An antenna structure includes a patch antenna including two opposite edges, a microstrip line connected to the patch antenna, two first radiation assemblies respectively disposed on two sides of the patch antenna, two second radiation assemblies disposed under the two first radiation assemblies, a liquid crystal layer disposed between a first plane and a second plane, and a ground plane disposed under the two second radiation assemblies. The patch antenna, the microstrip line, and the two first radiation assemblies are located on the first plane, and each of the first radiation assemblies includes multiple separated first conductors. The two second radiation assemblies are located on the second plane, and each of the second radiation assemblies includes multiple separated second conductors. A projection of the two second radiation assemblies on the first plane, the two first radiation assemblies, and the two edges of the patch antenna collectively form two loops.