Improved direct radiation pattern estimation in FDTD

Application of direct radiation pattern estimation in finite difference time domain (FDTD) simulation environment as an alternative to cumbersome near-to-far field transformation is considered. With the proposed improvement, direct estimation of the radiation pattern from the field strength samples in FDTD method becomes significantly less sensitive to the antenna geometry and thus more applicable to practically relevant cases. The main idea is to use field samples taken at two different radii to account for antenna geometry. The samples are taken at radii that are as close as possible to the antenna but still not too close to spoil the correctness of the results. The introduced improvement, combined with multigrid simulation domain and higher order accuracy FDTD formulations, reduces the necessary size of the computational domain, which directly leads to reduced memory consumption and a smaller error due to numerical dispersion.