Time-Domain Shooting and Bouncing Rays Method Based on Beam Tracing Technique

An efficient time-domain shooting and bouncing ray (TD-SBR) method is developed to analyze the transient scattering responses from large perfectly conducting objects illuminated by a pulsed plane wave. Differing from the conventional TD-SBR method, a beam tracing (BT) technique, instead of the ray tracing (RT), is first employed in the TD-SBR method, which provides much simpler procedure to avoid the divergence problem in the conventional SBR that happens when ray tubes intersecting discontinuous parts of the object. Applying a strategy of equivalent incident reference plane, alternative closed-form formulas are derived in the transient electromagnetic (EM) computations. Based on the closed-form representations, the characteristics of transition function and scattered fields are further investigated to show the physical phenomenon of scattering mechanisms. Due to the causality of transient fields, the proposed formulas are more efficient in EM calculations than the conventional frequency-domain formulas. Numerical examples illustrate that the BT technique can greatly improve the accuracy of the TD-SBR method, and the computational efficiency is enhanced significantly by using the direct TD formulas.