A new hybrid FDTD field-teleportation approach for modeling radiating/scattering structures

The essence of the technique, called Field Teleportation, is to invoke the principle of equivalent sources (Schelkunoff's currents) using FDTD's discrete definition of the curl to copy any field propagating in one FDTD domain to a finite region of another domain without distortion [1]. Here an approach to teleport a frequency domain field into FDTD domain has been successfully tested for realistic large object scattering problem. The teleported field is used in FDTD to illuminate a scattering object introduced into the test region and the time-domain scattered signal has been transformed back into the frequency domain as induced equivalent surface currents. Having these currents, calculation of the far-field scattering becomes a trivial procedure. For the case of an exact frequency-domain solution, the error introduced by field-teleportation for 5λ by Sλ by 2λ modeled space with PEC boundary is less than -110 dB and the phase error is less than 0.16 degree. For the case of field obtained by Uniform Theory of Diffraction (UTD) on condense grid, intrinsic error has not exceeded -60 dB in magnitude and ±3 degree in phase. In this case main error caused by H-field retrieving from E-field on condensed (non-Yee) grid. Our modeling shows high importance of the grid matching between any frequency domain method and FDTD (E and H-field components have to be found on Yee-grid for the best field teleportation).