Shooting and bouncing rays

<h2 id="theory">Theory</h2>
<p>The first step in the SBR method is to use <a href="/facts/Geometrical_optics/gIFu84Tm">geometrical optics</a> (GO, <a href="/facts/Ray_tracing_(physics)/VKdjk6Sc">ray-tracing</a>) for computing equivalent currents, either on metallic structures or on an exit aperture. The scattered field is thereafter computed by integrating these currents using <a href="/facts/Physical_optics/Al5EFMyy">physical optics</a> (PO), by the <a href="/facts/Kirchhoff%2527s_diffraction_formula/GC5spAeK">Kirchhoff's diffraction formula</a>. The current 
  
    
      
        
          
            
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    {\displaystyle {\vec {J}}}
  
 on a perfect electrical conductor (PEC) is related to the incident magnetic field 
  
    
      
        
          
            
              
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    {\displaystyle {\vec {H}}_{i}}
  
 by 
  
    
      
        
          
            
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    {\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.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p>
<h3>Extending SBR for edge diffraction</h3>
<p>Since the approximation described above assumes that the radius of curvature is large compared to the wavelength, the <a href="/facts/Diffraction/Mk80xXHT">diffraction</a> from edges needs to be handled separately. The SBR method can be extended with physical theory of diffraction (PTD) in order to include edge diffraction in the model.
</p>
<h2 id="implementation-in-commercial-software">Implementation in commercial software</h2>
<p>The SBR method is implemented in the following commercial codes: 
</p>
<ul><li>Altair Feko (method there known as RL-GO - Ray Launching Geometrical Optics)</li>
<li>CST Microwave Studio, Asymptotic Solver</li>
<li>Ansys HFSS SBR+, previously Delcross Savant</li>
<li>XGTD</li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Computational_electromagnetics/uJKnwCar">Computational electromagnetics</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Ling, Hao; et al. (1989). "Shooting and bouncing rays: calculating the RCS of an arbitrarily shaped cavity". IEEE Transactions on Antennas and Propagation. 37 (2): 194. Bibcode:1989ITAP...37..194L. doi:10.1109/8.18706. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Kristensson, Gerhard (2016). Scattering of electromagnetic waves by obstacles. Scitech. p. 295. ISBN 978-1-61353-222-5. <a href="978-1-61353-222-5" target="_blank">978-1-61353-222-5</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
</ol>

Shooting and bouncing rays open-in-new

Shooting and bouncing rays