An antenna, comprising: a plurality of antenna units, wherein each antenna unit comprises a plurality of antenna branches and one feed branch; the plurality of antenna branches are all connected to the feed branch; and different antenna branches in a same antenna unit correspond to different frequency bands; at least one antenna unit pair exists in the plurality of antenna units, wherein a first antenna unit of the pair has a branch supporting a frequency band that is the same as the frequency supported by a branch of a second antenna unit of said pair, a distance between two antenna units in each antenna unit pair is less than a first preset distance, and radiation directions of antenna branches in each antenna unit pair that correspond to a same frequency band are different; a substrate, wherein the substrate has a first surface; and the plurality of antenna units are located at edge positions of the first surface; and a ground plate, wherein the substrate further has a second surface; the second surface is parallel to the first surface; and the ground plate is located on the second surface, wherein one end of the feed branch has a feed point, and another end has a ground point; and ground points of all the antenna units are connected to the ground plate, wherein the ground plate has a clearance area of each antenna unit; and the clearance area of each antenna unit is located in a projection area of the antenna unit on the ground plate, and wherein the plurality of antennas further comprises two neighboring antenna units, wherein a distance between the ground points of the two neighboring antenna units in the plurality of antenna units is less than or equal to λ /12, the ground plate further has a clearance area corresponding to a separation area between the two neighboring antenna units, wherein the clearance area corresponding to the separation area is a projection area of the separation area on the ground plate. a plurality of antenna units, wherein each antenna unit comprises a plurality of antenna branches and one feed branch; the plurality of antenna branches are all connected to the feed branch; and different antenna branches in a same antenna unit correspond to different frequency bands; at least one antenna unit pair exists in the plurality of antenna units, wherein a first antenna unit of the pair has a branch supporting a frequency band that is the same as the frequency supported by a branch of a second antenna unit of said pair, a distance between two antenna units in each antenna unit pair is less than a first preset distance, and radiation directions of antenna branches in each antenna unit pair that correspond to a same frequency band are different; a substrate, wherein the substrate has a first surface; and the plurality of antenna units are located at edge positions of the first surface; and a ground plate, wherein the substrate further has a second surface; the second surface is parallel to the first surface; and the ground plate is located on the second surface, wherein one end of the feed branch has a feed point, and another end has a ground point; and ground points of all the antenna units are connected to the ground plate, wherein the ground plate has a clearance area of each antenna unit; and the clearance area of each antenna unit is located in a projection area of the antenna unit on the ground plate, and wherein the plurality of antennas further comprises two neighboring antenna units, wherein a distance between the ground points of the two neighboring antenna units in the plurality of antenna units is less than or equal to λ /12, the ground plate further has a clearance area corresponding to a separation area between the two neighboring antenna units, wherein the clearance area corresponding to the separation area is a projection area of the separation area on the ground plate.