Reconfigurable Antenna and Communications Device

Abstract

A reconfigurable antenna includes a first antenna and a second antenna. The first antenna is an omnidirectional antenna, and the second antenna surrounds the first antenna. The second antenna includes a plurality of antenna element groups. Each antenna element group includes a transmission cable, a switch, a first antenna element, and a second antenna element. The transmission cable is connected to the first antenna element and the second antenna element. The transmission cable is connected to a feedpoint. The switch is connected to a first point and a second point on the transmission cable. A sum of a length of antennas and transmission cables in an antenna element group is slightly greater than ½ wavelength (λ.sub.1), where λ.sub.1 is a wavelength of an electromagnetic wave on an operating frequency of the first antenna.

Claims

1. A reconfigurable antenna, comprising: a first antenna, wherein the first antenna is an omnidirectional antenna; and a second antenna that surrounds the first antenna, wherein the second antenna comprises a plurality of antenna element groups, and wherein each antenna element group in the antenna element groups comprises: a transmission cable comprising a first end and a second end; a switch, wherein the switch is coupled to a first point on the transmission cable and to a second point on the transmission cable; and two antenna elements coupled to the transmission cable, wherein the two antenna elements comprise a first antenna element and a second antenna element, wherein the first end is connected to the first antenna element, wherein the second end is connected to the second antenna element, wherein a sum of a length from a third end of the first antenna element to a connection point between the first antenna element and the first end, a length from the first end to the first point, a length from the second end to the second point, and a length from a fourth end of the second antenna element to a connection point between the second antenna element and the second end slightly greater than ½π.sub.1, and wherein λ.sub.1 is a wavelength of an electromagnetic wave on an operating frequency of the first antenna.

2. The reconfigurable antenna of claim 1, wherein a sum of lengths of the two antenna elements is 0.5λ.sub.2-1.2λ.sub.2, and wherein λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of the second antenna.

3. The reconfigurable antenna of claim 1, wherein a distance between the first antenna and each of the first antenna element and the second antenna element is 0.2λ.sub.1-0.3λ.sub.1.

4. The reconfigurable antenna of claim 1, further comprising a feedpoint coupled to the transmission cable, wherein the feedpoint is connected to any position on the transmission cable, and wherein a distance between the feedpoint to the first end is the same as a distance between the feedpoint to the second end.

5. The reconfigurable antenna of claim 1, wherein a shape of each antenna element group is an arc, and wherein elements in each of the antenna element groups surround the first antenna to form a circle.

6. The reconfigurable antenna of claim 1, wherein a distance between a center of the reconfigurable antenna to each of the first antenna element and the second antenna element is 0.5λ.sub.2-0.7λ.sub.2, and wherein λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of the second antenna.

7. The reconfigurable antenna of claim 1, wherein the antenna element groups comprise four antenna element groups.

8. The reconfigurable antenna of claim 1, further comprising a substrate, wherein the first antenna and the second antenna are disposed on the substrate.

9. The reconfigurable antenna of claim 1, wherein a shape of the first antenna is a circle.

10. A communications device, comprising: a radio frequency circuit; and a reconfigurable antenna coupled to the radio frequency circuit, wherein the reconfigurable antenna comprises: a first antenna, wherein the first antenna is an omnidirectional antenna; and a second antenna that surrounds the first antenna, wherein the second antenna comprises a plurality of antenna element groups, and wherein each antenna element group in the antenna element groups comprises: a transmission cable comprising a first end and a second end; a switch, wherein the switch is coupled to a point on the transmission cable and to a second point on the transmission cable; and two antenna elements coupled to the transmission cable, wherein the two antenna elements comprise a first antenna element and a second antenna element, wherein the first end is connected to the first antenna element, wherein the second end is connected to the second antenna element, wherein a sum of a length from a third end of the first antenna element to a connection point between the first antenna element and the first end, a length from the first end to the first point, a length from the second end to the second point, and a length from a fourth end of the second antenna element to a connection point between the second antenna element and the second end is slightly greater than 1/2λ.sub.1, and.

11. The communication device of claim 10, wherein a sum of lengths of the two antenna elements is 0.5λ.sub.2-1.2λ.sub.2, and wherein λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of the second antenna.

12. The communication device of claim 10, wherein a distance between the first antenna and each of the first antenna element and the second antenna element is 0.2λ.sub.1-0.3λ.sub.1.

13. The communication device of claim 10, further comprising a feedpoint coupled to the transmission cable, wherein the feedpoint is connected to any position on the transmission cable, and wherein a distance between the feedpoint to the first end is the same as a distance between the feedpoint to the second end.

14. The communication device of claim 10, wherein a shape of each antenna element group is an arc, and wherein elements in each of the antenna element groups surround the first antenna to form a circle.

15. The communication device of claim 10, wherein a distance between a center of the reconfigurable antenna to each of the first antenna element and the second antenna element is 0.5λ.sub.2-0.7λ.sub.2, and wherein λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of the second antenna.

16. The communication device of claim 10, comprising four antenna element groups.

17. The communication device of claim 10, further comprising a substrate, wherein the first antenna and the second antenna are disposed on the substrate.

18. The communication device of claim 10, wherein a shape of the first antenna is a circle.

19. An antenna, comprising: a plurality of antenna element groups, wherein each antenna element group in the antenna element groups comprises: a transmission cable comprising a first end and a second end; a switch, wherein the switch is coupled to a first point on the transmission cable and to a second point on the transmission cable; and two antenna elements coupled to the transmission cable, wherein the two antenna elements comprise a first antenna element and a second antenna element, wherein the first end is connected to the first antenna element, wherein the second end is connected to the second antenna element, wherein a sum of a length from a third end of the first antenna element to a connection point between the first antenna element and the first end, a length from the first end to the first point, a length from the second end to the second point, and a length from a fourth end of the second antenna element to a connection point between the second antenna element and the second end of the transmission cable is slightly greater than ½λ.sub.1, and wherein λ.sub.1 is a wavelength of an electromagnetic wave of an operating frequency received at the antenna.

20. The antenna of claim 19, wherein a sum of lengths of the two antenna elements is 0.5λ.sub.2-1.2λ.sub.2, and wherein λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of the antenna.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a radiation range diagram of a reconfigurable antenna in three modes according to an embodiment of this application;

[0022] FIG. 2 is a schematic structural diagram of a reconfigurable antenna according to an embodiment of this application;

[0023] FIG. 3 is a schematic structural diagram of an antenna element group in a reconfigurable antenna according to an embodiment of this application;

[0024] FIG. 4 is a schematic structural diagram of a second antenna in a reconfigurable antenna according to an embodiment of this application;

[0025] FIG. 5 is a schematic structural diagram of a first antenna in a reconfigurable antenna according to an embodiment of this application; and

[0026] FIG. 6 is another schematic structural diagram of a reconfigurable antenna according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

[0027] To make objectives, technical solutions, and advantages of this application clearer, the following further describes this application with reference to the accompanying drawings.

[0028] Reference signs: 10: first antenna; 100: first antenna element group; 110: third antenna element; 120: first transmission cable; 130: first feedpoint; 20: second antenna; 200: antenna element group; 210: first antenna element; 220: transmission cable; 230: feedpoint; 240: switch; 250: second antenna element; and 30: substrate.

[0029] To facilitate understanding of a reconfigurable antenna in this application, a principle of the antenna is described. A Yagi antenna is used as an example. The Yagi antenna includes three pairs of antenna elements, the three pairs of antenna elements are disposed in parallel, and the three pairs of antenna elements are all disposed on a metal beam. An antenna element connected to a feeder is referred to as an active antenna element or a main antenna element that is located in the middle of the three pairs of antenna elements. An antenna element slightly longer than the active antenna element is referred to as a reflector. The reflector is on one side of the active antenna element, and is used to weaken an electromagnetic wave transmitted from the direction of the reflector or an electromagnetic wave transmitted from this antenna to the reflector.

[0030] The main antenna element is equal to a half wavelength, the reflector is slightly longer than the half wavelength, and two antenna elements are spaced by a quarter wavelength. In this case, a director is “capacitive” to an induction signal whose current is advanced by 90 degrees (°) relative to a voltage. An electromagnetic wave induced by the director is radiated to the main antenna element. A radiation signal is lagged by 90° after passing through a quarter-wavelength path. This exactly cancels out the “advance” caused above. Phases of electromagnetic fields of the director and the main antenna element are the same. Therefore, signals are superimposed for enhancement. The reflector is slightly longer than the half wavelength and has inductive reactance, where a current is lagged by 90°. In addition, there is another 90° lag in a process of radiation to the main antenna element. They are added to obtain 180°. This has a cancellation function. Enhancement is performed in a direction, and weakening is performed in another direction such that superdirectivity is obtained. A function and a process in a transmit state are similar.

[0031] Generally, the reconfigurable antenna can radiate an omnidirectional beam, a high-density beam, and a directional beam. When the reconfigurable antenna presents 360° uniform radiation on a horizontal plane, and an included angle between a maximum radiation direction on a pitch plane and a downward direction perpendicular to the antenna is 70° to 80°, the reconfigurable antenna radiates the omnidirectional beam. When the included angle between the maximum radiation direction on the pitch plane of the reconfigurable antenna and the downward direction perpendicular to the antenna is decreased to enable beams to be concentrated in a relatively small coverage area, the reconfigurable antenna radiates the high-density beam. The high-density beam may reduce an overlapping area between two adjacent Wi-Fi devices to reduce interference and noise. When the reconfigurable antenna no longer presents 360° uniform radiation on the horizontal plane, but presents directivity, the reconfigurable antenna radiates the directional beam. Referring to FIG. 1. An area A is a signal radiation area existing when the reconfigurable antenna is in an omnidirectional mode, an area B is a signal radiation area existing when the reconfigurable antenna is in a high-density mode, and an area C is a signal radiation area existing when the reconfigurable antenna is in a directional mode. However, a current reconfigurable antenna can radiate only one or two of the omnidirectional beam, the directional beam, and the high-density beam. In addition, when the reconfigurable antenna can be switched between the omnidirectional mode and the directional mode, a structure of the reconfigurable antenna is complex, and a quantity of reconfigurable antennas and space occupied by the antenna are increased.

[0032] Therefore, this application provides a reconfigurable antenna that can be switched among the omnidirectional mode, the directional mode, and the high-density mode to respectively radiate the omnidirectional beam, the directional beam, and the high-density beam.

[0033] To make the objectives, technical solutions, and advantages of this application clearer, with reference to accompanying drawings and specific embodiments, the following further describes the reconfigurable antenna provided in this application.

[0034] Terms used in the following embodiments are merely intended to describe specific embodiments, but are not intended to limit this application. The terms “one”, “a”, “the”, “the foregoing”, “this”, and “the one” of singular forms used in this specification and the appended claims of this application are also intended to include plural forms such as “one or more”, unless otherwise specified in the context clearly.

[0035] Reference to “an embodiment”, “some embodiments”, or the like described in this specification indicates that one or more embodiments of this application include a specific feature, structure, or characteristic described with reference to the embodiments. Therefore, in this specification, statements, such as “in an embodiment”, “in some embodiments”, “in some other embodiments”, and “in other embodiments”, that appear at different places do not necessarily mean referring to a same embodiment, instead, they mean “one or more but not all of the embodiments”, unless otherwise emphasized in other ways. The terms “include”, “comprise”, “have”, and variants of the terms all mean “include but are not limited to”, unless otherwise emphasized in other ways.

[0036] In the embodiments provided in this application, the reconfigurable antenna has three modes: the omnidirectional mode, the directional mode, and the high-density mode such that the reconfigurable antenna can be switched among the omnidirectional mode, the directional mode, and the high-density mode based on an application scenario of the reconfigurable antenna. This reduces a quantity of antennas and a space usage of the antenna.

[0037] First, λ.sub.1 and λ.sub.2 are described, where λ.sub.1 is a wavelength of an electromagnetic wave on an operating frequency of a first antenna, and λ.sub.2 is a wavelength of an electromagnetic wave on an operating frequency of a second antenna.

[0038] Further, in FIG. 2, the reconfigurable antenna may include a first antenna 10 and a second antenna 20. The first antenna 10 is an omnidirectional antenna, and the second antenna 20 surrounds the first antenna. To enable the reconfigurable antenna to be switched among the omnidirectional mode, the directional mode, and the high-density mode, the second antenna may further include a plurality of antenna element groups 200. Each antenna element group 200 may include a transmission cable 220, a switch 240, and two antenna elements. The two antenna elements may be respectively a first antenna element 210 and a second antenna element 250. A first end 221 of the transmission cable 220 is connected to the first antenna element 210, a second end 222 of the transmission cable 220 is connected to the second antenna element 250, and the transmission cable is connected to a feedpoint 230. In addition, a first point 260 and a second point 270 that are used to connect to the switch 240 are disposed on the transmission cable 220, and a sum (shown by a dash line in FIG. 2) of a length from an end 211 of the first antenna element 210 to a connection point between the first antenna element 210 and the first end 221 of the transmission cable 220, a length from the first end 221 of the transmission cable 220 to the first point 260 on the transmission cable 220, a length from the second end 222 of the transmission cable 220 to the second point 270 on the transmission cable 220, and a length from an end 251 of the second antenna element 250 to a connection point between the second antenna element 250 and the second end 222 of the transmission cable 220 (indicated by the dashed line in the FIG. 2) is slightly greater than ½λ.sub.1. When the first antenna 10 (the omnidirectional antenna) operates, no energy is fed to the plurality of feedpoints 230 in the plurality of antenna element groups 200, and the plurality of switches 240 are all turned off, the reconfigurable antenna is in the omnidirectional mode. When the first antenna 10 (the omnidirectional antenna) operates, a switch 240 in at least one antenna element group 200 in the plurality of antenna element groups 200 is turned on, at least one switch 240 in the plurality of antenna element groups 200 is turned off, and no energy is fed to the feedpoints 230 in the plurality of antenna element groups 200, a first antenna element 210 and a second antenna element 250 in the antenna element group 200 whose switch 240 is turned on may be used as a reflector to reflect an electromagnetic wave radiated by the first antenna 10 to the reflector such that the reconfigurable antenna is in the directional mode. When the first antenna 10 (the omnidirectional antenna) does not operate, energy is fed to the feedpoint 230 in each antenna element group 200 in the plurality of antenna element groups 200, and the switch 240 in each antenna element group 200 is turned off, an included angle between a beam radiated by the second antenna 20 and a horizontal plane is increased, and a beam coverage area is decreased such that the reconfigurable antenna is in the high-density mode.

[0039] It should be noted that both the first antenna 10 and the second antenna 20 may be integrated on a substrate 30.

[0040] Still referring to FIG. 2, when the second antenna 20 is further disposed, a sum of lengths of the first antenna element 210 and the second antenna element 250 in each antenna element group 200 is L1. A spacing between the first antenna and each of the first antenna element 210 and the second antenna element 250 in each antenna element group 200 is D1. A distance between a center of the first antenna and each of the first antenna element 210 and the second antenna element 250 in each antenna element group 200 is R1. Further, L1 is 0.5λ.sub.2-1.2λ.sub.2. Therefore, in the reconfigurable antenna, when the first antenna 10 does not operate, energy is fed to the feedpoints 230 in the second antenna 20, and the switches 240 in the second antenna 20 are all turned off, the reconfigurable antenna is in the high-density mode, and the reconfigurable antenna can radiate an electromagnetic wave within a preset area. D1 is 0.2-0.3λ.sub.1, and R1 is 0.5λ.sub.2-0.7λ.sub.2 such that the second antenna 20 in the reconfigurable antenna can be used as a reflector or a structure in the high-density mode.

[0041] Still referring to FIG. 2, in each antenna element group 200, to ensure that paths on which energy fed to the feedpoint 230 connected to the transmission cable 220 is transmitted to the first antenna element 210 and the second antenna element 250 are the same, the transmission cable 220 may be further configured in a plurality of forms. For example, the transmission cable 220 may include a first conductor and a second conductor. The first conductor and the second conductor each have a first end and a second end, the first end of the first conductor is connected to the first antenna element 210, the first end of the second conductor is connected to the second antenna element 250, and the second end of the first conductor and the second end of the second conductor are connected to each other. The first conductor and the second conductor may be symmetrically distributed whereby a part of the first conductor and a part of the second conductor may be parallel to each other, and another part of the first conductor and another part of the second conductor may be bent. Alternatively, in FIG. 3, the transmission cable 220 includes two conductors respectively connected to the first antenna element and the second antenna element. Ends, of the two conductors, away from the first antenna element and the second antenna element are connected to each other (that is, the two conductors are disposed in a V shape).

[0042] It should be noted that the transmission cable 220 may have another type of form. Forms of the first conductor and the second conductor that are included in the transmission cable 220 may be different, and the first conductor and the second conductor may be curves that are symmetrically disposed, provided that the transmission cable 220 can implement sufficient impedance matching.

[0043] In an embodiment, there may be two, three, four, five, or six antenna element groups 200. Further, in FIG. 4, when there are four antenna element groups 200, the four antenna element groups 200 are disposed in a circular shape (that is, antenna elements are disposed in an arc shape). In this case, the first antenna disposed in an inner circumference of the plurality of antenna element groups 200 may also be disposed in a circular shape.

[0044] With reference to FIG. 2 and FIG. 4, in a clockwise direction, four switches 240 (a, b, c, and d) and four feedpoints 230 (1, 2, 3, and 4) are respectively disposed in the four antenna element groups 200 included in the second antenna 20. When the reconfigurable antenna is in the omnidirectional mode, the first antenna 10 operates, the four switches 240 (a, b, c, and d) in the second antenna 20 are all turned off, and no energy is fed to the four feedpoints 230 (1, 2, 3, and 4) in the second antenna 20. When the reconfigurable antenna is in the directional mode, the first antenna 10 operates, and no energy is fed to the four feedpoints 230 (1, 2, 3, and 4) in the second antenna 20. In the four switches 240 (a, b, c, and d), any switch 240 in a, b, c, and d may be turned on, and the other three switches 240 are turned off. In this case, an antenna element group 200 whose switch 240 is turned on is used as a reflector such that a signal of the reconfigurable antenna is radiated in directions of antenna element groups 200 provided with the three turned off switches 240. Alternatively, in the four switches 240 (a, b, c, and d), only one switch 240 is turned off, and the other three switches 240 are turned on. In this case, antenna element groups 200 whose switches 240 are turned on are used as reflectors such that a signal of the reconfigurable antenna is radiated in a direction of an antenna element group 200 provided with the turned off switch. Alternatively, in the four switches (a, b, c, and d), any two switches 240 in a, b, c, and d may be turned on, and the other two switches 240 are turned off. In this case, antenna element groups 200 whose switches 240 are turned on are used as reflectors such that a signal of the reconfigurable antenna is radiated in directions of antenna element groups 200 provided with the two turned off switches 240. When the reconfigurable antenna is in the high-density mode, the first antenna 10 does not operate, energy is fed to all the four feedpoints 230 (1, 2, 3, and 4) in the second antenna 20, and the switch 240 in each antenna element group 200 is turned off.

[0045] The switch 240 may be a diode.

[0046] It should be noted that, to adjust a size obtained after the first antenna element and the second antenna element in each antenna element group are connected and a size of the reflector as which the first antenna element and the second antenna element are used, both the switch and the feedpoint that are located on the transmission cable may be adjusted relative to a position of the transmission cable during assembly, the feedpoint is disposed between the switch and the second antenna element, and the switch and the feedpoint do not overlap.

[0047] Referring to FIG. 5. In the foregoing solution, the first antenna is configured as an omnidirectional antenna. Further, the first antenna may include a plurality of first antenna element groups 100, the first antenna element group 100 may include a first transmission cable 120 and two third antenna elements 110, and the first transmission cable 120 is configured to connect the two third antenna elements 110. A first feedpoint 130 is disposed on the first transmission cable 120, and paths on which energy is transmitted from the first feedpoint 130 to the two third antenna elements 110 are the same. When the first antenna 10 operates, energy is simultaneously fed to the first feedpoints 130 in the first antenna element groups 100.

[0048] In a solution, there may be three, four, five, or six first antenna element groups 100. When three first antenna element groups 100 are configured, the three first antenna element groups 100 may be disposed in a circular shape, and the three first antenna element groups 100 may further be rotationally symmetric with respect to a center of a circle. In this case, the third antenna element 110 in each first antenna element group 100 may be disposed in an arc shape. When four first antenna element groups 100 are configured, the four first antenna element groups 100 may be disposed in a circular, rectangular, or rhombic shape. In this case, the third antenna element in each first antenna element group may be disposed in a linear shape.

[0049] It should be noted that when three first antenna element groups are disposed, three antenna element groups may be disposed, and the antenna element groups are distributed in a one-to-one correspondence with the first antenna element groups in a radial direction of the substrate. Alternatively, when three first antenna element groups are disposed, four antenna element groups may be disposed. Quantity configuration requirements of the first antenna element group and the antenna element group are not limited, provided that the reconfigurable antenna can be switched among the omnidirectional mode, the directional mode, and the high-density mode.

[0050] Still referring to FIG. 5, in a solution, to enable the first antenna to be disposed on the substrate more conveniently, ends that are of two first transmission cables 120 in two adjacent first antenna element groups 100 and that are away from the third antenna element 110 may be connected to each other, that is, the two first transmission cables 120 in the two adjacent first antenna element groups 100 are short-circuited.

[0051] Still referring to FIG. 5, the first antenna is an omnidirectional antenna to ensure that paths on which energy fed to the first feedpoint 130 in each first antenna element group 100 moves to the two third antenna elements 110 in the first antenna element group 100 are the same. The first transmission cable 120 may have a plurality of specific structural forms. For example, the first transmission cable 120 includes two third conductors, and the two third conductors each have a first end and a second end. The first ends of the two third conductors are respectively connected to the two third antenna elements 110. When the two third conductors are disposed in parallel, the first transmission cable 120 further includes a first connection line, and the first connection line connects the second ends of the two third conductors. The first feedpoint 130 is disposed between the two parallel third conductors, and lengths of third conductors between the third antenna elements 110 and connection points between the first feedpoint 130 and the two third conductors are the same. Alternatively, when the two third conductors are disposed in a V shape (not shown in the figure), the first ends of the two third conductors are respectively connected to the two third antenna elements 110, and the second ends of the two third conductors may be connected to each other. The first feedpoint is disposed between the two third conductors, and lengths of third conductors between the third antenna elements 110 and connection points between the first feedpoint 130 and the two third conductors are the same.

[0052] It should be noted that a position of the first feedpoint on the first transmission cable is adjustable to adjust signal radiation strength of the first antenna.

[0053] Still referring to FIG. 5, when the first antenna is further disposed, a sum of lengths of the two third antenna elements 110 in each first antenna element group 100 is L2, a distance between the third antenna element 110 in each first antenna element group 100 and the center of the first antenna is R2, and a length from an end that is of the first transmission cable and that is connected to the third antenna element 110 to an end away from the third antenna element 110 is D2. Further, to ensure that the first antenna is an omnidirectional antenna during operating, L2 is 0.5-1λ.sub.1, D2 is 0.2-0.3λ.sub.1, and R2 is 0.2-0.4λ.sub.1. Further, a size of each part of the first antenna meets a specified range to ensure that the first antenna can radiate an omnidirectional electromagnetic wave.

[0054] With reference to FIG. 2 and FIG. 5, there are four first antenna element groups 100, and the four first antenna element groups 100 are disposed in an annular shape. There are also four antenna element groups 200, and the four antenna element groups 200 are disposed in a circular shape. In the clockwise direction, four first feedpoints 130 (5, 6, 7, and 8) are respectively disposed in the four first antenna element groups 100 included in the first antenna 10. When the reconfigurable antenna is in the omnidirectional mode and the directional mode, energy is simultaneously fed to the four first feedpoints 130 (5, 6, 7, and 8) in the first antenna 10.

[0055] Referring to FIG. 6, the first antenna includes three first antenna element groups 100, the second antenna includes six antenna element groups 200, the three first antenna element groups 100 are disposed in a circular shape, the six antenna element groups 200 are also disposed in a circular shape, and the three first antenna element groups 100 correspond to three of the six antenna element groups 200. When energy is simultaneously fed to three first feedpoints 130 disposed in the three first antenna element groups 100, no energy is fed to six feedpoints 230 in the six antenna element groups 200, and six switches 240 in the six antenna element groups 200 are all turned off, the reconfigurable antenna is in the omnidirectional mode. When energy is simultaneously fed to the three first feedpoints 130 disposed in the three first antenna element groups 100, and no energy is fed to the six feedpoints 230 in the six antenna element groups 200, one switch 240 in the six switches 240 in the six antenna element groups 200 may be turned on, or two switches 240 in the six switches 240 may be turned on. Three switches 240 in the six antenna element groups 200 may be turned on, a maximum of five switches 240 in the six switches 240 may be turned on, and at least one switch 240 in the six switches 240 needs to be turned off. In this way, a beam is radiated in a direction of an antenna element group 200 whose switch 240 is turned off such that the reconfigurable antenna is in the directional mode. When no energy is fed to the three first feedpoints 130 disposed in the three first antenna element groups 100, energy is simultaneously fed to the six feedpoints 230 in the six antenna element groups 200, and the six switches 240 in the six antenna element groups 200 are all turned off, the reconfigurable antenna is in the high-density mode.

[0056] This application further provides a communications device, where the communications device has the reconfigurable antenna in any one of the foregoing technical solutions. The communications device may be further configured as a base station or a Wi-Fi device.

[0057] The foregoing descriptions are merely implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.