A nonstandard higher order FDTD algorithm for 3-D arbitrarily and fractal-shaped antenna structures on general curvilinear lattices

A new higher order finite-difference time-domain (FDTD) methodology for the consistent modeling of arbitrarily shaped antennas in three-dimensional (3D) curvilinear coordinates is presented in this paper. The generalized algorithm, which introduces novel conventional and nonstandard regimes, develops advanced PMLs and compact differences to handle the widened spatial increments. Also, a systematic leapfrog integrator with mesh expansion concepts is established. Beyond diverse 3D structures, analysis studies fractal arrays whose self-similarity renders them ideal for small-sized designs. Results indicate that the proposed method achieves a critical elimination of lattice errors and provides very precise radiation patterns