CN216436120U

CN216436120U - Signal processing device and base station antenna

Info

Publication number: CN216436120U
Application number: CN202220013751.7U
Authority: CN
Inventors: 尹志伟; 万方文; 金定树
Original assignee: Commscope Technologies LLC
Current assignee: Commscope Technologies LLC
Priority date: 2022-01-05
Filing date: 2022-01-05
Publication date: 2022-05-03
Anticipated expiration: 2032-01-05

Abstract

The present disclosure relates to a signal processing apparatus and a base station antenna, the signal processing apparatus including: a substrate; a beam forming network disposed on one side of the substrate; the calibration circuit is arranged on the same side of the substrate, which is provided with the beam forming network; wherein the beam forming network is connected to the calibration circuit via connection traces on the substrate.

Description

Signal processing device and base station antenna

Technical Field

The present disclosure relates generally to the field of radio communication technology, and more particularly, to a signal processing apparatus and a base station antenna.

Background

Cellular communication systems are well known in the art. In a typical cellular communication system, a geographic area may be divided into a series of areas known as "cells," and each cell is served by a "macrocell" base station. For example, in the case of a liquid,each cell may have 1-50km²And an area of order, wherein the size of the cell depends on terrain, population density, and the like. A base station may include baseband equipment, radios, and base station antennas to provide two-way RF ("RF") communication with fixed and mobile subscribers ("users") located throughout a cell. Base station antennas are typically mounted on towers or other elevated structures, with the radiation beam generated by each antenna (the "antenna beam") directed outward to serve the entire cell or a portion thereof (the "sector"). Typically, a base station antenna comprises one or more phased arrays of radiating elements, wherein the radiating elements are arranged in one or more vertical columns when the antenna is installed for use. Here, "vertical" refers to a direction substantially perpendicular with respect to a plane defined by the horizon.

To increase capacity, cellular operators deploy so-called "small cell" base stations. Small cell base stations refer to low power base stations serving a much smaller area than typical macro cell base stations. Herein, the term "small cell" may cover base stations in small cells, microcells, picocells, and other base stations serving a small geographic area. For example, small cell base stations may be used to provide cellular coverage for high traffic areas within a macro cell, which allows the macro cell base station to offload most or all of the traffic near the small cell to the small cell base station.

Figure 1 is a schematic diagram of the structure of a conventional small cell base station 10. The base station 10 includes an antenna 20 that may be mounted on an elevated structure 30. In general, the antennas 20 of small cell base stations may be designed to provide omni-directional coverage in the azimuth plane, meaning that the antenna beams generated by the antennas 20 extend through a full 360 ° circle in the azimuth plane, and may have a suitable beam width in the elevation plane (e.g., 10 ° to 30 °). The antenna beam may optionally be slightly downtilted (which may be a physical downtilt or an electronic downtilt) in the elevation plane to reduce the antenna beam of the small cell base station antenna from spilling out into the area outside the small cell and also to reduce interference between the small cell base station and other base stations.

The small cell base station 10 may also include base station equipment such as one or more baseband units 40 and radios 42. The baseband unit 40 may receive data from another source, such as a backhaul network, and may process the data and provide a data stream to the radio 42. Radio 42 may generate RF signals including encoded data therein and may amplify and transmit the RF signals to antenna 20 for transmission, e.g., via cable connection 44. The radio 42 may form a plurality of RF signals based on the baseband data streams and pass each RF signal to a respective output terminal ("radio terminal") of the radio 42. In some cases, the antenna 20 may be a so-called "active antenna" in which the radio 42 is mounted directly on the antenna 20 or is implemented within the antenna 20. Active antennas are capable of electronically changing the shape and size of the generated antenna beam and are therefore also referred to as "beamforming antennas". It will also be understood that the small cell base station 10 in figure 1 may generally include various other equipment such as a power supply, a backup battery, a power bus, a controller, etc.

Some beamforming antennas include a beamforming network that processes RF signals fed to multiple columns of radiating elements of the beamforming antenna. For example, in some beamforming antennas, each radio terminal is coupled to a different column of radiating elements in a multi-column array of radiating elements through a beamforming network. The amplitude and phase of each RF signal may be set by the radio 42 and the beam forming network so that the columns of radiating elements work together to form a more focused, higher gain antenna beam with a narrower beamwidth in the azimuth plane. In a time division duplex ("TDD") transmission scheme, the antenna beam may be changed on a time slot by time slot basis such that the shape and pointing direction of the antenna may be electronically "steered" in the azimuth plane during each time slot to point at or near a served user (the pointing direction of the antenna beam refers to the direction in which the antenna beam has peak gain). In other cases, the antennas may be arranged such that there are multiple input ports of the sub-array in the elevation direction as well as in the azimuth direction, such that the antenna beam can be electronically steered and narrowed in both the azimuth and elevation planes. Beamforming antennas can exhibit higher antenna gain and support increased capacity due to their ability to narrow azimuth (or elevation) beamwidth and scan the antenna beam in the direction of a particular user.

The base station antenna may also include calibration circuitry that extracts a portion of the test signal that is transmitted into the array of radiating elements. By comparing the extracted part of the test signal with the reference signal, the weighting of the amplitude and phase of the signal to be transmitted can be varied to achieve calibration of the signal.

As the demand for miniaturization and integration of the small cell base station 10 increases, there is a need for improvements in the arrangement of various components in the small cell base station 10.

SUMMERY OF THE UTILITY MODEL

An object of the present disclosure is to provide a signal processing apparatus and a base station antenna.

According to a first aspect of the present disclosure, there is provided a signal processing apparatus comprising: a substrate; a beam forming network disposed on one side of the substrate; the calibration circuit is arranged on the same side of the substrate, on which the beam forming network is arranged; wherein the beamforming network is connected to the calibration circuitry via connection traces on the substrate.

According to a second aspect of the present disclosure, there is provided a base station antenna comprising: a reflector assembly including a plurality of reflector plates facing in different directions; a plurality of sets of arrays of radiating elements, each set of arrays of radiating elements in the plurality of sets of arrays of radiating elements being disposed on an outer side of a respective one of the plurality of reflector plates, respectively; and the signal processing device as described above, wherein the beam forming network of the signal processing device is connected to the plurality of sets of radiating element arrays, and the signal processing device is disposed in a space inside the plurality of reflector plates.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:

fig. 1 is a schematic structural diagram of a base station;

fig. 2 is a schematic structural diagram of a signal processing apparatus according to an exemplary embodiment of the present disclosure;

fig. 3 is a circuit schematic of a beam forming network and a radio in a base station antenna according to an example embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a base station antenna according to an exemplary embodiment of the present disclosure;

fig. 5 is a schematic horizontal cross-section of a base station antenna according to an exemplary embodiment of the present disclosure;

fig. 6 is a schematic horizontal cross-section of a base station antenna according to another exemplary embodiment of the present disclosure.

Note that in the embodiments described below, the same reference numerals are used in common between different drawings in some cases to denote the same portions or portions having the same functions, and a repetitive description thereof is omitted. In some cases, similar reference numbers and letters are used to denote similar items, and thus, once an item is defined in one figure, it need not be discussed further in subsequent figures.

For convenience of understanding, the positions, sizes, ranges, and the like of the respective structures shown in the drawings and the like do not sometimes indicate actual positions, sizes, ranges, and the like. Therefore, the present disclosure is not limited to the positions, dimensions, ranges, and the like disclosed in the drawings and the like.

Detailed Description

Various exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. That is, the structures and methods herein are shown by way of example to illustrate different embodiments of the structures and methods of the present disclosure. Those skilled in the art will appreciate that these examples are merely illustrative of embodiments of the disclosure and are not exhaustive. Furthermore, the drawings are not necessarily to scale, some features may be exaggerated to show details of some particular components.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely exemplary and not limiting. Thus, other examples of the exemplary embodiments may have different values.

With the introduction of fifth generation ("5G") cellular systems, beamforming antennas are now widely deployed. These antennas are mostly "flat panel" antennas that can provide coverage to a 120 ° sector of a base station. These antennas typically comprise either multiple linear arrays of radiating elements or one or more multi-column arrays of radiating elements, all of which are mounted on the reflector of the panel antenna. The linear array of radiating elements may be designed to generate a static antenna beam covering the entire 120 ° sector, while the multi-column array is designed to work with the radio and beamforming network to generate a more focused antenna beam with higher antenna gain, and may be electronically steered to cover different portions of the 120 ° sector. For example, 8T/8R radios and beamforming networks have been developed, which are typically used with four-column arrays of radiating elements. These 8T/8R radios may have a total of eight radio terminals, four of which are coupled via the beam forming network to-45 ° radiators of radiating elements in four columns of the array (one radio terminal per column), and the other four of which are coupled via the beam forming network to +45 ° radiators of radiating elements in four columns of the array (one radio terminal per column). A four column array may generate a pair of antenna beams simultaneously, i.e. one at each polarization. The 8T/8R radio sets the amplitude and phase of the RF signal output through each radio terminal so that the generated antenna beam has a reduced beam width in the azimuth plane and thus a higher antenna gain, and can also electronically steer the antenna beam in the azimuth plane to point in a desired direction. For example, an 8T/8R radio may change the pointing direction of the generated antenna beam on a slot-by-slot basis of a TDD communication scheme.

In addition, the beamforming base station antenna may also include calibration circuitry (which is typically implemented on a printed circuit board and referred to as a calibration circuit board) to extract a portion of the test signal transmitted into the radiating element. By comparing the extracted portion of the test signal with the reference signal, it may be helpful to determine the weighting of the amplitude and phase of the signal to be transmitted to achieve the desired beam pattern.

The calibration circuit board and the beam forming network are typically provided separately, for example the calibration circuit board may be provided close to the radiating elements and the beam forming network may be provided remote from the radiating elements. To enable signal transmission therebetween, the terminals of the calibration circuit board and the corresponding terminals of the beam forming network may be connected together by, for example, coaxial cables or the like. However, coaxial cables may occupy a large amount of space and increase the cost and weight of the antenna. In addition, coaxial cables may increase insertion loss, cause impedance matching problems, and require soldered connections that may be potential sources of passive intermodulation distortion ("PIM") signals, all of which may degrade the performance of the base station antenna.

In order to solve the above-described problems, the present disclosure provides a signal processing apparatus and a base station antenna including the same. The base station antenna may be a small cell beamforming base station antenna. The signal processing apparatus may include the beam forming network and the calibration circuit integrated on the same substrate, and thus, it is not necessary to connect the beam forming network to the calibration circuit using, for example, a coaxial cable or the like, which contributes to improving the integration of the base station antenna, making the base station antenna smaller, and in addition, may improve the performance of the base station antenna, and reduce the manufacturing cost.

As shown in fig. 2, the signal processing apparatus may include a substrate 110, a beam forming network 250, and a calibration circuit 120. Therein, the beam forming network 250 and the calibration circuit 120 may be provided on the same side of the substrate 110, and the beam forming network 250 may be connected to the calibration circuit 120 via connection traces 130 on the substrate 110. It will be appreciated that the beam forming network 250 and the calibration circuit 120 themselves may also be formed from corresponding traces on the substrate 110. In this way, the beam forming network 250 may no longer be connected to the calibration circuit 120 by a coaxial cable.

In some embodiments, at least a portion of the beamforming network 250, at least a portion of the calibration circuitry 120, and the connecting traces 130 may be integrally formed. In particular, at least a portion of the beam forming network 250, at least a portion of the calibration circuitry 120, and the connecting traces 130 may be formed in the same process step or set of process steps. For example, a patterned metal pattern may be integrally formed on the substrate 110 by one or more steps, which may include at least a portion of the beam forming network 250, at least a portion of the calibration circuitry 120, and the connection traces 130. However, it is understood that the beam forming network 250, calibration circuitry 120, and connection traces 130 may be formed in different process steps, if desired, but they will all be integrated on the substrate 110, thereby eliminating the need for additional connection components to make the connection between the beam forming network 250 and the calibration circuitry 120.

In some embodiments, at least a portion of the beamforming network 250, at least a portion of the calibration circuitry 120, and the connecting traces 130 may be formed of the same material. Alternatively, different materials may be included in the beam forming network 250, calibration circuit 120, and connecting traces 130, as desired.

Each connecting trace 130 may be considered part of a trace that is part of at least one of the beam forming network 250 and the calibration circuit 120, depending on the manner in which the pattern on the substrate 110 is partitioned. For example, each connecting trace 130 may be considered part of the beamforming network 250, or may be considered part of the calibration circuit 120, or a first portion of each connecting trace 130 may be considered part of the beamforming network 250 and a second portion of each connecting trace 130 may be considered part of the calibration circuit 120. In this case, it can also be considered that there is a direct connection between the beam forming network 250 and the calibration circuit 120, without any other connection components such as connection terminals, cables, etc. in between. However, it is understood that the connecting trace 130 may also be considered a separate component that is neither part of the beamforming network 250 nor part of the calibration circuit 120. This is only a difference in the division method, and has no influence on the structure of the actual signal processing apparatus.

Further, to improve the signal transmission performance of the signal transmission arrangement, the shape of each connection trace 130 may be configured to match the impedance at the connection of the beamforming network 250 and the calibration circuit 120. In other words, at the connection of the beamforming network 250 to the calibration circuit 120, the impedance of the calibration circuit 120 as seen by the beamforming network 250 and the impedance of the beamforming network 250 as seen by the calibration circuit 120 are equal to each other, thereby reducing or avoiding reflections of signals entering the input of the beamforming network 250 from the output of the calibration circuit 120.

In some embodiments, as shown in fig. 2, some or all of the connection traces 130 may include respective bends. The bend increases the length of each connection trace 130, which may improve impedance matching. In some embodiments, the bend may be formed by one or more "S" shaped traces or inverse "S" shaped traces connected to each other. It is understood that the bending portion may have other shapes as long as the length satisfies the requirement of impedance matching, and is not limited herein.

As shown in fig. 2, the beamforming network 250 may include a plurality of input ports 251, the calibration circuit 120 may include a plurality of output ports 122, and each input port 251 of the plurality of input ports 251 of the beamforming network 250 may be connected to a corresponding one of the plurality of output ports 122 of the calibration circuit 120 via a corresponding one of the connection traces 130. That is, the number of input ports 251 of the beam forming network 250, the number of output ports 122 of the calibration circuit 120, and the number of connection traces 130 may be equal to one another and may be connected in a one-to-one correspondence as shown in fig. 2.

Further, in order to avoid mutual interference between signals simultaneously traveling in the plurality of connection traces 130, the plurality of connection traces 130 on the substrate 110 may extend parallel to each other to keep a spacing distance between adjacent connection traces 130 substantially constant, and the spacing distance should be sufficient to avoid interference. Further, in order to fully utilize the layout space on the substrate 110 such that the separation distance between each pair of connected connection traces 130 is sufficient to avoid interference between signals, the plurality of connection traces 130 may be uniformly distributed on the substrate 110 in a direction perpendicular to the direction in which the connection traces 130 extend, rather than being concentrated in a small portion of the substrate 110.

The beamforming network 250 may comprise a passive beamforming network, which may comprise a butler matrix. In the particular embodiment shown in fig. 2, beam forming network 250 includes two butler matrices that can feed different arrays of radiating elements, respectively, or feed radiators of radiating elements with different polarizations in the same array of radiating elements. It is understood that more or less butler matrices may be included in the beamforming network 250, and/or circuitry other than butler matrices may be used, as desired.

Further, as shown in fig. 3, the butler matrix may include a first hybrid coupler 260-1, a second hybrid coupler 260-2, a third hybrid coupler 260-3, and a fourth hybrid coupler 260-4, and a first phase retarder 270-1 and a second phase retarder 270-2. The first input 262-1 of the first hybrid coupler 260-1 may serve as a first input of a butler matrix, the second input 262-2 of the first hybrid coupler 260-1 may serve as a second input of the butler matrix, the first output 264-1 of the first hybrid coupler 260-1 may be connected to the first input 262-1 of the third hybrid coupler 260-3 via a first phase retarder 270-1, and the second output 264-2 of the first hybrid coupler 260-1 may be connected to the first input 262-1 of the fourth hybrid coupler 260-4; the first input port 262-1 of the second hybrid coupler 260-2 may serve as a third input port of the butler matrix, the second input port 262-2 of the second hybrid coupler 260-2 may serve as a fourth input port of the butler matrix, the first output port 264-1 of the second hybrid coupler 260-2 may be connected to the second input port 262-2 of the third hybrid coupler 260-3, and the second output port 264-2 of the second hybrid coupler 260-2 may be connected to the second input port 262-2 of the fourth hybrid coupler 260-4 via a second phase retarder 270-2; the first output port 264-1 of the third hybrid coupler 260-3 may be the first output port of the butler matrix and the second output port 264-2 of the third hybrid coupler 260-3 may be the second output port of the butler matrix; and the first output port 264-1 of the fourth hybrid coupler 260-4 may be the third output port of the butler matrix and the second output port 264-2 of the fourth hybrid coupler 260-4 may be the fourth output port of the butler matrix. Wherein the first phase retarder 270-1 and the second phase retarder 270-2 may each be a 45 ° phase delay (lag) trace. Furthermore, a respective connection terminal can be connected to each output port of the butler matrix in order to transmit signals to a component outside the signal processing device. In the following, the working principle of the beam forming network will be explained in detail in connection with other components in the base station antenna.

As shown in fig. 2, the calibration circuit 120 may include a plurality of transmission paths 124, a plurality of coupling paths 125, and a power splitter 126. The plurality of transmission paths 124 may be respectively connected between a corresponding one of the plurality of input ports 121 and a corresponding one of the plurality of output ports 122 of the calibration circuit 120. Each coupling path 125 of the plurality of coupling paths 125 may be disposed at least partially adjacent to a respective one 124 of the plurality of transmission paths 124, respectively, such that a portion of the signal in the respective one 124 of the plurality of transmission paths 125 is coupled out of the transmission path 124 and travels in the coupling path 125. The input ports of the power divider 126 may be connected to the coupling paths 125, respectively, and the output port of the power divider 126 may serve as the calibration port 123 of the calibration circuit. Wherein, corresponding connection terminals can be connected to the

input ports

121 and 123 of the calibration circuit 120 to realize signal transmission with other components except the signal processing device. The length of each transmission path 124 of calibration circuit 120 may be equal, the length of each coupling path 125 may be equal, and the length of each distribution path connected between each input port and output port of power splitter 126 may be equal. Such an arrangement may ensure that the variations in the amplitude and phase of the signals introduced by each individual signal path in calibration circuit 120 are substantially equal, thereby avoiding inaccuracies in the calibration results caused by calibration circuit 120 itself introducing differences between the amplitude and phase of the multiple signals.

During calibration, a plurality of test signals may be generated by the radio and input accordingly at corresponding input ports 121 of the calibration circuit 120. A portion of each of these test signals may be coupled from transmission path 124 into coupling path 125 and output at calibration port 123 after combination by power splitter 126. By comparing the output signal output by the calibration port 123 with the reference signal, the amplitude and phase of the signal generated by the active transceiver can be adjusted to achieve the desired beam pattern.

In the signal processing device of the present disclosure, the beam forming network and the calibration circuit are integrated on the same substrate and are directly connected via the connection traces on the substrate, so that there is no need to use other components such as cables, connection terminals, and the like to realize the connection therebetween, contributing to the miniaturization and high integration requirements of the signal processing device and the base station antenna. In addition, the impedance matching between the beam forming network and the calibration circuit can be conveniently realized by adjusting the length of the connecting trace and the like, and the attenuation of signals in the transmission process can be well reduced, thereby being beneficial to improving the transmission performance of the base station antenna. Further, since the beam forming network, the calibration circuit and the connection traces may be at least partially formed integrally, and no additional connection components are required, the costs of the signal processing device and the base station antenna can be reduced.

The present disclosure also proposes a base station antenna which may comprise a reflector assembly, an array of sets of radiating elements and a signal processing arrangement as described above. The reflector assembly may comprise a plurality of reflector plates facing in different directions (which may be separate plates or a single structure bent to form plates facing in different directions). Each set of radiating element arrays may be disposed on an outer side of a corresponding one of the reflector plates, respectively, and the signal processing device may be disposed within a space defined on an inner side of the plurality of reflector plates, and the beam forming network of the signal processing device may be connected to the plurality of sets of radiating element arrays to provide the corresponding RF signals to the radiating elements.

The base station antenna of the present disclosure may generate a directional radiation pattern during any given time slot using substantially all of the transmit power of the radio while providing full 360 ° coverage in the azimuth plane. Small cell base station antennas according to embodiments of the present disclosure may support higher Effective Isotropic Radiated Power (EIRP) levels than conventional small cell beamforming systems and, in example embodiments, may operate in a frequency band of about 3.3GHz to 4.2GHz, or a portion thereof.

In some embodiments, a beamforming antenna according to embodiments of the present disclosure may include four linear arrays of radiating elements mounted on four major faces of a tubular reflector assembly having a substantially rectangular horizontal cross-section. The azimuthal boresight pointing direction of each linear array may be offset by about 90 °, about 180 °, and about 270 °, respectively, from the azimuthal boresight pointing directions of the remaining three linear arrays. The radiating elements in each linear array may comprise dual polarized radiating elements such as, for example, tilted-45 °/+45 ° crossed dipole radiating elements. The radiating elements may have a directional pattern in the azimuth plane, for example an azimuth half-power beamwidth between 50 ° and 100 °. Each of the four linear arrays may be connected to two RF terminals (one for each polarization) of the antenna, and the eight RF terminals may be connected to corresponding radio terminals on an eight-terminal 5G 8T/8R radio via a beamforming network. Each linear array may form a pair of directional antenna beams (one directional antenna beam per polarization). For example, each antenna beam may provide approximately 90 ° of coverage in the azimuth plane.

In some embodiments, the small cell base station antenna may use a passive beamforming network such as a 4x4 butler matrix to combine RF signals output through four radio terminals associated with one polarization, and then output the combined signal through one of the four outlets of the beamforming network to form a "sector" antenna beam, for example, providing 90 ° sector coverage in the azimuth plane. The radio apparatus can set the amplitude and phase weight of the RF signal output from each radio terminal in one of four ways. Each of the four different weight settings directs all of the RF energy output at the four radio terminals of the radio device to a selected one of the four linear arrays. In other words, the 5G radio and the passive beam forming network may be configured to work together to feed the signals output by all four radio terminals to a selected one of the linear arrays. This may be done for each of the two polarizations so that all of the RF energy output by the 5G radio during any given time slot may be radiated by a selected one of the four linear arrays. The radio is optionally programmed to output RF energy to two of the linear arrays during time slots serving users located at overlapping edges of coverage areas of two adjacent linear arrays.

Furthermore, by adjusting the weight settings, antenna beams having other shapes and/or pointing directions may be formed. For example, the technique may be used to change the boresight pointing direction of a sector antenna beam so that the peak gain of the sector antenna beam may point to any angle in the azimuth plane. Beamforming antennas according to embodiments of the present disclosure may also be configured to form antenna beams having other shapes by merely changing the weight settings. For example, the antennas may be configured to form antenna beams with omnidirectional, cardioid, and/or bidirectional radiation patterns in the azimuth plane simply by applying appropriate weight settings in the radio device. Thus, a single beamforming antenna, in combination with an off-the-shelf 5G radio, may form any standard antenna pattern that is typically desired by cellular operators.

A beam forming network based on a butler matrix is typically used to couple a plurality of radio terminals onto a planar multi-array of radiating elements. For example, a butler matrix may be used to allow two identically polarized radio terminals to share a multi-column array of radiating elements, such that each radio terminal is coupled to all radiating elements in the array. The butler matrix is typically configured to couple two radio terminals to the multi-column array in such a way that RF signals from a first radio terminal generate a first antenna beam pointing in a first direction in the azimuth plane, and RF signals from a second radio terminal generate a second antenna beam pointing in a different second direction in the azimuth plane. Such antennas are typically used in sector division applications, where a first antenna beam covers a first portion of a sector of a base station (e.g., the left side of a 120 sector) and a second antenna beam covers a second portion of the sector (e.g., the right side of the 120 sector). Embodiments of the present disclosure use a butler matrix type beam forming network in a completely different way, the butler matrix can act as a power combiner and switch, allowing all of the output power of the radio device to be transferred to a selected linear array of the plurality of linear arrays. The butler matrix may have superior power handling capability and good passive intermodulation distortion performance.

Figure 4 is a perspective view of a beamforming base station antenna 200 suitable for use as a small cell base station antenna (with its radome and top end cap removed) according to an embodiment of the present disclosure. As shown in figure 4, small cell base station antenna 200 comprises a rectangular tubular reflector assembly 210 having four facets 212-1 to 212-4. Four linear arrays 220-1 to 220-4 of dual polarized radiating elements 222 are mounted to extend outwardly from respective faces 212 of reflector assembly 210 (a fourth linear array 220-4 is not visible in fig. 4 but is identical to the other linear arrays 220 except for pointing in a different direction). In addition, the signal processing device may be installed in an inner space enclosed by the four faces 212-1 to 212-4 of the reflector assembly 210. The rectangular tubular reflector assembly 210 may comprise a single structure or may comprise multiple structures attached together. Each face 212 thereof may serve as a reflector and ground plane for the dual-polarized radiating elements 222 of the linear array 220 mounted thereon.

A plurality of RF terminals 244 may be mounted in the bottom end cap 240 of the base station antenna 200 and electrically connected to respective ones of a plurality of output ports 252 of a beam forming network 250 of the signal processing device. A total of eight RF terminals 244-1 through 244-8 may be provided, with two RF terminals 244 coupled to each linear array 220. A first RF terminal 244 coupled to each linear array 220 may support communication at a first polarization and a second RF terminal 244 coupled to each linear array 220 may support communication at a second polarization.

When the base station antenna 200 is installed for use, each linear array 220 may be substantially vertical with respect to the horizontal direction such that each linear array 220 includes a column of radiating elements 222. In the depicted embodiment, each linear array 220 includes a total of five radiating elements 222. It will be understood that other numbers of radiating elements 222 may be included in the linear array 220. In the depicted embodiment, each linear array 220 is implemented as three sub-arrays of radiating elements 222, with the top and bottom sub-arrays comprising two radiating elements 222 mounted on the same feed plate 228, and the middle sub-array comprising a single radiating element 222 mounted on its own feed plate 228. It will be understood that any suitable number of radiating elements 222 may be included in each sub-array, and that feed plate 228 may or may not be used. It will also be appreciated that different types of radiating elements 222 may be used. The base station antenna 200 may also include a radome and top end cap (not shown) that covers and protects the radiating elements 222 and other components of the base station antenna 200.

As mentioned above, some of the sub-arrays include a pair of radiating elements 222 mounted on a feed plate 228. Feed plate 228 may be configured to divide (the division need not be equal) the RF signal provided thereto into two sub-components and feed each sub-component to a respective one of radiating elements 222. Feed board 228 may include two inputs, one for each polarization. A director (not shown) may be installed in front of the dipole radiator 226 of each radiating element to narrow the beamwidth of the radiating element 222.

As discussed above, small cell base station antennas according to embodiments of the present disclosure may use a beamforming network, such as a butler matrix, to combine RF signals output by a radio and route the combined RF signals to selected ones of the linear arrays of antennas. In this way, the full transmit power of the radio may be utilized and the RF signal may be directed to a selected one of the linear arrays, which may be done on a slot-by-slot basis.

Fig. 3 is a simplified circuit diagram of a beamforming network 250 that may be used to pass RF signals between the four first polarized RF terminals 244 of the base station antenna 200 and the first polarized dipole radiators 226 of the four radiating elements 222 of the linear array 220, according to an embodiment of the present disclosure. Fig. 3 also illustrates the connection between the RF terminal 244 and corresponding radio terminals 44-1 to 44-8 on the radio device 42, which are each electrically connected to a respective input port 121 of the plurality of input ports 121 of the calibration circuit 120 of the signal processing apparatus. The radio 42 may be an 8T/8R 5G radio. Fig. 3 illustrates only radio terminal 44, RF terminal 244 and beam forming network 250 for one of the two polarizations supported by base station antenna 200 (e.g., -45 ° polarization). It will be appreciated that the elements shown in figure 3 will be repeated in the second polarisation.

As shown in fig. 3, the beam forming network 250 may include four hybrid couplers 260-1 through 260-4 and a pair of 45 phase retarders 270. Each hybrid coupler 260 may comprise, for example, a four port 90 ° hybrid coupler having first and second input ports 262-1 and 262-2 and first and second output ports 264-1 and 264-2. The four-port 90 hybrid coupler receives signals "A" and "B" at two input ports 262-1 and 262-2 and outputs a signal having an amplitude of "A/2 + B/2" at each output port 264-1, 264-2, with a 90 phase difference between the two output signals. 45 phase retarder 270 may include, for example, a delay trace or a more complex phase delay structure that may provide improved performance (i.e., uniform phase delay) over a wider frequency range. It will be appreciated that one or more of the 90 hybrid couplers may be replaced with a 180 coupler in combination with a delay trace.

As shown in fig. 3, input ports 262-1, 262-2 of the first hybrid coupler 260-1 are coupled to the first terminal 44-1 and the second terminal 44-2 of the 5G radio 42, while input ports 262-1, 262-2 of the second hybrid coupler 260-2 are coupled to the third terminal 44-3 and the fourth terminal 44-4 of the 5G radio 42. A first output port 264-1 of the first hybrid coupler 260-1 is coupled to an input port of a first 45 phase retarder 270-1 and a second output port 264-2 of the first hybrid coupler 260-1 is coupled to a first input port 262-1 of a fourth hybrid coupler 260-4. The output port of the first 45 phase retarder 270-1 is coupled to the first input port 262-1 of the third hybrid coupler 260-3. A first output port 264-1 of the second hybrid coupler 260-2 is coupled to a second input port 262-2 of the third hybrid coupler 260-3 and a second output port 264-2 of the second hybrid coupler 260-2 is coupled to an input port of a second 45 phase retarder 270-2. The output port of the second 45 phase retarder 270-2 is coupled to the second input port 262-2 of the fourth hybrid coupler 260-4.

The RF signal output from the first output port 264-1 of the third hybrid coupler 260-3 is coupled to the-45 dipole radiator 226 of the radiating element 222 of the first linear array 220-1. The RF signal output from the second output port 264-2 of the third hybrid coupler 260-3 is coupled to the-45 dipole radiator 226 of the radiating element 222 of the third linear array 220-3. The RF signal output from the first output port 264-1 of the fourth hybrid coupler 260-4 is coupled to the-45 dipole radiator 226 of the radiating element 222 of the second linear array 220-2. The RF signal output from the second output port 264-2 of the fourth hybrid coupler 260-4 is coupled to the-45 dipole radiator 226 of the radiating element 222 of the fourth linear array 220-4.

Assuming, as a result of the above connection, that the signal "a" is output from the radio terminal 44-1, the signal "B" is output from the radio terminal 44-2, the signal "C" is output from the radio terminal 44-3, and the signal "D" is output from the radio terminal 44-4, the phases of the sub-components of the signal a-D received at the linear arrays 220-1 to 220-4 are as follows:

linear array 220-1: a +45 °; b +135 °; c +90 °; d +180 °

Linear array 220-2: a +90 °; b +0 °; c +225 °; d +135 °

Linear array 220-3: a +135 °; b +225 °; c +0 °; d +90 °

Linear array 220-4: a +180 °; b +90 °; c +135 °; d +45 °

Table 1 below shows the amplitude and phase of the RF signals input into the beamforming network 250 (i.e., the amplitude and phase settings applied in the radio 42), which will result in all of the RF energy being directed to a single linear array 220.

TABLE 1

For example, focusing on row 1 of Table 1, it can be seen that when radio terminals 44-1 through 44-4 are respectively fed with signals having amplitudes/phases of 0.5/-45 °, 0.5/-135 °, 0.5/-90 °, 0.5/-180 °, then the RF power at each linear array 220 is as follows:

array 220-1

Array 220-2 ═ 0.5/45 ° +0.5/-135 ° +0.5/135 ° +0.5/-45 ° -0

Array 220-3 ═ 0.5/90 ° +0.5/90 ° +0.5/-90 ° +0

Array 220-4 ═ 0.5/135 ° +0.5/-45 ° +0.5/45 ° +0.5/-135 ° -0

In other words, small cell base station antenna 200 may be configured to output all RF energy to linear array 220-1 by programming 8T/8R radio 42 to apply appropriate amplitudes and phases to the RF signals output on the four terminals of the first polarization. A similar technique may be used to direct all RF energy to the second linear array 220-2, the third linear array 220-3, or the fourth linear array 220-4 by simply using the opposite combination in phase of the signals output at each radio terminal 44.

Thus, table 1 shows that by programming the radio 42 to apply appropriate amplitude and phase weights to the RF signals provided to the radio terminals 44-1 to 44-4, all of the RF energy transmitted through these radio terminals 44 is directed to a selected one of the four linear arrays 220.

It will be appreciated that fig. 3 illustrates one specific design of the butler matrix. Various different butler matrix designs may be used and the radio 42 may adjust the amplitude and phase of each input signal appropriately to route the RF energy to the selected linear array 220. It will also be appreciated that beamforming networks other than butler matrices may be used in some embodiments.

The base station antenna 200 may be relatively small, for example, it may be about 8 inches in diameter and about 2 feet in height. Such an antenna can be easily installed on most utility poles and street lamps.

Figure 5 is a schematic top view diagram of a small cell beamforming antenna 300 according to a further embodiment of the present disclosure. As shown in fig. 5, the base station antenna 300 may include a reflector assembly 310 having four faces 312-1 to 312-4 that collectively define a half-octagonal tube and an optional back wall. The signal processing device 100 may be disposed in a side of the reflector assembly opposite the radiating element. Two column arrays 320 of dual polarized radiating elements 222 are mounted in a side-by-side manner and extend outwardly from each face 312 of reflector assembly 310. Each two-column array 320 may include two linear arrays 220, each linear array 220 including six radiating elements 222, respectively. Fig. 5 is a schematic top view of a base station antenna 300, where only the radiating elements 222 at the top of each linear array 220 are visible. Each face 312 of reflector assembly 310 may serve as a reflector and as a ground plane for dual-polarized radiating elements 222 mounted thereon. The base station antenna 300 may be adapted to provide coverage to a 180 ° area in the azimuth plane. For example, the base station antenna 300 may be mounted on an exterior wall of a building. In other embodiments, the tubular reflector assembly 310 having the half-octagonal horizontal cross-section of fig. 5 may be replaced with a tubular reflector assembly having a full-octagonal horizontal cross-section, and eight additional linear arrays 220 may be provided. Such a base station antenna may operate with two 8T/8R radios or a single 16T/16R radio.

While base station antenna 200 supports a full 360 ° coverage area in the azimuth plane and base station antenna 300 supports a full 180 ° coverage area in the azimuth plane, it will be understood that embodiments of the present disclosure are not so limited. But may provide a small cell base station antenna designed to cover any adjacent portion or multiple non-adjacent portions in the azimuth plane.

Referring to figure 6, as another example, a small cell base station antenna 500 having a quadrilateral tubular reflector assembly 210 may be provided, but with an array 320 of radiating elements 222 mounted on only two opposing faces 212-1, 212-3 of the tubular reflector assembly 210, and the signal processing apparatus 100 may be disposed in an interior space enclosed by the four faces. Each array 320 can be a multi-column array, for example, two columns (or three columns) of radiating elements 222. The base station antenna 500 may be particularly suitable for use on tunnels, bridges and/or long straight highways. The base station antenna 500 may also operate with a 4T/4R TDD 5G radio, since the array is provided on only two of the four faces 212 of the reflector assembly 210.

It will also be understood that small cell base stations according to embodiments of the present disclosure may be configured to output RF energy to more than one linear array 220 in order to generate antenna beams having other shapes. When all the RF energy output by the four radio terminals 44-1 to 44-4 of the radio 42 is transferred to a single linear array 220, the antenna beam may be a so-called "sector" antenna beam designed to cover, for example, a 90 ° sector in the azimuth plane.

Further, by adjusting the weight settings applied to the 8T/8R radio 42, the pointing direction of the sector antenna beam can be adjusted. For example, all of the RF energy output on the four radio terminals 44-1 to 44-4 of the radio 42 may be directed to two adjacent ones of the linear arrays 220 of the base station antenna 200, rather than a single linear array 220. The technique may be used to change the boresight pointing direction of the sector antenna beam so that the peak gain of the sector antenna beam can point to any angle in the azimuth plane.

Furthermore, in some cases, a cellular operator may wish to generate antenna beams having shapes other than a "sector" shape. For example, a cellular operator may wish to generate antenna beams with omni-directional coverage in the azimuth plane in order to transmit control signals to all users within the coverage area of the base station antenna. By amplitude and phase weighting the RF signals output by radio terminals 44-1 to 44-4 in the manner shown in table 2, antenna beams with substantially omnidirectional coverage in the azimuth plane may be generated.

TABLE 2

Radio terminal 44-1	Radio terminal 44-2	Radio terminal 44-3	Radio terminal 44-4
				0.5/-45°	0.5/-135°	0.5/-135°	0.5/-45°

Cellular operators are also sometimes interested in deploying base station antennas that generate so-called "cardioid" antenna beams to provide coverage over approximately 180 ° in the azimuthal plane. For example, the base station antenna according to the embodiment of the present disclosure can also easily form such a cardioid antenna beam by amplitude and phase weighting the RF signals output from the radio terminals 44-1 to 44-4 in the manner as shown in table 3.

TABLE 3

Radio terminal 44-1	Radio terminal 44-2	Radio terminal 44-3	Radio terminal 44-4
				0.5/-45°	0.5/-45°	0.5/-45°	0.5/-45°

Furthermore, by directing the RF energy to three of the linear arrays 220 of appropriate amplitude and phase weights applied by the radio 42, the pointing direction of the cardioid antenna beam can also be adjusted to point in any direction in the azimuth plane.

Cellular operators are also sometimes interested in deploying base station antennas that generate so-called "bi-directional" antenna beams that provide coverage in two opposite directions in the azimuth plane. An antenna beam having a bidirectional shape in the azimuth plane may be useful in providing coverage in, for example, long straight highways and/or bridges, tunnels, etc. For example, the base station antenna according to the embodiment of the present disclosure can also easily form such "bidirectional" antenna beams by amplitude and phase weighting the RF signals output from the radio terminals 44-1 to 44-4 in the manner as shown in table 4.

TABLE 4

Radio terminal 44-1	Radio terminal 44-2	Radio terminal 44-3	Radio terminal 44-4
				0.5/-113°	0.5/-207°	0.5/-254°	0.5/-335°

It will be appreciated that many modifications may be made to the above described antenna without departing from the scope of the present disclosure. For example, the base station antenna 200 may include fewer or more than four linear arrays 220.

As indicated above, small cell beamforming base station antennas according to embodiments of the present disclosure may generate various standard antenna beams (omni-, sector-, cardioid-, bi-directional), while doing so may use the full transmit power of the cellular radio. In addition, by integrating the beam forming network and the calibration circuit on the same substrate and connecting the beam forming network and the calibration circuit by the connecting trace on the substrate, the requirements of miniaturization and low cost of the base station antenna can be met, and the situations of attenuation and impedance mismatching occurring in the base station antenna can be conveniently reduced so as to improve the performance of the base station antenna and save the cost.

In addition, embodiments of the present disclosure may also include the following examples:

1. a signal processing apparatus, the signal processing apparatus comprising:

a substrate;

a beam forming network disposed on one side of the substrate; and

a calibration circuit disposed on the same side of the substrate on which the beamforming network is disposed;

wherein the beamforming network is connected to the calibration circuitry via connection traces on the substrate.

2. The signal processing apparatus of 1, at least a portion of the beamforming network, at least a portion of the calibration circuitry, and the connecting trace are integrally formed.

3. The signal processing apparatus of 1, the connecting trace being part of a trace forming at least one of the beamforming network and the calibration circuit.

4. The signal processing apparatus of 1, the shape of the connection trace configured to cause impedance matching at a connection of the beamforming network and the calibration circuit.

5. The signal processing apparatus of claim 4, the connection trace comprising a bend.

6. The signal processing apparatus of claim 5, the length of the bend configured to impedance match at a connection of the beamforming network and the calibration circuit.

7. The signal processing apparatus of claim 1, the beamforming network comprising a plurality of input ports, the calibration circuit comprising a plurality of output ports, each of the plurality of input ports of the beamforming network connected to a respective one of the plurality of output ports of the calibration circuit via a respective one of the connecting traces.

8. The signal processing apparatus according to claim 7, a plurality of connection traces extend parallel to each other on the substrate.

9. The signal processing apparatus according to claim 7, wherein the plurality of connection traces are uniformly distributed on the substrate in a direction perpendicular to the direction in which the connection traces extend.

10. The signal processing apparatus of claim 1, wherein the beamforming network is a passive beamforming network.

11. The signal processing apparatus of 10, the passive beamforming network comprising a butler matrix.

12. The signal processing apparatus of claim 11, the butler matrix comprising first, second, third and fourth hybrid couplers and first and second phase retarders, wherein:

the first input port of the first hybrid coupler is used as the first input port of the Butler matrix, the second input port of the first hybrid coupler is used as the second input port of the Butler matrix, the first output port of the first hybrid coupler is connected to the first input port of the third hybrid coupler through the first phase retarder, and the second output port of the first hybrid coupler is connected to the first input port of the fourth hybrid coupler;

the first input port of the second hybrid coupler is used as a third input port of the butler matrix, the second input port of the second hybrid coupler is used as a fourth input port of the butler matrix, the first output port of the second hybrid coupler is connected to the second input port of the third hybrid coupler, and the second output port of the second hybrid coupler is connected to the second input port of the fourth hybrid coupler through the second phase retarder;

the first output port of the third hybrid coupler is used as the first output port of the Butler matrix, and the second output port of the third hybrid coupler is used as the second output port of the Butler matrix; and

the first output port of the fourth hybrid coupler serves as the third output port of the butler matrix, and the second output port of the fourth hybrid coupler serves as the fourth output port of the butler matrix.

13. The signal processing apparatus of claim 12, the first phase retarder and the second phase retarder each being a 45 ° phase delay trace.

14. The signal processing apparatus of 1, the calibration circuit comprising:

a plurality of transmission paths respectively connected between a corresponding one of the plurality of input ports and a corresponding one of the plurality of output ports of the calibration circuit;

a plurality of coupling paths, each of the plurality of coupling paths being respectively disposed at least partially adjacent to a corresponding one of the plurality of transmission paths such that a portion of a signal in the corresponding one of the plurality of transmission paths is coupled out of and travels in the transmission path; and

and the input ports of the power divider are respectively connected with the coupling paths, and the output port of the power divider is used as a calibration port of the calibration circuit.

15. The signal processing apparatus of claim 14, wherein each transmission path of the calibration circuit has an equal length.

16. The signal processing apparatus of claim 14, wherein each coupling path of the calibration circuit has an equal length.

17. The signal processing apparatus according to claim 14, wherein each of the distribution paths connected between each of the input ports and the output ports of the power divider has an equal length.

18. A base station antenna, the base station antenna comprising:

a reflector assembly including a plurality of reflector plates facing in different directions;

a plurality of sets of arrays of radiating elements, each set of arrays of radiating elements in the plurality of sets of arrays of radiating elements being disposed on an outer side of a respective one of the plurality of reflector plates, respectively; and

the signal processing apparatus according to any one of claims 1 to 17, wherein a beam forming network of the signal processing apparatus is connected to the plurality of sets of radiating element arrays, and the signal processing apparatus is disposed in a space inside the plurality of reflector plates.

19. The base station antenna of claim 18, wherein the reflector assembly is cylindrical.

20. The base station antenna of 18, wherein each output port of the beam forming network is connected to a group of radiating elements or a column of radiating elements in the plurality of groups of radiating element arrays.

As used herein, the terms "front," "back," "top," "bottom," "over," "under," and the like, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that such terms are interchangeable under appropriate circumstances such that the embodiments of the disclosure described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

As used herein, the word "exemplary" means "serving as an example, instance, or illustration," and not as a "model" that is to be reproduced exactly. Any implementation exemplarily described herein is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, the disclosure is not limited by any expressed or implied theory presented in the preceding technical field, background, utility model content, or detailed description.

As used herein, the term "substantially" is intended to encompass any minor variation resulting from design or manufacturing imperfections, tolerances of the device or components, environmental influences, and/or other factors. The word "substantially" also allows for differences from a perfect or ideal situation due to parasitics, noise, and other practical considerations that may exist in a practical implementation.

In addition, the foregoing description may refer to elements or nodes or features being "connected" or "coupled" together. As used herein, unless expressly stated otherwise, "connected" means that one element/node/feature is electrically, mechanically, logically, or otherwise connected (or in communication) with another element/node/feature. Similarly, unless expressly stated otherwise, "coupled" means that one element/node/feature may be mechanically, electrically, logically or otherwise joined to another element/node/feature in a direct or indirect manner to allow interaction, even though the two features may not be directly connected. That is, to "couple" is intended to include both direct and indirect joining of elements or other features, including connection with one or more intermediate elements.

In addition, "first," "second," and like terms may also be used herein for reference purposes only, and thus are not intended to be limiting. For example, the terms "first," "second," and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.

It should also be noted that, as used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" and any other variations thereof, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In the present disclosure, the term "providing" is used broadly to encompass all ways of obtaining an object, and thus "providing an object" includes, but is not limited to, "purchasing," "preparing/manufacturing," "arranging/setting," "installing/assembling," and/or "ordering" the object, and the like.

Those skilled in the art will also appreciate that the boundaries between the above described operations are merely illustrative. Multiple operations may be combined into a single operation, single operations may be distributed in additional operations, and operations may be performed at least partially overlapping in time. Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be altered in various other embodiments. However, other modifications, variations, and alternatives are also possible. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. The embodiments disclosed herein may be combined with each other in any combination without departing from the spirit and scope of the present disclosure. Those skilled in the art will also appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A signal processing apparatus, characterized in that the signal processing apparatus comprises:

a substrate;

a beam forming network disposed on one side of the substrate; and

2. The signal processing apparatus of claim 1, wherein at least a portion of the beamforming network, at least a portion of the calibration circuitry, and the connecting trace are integrally formed.

3. The signal processing apparatus of claim 1, wherein the connecting trace is part of a trace forming at least one of the beamforming network and the calibration circuit.

4. The signal processing apparatus of claim 1, wherein the shape of the connection trace is configured to cause impedance matching at a connection of the beamforming network and the calibration circuit.

5. The signal processing apparatus of claim 4, wherein the connection trace comprises a bend.

6. The signal processing apparatus of claim 5, wherein a length of the bend is configured to cause impedance matching at a connection of the beamforming network and the calibration circuit.

7. The signal processing apparatus of claim 1 wherein the beam-forming network comprises a plurality of input ports, the calibration circuit comprises a plurality of output ports, and each of the plurality of input ports of the beam-forming network is connected to a respective one of the plurality of output ports of the calibration circuit via a respective one of the connecting traces.

8. A signal processing arrangement as claimed in claim 7, characterized in that a plurality of connection tracks extend parallel to each other on the substrate.

9. The signal processing apparatus according to claim 7, wherein a plurality of connection traces are uniformly distributed on the substrate in a direction perpendicular to a direction in which the connection traces extend.

11. The signal processing apparatus of claim 10, wherein the passive beamforming network comprises a Butler matrix.

12. The signal processing apparatus of claim 11, wherein the butler matrix comprises first, second, third, and fourth hybrid couplers and first and second phase retarders, wherein:

13. The signal processing apparatus of claim 12, wherein the first phase retarder and the second phase retarder are each 45 ° phase delay traces.

14. The signal processing apparatus of claim 1, wherein the calibration circuit comprises:

17. The signal processing apparatus of claim 14 wherein each distribution path connected between each input port and output port of the power splitter is of equal length.

18. A base station antenna, characterized in that the base station antenna comprises:

a signal processing apparatus according to any one of claims 1 to 17, wherein a beam forming network of the signal processing apparatus is connected to the plurality of sets of radiating element arrays, and the signal processing apparatus is disposed in a space inside the plurality of reflector plates.

20. The base station antenna of claim 18, wherein each output port of the beam forming network is connected to a respective one of the plurality of sets of radiating elements or a respective column of radiating elements.