Characterization of near- and far-field radiation from ultrafast electronic systems

Accurate and computationally efficient chararterization of near- and far-fi eld radiation from a class of microwave, millimeter wave, and ultrafast sys tems is presented. A numerical technique is utilized which combines the fin ite-difference time-domain method with a spatial transformation, the Kirchh off surface integral. Included in the analysis are inhomogeneous material p arameters, small feature size relative to wavelengths of interest, and the wide-band nature of the radiation. Based on simulation results, a simple mo del of the radiation from an inhomogeneous structure is del eloped. Finally , the technique is applied to accurately characterize the radiation from a photoconducting structure.