Antenna and communications device

1. An antenna, comprising:

a plurality of antenna units, each antenna unit comprising:

a plurality of antenna branches, and

one feed branch; the plurality of antenna branches are all connected to the one feed branch; and different antenna branches of the plurality of antenna branches in a same antenna unit correspond to different frequency bands;

a substrate including a first surface and a second surface;

a ground plate located on the second surface; and

at least one antenna unit pair exists in the plurality of antenna units, 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, wherein one end of the feed branch includes a feed point, and another end includes a ground point, and ground points of all the antenna units are connected to the ground plate.

2. The antenna according to claim 1 , wherein the plurality of antenna units are located at edge positions of the first surface.

3. The antenna according to claim 1 , wherein the ground plate includes 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.

4. The antenna according to claim 3 , wherein a projection direction of each antenna unit on the ground plate is used as a vertical direction, and a minimum horizontal distance between a boundary that is of the feed branch in each antenna unit and that is away from the antenna branch and a boundary of the clearance area of the antenna unit is 0; and a minimum horizontal distance between a boundary that is of the antenna branch in each antenna unit and that is close to the feed point and a boundary of the clearance area of the antenna unit is λ50, wherein λ, is a wavelength corresponding to a lowest frequency in a lowest frequency band corresponding to each antenna unit.

5. The antenna according to claim 4 , wherein if a distance between ground points of two neighboring antenna units in the plurality of antenna units is less than or equal to λ12, the ground plate further includes 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.

6. A communications device, comprising:

an antenna, comprising:

a substrate including a first surface and a second surface;

a ground plate located on the second surface; and

a plurality of antenna units, each antenna unit comprising:

a plurality of antenna branches, and

one feed branch; the plurality of antenna branches are all connected to the one feed branch; different antenna branches of the plurality of 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; 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, wherein one end of the feed branch includes a feed point, and another end includes a ground point, and ground points of all the antenna units are connected to the ground plate.

7. The communications device according to claim 6 , further comprising: a radio frequency processor and a baseband processor, wherein the baseband processor is connected to the feed branch by using the radio frequency processor;

the antenna is configured to: transmit a received radio signal to the radio frequency processor, or convert a signal transmitted by the radio frequency processor into an electromagnetic wave, and send the electromagnetic wave out;

the radio frequency processor is configured to: perform frequency selection, amplification, and down-conversion processing on the radio signal received by the antenna, convert the processed radio signal into an intermediate-frequency signal or a baseband signal, and send the intermediate-frequency signal or the baseband signal to the baseband processor; or is configured to: perform up-conversion and amplification on a baseband signal or an intermediate-frequency signal sent by the baseband processor, and send the amplified baseband signal or intermediate-frequency signal out by using the antenna; and

the baseband processor is configured to process the intermediate-frequency signal or the baseband signal sent by the radio frequency processor.

8. The communications device according to claim 6 , wherein the plurality of antenna units are located at edge positions of the first surface.

9. The communications device according to claim 6 , wherein the ground plate includes 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.

10. The communications device according to claim 9 , wherein a projection direction of each antenna unit on the ground plate is used as a vertical direction, and a minimum horizontal distance between a boundary that is of the feed branch in each antenna unit and that is away from the antenna branch and a boundary of the clearance area of the antenna unit is 0; and a minimum horizontal distance between a boundary that is of the antenna branch in each antenna unit and that is close to the feed point and a boundary of the clearance area of the antenna unit is λ50.

11. The communications device according to claim 10 , wherein if a distance between ground points of two neighboring antenna units in the plurality of antenna units is less than or equal to λ12, the ground plate further includes 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.