Frequency selective unit, frequency selective surface, and antenna base station

Abstract

A frequency selective unit, a frequency selective surface, and an antenna base station. The frequency selective unit comprises a metal reflector plate and at least two conductive material pattern layers, wherein through holes are provided in the metal reflector plate, the at least two conductive material pattern layers run through the through holes, and there is a gap between the conductive material pattern layers and the metal reflector plate; and at least one conductive material pattern layer comprises a first transmission mode, and at least the other conductive material pattern layer comprises a second transmission mode, and in a transition band, electromagnetic waves in the two transmission modes have opposite phases and cancel each other, such that the electromagnetic waves cannot be transmitted through the frequency selective unit; moreover, an electromagnetic wave transmission zero can be generated in the transition band, and a sharp roll-off is formed at an out-of-band edge of a second band, thereby realizing high-frequency selectivity. The conductive material pattern layers are not parallel to the metal reflector plate, the transmission direction of the electromagnetic waves is parallel to the surfaces of the conductive material pattern layers, and it is not necessary to provide a metallized via hole between the at least two conductive material pattern layers to perform electrical connection, thereby simplifying the manufacturing process and processing difficulty of the frequency selective unit.

Description

Frequency selection unit, frequency selection surface and antenna base station

[0001] This invention claims priority to Chinese Patent Application No. 202410565248.6, filed with the State Intellectual Property Office of China on May 8, 2024, entitled “Frequency Selection Unit, Frequency Selection Surface and Antenna Base Station”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, specifically to a frequency selection unit, a frequency selection surface, and an antenna base station. Background Technology

[0003] Frequency selective surfaces (FSS) are widely used in the microwave, infrared, and visible light bands due to their specific frequency selectivity. To improve the frequency selectivity performance of FSSs and achieve rapid transmittance roll-off, an effective method is to construct a transmission null at the outer edge of the passband. Existing FSSs of this type generally include at least one metal plate, with resonant structures on both sides of the metal plate. The metal plate and resonant structures are usually arranged in parallel and spaced apart. Vias are machined into the metal plate so that transmission lines can pass through the vias and electrically connect to the resonant structures on both sides of the metal plate. This structure of the FSS can construct a transmission null at the outer edge of the passband.

[0004] However, the through-hole processing technology on metal plates is relatively complex, especially when the metal plate has a multi-layer structure. The through-hole processing and the precision control between multiple through holes are difficult, which affects the performance of the frequency selection surface. Summary of the Invention

[0005] In view of this, this application provides a frequency selection unit, a frequency selection surface, and an antenna base station to solve the problem that when two existing resonant structures need to be electrically connected through metallized vias, the processing difficulty and precision control of the metallized vias are high, which can easily affect the performance of the frequency selection surface.

[0006] In a first aspect, embodiments of this application provide a frequency selection unit, comprising: a metal reflector and at least two sets of conductive material pattern layers. The metal reflector has through-holes. At least two sets of the conductive material pattern layers are disposed within the through-holes, and a gap exists between the conductive material pattern layers and the metal reflector. At least one set of the conductive material pattern layers includes a first transmission mode, and at least another set of the conductive material pattern layers includes a second transmission mode. In a transition band frequency band, the electromagnetic waves in the first transmission mode and the electromagnetic waves in the second transmission mode are out of phase.

[0007] The frequency selection unit provided in this application embodiment has a conductive material pattern layer that is not parallel to the metal reflector. The conductive material pattern layer needs to pass through a through-hole in the metal reflector. The transmission direction of the electromagnetic wave is parallel to the surface of the conductive material pattern layer. There is no need to set metallized vias for electrical connection between at least two sets of conductive material pattern layers, thereby simplifying the manufacturing process and reducing the processing difficulty of the frequency selection unit. In at least two different transmission modes corresponding to at least two sets of conductive material pattern layers, the electromagnetic waves in at least two transmission modes can have opposite phases in the transition band, achieving mutual cancellation of electromagnetic waves and preventing electromagnetic waves from being transmitted through the frequency selection unit. At the same time, an electromagnetic wave transmission zero point can be generated between the first and second frequency bands, forming a steep drop at the outer edge of the second frequency band, achieving high frequency selectivity. Meanwhile, the electromagnetic waves in at least two transmission modes have the same or similar phase in the second frequency band, and the electromagnetic waves corresponding to the second frequency band can be transmitted through the frequency selection unit, achieving in-band flatness in the second frequency band and widening the bandwidth of the second frequency band.

[0008] In one possible design, the thickness direction of the conductive material pattern layer is perpendicular to the thickness direction of the metal reflector. That is, the conductive material pattern layer can be inserted into the through-hole in an orientation perpendicular to the metal reflector. The first antenna and the second antenna are respectively positioned on opposite sides of the metal reflector along its thickness direction, allowing the transmission direction of the electromagnetic wave between the first and second antennas to be parallel to the surface of the conductive material pattern layer. When the electromagnetic wave passes through the conductive material pattern layer, it can excite the corresponding transmission mode on the conductive material pattern layer. Within the transition band, the polarization directions of the electromagnetic waves under both transmission modes are perpendicular to the surface of the conductive material pattern layer and are opposite. This allows the electromagnetic waves under the two transmission modes to cancel each other out when propagating in a direction parallel to the conductive material pattern layer, preventing the electromagnetic wave from penetrating the frequency selection unit and thus narrowing the transition band.

[0009] In one possible design, the frequency selection unit further includes a dielectric substrate, which is disposed within the through-hole, and the conductive material pattern layer is connected to the dielectric substrate. Exemplarily, the dielectric substrate may have a metal layer, which can be etched into a predetermined pattern shape. This conductive material pattern layer and the dielectric substrate are an integral structure, and can be integrally disposed within the through-hole of the metal reflector. Exemplarily, the conductive material pattern layer can also be independently fabricated from sheet metal and fixed to the dielectric substrate by bonding or other processes, thereby allowing the entire assembly consisting of the dielectric substrate and the conductive material pattern layer to be integrally disposed within the through-hole. The combination of the conductive material pattern layer and the dielectric substrate facilitates the assembly and fixation of the conductive material pattern layer, ensuring structural stability.

[0010] In one possible design, the dielectric substrate has a slot that extends through the edge of one end of the dielectric substrate. The through-hole includes at least a first hole and a second hole, separated by a first rib. The slot engages with the first rib, and portions of the dielectric substrate located on either side of the slot are inserted into the corresponding first and second holes. The first rib is a structure on the metal reflector located between the first and second holes. During assembly of the dielectric substrate and the metal reflector, the end of the slot extending through the edge of the dielectric substrate can be aligned with the first rib. As the portions of the dielectric substrate on either side of the slot are inserted into the corresponding first and second holes, the slot and the first rib slide relative to each other. When the dielectric substrate is inserted into the through-hole to a preset depth, it can be fixed to a corresponding structure within the antenna base station using a bracket or similar structure. At this point, the non-through end of the dielectric substrate in the slot can contact the first rib for positioning. Alternatively, in some embodiments, the non-through end of the dielectric substrate in the slot may not contact the first rib, and the dielectric substrate can be positioned and fixed using an external bracket or similar structure.

[0011] In one possible design, the dielectric substrate is provided with conductive material pattern layers on opposite side surfaces. The conductive material pattern layer on one side of the dielectric substrate includes the first transmission mode, and the conductive material pattern layer on the other side of the dielectric substrate includes the second transmission mode. The conductive material pattern layers on both sides of the dielectric substrate can excite different transmission modes. In the two transmission modes, electromagnetic waves in the transition band can achieve phase cancellation, preventing the electromagnetic waves from penetrating the frequency selection unit and generating a deep transmission null. A steep drop is formed at the out-of-band edge of the second frequency band (transparency band), achieving high frequency selectivity.

[0012] In one possible design, the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, which are arranged in parallel. A set of conductive material pattern layers is disposed on the first dielectric substrate, and another set of conductive material pattern layers is disposed on the second dielectric substrate. The conductive material pattern layers on the first dielectric substrate include a first transmission mode, and the conductive material pattern layers on the second dielectric substrate include a second transmission mode. Therefore, by forming two sets of conductive material pattern layers on two separate dielectric substrates, the distance between the two sets of conductive material pattern layers can be easily adjusted. Furthermore, when the distance between the two sets of conductive material pattern layers is large, the space between the two dielectric substrates can be air, meaning there is no need to fill the space between the two dielectric substrates with a solid dielectric, thus contributing to weight reduction.

[0013] In one possible design, the conductive material pattern layer on the first dielectric substrate includes a first portion and a second portion, which are respectively disposed on both sides of the first dielectric substrate. The first and second portions of the conductive material pattern layer can be coupled together, thereby allowing for more flexible placement of the conductive material pattern layer on the dielectric substrate. And / or, the conductive material pattern layer on the second dielectric substrate includes a third portion and a fourth portion, which are respectively disposed on both sides of the second dielectric substrate. The third and fourth portions of the conductive material pattern layer can also be coupled together. That is, the arrangement of the conductive material pattern layer on the second dielectric substrate can be similar to that on the first dielectric substrate. Different portions of the same set of conductive material pattern layers can be disposed on both sides of the corresponding dielectric substrate and can be coupled together, thereby improving the flexibility of the conductive material pattern layer placement and facilitating the configuration of the desired transmission mode. In other embodiments, a first metallized via can be provided on the first dielectric substrate, through which the first portion and the second portion can be electrically connected; similarly, a second metallized via can be provided on the second dielectric substrate, through which the third portion and the fourth portion can be electrically connected. This embodiment does not limit the method of using metallized vias to achieve electrical connection.

[0014] In one possible design, the dielectric substrate includes a third dielectric substrate and a fourth dielectric substrate, which form a predetermined angle with each other. Conductive material pattern layers are respectively disposed on opposite side surfaces of the third dielectric substrate. The conductive material pattern layer on one side surface of the third dielectric substrate includes the first transmission mode, and the conductive material pattern layer on the other side surface of the third dielectric substrate includes the second transmission mode. Similarly, conductive material pattern layers are respectively disposed on opposite side surfaces of the fourth dielectric substrate. The conductive material pattern layer on one side surface of the fourth dielectric substrate includes the second transmission mode, and the conductive material pattern layer on the other side surface of the fourth dielectric substrate includes the second transmission mode. Specifically, the electromagnetic waves transmitted by the conductive material pattern layer on the third dielectric substrate and the electromagnetic waves transmitted by the conductive material pattern layer on the fourth dielectric substrate can form a dual polarization. That is, the electromagnetic waves transmitted by the conductive material pattern layer on the third dielectric substrate in the first frequency band (reflection band), the second frequency band (transmission band), and the transition band have similar effects to the electromagnetic waves transmitted by the conductive material pattern layer on the fourth dielectric substrate in the first frequency band, the second frequency band, and the transition band. In the first frequency band, the electromagnetic waves can be reflected by the metal reflector. In the second frequency band, the frequency selection unit acts as a transmission unit for the electromagnetic waves. In the transition band, the electromagnetic waves in the two transmission modes are out of phase and cancel each other out, which can generate a transmission zero point of electromagnetic waves in the transition band. A steep drop is formed at the outer edge of the second frequency band, thus achieving high frequency selectivity.

[0015] In one possible design, the third medium plate is provided with a first slot, and the fourth medium plate is provided with a second slot. The third medium plate and the fourth medium plate are respectively cross-connected from both sides of the metal reflector through the cooperation of the first slot and the second slot, which can ensure the stability of the cooperation between the two medium plates and the metal reflector.

[0016] In one possible design, the metal reflector has a metal cavity with a accommodating space. This metal cavity can accommodate functional components, such as antenna feed lines and phase shifters, thereby improving the integration of the antenna base station and enabling miniaturized design.

[0017] In one possible design, the conductive material pattern layer comprises a metal sheet, or the conductive material pattern layer comprises a metal layer formed on the dielectric substrate. The conductive material pattern layer can be independently fabricated from sheet metal and has a stable structural morphology. For example, the conductive material pattern layer is a metal sheet with a predetermined pattern shape, which can independently pass through through-holes in the metal reflector, and a gap can be maintained between adjacent metal sheets. Alternatively, in other embodiments, the dielectric substrate may have a metal layer, which can be etched to form a predetermined pattern shape. This conductive material pattern layer is an integral structure with the dielectric substrate and can be integrally inserted into the through-holes of the metal reflector.

[0018] Secondly, this application also provides a frequency selection surface, which includes the frequency selection unit provided in the first aspect of this application. The frequency selection surface including the aforementioned frequency selection unit has similar technical effects to the aforementioned frequency selection unit, and will not be described in detail here.

[0019] In one possible design, multiple frequency selection units are provided, and the multiple frequency selection units are arranged periodically, thereby meeting the usage requirements of antennas with different radiation ranges.

[0020] In one possible design, multiple frequency selection units share a single metal reflector, thereby ensuring the structural stability of the frequency selection surface.

[0021] Thirdly, this application also provides an antenna base station, comprising a first antenna, a second antenna, and a frequency selection surface provided in the second aspect of this application, wherein the frequency selection surface is disposed between the first antenna and the second antenna. The transmission direction of the electromagnetic wave between the first antenna and the second antenna is parallel to the surface of the conductive material pattern layer. When the electromagnetic wave passes through the conductive material pattern layer, it can excite the corresponding transmission mode on the conductive material pattern layer. Within the transition band, the polarization directions of the electromagnetic waves under both transmission modes are perpendicular to the surface of the conductive material pattern layer and are opposite. This allows the electromagnetic waves under the two transmission modes to cancel each other out when propagating in a direction parallel to the conductive material pattern layer, thus preventing the electromagnetic wave from penetrating the frequency selection unit and facilitating the narrowing of the transition band.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 is a schematic diagram of the structure of the frequency selective surface provided in an embodiment of this application;

[0025] Figure 2 is a schematic diagram of the application of the frequency selection surface in an antenna base station according to an embodiment of this application;

[0026] Figure 3 is a schematic diagram of the structure of a frequency selection unit provided in an embodiment of this application;

[0027] Figure 4 is a schematic diagram of a conductive material patterned layer provided in an embodiment of this application;

[0028] Figure 5 is a schematic diagram of a conductive material patterned layer provided in another embodiment of this application;

[0029] Figure 6 is a schematic diagram of the structure of a metal reflector provided in one embodiment of this application;

[0030] Figure 7 is a schematic diagram of the structure of a frequency selection unit provided in another embodiment of this application;

[0031] Figure 8 is a front view of the first medium plate provided in an embodiment of this application;

[0032] Figure 9 is a rear view of the first medium plate provided in an embodiment of this application;

[0033] Figure 10 is a schematic diagram of the structure of a frequency selection unit provided in another embodiment of this application;

[0034] Figure 11 is a schematic diagram of the structure of a metal reflector provided in another embodiment of this application;

[0035] Figure 12 is a schematic diagram of the structure of a metal reflector provided in another embodiment of this application;

[0036] Figure 13 is a schematic diagram of the structure of a frequency selection unit provided in another embodiment of this application.

[0037] Reference numerals: 1-Metal reflector; 11-Through hole; 11a-First hole; 11b-Second hole; 11c-Third hole; 11d-Fourth hole; 11e-Fifth hole; 11f-Sixth hole; 11g-Hole; 12-First rib; 13-Second rib; 14-Metal cavity; 2-Conductive material pattern layer; 21-First part; 22-Second part; 3-Dielectric substrate; 3a-First dielectric substrate; 3b-Second dielectric substrate; 3c-Third dielectric substrate; 3d-Fourth dielectric substrate; 31-Slot; 100-Frequency selection unit; 200-First antenna; 300-Second antenna; 400-Frequency selection surface; Z1-Thickness direction; Z2-Thickness direction. Detailed Implementation

[0038] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0039] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0040] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0042] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0043] A frequency selective surface (FSS) is a two-dimensional periodic array structure that is essentially a spatial filter. It interacts with electromagnetic waves and exhibits distinct bandpass or bandstop filtering characteristics. Due to its specific frequency selectivity, FSS is widely used in the microwave, infrared, and visible light bands.

[0044] To improve the frequency selectivity of frequency selective surfaces and achieve rapid transmittance roll-off, an effective method is to construct a transmission null at the outer edge of the passband. Existing frequency selective surfaces of this type generally include at least one metal plate, with resonant structures on both sides of the metal plate. The metal plate and resonant structures are typically arranged in parallel and spaced apart. Vias are machined into the metal plate to allow transmission lines to pass through and electrically connect to the resonant structures on both sides of the metal plate. This structure allows for the construction of a transmission null at the outer edge of the passband. However, the manufacturing process of the vias on the metal plate and the electrical connections between the vias and the resonant structures is complex, especially when the metal plate is multi-layered. Each layer of the metal plate requires vias, and high precision is required between multiple vias. The machining and precision control of numerous vias, as well as the machining and precision control of the electrical connections between the vias and the resonant structures, are challenging. Low machining and fitting precision will affect the performance of the frequency selective surface. In addition, existing resonant structures are usually planar in shape and parallel to the metal plate. The electromagnetic waves transmitted and received by the antenna need to be transmitted in a direction perpendicular to the plane of the resonant structure, which can easily result in a small transmission bandwidth and thus poor antenna performance.

[0045] This application provides a frequency selection unit that can be applied to a frequency selection surface. Figure 1 is a schematic diagram of the structure of the frequency selection surface provided in this application. Referring to Figure 1, the frequency selection surface 400 can, by way of example, include at least one frequency selection unit 100. When the frequency selection surface 400 includes multiple frequency selection units 100, the multiple frequency selection units 100 can be arranged periodically. For example, the multiple frequency selection units 100 can form a rectangular array, a square array, a circular array, etc. In addition, the frequency selection surface 400 can be applied to an antenna base station. Figure 2 is a schematic diagram of the frequency selection surface 400 provided in this application applied to an antenna base station. Referring to Figure 2, the antenna base station can include at least a first antenna 200 and a second antenna 300. The first antenna 200 and the second antenna 300 are respectively located on both sides of the frequency selection surface 400 in the thickness direction of the metal reflector 1. The first antenna 200 can operate in a first frequency band, and the second antenna 300 can operate in a second frequency band. The highest frequency of the first frequency band can be lower than the lowest frequency of the second frequency band. The first frequency band can be a reflection band, that is, the frequency band in which the frequency selective surface 400 reflects electromagnetic waves. The second frequency band can be a transmission band, that is, the frequency band in which the frequency selective surface 400 transmits electromagnetic waves. In other words, the frequency selective surface 400 provided in this application can reflect electromagnetic waves in the first frequency band and transmit electromagnetic waves in the second frequency band, thereby ensuring that the first antenna 200 and the second antenna 300 perform optimally in their respective operating frequency bands.

[0046] Figure 3 is a schematic diagram of the structure of the frequency selection unit 100 provided in an embodiment of this application. Referring to Figure 3, the frequency selection unit 100 provided in this embodiment may include a metal reflector 1 and at least two sets of conductive material pattern layers 2. The metal reflector 1 can be a sheet metal part with a certain thickness, such as a copper plate or aluminum alloy plate, which can reflect electromagnetic waves. In some embodiments, the metal reflector 1 can be a flat plate, and both sides of the flat plate in the thickness direction can be planar. In some embodiments, the surface of the metal reflector 1 can also be non-planar; for example, the surface of the metal reflector 1 may have protrusions, depressions, or other structures, giving the surface of the metal reflector 1 an uneven morphology. When the frequency selection surface 400 includes multiple frequency selection units 100, the multiple frequency selection units 100 can share a single metal reflector 1, thereby ensuring the structural stability of the frequency selection surface 400.

[0047] The conductive material pattern layer 2 can be a structure with a predetermined pattern shape formed from a conductive material. This conductive material can be a metal, such as copper, aluminum, or titanium, or a non-metallic polymer conductive material, such as PEDOT:PSS. The conductive material pattern layer 2 can be specifically designed according to the needs of different transmission or reflection segments, exhibiting strong variability and wide applicability. For example, Figure 4 is a front view of the conductive material pattern layer 2 provided in an embodiment of this application, and Figure 5 is a rear view of the conductive material pattern layer 2 provided in an embodiment of this application. Referring to Figures 4 and 5, the conductive material pattern layer 2 can include combinations of various shapes such as "I," "C," "L," and "U," and the specific combination method can be determined according to the required electromagnetic wave transmission mode. In one embodiment, the conductive material pattern layer 2 can be a separately manufactured sheet metal structure, for example, a predetermined pattern shape can be processed on a copper plate. This copper plate can be independently assembled in the frequency selection unit 100, thereby facilitating the assembly and independent adjustment of the conductive material pattern layer 2. In one embodiment, the conductive material pattern layer 2 can also be attached to the dielectric substrate 3, that is, a metal layer can be provided on the dielectric substrate 3, and the metal layer can be formed into a set pattern shape by etching process.

[0048] Figure 6 is a schematic diagram of the structure of a metal reflector 1 provided in one embodiment of this application. Referring to Figure 6, a through hole 11 may be provided on the metal reflector 1, which can penetrate through the thickness direction of the metal reflector 1. At least two sets of conductive material pattern layers 2 can be disposed in the through hole 11, and there is a gap between the conductive material pattern layer 2 and the metal reflector 1, that is, the conductive material pattern layer 2 does not contact the edge of the through hole 11 to avoid short circuit. At least one set of conductive material pattern layers 2 may include a first transmission mode, and at least another set of conductive material pattern layers 2 may include a second transmission mode. The first transmission mode and the second transmission mode are two different transmission modes.

[0049] In the second frequency band (i.e., the wave-transmitting band), electromagnetic waves can excite the transmission modes on the conductive material pattern layer 2. For example, when there are two sets of conductive material pattern layers 2, electromagnetic waves corresponding to the second frequency band can excite a first transmission mode on one set of conductive material pattern layers 2 and a second transmission mode on the other set. The electromagnetic waves in the first transmission mode and the electromagnetic waves in the second transmission mode have the same or similar phase, thus allowing the phases of the electromagnetic waves passing through the two sets of conductive material pattern layers 2 to superimpose. This enables the frequency selection unit 100 to transmit electromagnetic waves, improving the performance of the second antenna 300 operating in the second frequency band. In the transition band, the first and second transmission modes have opposite phases and similar amplitudes.

[0050] Between the first and second frequency bands, there is a transition band. Within this transition band, the frequency selective surface 400 reflects some electromagnetic waves while simultaneously transmitting others. In this transition band, the electromagnetic waves in the first and second transmission modes are out of phase, and their amplitudes can be the same or similar. The polarization directions of these two transmission modes are opposite, allowing them to cancel each other out. This prevents the electromagnetic waves from being transmitted through the frequency selective unit 100. Simultaneously, a transmission zero point can be generated between the first and second frequency bands, creating a steep drop at the outer edge of the second frequency band (transparent band), achieving high frequency selectivity and intra-band flatness, thus widening the bandwidth of the second frequency band.

[0051] Therefore, in the frequency selection unit 100 provided in this embodiment, the conductive material pattern layer 2 is not parallel to the metal reflector 1. The conductive material pattern layer 2 needs to pass through the through hole 11 on the metal reflector 1. The transmission direction of the electromagnetic wave is parallel to the surface of the conductive material pattern layer 2. There is no need to set metallized vias for electrical connection between at least two sets of conductive material pattern layers 2, thereby simplifying the manufacturing process and processing difficulty of the frequency selection unit 100. In at least two different transmission modes corresponding to at least two sets of conductive material pattern layers 2, the electromagnetic waves in at least two transmission modes can have opposite phases in the transition band frequency band, realizing mutual cancellation of electromagnetic waves, so that electromagnetic waves cannot be transmitted through the frequency selection unit 100. At the same time, an electromagnetic wave transmission zero point can be generated between the first frequency band and the second frequency band, forming a steep drop at the outer edge of the second frequency band, realizing high frequency selectivity. Meanwhile, the electromagnetic waves in at least two transmission modes have the same or similar phase in the second frequency band, and the electromagnetic waves corresponding to the second frequency band can be transmitted through the frequency selection unit 100, which can realize the in-band flatness of the second frequency band and broaden the bandwidth of the second frequency band.

[0052] In one embodiment, referring to FIG2, the thickness direction Z2 of the conductive material pattern layer 2 is perpendicular to the thickness direction Z1 of the metal reflector 1. That is, the conductive material pattern layer 2 can be inserted into the through hole 11 in an orientation perpendicular to the metal reflector 1. Referring to FIG2, the first antenna 200 and the second antenna 300 are respectively disposed on both sides of the metal reflector 1 in its thickness direction Z1, so that the transmission direction of the electromagnetic wave between the first antenna 200 and the second antenna 300 can be parallel to the surface of the conductive material pattern layer 2. When the electromagnetic wave passes through the conductive material pattern layer 2, it can excite the corresponding transmission mode on the conductive material pattern layer 2. In the transition band frequency band, the polarization direction of the electromagnetic wave in both transmission modes can be perpendicular to the surface of the conductive material pattern layer 2 and the polarization directions are opposite. Thus, when the electromagnetic wave is transmitted in a direction parallel to the conductive material pattern layer 2, the electromagnetic waves in the two transmission modes can cancel each other out, thereby preventing the electromagnetic wave from penetrating the frequency selection unit 100, which is beneficial for narrowing the transition band frequency band.

[0053] In one embodiment, as described above, the conductive material pattern layer 2 can be independently formed from sheet metal. The conductive material pattern layer 2 has a stable structural shape; for example, the conductive material pattern layer 2 is a metal sheet with a predetermined pattern shape. The metal sheet can independently pass through the through-holes 11 on the metal reflector 1, and a gap can be maintained between adjacent metal sheets. The conductive material pattern layer 2 can be connected to the corresponding structure in the antenna base station through a bracket or other structure; this embodiment does not impose any limitations on this.

[0054] In one embodiment, referring to FIG3, the frequency selection unit 100 may further include a dielectric substrate 3, and a conductive material pattern layer 2 may be connected to the dielectric substrate 3. The dielectric substrate 3 may be a flame-retardant material (FR-4) dielectric substrate 3, a Rogers dielectric substrate 3, a hybrid dielectric substrate 3 of Rogers and FR-4, etc. Here, FR-4 is a designation for a flame-retardant material grade, and the Rogers dielectric substrate 3 is a high-frequency board. Exemplarily, as described above, the dielectric substrate 3 may have a metal layer, which may be etched into a predetermined pattern shape. This conductive material pattern layer 2 is an integral structure with the dielectric substrate 3 and can be integrally inserted into the through-hole 11 of the metal reflector 1. Exemplarily, the conductive material pattern layer 2 may also be independently machined from sheet metal and fixed to the dielectric substrate 3 by bonding or other processes, thereby allowing the entire assembly consisting of the dielectric substrate 3 and the conductive material pattern layer 2 to be integrally inserted into the through-hole 11. The combination of the conductive material pattern layer 2 and the dielectric substrate 3 facilitates the assembly and fixation of the conductive material pattern layer 2, ensuring the stability of the structure. The dielectric substrate 3 can be connected to the corresponding structure in the antenna base station via a bracket or other structure; this embodiment does not impose any limitations on this.

[0055] In one embodiment, referring to FIG3, a dielectric substrate 3 may be provided, and conductive material pattern layers 2 may be respectively provided on opposite side surfaces of the dielectric substrate 3. The conductive material pattern layer 2 on one side of the dielectric substrate 3 includes a first transmission mode, and the conductive material pattern layer 2 on the other side of the dielectric substrate 3 includes a second transmission mode. The conductive material pattern layers 2 on the two side surfaces of the dielectric substrate 3 may be different. For example, the conductive material pattern layer 2 on one side of the dielectric substrate 3 may include a combination of "I" and "C" shapes, and the conductive material pattern layer 2 on the other side of the dielectric substrate 3 may include a combination of "I" and "U" shapes. Thus, the conductive material pattern layers 2 on both sides of the dielectric substrate 3 can excite different transmission modes. In the two transmission modes, electromagnetic waves in the transition band frequency band can achieve phase cancellation, and the electromagnetic waves cannot penetrate the frequency selection unit 100, generating a deeper transmission zero point and forming a steep drop at the outer edge of the second frequency band (transparency band), achieving high frequency selectivity.

[0056] In one embodiment, referring to FIG3, a slot 31 may be provided on the dielectric substrate 3. The slot 31 may be linear and may penetrate the edge of one end of the dielectric substrate 3, but not the edge of the opposite end of the dielectric substrate 3. Referring to FIG6, the through hole 11 includes at least a first hole 11a and a second hole b, which are separated by a first partition 12. Both the first hole 11a and the second hole b may be elongated, so that the portions of the dielectric substrate 3 located on both sides of the slot 31 can be inserted into the corresponding first hole 11a and second hole b, respectively. The first partition 12 is a structure on the metal reflector 1 located between the first hole 11a and the second hole b. When assembling the dielectric plate 3 and the metal reflector 1, one end of the slot 31 that passes through the edge of the dielectric plate 3 can be aligned with the first partition 12. As the portions of the dielectric plate 3 located on both sides of the slot 31 are inserted into the corresponding first hole 11a and second hole b, the slot 31 and the first partition 12 slide relative to each other. When the dielectric plate 3 is inserted into the through hole 11 to reach a preset depth, the dielectric plate 3 can be fixed to the corresponding structure in the antenna base station by a bracket or other structure. At this time, one end of the non-through dielectric plate 3 on the slot 31 can contact the first partition 12 to achieve limiting; or, in some embodiments, one end of the non-through dielectric plate 3 on the slot 31 can also not contact the first partition 12, and the dielectric plate 3 can be limited and fixed by an external bracket or other structure. Furthermore, the size and positional relationship of the first hole 11a and the second hole b can determine the structural form of the first rib 12. The first hole 11a and the second hole b can be designed according to the required wave transmission effect in the first frequency band (reflection section).

[0057] In one embodiment, FIG7 is a schematic diagram of the structure of a frequency selection unit 100 provided in another embodiment of this application. Referring to FIG7, the dielectric substrate 3 may include a first dielectric substrate 3a and a second dielectric substrate 3b. The first dielectric substrate 3a and the second dielectric substrate 3b may be arranged in parallel. A set of conductive material pattern layers 2 may be disposed on the first dielectric substrate 3a, and another set of conductive material pattern layers 2 may be disposed on the second dielectric substrate 3b. The conductive material pattern layers 2 on the first dielectric substrate 3a include a first transmission mode, and the conductive material pattern layers 2 on the second dielectric substrate 3b include a second transmission mode. The conductive material pattern layers 2 may be disposed on one side surface of the first dielectric substrate 3a, while the other side surface may not be disposed on the same surface. The conductive material pattern layers 2 may be disposed on one side surface of the second dielectric substrate 3b, while the other side surface may not be disposed on the same surface. The first dielectric substrate 3a and the second dielectric substrate 3b may be spaced apart to ensure that there is a preset distance between the two sets of conductive material pattern layers 2. Therefore, by forming two sets of conductive material pattern layers 2 on two dielectric plates 3 respectively, the distance between the two sets of conductive material pattern layers 2 can be easily adjusted. In addition, when the distance between the two sets of conductive material pattern layers 2 is large, the space between the two dielectric plates 3 can be air, that is, there is no need to fill the space between the two dielectric plates 3 with solid medium, which is beneficial to achieving lightweighting.

[0058] In one embodiment, FIG8 is a front view of the first dielectric substrate 3a provided in the embodiment of the present application, and FIG9 is a rear view of the first dielectric substrate 3a provided in the embodiment of the present application. Referring to FIG8 and FIG9, the conductive material pattern layer 2 on the first dielectric substrate 3a may include a first part 21 and a second part 22. The first part 21 and the second part 22 are respectively disposed on the two side surfaces of the first dielectric substrate 3a. The first part 21 and the second part 22 can be coupled and connected, that is, the first part 21 and the second part 22 can be directly connected without using a conductive structure, thereby facilitating the manufacturing of the conductive material pattern layer 2 and the first dielectric substrate 3a.

[0059] In some other embodiments, a first metallized via may be provided on the first dielectric substrate 3a, and the first portion 21 and the second portion 22 may be electrically connected through the first metallized via.

[0060] Therefore, a set of conductive material pattern layers 2 capable of realizing a transmission mode does not need to be entirely disposed on one side surface of the dielectric substrate 3. Alternatively, a portion of the conductive material pattern layers 2 can be disposed on one side surface of the dielectric substrate 3, while the other portion is disposed on the other side surface. The two portions of the conductive material pattern layers 2 can be electrically connected via metallized vias or transmission lines, or connected via capacitive coupling. This allows for more flexible placement of the conductive material pattern layers 2 on the dielectric substrate 3.

[0061] In one embodiment, the conductive material pattern layer 2 on the second dielectric substrate 3b may include a third portion and a fourth portion, which are respectively disposed on both sides of the second dielectric substrate 3b. The third and fourth portions can be coupled together, meaning they can be directly connected without a conductive structure, thus facilitating the manufacturing of the conductive material pattern layer 2 and the second dielectric substrate 3b. In other embodiments, a second metallized via may be provided on the second dielectric substrate 3b, through which the third and fourth portions are electrically connected. In other words, the arrangement of the conductive material pattern layer 2 on the second dielectric substrate 3b can be similar to that on the first dielectric substrate 3a. Different portions of the same set of conductive material pattern layers 2 can be disposed on both sides of the corresponding dielectric substrate 3 and electrically connected through metallized vias or transmission lines, or connected through capacitive coupling, thereby improving the flexibility of the conductive material pattern layer 2 configuration and facilitating the configuration of the desired transmission mode.

[0062] In one embodiment, FIG10 is a schematic diagram of the structure of a frequency selection unit 100 provided in another embodiment of this application. Referring to FIG10, the dielectric substrate 3 includes a third dielectric substrate 3c and a fourth dielectric substrate 3d, and the third dielectric substrate 3c and the fourth dielectric substrate 3d form a preset angle. For example, the angle can be a 90° angle, that is, the third dielectric substrate 3c and the fourth dielectric substrate 3d are perpendicular to each other. Of course, in some other embodiments, the angle can also be other angles, such as 85°, 95°, 100°, etc., all of which can achieve dual polarization.

[0063] Conductive material pattern layers 2 are respectively disposed on opposite two surfaces of the third dielectric substrate 3c, and the conductive material pattern layer 2 on one surface of the third dielectric substrate 3c includes a first transmission mode, while the conductive material pattern layer 2 on the other surface of the third dielectric substrate 3c includes a second transmission mode. Similarly, conductive material pattern layers 2 are respectively disposed on opposite two surfaces of the fourth dielectric substrate 3d, and the conductive material pattern layer 2 on one surface of the fourth dielectric substrate 3d includes a second transmission mode, while the conductive material pattern layer 2 on the other surface of the fourth dielectric substrate 3d includes a second transmission mode. The electromagnetic waves transmitted by the conductive material pattern layer 2 on the third dielectric plate 3c and the electromagnetic waves transmitted by the conductive material pattern layer 2 on the third dielectric plate 3 can form a dual polarization. That is, the electromagnetic waves transmitted by the conductive material pattern layer 2 on the third dielectric plate 3c in the first frequency band (reflection band), the second frequency band (transmission band), and the transition band have similar effects to the electromagnetic waves transmitted by the conductive material pattern layer 2 on the fourth dielectric plate 3d in the first frequency band, the second frequency band, and the transition band. In the first frequency band, they can be reflected by the metal reflector 1. In the second frequency band, the frequency selection unit 100 transmits the electromagnetic waves. In the transition band, the electromagnetic waves in the two transmission modes are out of phase and cancel each other out, which can generate a zero point of electromagnetic wave transmission in the transition band. A steep drop is formed at the outer edge of the second frequency band, realizing high frequency selectivity.

[0064] In one embodiment, a first slot may be provided on the third dielectric plate 3c, and a second slot may be provided on the fourth dielectric plate 3d. The structure of the first slot and the second slot is similar to that of the aforementioned slot 31, that is, the first slot can penetrate the third dielectric plate 3c at one end in its length direction, while the other end does not penetrate the third dielectric plate 3c. The second slot can penetrate the fourth dielectric plate 3d at one end in its length direction, while the other end does not penetrate the fourth dielectric plate 3d. Figure 11 is a schematic diagram of the structure of the metal reflector 1 provided in another embodiment of this application. Referring to Figure 11, the through hole 11 includes at least a third hole c and a fourth hole d. The third hole c and the fourth hole d can be separated by a second partition 13. The first slot engages with the second partition 13 from one side of the metal reflector 1 in the thickness direction. The portions of the third dielectric plate 3c located on both sides of the first slot are respectively inserted into the corresponding third hole c and fourth hole d. The through-hole 11 also includes at least a fifth hole 11e and a sixth hole 11f, which are separated by a second partition 13. The arrangement direction of the fifth hole 11e and the sixth hole 11f forms a preset angle with the arrangement direction of the third hole c and the fourth hole d. The second slot engages with the second partition 13 from the other side of the metal reflector 1 in the thickness direction. The portions of the fourth dielectric plate 3d located on both sides of the second slot are respectively inserted into the corresponding fifth hole 11e and sixth hole 11f. The third dielectric plate 3c and the fourth dielectric plate 3d can be inserted into the corresponding holes from opposite sides of the metal reflector 1, and while the two dielectric plates 3 are inserted into the holes, they can also be mutually inserted and engaged through the first slot and the second slot to achieve a cross-set arrangement, which can ensure the stability of the engagement between the two dielectric plates 3 and the metal reflector 1. The third dielectric plate 3c and the fourth dielectric plate 3d can be fixed to the corresponding structure in the antenna base station by external brackets or other structures, which is not limited in this embodiment. In addition, the second partition 13 can be in the shape of a cross, which can separate the third hole c and the fourth hole d, as well as the fifth hole 11e and the sixth hole 11f. At the same time, by cooperating with the first slot and the second slot respectively, it can limit the two media plates 3.

[0065] In some embodiments, FIG12 is a schematic diagram of the structure of a metal reflector 1 provided in another embodiment of the present application. Referring to FIG12, the third hole c and the fourth hole d can be separated by a second partition 13, and a hole 11g can be provided on the second partition 13. The hole 11g on the second partition 13 communicates with the fifth hole 11e and the sixth hole 11f, respectively. That is, the fifth hole 11e, the sixth hole 11f, and the hole on the second partition 13 can form an elongated hole. The length of the elongated hole is greater than or equal to the width of one of the third dielectric plate 3c or the fourth dielectric plate 3d, so that the third dielectric plate 3c or the fourth dielectric plate 3d can be inserted into the elongated hole without the limitation of the second partition 13. The design of this hole can affect the reflection performance of the metal reflector 1 on electromagnetic waves in the first frequency band. That is, the design of the hole can be determined according to the transmission effect of electromagnetic waves in the corresponding frequency band.

[0066] In one embodiment, FIG13 is a schematic diagram of the structure of a frequency selection unit 100 provided in another embodiment of the present application. Referring to FIG13, a metal cavity 14 may be provided on the metal reflector 1, and the metal cavity 14 has a receiving space. The metal cavity 14 can accommodate functional components, such as antenna feed lines, phase shifters, etc., which is beneficial to improving the integration of the antenna base station and realizing miniaturized design.

[0067] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A frequency selection unit, characterized in that, include: A metal reflector, wherein the metal reflector is provided with through holes; At least two sets of conductive material pattern layers are disposed in the through hole, and there is a gap between the conductive material pattern layers and the metal reflector; at least one set of conductive material pattern layers includes a first transmission mode, and at least another set of conductive material pattern layers includes a second transmission mode, wherein in the transition band frequency band, the electromagnetic waves in the first transmission mode and the electromagnetic waves in the second transmission mode are out of phase.

2. The frequency selection unit according to claim 1, characterized in that, The thickness direction of the conductive material pattern layer is perpendicular to the thickness direction of the metal reflector.

3. The frequency selection unit according to claim 1 or 2, characterized in that, It also includes a dielectric substrate, which is disposed in the through hole, and the conductive material pattern layer is connected to the dielectric substrate.

4. The frequency selection unit according to claim 3, characterized in that, The medium plate is provided with a slot, which extends through the edge of one end of the medium plate; The through hole includes at least a first hole and a second hole, which are separated by a first partition. The slot engages with the first partition, and the portions of the medium plate located on both sides of the slot are respectively inserted into the corresponding first hole and second hole.

5. The frequency selection unit according to claim 3 or 4, characterized in that, The dielectric substrate is provided in one manner, and conductive material pattern layers are respectively provided on opposite two side surfaces of the dielectric substrate. The conductive material pattern layer on one side of the dielectric substrate includes the first transmission mode, and the conductive material pattern layer on the other side of the dielectric substrate includes the second transmission mode.

6. The frequency selection unit according to claim 3 or 4, characterized in that, The dielectric substrate includes a first dielectric substrate and a second dielectric substrate, which are arranged in parallel. A set of conductive material pattern layers is disposed on the first dielectric substrate, and another set of conductive material pattern layers is disposed on the second dielectric substrate. The conductive material pattern layers on the first dielectric substrate include a first transmission mode, and the conductive material pattern layers on the second dielectric substrate include a second transmission mode.

7. The frequency selection unit according to claim 6, characterized in that, The conductive material pattern layer on the first dielectric substrate includes a first part and a second part, which are respectively disposed on two side surfaces of the first dielectric substrate and coupled together; or, a first metallized via is provided on the first dielectric substrate, and the first part and the second part are electrically connected through the first metallized via. And / or, the conductive material pattern layer on the second dielectric substrate includes a third portion and a fourth portion, the third portion and the fourth portion being respectively disposed on two side surfaces of the second dielectric substrate, and the third portion and the fourth portion being coupled together; or, a second metallized via is provided on the second dielectric substrate, and the third portion and the fourth portion are electrically connected through the second metallized via.

8. The frequency selection unit according to claim 3 or 4, characterized in that, The dielectric substrate includes a third dielectric substrate and a fourth dielectric substrate, and the third dielectric substrate and the fourth dielectric substrate form a preset angle between them; The conductive material pattern layer is respectively disposed on the opposite two sides of the third dielectric substrate. The conductive material pattern layer on one side of the third dielectric substrate includes the first transmission mode, and the conductive material pattern layer on the other side of the third dielectric substrate includes the second transmission mode. The conductive material pattern layer is respectively disposed on two opposite sides of the fourth dielectric substrate. The conductive material pattern layer on one side of the fourth dielectric substrate includes the second transmission mode, and the conductive material pattern layer on the other side of the fourth dielectric substrate includes the second transmission mode.

9. The frequency selection unit according to claim 8, characterized in that, The third medium plate is provided with a first slot, and the fourth medium plate is provided with a second slot. The third medium plate and the fourth medium plate are respectively cross-connected from both sides of the metal reflector through the cooperation of the first slot and the second slot.

10. The frequency selection unit according to any one of claims 1-9, characterized in that, The metal reflector is provided with a metal cavity, and the metal cavity has a receiving space.

11. The frequency selection unit according to any one of claims 1-10, characterized in that, The conductive material pattern layer includes a metal sheet, or the conductive material pattern layer includes a metal layer formed on the dielectric substrate.

12. A frequency-selective surface, characterized in that, It includes at least one frequency selection unit as described in any one of claims 1-11.

13. The frequency selective surface according to claim 12, characterized in that, The frequency selection unit is provided in multiple ways, and the multiple frequency selection units are arranged periodically.

14. The frequency selective surface according to claim 13, characterized in that, Multiple frequency selection units share one metal reflector.

15. An antenna base station, characterized in that, It includes a first antenna, a second antenna, and a frequency selective surface as described in any one of claims 12-14, the frequency selective surface being disposed between the first antenna and the second antenna.

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