Shooting and bouncing rays

The first step in the SBR method is to use geometrical optics (GO, ray-tracing) for computing equivalent currents, either on metallic structures or on an exit aperture. The scattered field is thereafter computed by integrating these currents using physical optics (PO), by the Kirchhoff's diffraction formula. The current ${\displaystyle {\vec {J}}}$ on a perfect electrical conductor (PEC) is related to the incident magnetic field ${\displaystyle {\vec {H}}_{i}}$ by ${\displaystyle {\vec {J}}=2{\hat {n}}\times {\vec {H}}_{i}}$. This approximation holds best for short wavelengths, and it assumes that the radius of curvature of the scatterer is large compared to the wavelength.[2]

The SBR method is implemented in the following commercial codes:

• Altair Feko (method there known as RL-GO - Ray Launching Geometrical Optics)
• CST Microwave Studio, Asymptotic Solver
• Ansys HFSS SBR+, previously Delcross Savant
• XGTD

• Computational electromagnetics