Frequency selection apparatus, base station antenna, and base station device

Abstract

Disclosed in embodiments of the present application are a frequency selection apparatus, a base station antenna, and a base station device. The frequency selection apparatus comprises multiple metal shells, at least one metal connecting plate, and at least one FSS unit. The multiple metal shells are distributed in a first direction, every two adjacent metal shells are electrically connected by means of a corresponding metal connecting plate, each metal connecting plate comprises a slot structure, and the slot structure of each metal connecting plate is used for insertion of the at least one FSS unit. The frequency selection apparatus can transmit electromagnetic waves in some of frequency bands and reflect electromagnetic waves in the remaining frequency bands, thus having a frequency selection function. In addition, use of the frequency selection apparatus designed in the present application is conducive to improving the transmittance of electromagnetic waves in some of the frequency bands and the reflectance of electromagnetic waves in the remaining frequency bands, and can better utilize the performance of an antenna array in each frequency band.

Description

Frequency selection device, base station antenna and base station equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on March 18, 2024, with application number 202410313445.9 and invention name “A frequency selection device, base station antenna and base station equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a frequency selection device, a base station antenna, and a base station device. Background Art

[0003] With the continuous development of 5G technology, spectrum diversification has become an inevitable trend. Active and passive base station antennas can effectively implement daily communications in different spectrums, but they face high pole rental costs. A fusion design of active and passive antennas can alleviate this problem.

[0004] In a multi-band antenna system that integrates active and passive antennas, antenna arrays for different operating frequency bands can be stacked. Currently, there is an urgent need for a design method that can ensure that antenna arrays for each operating frequency band can perform well. Summary of the Invention

[0005] The embodiments of the present application provide a frequency selection device, a base station antenna, and base station equipment. This frequency selection device can transmit electromagnetic waves in certain frequency bands and reflect electromagnetic waves in other frequency bands, thereby providing frequency selection functionality. Furthermore, the frequency selection device designed in this application can improve the transmittance of electromagnetic waves in certain frequency bands and the reflectivity of electromagnetic waves in other frequency bands, thereby enhancing the performance of antenna arrays in each frequency band.

[0006] In a first aspect, embodiments of the present application provide a frequency selection device. The frequency selection device includes multiple metal housings, at least one metal connecting plate, and at least one frequency selective surface (FSS) unit. The multiple metal housings are distributed along a first direction, and each adjacent metal housing is electrically connected via a metal connecting plate. Each metal connecting plate includes a slot structure, and the slot structure of each metal connecting plate is used to plug in at least one FSS unit.

[0007] Among them, the FSS unit is essentially a spatial filter, which exhibits obvious bandpass or bandstop filtering characteristics when interacting with electromagnetic waves, achieving the transmission of electromagnetic waves in some frequency bands and reflecting electromagnetic waves in other frequency bands, thereby having a frequency selection function. In one possible scenario, the frequency selection device is located between the antenna array of frequency band 1 and the antenna array of frequency band 2. The design method of connecting the metal shell and the metal connecting plate in the frequency selection device realizes a function similar to a reflector, which is used to reflect the signal emitted by the antenna array of frequency band 1, which is beneficial to enhancing the signal of frequency band 1. In addition, the design method of plugging the FSS unit into the slot structure on the metal connecting plate realizes the guidance of the signal emitted by the antenna array of frequency band 2, that is, the signal of frequency band 2 can be transmitted through the FSS unit. Among them, the slot structure provided on the metal connecting plate is not only used for plugging the FSS unit, but also helps to improve the transmittance of electromagnetic waves in some frequency bands and the reflectivity of electromagnetic waves in another frequency band. Therefore, the frequency selection device provided in the embodiment of the present application can better exert the performance of the antenna arrays of each frequency band.

[0008] In some possible embodiments, the FSS unit includes a first substrate and a second substrate. The slot structure of each metal connecting plate includes a first slot region and a second slot region. The first slot region is used to connect to the first substrate, and the second slot region is used to connect to the second substrate. It should be understood that the number of substrates included in the FSS unit depends on the polarization type of the antenna. If an antenna with two polarization directions is used, the FSS unit should include a first substrate and a second substrate. This helps ensure that the frequency selective device has good transmittance for signals of different polarizations within the specified frequency band.

[0009] In some possible implementations, the first substrate and the second substrate are placed crosswise to better accommodate antennas with two different polarization directions.

[0010] In some possible implementations, if the signals in a specified frequency band include electromagnetic waves with transverse magnetic (TM) polarization and electromagnetic waves with transverse electric (TE) polarization, the first and second substrates can be designed to be positioned perpendicular to each other. The first substrate is parallel to the first direction, the second substrate is parallel to the second direction, and the first and second directions are perpendicular. In this way, the first and second substrates are used to guide TM and TE polarization, respectively, thereby achieving good transmittance for both TM and TE polarizations.

[0011] In some possible embodiments, the first substrate and the second substrate are placed perpendicular to each other, and the first substrate forms an angle of 45° with the first direction and the second direction, respectively, and the second substrate forms an angle of 45° with the first direction and the second direction, respectively, so that the first substrate and the second substrate are respectively used to guide ±45° polarized electromagnetic waves in a specified frequency band, enriching the application scenarios of this solution.

[0012] In some possible embodiments, the first gap area and the second gap area do not overlap, that is, the first gap area and the second gap area are not connected. Such a design is conducive to improving the transmittance of electromagnetic waves in some frequency bands and the reflectivity of electromagnetic waves in another frequency band.

[0013] In some possible implementations, each metal connecting plate is parallel to the first direction, each FSS unit is plugged into the corresponding slot structure along the third direction, and the first direction is perpendicular to the third direction, which is beneficial to improving the overall structural stability of the frequency selection device.

[0014] In some possible implementations, the surface of each FSS unit includes a metal pattern, comprising a first metal structure extending along a third direction and a second metal structure extending perpendicular to the third direction. It should be understood that the second metal structure facilitates the reception and transmission of signals at a specified frequency, while the first metal structure facilitates the transmission of signals at the specified frequency along the third direction, thereby ensuring that signals at the specified frequency incident on the frequency selection device can pass smoothly and be transmitted.

[0015] In some possible embodiments, the metal pattern further includes a third metal structure extending along a third direction, and the first metal structure and the third metal structure are coupled to each other. In other words, a gap may be provided between the first metal structure and the third metal structure, for example, in a "Z" shape, to improve signal transmission.

[0016] In some possible embodiments, each pair of adjacent metal shells is physically connected to a metal connecting plate between them, thereby improving the stability of the overall structure. For example, the metal shells and the metal connecting plate may be integrated. In another example, the metal shells and the metal connecting plate may be physically connected by splicing or welding.

[0017] In some possible implementations, each pair of adjacent metal shells is coupled to a metal connecting plate between them, expanding the implementation of this solution. For example, while the metal shells and the metal connecting plate have no direct physical contact, electrical signals can be transmitted from the metal shells to the metal connecting plate via coupling, and the metal shells and the metal connecting plate can be secured together by a non-metallic structure.

[0018] In some possible implementations, the frequency selection device further includes a signal transmission component, and at least one metal housing is used to house the signal transmission component. It should be understood that the metal housing provides space for accommodating other antenna structures, such as signal transmission lines, thereby rationally utilizing space, reducing the overall antenna structure footprint, and facilitating a miniaturized design.

[0019] In some possible implementations, the signal transmission device includes a packaging shell, and at least one metal shell is used to accommodate the packaging shell.

[0020] In some possible implementations, a signal transmission device is used to connect to an antenna element in at least one operating frequency band. For example, the antenna element's feed port is connected to the signal transmission device, and the antenna element's ground port is connected to the metal housing. In other words, the structure of the frequency selection device provided in the embodiments of the present application can also effectively accommodate the arrangement of the antenna elements.

[0021] In some possible embodiments, the multiple metal shells are distributed at equal intervals, and each pair of adjacent antenna elements operating in the same frequency band is connected to a signal transmission device located within each metal shell. The distance between each pair of adjacent antenna elements operating in the same frequency band is an integer multiple of the distance between each pair of adjacent metal shells. It should be understood that the distribution period of antenna elements in different frequency bands may vary. To facilitate the arrangement of antenna elements in each frequency band, a targeted design can be implemented so that the arrangement of the metal shells takes into account the arrangement of the antenna elements.

[0022] In a second aspect, an embodiment of the present application provides a base station antenna. The base station antenna includes: an antenna array and a frequency selection device as described in any embodiment of the first aspect, wherein the antenna array is used for signal transmission and reception, and the frequency selection device is used for filtering.

[0023] In some possible embodiments, the antenna array includes a first antenna array and a second antenna array, and the frequency selection device is located between the first antenna array and the second antenna array. The frequency selection device is used to reflect signals of a first frequency band transmitted by the first antenna array and transmit signals of a second frequency band transmitted by the second antenna array.

[0024] In the third aspect, an embodiment of the present application provides a base station device, which includes: a radio frequency module and a base station antenna as described in any embodiment of the second aspect, the radio frequency module is used to convert a baseband signal into a high-frequency signal and send it to the base station antenna, and convert the high-frequency signal from the base station antenna into a baseband signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic diagram of an application scenario of an embodiment of the present application;

[0026] FIG2 is a schematic diagram of a possible structure of a base station device in an embodiment of the present application;

[0027] FIG3 is a schematic diagram of a possible structure of a base station antenna in an embodiment of the present application;

[0028] FIG4 is a schematic diagram of a three-dimensional structure of a frequency selection device in an embodiment of the present application;

[0029] FIG5 is a side view of a planar structure of a frequency selection device according to an embodiment of the present application;

[0030] FIG6 is a side view of another planar structure of the frequency selection device according to an embodiment of the present application;

[0031] FIG7 is another schematic diagram of the three-dimensional structure of the frequency selection device in an embodiment of the present application;

[0032] FIG8 is a side view of another planar structure of the frequency selection device according to an embodiment of the present application;

[0033] FIG9 is a schematic diagram of a partial three-dimensional structure of a frequency selection device in an embodiment of the present application;

[0034] FIG10 is a top view of a metal connecting plate according to an embodiment of the present application;

[0035] FIG11 is a partial top view of a frequency selection device according to an embodiment of the present application;

[0036] FIG12 is a schematic structural diagram of a first substrate in an embodiment of the present application;

[0037] FIG13 is a schematic structural diagram of a second substrate in an embodiment of the present application;

[0038] FIG14 is a schematic diagram showing the filtering effect of the frequency selection device on TE polarized electromagnetic waves in an embodiment of the present application;

[0039] FIG15 is a schematic diagram showing the filtering effect of the frequency selection device on TM polarized electromagnetic waves in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The embodiments of the present application provide a frequency selection device, a base station antenna, and base station equipment. This frequency selection device can transmit electromagnetic waves in certain frequency bands and reflect electromagnetic waves in other frequency bands, thereby providing frequency selection functionality. Furthermore, the frequency selection device designed in this application can improve the transmittance of electromagnetic waves in certain frequency bands and the reflectivity of electromagnetic waves in other frequency bands, thereby enhancing the performance of antenna arrays in each frequency band.

[0041] It should be noted that the terms "first", "second", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] To facilitate understanding, the technical terms involved in the embodiments of the present application are first explained below.

[0043] Base Station Antenna (BSA): A type of antenna used by telecom operators to transmit and receive signals to mobile phones, etc. It is usually installed on the top of a tower or on the roof of a building. A base station antenna usually consists of an antenna array, a reflector, and a feed network.

[0044] Antenna array: an array structure composed of multiple antenna elements arranged together.

[0045] Reflector: A metal plate used to support the antenna array and feed structure. It is the main structure of the antenna and will have an electrical impact on the antenna.

[0046] Feed Network: A network structure used to transmit signals to the antenna array. The structure can be a cavity or a coaxial cable. The feed network may include an external conductor.

[0047] Frequency Selective Surfaces (FSS): A two-dimensional periodic array structure. Essentially a spatial filter, FSS exhibits distinct bandpass or bandstop filtering characteristics when interacting with electromagnetic waves. Due to their unique frequency-selective properties, FSSs are widely used in the microwave, infrared, and visible light bands.

[0048] Figure 1 is a schematic diagram of an application scenario of an embodiment of the present application. As shown in Figure 1, the application scenario may include a base station and a terminal. Wireless communication can be achieved between the base station and the terminal. The base station can be located in a base station subsystem (BBS), a UMTS terrestrial radio access network (UTRAN), or an evolved universal terrestrial radio access network (E-UTRAN), and is used to provide cell coverage for wireless signals to enable communication between terminal devices and the wireless network. Specifically, the base station can be a base transceiver station (BTS) in a global system for mobile communications (GSM) or a (code division multiple access, CDMA) system, or a node B (NB) in a wideband code division multiple access (WCDMA) system, or an evolutionary node B (eNB or eNodeB) in a long term evolution (LTE) system, or a wireless controller in a cloud radio access network (CRAN) scenario. Alternatively, the base station can also be a relay station, an access point, a vehicle-mounted device, a wearable device, a g-node (gNodeB or gNB) in a new radio (NR) system, or a base station in a future evolved network, etc., and the embodiments of the present application are not limited thereto.

[0049] Figure 2 is a schematic diagram of a possible structure of base station equipment in an embodiment of the present application. As shown in Figure 2, the base station equipment includes a base station antenna 1, a mast 2, an antenna adjustment bracket 3, and other structures. The base station antenna 1 may include a radome. The radome has excellent electrical properties for electromagnetic wave penetration and mechanical properties that can withstand harsh external environments, thereby protecting the base station antenna 1 from external environmental influences. The base station antenna 1 can be mounted on a mast 2 or a tower using the antenna adjustment bracket 3, allowing the base station antenna 1 to receive or transmit signals.

[0050] In addition, the base station device may also include a radio frequency processing unit 4 and a baseband processing unit 5. For example, the radio frequency processing unit 4 may be used to perform frequency selection, amplification, and down-conversion processing on the signal received by the base station antenna 1, and convert it into an intermediate frequency signal or a baseband signal and send it to the baseband processing unit 5, or the radio frequency processing unit 4 may be used to convert the baseband signal or intermediate frequency signal from the baseband processing unit 5 into an electromagnetic wave through the base station antenna 1 after up-conversion and amplification processing and send it out. The baseband processing unit 5 can be connected to the feeding network of the base station antenna 1 through the radio frequency processing unit 4. In some embodiments, the radio frequency processing unit 4 may also be referred to as a remote radio unit (RRU), and the baseband processing unit 5 may also be referred to as a baseband unit (BBU).

[0051] In one possible implementation, as shown in Figure 2 , the RF processing unit 4 can be integrated into the base station antenna 1, and the baseband processing unit 5 is located at a remote end of the base station antenna 1, with the RF processing unit 4 and the baseband processing unit 5 connected via a cable. In another possible implementation, both the RF processing unit 4 and the baseband processing unit 5 are located at a remote end of the base station antenna 1.

[0052] Figure 3 is a schematic diagram of a possible structure of a base station antenna in an embodiment of the present application. As shown in Figure 3, the antenna array of frequency band 1 and the antenna array of frequency band 2 are stacked on a reflector, and a frequency selection device is provided between the antenna array of frequency band 1 and the antenna array of frequency band 2. In one possible embodiment, the base station antenna structure shown in Figure 3 can be regarded as an active antenna and a passive antenna integrated (A+P) device. For example, the antenna array of frequency band 1 is a passive antenna array, which can be a fourth generation (4G) low-frequency antenna, generally in the 690MHz to 960MHz frequency band. For another example, the antenna array of frequency band 2 is an active antenna array, which can be a fifth generation (5G) high-frequency antenna, generally in the 2600MHz or 3500MHz frequency band, and the antenna array of frequency band 2 can be a massive multiple-input multiple-output (MM) antenna.

[0053] Specifically, the reflector is used to reflect the signal of the antenna array of frequency band 2, which plays a role in signal enhancement. The frequency selection device provided in the embodiment of the present application is used to reflect the signal of the antenna array of frequency band 1, while the signal of the antenna array of frequency band 2 can be transmitted through the frequency selection device. In other words, the frequency selection device has a filtering function. For the antenna array of frequency band 1, the frequency selection device is equivalent to a reflector, and for the antenna array of frequency band 2, the frequency selection device will not block the signal of frequency band 2. It should be understood that the signal of the antenna array of frequency band 1 includes the signal transmitted and received by the antenna array of frequency band 1, and the signal of the antenna array of frequency band 2 includes the signal transmitted and received by the antenna array of frequency band 2. The frequency selection device provided in the embodiment of the present application is introduced in detail below.

[0054] FIG4 is a schematic diagram of a three-dimensional structure of a frequency selection device in an embodiment of the present application. As shown in FIG4 , the frequency selection device includes: a plurality of metal shells 10, at least one metal connecting plate 20, and at least one frequency selective surface FSS unit 30. For ease of introduction, the three-dimensional directions in the embodiment of the present application are respectively recorded as the first direction, the second direction, and the third direction, that is, the first direction, the second direction, and the third direction are perpendicular to each other. Among them, the plurality of metal shells 10 are distributed along the first direction, and each adjacent two metal shells 10 are electrically connected through the metal connecting plate 20, that is, the electrical signal can be transmitted from one metal shell to another adjacent metal shell through the metal connecting plate. Each metal connecting plate 20 includes a slot structure, and the slot structure is used to plug the FSS unit 30, that is, the FSS unit 30 is plugged into the slot structure of the metal connecting plate 20 to achieve position fixation. Optionally, the metal connecting plate 20 is connected to the metal shell 10 in the middle position in the third direction, so that the two adjacent metal shells and the metal connecting plate in the middle form a structure similar to the Great Wall plate.

[0055] It should be understood that the present application does not limit the specific number of metal shells 10, metal connecting plates 20, and FSS units 30. Every two adjacent metal shells 10 should be equipped with one metal connecting plate 20, and each metal connecting plate 20 should be equipped with one FSS unit 30. It should also be understood that the metal shell 10 can be made entirely of metal material, or it can be formed by plating a layer of metal on the surface of a non-metallic material to form the metal shell 10. Similarly, the metal connecting plate 20 can be made entirely of metal material, or it can be formed by plating a layer of metal on the surface of a non-metallic material to form the metal connecting plate 20. The present application does not limit the outer contour shape of the metal shell 10 and the metal connecting plate 20, which can be a flat shape or a curved shape, etc.

[0056] It should be noted that, taking the frequency selection device shown in FIG4 as an example of the application of the scenario in FIG3 above, the design method of connecting the metal shell 10 and the metal connecting plate 20 in the frequency selection device realizes a function similar to a reflector, which is used to reflect the signal transmitted by the antenna array of frequency band 1, which is conducive to enhancing the signal of frequency band 1. In addition, the design method of plugging the FSS unit 30 in the slot structure on the metal connecting plate 20 realizes the guidance of the signal transmitted by the antenna array of frequency band 2, that is, the signal of frequency band 2 can be transmitted through the FSS unit 30. It should be understood that the slot structure provided on the metal connecting plate 20 is not only used for plugging the FSS unit 30, but also helps to improve the transmittance of electromagnetic waves in some frequency bands and the reflectivity of electromagnetic waves in other frequency bands. In other words, compared with the solution of placing only the FSS unit without placing the metal connecting plate between the metal shells, the frequency selection device provided in the present application can better exert the performance of the antenna arrays of each frequency band. In addition, the frequency selection device provided in the embodiment of the present application can make the signals of frequency band 2 with different incident angles have good transmittance, and can make the signals of frequency band 2 with different polarizations have good transmittance.

[0057] FIG5 is a side view of a planar structure of a frequency selection device in an embodiment of the present application. In one possible embodiment, the metal shell 10 and the metal connecting plate 20 are electrically connected by physical connection. For example, the metal shell 10 and the metal connecting plate 20 are designed as an integrated whole. In another example, the metal shell 10 and the metal connecting plate 20 are physically connected by splicing or welding. In another possible embodiment, the metal shell 10 and the metal connecting plate 20 are electrically connected by coupling. For example, as shown in FIG5 , the metal shell 10 and the metal connecting plate 20 have no direct physical contact, and the electrical signal can be transmitted from the metal shell 10 to the metal connecting plate 20 by coupling. The metal shell 10 and the metal connecting plate 20 can be fixed together by a non-metallic structure 50. For example, the metal shell 10 and the metal connecting plate 20 can be fixed by gluing. In another example, a support portion can extend from the metal shell 10, the surface of the support portion is provided with a non-metallic medium, and the metal connecting plate 20 is placed on the non-metallic medium.

[0058] In some possible scenarios, as shown in FIG4 or FIG5, the metal shell 10 is also used to accommodate a signal transmission device 40, wherein the signal transmission device 40 can also be regarded as a feed network. It should be understood that the metal shell provides space for accommodating other antenna structures such as signal transmission lines, so as to make rational use of space, reduce the space occupied by the overall structure of the antenna, and facilitate miniaturization. In practical applications, the internal space of the same metal shell 10 can be further divided into cavities, and different parts of the signal transmission device 40 can be placed in different cavities inside the same metal shell 10, for example, for realizing feed networks with different polarizations. Specifically, taking FIG5 as an example, the upper and lower cavities can be used, or the left and right cavities can be used, and the specific details are not limited here.

[0059] As an example, the signal transmission device 40 may include a phase shifter to change the maximum direction of antenna signal radiation. The signal transmission device 40 may also be provided with some modules for expanding performance, such as a combiner, which can be used to combine signals of different frequencies into one path and transmit them through the antenna array; or when used in reverse, it can be used to divide the signal received by the antenna array into multiple paths according to different frequencies and transmit them to the baseband processing unit for processing. For another example, the signal transmission device 40 may also include a filter to filter out interference signals. As an example, the signal transmission device 40 usually includes a packaging shell itself, that is, the signal transmission device 40 including the packaging shell is placed in the internal space of the metal shell 10. As another example, the packaging shell of the signal transmission device 40 itself can also be used as the metal shell 10, and the packaging shell of the signal transmission device 40 itself can be directly processed with the metal connecting plate 20 to achieve electrical connection between the two, without the need to additionally design the metal shell 10 as shown in Figures 4 or 5.

[0060] FIG6 is a side view of another planar structure of the frequency selection device in an embodiment of the present application. In one possible embodiment, not every metal housing 10 needs to be provided with a signal transmission device 40. The specific configuration can be flexibly selected based on actual needs. For example, as shown in FIG6 , some metal housings 10 are provided with a signal transmission device 40, while others are not.

[0061] FIG7 is a schematic diagram of another three-dimensional structure of a frequency selection device in an embodiment of the present application. Unlike the frequency selection devices shown in FIG4 to FIG6 above, in some possible scenarios, the metal housing 10 of the frequency selection device may also adopt a solid structure as shown in FIG7. This solid structure does not provide an internal space for accommodating the signal transmission device 40. For example, the solid structure may be entirely made of metal, or the solid structure may include non-metallic materials and be plated with metal on the outer layer. Regardless of the design, the solid structure includes at least an outer layer of metal, and naturally, the metal housing may also be used.

[0062] FIG8 is another side view of the planar structure of the frequency selection device in the embodiment of the present application. Each signal transmission device 40 is used to connect the antenna element of at least one working frequency band. For example, the feed port of the antenna element is connected to the signal transmission device 40, and the ground port of the antenna element is connected to the metal shell 10. As an example, the antenna array of frequency band 1 in the application scenario shown in FIG3 can be connected to the signal transmission device 40 in the manner shown in FIG8. Generally, the lower the working frequency of the antenna element, the larger the spacing required for the distribution of the antenna element. The period of the distribution of antenna elements in different frequency bands may be different. In order to facilitate the arrangement of antenna elements in each frequency band, a targeted design can be made so that the arrangement of the metal shell can take into account the arrangement of the antenna elements.

[0063] In some possible scenarios, as shown in FIG8 , the signal transmission device 40 within a portion of the metal housing 10 is used to connect the antenna element for frequency band 2 and the antenna element for frequency band 3, while the signal transmission device 40 within another portion of the metal housing 10 is used to connect the antenna element for frequency band 1 and the antenna element for frequency band 3. Multiple metal housings 10 are distributed at equal intervals, and the distance between each pair of adjacent antenna elements operating in the same frequency band is an integer multiple of the distance between each pair of adjacent metal housings. For example, the distance between each pair of adjacent antenna elements for frequency band 3 is equal to the distance between each pair of adjacent metal housings. For another example, the distance between each pair of adjacent antenna elements for frequency band 2 is twice the distance between each pair of adjacent metal housings. For another example, the distance between each pair of adjacent antenna elements for frequency band 1 is twice the distance between each pair of adjacent metal housings. In other possible scenarios, the antenna elements may be distributed at unequal intervals, and accordingly, the metal housings 10 may also be distributed at unequal intervals.

[0064] It should be understood that FIG8 shows a scenario in which the signal transmission device 40 within each metal housing 10 is connected to multiple antenna elements of different frequency bands, i.e., a scenario in which the antenna elements are placed at different frequencies. In other possible scenarios, the signal transmission device 40 within each metal housing 10 may also be connected to multiple antenna elements of the same frequency band, i.e., a scenario in which the antenna elements are placed at the same frequency.

[0065] Figure 9 is a schematic diagram of a partial three-dimensional structure of a frequency selection device in an embodiment of the present application. Figure 10 is a top view of a metal connecting plate in an embodiment of the present application. In one possible embodiment, as shown in Figure 9, the FSS unit 30 includes a first substrate 301 and a second substrate 302, which are arranged crosswise. Optionally, the first substrate 301 and the second substrate 302 may be a printed circuit board (PCB). For example, the first substrate 301 and the second substrate 302 may specifically adopt a metamaterial structure including a metal pattern on the surface, and the metal pattern may be attached to a dielectric plate such as polyethylene glycol terephthalate (PET) or polycarbonate (PC). As shown in Figure 10, the slot structure of the metal connecting plate 20 includes a first slot region 201 and a second slot region 202. The first slot region 201 is used for plugging into the first substrate 301, and the second slot region 202 is used for plugging into the second substrate 302. Specifically, the metal connecting plate 20 is parallel to the plane containing the first and second directions, and each substrate in the FSS unit 30 is vertically connected to the corresponding slot region on the metal connecting plate 20 along the third direction. Optionally, as shown in FIG10 , the first slot region 201 and the second slot region 202 do not overlap, that is, the first slot region 201 and the second slot region 202 are disconnected. This design is conducive to improving the transmittance of electromagnetic waves in some frequency bands and the reflectivity of electromagnetic waves in other frequency bands.

[0066] It should be understood that the number of substrates included in the FSS unit 30 depends on the polarization type of the antenna, which is subject to actual application and is not limited here. For example, if a dual-polarization antenna is used, the FSS unit 30 includes a first substrate 301 and a second substrate 302 as shown in the above embodiment. For another example, if a single-polarization antenna is used, the FSS unit 30 includes only one substrate. Accordingly, a slot area is provided on the metal connecting plate 20 for inserting the substrate.

[0067] In one possible scenario, as shown in Figure 9, a first substrate 301 and a second substrate 302 are placed perpendicular to each other, with the first substrate 301 parallel to a first direction and the second substrate 302 parallel to a second direction. For example, the first substrate 301 is used to guide electromagnetic waves with transverse magnetic (TM) polarization within a specified frequency band, and the second substrate 302 is used to guide electromagnetic waves with transverse electric (TE) polarization within a specified frequency band.

[0068] Figure 11 is a partial top view of a frequency selection device according to an embodiment of the present application. In another possible scenario, as shown in Figure 11, the first substrate 301 forms a 45° angle with the first direction and the second direction, respectively, and the second substrate 302 forms a 45° angle with the first direction and the second direction, respectively, so that the first substrate 301 and the second substrate 302 are respectively used to guide ±45° polarized electromagnetic waves in a specified frequency band.

[0069] It should be noted that the metal pattern on any substrate in the FSS unit 30 must be capable of receiving, transmitting, and transmitting signals in a specified frequency band, thereby enabling signals in the specified frequency band to be transmitted through the FSS unit 30 and achieving frequency selection. Several possible metal pattern designs for the substrate are described below. It should be understood that these are merely examples, and those skilled in the art can flexibly modify these patterns to achieve frequency selection based on actual needs. These examples are not listed here.

[0070] Figure 12 is a schematic structural diagram of the first substrate in an embodiment of the present application. As shown in Figure 12, the first substrate 301 includes a metal pattern composed of multiple metal structures. Taking the scenario shown in Figure 3 as an example, the antenna array of frequency band 2 sends the signal of frequency band 2 to the frequency selection device. The metal structure 301a is used to receive the signal of frequency band 2 and transmit the signal of frequency band 2 to the metal structure 301d through the metal structure 301b and the metal structure 301c. The metal structure 301d then transmits the signal of frequency band 2, thereby achieving the effect that the signal of frequency band 2 can be sent out through the frequency selection device. Among them, the metal structure 301a and the metal structure 301d are metal structures extending along the first direction, which are conducive to the reception and transmission of signals. The metal structure 301b and the metal structure 301c include metal structures extending along the third direction, which are conducive to the transmission of signals along the third direction. In the embodiment shown in Figure 12, the metal structure 301b can be referred to as the first metal structure, the metal structure 301a and the metal structure 301d can be referred to as the second metal structure, and the metal structure 301c can be referred to as the third metal structure. It should be understood that to match the resonant frequency of the antenna array design for frequency band 2, a gap may be provided between metal structure 301b and metal structure 301c, that is, metal structure 301b and metal structure 301c are coupled. For example, the gap between metal structure 301b and metal structure 301c may be arranged in a "Z" shape to improve signal transmission. Optionally, the metal pattern on the first substrate 301 may further include a metal structure 301e shaped like an "I" to facilitate compensating for phase differences between signals of different polarizations.

[0071] As another example, based on the structure shown in FIG12 , metal structure 301b and metal structure 301c can be physically connected, i.e., no gap is provided between metal structure 301b and metal structure 301c. As another example, based on the structure shown in FIG12 , the "C"-shaped structure formed by metal structure 301b and metal structure 301c can be adjusted to form a "U"-shaped structure formed by metal structure 301b and metal structure 301c.

[0072] FIG13 is a schematic diagram of the structure of the second substrate in an embodiment of the present application. As shown in FIG13 , the second substrate 302 includes a metal pattern composed of multiple metal structures. Taking the scenario shown in FIG3 as an example, the antenna array of frequency band 2 sends the signal of frequency band 2 to the frequency selection device. The metal structure 302a is used to receive the signal of frequency band 2 and transmit the signal of frequency band 2 to the metal structure 302d through the metal structure 302b and the metal structure 302c. The metal structure 302d then transmits the signal of frequency band 2, thereby achieving the effect that the signal of frequency band 2 can be transmitted through the frequency selection device. Among them, the metal structure 302a and the metal structure 302d are metal structures extending along the second direction, which is conducive to the reception and transmission of signals. The metal structure 302b and the metal structure 302c include metal structures extending along the third direction, which is conducive to the transmission of signals along the third direction. In the embodiment shown in FIG13 , the metal structure 302b can be referred to as the first metal structure, the metal structure 302a and the metal structure 302d can be referred to as the second metal structure, and the metal structure 302c can be referred to as the third metal structure. It should be understood that to match the resonant frequency of the antenna array design for frequency band 2, a gap may be provided between metal structure 302b and metal structure 302c, that is, metal structure 302b and metal structure 302c are coupled. For example, the gap between metal structure 302b and metal structure 302c may be arranged in a "Z" shape, which facilitates improved signal transmission. Optionally, as shown in FIG13 , metal structures symmetrical to metal structures 302a, 302b, 302c, and 302d may be provided on second substrate 302.

[0073] As another example, based on the structure shown in FIG13 , metal structure 302b and metal structure 302c can be physically connected, i.e., no gap is provided between metal structure 302b and metal structure 302c. As another example, based on the structure shown in FIG13 , the "C"-shaped structure formed by metal structure 302b and metal structure 302c can be adjusted to form a "U"-shaped structure formed by metal structure 302b and metal structure 302c.

[0074] FIG14 is a schematic diagram of the filtering effect of the frequency selection device on TE polarized electromagnetic waves in an embodiment of the present application. FIG15 is a schematic diagram of the filtering effect of the frequency selection device on TM polarized electromagnetic waves in an embodiment of the present application. As shown in FIG14 and FIG15, the horizontal axis represents the frequency (unit: GHz), and the vertical axis represents the transmission coefficient (unit: dB). FIG14 shows the transmission coefficient of TE polarized electromagnetic waves as a function of frequency, and FIG15 shows the transmission coefficient of TM polarized electromagnetic waves as a function of frequency. For example, a transmission coefficient of 0 dB can indicate that the electromagnetic wave can completely pass through the frequency selection device, and a transmission coefficient less than -20 dB can indicate that the electromagnetic wave basically cannot pass through the frequency selection device. In addition, FIG14 and FIG15 also show the filtering effect of the frequency selection device on electromagnetic waves at different incident angles, wherein an incident angle of 0° indicates that the electromagnetic wave enters the frequency selection device along the third direction mentioned above. As can be seen from FIG14 and FIG15, for electromagnetic waves with a frequency greater than 3 GHz, whether TE polarization or TM polarization, and regardless of the incident angle, can pass through the frequency selection device well. That is to say, taking Figures 14 and 15 as an example, the frequency selection device provided in the embodiment of the present application has a good transmittance for electromagnetic waves greater than 3 GHz and a good reflectivity for electromagnetic waves less than 3 GHz.

[0075] As described above, the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of this application. In the absence of conflict, the embodiments of this application and the features therein can be combined with each other.

Claims

1. A frequency selection device, characterized in that: include: A plurality of metal shells, at least one metal connecting plate and at least one frequency selective surface (FSS) unit; The plurality of metal shells are distributed along a first direction, and every two adjacent metal shells are electrically connected via the metal connecting plate. Each metal connecting plate includes a slot structure, and the slot structure of each metal connecting plate is used to plug in the FSS unit.

2. The frequency selection device according to claim 1, wherein The FSS unit includes a first substrate and a second substrate. The gap structure of each metal connecting plate includes a first gap area and a second gap area. The first gap area is used to plug the first substrate, and the second gap area is used to plug the second substrate.

3. The frequency selection device according to claim 2, characterized in that The first substrate and the second substrate are placed crosswise to each other.

4. The frequency selection device according to claim 2, wherein: The first substrate and the second substrate are placed perpendicular to each other.

5. The frequency selection device according to claim 4, characterized in that The first substrate is parallel to the first direction, the second substrate is parallel to the second direction, and the first direction is perpendicular to the second direction.

6. The frequency selection device according to claim 4, characterized in that The included angle between the first substrate and the first direction is 45°, and the included angle between the second substrate and the first direction is 45°.

7. The frequency selection device according to any one of claims 2 to 6, characterized in that: The first gap area does not overlap with the second gap area.

8. The frequency selection device according to any one of claims 1 to 7, characterized in that: Each of the metal connecting plates is parallel to the first direction, each of the FSS units is plugged into a corresponding slot structure along a third direction, and the first direction is perpendicular to the third direction.

9. The frequency selection device according to claim 8, characterized in that A surface of each of the FSS units includes a metal pattern, wherein the metal pattern includes a first metal structure extending along the third direction and a second metal structure extending along a direction perpendicular to the third direction.

10. The frequency selection device according to claim 9, characterized in that The metal pattern further includes a third metal structure extending along the third direction, and the first metal structure is coupled to the third metal structure.

11. The frequency selection device according to any one of claims 1 to 10, characterized in that: Every two adjacent metal shells are physically connected to the metal connecting plate therebetween.

12. The frequency selection device according to any one of claims 1 to 10, characterized in that: Every two adjacent metal shells are coupled to a metal connecting plate therebetween.

13. The frequency selection device according to any one of claims 1 to 12, characterized in that: The frequency selection device further includes a signal transmission component, and at least one of the metal shells is used to accommodate the signal transmission component.

14. The frequency selection device according to claim 13, characterized in that: The signal transmission device includes a packaging shell, and at least one metal shell is used to accommodate the packaging shell.

15. The frequency selection device according to claim 13 or 14, characterized in that: The signal transmission device is used to connect an antenna element of at least one working frequency band.

16. The frequency selection device according to claim 15, characterized in that The multiple metal shells are distributed at equal intervals, and every two adjacent antenna elements with the same working frequency band are respectively connected to the signal transmission devices located in the two metal shells, and the distance between every two adjacent antenna elements with the same working frequency band is an integer multiple of the distance between every two adjacent metal shells.

17. A base station antenna, characterized in that: include: An antenna array and a frequency selection device as claimed in any one of claims 1 to 16, wherein the antenna array is used for transmitting and receiving signals, and the frequency selection device is used for filtering.

18. The base station antenna according to claim 17, wherein: The antenna array includes a first antenna array and a second antenna array. The frequency selection device is located between the first antenna array and the second antenna array. The frequency selection device is used to reflect signals of a first frequency band transmitted by the first antenna array and transmit signals of a second frequency band transmitted by the second antenna array.

19. A base station device, characterized in that: include: A radio frequency module and a base station antenna as described in claim 17 or 18, wherein the radio frequency module is used to convert a baseband signal into a high-frequency signal and send it to the base station antenna, and convert a high-frequency signal from the base station antenna into a baseband signal.

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