Base station antenna

Abstract

This invention provides a base station antenna, comprising a reflector, a low-frequency radiating element array, and a combined boundary. The low-frequency radiating element array is disposed on the reflector and includes two columns of low-frequency radiating elements symmetrically arranged along the longitudinal central axis of the reflector. The combined boundary includes a metal boundary and a PCB boundary, which are disposed on the reflector and located on the longitudinal central axis, sharing a common central axis. In this invention, a combined boundary formed by the metal boundary and the PCB boundary is disposed on the central axis of the two columns of low-frequency radiating elements, which effectively achieves horizontal bandwidth convergence.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a base station antenna. Background Technology

[0002] In the design of base station antennas (such as low-frequency antennas), due to their long operating wavelengths, the physical spacing of the radiating elements is strictly limited by the overall size of the antenna and the available space. This makes base station antennas prone to having excessively wide horizontal beamwidths or horizontal beamwidth divergence. It should be noted that in practical applications, an excessively wide horizontal beamwidth will cause the antenna's main lobe coverage angle in the horizontal direction to be too wide, exceeding the reasonable range required for a standard sector. This will cause signal energy leakage to adjacent sectors, leading to cross-sector interference. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a base station antenna that can help achieve horizontal beamwidth convergence.

[0004] In a first aspect, the present invention provides a base station antenna. The base station antenna includes a reflector, a low-frequency radiating element array, and a combined boundary; The low-frequency radiation unit array is disposed on the reflector plate, and the low-frequency radiation unit array includes two columns of low-frequency radiation units, which are symmetrically arranged along the longitudinal central axis of the reflector plate. The combined boundary includes a metal boundary and a PCB boundary, which are disposed on the reflector and located on the longitudinal central axis. The metal boundary and the PCB boundary are arranged along the same central axis.

[0005] In one implementation of the first aspect, each column of low-frequency radiating elements includes at least one unoffset radiating element and at least one offset radiating element. The at least one unoffset radiating element is arranged along a first array axis, which is parallel to the longitudinal central axis and has a first gap between them. The at least one offset radiating element is arranged along a second array axis, which is parallel to the longitudinal central axis and has a second gap between them. The second gap is greater than the first gap.

[0006] In one implementation of the first aspect, a high-frequency radiation unit array is further included. The high-frequency radiation unit array includes multiple high-frequency radiation units. Each high-frequency radiation unit is fixedly provided with a double-layer loading plate above it. The double-layer loading plate includes a first layer loading plate and a second layer loading plate arranged sequentially from bottom to top. There is a gap between the first layer loading plate and the second layer loading plate, and between the first layer loading plate and the high-frequency radiation unit.

[0007] In one implementation of the first aspect, the first loading sheet and the second loading sheet are either metal loading sheets or PCB loading sheets.

[0008] In one implementation of the first aspect, the spacing between the first layer loading sheet and the high-frequency radiation unit is 0.05-0.07 times the wavelength of the high-frequency center frequency; the spacing between the first layer loading sheet and the second layer loading sheet is 0.03-0.06 times the wavelength of the high-frequency center frequency.

[0009] In one implementation of the first aspect, the first and second loading sheets are square in shape and the side length of the first and second loading sheets is 0.09-0.18 times the wavelength of the high-frequency center frequency point; or, the first and second loading sheets are circular in shape and the diameter of the first and second loading sheets is 0.09-0.18 times the wavelength of the high-frequency center frequency point.

[0010] In one implementation of the first aspect, the high-frequency radiation unit array includes two sets of high-frequency radiation units, which are symmetrically arranged along the longitudinal central axis, and each set of high-frequency radiation units includes at least one column of high-frequency radiation units arranged in the longitudinal direction.

[0011] In one implementation of the first aspect, a third gap is provided between the bottom of the PCB boundary and the upper surface of the reflector, the third gap being 0.15-0.2 times the wavelength of the low-frequency center point.

[0012] In one implementation of the first aspect, an insulating film is further included, the insulating film being disposed between the metal boundary and the reflector.

[0013] In one implementation of the first aspect, the length of the metal boundary is 1-1.5 times the wavelength of the low-frequency center point, and the height of the metal boundary is 0.2-0.25 times the wavelength of the low-frequency center point.

[0014] The beneficial effects of this invention are as follows: First, by setting two columns of low-frequency radiating units on the reflector and symmetrically arranging them along the longitudinal central axis of the reflector, a corresponding low-frequency radiating unit array is formed. Based on the above low-frequency radiating unit array, a combined boundary formed by the metal boundary and the PCB boundary is then set on the central axis of the two columns of low-frequency radiating units (i.e., the longitudinal central axis of the reflector). Based on this combined boundary, the radiated energy that originally diffused to both sides of the horizontal direction can be gathered into the main radiation direction by cutting off surface waves, adjusting the field boundary impedance, and weakening the mutual coupling between columns, thereby compressing the horizontal radiation divergence angle and ultimately achieving horizontal wavewidth convergence. Attached Figure Description

[0015] Figure 1 This is a top view of a base station antenna disclosed in an embodiment of the present invention after the high-frequency radiating element array has been hidden.

[0016] Figure 2 This is a top view of a base station antenna disclosed in an embodiment of the present invention.

[0017] Figure 3 This is a schematic diagram of a base station antenna according to an embodiment of the present invention, in which a single metal boundary and a PCB boundary are disposed on a reflector.

[0018] Figure 4 This is a schematic diagram of a base station antenna according to an embodiment of the present invention, in which a single metal boundary is disposed on a reflector.

[0019] Figure 5 This is a schematic diagram of a combination structure of a high-frequency radiating element and a double-layer loading sheet in a base station antenna according to an embodiment of the present invention.

[0020] Figure 6 yes Figure 5 The exploded view of the high-frequency radiation unit and the double-layer loading sheet is shown.

[0021] Label Explanation: 1. Reflector; 11. Longitudinal central axis; 2. Low-frequency radiation element array; 21. Unoffset radiation element; 22. First array axis; 23. Offset radiation element; 24. Second array axis; 3. Assembly boundary; 31. Metal boundary; 32. Base plate; 33. Main board; 34. PCB boundary; 4. High-frequency radiation unit array; 41. High-frequency radiation unit; 5. Double-layer loading sheet; 51. First-layer loading sheet; 52. Second-layer loading sheet; 6. First support component; 7. Second support component. Detailed Implementation

[0022] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0023] First, a definition of the terminology used in this application is provided: Base station antennas are key components in mobile communication systems that connect base station equipment to the air interface. They are typically installed on communication towers, rooftops, or high places, and transmit radio frequency signals in a directional manner to the target coverage area through radiating elements, while also receiving uplink signals from user terminals.

[0024] Ultra-wideband multi-port base station antennas are base station antennas that integrate multiple independent radio frequency ports and can simultaneously support multi-band signal radiation and reception within an extremely wide operating frequency band. Through port isolation and multiplexing technology, they can achieve multi-standard, multi-channel common aperture deployment to improve spectrum efficiency and reduce rooftop space occupation.

[0025] Secondly, to facilitate understanding of the technical solutions provided in the embodiments of the present invention by those skilled in the art, the relevant technologies are described below: In the engineering practice of ultra-wideband multi-port base station antennas, the design challenges of different frequency bands vary. The main pain points of base station antennas (such as low-frequency antennas) are: due to the longer wavelength of low-frequency antennas, the physical arrangement spacing of the elements is limited, resulting in a larger horizontal beamwidth and significant phase dispersion within the ultra-wideband bandwidth; at the same time, multi-port antennas also need to consider isolation, and it is not possible to simply increase the array spacing to reduce the horizontal beamwidth (i.e., beamwidth), while reducing the spacing will worsen the isolation.

[0026] Therefore, to achieve horizontal beamwidth convergence, the industry typically employs the following two solutions, as detailed below: Option 1: Linear Array + Bridge Feed Scheme. The overall core structure of Option 1 is as follows: First, its low-frequency radiating elements are arranged in a one-dimensional, equally spaced linear array on the reflector, forming the basic linear array radiating body; second, in its feed network, phase shifters and bridge networks are connected to the radiating elements. The bridge network is usually connected to the end or middle radiating elements of the linear array. Multi-port signals complete the integrated design of power distribution, phase matching, and port isolation through the bridge, thereby reducing horizontal lateral radiation energy, compressing the main lobe radiation angle, directly converging the horizontal wavewidth, and improving its full-band consistency.

[0027] However, the above-mentioned scheme 1 has obvious drawbacks: relying on multi-level broadband bridge topology to achieve amplitude and phase modulation results in a complex power supply link hierarchy and a large overall RF insertion loss; at the same time, the multi-port bridge interconnection wiring topology is complex, which has strict requirements on structural layout and processing accuracy, and is not conducive to antenna lightweight, high integration and low cost design.

[0028] Scheme 2 is a linear array + cross-feeding scheme for oscillators. The overall core structure of Scheme 2 is as follows: First, its low-frequency radiating unit adopts a one-dimensional linear low-frequency oscillator array layout, and the physical arrangement spacing and oscillator shape remain in a conventional design without changing the hardware structure; Second, its feeding network abandons the traditional equal amplitude and in-phase feeding, and adopts cross-staggered phase feeding for adjacent oscillators in the array (for example, phase interleaving excitation of odd and even units, or cross-connection of the oscillator arms of two columns of radiating units). This belongs to the phase reconstruction feeding within the array, and no additional external synthesis network is required.

[0029] However, the above-mentioned Scheme 2 also has obvious drawbacks: the unit feed phase arrangement is fixed, the beam reconstruction degree of freedom is low, and it is impossible to achieve flexible switching and dynamic control of horizontal beamwidth; at the same time, the circuit topology has poor universality, and port isolation management is difficult in large-scale multi-port array applications, and the array expansion adaptability is weak.

[0030] To at least address the aforementioned problems, this invention provides a high- and low-frequency fusion base station antenna solution. This solution includes a low-frequency radiating element array 2 (i.e., two columns of low-frequency radiating elements) and a high-frequency radiating element array 4 (i.e., four columns of high-frequency radiating elements 41). Specifically, based on the non-coaxial design of the two columns of low-frequency radiating elements and the use of a corresponding combined boundary 3 (i.e., metal boundary 31 + PCB boundary 34) between the two columns of low-frequency radiating elements, convergence of the low-frequency horizontal bandwidth can be achieved. Simultaneously, a double-layer loading sheet 5 structure is provided above each high-frequency radiating element 41 in the high-frequency radiating element array 4, which can achieve convergence of the high-frequency horizontal bandwidth. That is, based on the above multiple designs, this solution can simultaneously converge the horizontal bandwidth of both the low-frequency and high-frequency bands.

[0031] It should be noted that the non-coaxial arrangement of the low-frequency radiating elements, the combined boundary 3 in the middle of the low-frequency radiating elements, and the double-layer loading plate 5 on the high-frequency radiating elements 41 all belong to passive field-domain modulation. This achieves bandwidth convergence by reshaping the radiation field by changing the spatial position of the radiating elements, electromagnetic boundaries, and near-field coupling environment. No additional feeding devices are involved, resulting in fewer material types. This effectively simplifies network layout and assembly processes, and shortens the debugging cycle, enabling mass production of products with stronger consistency and higher yield rates. This is beneficial for antenna lightweighting, high integration, and low-cost design. Furthermore, based on the passive structure optimization of the passive field-domain modulation, only the structural design of the antenna body needs to be changed. There is no need to add RF devices such as bridges, power dividers, or phase-matching components. This eliminates the need for complex hierarchical structures and results in lower overall RF insertion loss, avoiding the drawback of high insertion loss. Consequently, network link hierarchical loss is lower, and radiation efficiency is higher. Furthermore, compared to the shortcomings of the cross-feeding scheme, which has a completely fixed phase and cannot flexibly switch the waveform width, this scheme can subsequently fine-tune the waveform width by adjusting the boundary structure size in the combined boundary 3, the spacing and area in the double-layer loading plate 5, and the misalignment offset d7 involved in the non-coaxial arrangement, so as to balance the fixed convergence effect and structural adaptability. At the same time, the above-mentioned fine-tuning can also seamlessly adapt to large-scale multi-port arrays, making the array scalability and port layout compatibility far superior to the cross-feeding scheme.

[0032] The technical solutions according to the present invention will be described below with reference to specific embodiments and in conjunction with the accompanying drawings.

[0033] Figure 1 This is a top view of a base station antenna according to an embodiment of the present invention, with the high-frequency radiating element array 4 hidden. (Refer to...) Figure 1 The base station antenna includes a reflector 1, a low-frequency radiating element array 2, and a combined boundary 3.

[0034] The low-frequency radiation unit array 2 is disposed on the reflector 1. The low-frequency radiation unit array 2 includes two columns of low-frequency radiation units, which are symmetrically arranged along the longitudinal central axis 11 of the reflector 1.

[0035] The combined boundary 3 includes a metal boundary 31 and a PCB boundary 34, which are disposed on the reflector 1. The metal boundary 31 and the PCB boundary 34 are disposed on the same central axis and are both located on the longitudinal central axis 11.

[0036] As can be seen from the above description, the beneficial effects of the present invention are as follows: First, by setting two columns of low-frequency radiation units on the reflector 1 and symmetrically arranging the two columns of low-frequency radiation units along the longitudinal central axis 11 of the reflector 1, a corresponding low-frequency radiation unit array 2 is formed. Based on the above-mentioned low-frequency radiation unit array 2, the present invention sets a combined boundary composed of a metal boundary 31 and a PCB boundary 34 on the central axis 11 of the two columns of low-frequency radiation units (that is, the longitudinal central axis 11 of the reflector 1). Based on this combined boundary 3, the radiation energy that originally diffused to both sides of the horizontal direction can be gathered to the main radiation direction by cutting off surface waves, adjusting the field boundary impedance, and weakening the mutual coupling between columns, thereby compressing the horizontal radiation divergence angle and achieving horizontal wavewidth convergence.

[0037] Specifically: (1) First, because the wavelength of the low-frequency antenna is longer, the radiating elements in the low-frequency radiating element array 2 are very likely to excite transverse surface waves on the reflector 1 and the dielectric plate. The surface waves propagate horizontally to the left and right along the middle region of the two columns of low-frequency radiating elements, directly causing the horizontal radiation range to increase and the wavewidth to diverge. A single homogeneous boundary cannot block the continuous propagation of surface waves. To this end, the present invention sets up a combined boundary 3 composed of two different media to achieve splicing of materials with different dielectric constants and different conductivity characteristics, thereby destroying the continuous uniform waveguide interface required for surface wave propagation, breaking the dispersion propagation condition, directly cutting off the horizontal transverse surface wave transmission path, truncating the low-frequency transverse surface waves, and suppressing the transverse diffusion of horizontal energy. At this time, the transverse spillover energy is locked, and the energy is only radiated in the main normal direction, reducing the horizontal radiation range from the source, thereby effectively achieving horizontal wavewidth convergence. (2) Secondly, since the two columns of low-frequency radiation units in the same frequency band in the low-frequency radiation unit array 2 are close together, the electromagnetic coupling of the same polarization is extremely strong. This electromagnetic coupling of the same polarization will distort the original horizontal radiation pattern of the low-frequency radiation unit, causing horizontal radiation scattering and bandwidth divergence. To this end, the present invention sets a combined boundary 3 between the two columns of low-frequency radiation units in the same frequency band to achieve layered isolation. Layered isolation can weaken the mutual coupling of the two columns of radiation units in the same frequency, correct the horizontal radiation pattern of the unit, and thus alleviate the phenomenon of horizontal radiation scattering and bandwidth divergence, which helps to achieve bandwidth convergence. (3) Furthermore, the combined boundary 3 can achieve gradient electromagnetic isolation: a highly conductive metal structure (i.e., metal boundary 31) is set between the two columns of low-frequency radiation units. Based on this highly conductive metal structure, the near-field electromagnetic coupling energy propagating along the straight path between the two radiation units can be directly blocked (i.e., blocking direct coupling near field); at the same time, a high-low dielectric sandwich structure (i.e., PCB boundary 34) is set between the two columns of low-frequency radiation units. Based on this high-low dielectric sandwich structure, the field penetration coupling can be effectively weakened. Based on this, the metal boundary 31 and the PCB boundary 34 work together to suppress inter-column electromagnetic coupling from the two dimensions of direct coupling and permeation coupling, respectively, forming gradient electromagnetic isolation. After the inter-column coupling is weakened, the inter-column mutual impedance will also decrease accordingly, thereby restoring the independent standard horizontal radiation characteristics of each column of radiation unit, eliminating the radiation distortion caused by coupling, and the beamwidth will converge to the design range.

[0038] It should be noted that the base station antenna of the present invention can be an ultra-wideband multi-port base station antenna. In the present invention, the base station antenna has a low-frequency radiating element array 2 and a high-frequency radiating element array 4 disposed on the reflector 1. The following description, in conjunction with... Figure 1 as well as Figure 2 The above-mentioned reflector 1, low-frequency radiation unit array 2, high-frequency radiation unit array 4, and other optional structures are described in detail.

[0039] The reflector 1 is generally rectangular in shape, such as... Figure 1As shown, the reflector 1 has a longitudinal central axis 11. In practical applications, the horizontal length direction (i.e., the first direction) of the reflector 1 is the same as the extension direction of the longitudinal central axis 11, and the horizontal width direction (i.e., the second direction) of the reflector 1 is perpendicular to the first direction.

[0040] The low-frequency radiation unit array 2 is disposed on the reflector 1, and the low-frequency radiation unit array 2 includes two columns of low-frequency radiation units, which are symmetrically arranged on the reflector 1 along the longitudinal central axis 11. In order to achieve convergence of low-frequency horizontal bandwidth, the low-frequency radiation unit array 2 mainly adopts the following two designs.

[0041] First, the low-frequency radiating unit is designed to be non-coaxial. At least one low-frequency radiation unit in each of the two rows of low-frequency radiation units is offset to both sides of the shaft at the upper end, away from the DIN head, with the offset d7 being 0.04-0.08 times the wavelength of the center frequency point within the low-frequency operating bandwidth.

[0042] Specifically, in some embodiments, such as Figure 1 As shown, each column of low-frequency radiation units includes multiple low-frequency radiation units, and each column of low-frequency radiation units includes at least one unoffset radiation unit 21 and at least one offset radiation unit 23. The at least one unoffset radiation unit 21 is arranged along a first array axis 22, which is parallel to the longitudinal central axis 11 and has a first distance d1 between them. The at least one offset radiation unit 23 is arranged along a second array axis 24, which is parallel to the longitudinal central axis 11 and has a second distance d2 between them. The second distance d2 is greater than the first distance d1.

[0043] It should be noted that the value of the first spacing d1 is 0.32-0.36 times the wavelength of the low-frequency center frequency point, and the difference between the second spacing d2 and the first spacing d1 is 0.04-0.08 times the wavelength of the center frequency point within the low-frequency operating bandwidth. That is, the offset d7 of the offset radiation unit 23 relative to the non-offset radiation unit 21 is 0.04-0.08 times the wavelength of the center frequency point within the low-frequency operating bandwidth.

[0044] In practical applications, such as Figure 1 As shown, each column of low-frequency radiation units includes two offset radiation units 23 and two unoffset radiation units 21. The two offset radiation units 23 are offset outward relative to the two unoffset radiation units 21. The offset radiation units 23 are located on the reflector 1 away from the DIN head, while the unoffset radiation units 21 are located on the reflector 1 closer to the DIN head.

[0045] As described above, the low-frequency radiating element array 2 of the base station antenna adopts a non-coaxial design. Based on this non-coaxial design, the electromagnetic mutual coupling between the subarray and the radiating element can be effectively reduced, the element pattern distortion, array phase disorder and radiation disorder interference caused by coupling can be eliminated, and the convergence of horizontal bandwidth can be effectively achieved. The specific analysis is as follows: First, the non-coaxial design utilizes spatial field attenuation to suppress mutual coupling between array elements. Based on the near-field and far-field propagation characteristics in free space, antenna coupling strength is negatively correlated with the relative azimuth angle and spatial spacing of the array elements. The non-coaxial staggered arrangement increases the principal radiation angle of the elements, offsetting the direct coupling path and separating the strong near-field induction zone. This causes the coupling energy to attenuate rapidly, suppressing mutual coupling between array elements and thus reducing the impact on radiation performance indicators.

[0046] Secondly, the non-coaxial design improves the isolation between polarizations. When dual-polarized base station antennas are arranged coaxially, orthogonal polarization crosstalk is severe; however, the non-coaxial axial offset increases the polarization radiation angle, further reducing the coupling between polarizations, thus lowering the overall coupling level of the entire array and mitigating the performance degradation caused by field interference between radiating elements, thereby effectively improving the isolation between polarizations.

[0047] Next, the non-coaxial design reduces the near-field induced current. In a coaxial layout, adjacent radiating elements are in each other's strong near-field regions, which induces a large amount of additional current; while the non-coaxial layout removes the elements from the strong induction region, sharply reducing the near-field induced current, thus weakening the near-field induced current, and the radiation state of the element itself is no longer affected by the adjacent array.

[0048] Furthermore, non-coaxial design can effectively achieve relative convergence of horizontal beamwidth. A non-coaxial array design increases the relative azimuth angle and spatial distance between array elements. Since antenna coupling strength is negatively correlated with the relative azimuth angle and spatial distance between array elements, a non-coaxial array design can effectively suppress mutual coupling between array elements (i.e., reduce the coupling coefficient). Based on this, since a larger coupling coefficient results in a greater amplitude variation between adjacent radiating elements, the horizontal beamwidth will relatively widen; conversely, a smaller coupling coefficient leads to relative convergence of the horizontal beamwidth. Therefore, when a non-coaxial array design is adopted, the increased relative azimuth angle and spatial distance between array elements reduces the coupling coefficient, thereby achieving horizontal beamwidth convergence.

[0049] Second, the combined boundary 3 of metal boundary 31 and PCB boundary 34. Between the two rows of low-frequency radiating units, a combined boundary 3 using different materials and structures is used. This combined boundary 3 is a metal boundary 31 + a PCB boundary 34. The metal boundary 31 and the PCB boundary 34 are set on the same central axis, and both are located on the longitudinal central axis 11 of the reflector 1.

[0050] The length of the metal boundary 31 is 1-1.5 times the wavelength of the low-frequency center frequency, and the height of the metal boundary 31 is 0.2-0.25 times the wavelength of the low-frequency center frequency. In practical applications, the metal boundary 31 can be fixed to the reflector 1 using plastic rivets or similar means and is located in the middle of the two columns of low-frequency radiating units. It should be noted that because the metal boundary 31 is large, placing it in the position of the high-frequency radiating unit 41 would seriously affect the technical specifications of the high-frequency radiating unit array 4. Therefore, the metal boundary 31 cannot be placed in the middle of the high-frequency radiating unit 41. Furthermore, to prevent short circuits between the metal boundary 31 and the reflector 1, an insulating film is also provided between the metal boundary 31 and the reflector 1 to reduce the possibility of short circuits.

[0051] like Figure 3 as well as Figure 4 As shown, the metal boundary 31 is generally L-shaped. The metal boundary 31 includes a base plate 32 and a main plate 33 connected to each other. The main plate 33 extends vertically, with its bottom resting on the base plate 32. It should be noted that the metal boundary 31 is a metal boundary plate specifically designed for electromagnetic requirements. Utilizing the inherent conductivity of metal, combined with its shape and size, it can constrain, reflect, and directionally guide electromagnetic waves, thereby controlling the propagation path of electromagnetic waves, the radiation range of the antenna, and the distribution of the surrounding electromagnetic field.

[0052] In practical applications, such as Figure 1 as well as Figure 3 As shown, a metal boundary 31 is positioned at the midline of the two columns of offset radiating elements 23. A first gap exists between the metal boundary 31 and the PCB boundary 34, which is 0.18-0.26 times the wavelength of the low-frequency center frequency. It should be noted that the metal boundary 31 is usually a single, continuous line. However, in certain special cases, if the metal boundary 31 needs to be divided into multiple segments, the length of the metal boundary 31 will be equal to the side length of the low-frequency radiating element, and the distance between two metal boundaries 31 will be equal to the distance between two low-frequency radiating elements.

[0053] The PCB boundary 34 is set on the reflector 1, such as Figure 3As shown, the PCB boundary 34 includes a first boundary plate, a second boundary plate, and a third boundary plate connected sequentially and forming a rectangle. The first and third boundary plates are symmetrically arranged on both sides of the second boundary plate, and the width of the first and third boundary plates is smaller than the width of the second boundary plate. This causes the length sides of the first and third boundary plates to be recessed relative to the length side of the second boundary plate, thus forming a plate-shaped PCB boundary 34 with recessed sides. It should be noted that the PCB boundary 34 is a boundary plate made of PCB (Printed Circuit Board), which is a PCB designed to meet specific electromagnetic performance requirements. It can change the propagation speed and wavelength of electromagnetic waves and affect their refraction, reflection, and coupling characteristics by relying on the dielectric constant of the PCB substrate. It also employs an unconventional shape design (such as...). Figure 3 The irregular shape of the PCB is used to disturb and change the transmission path of electromagnetic waves, giving it electromagnetic control capabilities that ordinary PCBs do not have, ultimately helping to achieve horizontal beam convergence.

[0054] In practical applications, each PCB boundary 34 is snapped onto two first support members 6 (such as plastic support members). These two first support members 6 are fixed to the reflector 1 and extend upward, respectively connecting to both sides of the PCB boundary 34. A third gap d3 exists between the bottom of the PCB boundary 34 and the upper surface of the reflector 1, and this third gap d3 is 0.15-0.2 times the wavelength of the low-frequency center point.

[0055] It should be noted that one or more PCB boundaries 34 can be set on the reflector 1, and the length of each PCB boundary 34 is 0.4-0.6 times the wavelength of the low-frequency center frequency. For example, such as Figure 1 as well as Figure 2 As shown, there are two PCB boundaries 34, located at the central axis of the two columns of unoffset radiating units 21, and also at the central axis of the two groups of high-frequency radiating units 41. In practical applications, the number of PCB boundaries 34 used can be determined by the length of the array, wherein the number of PCB boundaries 34 × length ≈ length of the high-frequency radiating unit array 4 (i.e., the overall length of one column of high-frequency radiating units 41). For cases with multiple PCB boundaries 34, a second gap is provided between two adjacent PCB boundaries 34, and the second gap between two adjacent PCB boundaries 34 is 0.13-0.2 times the wavelength of the low-frequency center frequency.

[0056] As described above, a combined boundary 3 of metal boundary 31 and PCB boundary 34 is used between the two columns of low-frequency radiation units. Based on this combined boundary 3, surface waves can be effectively cut off, field boundary impedance can be controlled, and inter-coupling between columns can be weakened. This will gather the radiation energy that was originally diffused to both sides of the horizontal direction to the main radiation direction, compress the horizontal radiation divergence angle, and finally achieve horizontal wavewidth convergence.

[0057] The above content introduces the low-frequency radiation unit array 2. The following mainly introduces the high-frequency radiation unit array 4.

[0058] like Figure 2 As shown, in some embodiments, the high-frequency radiation unit array 4 includes two sets of high-frequency radiation units 41, which are symmetrically arranged along the longitudinal central axis 11. Each set of high-frequency radiation units 41 includes at least one column of high-frequency radiation units 41 arranged in the longitudinal direction.

[0059] Specifically, the high-frequency radiation unit array 4, located near the DIN head on the reflector 1, includes two sets of high-frequency radiation units 41, symmetrically distributed about the longitudinal central axis 11 of the reflector 1. The two rows of high-frequency radiation units 41 located above the longitudinal central axis 11 can be considered the first set of radiation units, and the two rows of high-frequency radiation units 41 located below the longitudinal central axis 11 can be considered the second set of radiation units. In practical applications, such as... Figure 2 As shown, the reflector 1 has four columns of high-frequency radiating units 41 arranged from top to bottom. The two columns of high-frequency radiating units 41 on the top side can be regarded as the first group of radiating units, and the two columns of high-frequency radiating units 41 on the bottom side can be regarded as the second group of radiating units. It should be noted that the four columns of high-frequency radiating units 41 are all coaxially designed, that is, each column of high-frequency radiating units 41 is placed on an array axis; there is a fourth spacing d4 between two adjacent high-frequency radiating units 41 in each column, and the fourth spacing d4 is 0.88-0.95 times the wavelength of the center frequency point of the high-frequency band.

[0060] In practical applications, such as Figure 2 As shown, in each group of high-frequency radiation units 41, there is a fifth spacing d5 between two adjacent columns of high-frequency radiation units 41. This fifth spacing d5 is 1-1.05 times the wavelength of the center frequency point of the high-frequency band; the two closest columns located near the longitudinal central axis 11 (such as...) Figure 2 The second column of high-frequency radiation units 41 and the third column of high-frequency radiation units 41 have a sixth spacing d6, which is 0.8-1 times the wavelength of the center frequency point of the high-frequency band.

[0061] Based on this, in order to facilitate the convergence of horizontal bandwidth in the high-frequency band, the present invention provides a corresponding double-layer loading plate 5 structure on the high-frequency radiation unit 41, the specific structure of which is as follows.

[0062] In some embodiments, such as Figure 5 as well as Figure 6 As shown, a double-layer loading plate 5 is fixedly provided above each high-frequency radiation unit 41. The double-layer loading plate 5 includes a first-layer loading plate 51 and a second-layer loading plate 52 arranged sequentially from bottom to top. There is a gap between the first-layer loading plate 51 and the second-layer loading plate 52, and between the first-layer loading plate 51 and the high-frequency radiation unit 41. The first-layer loading plate 51 and the second-layer loading plate 52 can be either metal loading plates or PCB loading plates. The metal loading plate refers to a loading plate made of metals such as aluminum and copper using traditional processes such as sheet metal stamping and machining. The PCB loading plate is a loading plate formed by etching specific patterns on the surface of a PCB substrate using printed circuit board technology.

[0063] Specifically, the double-layer loading plate 5 is a double-layer guiding structure disposed above the high-frequency radiation unit 41. Since the first layer loading plate 51 and the second layer loading plate 52 in the double-layer loading plate 5 can be either metal loading plates or PCB loading plates, the double-layer loading plate 5 can be entirely metal loading plates, entirely PCB loading plates, or a combination of metal and PCB loading plates. For example, the first layer loading plate 51 can be a PCB loading plate, and the second layer loading plate 52 can be a metal loading plate.

[0064] In some embodiments, such as Figure 5 as well as Figure 6 As shown, the first loading plate 51 and the second loading plate 52 are square in shape and the side length of the first loading plate 51 and the second loading plate 52 is 0.09-0.18 times the wavelength of the high-frequency center point; or, the first loading plate 51 and the second loading plate 52 are circular in shape and the diameter of the first loading plate 51 and the second loading plate 52 is 0.09-0.18 times the wavelength of the high-frequency center point.

[0065] As described above, by setting the size range of the first-layer loading piece 51 and the second-layer loading piece 52, the waveform width can be flexibly adjusted by slightly adjusting the area of ​​the first-layer loading piece 51 and the second-layer loading piece 52, taking into account both the fixed convergence effect and structural adaptability. At the same time, based on the corresponding fine adjustment, it can be seamlessly adapted to large-scale multi-port arrays, so that the array scalability and port layout compatibility are better than the cross-feed scheme.

[0066] In some embodiments, the spacing between the first layer loading sheet 51 and the high-frequency radiation unit 41 is 0.05-0.07 times the wavelength of the high-frequency center frequency; the spacing between the first layer loading sheet 51 and the second layer loading sheet 52 is 0.03-0.06 times the wavelength of the high-frequency center frequency.

[0067] In practical applications, the high-frequency radiation unit 41 is mounted on the reflector 1, and the first layer loading plate 51 and the second layer loading plate 52 are mounted on the high-frequency radiation unit 41 via the second support member 7. Specifically, as follows: Figure 5 as well as Figure 6 As shown, the bottom of the second support member 7 is disposed on the high-frequency radiation unit 41, and extends upward from the high-frequency radiation unit 41. The first layer loading plate 51 and the second loading plate are sequentially mounted on the second support member 7 from bottom to top.

[0068] As can be seen from the above description, by setting the spacing between the first layer loading plate 51 and the high-frequency radiation unit 41, as well as the spacing between the first layer loading plate 51 and the second layer loading plate 52, to the corresponding value range, the wavelength can be flexibly adjusted by fine-tuning the spacing, taking into account both the fixed convergence effect and structural adaptability. At the same time, based on the corresponding fine-tuning, it can be seamlessly adapted to large-scale multi-port arrays, and its array scalability and port layout compatibility are better than the cross-feed scheme.

[0069] In summary, the structure of using a double-layer loading plate 5 above the high-frequency radiation unit 41 is a scheme designed based on top parasitic coupled radiation and near-field electromagnetic boundary constraints. By expanding the equivalent radiation aperture, regularizing the aperture field phase, suppressing the top oblique scattered radiation, and weakening the mutual coupling effect at the top of the unit, it can concentrate the scattered radiation energy towards the main radiation direction, ultimately achieving horizontal wavelength convergence and narrowing. The specific analysis is as follows.

[0070] First, coupled excitation generates parasitic radiation, increasing the equivalent radiation aperture. Due to the limited physical size of the high-frequency radiating element 41, the effective radiation aperture is small and the far-field beam is prone to divergence. Therefore, this invention sets a double-layer loading plate 5 on the high-frequency radiating element 41, enabling near-field coupled excitation of the upper and lower metal loading plates, inducing a synchronous radiation current in the same direction on the double-layer loading plate 5, forming a passive parasitic radiation element. Based on this, the double-layer loading plate 5 can achieve the following effects: First, the double-layer structure of the double-layer loading plate 5 can expand the vertical and horizontal equivalent radiation area of ​​the antenna. According to the aperture radiation formula, the beamwidth is inversely proportional to the equivalent radiation aperture; increasing the aperture directly compresses the beam divergence angle. Second, the double-layer arrangement of the double-layer loading plate 5 can form a gradient current distribution, making the aperture field distribution of the entire radiation surface more uniform, the beam shape more regular, and avoiding main lobe distortion.

[0071] Secondly, the spacing between the two layers of the double-layer loading plate 5 can create a phase difference, optimizing the convergence beam of the space radiation interference. The double-layer loading plate 5 has a fixed air or medium spacing, which generates a controllable electrical length phase difference for high-frequency electromagnetic waves. This phase difference changes the beamwidth, as follows: First, in the main radiation direction: the combination of the main radiation unit and the double-layer loading plate 5 causes the radiation waves to superimpose in phase, enhancing the main lobe energy; second, in the lateral and oblique upward stray directions, the radiation waves form phase cancellation, significantly suppressing unwanted radiation. Based on this, energy is gathered through directional constructive interference, and lateral destructive interference suppresses stray waves, rapidly tightening the beam angle, thereby optimizing the convergence beam of the space radiation interference.

[0072] Furthermore, the double-layer loading plate 5 structure can constrain the near-field at the top and block high-frequency oblique spillover radiation. In practical applications, due to the extremely strong diffraction and scattering effects of high-frequency electromagnetic waves, the top of the high-frequency radiation unit 41 is prone to spilling electromagnetic energy obliquely upwards and to the side, directly widening the wavelength and raising the sidelobes. The double-blocking based on the double-layer loading plate 5 structure forcibly constrains the originally scattered energy to the normal main radiation direction, compressing the radiation range in space. Specifically, the first layer loading plate 51 is close to the top of the high-frequency radiation unit 41, gathering the original near-field of the oscillator and limiting the outward diffusion of the field; the second layer loading plate 52 forms a top-level electromagnetic shielding barrier, blocking the direct spillover radiation at the top.

[0073] In summary, the base station antenna according to the present invention: (1) The horizontal bandwidth of the low-frequency band and the high-frequency band can achieve effective convergence of 5°~10° respectively, and improve the consistency of the horizontal bandwidth. (2) The non-coaxial arrangement + heterogeneous material and heterostructure combination boundary 3 in the low-frequency radiating unit array 2 and the double-layer loading plate 5 structure on the high-frequency radiating unit 41 are both passive field-domain modulation. They rely on changing the spatial position of the radiating unit, the electromagnetic boundary and the near-field coupling environment to reshape the radiation field, which can effectively achieve bandwidth convergence. There is no additional feeding device involved, fewer types of materials, simplified network layout and assembly process, shorter debugging cycle, stronger consistency in mass production and higher yield of mass production. (3) Low network link layer loss and higher radiation efficiency: The passive structure optimization only changes the structural design of the antenna body, without adding RF devices such as bridge, power divider and phase matching, resulting in lower insertion loss of the whole machine and avoiding the defect of large insertion loss. (4) The combined boundary 3 in the low-frequency radiation unit and the double-layer loading plate 5 on the top of the high-frequency radiation unit 41 are both broadband electromagnetic structure schemes. They can uniformly suppress surface waves, lateral scattering radiation and inter-array coupling in the ultra-wide frequency range, resulting in good convergence consistency of high and low frequency beams. (5) Compared with the shortcomings of the existing cross-feed scheme of oscillators, which has completely fixed phase and cannot flexibly switch the wave width, the present invention can adjust the wave width slightly and flexibly by finely adjusting the structural size of the boundary (such as metal boundary 31, PCB boundary 34), the spacing and area of ​​the loading plates and the offset d7, so as to take into account both the fixed convergence effect and the structural adaptability. At the same time, it can be seamlessly adapted to large-scale multi-port arrays. Its array scalability and port layout compatibility are better than the cross-feed scheme. (6) Better mutual coupling suppression: Based on the above design, it is possible to achieve near-field spatial field isolation and directly weaken the electromagnetic coupling between units based on the field truncation level. It belongs to the root cause of coupling suppression, while the feeding scheme only improves the coupling effect by optimizing the amplitude and phase at the circuit level, which cannot completely eliminate the near-field native coupling interference. The present invention has a more thorough isolation effect. (7) Most conventional base station antennas adopt coaxial arrays, that is, all radiating elements in a column are aligned along the same central axis. This layout makes the radiation fields of the array elements highly overlapped, which enhances the electromagnetic coupling between the elements. The resulting induced current, energy crosstalk and field strength interference will lead to the deterioration of the array radiation performance index. To address this problem, the base station antenna array in this invention adopts a non-coaxial arrangement design, which can effectively reduce the electromagnetic mutual coupling between subarrays and elements, eliminate the element pattern distortion, array phase disorder and radiation disorder interference caused by coupling, and achieve convergence of horizontal wavewidth. (8) Based on the combined boundary, splicing, concave and convex, choke and stepped irregular structures of materials with different dielectric constants and different conductivity properties are realized, which destroys the continuous uniform waveguide interface required for surface wave propagation, breaks the dispersion propagation condition, and directly cuts off the horizontal transverse surface wave transmission path; at the same time, the transverse spillover energy is locked, and the energy is only radiated in the main normal direction, which reduces the horizontal radiation range from the source.

[0074] It should be understood that the terms "first," "second," etc., are used in this invention to describe various types of information, but these terms are not limited to them and are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information.

[0075] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A base station antenna, characterized in that, Includes reflectors, low-frequency radiation element arrays, and combined boundaries; The low-frequency radiation unit array is disposed on the reflector plate, and the low-frequency radiation unit array includes two columns of low-frequency radiation units, which are symmetrically arranged along the longitudinal central axis of the reflector plate. The combined boundary includes a metal boundary and a PCB boundary, which are disposed on the reflector and located on the longitudinal central axis. The metal boundary and the PCB boundary are arranged along the same central axis.

2. The base station antenna according to claim 1, characterized in that, Each column of low-frequency radiating elements includes at least one unoffset radiating element and at least one offset radiating element. The at least one unoffset radiating element is arranged along a first array axis, which is parallel to the longitudinal central axis and has a first gap between them. The at least one offset radiating element is arranged along a second array axis, which is parallel to the longitudinal central axis and has a second gap between them. The second gap is greater than the first gap.

3. The base station antenna according to claim 1, characterized in that, It also includes a high-frequency radiation unit array, which includes multiple high-frequency radiation units. Each high-frequency radiation unit is fixedly provided with a double-layer loading plate above it. The double-layer loading plate includes a first layer loading plate and a second layer loading plate arranged sequentially from bottom to top. There is a gap between the first layer loading plate and the second layer loading plate, and between the first layer loading plate and the high-frequency radiation unit.

4. The base station antenna according to claim 3, characterized in that, The first and second loading sheets are either metal loading sheets or PCB loading sheets.

5. The base station antenna according to claim 3, characterized in that, The spacing between the first layer of loading sheet and the high-frequency radiation unit is 0.05-0.07 times the wavelength of the high-frequency center frequency; the spacing between the first layer of loading sheet and the second layer of loading sheet is 0.03-0.06 times the wavelength of the high-frequency center frequency.

6. The base station antenna according to claim 3, characterized in that, The first and second loading plates are square in shape and their side lengths are 0.09-0.18 times the wavelength of the high-frequency center point; or, the first and second loading plates are circular in shape and their diameters are 0.09-0.18 times the wavelength of the high-frequency center point.

7. The base station antenna according to claim 3, characterized in that, The high-frequency radiation unit array includes two sets of high-frequency radiation units, which are symmetrically arranged along the longitudinal central axis. Each set of high-frequency radiation units includes at least one column of high-frequency radiation units arranged along the longitudinal direction.

8. The base station antenna according to claim 1, characterized in that, There is a third gap between the bottom of the PCB boundary and the upper surface of the reflector, the third gap being 0.15-0.2 times the wavelength of the low-frequency center point.

9. The base station antenna according to claim 1, characterized in that, It also includes an insulating film disposed between the metal boundary and the reflector.

10. The base station antenna according to claim 1, characterized in that, The length of the metal boundary is 1-1.5 times the wavelength of the low-frequency center point, and the height of the metal boundary is 0.2-0.25 times the wavelength of the low-frequency center point.

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