Patent Application
20220158344
This application claims priority to Chinese Patent Application No. 202011277940.7, filed on Nov. 16, 2020, which is hereby incorporated by reference in its entirety.
This application relates to the field of antenna technologies, and in particular, to a reconfigurable antenna and a communications device.
With development of a wireless communications and information system, the communications system also imposes diversified requirements on antennas, for example, broadband, intelligence, integration, and cost-effectiveness. Therefore, antenna design technologies such as aperture sharing, reconfigurability, and beamforming have received much attention, and are of great research significance in antenna development.
Because the antenna has different application scenarios, different types of beams need to be radiated based on an antenna position and different population density. However, a current antenna can radiate only one or two types of beams, and a structure of an antenna that can radiate two types of beams is complex.
Therefore, an antenna with a radiation range that can be applied to different environments is urgently required.
This application provides a reconfigurable antenna that can be switched among an omnidirectional mode, a directional mode, and a high-density mode such that the reconfigurable antenna can respectively radiate an omnidirectional beam, a directional beam, and a high-density beam.
According to a first aspect, this application provides a reconfigurable antenna. The 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 in the plurality of antenna element groups includes a transmission cable, a switch, and two antenna elements. A first end of the transmission cable is connected to a first antenna element in the two antenna elements. A second end of the transmission cable is connected to a second antenna element in the two antenna elements. 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 from an end of the first antenna element to a connection point between the first antenna element and the first end of the transmission cable, a length from the first end of the transmission cable to the first point on the transmission cable, a length from the second end of the transmission cable to the second point on the transmission cable, and a length from an 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 ½λ1, and λ1 is a wavelength of an electromagnetic wave on an operating frequency of the first antenna.
The reconfigurable antenna in this application may be switched among an omnidirectional mode, a directional mode, and a high-density mode based on an application scenario such that the reconfigurable antenna can respectively radiate an omnidirectional beam, a directional beam, and a high-density beam. This reduces a quantity of antennas and a space usage of the antenna. Further, when the first antenna (the omnidirectional antenna) operates, no energy is fed to the feedpoint in each antenna element group in the second antenna, and the switch in each antenna element group is turned off, only the first antenna (the omnidirectional antenna) in the reconfigurable antenna operates such that the reconfigurable antenna can radiate an omnidirectional electromagnetic wave. When the first antenna (the omnidirectional antenna) operates, switches in some antenna element groups in the second antenna are turned off, and switches in some other antenna element groups are turned on, because in each of the antenna element groups whose switches are turned on, the sum of the length of the first antenna element, the length of the second antenna element, the length from the first point to the first end of the transmission cable, and the length from the second point to the second end of the transmission cable is slightly greater than ½λ1, the antenna element groups whose switches are turned on are used as reflectors to reflect an electromagnetic wave radiated by the first antenna in the directions of the antenna element groups such that the electromagnetic wave radiated by the first antenna is radiated in directions of the antenna element groups whose switches are not turned on in the second antenna. Therefore, the reconfigurable antenna can radiate an electromagnetic wave in a predetermined direction. In addition, the second antenna surrounds the first antenna, in other words, a diameter of the second antenna is greater than a diameter of the first antenna. When the first antenna (the omnidirectional antenna) does not operate, energy is fed to the feedpoint in each antenna element group in the second antenna, and the switch in each antenna element group is turned off, an included angle between a beam radiated by the second antenna and a horizontal plane is increased such that a beam coverage area is decreased. In this case, the reconfigurable antenna can radiate a high-density electromagnetic wave.
It should be noted that when a skilled person assembles the reconfigurable antenna, in each antenna element group, the transmission cable first connects two antenna elements, and then the feedpoint is connected to the transmission cable. When the feedpoint is connected, it is ensured that lengths of transmission paths from the feedpoint to the two antenna elements through the transmission cable are the same. In addition, positions of the feedpoints in the antenna element groups are the same.
In a possible implementation, a sum of lengths of the two antenna elements is 0.5-1.2λ2, and λ2 is a wavelength of an electromagnetic wave on an operating frequency of the second antenna. Therefore, an electromagnetic wave radiated by the reconfigurable antenna in the high-density mode falls within a preset range.
In a specific implementation process, to ensure that the second antenna in the reconfigurable antenna can implement a function of the reflector, a distance between the antenna element in the second antenna and the first antenna is 0.2-0.3λ1.
In a possible implementation, a shape of the antenna element in each antenna element group is an arc such that the plurality of antenna element groups surround the first antenna to form a circle. A distance between each antenna element and a center of the reconfigurable antenna is 0.5-0.74λ2.
In a specific solution, there may be two, three, four, or five antenna element groups. When there are two antenna element groups, the two antenna element groups may be symmetrically disposed on two sides of the first antenna. When there are four antenna element groups, the antenna element groups may be disposed in an annular shape in a circumference of the first antenna.
In a possible implementation, both the first antenna and the second antenna are integrated on a substrate.
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. Each first antenna element group includes two third antenna elements and a first transmission cable that connects the two third antenna elements, and a first feedpoint is connected to the first transmission cable. In each first antenna element group, distances between the first feedpoint and the two third antenna elements are the same. When the first antenna radiates an omnidirectional electromagnetic wave, energy is simultaneously fed to the first feedpoints in the first antenna element groups.
It should be noted that ends that are of two first transmission cables in two adjacent first antenna element groups and that are away from the third antenna element may be short-circuited such that the first antenna can be disposed on the substrate more conveniently.
When the plurality of first antenna element groups are further disposed, the plurality of antenna element groups may be rotationally symmetric or centrosymmetric with respect to a center of the substrate.
In a specific solution, three, four, or five first antenna element groups may be further configured. When there are four first antenna element groups, the four first antenna element groups may be disposed in a circular shape. In this case, the second antenna disposed in the circumference of the first antenna may be disposed in a circular shape.
When the first antenna is further disposed, to ensure that the first antenna is an omnidirectional antenna during operating, a length of the third antenna element in each first antenna element group is 0.5-1λ1, length of the first transmission cable is 0.2-0.3λ1, and a radius of the third antenna element is 0.2-0.4λ1, where λ1 is the wavelength of the electromagnetic wave on the operating working frequency of the first antenna.
According to a second aspect, 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.
To make objectives, technical solutions, and advantages of this application clearer, the following further describes this application with reference to the accompanying drawings.
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.
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.
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.
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
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.
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.
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.
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.
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.
First, λ1 and λ2 are described, where λ1 is a wavelength of an electromagnetic wave on an operating frequency of a first antenna, and λ2 is a wavelength of an electromagnetic wave on an operating frequency of a second antenna.
Further, in
It should be noted that both the first antenna 10 and the second antenna 20 may be integrated on a substrate 30.
Still referring to
Still referring to
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.
In an embodiment, there may be two, three, four, five, or six antenna element groups 200. Further, in
With reference to
The switch 240 may be a diode.
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.
Referring to
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.
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.
Still referring to
Still referring to
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.
Still referring to
With reference to
Referring to
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011277940.7 | Nov 2020 | CN | national |
