Antenna

Abstract

An antenna, comprising a radiator. The radiator comprises a first metal layer and N feeding structures, the first metal layer being coupled to the N feeding structures; the first metal layer satisfies circular symmetry; the N feeding structures are in one-to-one correspondence with N ports, and each feeding structure is used for the corresponding port to transmit a signal to the radiator, where N is an integer greater than or equal to 3; the N feeding structures comprise one first feeding structure and M second feeding structures, where M is an integer less than N and greater than 1; the distance between the projection of the first feeding structure on the first metal layer and the geometric center of the first metal layer is less than or equal to a first threshold; the M second feeding structures surround the first feeding structure, and the arrangement of the M second feeding structures satisfies circular symmetry; and the N feeding structures form a circularly symmetrical structure. The antenna provided by the present application can improve spectral efficiency and reduce interference between multiple users within a limited antenna aperture.

Description

An antenna

[0001] The present application claims priority to the Chinese patent application No. 202410726248.X, filed on June 5, 2024, with the State Intellectual Property Office of China, the Chinese patent application No. 202410726248.X has the title of “An antenna”, and the entire content of the Chinese patent application No. 202410726248.X is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of wireless communication, in particular to an antenna. BACKGROUND

[0003] With the continuous development of communication technology, the requirement for the spectrum efficiency of the wireless communication system is also increasing. Through the multi-user multiple-input multiple-output (MU-MIMO) technology, using the time division, frequency division or orthogonal coding method, the spectrum efficiency can be improved.

[0004] In actual product forms, such as macro base stations or micro base stations, the size of the antenna is often limited. How to improve the spectrum efficiency and reduce the interference between multiple users in a limited antenna aperture is a problem to be solved. SUMMARY

[0005] The embodiments of the present application provide an antenna, the first metal layer and the feed structure both satisfy circular symmetry, which can improve the spectrum efficiency and reduce the interference between multiple users in a limited antenna aperture.

[0006] In a first aspect, an antenna is provided, comprising: a radiator, the radiator comprising a first metal layer and N feed structures, the first metal layer and the N feed structures being coupled; the first metal layer satisfies circular symmetry; the N feed structures correspond one-to-one to N ports, each feed structure is used for transmitting a signal to the radiator for the corresponding port, N is an integer greater than or equal to 3; the N feed structures comprise one first feed structure and M second feed structures, M is an integer less than N and greater than 1; the projection of the first feed structure on the first metal layer is less than or equal to a first threshold value from the geometric center of the first metal layer; the M second feed structures surround the first feed structure, and the arrangement of the M second feed structures satisfies circular symmetry, and the N feed structures form a circularly symmetric structure.

[0007] Based on the scheme provided in the embodiments of the present application, the radiator of the antenna includes a first metal layer satisfying circular symmetry and a feeding structure, and a second feeding structure surrounds the first feeding structure. On the one hand, the radiation patterns of different ports of the antenna can be orthogonal, so as to ensure the isolation degree between the ports, improve the spectrum efficiency, and reduce the signal interference between multiple users. On the other hand, the distance between the projections of the first metal layer and the feeding structure in the z-axis direction is less than or equal to a first threshold value. The value of the first threshold value can be as small as possible, so that the symmetry of the radiation of the antenna in space is better.

[0008] In some possible implementation manners, N satisfies N=5, and M satisfies M=4.

[0009] Based on the scheme provided in the embodiments of the present application, the antenna includes five ports, so that the port density of the antenna is improved, and the spectrum efficiency in a limited antenna aperture can be improved.

[0010] In some possible implementation manners, when the antenna is used for communication at an X GHz frequency, the first metal layer satisfies at least one of the following conditions: A≤C / (2X); and / or, B≤C / (2X); wherein A represents the length of the first metal layer along a first direction, B represents the length of the first metal layer along a second direction, the plane formed by the first direction and the second direction is parallel to the first metal layer, and C represents the speed of light.

[0011] Based on the scheme provided in the embodiments of the present application, by including multiple ports in the antenna in an antenna aperture less than or equal to half the free space wavelength multiplied by half the free space wavelength, the spectrum efficiency in a limited antenna aperture can be improved.

[0012] In some possible implementation manners, the antenna further includes: a dielectric substrate, part of the N feeding structures or all of the N feeding structures are located in the dielectric substrate; a second metal layer, the second metal layer satisfies circular symmetry, and the second metal layer and the N feeding structures are coupled and connected; and the dielectric substrate is located between the first metal layer and the second metal layer.

[0013] Based on the scheme provided in the embodiments of the present application, the dielectric substrate is included between the first metal layer and the second metal layer of the antenna. On the one hand, the dielectric constant of the dielectric substrate can be greater than that of air, so that the size of the antenna can be reduced. On the other hand, the dielectric substrate with a space entity can provide an attachment position for the first metal layer and / or the second metal layer, so that the relative position of the first metal layer and the second metal layer can be kept stable.

[0014] In some possible implementation manners, the antenna further includes M first ground structures, the M first ground structures are coupled to the first metal layer, and the M first ground structures are electrically connected to the second metal layer; and / or, the antenna further includes M second ground structures, the M second ground structures are coupled to the first metal layer, and the M second ground structures are electrically connected to the second metal layer.

[0015] Based on the scheme provided in the embodiments of the present application, by setting the ground structure of the antenna corresponding to the feed structure, on the one hand, the length of the current flowing in the loop in the limited antenna aperture meets the required half free space wavelength of the resonance condition, which is beneficial to realize the miniaturization of the antenna; on the other hand, by setting multiple ground structures for one feed structure, the miniaturization of the antenna can be better realized, and the isolation between the ports can be increased; and on the other hand, the ground structure can also meet the circular symmetry, which can further realize the symmetry of the antenna pattern.

[0016] In some possible implementation manners, the first metal layer includes a first annular gap, and the first annular gap is located around the projection of the first feed structure on the first metal layer; and / or, the first metal layer includes a second annular gap, and the second annular gap is located around the projection of the second feed structure on the first metal layer.

[0017] Based on the scheme provided in the embodiments of the present application, by the annular gap formed between the first metal layer and the feed structure, capacitive impedance can be generated, which can offset the inductive impedance generated by the feed structure, so that the impedance matching of the antenna can be improved.

[0018] In some possible implementation manners, the first metal layer includes a third annular gap, and the third annular gap is located around the projection of the first ground structure on the first metal layer.

[0019] Based on the scheme provided in the embodiments of the present application, by the annular gap formed between the first metal layer and the first ground structure, capacitive impedance can be generated, so that the impedance matching of the antenna can be further improved.

[0020] In some possible implementation manners, the antenna further includes N microstrip lines, and each microstrip line is used to transmit a signal to a corresponding feed structure.

[0021] For example, the projections of M microstrip lines in the N microstrip lines on the first metal layer meet circular symmetry, and the M microstrip lines are coupled to the M second feed structures.

[0022] Based on the scheme provided in the embodiments of the present application, by providing the signal of the excitation port through the microstrip line, the additional loss caused by the special feed network can be avoided, and the production process of the antenna can be simplified.

[0023] In some possible implementation manners, the second metal layer includes N first through holes, the N first through holes correspond to the N feed structures one by one, and a distance between a projection of each first through hole on the first metal layer and a geometric center of a projection of the feed structure corresponding to the first through hole on the first metal layer is less than or equal to a second threshold.

[0024] Based on the scheme provided in the embodiments of the present application, the distance between the projection of the through hole of the second metal layer and the corresponding feed structure in the z-axis direction is less than or equal to the second threshold, and the second threshold can be as small as possible, so that the symmetry of the radiation of the antenna in space is better.

[0025] In some possible implementation manners, the part of at least one of the N microstrip lines connected with the feed structure includes a convex part.

[0026] Based on the scheme provided in the embodiments of the present application, by arranging the impedance matching branch on the microstrip line, the bandwidth of the antenna can be improved.

[0027] In some possible implementation manners, when the antenna is used for communication at a frequency of 10 GHz, the distance between the first feed structure and the second feed structure is 5.1 mm.

[0028] In a second aspect, an antenna array is provided, including at least two antennas as described in the first aspect and any implementation manner of the first aspect, and a distance between the first feed structures of two adjacent antennas in the antenna array is less than or equal to C / (2X) when the antenna array is used for communication at a frequency of X GHz, where C represents the speed of light.

[0029] In a third aspect, a base station is provided, including an antenna as described in the first aspect and any implementation manner of the first aspect, and a radio frequency unit connected with the antenna.

[0030] In a fourth aspect, a system is provided, including the base station as described in the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0031] FIG. 1 is a schematic diagram of a communication system suitable for embodiments of the present application.

[0032] FIGS. 2 and 3 are schematic diagrams of a projection of a first metal layer in a z-axis direction according to embodiments of the present application.

[0033] FIG. 4 is a schematic diagram of another projection of a first metal layer in a z-axis direction according to embodiments of the present application.

[0034] FIG. 5 is a schematic diagram of a port position arrangement according to embodiments of the present application.

[0035] FIG. 6 is a schematic diagram of another projection of a first metal layer in a z-axis direction according to embodiments of the present application.

[0036] FIG. 7 is a schematic diagram of a projection of a z-axis direction of an antenna according to an embodiment of the present application.

[0037] FIG. 8 is a schematic diagram of a projection of a z-axis direction of another antenna according to an embodiment of the present application.

[0038] FIG. 9 is a radiation pattern of a port of the antenna shown in FIG. 7 and FIG. 5.

[0039] FIG. 10 is a schematic diagram of simulation results of a reflection coefficient, an isolation, and a total efficiency of the port of the antenna shown in FIG. 7 and FIG. 5.

[0040] FIG. 11 is a schematic diagram of a projection of a z-axis direction of a microstrip line according to an embodiment of the present application.

[0041] FIG. 12 is a schematic diagram of a projection of a z-axis direction of a second metal layer according to an embodiment of the present application.

[0042] FIG. 13 is a schematic diagram of test results of an antenna according to an embodiment of the present application.

[0043] FIG. 14 is a schematic diagram of test results of another antenna according to an embodiment of the present application.

[0044] FIG. 15 is a schematic diagram of an antenna array according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] Hereinafter, terms that can appear in embodiments of the present application are explained.

[0046] It should be understood that the term “and / or” used herein is only a description of the same field of associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character “ / ” herein generally represents that the front and rear associated objects are in an “or” relationship.

[0047] “Within” used in the present application, unless it is indicated that the end value is not included, the two end values of the range are included by default, for example, within 1 to 5, including 1 and 5 two numerical values.

[0048] Coupling: can be understood as direct coupling and / or indirect coupling, and "coupling connection" can be understood as direct coupling connection and / or indirect coupling connection. Direct coupling can also be referred to as "electrical connection", which is understood as physical contact and electrical conduction of components; it can also be understood as a form of connection between different components in a circuit structure through a signal-transmissible physical line such as a copper foil or a wire of a printed circuit board (PCB); "indirect coupling" can be understood as electrical conduction between two conductors through a space without contact. In an embodiment, indirect coupling can also be referred to as capacitive coupling, for example, through the coupling between the gap between two conductive parts to form an equivalent capacitor to achieve signal transmission.

[0049] Radiating body: is a device in an antenna for receiving / sending electromagnetic wave radiation. In some cases, "antenna" is understood in a narrow sense as a radiating body, which changes the guided wave energy from a transmitter into radio waves, or converts radio waves into guided wave energy, for radiating and receiving radio waves. The modulated high-frequency current energy (or guided wave energy) generated by the transmitter is transmitted to the transmitting radiating body through the feeder, which is converted into electromagnetic wave energy of a certain polarization by the radiating body and radiated in the desired direction. The receiving radiating body converts electromagnetic wave energy of a certain polarization from a certain direction in space into modulated high-frequency current energy, which is delivered to the input end of the receiver through the feeder.

[0050] The radiating body can include a conductor with a specific shape and size, such as a wire or a sheet, and the present application does not limit the specific shape.

[0051] Feeder circuit: is a circuit for receiving and / or transmitting radio frequency signals. The feeder circuit can include a transceiver and a radio frequency front end circuit (RF front end). In some cases, "feeder circuit" is understood in a narrow sense as a radio frequency integrated circuit (RFIC), which can be considered to include a radio frequency front end circuit (or radio frequency front end chip) and a transceiver. The feeder circuit has the function of converting radio waves (e.g., radio frequency signals) and signals (e.g., digital signals). In general, it is considered to be part of the radio frequency.

[0052] In some embodiments, the electronic device can also include a test seat (or also referred to as a radio frequency seat or a radio frequency test seat). The test seat can be used to insert a coaxial cable to test the characteristics of the radio frequency front end circuit or the radiating body of the antenna through the cable. The radio frequency front end circuit can be considered as a circuit part coupled between the test seat and the transceiver.

[0053] In some embodiments, the radio frequency front-end circuit can be integrated into a radio frequency front-end chip in the electronic device, or the radio frequency front-end circuit and the transceiver can be integrated into a radio frequency chip in the electronic device.

[0054] The ground structure / feeding structure can include a connecting member, such as a metal column, and the radiating body is coupled to the floor through the ground structure, or the radiating body is coupled to the feeding circuit through the feeding structure. In some embodiments, the feeding structure can include a feeding point and / or a microstrip line electrically connected to the feeding point, and the ground structure can include a grounding point.

[0055] End / point: the "end / point" in the first end / second end / feeding end / ground end / feeding point / ground point / connecting point of the antenna radiating body should not be understood as a point or end physically disconnected from other radiating bodies, but can also be considered as a point or section on a continuous radiating body. In an embodiment, the "end / point" can include a connecting / coupling area of the antenna radiating body or the microstrip line that is coupled to other conductive structures, for example, the feeding end / feeding point can be a connecting / coupling area of the antenna radiating body that is coupled to the feeding structure or the feeding circuit (for example, an area facing a part of the feeding circuit), and for another example, the ground end / ground point can be a connecting / coupling area of the antenna radiating body that is coupled to the ground structure or the ground circuit (for example, an area facing a part of the ground circuit).

[0056] Resonance / resonance frequency: resonance frequency is also called resonance frequency. The resonance frequency can have a frequency range, that is, a frequency range in which resonance occurs. The frequency corresponding to the strongest resonance point is the center frequency point frequency. The return loss characteristic of the center frequency can be less than -20 dB. It should be understood that, unless otherwise specified, the antenna / radiating body mentioned in this application produces "first / second … resonance", wherein the first resonance is the fundamental mode resonance produced by the antenna / radiating body, or in other words, the resonance with the lowest frequency produced by the antenna / radiating body. It should be understood that the antenna / radiating body can produce one or more antenna modes according to the specific design, and each antenna mode can correspond to a fundamental mode resonance.

[0057] Resonance frequency band: the range of resonance frequencies is the resonance frequency band, and the return loss characteristic of any frequency point in the resonance frequency band can be less than -6 dB or -5 dB.

[0058] Communication frequency band / working frequency band: no matter what type of antenna, it always works in a certain frequency range (bandwidth). For example, an antenna supporting the B40 frequency band has a working frequency band including frequencies in the range of 2300 MHz to 2400 MHz, or in other words, the working frequency band of the antenna includes the B40 frequency band. The frequency range that meets the index requirements can be regarded as the working frequency band of the antenna.

[0059] The resonant frequency band and the operating frequency band can be the same or can partially overlap. In one embodiment, one or more resonant frequency bands of an antenna can cover one or more operating frequency bands of the antenna.

[0060] Wavelength: or operating wavelength, can be the wavelength corresponding to the center frequency of the resonant frequency or the center frequency of the operating frequency band supported by the antenna. For example, assuming the center frequency of the B1 uplink frequency band (resonant frequency of 1920-1980 MHz) is 1955 MHz, the operating wavelength can be the wavelength calculated using the frequency of 1955 MHz. Without being limited to the center frequency, the "operating wavelength" can also refer to the wavelength corresponding to a non-center frequency of the resonant frequency or the operating frequency band.

[0061] It should be understood that the wavelength of the radiated signal in air can be calculated as follows: (air wavelength, vacuum wavelength, or free space wavelength) = speed of light / frequency, where the frequency is the frequency of the radiated signal (Hz), and the speed of light can be taken as 3 x 10 8 m / s. The wavelength of the radiated signal in a medium can be calculated as follows: where ε is the relative permittivity of the medium.

[0062] Antenna system efficiency (total efficiency): also referred to as total efficiency, refers to the ratio of the power radiated by the antenna into space (i.e., the power effectively converted into electromagnetic waves) to the input power at the port of the antenna.

[0063] Antenna radiation efficiency: refers to the ratio of the power radiated by the antenna into space (i.e., the power effectively converted into electromagnetic waves) to the active power input to the antenna. The active power input to the antenna = input power of the antenna - reflected power - power coupled to other ports; the loss power mainly includes the backwave loss power and the ohmic loss power of the metal and / or the dielectric loss power. The radiation efficiency is a value that measures the radiation capability of the antenna, and the metal loss and the dielectric loss are both factors affecting the radiation efficiency.

[0064] As can be understood by those skilled in the art, efficiency is generally expressed in percentage, and there is a corresponding conversion relationship between efficiency and dB, and the closer the efficiency is to 0 dB, the better the efficiency of the antenna is represented.

[0065] Antenna backwave loss: can be understood as the ratio of the signal power reflected back to the antenna port through the antenna circuit to the transmission power of the antenna port. Generally speaking (taking into account that part of the energy can also be coupled to other ports), the smaller the reflected signal, the greater the signal radiated by the antenna into space, and the greater the total efficiency of the antenna. The greater the reflected signal, the smaller the signal radiated by the antenna into space, and the smaller the total efficiency of the antenna.

[0066] Antenna return loss can be represented by |S 11 | parameter, |S 11 | is one of the parameters in S parameter. |S 11 | can represent the reflection coefficient, which can represent the pros and cons of the antenna reflection coefficient. For passive antennas, |S 11 | is usually negative in dB unit, |S 11 | parameter value is smaller, the smaller the antenna return loss, the smaller the energy reflected back by the antenna itself, that is, the more energy actually enters the antenna; |S 11 | parameter value is larger, the larger the antenna return loss.

[0067] It should be noted that in engineering, |S 11 | value of -6dB or -10dB can be used as a standard, when the |S 11 | value of the antenna satisfies less than or equal to -6dB or -10dB, it can be considered that the antenna can work normally, or it can be considered that the antenna has better transmission efficiency.

[0068] Antenna pattern: also known as radiation pattern. It refers to the relative field strength (normalized modulus) of the antenna radiation field at a certain distance from the antenna (far field) changes with direction pattern, 2D pattern is usually represented by two mutually perpendicular plane patterns through the maximum radiation direction of the antenna.

[0069] Antenna gain: used to represent the degree of concentration of input power radiated by the antenna. Generally, the narrower the main lobe of the antenna pattern, the smaller the sidelobe, the higher the antenna gain.

[0070] Reflector: The reflector can also be referred to as a floor, a bottom plate, an antenna panel, a metal reflector, etc. The reflector is generally a metal plate, which can have an electrical effect on the antenna. For example, the reflector can be used to improve the receiving sensitivity of the antenna signal, and the antenna signal is reflected and combined at the receiving point, thereby enhancing the receiving and transmitting capabilities of the antenna. It also plays a role in blocking and shielding the electric waves from the back of the reflector (the direction opposite to the radiation direction of the antenna) to interfere with the antenna, and enhancing the directivity of the antenna. The reflector can also be used as the main structure of the antenna to carry the array of radiating elements and the feed network. In the embodiments of the present application, the reflector can also be referred to as a second metal layer.

[0071] Any of the above ground planes, or ground planes, or ground metal layers are made of conductive material. In one embodiment, the conductive material can be any of the following: copper, aluminum, stainless steel, brass, and alloys thereof, copper foil on an insulating substrate, aluminum foil on an insulating substrate, gold foil on an insulating substrate, silver plated copper, silver plated copper foil on an insulating substrate, silver foil on an insulating substrate, and tin plated copper, graphite powder impregnated cloth, graphite coated substrate, copper plated substrate, brass plated substrate, and aluminum plated substrate. Those skilled in the art will appreciate that the ground plane / ground plane / ground metal layer can also be made of other conductive materials.

[0072] Feed network: A feed network is an important component in an antenna, connecting the antenna port and the radiator, forming a signal transmission path, and capable of achieving impedance matching, amplitude and phase distribution, etc. The main function of the feed network is to feed the signal from the transmitter to the radiator according to a certain amplitude and phase, or to send the wireless signal received from the radiator to the receiver according to a certain amplitude and phase. The feed network usually includes a controlled impedance transmission line. In some embodiments, the feed network can also include a phase shifter. In some embodiments, the feed network can also include combiners, filters, etc.

[0073] Ground: refers to coupling with the above-mentioned ground / ground plane in any way. In one embodiment, the ground can be physical ground, such as physical ground on the edge frame at a certain position through part of the structure of the middle frame (or referred to as physical ground). In one embodiment, the ground can be device ground, such as device ground through series or parallel capacitors / inductors / resistors, etc. (or referred to as device ground).

[0074] Antenna array: An antenna array is an array structure composed of at least one antenna arranged according to a certain geometric rule, and the at least one antenna can share the same feed network for work.

[0075] FIG. 1 shows a schematic diagram of an architecture of a communication system 100 to which embodiments of the present application are applicable. As shown in FIG. 1, the communication system 100 can include a base station 101 and a terminal 102, and the base station 101 and the terminal 102 can implement wireless communication.

[0076] In embodiments, a terminal 102 can be referred to as a user equipment, an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, a remote terminal, a mobile device, a user terminal, a terminal device, a wireless communication device, a user agent, or a user device. By way of example, and without limitation, a terminal 102 can be a cellular telephone, a cordless telephone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless communication functions, a computing device, or other processing devices connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolved public land mobile network (PLMN), etc. Embodiments are not limited to the type of terminal 102.

[0077] In the embodiments of the present application, the base station 101 can also be referred to as an access network device. The base station 101 can be located in a base station subsystem (BSS), a universal terrestrial radio access network (UTRAN), or an evolved universal terrestrial radio access network (E-UTRAN), and is used for cell coverage of signals to realize communication between the terminal and the wireless network. As an example but not limitation, the base station 101 can be a base transceiver station (BTS) in a global system for mobile communication (GSM) system or a code division multiple access (CDMA) system, a node B (NodeB, NB) in a wideband code division multiple access (WCDMA) system, an evolved NodeB (eNB or eNodeB) in a long term evolution (LTE) system, a next generation base station node (gNB) in a new radio (NR) system, a wireless controller in a cloud radio access network (CRAN) scenario, or can be a relay station, an access point, a vehicle-mounted device, a wearable device, and a network device in future networks, etc., and the embodiments of the present application are not limited thereto.

[0078] In the embodiments of the present application, the base station 101 is configured with a base station antenna feeder system to realize transmission of signals in space, and the base station antenna feeder system includes an antenna and a radio frequency unit connected to the antenna.

[0079] In order to improve the spectrum efficiency of the wireless communication system, the prior art proposes the MU-MIMO technology, which improves the spectrum efficiency by using time division, frequency division or orthogonal coding. The spatial division multiplexing is also used to eliminate the interference between multiple users by using different precoding for each user. The traditional spatial division multiplexing is based on the orthogonality of the electromagnetic wave in the polarization domain and the beamforming between the array elements to reduce the interference between multiple users. However, due to the limited number of orthogonal polarization components, how to further increase the number of orthogonal beams in the limited aperture is a problem to be solved. The existing theory can analyze the characteristic mode of the physical antenna structure, and generate radiation patterns with good orthogonality by exciting different modes. The multi-mode multi-port antenna designed based on this method can increase the number of antenna ports in the limited aperture. The multiple radiation patterns generated by excitation can be used for MIMO signal transmission to improve the spectrum efficiency of the wireless communication system under the limited antenna aperture.

[0080] In actual product forms such as macro base stations or micro base stations, the size of the antenna is often limited. In order to obtain higher communication performance such as spectrum efficiency under the limited antenna aperture, a new design method needs to be used to design the antenna. The traditional dual-polarized array antenna only regulates the excitation coefficient between the array elements, and does not regulate the element pattern. The existing literature contains multi-port antenna elements, but due to the structural characteristics, the number of ports is often small, or the coupling between the ports is strong, and the three-dimensional structure used is too complex. Some antenna designs require special feeding networks, which also cause additional loss and reduce the overall efficiency of the antenna. In order to solve the above problems, the scheme of the present application proposes a dense multi-port antenna element, which has the characteristics of planarization and easy processing, and can improve the port density while ensuring a certain isolation.

[0081] The possible antenna structure provided by the embodiment of the present application will be described in detail below with reference to FIGS. 2-15.

[0082] In the z-axis direction, the antenna can sequentially include a first metal layer, a first dielectric substrate and a second metal layer, and the z-axis direction is perpendicular to the plane where the first metal layer or the second metal layer is located. The N feeding structures coupled to the first metal layer and the second metal layer can feed the first metal layer, the first metal layer and the feeding structure can radiate a beam, and the second metal layer can reflect the radiated beam. Hereinafter, the first metal layer and the feeding structure will be taken as an example to describe in detail a possible antenna structure provided by the embodiment of the present application.

[0083] FIG. 2 and FIG. 3 are schematic diagrams of a projection of a first metal layer in a z-axis direction according to embodiments of the present application. As shown in FIG. 2 or FIG. 3, the part filled with diagonal lines in FIG. 2 or FIG. 3 represents the first metal layer, which can be a metal layer satisfying circular symmetry, or the first metal layer can have a certain thickness along the z-axis direction and a surface of the first metal layer perpendicular to the z-axis direction satisfying circular symmetry.

[0084] Circular symmetry can also be referred to as rotational symmetry. A pattern satisfying circular symmetry can coincide with the pattern before rotation after the pattern is rotated by a certain angle around the center of circular symmetry. For example, the pattern can be a circle, or when the pattern is an equilateral triangle, the pattern obtained after rotating the equilateral triangle by 120° / 240° around the center of symmetry of the equilateral triangle can coincide with the equilateral triangle before rotation. Alternatively, for example, as shown in (a) of FIG. 2, the first metal layer satisfies a circularly symmetric pattern of a "cross", and the pattern obtained after rotating the "cross" by 90° / 180° / 270° around the center of symmetry of the "cross" can coincide with the "cross" before rotation; as shown in (b) of FIG. 2, the first metal layer satisfies a circularly symmetric pattern of a regular hexagon, and the pattern obtained after rotating the regular hexagon by 60° / 120° / 180° / 240° / 300° around the center of symmetry of the regular hexagon can coincide with the regular hexagon before rotation; as shown in (a) of FIG. 3, the first metal layer satisfies a circularly symmetric pattern of a square, and the pattern obtained after rotating the square by 90° / 180° / 270° around the center of symmetry of the square can coincide with the square before rotation; as shown in (b) of FIG. 3, the first metal layer satisfies a circularly symmetric pattern of a four-corner curved quadrilateral, and the pattern obtained after rotating the four-corner curved quadrilateral by 90° / 180° / 270° around the center of symmetry of the four-corner curved quadrilateral can coincide with the four-corner curved quadrilateral before rotation. It can be understood that the above description is only an example of the shape of the first metal layer, and any first metal layer satisfying circular symmetry can be included in the embodiments of the present application, which are not limited in this regard.

[0085] The size of the first metal layer can be designed according to the performance requirements of the antenna and the product structure. In the embodiments of the present application, when the antenna is used for communication at X GHz frequency, the length of the first metal layer along the first direction is less than or equal to C / (2X), and / or the length of the first metal layer along the second direction is less than or equal to C / (2X), the plane composed of the first direction and the second direction is perpendicular to the z-axis direction, that is, the plane composed of the first direction and the second direction is parallel to the plane where the first metal layer or the second metal layer is located, and C represents the speed of light in free space. In the embodiments of the present application, C can be 3x10 8 m / s.

[0086] In some possible implementation manners, the first direction and the second direction are perpendicular. For example, as shown in FIG. 2, the x direction is parallel to the first direction, the y direction is parallel to the second direction, the length of the first metal layer along the x direction is less than or equal to C / (2X), and / or, the length of the first metal layer along the y direction is less than or equal to C / (2X).

[0087] In some possible implementation manners, the first direction and the second direction are not perpendicular. For example, as shown in FIG. 3, the x' direction is parallel to the first direction, the y' direction is parallel to the second direction, the included angle between the x' direction and the y' direction is less than 90° and greater than 0°. The length of the first metal layer along the x' direction is less than or equal to C / (2X), and / or, the length of the first metal layer along the y' direction is less than or equal to C / (2X).

[0088] Based on the scheme provided in the embodiments of the present application, by including multiple ports in the antenna aperture less than or equal to half free space wavelength multiplied by half free space wavelength, the frequency spectrum efficiency can be improved in the limited antenna aperture.

[0089] In some possible implementation manners, the N feed structures for feeding the first metal layer correspond to the N ports of the antenna one by one, each port can transmit a signal to the radiator through the corresponding feed structure, and N is an integer greater than or equal to 3.

[0090] For example, the feed structure can be a solid cylinder or a hollow cylinder extending along the z-axis direction, and the projection of the feed structure on the first metal layer satisfies circular symmetry. For example, when the feed structure is a cylinder, the projection of the feed structure on the first metal layer is a circle satisfying circular symmetry, or when the feed structure is a cylinder with a cross section of a regular polygon, the projection of the feed structure on the first metal layer is a regular polygon satisfying circular symmetry.

[0091] For example, the feed hole can be a metal hole formed by metalizing the hole wall of the through hole at the corresponding position of the feed structure and the first dielectric substrate, and the projection of the metal hole on the first metal layer satisfies circular symmetry. For example, when the through hole at the corresponding position of the feed structure and the first dielectric substrate is a cylindrical hole, the projection of the feed structure on the first metal layer is a circle satisfying circular symmetry, or when the through hole at the corresponding position of the feed structure and the first dielectric substrate is a cylindrical hole with a cross section of a regular polygon, the projection of the feed structure on the first metal layer is a regular polygon satisfying circular symmetry.

[0092] In some possible implementation manners, the N feed structures include one first feed structure and M second feed structures, M is an integer less than N and greater than 1; the first feed structure has a projection on the first metal layer, and a distance between the projection and a geometric center of the first metal layer is less than or equal to a first threshold; the M second feed structures surround the first feed structure, and the M second feed structures are arranged to satisfy circular symmetry, and the N feed structures form a circular symmetric structure.

[0093] For example, a first feed structure of the N feed structures has a projection on the first metal layer, and the projection is located near a geometric center of the first metal layer, and M second feed structures of the N feed structures surround the first feed structure. The structure formed by the N feed structures extends along the z-axis direction, and the projection of the structure formed by the N feed structures on the first metal layer can satisfy circular symmetry, that is, the N feed structures form a circular symmetric structure.

[0094] Based on the scheme provided in the embodiments of the present application, the radiator of the antenna includes a first metal layer satisfying circular symmetry and a feed structure, and a second feed structure surrounds the first feed structure. On the one hand, the scheme can make the radiation patterns of different ports of the antenna orthogonal, thereby ensuring the isolation between the ports, improving the spectrum efficiency, and reducing the signal interference between multiple users. On the other hand, the distance between the projection of the first metal layer and the feed structure on the z-axis direction is less than or equal to a first threshold, and the value of the first threshold can be as small as possible, so that the symmetry of the radiation of the antenna in space is better.

[0095] In a possible implementation manner, part or all of the feed structure is located in the first dielectric substrate.

[0096] For example, when the feed structure is a column, the first dielectric substrate and the corresponding part of the feed structure include a through hole, and the size of the through hole is greater than or equal to the size of the feed structure, so that the first part of the feed structure can be accommodated in the through hole. The first part is the part of the feed structure parallel to the z-axis and located between the first metal layer and the second metal layer. Alternatively, the first dielectric substrate and the corresponding part of the feed structure include a through hole, the feed structure includes a metal hole formed by metalizing the hole wall of the through hole, and the first part of the feed structure is the metal hole. When the feed structure is electrically connected to the first metal layer, the second part of the feed structure can not be located in the through hole of the first dielectric substrate. The second part is the part electrically connecting the first part of the feed structure and the first metal layer, that is, part of the feed structure is located in the first dielectric substrate. When the feed structure is indirectly coupled to the first metal layer and the feed structure does not pass through the first metal layer along the z-axis direction (that is, the feed structure has a distance from the lower surface of the first metal layer along the z-axis direction, and the distance is greater than or equal to 0), that is, part or all of the feed structure is located in the first dielectric substrate. When the first dielectric substrate is a structure with a space entity, the first metal layer and / or the second metal layer can be attached to the upper surface or the lower surface of the dielectric substrate.

[0097] According to the scheme provided in the embodiments of the present application, the first metal layer and the second metal layer of the antenna include a dielectric substrate. On the one hand, the dielectric constant of the dielectric substrate can be greater than that of air, so as to reduce the size of the antenna. On the other hand, the dielectric substrate with a space entity can provide an attachment position for the first metal layer and / or the second metal layer, so that the relative position of the first metal layer and the second metal layer can be kept stable.

[0098] It can be understood that when N satisfies N=3 and M satisfies M=2, the antenna has three ports, and the first metal layer can satisfy a 180° circular rotation; when N satisfies N=4 and M satisfies M=3, the antenna has four ports, and the first metal layer can satisfy a 120° circular rotation; and when N satisfies N=7 and M satisfies M=6, the antenna has seven ports, and the first metal layer can satisfy a 60° circular rotation. The embodiments of the present application do not limit this.

[0099] For the convenience of description and understanding, the following text of the present application takes N satisfying N=5 and M satisfying M=4 as an example to describe a possible antenna structure provided in the embodiments of the present application.

[0100] The part of the first metal layer corresponding to the feeding structure can have a through hole. As shown in FIGS. 4(a), 4(b), 4(c) and 4(d), FIG. 4 is a schematic diagram of the projection of the first metal layer in the z-axis direction according to another embodiment of the present application. The part filled with diagonal lines in FIG. 4 represents the first metal layer, and the part not filled in FIG. 4 represents the through hole of the first metal layer. The through hole located at the center of the first metal layer can be coupled to the first feeding structure, and the four through holes surrounding the center of the first metal layer can be coupled to the second feeding structure, respectively.

[0101] For example, when the feeding structure is electrically connected to the first metal layer, one end of the feeding structure is electrically connected to the first metal layer, and the other end of the feeding structure is connected to the port. When the feeding structure is indirectly coupled to the first metal layer, one end of the feeding structure is indirectly coupled to the first metal layer, and the other end of the feeding structure is connected to the port. The first feeding structure is connected to the port 1, and the four second feeding structures are connected to the port 2, the port 3, the port 4 and the port 5, respectively. FIG. 5 is a schematic diagram of the arrangement of the port positions according to an embodiment of the present application. The part filled with points in FIG. 5 represents the second metal layer.

[0102] In some possible implementation manners, the first metal layer and the feeding structure form a stepped structure along the z-axis direction.

[0103] For example, one or more of the five feeding structures can pass through the first metal layer along the z-axis direction; and / or, along the z-axis direction, the distance between one or more of the five feeding structures and the lower surface of the first metal layer can be greater than 0.

[0104] In some possible implementations, the second metal layer can be a metal layer that satisfies circular symmetry, or the second metal layer can have a certain thickness along the z-axis and the surface of the second metal layer perpendicular to the z-axis satisfies circular symmetry. The distance between the projection of the geometric center of the second metal layer onto the geometric center of the first metal layer is less than or equal to a third threshold. The second metal layer is coupled to five feed structures, and the first dielectric substrate is located between the first and second metal layers.

[0105] It is understood that the patterns of the second metal layer and the first metal layer can be the same or different. As long as the circular symmetry angles of the second metal layer and the first metal layer are the same, they can be included in the embodiments of this application. The embodiments of this application do not limit this.

[0106] For example, the pattern of the second metal layer can be a diameter equal to The first metal layer can be a regular quadrilateral with a side length of C / (2X). The second metal layer has a different pattern than the first metal layer, but the first metal layer satisfies the circular symmetry angles of 90° / 180° / 270° and the second metal layer can also satisfy the circular symmetry angles of 90° / 180° / 270°.

[0107] In some possible implementations, the first metal layer may also be referred to as the first metal pattern, and the second metal layer may also be referred to as the second metal pattern.

[0108] In some possible implementations, the antenna also includes a grounding structure, which is coupled to the first metal layer and electrically connected to the second metal layer.

[0109] In some possible implementations, the arrangement of the grounding structure satisfies circular symmetry, and the grounding structure can form a circular symmetrical structure.

[0110] For example, the antenna may include four first grounding structures, each corresponding to one of four second feeding structures, and the four first grounding structures corresponding to the second feeding structures are arranged in a ring around the first feeding structures.

[0111] For example, the antenna may also include four second grounding structures, which correspond one-to-one with four second feeding structures. The four second grounding structures corresponding to the second feeding structures surround the first feeding structure.

[0112] For example, in the multiple second grounding structures included in the antenna, any one second grounding structure can correspond to multiple second feeding structures. For instance, two second feeding structures can share one second grounding structure. This application does not limit this aspect.

[0113] Exemplarily, the antenna can further include 4n second ground structures, n second ground structures in the 4n second ground structures are a group (i.e., the 4n second ground structures can form 4 groups of second ground structures, each second ground structure in any group of second ground structures is different from the second ground structures in other groups of second ground structures), the 4 groups of second ground structures correspond to the 4 second feeding structures one by one, and n is a positive integer. The 4n second ground structures corresponding to the second feeding structures surround the first feeding structure.

[0114] It can be understood that the arrangement of the ground structures satisfies circular symmetry in the projection of the first metal layer, and the angle at which the arrangement of the ground structures satisfies circular symmetry in the projection of the first metal layer is the same as the angle at which the arrangement of the feeding structures satisfies circular symmetry in the projection of the first metal layer.

[0115] Based on the scheme provided in the embodiments of the present application, by arranging the ground structures of the antenna corresponding to the feeding structures, on the one hand, the length of the current flowing in the loop in the limited antenna aperture can satisfy the required half-free-space wavelength of the resonance condition, which is conducive to the miniaturization of the antenna; on the other hand, by arranging multiple ground structures for one feeding structure, the miniaturization of the antenna can be better achieved, and the isolation between the ports can be increased; and on the other hand, the ground structures can also satisfy circular symmetry, which can further achieve the symmetry of the antenna pattern.

[0116] In some possible implementation manners, the first metal layer includes a first ring-shaped gap, and the first ring-shaped gap is located around the projection of the first feeding structure on the first metal layer.

[0117] In some possible implementation manners, the first metal layer includes a second ring-shaped gap, and the second ring-shaped gap is located around the projection of the second feeding structure on the first metal layer.

[0118] FIG. 6 is a schematic diagram of a projection of a first metal layer in the z-axis direction according to an embodiment of the present application. In FIG. 6, the oblique line filled part represents a metal part of the first metal layer, and the unfilled part represents a through hole of the first metal layer. FIG. 7 is a schematic diagram of a projection of an antenna in the z-axis direction according to an embodiment of the present application. In FIG. 7, the oblique line filled part represents a metal part of the first metal layer, the unfilled part represents a first dielectric substrate, the horizontal line filled part represents a ground structure, and the vertical line filled part represents a feeding structure. As shown in FIGS. 6 and 7, when the first metal layer is placed on the upper surface of the first dielectric substrate, the through hole of the first metal layer in the z-axis direction can expose the first dielectric substrate.

[0119] The first metal layer shown in (a) of FIG. 6 includes 9 circular through holes, wherein the circular through hole located at the geometric center of the first metal layer corresponds to the first feeding structure, and the circular through holes located at the four edges of the first metal layer correspond to 4 second feeding structures and 4 first grounding structures respectively. The first metal layer shown in (b) of FIG. 6 includes 13 circular through holes, wherein the circular through hole located at the geometric center of the first metal layer corresponds to the first feeding structure, and the circular through holes located at the four edges of the first metal layer correspond to 4 second feeding structures, 4 first grounding structures and 4 second grounding structures respectively. The first metal layer shown in (c) of FIG. 6 includes 21 circular through holes, wherein the circular through hole located at the geometric center of the first metal layer corresponds to the first feeding structure, the circular through holes located at the four edges of the first metal layer correspond to 4 first grounding structures respectively, and the circular through holes located at the four corners of the first metal layer correspond to 4 second feeding structures and 4*3=12 second grounding structures respectively.

[0120] When the diameter of the circular through hole of the first metal layer is greater than the diameter of the projection of the corresponding feeding structure on the first metal layer, the first metal layer and the feeding structure can form a first annular slot and / or a second annular slot in the plane where the first metal layer is located.

[0121] FIG. 8 is a schematic diagram of the projection of another antenna in the z-axis direction according to an embodiment of the present application. In FIG. 8, the oblique line filled part represents the first metal layer, the dot filled part represents the second metal layer, the unfilled part represents the first dielectric substrate, the horizontal line filled part represents the grounding structure, and the vertical line filled part represents the feeding structure. As shown in FIG. 7 and FIG. 8, the first metal layer and the feeding structure form a first annular slot and / or a second annular slot in the plane where the first metal layer is located.

[0122] Based on the scheme provided in the embodiments of the present application, the capacitive impedance can be generated through the annular slot formed between the first metal layer and the feeding structure, and the inductive impedance generated by the feeding structure is offset, so that the impedance matching of the antenna can be improved.

[0123] In some possible implementation manners, the first metal layer includes a third annular slot, and the third annular slot is located around the projection of the first grounding structure on the first metal layer.

[0124] When the diameter of the circular through hole of the first metal layer is greater than the diameter of the projection of the corresponding first grounding structure on the first metal layer, the first metal layer and the first grounding structure can form a third annular slot in the plane where the first metal layer is located.

[0125] As shown in FIG. 7 or FIG. 8, the first metal layer and the first grounding structure can form a third annular slot in the plane where the first metal layer is located.

[0126] Based on the scheme provided in the embodiments of the present application, the capacitive impedance can be generated through the annular gap formed between the first metal layer and the first grounding structure, so that the impedance matching of the antenna can be further improved.

[0127] The port of the antenna with the structure shown in FIG. 7 is removed, the second metal layer is set to be infinite, the eigenmode analysis is performed on the antenna with the structure, and the eigenvalue distribution of the structure is obtained. By adjusting the structure parameters, it can be ensured that the absolute values of m eigenvalues are less than a threshold value near the target frequency point, and it is considered that the structure supports the eigenmode corresponding to the eigenvalues, and it is proved that the structure can support an antenna with less than or equal to m ports. According to the eigenmode analysis, the eigenvalues of 5 modes of the above structure are located between ±2, which indicates that the structure supports 5 modes. Among them, mode 1 corresponds to port 1, and modes 2-5 correspond to ports 2-5, respectively.

[0128] The antennas with the structures shown in FIG. 7 and FIG. 5 are subjected to full-wave simulation, different antenna ports are excited respectively, and other ports are set to be connected to a matching load by default. The radiation patterns obtained by simulation are shown in FIG. 9. FIG. 9 is a radiation pattern of a port of an antenna with the structure shown in FIG. 7 and FIG. 5. FIG. 9(a) shows a three-dimensional diagram of the radiation pattern obtained by exciting port 1 at a frequency of 3 GHz; FIG. 9(b) shows a diagram of a cut surface radiation pattern obtained by exciting port 1 at a frequency of 3 GHz; FIG. 9(c) shows a three-dimensional diagram of the radiation pattern obtained by exciting port 2 at a frequency of 3 GHz; FIG. 9(d) shows a diagram of a cut surface radiation pattern obtained by exciting port 2 at a frequency of 3 GHz; the directions of the main beams of ports 2-5 corresponding to modes 2-5 at a frequency of 3 GHz are near the x-axis or y-axis and slightly inclined, and FIG. 9(e) shows the projection of the main beams of ports 2-5 in a plane perpendicular to the z-axis direction (for example, on the xy plane). Specifically, as shown in FIG. 9(a) and FIG. 9(b), mode 1 is an omnidirectional beam, and the radiation pattern of port 1 is an omnidirectional pattern with a beam maximum up-tilt. The reason for the beam up-tilt may be the reflector effect caused by the second metal layer. As shown in FIG. 9(c) and FIG. 9(d), the far-field pattern of mode 2 is close to a broadside direction, and the radiation pattern of port 2 is a directional broadside beam with a slightly inclined main beam direction. The pattern of mode 1 is obviously different from the pattern of mode 2. In the antenna with the structure shown in FIG. 7 and FIG. 5, the polarizations of modes 2 and 3 are different, and the polarizations of modes 4 and 5 are different. Although the outer circle current distribution of modes 2 and 4 is different by 180°, the inner circle current is different, thus leading to the orthogonality of the far-field patterns of modes 2 and 4. The analysis of modes 3 and 5 is similar to the analysis of modes 2 and 4. Therefore, the patterns of ports 1-5 satisfy the orthogonality. As can be seen from the radiation pattern of port 2, the beam width of port 2 at 3 dB is 65°. Due to the circular symmetry of the structure of the antenna, the analysis of ports 3-5 is similar to the analysis of port 2.

[0129] Figure 10 is a diagram of simulation results of reflection coefficient, isolation and total efficiency of ports of the antenna with the structure shown in Figures 7 and 5. In Figure 10, |S 11 | represents the reflection coefficient of port 1, |S 21 | represents the isolation of port 2 and port 1, |S 22 | represents the reflection coefficient of port 2, |S 32 | represents the isolation of port 3 and port 2.

[0130] Figure 10(a) is the reflection coefficient and port isolation of port 1 and port 2, and Figure 10(b) is the total efficiency of port 1 and port 2. Since the structure of the antenna shown in Figures 7 and 5 satisfies circular symmetry, the reflection coefficient and isolation of ports 3-5 are similar to those of port 2. As can be seen from the Q point and the P point in Figure 10(a), the antenna achieves a bandwidth of 5.7% at 3 GHz; as can be seen from the H point in Figure 10(a), the isolation of port 2 and port 1 is greater than 9.8 dB. As can be seen from the Q' point in Figure 10(b), the total efficiency of port 1 is 28% at 3 GHz, and as can be seen from the P' point in Figure 10(b), the total efficiency of port 2 is 46% at 3 GHz, which may be due to the influence of the coupling of the connected ports and the material loss.

[0131] It can be understood that the shape and position arrangement of the through hole in the first metal layer described above are only examples, and the through hole can be circular, regular polygonal, or irregular shape, which is not limited in the embodiments of the present application.

[0132] It can be understood that the first annular slot, the second annular slot, or the third annular slot described above can be a regular polygonal slot or an irregularly shaped slot. The embodiments of the present application are not limited in this regard.

[0133] In some possible implementations, the N feed structures and / or the M first ground structures can be electrically connected to the first metal layer through N first annular metals and / or M second annular metals, the N first annular metals corresponding one-to-one to the N feed structures, and the M second annular metals corresponding one-to-one to the M first ground structures. It can be understood that the inner circle radius of the first annular metal can be equal to the radius of the projection of the corresponding feed structure on the first metal layer; the inner circle radius of the second annular metal can be equal to the radius of the projection of the corresponding first ground structure on the first metal layer. The first annular metal and / or the second annular metal are not shown in other drawings outside Figure 8.

[0134] It can be understood that the shape of the first annular metal / second annular metal is only an example, and the annular metal can be a circular ring, or a ring with a regular polygonal outer edge, or a ring satisfying an irregular shape. The material of the first annular metal / second annular metal can be the same as that of the first metal layer, or can be different from that of the first metal layer; the material of the first annular metal / second annular metal can be the same as that of the feed structure / ground structure, or can be different from that of the feed structure / ground structure. The embodiments of the present application do not limit this.

[0135] In some possible implementation manners, the width of the first annular gap satisfies d=1.86 mm. For example, as shown in FIG. 8, the part filled with cross lines in FIG. 8 represents the first annular metal or the second annular metal. In the structure shown in FIG. 8, the first annular gap / second annular gap can be: in the plane where the first metal layer is located, the part of the first dielectric substrate exposed between the first annular metal and the via of the first metal layer, and the width of the first annular gap is the width of the dielectric substrate exposed near the first annular metal along the direction perpendicular to the z axis (for example, the radius of the via of the first metal layer corresponding to the first feed structure in FIG. 8 satisfies d1=2.3 mm, the radius of the outer ring of the first annular metal satisfies d2=0.44 mm, and the radius of the projection of the first feed structure on the first metal layer satisfies d3=0.24 mm). In the structure shown in FIG. 8, the third annular gap can be: in the plane where the first metal layer is located, the part of the first dielectric substrate exposed between the second annular metal and the via of the first metal layer.

[0136] It can be understood that when the via located in the first metal layer is a regular polygon and the first annular metal is also a regular polygon, the annular gap can be a gap satisfying the regular polygon, and the width of the annular gap can refer to the width between any one side of the via of the first metal layer satisfying the regular polygon and the outer edge of the first annular metal, that is, the distance of the dielectric substrate exposed between the first annular metal and the via of the first metal layer along the width direction, and the width direction can be a direction perpendicular to one side of the regular polygon and perpendicular to the z axis.

[0137] FIG. 11 is a schematic diagram of the projection of a microstrip line in the z axis direction according to an embodiment of the present application. The part filled with oblique lines in FIG. 11 is a metal part.

[0138] In some possible implementation manners, the antenna further includes N microstrip lines and a second dielectric substrate. Each microstrip line is configured to transmit a signal to a corresponding feed structure; M microstrip lines of the N microstrip lines satisfy circular symmetry in the projection on the first metal layer, and the M microstrip lines are coupled to M second feed structures.

[0139] As shown in (a) of FIG. 11, (a) of FIG. 11 includes five microstrip lines, a first end of each microstrip line is coupled to a 5 feeding structure respectively, and a second end of each microstrip line is connected to a coaxial connector through a grounded coplanar waveguide (a trapezoidal part in (a) of FIG. 11).

[0140] Based on the scheme provided in the embodiments of the present application, the signal of the excitation port is provided through the microstrip line, which can avoid the additional loss caused by the special feeding network and simplify the production process of the antenna.

[0141] In some possible implementation manners, the part of at least one microstrip line in the N microstrip lines that is connected to the feeding structure includes a protrusion.

[0142] For example, in (a) of FIG. 11, the first end of the microstrip line connected to the first feeding structure includes a protrusion, which can also be referred to as an impedance matching stub. The impedance matching stub can improve the bandwidth of the antenna.

[0143] For example, in (b) of FIG. 11, the first end of the five microstrip lines connected to the five feeding structures all includes a protrusion.

[0144] Based on the scheme provided in the embodiments of the present application, the impedance matching stub provided on the microstrip line can improve the bandwidth of the antenna.

[0145] In some possible implementation manners, along the z-axis direction, the antenna can sequentially include a first metal layer, a first dielectric substrate, a second metal layer, a second dielectric substrate and a microstrip line. When the microstrip line is located below the second metal layer, the radiation of the microstrip line will not be reflected by the second metal layer, and the influence of the radiation of the microstrip line on the signal of the antenna radiation can be avoided.

[0146] In some possible implementation manners, the second metal layer includes N first through holes, the N first through holes correspond to the N feeding structures one by one, and the distance between the projection of each first through hole on the first metal layer and the geometric center of the projection of the feeding structure corresponding to each first through hole on the first metal layer is less than or equal to a second threshold.

[0147] It can be understood that, in order to enable the microstrip line to be connected to the feeding structure, the part of the second metal layer corresponding to the feeding structure includes the first through hole.

[0148] Based on the scheme provided in the embodiments of the present application, the distance between the through hole of the second metal layer and the projection of the corresponding feeding structure on the z-axis direction is less than or equal to the second threshold, and the value of the second threshold can be as small as possible, so that the symmetry of the antenna radiation in space is better.

[0149] In some possible implementation manners, the second metal layer includes a plurality of second through holes, the plurality of second through holes correspond to the ground structures one by one, and a distance between a projection of each second through hole on the first metal layer and a geometric center of a projection of each ground structure corresponding to the second through hole on the first metal layer is less than or equal to a fourth threshold value.

[0150] It can be understood that, in the antenna made of the medium substrate of different processes or materials, the second metal layer can have or not have a through hole at the position corresponding to the ground structure. When the medium substrate is a PCB board, in order to realize electrical connection between the second metal layer and the ground structure, the PCB board has a through hole at the position corresponding to the ground structure, and the second metal layer and the corresponding ground structure can be connected by metalization through the through hole. In addition, the fourth threshold value can be as small as possible, so that the radiation of the antenna is more symmetrical in space and is easy to process.

[0151] For example, as shown in FIG. 12, FIG. 12 is a schematic diagram of a projection of a second metal layer in a z-axis direction according to an embodiment of the present application. The part filled with oblique lines in FIG. 12 is the second metal layer, and the part not filled in FIG. 12 is a through hole. The feed structure can penetrate the second metal layer through part of the through holes and be connected with the microstrip line. The ground structure can be connected with the lower surface of the second medium substrate through part of the through holes (for example, the through hole where the ground structure is located can be connected to the second metal layer and extend to the lower surface of the second medium substrate where the microstrip line is located), which can avoid a blind hole (the through hole corresponding to the ground structure only penetrates the first medium substrate but does not penetrate the second medium substrate, which can be referred to as a blind hole) in the multi-layer PCB structure and simplify the processing process.

[0152] In some possible implementation manners, the second metal layer includes a fourth annular gap, and the fourth annular gap is located around the projection of the feed structure on the second metal layer.

[0153] For example, the size of the through hole corresponding to the part of the feed structure in the second metal layer is greater than the size of the projection of the feed structure on the second metal layer. For example, when the diameter of the circular through hole of the second metal layer is greater than the diameter of the projection of the corresponding feed structure on the second metal layer, the second metal layer and the feed structure can form a fourth annular gap in the plane where the second metal layer is located.

[0154] It can be understood that the fourth annular gap described above can be a regular polygonal gap or an irregularly shaped gap. The embodiments of the present application do not limit this.

[0155] It can be understood that the shape and position arrangement of the through hole in the second metal layer are only examples, and the through hole can be circular or regular polygonal. The shape and position arrangement of the through hole capable of enabling the second metal layer to satisfy circular rotational symmetry can be included in the embodiments of the present application, and the embodiments of the present application do not limit this.

[0156] It can be understood that the size of the through hole in the first metal layer / second metal layer is only an example, and the size can be designed according to actual engineering needs. For example, the size of the through hole corresponding to the feed structure can be greater than or equal to the size of the through hole corresponding to the ground structure, the size of the through hole corresponding to the first feed structure can be greater than the size of the through hole corresponding to the second feed structure, the size of the through hole in the first metal layer corresponding to the same feed structure can be equal to or greater than the size of the through hole in the second metal layer, the size of the through hole in the first metal layer corresponding to the same first ground structure can be greater than the size of the through hole in the second metal layer, and the size of the through hole in the first metal layer corresponding to the second ground structure can be equal to the size of the through hole in the second metal layer. The embodiments of the present application do not limit this.

[0157] In some possible implementation manners, along the z-axis direction, the antenna can sequentially include the first metal layer, the first dielectric substrate, the microstrip line, the second dielectric substrate, and the second metal layer.

[0158] It can be understood that when the microstrip line is located above the second metal layer, the part of the second metal layer corresponding to the feed structure can not include the through hole. For example, the second metal layer can be a metal layer without a through hole.

[0159] For example, the ground structure can be connected to the lower surface of the second dielectric substrate through part of the through holes shown in FIG. 12 (for example, the through hole where the ground structure is located can penetrate the first dielectric substrate and the second dielectric substrate, and extend to the lower surface of the second dielectric substrate).

[0160] It can be understood that the first dielectric substrate and / or the second dielectric substrate can be air, or a plate made of foam, epoxy glass cloth substrate, or ceramic material, and the first dielectric substrate and / or the second dielectric substrate can be a single-layer structure or a multi-layer structure. The embodiments of the present application do not limit this.

[0161] It can be understood that the first metal layer or the second metal layer can be obtained by using a chemical etching process, or the first metal layer or the second metal layer can be a metal pattern obtained by laser cutting a metal patch attached to the dielectric substrate, and the first metal layer or the second metal layer can also be a plate obtained by laser cutting a metal plate. The embodiments of the present application do not limit this.

[0162] It can be understood that the part of the first dielectric substrate corresponding to the feed structure / ground structure can have a via hole, and the part of the second dielectric substrate corresponding to the feed structure / ground structure can have a via hole. The size of the via hole in the first metal layer corresponding to the same feed structure can be greater than the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same feed structure; the size of the via hole in the second metal layer corresponding to the same feed structure can be greater than the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same feed structure; the size of the via hole in the first metal layer corresponding to the same first ground structure can be greater than the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same first ground structure; the size of the via hole in the second metal layer corresponding to the same first ground structure can be equal to the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same first ground structure; the size of the via hole in the first metal layer corresponding to the same second ground structure can be equal to the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same second ground structure; and the size of the via hole in the second metal layer corresponding to the same second ground structure can be equal to the size of the via hole in the first dielectric substrate / second dielectric substrate corresponding to the same second ground structure.

[0163] The antenna with the structure of the first metal layer shown in (b) of FIG. 6, the microstrip line shown in (b) of FIG. 11, and the second metal layer shown in FIG. 12 was tested, and the test results are shown in FIG. 13 and FIG. 14. FIG. 13 is a schematic diagram of the test results of an antenna provided by an embodiment of the present application. In order to test the S parameters of the antenna structure, port 5 is connected to a 50-ohm load, and antenna ports 1 to 4 are respectively connected to the test ports of a vector network analyzer. As shown in FIG. 13, the bandwidth of the antenna port can cover 10-10.5 GHz.

[0164] The radiation performance of each port of the antenna with the structure of the first metal layer shown in (b) of FIG. 6, the microstrip line shown in (b) of FIG. 11, and the second metal layer shown in FIG. 12 was tested in a darkroom environment. When only port 1 is excited and the other ports are connected to a 50-ohm load, the gain varies with frequency and is 2.8-3.2 dBi, and the efficiency varies with frequency and is 35%-42%. When only port 2 is excited and the other ports are connected to a 50-ohm load, the gain varies with frequency and is 5-6 dBi, and the efficiency varies with frequency and is 44%-51%. Since ports 2-5 satisfy circular symmetry, when only port 3 or port 4 or port 5 is excited and the other ports are connected to a 50-ohm load, the test results are similar to the test results when only port 2 is excited and the other ports are connected to a 50-ohm load.

[0165] In some possible implementation manners, when the antenna is used for communication at a frequency of 10 GHz, the distance between the first feeding structure and the second feeding structure is 5.1 mm.

[0166] Specifically, the first feeding structure and the second feeding structure are parallel to each other along the z-axis direction, and the distance between the projection of the first feeding structure on the first metal layer and the projection of the second feeding structure on the first metal layer is 5.1 mm.

[0167] FIG. 14 is a schematic diagram of test results of another antenna provided in embodiments of the present application. The first antenna and the second antenna are respectively used as a sending end and a receiving end, and are tested in a reverberation chamber. The first antenna and the second antenna both satisfy the antenna structure with the first metal layer shown in (b) of FIG. 6, the microstrip line shown in (b) of FIG. 11, and the second metal layer shown in FIG. 12, and both the first antenna and the second antenna are five-port antennas. By rotating the angle of the stirrer in the reverberation chamber, channel conditions with different multipaths can be obtained. During the test of the first antenna and the second antenna, a two-port vector network analyzer can be used to test channel responses. The first port of the two-port vector network analyzer (the first port can also be referred to as port 1 of the two-port vector network analyzer) can be connected to the input end of the first switch network, and the output end of the first switch network can be connected to ports 1-5 of the first antenna. The second port of the two-port vector network analyzer (the second port can also be referred to as port 2 of the two-port vector network analyzer) can be connected to the input end of the second switch network, and the output end of the second switch network can be connected to ports 1-5 of the second antenna. Under each channel condition, by switching the states of the two switch networks respectively, one output end of a corresponding switch network can be connected to the input end of the same switch network, and signals can be transmitted or received from the corresponding antenna port. By polling different switch states, 5*5=25 different channel responses can be obtained under each channel condition. Arranging the 25 channel responses forms a 5*5 channel matrix H, and the eigenvalues of the channel matrix can be obtained. The equivalent degree of freedom (EDOF) can be calculated according to the following formula. Wherein K is the number of ports, K=5, p is the signal to noise ratio (SNR), and sk is the kth normalized eigenvalue of the channel.

[0168] The curve of the calculated equivalent degrees of freedom versus the signal-to-noise ratio can be shown in FIG. 14, where the solid line is the equivalent degrees of freedom obtained according to the test results, and the curve is the equivalent degrees of freedom obtained assuming that the channel matrix is an ideal independent and identically distributed (i.i.d.) channel. It can be found that when the signal-to-noise ratio is high, the maximum equivalent degrees of freedom in both scenarios are equal to the number of ports, i.e., equal to 5. However, due to the influence of antenna port coupling, when the signal-to-noise ratio is less than 50 dB, the equivalent degrees of freedom of the test scenario are less than those of the ideal channel.

[0169] In some possible implementation manners, an antenna array can include at least two antennas in any of the above possible implementation manners, and when the antenna array is used for communication at an X GHz frequency, a distance between first feeding structures of two adjacent antennas in the antenna array is less than or equal to C / (2X), where C represents the speed of light.

[0170] Specifically, a plurality of antenna ports can form a subarray through a feeding network, each subarray is connected to one radio frequency channel, and a plurality of subarrays or antennas can form an antenna array, or each antenna port is connected to one radio frequency channel.

[0171] For example, as shown in FIG. 15, which is a schematic diagram of an antenna array provided in an embodiment of the present application. The antenna in any of the above possible implementation manners satisfies the condition that the size is less than or equal to (C / (2X)*C / (2X)), and the antenna can be used for two-dimensional arraying. FIG. 15 is a 5-antenna arraying structure, FIG. 15(a) is a schematic diagram of the front of the antenna arraying, and FIG. 15(b) is a schematic diagram of the back of the antenna arraying (the diagonally hatched part in FIG. 15(b) represents a microstrip line, and the arrangement and number of the microstrip lines are only examples and do not limit the embodiments of the present application), the first metal layer of the antenna in FIG. 15 satisfies that the length along the first direction is equal to C / (2X) and the length along the second direction is equal to C / (2X), and the first direction and the second direction are perpendicular. As shown in FIG. 15(a), the spacing between two adjacent antennas in the horizontal direction and the vertical direction is both C / (2X) (i.e., the distance between the first feeding structures of two adjacent antennas in the antenna array is equal to C / (2X)), and the periphery of the antenna can be connected to a connector structure, which is used to connect a grounded coplanar waveguide and a test instrument, provide an excitation signal or a test port. Due to the influence of the coupling of the surrounding units, the port gain and efficiency decrease. The maximum gain is 5dBi, and the maximum efficiency is 39%.

[0172] In some possible implementation manners, when a plurality of antennas form an antenna array, among the antennas forming the antenna array, two adjacent antennas can have a certain distance, for example, the edges of the first metal layers of the two adjacent antennas can not be connected.

[0173] When the plurality of antennas constitute an antenna array, due to the influence of the coupling of surrounding antennas, the sizes of the annular slots around different feed structures of different antennas are different, which can be debugged according to the frequency point and performance test of actual work to obtain the optimal size of the annular slot.

[0174] In some possible implementation manners, a base station comprises the antenna in any of the above possible implementation manners, and a radio frequency unit connected to the antenna.

[0175] In some possible implementation manners, a system comprises a base station composed of the antenna in any of the above possible implementation manners.

[0176] The above describes only a specific implementation manner of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An antenna, characterized by The antenna comprises: a radiator, the radiator comprises a first metal layer and N feed structures, the first metal layer and the N feed structures are coupled and connected; the first metal layer satisfies circular symmetry; the N feed structures correspond to N ports one by one, each feed structure is used for transmitting a signal to the radiator for the corresponding port, and N is an integer greater than or equal to 3; the N feed structures comprise one first feed structure and M second feed structures, M is an integer less than N and greater than 1; the projection of the first feed structure on the first metal layer is less than or equal to a first threshold value from the geometric center of the first metal layer; the M second feed structures surround the first feed structure, and the arrangement of the M second feed structures satisfies circular symmetry, and the N feed structures form a circularly symmetric structure.

2. The antenna according to claim 1, wherein N satisfies N=5, and M satisfies M=4.

3. The antenna according to claim 1 or 2, wherein when the antenna is used for communication at an X GHz frequency, the first metal layer satisfies at least one of the following conditions: A≤C / (2X); and / or, B≤C / (2X); wherein A represents the length of the first metal layer along a first direction, B represents the length of the first metal layer along a second direction, the plane formed by the first direction and the second direction is parallel to the first metal layer, and C represents the speed of light.

4. The antenna according to any one of claims 1-3, wherein, The antenna further comprises: a dielectric substrate, part or all of the N feed structures are located in the dielectric substrate; a second metal layer, the second metal layer satisfies circular symmetry, and the second metal layer and the N feed structures are coupled and connected; the dielectric substrate is located between the first metal layer and the second metal layer.

5. The antenna according to claim 4, wherein the antenna further comprises M first ground structures, the M first ground structures are coupled and connected with the first metal layer, and the M first ground structures are electrically connected with the second metal layer; and / or, the antenna further comprises M second ground structures, the M second ground structures are coupled and connected with the first metal layer, and the M second ground structures are electrically connected with the second metal layer.

6. The antenna according to any one of claims 1-5, wherein the first metal layer comprises a first annular slot, and the first annular slot is located around the projection of the first feed structure on the first metal layer; and / or, the first metal layer comprises a second annular slot, and the second annular slot is located around the projection of the second feed structure on the first metal layer.

7. The antenna according to claim 5, wherein the first metal layer comprises a third annular slot, and the third annular slot is located around the projection of the first ground structure on the first metal layer.

8. The antenna according to any one of claims 1-7, wherein the antenna further comprises N microstrip lines, and each microstrip line is used for transmitting a signal to the corresponding feed structure.

9. The antenna of claim 4 or 5, wherein, the second metal layer comprises N first through holes, the N first through holes correspond to the N feed structures one by one, and a distance between a projection of each first through hole on the first metal layer and a geometric center of a projection of each first through hole corresponding feed structure on the first metal layer is less than or equal to a second threshold value.

10. The antenna of claim 8, wherein, a part of at least one of the N microstrip lines connected with the feed structure comprises a convex part.

11. The antenna of any one of claims 1-10, wherein, when the antenna is used for communication at a frequency of 10 GHz, a distance between the first feed structure and the second feed structure is 5.1 mm.

12. An antenna array, characterized by comprising: at least two antennas as claimed in any one of claims 1-11, when the antenna array is used for communication at a frequency of X GHz, a distance between the first feed structures of two adjacent antennas in the antenna array is less than or equal to C / (2X), C representing the speed of light.

13. A base station, characterized by comprising: an antenna as claimed in any one of claims 1-11, and a radio frequency unit connected with the antenna.

14. A system, characterized by comprising at least one base station as claimed in claim 13.

15. A chip, characterized by for implementing a feed structure as claimed in any one of claims 1-11.

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