation in newFasant for models that include scatterers with curved surfaces.



Introduction:

newFASANT complements Altair’s high frequency electromagnetic software tool Altair Feko for general 3D EM field calculations. Advanced solver technologies like Method of Moments (MoM) with macro basis functions (CBFM), Physical Optics (PO)/ Geometrical Optics (GO)/ Physical Theory of Diffraction (PTD), Geometrical Theory of Diffraction/Physical Optics (GTD/PO), and Multi Level Fast Multipole Method (MLFMM) parallelized through MPI/OpenMP, being some of them very efficient to analyze electrically very large problems

The Geometrical Theory of Diffraction (GTD) is a well-accepted asymptotic method. GTD has many advantages to calculate fields in the shadow regions. GTD can be used for antenna placement analysis and coverage parameters for radio communication systems. Below, we present a short video demo of the workflow to use GTD in newFASANT using a dipole antenna in the presence of a conducting sphere over a ground plane.

 

Problem Setup: Dipole Antenna and Conducting Sphere Over a Ground Plane at 1 GHz.


A dipole antenna and conducting sphere (radius of 3λ with the center located at (8.5λ, 0, 5λ)) are placed above 5 wavelengths above a finite ground plane as shown below.


Results:


 A far field pattern result along theta cut has been requested. Figure below depicts the far field pattern along theta cut. Figure 3 depicts the direct, reflected, and creeping waves of the dipole antenna and scattered conducting sphere above the ground plane



A detailed step by step instructions on this tutorial is presented in the below video.