Simulation of radiation characteristics of 34 μm aperture GaAs dipole photoconductive antenna

Simulation characteristics of photoconductive antenna(PCA) radiation are the important basis for design and manufacture of photoconductive antenna. The method introduced the relationship between Monte-Carlo empirical-formula and updated GaAs migration-rate versus electric-field strength. The photo-generated carrier-density of 34 m-apeture GaAs dipole photoconductive antenna was computed based on Drude-Lorentz model. Combining the photo-generated carrier-density with finite difference time domain(FDTD) method, time-domain, frequency-domain and three-dimensional radiation characteristics were simulated. The frequency spectrum of the terahertz radiation ranged about 1 THz, and its amplitude peaks were at roughly 0.8 THz, which consisted well with the data obtained from terahertz time-domain spectrum system(THz-TDS). The results show the feasibility of this method, which provides a reference for design and manufacture of the high-gain, wideband THz photoconductive antenna.