Two Dimensional Frequency-angle Domain Interpolation Method for Electromagnetic Scattering Analysis of Precipitation Particles

In recent years, in applications related to the remote sensing of the environment, the research on characterization of the electromagnetic wave interaction with complex rainfall particles is of great importance. Several analytical methods based on wave theory, such as quasi-crystalline approximation, are frequently used. However, these approaches are not able to capture the essential physics of many real world problems. The alternative method to deal with scattering of complex rainfall particles is resort to numerical technologies, for instance, the method of moment (MoM). The MoM can provide precise solution of complex media scattering, while the main disadvantages of MoM are significant calculation time and huge memory requirements for the storage of impedance matrix. In order to alleviate these bottlenecks, a fast numerical method, which is called Sparse-Matrix/Canonical Grid (SM/CG) method, is proposed as an efficient method for calculating the scattering from three-dimensional dense media. To obtain the scattering over a frequency- and angular-band using SM/CG, one has to repeat the calculations at each frequency and angle over the band of interest. This can be computationally prohibitive despite the increased power of the present generation of computers. In order to alleviate this difficulty, a hybrid 2-D interpolation method is proposed for the efficient electromagnetic scattering analysis of precipitation particles over a broad frequency and angular band. This method hybridizes the cubic spline interpolation method and the Steor-Bulirsch model. The cubic spline interpolation method is applied to model the induced current over wide angular band, while the Steor-Bulirsch model is applied to accelerate calculation over wide frequency band. Therefore, a great deal of time could be saved for the calculation of frequency- and angular-sweep. Numerical results demonstrate that this hybrid method is efficient for wide-band scattering calculation of precipitation particles with high accuracy.