Far field radiation in sub-picosecond systems

FDTD and Monte Carlo methods are combined to simulate the terahertz radiation fields from a coplanar photoconducting structure. Two techniques are considered for modeling the far field radiation. One uses Maxwell equations directly with an approximation made regarding the source term. As an improvement to the first technique, we propose the use of a near-to-far-field FDTD transformation with the use of equivalent surface current densities. Computational results showing the far field radiation are in agreement with published experimental results.