A Multiple Huygens Surface Based Ray Tracing Framework with GPU Acceleration

A ray tracing framework based on the utilization of multiple Huygens surfaces is introduced and evaluated. As such, complex propagation environments are divided into smaller subdomains, thereby restricting rays to traverse within a smaller, simpler space. The subdomains are surrounded by the Huygens surfaces and equivalent Huygens sources interconnect the ray based field representations in neighboring subdomains. Compared to conventional shooting and bouncing rays (SBR) based ray tracing simulations, which rely on reception spheres to identify ray hits, this approach reduces the errors caused by ray misses, because Huygens surfaces can have larger sizes than reception spheres, and rays need to travel shorter distances within each subdomain. Related to diffraction computations, which rely conventionally on the uniform theory of diffraction (UTD), the flexibility of choosing Huygens surfaces allows to separate diffraction edges into different subdomains, thus, eliminating the need for consecutive UTD evaluations and the corresponding exponential increase in the number of diffracted rays. Together with smart ray launching strategies and quickly converging integration methods, the presented approach allows to evaluate more than 10 successive diffractions with reasonable accuracy. The implementation is based on graphics processing units (GPUs), which enable massively parallelized simulations.