Multi-beam sector split base station antenna with compact beamforming network

Abstract

The invention relates to a multi-beam sector split base station antenna with a compact beamforming network. The multi-beam base station antenna comprises: an antenna array comprising a plurality of columns of radiating elements; and a beamforming network having at least two rows and two columns of directional couplers, where adjacent pairs of directional couplers in each row are connected to each other by respective ones of a plurality of delay lines, where at least some of the delay lines have a wave shape comprising a plurality of peaks and valleys.

Description

Technical Field

[0001] This invention generally relates to radio communications, and more specifically, to multi-beam sector split base station antennas used in cellular and other communication systems. Background Technology

[0002] Cellular communication systems are well known in the art. In a typical cellular communication system, a geographical area is divided into a series of areas called “cells,” each served by a base station. A base station may include baseband equipment, a radio, and a base station antenna configured to provide bidirectional radio frequency (“RF”) communication with users located throughout the cell. In many cases, a cell may be divided into multiple “sectors” in an azimuth plane (a horizontal plane that bisects the antenna and is parallel to the plane defined by a horizontal line), and a separate base station antenna provides coverage for each sector. Base station antennas are typically mounted on towers or other elevated structures, and the radiation pattern (“antenna beam”) generated by the antenna is pointed outwards to provide service to the corresponding sector.

[0003] A common base station configuration is a "three-sector" configuration, where the cell is divided into three 120° sectors in the azimuth plane, and the base station includes three base station antennas providing coverage of the three corresponding sectors. Typically, each base station antenna will include one or more vertically extending columns of radiating elements, each column configured to generate a separate antenna beam (or, if dual-polarized radiating elements are used, two antenna beams, as well well understood in the art). Each column of radiating elements is connected to a feed network that subdivides the RF signal and feeds each sub-component of the RF signal to a corresponding subset of one or more radiating elements in the column. Typically, each radiating element is configured to generate a radiation pattern with a half-power beamwidth ("HPBW") of approximately 65° in the azimuth plane, which ensures good coverage of the antenna beam across the entire 120° sector. The subcomponents of the RF signal are phased, such that the radiation patterns generated by each subset of one or more radiating elements are constructively combined to produce a composite antenna beam with a narrowed HPBW (e.g., 15°–30°) in the elevation (vertical) plane.

[0004] As capacity demands increase, cellular network operators are now dividing some cells into more than three sectors. For example, a cell can now be divided into six, nine, twelve, fifteen, or eighteen sectors in the azimuth plane. Typically, when a cell is divided into more than three sectors, a multi-beam “sector-split” antenna is used. A multi-beam sector-split antenna refers to a base station antenna that generates multiple antenna beams (each polarization) with a narrowing beamwidth in the azimuth plane (i.e., less than about 65° and typically less than about 35° azimuth HPBW), wherein the pointing directions of the multiple antenna beams are designed to split the sector into multiple sub-sectors. This allows a single base station antenna to generate multiple antenna beams (each polarization) providing coverage of the corresponding sub-sectors of a 120° sector.

[0005] For example, a six-sector base station will divide each 120° sector into two 60° sub-sectors in the azimuth plane. This six-sector base station is typically served by three base station antennas, each implemented as a "dual-beam" antenna. These dual-beam antennas are designed to generate a first antenna beam and a second antenna beam (each polarized) providing coverage of the corresponding first and second 60° sub-sectors of each 120° sector. Each antenna beam may have an HPBW of approximately 30-35° in the azimuth plane. The first antenna beam may be pointed at an angle of approximately -27° to -30° from the antenna's line-of-sight direction in the azimuth plane, and the second antenna beam may be pointed at an angle of approximately 27° to 30° from the antenna's line-of-sight direction in the azimuth plane. The line-of-sight direction of the antennas is the center of the 120° sector served by the antennas in the azimuth plane. In this way, the 120° sector is divided into two 60° sub-sectors covered by the corresponding first and second antenna beams.

[0006] Providing cellular service in large venues such as stadiums, arenas, convention centers, and concert halls can be particularly challenging because a very large number of users may be located in a very small area. In such venues, multi-beam sector-split base station antennas can be used, each generating three or more antenna beams per polarization, where each antenna beam provides coverage of a corresponding 20°–40° (or smaller) sub-sector in the azimuth plane. When a 120° sector is subdivided into sub-sectors, system capacity can be significantly increased because the RF energy of each antenna beam is focused into a smaller area, thus providing higher antenna gain.

[0007] To generate an antenna beam with a narrowing beamwidth in the azimuth plane, multi-beam sector-split base station antennas typically include at least one multi-column antenna array. This is because transmitting RF signals through multiple columns of radiating elements expands the antenna aperture in the azimuth plane, thus reducing the azimuth beamwidth of the generated antenna beam. For example, dual-beam antennas typically use three- or four-column arrays of radiating elements. While a separate multi-column array of radiating elements could be used to generate each antenna beam, this approach is generally not commercially acceptable because it produces very large and expensive antennas. Therefore, multi-beam antennas typically include a beamforming network that allows multiple RF signals to be transmitted through a single multi-column array of radiating elements to generate multiple corresponding antenna beams pointing in different directions.

[0008] Multi-beam sector-splitting antennas comprising multiple RF ports (each polarization) are known in the art, the multiple RF ports being coupled to a multi-column array of radiating elements via a Butler matrix beamforming network. The beamforming network generates multiple antenna beams (each polarization) based on RF signals input at the multiple RF ports, and the antenna beams are electrically deflected such that each antenna beam provides coverage of a different sub-sector, for example, a 120° sector. Additionally, multi-beam sector-splitting antennas using Blass or Nolen matrix beamforming networks are known in the art. Summary of the Invention

[0009] According to an embodiment of the present invention, a multi-beam sector-split base station antenna is provided, the multi-beam sector-split base station antenna comprising: an antenna array including multiple columns of radiating elements; and a beamforming network having at least two rows and two columns of directional couplers, wherein adjacent directional coupler pairs in each row are connected to each other by corresponding delay lines of a plurality of delay lines, wherein at least some of the delay lines have a waveform including multiple peaks and valleys.

[0010] In some embodiments, the antenna array may include N columns of radiating elements and a plurality of RF ports coupled to the antenna array via the beamforming network. The beamforming network may have M rows and N columns of directional couplers. In some embodiments, each row of the beamforming network may have a different number of directional couplers (e.g., Blass matrix embodiment). In other embodiments, each row of the beamforming network may have the same number of directional couplers (e.g., Nolen matrix embodiment).

[0011] In some embodiments, the multi-beam antenna may further include a reflector, and the radiators of the radiating elements of the antenna array may be mounted in front of the reflector, and the beamforming network may also be mounted in front of the reflector 102. In some embodiments, the beamforming network may be implemented in a printed circuit board, and the printed circuit board may be mounted on the front surface of the reflector. In some embodiments, at least some of the radiating elements fed by the beamforming network may be mounted on the printed circuit board.

[0012] In some embodiments, the first axis intersects all directional couplers in the first row and at least one directional coupler that is part of the second row. Furthermore, the first distance between the first directional coupler and the last directional coupler in the first row may be less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

[0013] In some embodiments, the beamforming network may be implemented in a beamforming network printed circuit board mounted behind the reflector of the base station antenna, and the beamforming network printed circuit board may include tabs extending through openings in the reflector to electrically connect to a subset of the radiating elements. In such embodiments, the multi-beam antenna may further include a plurality of feed board printed circuit boards mounted in front of the reflector, wherein each tab in the beamforming network printed circuit board extends through a slot in a corresponding feed board printed circuit board. In some embodiments, the beamforming network printed circuit board may be mounted substantially perpendicular to the main surface of the reflector.

[0014] According to another embodiment of the present invention, a multi-beam sector-split base station antenna is provided, the multi-beam sector-split base station antenna comprising: an antenna array including multiple rows of radiating elements; and a printed circuit board including: a plurality of feed plate regions; a first beamforming region including a first beamforming network including a plurality of directional couplers and a plurality of outputs; and a plurality of transmission lines connecting at least some of the outputs of the beamforming network to corresponding feed plate regions in the feed plate regions, wherein each feed plate region has one or more radiating elements of the antenna array mounted thereon.

[0015] In some embodiments, the multipurpose printed circuit board may further include a second beamforming region, the second beamforming region including a second beamforming network, and at least some of the feed board regions are located between the first beamforming region 560-1 and the second beamforming region. In some embodiments, the transmission line may be a microstrip transmission line.

[0016] In some embodiments, one or more beamforming networks may include a Blass matrix or a Nolen matrix. In some embodiments, at least one output of the beamforming network is connected to a feed board printed circuit board via a coaxial cable. In such embodiments, at least one radiating element that is part of an outer column of the radiating elements is mounted on the feed board printed circuit board.

[0017] In some embodiments, the beamforming network has at least two rows and two columns of directional couplers, wherein adjacent directional coupler pairs in each row are connected to each other by corresponding delay lines of a plurality of delay lines, wherein at least some of the delay lines have a wave shape including a plurality of peaks and valleys.

[0018] In some embodiments, the first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row. In some embodiments, a first distance between the first directional coupler and the last directional coupler in the first row is less than a second distance between the first directional coupler and the penultimate directional coupler in the second row.

[0019] In some embodiments, the multi-beam antenna may further include a reflector, and the radiator of the radiating element and the beamforming network may be mounted in front of the reflector.

[0020] According to another embodiment of the present invention, a multi-beam sector-split base station antenna is provided, the multi-beam sector-split base station antenna comprising: a reflector; an antenna array including multiple rows of radiating elements, wherein the radiating elements extend forward from the reflector; and a beamforming network printed circuit board mounted behind the reflector, the beamforming network printed circuit board including tabs extending through openings in the reflector to be electrically connected to a subset of the radiating elements.

[0021] In some embodiments, the multi-beam antenna further includes a plurality of feedboard printed circuit boards mounted in front of the reflector, wherein each tab in the beamforming network printed circuit board can extend through a slot in a corresponding feedboard printed circuit board.

[0022] In some embodiments, the beamforming network printed circuit board may be mounted substantially perpendicular to the main surface of the reflector.

[0023] In some embodiments, the first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row. In some embodiments, a first distance between the first directional coupler and the last directional coupler in the first row is less than a second distance between the first directional coupler and the penultimate directional coupler in the second row.

[0024] In some embodiments, the beamforming network further includes multiple delay lines, and adjacent directional coupler pairs in each row are connected to each other by corresponding delay lines in the delay lines. In some embodiments, at least one delay line has a wave shape comprising multiple peaks or multiple valleys.

[0025] In some embodiments, the beamforming network printed circuit board includes a matrix of directional couplers. In some embodiments, the matrix of directional couplers includes a Blass matrix or a Nolen matrix.

[0026] According to further embodiments of the present invention, a multi-beam antenna is provided, comprising: an antenna array; and a beamforming network having a plurality of directional couplers interconnected by a plurality of transmission lines to define multiple rows and columns of directional couplers. The directional couplers in the beamforming network are arranged such that a first axis intersects with all directional couplers in a first row and at least one directional coupler that is part of a second row.

[0027] In some embodiments, the beamforming network includes at least three rows of directional couplers and at least four columns of directional couplers. In some embodiments, a second axis perpendicular to the first axis intersects with the first directional coupler in each row. In some embodiments, a first distance between the first directional coupler in the first row and the last directional coupler is less than a second distance between the first directional coupler in the second row and the penultimate directional coupler.

[0028] According to other embodiments of the present invention, a multi-beam antenna is provided, comprising: an antenna array; and a beamforming network having a plurality of directional couplers interconnected by a plurality of transmission lines to define multiple rows and columns of directional couplers. A first distance between a first directional coupler and the last directional coupler in a first row is less than a second distance between a first directional coupler and the penultimate directional coupler in a second row. In some embodiments, the transmission lines in the first row are straight transmission lines, and the transmission lines in the last row are zigzag transmission lines. Attached Figure Description

[0029] Figure 1A This is a schematic block diagram of a multi-beam sector split base station antenna according to an embodiment of the present invention.

[0030] Figure 1B To show in more detail Figure 1A A schematic block diagram of the feed network for a multi-beam sector split antenna.

[0031] Figure 1C It is shown Figure 1B A schematic block diagram of an exemplary Blass matrix implementation of a beamforming network.

[0032] Figure 2A This is a side view of a printed circuit board implementation of a conventional Blass matrix beamforming network.

[0033] Figure 2B It includes Figure 2A A mosaic of planar (top view) views of each metallization layer of a printed circuit board.

[0034] Figure 2C It includes Figure 2A-2B Rear view of a conventional multi-beam sector split base station with multiple Blass matrix printed circuit boards, where the antenna radome has been removed.

[0035] Figure 2D Two are installed on the corresponding heat sink. Figure 2A-2B A schematic perspective view of a Blass matrix printed circuit board.

[0036] Figure 3A This is a side view of a printed circuit board embodiment of a Blass matrix beamforming network according to an embodiment of the present invention.

[0037] Figure 3B It includes Figure 3A A mosaic of planar (top view) views of each metallization layer of a printed circuit board.

[0038] Figure 3C yes Figure 3B A magnified view of a small portion.

[0039] Figure 3D These are directional couplers with different layouts. Figures 3A-3B A plan view of an alternative printed circuit board implementation of the Blass matrix beamforming network.

[0040] Figure 3E According to an embodiment of the present invention, it includes twenty Figures 3A-3BRear view of a multi-beam sector split base station antenna on a Blass matrix printed circuit board.

[0041] Figure 4A It is a plan view of a multipurpose printed circuit board including two Blass matrix beamforming networks and eight feed boards implemented therein.

[0042] Figure 4B This is the use of ten according to another embodiment of the present invention. Figure 4A A schematic block diagram of a multi-beam sector split base station antenna implemented on a multi-purpose printed circuit board.

[0043] Figure 5A This is a schematic partial view of a multi-beam sector-split base station antenna according to another embodiment of the present invention.

[0044] Figure 5B yes Figure 5A A perspective rear view of a portion of the antenna.

[0045] Figure 6 This is a plan view of several printed circuit boards of a multi-beam sector split base station antenna according to another embodiment of the present invention. Detailed Implementation

[0046] As discussed above, multi-beam sector-splitting base station antennas using Blass or Nolen matrix beamforming networks are known in the art. These multi-beam sector-splitting base station antennas can have performance advantages over those using Butler matrix beamforming networks because Butler matrix beamforming networks can generate antenna beams with a wider azimuth beamwidth than desired, which reduces antenna gain and increases interference between sub-sectors and to adjacent sectors. Furthermore, multi-beam sector-splitting base station antennas using Butler matrix beamforming networks also suffer from what is known as "beampeak walking," a phenomenon where the azimuth pointing angle of each antenna beam shifts according to the frequency of the input RF signal. This beampeak walking not only affects the pointing direction of the antenna beam but also alters the beamwidth and beamform. These effects are undesirable because they mean that the area covered by the corresponding antenna beam may vary significantly with frequency.

[0047] Multi-beam sector split base station antennas using Blass or Nolen matrix beamforming networks typically exhibit very little or no beam peak travel and can generate antenna beams with more appropriate azimuth beamwidths. However, both Blass and Nolen matrix beamforming networks unfortunately include a large number of directional couplers, and since ten to twenty-five such beamforming networks are typically used in an antenna, they can occupy a significant amount of space and be expensive to manufacture. Additionally, these beamforming networks include resistive terminals that absorb some RF energy, which can lead to very high temperatures at the transmit power levels used by the base station antenna, potentially damaging components of the base station antenna.

[0048] According to embodiments of the present invention, a multi-beam base station antenna with an improved beamforming network is provided, which can be smaller and less expensive than conventional beamforming networks. Base station antennas incorporating these beamforming networks can also eliminate the need for a large amount of coaxial cable, which can reduce the weight of the antenna, and can eliminate the need for dozens or even hundreds of solder joints. Since forming solder joints is a labor-intensive operation, and since poorly formed solder joints are a potential source of passive intermodulation (“PIM”) distortion, base station antennas according to embodiments of the present invention can also be lighter and easier to manufacture than conventional antennas, and may be less prone to PIM distortion. Furthermore, in some embodiments disclosed herein, the beamforming network can dissipate heat generated in the resistive terminals more efficiently. Multi-beam base station antennas according to embodiments of the present invention can be implemented using, for example, Blass matrix or Nolen matrix beamforming networks.

[0049] The beamforming networks according to embodiments of the present invention can be implemented using printed circuit boards, and therefore may be referred to herein as, for example, Blass matrix printed circuit boards and Nolen matrix printed circuit boards. As known in the art, a Blass matrix is ​​a beamforming network comprising multiple rows and columns of directional couplers connected by transmission lines, and a Nolen matrix is ​​also a beamforming network comprising multiple rows and columns of directional couplers connected by transmission lines, but the number of directional couplers provided may vary in different rows. Delay elements are included in the Blass and Nolen matrices along selected transmission lines, typically formed by bending the transmission lines such that the transmission lines act as both transmission lines and delay elements.

[0050] According to embodiments of the invention, a beamforming network based on Blass and Nolen matrices is provided, wherein the spacing between adjacent row directional couplers is significantly reduced compared to beamforming networks based on conventional Blass and Nolen matrices. These reduced spacings can be achieved by implementing some of the delay elements as transmission line segments having a waveform comprising multiple peaks and valleys. Using such delay elements can increase the size of the Blass or Nolen matrix printed circuit board in the length dimension, but can also allow for a more significant reduction in the width dimension. This method can, for example, reduce the area of ​​the Blass or Nolen matrix printed circuit board by 50% or more.

[0051] In other embodiments of the invention, a multi-beam sector-splitting base station antenna is provided, comprising a multi-purpose printed circuit board (PCB) including a pair of beamforming networks and a feed board circuit for multiple radiating elements. By implementing both the beamforming networks and the feed board circuit on a common PCB, the need for cable connections between the beamforming network PCB and the feed board PCB can be reduced or eliminated, as these connections can be made instead using PCB-based RF transmission lines. Since a single cable connection between the beamforming network PCB and the feed board PCB may require up to four solder joints (i.e., a first pair of solder joints connecting the center conductor of the coaxial cable to the respective PCB and a second pair of solder joints connecting the ground conductor of the coaxial cable to the respective PCB), hundreds of solder joints are required in a typical conventional multi-beam sector-splitting base station antenna to connect the beamforming network PCB to the feed board PCB. The base station antenna according to embodiments of the invention can eliminate the need for some or all of these solder joints. Furthermore, the multi-purpose PCB is mounted on the front side of the reflector, which saves space behind the reflector and allows for more efficient dissipation of heat generated in the beamforming network.

[0052] According to other embodiments of the invention, a multi-beam sector-split base station antenna is provided, having a beamforming network printed circuit board mounted behind a reflector of the antenna. These beamforming network printed circuit boards include tabs extending through openings in the reflector for physical and electrical connection to corresponding feed board printed circuit boards. The feed board printed circuit board may be mounted on the front side of the reflector, and the beamforming network printed circuit board may extend perpendicular to both the reflector and the feed board printed circuit board. By directly physically and electrically connecting the beamforming network printed circuit board to the feed board printed circuit board, the need for coaxial cable connections can be eliminated.

[0053] Embodiments of the invention will now be discussed in more detail with reference to the accompanying drawings.

[0054] Figure 1A This is a schematic block diagram of a multi-beam sector-split base station antenna 100 according to an embodiment of the present invention. Figure 1A As shown, the multi-beam sector-split base station antenna 100 includes six RF connector ports 110-1 to 110-6 (also referred to herein as "RF ports") for inputting RF signals from one or more radio devices, such as remote radio heads, into the base station antenna 100. In this document, when multiple identical elements are included in the antenna, these elements may be individually referred to by their full reference numerals (e.g., RF connector port 110-2) and collectively by the first part of their reference numerals (e.g., RF connector port 110). RF connector ports 110-1 to 110-16 may include, for example, RF connectors and may be connected to the RF ports on one or more radio devices via, for example, a coaxial cable. The radio devices are typically located outside the antenna 100 and... Figure 1A Not shown in the image.

[0055] Antenna 100 also includes an antenna array 120 having multiple rows 122 of dual-polarized radiating elements 124 mounted to extend forward from reflector 102. Reflector 102 may include a flat metallic surface that acts as a ground plane for the radiating elements 124 and can redirect RF radiation emitted backward by the radiating elements 124 forward. In the depicted embodiment, the antenna includes a total of six rows 122-1 to 122-6 of radiating elements 124, and antenna 100 is configured to feed antenna array 120 such that the antenna array will generate three antenna beams (at each polarization) serving three corresponding 40° sub-sectors in the azimuth plane. Each row 122 of radiating elements 124 may extend vertically, and the rows 122 may be horizontally spaced apart to form a planar array 120 of radiating elements 124. However, it should be understood that in other embodiments, different numbers of rows 122 may be provided, and / or antenna 100 may be configured to generate different numbers of antenna beams.

[0056] In the depicted embodiment, each column 122 includes twenty radiating elements 124. However, it should be understood that in other embodiments, each column 122 may include a different number of radiating elements 124. Each dual-polarized radiating element 124 includes a first polarized radiator 126-1 and a second polarized radiator 126-2. A pair of feed networks (one for each polarization) 130-1, 130-2 are provided to connect the RF port 110 to the antenna array 120. Each feed network 130-1, 130-2 includes multiple beamforming networks (“BFN”) 140. The sector-split antenna 100 can divide 120° in an azimuth plane sector into three 40° sub-sectors in the azimuth plane, thereby providing a separate antenna beam (per polarization) for each sub-sector.

[0057] In an exemplary embodiment, each beamforming network 140 may be implemented as a 3×6 Blass matrix. Three first polarized RF connector ports 110-1 to 110-3 are connected to the three inputs of the first Blass matrix 140-1, and three second polarized RF connector ports 110-4 to 110-6 are connected to the three inputs of the second Blass matrix 140-2. The six outputs of the first Blass matrix 140-1 are connected to the corresponding columns 122 of the six-column antenna array 120, and the six outputs of the second Blass matrix 140-2 are connected to the corresponding columns 122 of the six-column antenna array 120.

[0058] Figure 1B This is a schematic block diagram showing in more detail how the feed networks 130-1 and 130-2 connect RF ports 110-1 to 110-6 to the antenna array 120. Figure 1B The diagram shows only six rows of radiating elements out of twenty rows of radiating elements 124 in the antenna array 120 and only six beamforming networks out of twenty beamforming networks 140 for simplification.

[0059] like Figure 1B As shown, the first power supply network 130-1 includes three phase shifter assemblies 132-1 to 132-3, respectively connected to the first RF port 110-1 to the third RF port 110-3. Figure 1BThe second and third phase shifter assemblies 132-2 and 132-3 (and the fifth and sixth phase shifter assemblies 132-5 and 132-6, discussed below) are shown on a single drawing using small blocks to represent the feed network 130-1. Each phase shifter assembly 132 includes ten outputs. Each phase shifter assembly 132 is configured to receive RF signals from a corresponding RF port in RF port 110 and subdivide these RF signals into ten sub-components. Each phase shifter assembly 132 is also configured to impart a variable phase taper to the ten sub-components, which imparts an electronic downtilt to the generated antenna beam of the desired amount. Phase shifters that can impart such an electronic downtilt, such as electromechanical phase shifters, are well known in the art, and therefore will not be discussed further in this document. The phase shifter assembly 132 can be controlled via control signals, allowing the amount of electronic downtilt to be changed from a remote location. As is known in the art, adjusting the amount of applied electronic downtilt controls the size of the coverage area of ​​the antenna array 120 in the elevation plane.

[0060] like Figure 1B As shown, each output 134 of the phase shifter assembly 132-1 is coupled to a corresponding input 142 of a corresponding beamforming network in beamforming networks 140-1 to 140-10. Because Figure 1B Only three first polarization beamforming networks, 140-1, 140-6, and 140-10, are shown in the figure, therefore... Figure 1B The diagram explicitly shows only three actual connections between phase shifter assembly 132-1 and the first polarization beamforming networks 140-1 to 140-10. The other outputs 134 of phase shifter assembly 132-1 are labeled to indicate how these outputs 134 are connected to the other beamforming networks 140. Phase shifter assemblies 132-2 and 132-3 also each have ten outputs 134, which are coupled to the inputs 142 of the respective first polarization beamforming networks 140-1 to 140-10. Therefore, each of the first polarization beamforming networks 140-1 to 140-10 includes a first input 142 connected to a corresponding output 134 of phase shifter assembly 132-1, a second input 142 connected to a corresponding output 134 of phase shifter assembly 132-2, and a third input 142 connected to a corresponding output 134 of phase shifter assembly 132-3. Phase shifter assemblies 132-4 to 132-6 also each have ten outputs 134, each coupled in the same manner to the inputs 142 of the second polarization beamforming networks 140-11 to 140-20. Figure 1B The lines connecting the outputs 134 of phase shifter assemblies 132-2, 132-3, 132-5, and 132-6 to beamforming networks 140-1 to 140-20 are omitted, but labels are provided to indicate how these components are interconnected.

[0061] Each beamforming network 140 has six outputs 144. Each output 144 is connected to a feed board printed circuit board 128, which includes two radiating elements 124 of the antenna array 120. The feed board printed circuit board 128 couples the outputs 144 of beamforming networks 140-1 to 140-10 to a first polarized radiator 126-1 of the radiating elements 124 in the antenna array 120, and the feed board printed circuit board 128 also couples the outputs 144 of beamforming networks 140-11 to 140-20 to a second polarized radiator 126-2 of the radiating elements 124 in the antenna array 120.

[0062] Figure 1C It is shown Figure 1B A schematic block diagram of an exemplary embodiment of a beamforming network 140. Figure 1C In the embodiment shown, the beamforming network 140 is implemented as a 3×6 Blass matrix 140. The Blass matrix 140 includes a first input 142-1 to a third input 142-3, which are referenced above. Figure 1B The described method connects to the first corresponding outputs of the first phase shifter assembly 132-1 to the third phase shifter assembly 132-3. The Blass matrix 140 includes first outputs 144-1 to sixth outputs 144-6 connected to six feed plates 128. For the context, in Figure 1C The diagram shows six feed plates 128 (each with a radiating element 124). For example... Figure 1C As shown, each feed plate 128 having radiating elements 124 is part of a different column 122 of radiating elements 124, and the feed plate 128 shown forms two rows of radiating elements 124 in the antenna array 120.

[0063] Still referencing Figure 1C The Blass matrix 140 includes three rows and six columns of directional couplers 150, which feed first polarized radiators 126-1 of two rows of radiating elements 124 in, for example, a six-column antenna array 120. It should be understood that, since the dual-polarized radiating elements 124 are used in the multi-column array 120, a second beamforming network 140 will be provided, connecting the fourth RF port 110-4 to the sixth RF port 110-6. Figure 1C The second polarized radiator 126-2 of the radiating element 124 shown.

[0064] The Blass matrix 140 includes eighteen directional couplers 150 arranged in a three-row, six-column configuration. The directional couplers are interconnected via multiple transmission lines. Figure 1C The line is shown in the diagram. Although the directional coupler 150 is... Figure 1CIn the schematic diagram, they are neatly arranged in rows and columns, but it should be understood that in some practical implementations, directional couplers can be arranged in staggered rows and / or columns, or even more randomly in their physical layout. However, as... Figure 1C As shown, the directional couplers 150 are functionally arranged in rows and columns, taking into account the way they are interconnected and connected to the phase shifter assembly 132 and the feed plate 128.

[0065] Delay elements 160 are provided along the transmission lines that interconnect adjacent directional couplers 150 in each row and along the transmission line that connects the rightmost directional coupler 150 to the terminating resistor 170 (described below), such that a total of eighteen delay elements 160 are provided. The delay elements 160 and transmission lines can be implemented together by forming the transmission lines requiring a larger delay into tortuous transmission line segments that increase the desired amount of phase delay. Each directional coupler 150 has an input port 152 (upper left port), a through port 154 (lower left port), an isolation port 156 (upper right port), and a coupling port 158 ​​(lower right port).

[0066] An output 134 from each of phase shifter assemblies 132-1 to 132-3 is connected to a corresponding input port among the input ports 142-1 to 142-3 of the Blass matrix 140. A first input port 142-1 is coupled to input port 152 of the first (leftmost) directional coupler 150 in the top row, a second input port 142-2 is coupled to input port 152 of the first (leftmost) directional coupler 150 in the middle row, and a third input port 142-3 is coupled to input port 152 of the first (leftmost) directional coupler 150 in the bottom row. A coupling port 158 ​​of each of the six directional couplers 150 in the top row is coupled to a corresponding feed plate among the six feed plates 128. An isolation port 156 of each of the six directional couplers 150 in the bottom row is coupled to a corresponding load (e.g., a corresponding 50-ohm resistor) among the six loads 170. The through port 154 of each directional coupler 150 in the last (rightmost) column is also coupled to the corresponding load 160 (e.g., the corresponding 50-ohm resistor) via a corresponding delay line in the delay line 160. As shown, the remaining ports of the directional couplers 150 are interconnected. Specifically, the through port 154 of each of the remaining directional couplers 150 is coupled to the input port 152 of the next directional coupler 150 in the same row via a corresponding delay line in the delay line 160. Similarly, the isolation port 156 of each directional coupler 150 in a row is coupled to the coupling port 158 ​​of the directional coupler 150 in the next row (except for the isolation port 156 of the directional coupler 150 in the last row, as discussed above).

[0067] The multi-beam sector split base station antenna 100 can generate M (M equals 3 here) antenna beams (each polarization) pointing in different directions.

[0068] While the embodiments of the invention discussed above are implemented using Blass matrix beamforming networks, it should be understood that the embodiments of the invention are not limited thereto. For example, in other embodiments, each Blass matrix can be replaced with a Nolen matrix. Exemplary embodiments of suitable Nolen matrix designs are disclosed in PCT Patent Publication No. WO 2024 / 118325, published on June 6, 2024, the entire contents of which are incorporated herein by reference. Various modifications of Blass and Nolen matrices are also known in the art, and any of these variations can be used to implement base station antennas according to embodiments of the invention, as with other known types of beamforming networks.

[0069] Figure 2A This is a side view of a conventional 3x6 Blass matrix beamforming network 200 implemented in a multilayer printed circuit board 210. In this document, the Blass matrix beamforming network 200 may also be referred to as a Blass matrix printed circuit board 200. The multilayer printed circuit board 210 includes a first dielectric substrate and second dielectric substrates 212-1, 212-2, and first metallization layers 214-1 to third metallization layers 214-3, which are stacked sequentially such that dielectric layers 212 and metallization layers 214 are stacked alternately. Specifically, the first (upper) metallization layer 214-1 is disposed on the upper surface of the first dielectric substrate 212-1, the third (lower) metallization layer 214-3 is disposed on the lower surface of the second dielectric substrate 212-2, and the second (intermediate) metallization layer 214-2 is disposed between the first dielectric substrate and the second dielectric substrates 212-1, 212-2.

[0070] Figure 2B It includes Figure 2A A tiled image of the planar (top view) view of each metallization layer of a printed circuit board. (Example) Figure 2B As shown, the first (upper) metallization layer 214-1 includes a first metal pattern 220, which includes a plurality of first metal pads 222 and a plurality of first metal traces 224. The third (lower) metallization layer 214-3 includes a third metal pattern 240, which includes a plurality of second metal pads 242 and a plurality of second metal traces 244. The second (middle) metallization layer 214-2 includes a second metal pattern 230, which has a plurality of openings 232 therein, with metal omitted from the openings.

[0071] Each first metal pad 222 is configured to be capacitively coupled to a corresponding metal pad in the second metal pad 242 through a corresponding opening in the opening 232, to form a corresponding Figure 1C The directional coupler 150 shown has multiple "slotted" directional couplers 250. Figure 2B The three dashed boxes on the upper left show the components forming one of the directional couplers 250. The amount of coupling between the first metal pad and the second metal pad 222, 242 of each directional coupler 250 can be controlled by adjusting the size of the first metal pad and the second metal pad 222, 242 and / or the size of the opening 232. The position of the first metal trace 224 connected to the left side of each first metal pad 222 corresponds to... Figure 1C The input port 152 of the directional coupler 150 shown. The first metal trace 224 is connected to the right side of each first metal pad 222 at a position corresponding to... Figure 1C The through port 154 of the directional coupler 150 shown. The second metal trace 244 connects to the left side of each second metal pad 242 at a position corresponding to... Figure 1C The isolation port 156 of the directional coupler 150 shown. The second metal trace 244 is connected to the right side of each second metal pad 242 at a position corresponding to... Figure 1C The coupling port 158 ​​of the directional coupler 150 shown.

[0072] First metal trace 224 implemented Figure 1C The delay element 160 is shown in the diagram. It can be seen that the amount of delay provided by each delay element 160 can be constant within a row directional coupler 150, and can be increased incrementally from one row to the adjacent row, such that the minimum delay element 160 providing the minimum delay is in the top row directional coupler 150, and the maximum delay element 160 achieving the maximum delay is in the bottom row directional coupler 150.

[0073] like Figure 2B As shown, each first metal trace 224 connects the through port 154 of the first directional coupler 250 to the input port 152 of the second directional coupler 250, which is in the same row as the first directional coupler 250 and to the right of the first directional coupler 250. Except for the last directional coupler 250 in each row, the first metal trace 224 implementing the delay element 160 connects the through port 154 of the directional coupler 250 to the corresponding terminating resistor 170 (the terminating resistor is in...). Figure 2A They are not shown because they are typically implemented as surface-mount resistors on a printed circuit board, but... Figure 1C (As shown in the circuit diagram). In the Blass matrix, the amount of delay provided by each delay element 160 varies based on the position of the delay element 160 within the Blass matrix. (As shown in the circuit diagram). Figure 2A As shown, the delay element 160 in the "lower" row is designed to provide a longer delay. To increase the amount of delay, the first metal trace 224 in the "lower" row of the Blass matrix is ​​implemented as a zigzag metal trace. The width-direction separation between adjacent row directional couplers 250 is configured to allow the first metal trace 224 to have sufficient zigzag amount to achieve the desired amount of delay.

[0074] Figure 2A The three first metal traces 222 on the left side are connected to Figure 1B The corresponding outputs 134 of the first phase shifter assembly 132-1 to the third phase shifter assembly 132-3. Figure 2A The three first metal traces 222 on the right side are connected to Figure 1B The corresponding terminating resistor 170 on the right side. Six open-ended second metal traces 244 (e.g., via coaxial cable) terminating in the middle of the third metallization layer 214-3 are connected to Figure 1C The corresponding feed boards in the six feed boards 228 shown. Six open-end second metal traces 244 terminating along the upper edge of the third metallization layer 214-3 are connected to the corresponding terminating resistors in the six terminating resistors 170 (resistors 170 in Figure 2A Not shown in the image, but... Figure 1C (As shown in the circuit diagram).

[0075] Figure 2C This is a rear view of a conventional multi-beam sector-split base station antenna 1, which includes twenty [unclear - possibly referring to specific antennas or components]. Figure 2A-2B A Blass matrix-based printed circuit board 200. (e.g.) Figure 2C As shown, the Blass matrix-based printed circuit board 200 is mounted at spaced-out locations along the length of the antenna 1, wherein... Figure 2B Ten Blass matrix-based printed circuit boards 200 are visible. (See again...) Figure 2B It can be seen that for 300cm 2 The surface area of ​​each main surface of the Blass matrix printed circuit board 200 is 30 cm long and 10 cm wide. Due to this large surface area, it is impossible to assemble all twenty Blass matrix printed circuit boards 200 along the length of antenna 1. Therefore, as Figure 2D As shown, Blass matrix printed circuit boards 200 are stacked in pairs within the base station antenna 1 to accommodate all twenty Blass matrix-based beamforming networks 200 within the antenna 1. Specifically, each Blass matrix printed circuit board 200 is mounted on a separate metal plate 10, which facilitates the dissipation of heat generated in the terminating resistor 170 during operation of the antenna 1.

[0076] As discussed above, according to some embodiments of the present invention, a method is provided that can be significantly smaller than... Figure 2A The Blass matrix 200 shown is a Blass matrix beamforming network. A conventional Blass matrix 200 holds directional couplers 250 in rows and columns. A first metal trace 224 bends in a region on a printed circuit board 210 between adjacent row directional couplers 250 to achieve the desired delay. This design results in a printed circuit board 210 with a relatively large width.

[0077] Figure 3A It is applicable to implementation according to embodiments of the present invention. Figure 1C A side view of the Blass matrix beamforming network 300 of the Blass matrix 140. The Blass matrix beamforming network 300 is implemented using a multilayer printed circuit board 310, and therefore may also be referred to herein as the Blass matrix printed circuit board 300. Figure 3B It provides Figure 3A A top view mosaic of each metallization layer of the Blass matrix printed circuit board 310.

[0078] like Figure 3A As shown, the multilayer printed circuit board 310 includes a first dielectric substrate and second dielectric substrates 312-1 and 312-2, and a first metallization layer 314-1 to a third metallization layer 314-3. The first to third metallization layers are stacked sequentially, such that the dielectric layer 312 and the metallization layer 314 are stacked alternately. The first (upper) metallization layer 314-1 is on the upper surface of the first dielectric substrate 312-1, the third (lower) metallization layer 314-3 is on the lower surface of the second dielectric substrate 312-2, and the second (intermediate) metallization layer 314-2 is between the first dielectric substrate and the second dielectric substrates 312-1 and 312-2.

[0079] refer to Figure 3B The first (upper) metallization layer 314-1 includes a metal pattern 320, which includes a plurality of first metal pads 322 and a plurality of first metal traces 324. The third (lower) metallization layer 314-3 includes a metal pattern 340, which includes a plurality of second metal pads 342 and a plurality of second metal traces 344. The second (intermediate) metallization layer 314-2 includes a metal pattern 330, which has a plurality of openings 332 therein, in which metal is omitted. Each first metal pad 322 is configured to capacitively couple with a corresponding second metal pad in the second metal pad 342 through a corresponding opening in the opening 332 to form a corresponding Figure 1C The directional coupler 150 in the middle has multiple directional couplers 350. Figure 3BThe three dashed boxes in the diagram illustrate the components forming one of the directional couplers 350. A first metal trace 324 connects to the left side of each first metal pad 322 to form an input port 352 of the directional coupler 350, while a first metal trace 324 connects to the right side of each first metal pad 322 to form a through port 354 of the directional coupler 350. A second metal trace 344 connects to the left side of each second metal pad 342 to form an isolation port 356 of the directional coupler 350, and a second metal trace 344 connects to the right side of each second metal pad 342 to form a coupling port 358 of the directional coupler 350. The first metal trace 324 is connected to... Figure 2B The first metal pad 322 is interconnected in the same manner as shown, and the second metal trace 344 is connected to... Figure 2B The second metal pad 342 is interconnected in the same manner as shown. The first metal trace 324 implements... Figure 1C The delay element 160 is shown. Therefore, the Blass matrix printed circuit board 300 has a delay element 160 as shown. Figure 2A-2B The Blass matrix printed circuit board has the same general design as the 200.

[0080] Each directional coupler 350 is a slot-type directional coupler because the slot 332 in the second metallization layer 314-2 is positioned between the first metal pad 322 and the second metal pad 342, allowing RF energy to be coupled between the corresponding second metal pads in each of the first metal pads 322 and the second metal pads 342 through the corresponding slots in the slot 332. The amount of coupling between the first metal pad 322 and the second metal pad 342 varies with the length of the slot 332, the width of the slot 332, the thickness and dielectric constant of the first dielectric substrate and the second dielectric substrates 312-1, 312-2, and the width of the first metal pad and the second metal pad 322, 342. In the depicted embodiment, each slot 332 has the same length (i.e., the same length dimension), and the thickness and dielectric constant of the first dielectric substrate and the second dielectric substrates 312-1, 312-2 are constant. Therefore, the coupling amount between the first metal pad and the second metal pad 322, 342 can be set by appropriately adjusting the width of the slot 332 and the width of the first metal pad 322 and the second metal pad 342. In the depicted embodiment, the first metal pad 322 and the second metal pad 342 have the same width for each directional coupler 350, but the width is different for different directional couplers 350. The width of the first metal pad and the second metal pad 322, 342, and the slot 332 can be selected to achieve the desired coupling amount while maintaining the desired impedance to minimize return loss.

[0081] However, the first metal trace 324 of printed circuit board 310 has a different design than the first metal trace 224 of printed circuit board 210. Furthermore, the layout of the first metal pad and the second metal pads 322, 342 is modified in printed circuit board 310 compared to printed circuit board 210. Specifically, as... Figure 3B As shown, compared to the corresponding distance between the first metal pads 222 and the distance between the second metal pads 224 in the lower two rows of directional couplers 250 in the Blass matrix printed circuit board 200, the distance between the first metal pads 322 and the distance between the second metal pads 324 in the lower two rows of directional couplers 350 in the Blass matrix printed circuit board 300 is increased. Therefore, the length of the printed circuit board 310 increases from 30 cm to 36 cm. Furthermore, since the first metal trace 324 in the first row has no bends to achieve the desired delay, the first metal pads 322 in the upper row are offset from the corresponding first metal pads 322 in the lower two rows. Due to the increased distance between the first metal pads 322 in the lower two rows of directional couplers 350, it is possible to form a first metal trace 324 with a wave shape including multiple peaks and valleys in the bottom row. This allows the first metal trace 324 in the bottom row to achieve the desired delay amount, while keeping the majority of each first metal trace 324 in the bottom row within the upper edge of the bottom row that is closest to the upper edge of the printed circuit board 310 (in Figure 3B In the view, the first horizontal axis H1 defined by the first metal pad 322 is connected to the lower edge of the bottom row that is closest to the lower edge of the printed circuit board 310. Figure 3B In the view, the first metal pad 322 defines the second horizontal axis H2. This can be referenced. Figure 3C Best viewed.

[0082] First refer to Figure 3C As can be seen, the rightmost first metal pad 322 has an upper edge closest to the upper edge of the printed circuit board 310 and a lower edge closest to the lower edge of the printed circuit board 310. Therefore, the upper and lower edges of the rightmost first metal pad 322 define the first horizontal axis and the second horizontal axes H1 and H2, respectively. Figure 3C As shown, more than 65% of the area of ​​each first metal trace 324 is located in the region defined between a corresponding pair of adjacent first metal pads 322 (i.e., the region defined by the edges of the two first metal pads 322 and the first and second horizontal axes H1, H2). In stark contrast, in Figure 2AIn this design, less than 25% of the area of ​​each first metal trace 224 in the bottom row is placed in the region defined between two adjacent first metal pads 222. In an exemplary embodiment, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, or at least 70% of the area of ​​each first metal trace 324 is placed in the region defined between two first metal pads 322 connected by the first metal trace 324. Due to this design, the distance between adjacent rows of first metal pads 322 can be significantly reduced, thereby allowing the width of the printed circuit board 310 to be reduced to 4 cm compared to the 10 cm width of the printed circuit board 210. Therefore, the surface area of ​​the printed circuit board 310 is less than half the surface area of ​​the printed circuit board 210.

[0083] Figure 3D This is a plan view of the first metallization layer 314-1' of the modified version 310' of the printed circuit board 310. (As shown by comparison...) Figure 3B and 3D It can be seen that the two first metallization layers 314-1 and 314-1' can be identical, except that the rightmost first metal pad 322 in the middle row directional coupler 350 of the first metallization layer 314-1 is moved to the open space to the right of the first row directional coupler 350 in the first metallization layer 314-1'. This allows the tortuous portion of the first metal trace 324 connecting the two rightmost first metal pads 322 in the lower two row directional couplers 350 to extend into the other row directional couplers 350. In other words, in the first metallization layer 314-1', the rightmost first metal pad 322 in the middle row is moved to the empty space in the upper right corner of the first metallization layer 314-1, which provides additional space for implementing the rightmost adjacent first metal trace 324 in the lower two row directional couplers 350. This additional space allows the rightmost first metal pad 322 in the lower two row directional couplers 350 to shift to the left, thereby allowing the length of the first metallization layer 314-1' to be reduced by about 5-8%. In printed circuit board 310', the slot 332 in the second metallization layer 314-2' and the second metal pad 342 in the third metallization layer 314-3', corresponding to the rightmost metal pad 322 in the two lower rows of directional couplers, are shifted so that they are aligned with the first metal pad 322. The end result is that the length of printed circuit board 310' can be approximately 5-8% smaller than the length of printed circuit board 310. This allows the length of printed circuit board 310 to be reduced to 33-34 cm or even smaller.

[0084] like Figure 3DAs shown, the first axis A1 intersects all the directional couplers 350 in the uppermost row of directional couplers 350. Additionally, the first axis A1 also intersects the rightmost directional coupler 350 in the middle row, because in this embodiment, this directional coupler 350 has been moved upwards into the empty space at the end of the first row of directional couplers 350.

[0085] Figure 3E It uses twenty Figures 3A-3B A rear view of the multi-beam sector-split base station antenna 400 implemented using the Blass matrix printed circuit board 300. It can be seen that, due to its reduced size, two Blass matrix printed circuit boards 300 can be mounted on each metal plate 410. Therefore, compared to base station antenna 1, base station antenna 400 requires fewer than ten metal plates 410, thereby reducing the material cost, weight, and manufacturing difficulty of base station antenna 400 compared to base station antenna 1. Furthermore, the smaller Blass matrix printed circuit board 310 also reduces the material cost of base station antenna 400 compared to base station antenna 1.

[0086] Combined again Figure 1A-1C refer to Figures 3A-3D As can be seen from some embodiments of the present invention, a multi-beam sector-split base station antenna 100 is provided, the multi-beam sector-split base station antenna comprising: an antenna array 120 including multiple columns 122 radiating elements 124; and a beamforming network 300 having at least two rows and two columns of directional couplers 350, wherein adjacent pairs of directional couplers 350 in each row are connected to each other by corresponding delay lines of multiple delay lines 324, 344, wherein at least some of the delay lines 324 have a waveform including multiple peaks and valleys. In some embodiments, at least one delay line of the delay lines 324 may have a waveform including at least three peaks or three valleys.

[0087] In some embodiments, the antenna array includes N columns 122 radiating elements 124, and a plurality of RF ports 110 are coupled to the antenna array 120 via a beamforming network 300. The beamforming network 300 may have M rows and N columns of directional couplers 350. In some embodiments, each row of the beamforming network 300 may have a different number of directional couplers 350 (e.g., Blass matrix embodiment). In other embodiments, each row of the beamforming network 300 may have the same number of directional couplers 350 (e.g., Nolen matrix embodiment).

[0088] The multi-beam antenna 100 may further include a reflector 102, and radiators 126 of the radiating elements 124 of the antenna array 120 may be mounted in front of the reflector 102, and a beamforming network 300 may also be mounted in front of the reflector 102. In some embodiments, the beamforming network 300 may be implemented in a printed circuit board 310, and the printed circuit board 310 may be mounted on the front surface of the reflector 102. In some embodiments, at least some of the radiating elements 124 fed by the beamforming network 300 may be mounted on the printed circuit board 310.

[0089] like Figure 3B As can be seen from the above, the first distance D1 between the first directional coupler and the last directional coupler in the first row (the uppermost row) can be less than the second distance D2 between the first directional coupler and the second-to-last directional coupler in the second row (the middle or bottom row).

[0090] like Figure 3D As shown, in some embodiments, the first axis A1 intersects with all directional couplers 350 in the first row and at least one directional coupler 350 that is part of the second row.

[0091] The smaller size of the Blass matrix printed circuit board 300 also allows for other design changes, which can further reduce the cost and / or improve the performance of multi-beam sector split base station antennas. For example, Figures 4A-4B A multi-beam sector split base station antenna 500 according to another embodiment of the present invention is shown, which splits each pair of Figures 3A-3B The miniaturized Blass matrix printed circuit board 300 is incorporated into a large power supply printed circuit board, so that each Blass matrix is ​​implemented in the same printed circuit board as the six power supply printed circuit boards it powers.

[0092] In particular, Figure 4A This is a plan view of a multipurpose printed circuit board 530, which includes a first Blass matrix, a second Blass matrix, and eight power supply boards implemented therein.

[0093] like Figure 4AAs shown, the printed circuit board 530 includes two low-frequency band feed plate regions 540-1 and 540-2, six mid-frequency band feed plate regions 550-1 and 550-2, and a pair of Blass matrix regions 560-1 and 560-2. Blass matrix region 560-1 implements a first Blass matrix 300-1, and Blass matrix region 560-1 implements a second Blass matrix 300-2. The printed circuit board 530 may include a pair of dielectric substrates and three metallization layers, the three metallization layers being configured to... Figures 3A-3B The Blass matrix printed circuit board 310 is arranged in the same manner as the corresponding layer. Each Blass matrix region 560 can achieve the same... Figures 3A-3B The Blass matrix 300 is the same as the Blass matrix. Each low-band feed plate region 540 may include a low-band radiating element 514 for the multi-beam sector split base station antenna 500 (see Figure 4B The installation location of the low-frequency radiating element 514. A pair of feed cables (not shown) for the low-frequency radiating element 514 can be terminated in each low-frequency radiating board area 540. Each mid-frequency radiating board area 550 can similarly include a mid-frequency radiating element 524 for the multi-beam sector split base station antenna 500 (see [link to documentation]). Figure 4B The installation location of ).

[0094] Figure 4B This is a schematic front view of a multi-beam sector-split base station antenna 500 (with the radome removed). Figure 4B As shown, the multi-beam sector-split base station antenna 500 includes a reflector 502. A first linear array and a second linear array 510-1, 510-2 of low-frequency band radiating elements 514 are mounted to extend forward from the reflector 502. A multi-column array 520 of mid-frequency band radiating elements 524 is also provided, wherein the mid-frequency band radiating elements 524 also extend forward from the reflector 502. The reflector 502 may include a flat metal surface that acts as a ground plane for the radiating elements 514, 524 and forward redirects the RF radiation emitted backward by the radiating elements 514, 524. The base station antenna 500 also includes ten Figure 4A A multi-purpose printed circuit board 530. Each multi-purpose printed circuit board 530 is mounted on the front side of the reflector 502. This is related to... Figure 2B In contrast to the base station antenna 1, the Blass matrix printed circuit board 200 is mounted behind the reflector 2.

[0095] like Figure 4B As shown, ten multi-purpose printed circuit boards 530 can be mounted on the front side of the reflector 502 because each Blass matrix region 560 has a significantly reduced width (4 cm, compared to...). Figure 2A-2BCompared to a conventional Blass matrix printed circuit board 200 (10cm). It is worth noting that mounting the multi-purpose printed circuit board 530 on the reflector 502 is advantageous because the reflector 502 is a large metal sheet that can very effectively dissipate the resistors surface-mounted in each Blass matrix region 560 (these resistors correspond to...). Figure 1C The heat generated in resistor 170 (in the circuit). Furthermore, since the multi-purpose printed circuit board 530 is directly mounted on the reflector 502 (although a thin dielectric layer such as a solder mask can be placed between each multi-purpose printed circuit board 530 and the reflector 502), the need for twenty metal plates 10 for antenna 1 or ten metal plates 410 for antenna 400 can be eliminated. This reduces cost, antenna weight, and assembly time.

[0096] The feed network of the array 520 of the intermediate frequency radiating elements 524 included in the base station antenna 500 can have Figure 1B The design shown is illustrated. Furthermore, each Blass matrix region 560 formed in the multipurpose printed circuit board 530 may have… Figure 1C The design shown can be used in... Figures 3A-3B (or Figure 3D Implement as shown in the diagram. Refer again. Figure 4A The first Blass matrix region 560-1 includes three inputs 342. Each of these inputs 142 can be... Figure 1B The connections are made as shown (e.g., via coaxial cables, not shown) to the outputs of the corresponding first polarization phase shifter assemblies 132-1 to 132-3. The six outputs 144 of the first Blass matrix region 560-1 are connected by corresponding first microstrip transmission lines 570 to the corresponding six intermediate frequency band feed plate regions 550-1 to 550-6. Similarly, the three inputs to the second Blass matrix region 560-2 are connected via... Figure 1BThe outputs of the corresponding second polarization phase shifter assemblies 132-4 to 132-6 are connected in the manner shown (e.g., via coaxial cable, not shown). The six outputs 144 of the second Blass matrix region 560-2 are also connected to the corresponding six intermediate frequency (IF) band feed plate regions 550-1 to 550-6 via corresponding second microstrip transmission lines 572. Each IF band feed plate region 560 includes a first power divider 562-1 connected to a corresponding microstrip transmission line in the first microstrip transmission line 570. The first power divider 562-1 has two outputs connected to the feed lines of the first polarization radiators 526-1 of the two IF band radiating elements 524 mounted in each IF band feed plate region 560. Each IF band feed plate region 560 also includes a second power divider 562-2 connected to a corresponding second microstrip transmission line in the second microstrip transmission line 572. The second power divider 562-2 has two outputs connected to the feed lines of the second polarized radiators 526-2 of the two mid-frequency radiating elements 524 installed in each mid-frequency feed plate region 560.

[0097] Conventionally, coaxial cables are used to connect each output of the Blass matrix printed circuit board (PCB) to a feed board PCB, which includes one or more radiating elements fed by the Blass matrix PCB. This design requires the antenna to include a large number of coaxial cables, each of which must be soldered to both the Blass matrix PCB and the feed board PCB. Therefore, a base station antenna comprising ten Blass matrix PCBs, each with six outputs, would require sixty coaxial cables to interconnect the ten Blass matrix PCBs to their associated feed board PCBs, necessitating 240 solder joints (i.e., solder joints for the center conductor and solder joints for the ground connector at each end of each coaxial cable). Forming these 240 solder joints is a labor-intensive operation, increasing cost and manufacturing time. Furthermore, solder joints are a potential source of PIM distortion. If such PIM distortion is discovered during factory testing, the faulty solder joints must be identified and redone.

[0098] Since the base station antenna 500 uses a multi-purpose printed circuit board 530, which implements both the Blass matrix and the feed board in a single printed circuit board, the first microstrip transmission line and the second microstrip transmission lines 570 and 572 replace the aforementioned coaxial cable, thereby reducing costs and manufacturing time and avoiding the aforementioned potential PIM distortion problem.

[0099] Still referencing Figures 4A-4BAs can be seen from another embodiment of the present invention, a multi-beam sector split base station antenna 500 is provided, which includes an antenna array 520 and a multi-purpose printed circuit board 530. The antenna array includes multiple rows of radiating elements 524. The multi-purpose printed circuit board includes: a plurality of feed plate regions 550; a first beamforming region 560-1, the first beamforming region including a first beamforming network 300, the first beamforming network including a plurality of directional couplers 350 and a plurality of outputs; and a plurality of transmission lines 570, the plurality of transmission lines connecting at least some of the outputs of the beamforming network 300 to corresponding feed plate regions in the feed plate regions 550, wherein each feed plate region 550 has one or more of the radiating elements 524 of the antenna array 520 mounted thereon.

[0100] In some embodiments, the multipurpose printed circuit board 530 may further include a second beamforming region 560-2, the second beamforming region including a second beamforming network 300, and at least some of the feed board regions 540 and 550 are located between the first beamforming region 560-1 and the second beamforming region 560-2. In some embodiments, transmission lines 570 and 572 may be microstrip transmission lines.

[0101] As described above, beamforming networks(s) 300 may include a Blass matrix. At least one output of the beamforming network 300 is connected via a coaxial cable to a feed board printed circuit board 528-1, wherein the feed board printed circuit board 528-1 is part of an outer column of the columns of radiating elements in the antenna array 520.

[0102] Figure 5A and 5B A multi-beam sector-split base station antenna 600 according to another embodiment of the present invention is shown. Specifically, Figure 5A This is a schematic partial view of a multi-beam sector-split base station antenna 600, and Figure 5B This is a perspective view of a small portion of antenna 600, showing how the Blass matrix printed circuit board 630 can be mounted behind reflector 602 of antenna 600. Figures 5A-5B The diagram shows only the reflector 602, two Blass matrix printed circuit boards 630, a feed board 628 for six mid-band radiating elements, twelve mid-band radiating elements 624, and multiple plastic supports 650 that hold the Blass matrix printed circuit boards 630 in place, with all other components of the antenna 600 omitted for simplification.

[0103] like Figures 5A-5BAs shown, each intermediate frequency (IF) feed board printed circuit board 628 is mounted in front of the reflector 602. A pair of IF radiating elements 624 are mounted to extend forward from each IF feed board printed circuit board 628. Each IF feed board printed circuit board 628 may be identical to the IF feed board region 550 of the multipurpose printed circuit board 530, except that the IF feed board printed circuit board 628 is implemented as a separate printed circuit board rather than as part of a larger printed circuit board. Therefore, further description of the IF feed board printed circuit board 628 will be omitted here. Figures 5A-5B As shown, multiple Blass matrix printed circuit boards 630 are mounted behind the reflector 602 of the antenna 600. Each Blass matrix printed circuit board 630 can be used Figures 3A-3B The Blass matrix printed circuit board 310 is implemented using a Blass matrix printed circuit board.

[0104] Each Blass matrix printed circuit board 630 is mounted generally perpendicular to the plane defined by the main surface of the reflector 602, wherein the length dimension of the Blass matrix printed circuit board 630 extends in the lateral direction of the antenna 600, and the width dimension of the Blass matrix printed circuit board 630 extends in the longitudinal direction of the antenna 600. The Blass matrix printed circuit boards 630 can be oriented in this manner because the width of each Blass matrix printed circuit board 630 is significantly reduced compared to a conventional Blass matrix printed circuit board, and therefore the Blass matrix printed circuit board 630 will not extend far in the depth direction of the antenna 600. The plastic support 650 may have clips or other features for mounting the support 650 within an opening 604 in the reflector 602. The plastic support 650 can hold each Blass matrix printed circuit board 630 in a proper position perpendicular to the reflector 602.

[0105] This design of antenna 600 avoids the need to stack the Blass matrix printed circuit board 630 as in conventional antennas, and reduces the cost, weight, and manufacturing time of antenna 600 compared to conventional multi-beam antennas. Furthermore, the output of the Blass matrix printed circuit board 630 can be directly connected to the intermediate frequency feed board printed circuit board 628 without the need for coaxial cable connections. This reduces the number of soldering operations by half (e.g., eliminating 120 solder joints) and eliminates the weight and cost of coaxial cables.

[0106] Still referencing Figures 5A-5B The multi-beam sector-split base station antenna 600 includes: a reflector 602; and an antenna array 620 (which in... Figures 5A-5B(shown only partially in the image), it includes multiple rows of radiating elements 624, wherein the radiating elements 624 extend forward from the reflector 602; and a beamforming network printed circuit board 630 mounted behind the reflector 602, the beamforming network printed circuit board 630 including tabs 632 that extend through openings 604 in the reflector 602 to be electrically connected to a subset of the radiating elements 624.

[0107] The multi-beam antenna 600 also includes a plurality of feed board printed circuit boards 628 mounted in front of the reflector 602, and each tab 632 in the beamforming network printed circuit board 632 can extend through a slot in the corresponding feed board printed circuit board in the feed board printed circuit board 628.

[0108] The beamforming network printed circuit board 630 can be mounted substantially perpendicular to the main surface of the reflector 602. The beamforming network included on the beamforming network printed circuit board 630 can, for example, use... Figures 3A-3C or Figure 3D The beamforming network 300 is used to achieve this.

[0109] Figure 6 According to another embodiment of the present invention, Figure 4A A schematic diagram of a modified version of the multipurpose printed circuit board 530, the multipurpose printed circuit board 700. (As shown by comparison...) Figure 4A and 6 It can be seen that the main difference between the multi-purpose printed circuit board 700 and the multi-purpose printed circuit board 530 is that the multi-purpose printed circuit board 700 does not include the two outer mid-frequency band feeder board areas 550-1 and 550-6. For example... Figure 4A One disadvantage of integrating the Blass matrix printed circuit board 300 into a multipurpose printed circuit board 530, which includes an intermediate frequency (IF) feed area 550, as in the embodiments described, is that the insertion loss of the microstrip transmission lines 570, 572 included in the multipurpose printed circuit board 530 is significantly higher than that of the coaxial cables they replace. This increase in insertion loss is manageable when the microstrip transmission lines 570, 572 connecting the beamforming network area 560 to the IF feed area 550 are short, as they will be small (e.g., less than 0.1 dB). However, as... Figure 4A As can be seen, the lengths of the microstrip transmission lines 570 and 572 that connect the output of the beamforming network region 560 to the outermost intermediate frequency (IF) band feed plate regions 550-1 and 550-6 are almost twice that of the microstrip transmission lines 570 and 572 that connect the output of the beamforming network region 560 to the four inner IF band feed plate regions 550-2 to 550-5. Therefore, the insertion loss along the microstrip transmission lines 570 and 572 that feed the IF band radiating elements 524 in the outer two columns of the IF band array 520 will be higher.

[0110] like Figure 6 As shown, to reduce insertion loss, only four intermediate frequency (IF) feed board regions 550-2 to 550-5 are implemented on the multi-purpose printed circuit board 700, and the outermost IF radiating elements 524 of the IF radiating elements 524 are mounted on separate IF feed board printed circuit boards 728-1, 728-2. Coaxial cables (not shown) are used to connect the outermost two outputs 760-1, 760-2 of each beamforming network region to these separate IF feed board printed circuit boards 728. This improves the insertion loss performance of the IF antenna array. Furthermore, compared to the multi-purpose printed circuit board 530, the overall size of the multi-purpose printed circuit board 700 can be reduced, and the wasted space on the multi-purpose printed circuit board 530 is eliminated, thereby reducing the overall cost.

[0111] While the above examples of the present invention primarily feature a three-beam sector-split base station antenna, it should be understood that embodiments of the present invention are not limited thereto. In other embodiments, the base station antenna may generate two antenna beams per polarization, or may generate more than three antenna beams (e.g., four, five, six, seven, eight, nine, or more per polarization). Generally, as the number of antenna beams increases, the number of columns of radiating elements tends to increase. For example, a multi-beam base station antenna configured to generate four antenna beams per polarization according to an embodiment of the present invention may have an eight-column antenna array. The number of rows in each beamforming network may be equal to the number of antenna beams generated by each antenna polarization. Thus, a four-beam (per polarization) multi-beam antenna according to an embodiment of the present invention may, for example, include a Blass matrix with four rows and eight columns of directional couplers. The number of antenna columns included in a multi-beam base station antenna according to an embodiment of the present invention may be set based on the desired sidelobe suppression and interference between adjacent antenna beams. The azimuth beamwidth of each antenna beam may be selected based on the spacing between adjacent columns of radiating elements and the azimuth beamwidth of each radiating element.

[0112] In the foregoing discussion, the terms "row" and "column" are used to refer to the beamforming network according to embodiments of the present invention. It should be understood that "row" and "column" are functionally defined based on the interconnection between directional couplers, and that, in practice, the directional couplers do not need to be physically aligned in the actual rows and columns.

[0113] It will be appreciated that this specification describes only a few exemplary embodiments of the invention, and that the techniques described herein have applicability beyond the exemplary embodiments described above.

[0114] Embodiments of the invention have been described above with reference to the accompanying drawings, in which embodiments of the invention are illustrated. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Throughout the text, the same reference numerals denote the same elements.

[0115] It will be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0116] It will be understood that when an element is described as being “on” another element, that element may be directly on the other element, or there may be intermediate elements present. Conversely, when an element is described as being “directly on” another element, there are no intermediate elements present. It will also be understood that when an element is described as being “connected” or “coupled” to another element, that element may be directly connected or coupled to the other element, or there may be intermediate elements present. Conversely, when an element is described as being “directly connected” or “directly coupled” to another element, there are no intermediate elements present. Other terms used to describe relationships between elements should be interpreted in a similar manner (i.e., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.).

[0117] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms “comprising,” “including,” and / or “having” as used herein mean the presence of the stated features, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, operations, elements, components, and / or groups thereof.

[0118] All aspects and elements of the embodiments disclosed above can be combined in any way and / or combined with aspects or elements of other embodiments to provide multiple additional embodiments.

Claims

1. A multi-beam antenna, comprising: Antenna array, the antenna array comprising multiple rows of radiating elements; as well as A beamforming network having at least two rows and two columns of directional couplers, wherein adjacent directional coupler pairs in each row are connected to each other by corresponding delay lines of a plurality of delay lines, wherein at least some of the delay lines have a wave shape including a plurality of peaks and valleys.

2. The multi-beam antenna of claim 1, wherein the antenna array comprises N columns of radiating elements and a plurality of radio frequency ("RF") ports coupled to the antenna array via the beamforming network.

3. The multi-beam antenna according to claim 1, wherein the beamforming network has M rows and N columns of directional couplers.

4. The multi-beam antenna according to claim 3, wherein each row has a different number of directional couplers.

5. The multi-beam antenna of claim 3, wherein each row has the same number of directional couplers.

6. The multi-beam antenna of claim 1 further includes a reflector, wherein the radiators of the radiating elements of the antenna array are mounted in front of the reflector, and the beamforming network is also mounted in front of the reflector.

7. The multi-beam antenna of claim 6, wherein the beamforming network is implemented in a printed circuit board, and the printed circuit board is mounted on the front surface of the reflector.

8. The multi-beam antenna of claim 1, wherein the beamforming network is implemented in a printed circuit board, and at least some of the radiating elements fed by the beamforming network are mounted on the printed circuit board.

9. The multi-beam antenna of claim 1, wherein at least one of the delay lines has a waveform comprising at least three peaks or three valleys.

10. The multi-beam antenna of claim 1, wherein the first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row.

11. The multi-beam antenna of claim 1, wherein the first distance between the first directional coupler and the last directional coupler in the first row is less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

12. The multi-beam antenna of claim 1, wherein the beamforming network is implemented in a beamforming network printed circuit board mounted behind a reflector of the base station antenna, and the beamforming network printed circuit board includes tabs extending through openings in the reflector to be electrically connected to a subset of the radiating elements.

13. The multi-beam antenna of claim 12, further comprising a plurality of feed board printed circuit boards mounted in front of the reflector, wherein each tab in the beamforming network printed circuit board extends through a slot in a corresponding feed board printed circuit board.

14. The multi-beam antenna of claim 12, wherein the beamforming network printed circuit board is mounted substantially perpendicular to the main surface of the reflector.

15. A multi-beam antenna, comprising: Antenna array, the antenna array comprising multiple rows of radiating elements; as well as A printed circuit board comprising: a plurality of feed plate regions; a first beamforming region including a first beamforming network including a plurality of directional couplers and a plurality of outputs; and a plurality of transmission lines connecting at least some of the outputs of the beamforming network to corresponding feed plate regions in the feed plate regions, wherein each feed plate region has one or more radiating elements of the antenna array mounted thereon.

16. The multi-beam antenna of claim 15, wherein the printed circuit board further comprises a second beamforming region, the second beamforming region comprising a second beamforming network, and at least some of the feed board regions are disposed between the first beamforming region and the second beamforming region.

17. The multi-beam antenna according to claim 15, wherein the transmission line is a microstrip transmission line.

18. The multi-beam antenna of claim 15, wherein the beamforming network comprises a Blass matrix or a Nolen matrix.

19. The multi-beam antenna of claim 15, wherein at least one output of the beamforming network is connected to the feed board printed circuit board via a coaxial cable.

20. The multi-beam antenna of claim 19, wherein at least one of the radiating elements that is part of an outer column of the column of radiating elements is mounted on the feed board printed circuit board.

21. The multi-beam antenna of claim 15, wherein the beamforming network has at least two rows and two columns of directional couplers, wherein adjacent directional coupler pairs in each row are connected to each other by corresponding delay lines of a plurality of delay lines, wherein at least some of the delay lines have a wave shape including a plurality of peaks and valleys.

22. The multi-beam antenna of claim 15, wherein the first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row.

23. The multi-beam antenna of claim 15, wherein the first distance between the first directional coupler and the last directional coupler in the first row is less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

24. The multi-beam antenna of claim 15 further includes a reflector, and the radiator of the radiating element of the antenna array is mounted in front of the reflector, wherein the beamforming network is also mounted in front of the reflector.

25. A multi-beam antenna, comprising: Reflector; An antenna array comprising multiple rows of radiating elements, wherein the radiating elements extend forward from the reflector; as well as A beamforming network printed circuit board, the beamforming network printed circuit board being mounted behind the reflector, the beamforming network printed circuit board including tabs extending through openings in the reflector to be electrically connected to a subset of the radiating elements.

26. The multi-beam antenna of claim 25, further comprising a plurality of feed board printed circuit boards mounted in front of the reflector, wherein each tab in the beamforming network printed circuit board extends through a slot in a corresponding feed board printed circuit board.

27. The multi-beam antenna of claim 25, wherein the beamforming network printed circuit board is mounted substantially perpendicular to the main surface of the reflector.

28. The multi-beam antenna of claim 25, wherein the beamforming network comprises at least two rows and two columns of directional couplers.

29. The multi-beam antenna of claim 28, wherein the first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row.

30. The multi-beam antenna of claim 28, wherein the first distance between the first directional coupler and the last directional coupler in the first row is less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

31. The multi-beam antenna of claim 28, wherein the beamforming network further comprises a plurality of delay lines, and adjacent directional couplers in each row are connected to each other by corresponding delay lines in the delay lines.

32. The multi-beam antenna of claim 31, wherein at least one of the delay lines has a waveform comprising multiple peaks or multiple valleys.

33. The multi-beam antenna of claim 25, wherein the beamforming network printed circuit board includes a matrix of directional couplers.

34. The multi-beam antenna of claim 33, wherein the matrix of the directional coupler includes a Blass matrix or a Nolen matrix.

35. A multi-beam antenna, comprising: Antenna array; as well as A beamforming network having multiple directional couplers interconnected by multiple transmission lines to define multiple rows and columns of directional couplers. The first axis intersects with all directional couplers in the first row and at least one directional coupler that is part of the second row.

36. The multi-beam antenna of claim 35, wherein there are at least three rows of directional couplers and at least four columns of directional couplers.

37. The multi-beam antenna of claim 35, wherein a second axis perpendicular to the first axis intersects with a first directional coupler in each row of directional couplers.

38. The multi-beam antenna of claim 35, wherein the first distance between the first directional coupler and the last directional coupler in the first row is less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

39. The multi-beam antenna of claim 35, wherein the beamforming network comprises a Blass matrix or a Nolen matrix.

40. A multi-beam antenna, comprising: Antenna array; as well as A beamforming network having multiple directional couplers interconnected by multiple transmission lines to define multiple rows and columns of directional couplers. The first distance between the first directional coupler and the last directional coupler in the first row is less than the second distance between the first directional coupler and the penultimate directional coupler in the second row.

41. The multi-beam antenna according to claim 40, wherein the transmission lines in the first row are straight transmission lines and the transmission lines in the last row are zigzag transmission lines.

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