阅读说明：本技术 一种基于Butler矩阵的集成多波束馈电网络 (Integrated multi-beam feed network based on Butler matrix ) 是由 李越 张永健 刘培钦 张志军 于 2020-04-27 设计创作，主要内容包括：本发明公开了一种基于Butler矩阵的集成多波束馈电网络,并基于此设计了一种双馈电网络框架,由两类基于Butler矩阵的集成多波束馈电网络构成。每一类馈电网络各包含有2个输入端口及8个输出端口,分别采用了2个加载移相器的功分器、4个定向耦合器、6个交叉耦合器与8个相位补偿器,通过设置不同的移相器单元,两类多波束馈电网络可分别在输出端口处形成±22.5°或±67.5°两组相反的梯度分布相位。双馈电网络框架共包含有4个输入端口与16个输出端口,可设置在射频端口与天线阵列的天线端口之间,采用微带电路形式实现,与天线单元阵列集成并能够组合形成四个波束实现区域覆盖。(The invention discloses an integrated multi-beam feed network based on a Butler matrix, and designs a double feed network framework based on the integrated multi-beam feed network, wherein the double feed network framework is composed of two types of integrated multi-beam feed networks based on the Butler matrix. Each type of feed network comprises 2 input ports and 8 output ports, 2 power dividers for loading phase shifters, 4 directional couplers, 6 cross couplers and 8 phase compensators are respectively adopted, and two types of multi-beam feed networks can respectively form two groups of opposite gradient distribution phases of +/-22.5 degrees or +/-67.5 degrees at the output ports by arranging different phase shifter units. The double feed network frame comprises 4 input ports and 16 output ports in total, can be arranged between a radio frequency port and an antenna port of the antenna array, is realized in a microstrip circuit mode, is integrated with the antenna unit array and can be combined to form four beams to realize area coverage.)

1. An integrated multi-beam feed network based on a Butler matrix is characterized by comprising 2 input ports, 8 output ports, 2 power dividers loading phase shifters, 4 directional couplers, 6 cross couplers and 8 phase compensators, wherein:

the 2 power dividers are all one-to-four power dividers, an input port #01 is connected with the input end of a first power divider (101), an input port #02 is connected with the input end of a second power divider (201), and the output end of the first power divider (101) and the output end of the second power divider (201) are respectively connected with the input ends of the 4 directional couplers;

in 4 directional couplers, 6 cross couplers and 8 phase compensators, one output port of a directional coupler I (7) is directly connected with a phase compensator I (13), and the other output port is connected with a phase compensator V (17) through a cross coupler I (121), a cross coupler II (122) and a cross coupler III (123) in sequence; one output port of the directional coupler II (8) is connected with the phase compensator II (14) through a cross coupler I (121), and the other output port is connected with the phase compensator six (18) through a cross coupler IV (124) and a cross coupler V (125) in sequence; one output port of the directional coupler III (9) is connected with the phase compensator III (15) sequentially through a cross coupler IV (124) and a cross coupler II (122), and the other output port is connected with the phase compensator VII (19) through a cross coupler VI (126); one output port of the directional coupler IV (10) is connected with the phase compensator IV (16) sequentially through a cross coupler VI (126), a cross coupler V (125) and a cross coupler III (123), and the other output port of the directional coupler IV (10) is directly connected with the phase compensator eight (20);

and the output ends of the 8 phase compensators are respectively connected with 1 output port.

2. The Butler matrix-based integrated multi-beam feed network of claim 1, wherein the first power divider (101) comprises phase shifters a-one (1), B-one (3), and B-two (4), and the second power divider (201) comprises phase shifters a-two (2), B-three (5), and B-four (6), wherein:

the phase shifters a (1) and a (2) are 45 ° phase shifters, and the phase shifters B (3), B (4), B (5) and B (6) are 22.5 ° phase shifters, thereby forming a class a feed network, so that signals input from the input port #01 or the input port #02 can form 22.5 ° or-22.5 ° gradient phase distributions among the 8 output ports;

alternatively, the phase shifters a-1 and a-two (2) are 135 ° phase shifters, and the phase shifters B-3, B-two (4), B-three (5) and B-four (6) are 67.5 ° phase shifters, thereby forming a class B feed network, so that a signal input from the input port #01 or the input port #02 can form a gradient phase distribution of 67.5 ° or-67.5 ° between the 8 output ports, respectively.

3. The Butler matrix-based integrated multi-beam feed network according to claim 2, wherein the input port #01 is connected to the input of phase shifter a-i (1), the input of phase shifter B-i (4) and the input of directional coupler four (10), one output of the phase shifter a-i (1) is connected to the input of directional coupler two (8), the other output is connected to the input of phase shifter B-i (3), the output of phase shifter B-i (3) is connected to the input of directional coupler one (7), and the output of phase shifter B-i (4) is connected to the input of directional coupler three (9);

the input port #02 is connected with an input end of the phase shifter A two (2), an input end of the phase shifter B three (5) and an input end of the directional coupler I (7), one output end of the phase shifter A two (2) is connected with an input end of the directional coupler III (9), the other output end of the phase shifter A two (2) is connected with an input end of the phase shifter B four (6), an output end of the phase shifter B four (6) is connected with an input end of the directional coupler IV (10), and an output end of the phase shifter B three (5) is connected with an input end of the directional coupler II (8).

4. The Butler matrix-based integrated multi-beam feed network according to claim 2, wherein the class a and B feed networks are combined into a feed network with 4 input ports, 16 output ports, forming four phase gradient distributions at the output ports, respectively ± 22.5 ° and ± 67.5 °.

5. The integrated multi-beam feed network based on the Butler matrix according to the claim 1, 2, 3 or 4, characterized in that the integrated multi-beam feed network is arranged between the radio frequency ports and the antenna ports of the antenna array, is realized in the form of microstrip circuit, and is processed on the upper and lower printed circuit boards which are adhered together back to back.

6. The Butler matrix-based integrated multi-beam feed network of claim 5, wherein each phase shifter in each power splitter and each phase compensator are each formed by microstrip delay lines of different lengths, and each directional coupler and each cross coupler are each in a chip structure.

7. The Butler matrix-based integrated multi-beam feed network according to claim 5, wherein each directional coupler, each phase compensator and one power divider (101) are arranged on an upper layer printed circuit board, the second power divider (201) is arranged on a lower layer printed circuit board and is connected to the corresponding directional coupler through a jumper (11) connecting the two layers of printed circuit boards, and the jumper (11) is a metal column communicated with circuits of the upper and lower layers of printed circuit boards.

8. The Butler matrix-based integrated multi-beam feed network according to claim 5, wherein 4A-type feed network antenna sub-arrays (24) and 4B-type feed network antenna sub-arrays (25) are distributed on a support frame (23) to form a system-level antenna array, the antenna sub-arrays are spaced apart by 57mm, namely half wavelength of electromagnetic waves in vacuum at 2.6GHz, so as to ensure isolation between the sub-arrays, a metal plate is arranged behind each antenna sub-array to enhance front-to-back ratio of a radiation pattern of the antenna array, and the antenna array comprises 16 input ports and 64 antenna units, wherein 4 input ports correspond to +7 ° main beams, 4 input ports correspond to-7 ° main beams, 4 input ports correspond to +21 ° main beams, and 4 input ports correspond to-21 ° main beams.

Technical Field

The invention belongs to the technical field of microwave engineering, and particularly relates to an integrated multi-beam feed network based on a Butler matrix.

Background

In general, an N × N Butler matrix, that is, a Butler matrix having N input ports and N output ports, includes a certain number of phase shifters and directional couplers, and by appropriate arrangement of these devices, N phase distributions can be formed between the output ports, so that the antenna array can implement N beams.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide an integrated multi-beam feed network based on a Butler matrix, and through redesigning the feed network, the number of input ports is reduced to one fourth of the number of the input ports of the traditional network, and finally the feed network with a low section, a compact structure and easy integration is realized.

In order to achieve the purpose, the invention adopts the technical scheme that:

an integrated multi-beam feed network based on a Butler matrix comprises 2 input ports, 8 output ports, 2 power dividers loaded with phase shifters, 4 directional couplers, 6 cross couplers and 8 phase compensators, wherein the traditional Butler feed network is optimized by adopting the structure of the power dividers loaded with the phase shifters.

Wherein:

the 2 power dividers are all one-to-four power dividers, an input port #01 is connected with the input end of a first power divider 101, an input port #02 is connected with the input end of a second power divider 201, and the output end of the first power divider 101 and the output end of the second power divider 201 are respectively connected with the input ends of the 4 directional couplers;

in 4 directional couplers, 6 cross couplers and 8 phase compensators, one output port of a first directional coupler 7 is directly connected with a first phase compensator 13, and the other output port is connected with a fifth phase compensator 17 sequentially through a first cross coupler 121, a second cross coupler 122 and a third cross coupler 123; one output port of the second directional coupler 8 is connected with the second phase compensator 14 through a first cross coupler 121, and the other output port is connected with the sixth phase compensator 18 through a fourth cross coupler 124 and a fifth cross coupler 125 in sequence; one output port of the directional coupler III 9 is connected with the phase compensator III 15 through a cross coupler IV 124 and a cross coupler II 122 in sequence, and the other output port is connected with the phase compensator VII 19 through a cross coupler VI 126; one output port of the directional coupler IV 10 is connected with the phase compensator IV 16 sequentially through a cross coupler VI 126, a cross coupler V125 and a cross coupler III 123, and the other output port of the directional coupler IV is directly connected with the phase compensator V20;

and the output ends of the 8 phase compensators are respectively connected with 1 output port.

The first power divider 101 includes a phase shifter a 1, a phase shifter B3, and a phase shifter B4, and the second power divider 201 includes a phase shifter a 2, a phase shifter B5, and a phase shifter B6, where:

the phase shifters a 1 and a 2 are 45 ° phase shifters, and the phase shifters B3, B4, B three 5 and B four 6 are 22.5 ° phase shifters, thereby forming a class a feed network, so that signals input from the input port #01 or the input port #02 can form 22.5 ° or-22.5 ° gradient phase distributions among the 8 output ports;

alternatively, the phase shifters a 1 and a 2 are 135 ° phase shifters, and the phase shifters B3, B4, B three 5, and B four 6 are 67.5 ° phase shifters, thereby forming a class B feed network, so that a signal input from the input port #01 or the input port #02 can form a gradient phase distribution of 67.5 ° or-67.5 ° between the 8 output ports.

Each type of network comprises 2 input ports and 8 output ports, and the number of the input ports is reduced to be one fourth of that of the traditional network.

The input port #01 is connected with the input end of the phase shifter A-1, the input end of the phase shifter B-4 and the input end of the directional coupler IV 10, one output end of the phase shifter A-1 is connected with the input end of the directional coupler II 8, the other output end of the phase shifter A-1 is connected with the input end of the phase shifter B-3, the output end of the phase shifter B-3 is connected with the input end of the directional coupler I7, and the output end of the phase shifter B-4 is connected with the input end of the directional coupler III 9;

the input port #02 is connected with an input end of the phase shifter a two 2, an input end of the phase shifter B three 5 and an input end of the directional coupler one 7, one output end of the phase shifter a two 2 is connected with an input end of the directional coupler three 9, the other output end of the phase shifter a two 2 is connected with an input end of the phase shifter B four 6, an output end of the phase shifter B four 6 is connected with an input end of the directional coupler four 10, and an output end of the phase shifter B three 5 is connected with an input end of the directional coupler two 8.

The A-type feed network and the B-type feed network can be combined into a feed network with 4 input ports and 16 output ports, and four phase gradient distributions of +/-22.5 degrees and +/-67.5 degrees are formed at the output ports.

The integrated multi-beam feed network based on the Butler matrix is arranged between a radio frequency port and an antenna port of an antenna array, is realized in a microstrip circuit mode, is processed on an upper layer of printed circuit board and a lower layer of printed circuit board which are adhered together back to back, and can be integrated with an antenna unit on a dielectric plate.

Each phase shifter and each phase compensator in each power divider respectively consist of microstrip delay lines with different lengths, and each directional coupler and each cross coupler are of chip structures.

Each directional coupler, each phase compensator and the first power divider 101 are arranged on an upper-layer printed circuit board, the second power divider 201 is arranged on a lower-layer printed circuit board and is connected to the corresponding directional coupler through a jumper 11 for connecting the two layers of printed circuit boards, and the jumper 11 is a metal column for communicating circuits of the upper-layer printed circuit board and the lower-layer printed circuit board.

Compared with the prior art, the invention has the beneficial effects that:

and (I) a power divider structure loaded with a phase shifter is adopted to replace part of a Butler matrix structure, so that the feed network is simplified, the number of directional couplers and the number of the phase shifters are reduced, and the loss of the feed network is further reduced.

And (II) a feasible feed network processing scheme is provided, the simple integration of the multi-beam feed network and the antenna unit is realized, and the volume of the system is reduced.

And (III) two types of integrated multi-beam feed networks based on the Butler matrix are adopted, four different phase distributions among output ports are realized, and the practical application significance is realized.

Drawings

Fig. 1 is a schematic diagram of a topological structure of an integrated multi-beam feed network based on a Butler matrix provided by the invention.

Fig. 2 is a structural diagram of an antenna array implementation of the integrated multi-beam feeding network provided in the present invention, wherein (a) is a schematic front view, and (b) is a schematic back view.

Fig. 3 is a test S-parameter curve for a class a antenna array implementation.

Fig. 4 shows simulation and actual measurement results of the structure pattern of the type a and type B antenna arrays.

Fig. 5 is a schematic diagram of a system level antenna array employing class a and class B antenna array implementations.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the drawings and examples.

Referring to fig. 1, a schematic view of a topology structure of an integrated multi-beam feed network based on a Butler matrix provided by the present invention is shown. The integrated multi-beam feed network is arranged between a radio frequency port and an antenna port of an antenna array and is realized in a micro-strip circuit mode, the network is divided into two types, namely an A-type feed network and a B-type feed network, and the two types of networks have the same structure.

Each type of feed network mainly comprises 2 input ports, 8 output ports, 2 power dividers loaded with phase shifters, 4 directional couplers, 6 cross couplers and 8 phase compensators. Each phase shifter and each phase compensator in each power divider are respectively composed of microstrip delay lines with different lengths, and each directional coupler and each cross coupler are of chip structures.

Wherein:

the 2 power dividers are four-in-one power dividers, an input port #01 is connected with the input end of the first power divider 101, an input port #02 is connected with the input end of the second power divider 201, and the output end of the first power divider 101 and the output end of the second power divider 201 are connected with the input ends of the 4 directional couplers respectively.

In 4 directional couplers, 6 cross couplers and 8 phase compensators, one output port of a first directional coupler 7 is directly connected with a first phase compensator 13, and the other output port is connected with a fifth phase compensator 17 sequentially through a first cross coupler 121, a second cross coupler 122 and a third cross coupler 123; one output port of the second directional coupler 8 is connected with the second phase compensator 14 through a first cross coupler 121, and the other output port is connected with the sixth phase compensator 18 through a fourth cross coupler 124 and a fifth cross coupler 125 in sequence; one output port of the directional coupler III 9 is connected with the phase compensator III 15 through a cross coupler IV 124 and a cross coupler II 122 in sequence, and the other output port is connected with the phase compensator VII 19 through a cross coupler VI 126; one output port of the directional coupler IV 10 is connected with the phase compensator IV 16 sequentially through a cross coupler VI 126, a cross coupler V125 and a cross coupler III 123, and the other output port of the directional coupler IV is directly connected with the phase compensator V20;

the output end of the first phase compensator 13 is connected with the output port #01, the output end of the second phase compensator 14 is connected with the output port #02, the output end of the third phase compensator 15 is connected with the output port #03, the output end of the fourth phase compensator 16 is connected with the output port #04, the output end of the fifth phase compensator 17 is connected with the output port #05, the output end of the sixth phase compensator 18 is connected with the output port #06, the output end of the seventh phase compensator 19 is connected with the output port #07, and the output end of the eighth phase compensator 20 is connected with the output port # 08.

Specifically, the first power divider 101 includes a first phase shifter a 1, a first phase shifter B3, and a second phase shifter B4, and the second power divider 201 includes a second phase shifter a 2, a third phase shifter B5, and a fourth phase shifter B6. The input port #01 is connected with the input end of the phase shifter A-1, the input end of the phase shifter B-4 and the input end of the directional coupler IV 10, one output end of the phase shifter A-1 is connected with the input end of the directional coupler II 8, the other output end of the phase shifter A-1 is connected with the input end of the phase shifter B-3, the output end of the phase shifter B-3 is connected with the input end of the directional coupler I7, and the output end of the phase shifter B-4 is connected with the input end of the directional coupler III; input port #02 is connected to the input terminal of phase shifter a two 2, the input terminal of phase shifter B three 5, and the input terminal of directional coupler one 7, one output terminal of phase shifter a two 2 is connected to the input terminal of directional coupler three 9, the other output terminal is connected to the input terminal of phase shifter B four 6, the output terminal of phase shifter B four 6 is connected to the input terminal of directional coupler four 10, and the output terminal of phase shifter B three 5 is connected to the input terminal of directional coupler two 8.

When the phase shifters a 1 and a 2 are 45 ° phase shifters, and the phase shifters B3, B4, B three 5, and B four 6 are 22.5 ° phase shifters, a class a feed network is formed, so that signals input from the input port #01 or the input port #02 can form 22.5 ° or-22.5 ° phase distributions among the input ports of the 4 directional couplers, the input ports of the 8 phase compensators, and the 8 output ports, respectively.

When the phase shifters a 1 and a 2 are 135 ° phase shifters, and the phase shifters B3, B4, B three 5, and B four 6 are 67.5 ° phase shifters, a class B feeding network is formed, so that signals input from the input port #01 or the input port #02 can form a 67.5 ° or-67.5 ° phase distribution among the input ports of 4 directional couplers, the input ports of 8 phase compensators, and the 8 output ports, respectively.

The A-type feed network and the B-type feed network can be combined into a double feed network frame with 4 input ports and 16 output ports, and four phase gradient distributions of +/-22.5 degrees and +/-67.5 degrees are formed at the output ports.

The feed network can be processed on an upper printed circuit board and a lower printed circuit board which are adhered together back to back, is integrated with the antenna unit on the dielectric plate, and can be combined to form four beams to realize area coverage. Each directional coupler, each phase compensator and the first power divider 101 are arranged on an upper-layer printed circuit board, the second power divider 201 is arranged on a lower-layer printed circuit board and is connected to the corresponding directional coupler through a jumper 11 for connecting the two layers of printed circuit boards, and the jumper 11 is a metal column for communicating circuits of the upper-layer printed circuit board and the lower-layer printed circuit board.

That is, the invention adopts the power divider network loaded with the phase shifter to replace part of the traditional 8 × 8Butler matrix network, and can respectively arrange two sets of power divider networks on two dielectric plates adhered together back to back (the solid line part is arranged on the upper dielectric plate, the virtual line part is arranged on the lower dielectric plate in fig. 1), and directly or through a jumper to connect with the directional coupler group, and a phase compensator formed by a cross coupler chip and a delay line is adopted between the directional coupler group and the output port, the use of the cross coupler chip solves the problems of design complexity and volume increase possibly caused by the microstrip line cross structure, the use of the phase compensator solves the problem of phase offset error introduced by the directional coupler chip and the cross coupler chip, and the corresponding relation of phase distribution formed between each input port and each output port is shown in table 1 and table 2.

TABLE 1 corresponding relation of input and output phase distribution of A-type feed network

TABLE 2 corresponding relation of input and output phase distribution of B-type feed network

In tables 1 and 2, a radio frequency signal of 2.6GHz is input to an input port, and in a class a feed network, when a signal is input from an input port #01, signals with a phase gradient of 90 ° to-67.5 ° are sequentially output from output ports #01 to # 08; when a signal is input from the input port #02, the output ports #01 to #08 output signals having-67.5 ° to 90 ° phase gradients in sequence. In the B-type feed network, when a signal is input from an input port #01, output ports #01 to #08 output signals with-90-157.5-degree phase gradients in sequence; when a signal is input from the input port #02, the output ports #01 to #08 output signals having a phase gradient of 157.5 ° to 90 ° in sequence.

Referring to fig. 2, a structure diagram of an antenna array implementation of the integrated multi-beam feeding network provided in the present invention includes a schematic front view of an implementation structure in fig. 2(a) and a schematic back view of an implementation structure in fig. 2 (b). The dielectric constant of the dielectric plate is 2.65, the thickness is 1mm, and the width of the microstrip line is 2.6 mm. The power divider adopts a one-to-four Wilkinson power divider loaded with a phase shifter, the type of a directional coupler chip is Anaren Xinger 1P603AS, and the type of a cross coupler chip is Anaren Xinger X2 BS. The two types of feed networks are respectively connected with eight same dipole antenna units 21, the distance between the antenna units is 57mm, namely the half wavelength of electromagnetic waves in vacuum under 2.6GHz, and the isolation between the antenna units is ensured. Four different gradient phase distributions shown in tables 1 and 2 are formed among antenna arrays by respectively adopting A-type and B-type feed networks and inputting signals from an input port #01 to an input port #02, so that directional diagrams of four main beams are directed.

Referring to fig. 3, the implementation structures of the class a and class B antenna arrays have similar scattering characteristics because the other structures have similar compositions except for the structure adopted by the phase shifter, and a test S parameter curve of the implementation structure of the class a antenna array is given here. Wherein S11 represents the reflection coefficient of the antenna array at the input port 1, S22 represents the reflection coefficient of the antenna array at the input port 2, and S21 represents the isolation between the input port #01 and the input port #02, it can be seen that-10 dB impedance bandwidths of the two input ports can both cover a frequency band range around 2.6GHz, and the isolation between the two input ports in the frequency band is about-10 dB, which can meet the requirements of engineering application.

Referring to fig. 4, simulation and actual measurement results of the E-plane pattern of the structure implemented for the class a and class B antenna arrays. It can be seen that, for the class a feed network, when feeding from the input port #01, the main beam direction of the class a antenna array pattern is +7 °; when fed from input port #02, the main beam direction of the class a antenna array pattern is-7 °. For a B-type feed network, when feeding is carried out from the input port #01, the main beam direction of a B-type antenna array directional diagram is +21 degrees; when fed from input port #02, the main beam direction of the class B antenna array pattern is-21 °. The four beams can realize-3 dB beam coverage within an angle range of 60 degrees, and the communication angle range between the base station and the user in an actual application scene is met.

Referring to fig. 5, a schematic diagram of a system level antenna array using the type a and type B feeding network antenna structures is shown. The antenna array is arranged on the support frame 23 and can be divided into 8 antenna sub-arrays, wherein 4 antenna sub-arrays are A-type feed network antenna sub-arrays 24, 4 antenna sub-arrays are B-type feed network antenna sub-arrays 25, and the distance between the antenna sub-arrays is 57mm, namely the half wavelength of electromagnetic waves in vacuum under 2.6GHz, so that the isolation between the sub-arrays is ensured. A metal plate 22 is disposed behind each antenna element to enhance the front-to-back ratio of the antenna array radiation pattern. The antenna array comprises 16 input ports and 64 antenna units, wherein 4 input ports correspond to a main beam of +7 degrees, 4 input ports correspond to a main beam of-7 degrees, 4 input ports correspond to a main beam of +21 degrees, and 4 input ports correspond to a main beam of-21 degrees.

Based on the design of two types of feed networks, the feed network provided by the invention comprises 4 input ports and 16 output ports, and can realize area coverage through four beams of +/-7 degrees and +/-21 degrees, and the feed network provided by the invention adopts a printed circuit board manufacturing mode, is easy to process and integrate and has good application prospect.