Utilization of Multiple Huygens Surfaces in Ray Tracing Scenarios Involving Diffractions

An electromagnetic ray tracing framework that utilizes multiple Huygens surfaces is presented and evaluated. The Huygens surfaces introduced in this method partition large and complex propagation environments into smaller and simpler subdomains, confining rays to propagate only within those subdomains. The cross-domain propagation is achieved through the use of Huygens integrals for the fields associated with rays captured on the Huygens surfaces. This method enables the original problem to be tackled in a step-by-step manner, providing three significant advantages: 1) reduced ray-miss errors due to shorter propagation distances and larger Huygens surfaces compared to conventional reception spheres, 2) reduced or eliminated the need for sequential uniform theory of diffraction (UTD) evaluations, and 3) reuse of intermediate results to enable subdomain changes without redoing the entire simulation. Moreover, this approach allows for bidirectional ray launching, enabling rays to be launched from the receiver to an already-illuminated Huygens surface, resulting in greater flexibility and potentially improved accuracy. By employing intelligent ray launching strategies and rapidly converging integration techniques, this method can accurately evaluate many successive diffractions. The implementation is GPU-based, facilitating massively parallelized simulations.