The antenna in the embodiments provided includes: a first-layer antenna, a second-layer antenna, a first probe, a second probe, a first connector, and a second connector. An annular microstrip patch is attached to each of main bodies of the first-layer antenna and the second-layer antenna. The annular microstrip patch attached to the first-layer antenna is provided with a first feeding network and a second feeding network therein. The first-layer antenna is connected to the first probe and the second probe by using the first feeding network and the second feeding network respectively. The first-layer antenna is connected to the first connector and the second connector. A position of the first connector corresponds to a position where the first probe is connected to the first-layer antenna. A position of the second connector corresponds to a position where the second probe is connected to the first-layer antenna.