Study On THz Generation From Large Area Photoconductive Antenna

Terahertz signals were until recently an almost unexplored area of research due to the difficulties in generation and detection of electromagnetic fields at these wavelengths. Neither optical nor microwave techniques are directly applicable in the terahertz range since optical wavelengths are too short and microwave wavelengths are too long compared to terahertz field wavelengths. The development of ultrafast optical techniques, the manufacturing of semi-insulating semiconductors with very short lifetimes and of band-engineered heterostructures , as well as the micromachining techniques and nanotechnology has boosted the terahertz fields as a new area of research in quantum electronics with many important applications.The small dipole aperture antenna provides a normal way for THz radiation, for which the Drude-Lorentz theory provides method to calculate the Terahertz waves from photoconductor. For sake of this Drude-Lorentz theory is not suitable for large-aperture photoconductive antenna, in this paper, the calculation of terahertz radiation from biased photoconductive antenna (Drude-Lorentz theory) is reported, given a melioration of the calculation of carriers' density, which is more suitable for large aperture antenna. Several simulation results based on the new calculation model are shown and analysis of the effects of different factors to THz radiation based on these calculation results is shown, by which the new calculation model is proved more suitable for large aperture antenna.