Study of High-Power Wideband Terahertz-Pulse Generation Using Integrated High-Speed Photoconductive Semiconductor Switches

A 3-D finite-difference time-domain analysis of a photoconductive-semiconductor-switch-based terahertz (THz) source, integrated with a standard dipole and a large-aperture radiator, is presented. The simulation analysis is based on the coupling of semiconductor equations for charge transport with Maxwell electromagnetic equations. The simulation provides the transient field redistribution, carrier generation characteristics, and the field acceleration as a result of the bias voltage on the device, contributing to the nonlinear behavior of THz-pulse generation. A comparison of the radiation characteristics of the two antenna types shows that the large-aperture antenna produces approximately three times higher radiation amplitude and broader power spectrum than those produced by the dipole antenna.