▎ 摘　　要

In this letter, a novel 3D multi-beam reconfigurable THz loop antenna capable of steering its main beam in the semi-sphere space (theta epsilon {0 degrees, +/- 5 degrees, +/- 10 degrees}; phi epsilon {0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees}) is presented. The antenna is based on a switchable circular high impedance surface (HIS) using the graphene-metal hybrid approach. The effect of gate voltage on the conductivity of graphene and the switchable reflection characteristic of the graphene-based HIS are combined in the design. Changing the chemical potential of different graphene-based HIS units can effectively adjust the beam direction. The performance of the antenna is analyzed through its reflection coefficients and gain radiation patterns, and simulated results show that the maximum gain can reach 3.23 dBi at 0.5 THz.