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 . <EOS>