Fig. 1. Principle diagram of terahertz pulse emitted by a photoconductive antenna

Fig. 2. Schematic diagram of the butterfly antenna structure

Fig. 3. Schematic of antenna beam radiation

Fig. 4. The simulated electric field distribution at 0.1 THz (the direction of the electric field follows the x-axis)

Fig. 5. The far-field simulation results of the butterfly antenna at 0.1 THz

Fig. 6. The radiation characteristics of the butterfly antenna at 0.8 THz and 1.5 THz frequencies