Abstract:In this paper, a terahertz slotted waveguide array antenna is designed based on photonic crystal, which can realize effi-cient radiation of terahertz waves. The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna, coupled to photonic crystal waveguide through photonic crystal cavity, and radiated outward through slots at the top layer of antenna. The simulation results show that the antenna achieves a peak gain of 13.45dBi at 360 GHz, a half-power beamwidth of 10.9o, and a side lobe level of ?13.9dB. The antenna based on photonic crystal has the ad-vantages of low profile, low loss, and high radiation efficiency, which can be applied to terahertz wireless communication systems.