The disclosure provides an antenna structure including a ground plane, a first coupling antenna and a reference antenna. The first coupling antenna includes a first excitation source connected to the ground plane. The first excitation source is configured to excite a first resonant mode, and the first coupling antenna forms a first zero current area on the ground plane in response to the first resonant mode. The reference antenna includes a second excitation source connected to the ground plane. The second excitation source is configured to excite a second resonant mode, and the reference antenna forms a second zero current area on the ground plane in response to the second resonant mode. The first excitation source is located in the second zero current area, and the second excitation source is located in the first zero current area.