Radiation pattern analysis for scattering of arbitrary beams by arbitrary particles

In optical-band antenna systems, scatterers with arbitrary geometric structures are ubiquitous in natural environments. When their dimensions are comparable to the wavelength, the resulting scattering effects can significantly distort radiation characteristics. Different beam types-such as Gaussian, Bessel, and Airy beams-exhibit distinct propagation behaviors, and their interaction with complex scatterer geometries demands a general and flexible scattering analysis framework capable of handling arbitrary beam-particle combinations. To address this need, we extend DDSCAT to support externally defined structured beams, enabling scattering and absorption simulations for arbitrary particles under arbitrary beam illumination. The model is systematically validated against both Generalized Lorenz-Mie theory (for spherical particles) and COMSOL Multiphysics (for irregular particles), showing good agreement across all validation cases. This work advances the understanding of light-matter interactions in complex optical environments and provides an efficient simulation tool for electromagnetic compatibility, channel characterization, and optical antenna design.