CN106505288B - Thirty-two-path waveguide E-surface power divider - Google Patents
Thirty-two-path waveguide E-surface power divider Download PDFInfo
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- CN106505288B CN106505288B CN201611102183.3A CN201611102183A CN106505288B CN 106505288 B CN106505288 B CN 106505288B CN 201611102183 A CN201611102183 A CN 201611102183A CN 106505288 B CN106505288 B CN 106505288B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P5/00—Coupling devices of the waveguide type
- H01P5/12—Coupling devices having more than two ports
- H01P5/16—Conjugate devices, i.e. devices having at least one port decoupled from one other port
- H01P5/18—Conjugate devices, i.e. devices having at least one port decoupled from one other port consisting of two coupled guides, e.g. directional couplers
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Abstract
The invention belongs to the technical field of microwave communication, and particularly relates to a thirty-two-path waveguide E-surface power divider. The invention comprises two groups of sixteen-path power dividers which are distributed in a left-right mirror image manner; each sixteen-path sub power divider comprises a first waveguide E-surface power divider and a second waveguide E-surface power divider; a first E-surface waveguide directional coupler is arranged at the position of the first waveguide E-surface power divider, and a second E-surface waveguide directional coupler is arranged between the first waveguide E-surface power divider and the second waveguide E-surface power divider; the third E-plane waveguide directional coupler is connected with the first E-plane waveguide directional coupler and the second E-plane waveguide directional coupler; each E-surface waveguide directional coupler comprises a first rectangular waveguide and a second rectangular waveguide which are of an E-surface coupling structure, and the second rectangular waveguide is provided with a step section for realizing a broadband phase-compensating function. The invention has the advantages of high broadband, large power dividing ratio, small amplitude fluctuation and good phase consistency, and can effectively improve the amplitude consistency and the phase consistency of the current thirty-two-path power divider.
Description
Technical Field
The invention belongs to the technical field of microwave communication, and particularly relates to a thirty-two-path waveguide E-surface power divider.
Background
The power divider is an antenna feeder device widely applied in modern communication, and the traditional power dividers are of Wilkinson type, E-surface waveguide type, H-surface waveguide type and the like. The Wilkinson power divider has the advantages of low section and miniaturization, but the microstrip transmission line has low power capacity and large dielectric loss, so that the application of the microstrip transmission line in occasions with high power requirements is limited. Waveguide power splitters are favored for their excellent characteristics, such as low loss, high power capacity, and wide transmission bandwidth, and are widely used in high-power systems, such as radars and satellites. In the waveguide power divider: the H-plane power divider has the defect of difficult miniaturization due to the adoption of waveguide broadside for distribution and larger transverse size. The E-surface power divider adopts waveguide narrow-edge power distribution, has the advantages of power capacity and miniaturization, and meets the requirements of miniaturization and compactness of the existing equipment. However, the conventional E-plane power divider has the problems of narrow bandwidth, large amplitude fluctuation and poor phase consistency of each port, which is especially the problem of large amplitude fluctuation when applied to the power divider with a large power dividing ratio. Whether a waveguide E-plane power divider with high broadband, large power division ratio, small amplitude fluctuation and good phase consistency can be found out, so that the amplitude consistency and the phase consistency of the multi-path power divider are effectively improved, the problem of large amplitude fluctuation of the power divider with large power division ratio and the design requirement of realizing broadband are synchronously solved, and the technical problem to be solved by technical personnel in the field in recent years is urgently solved.
Disclosure of Invention
One of the objectives of the present invention is to overcome the above-mentioned deficiencies of the prior art, and to provide a thirty-two-way waveguide E-plane power divider with a reasonable and practical structure, which has the advantages of high bandwidth, large power dividing ratio, small amplitude fluctuation and good phase consistency, and can effectively improve the amplitude consistency and phase consistency of the current thirty-two-way power divider, and synchronously solve the problem of large amplitude fluctuation of the power divider with large power dividing ratio and meet the design requirement of wide bandwidth.
In order to achieve the purpose, the invention adopts the following technical scheme:
a thirty-two-way waveguide E-surface power divider comprises two groups of sixteen-way sub power dividers which are distributed in a left-right mirror image mode, wherein output ports of the two groups of sixteen-way sub power dividers are combined together to form thirty-two output ports of the power divider based on Taylor distribution; each group of sixteen paths of sub power dividers comprises a group of asymmetrically arranged first waveguide E-surface power dividers and a group of symmetrically arranged second waveguide E-surface power dividers which are sequentially distributed along the mirror direction, and the two groups of second waveguide E-surface power dividers are adjacently arranged; the first waveguide E-surface power divider is a four-stage power dividing network formed by E-T branch waveguide combinations with different power dividing ratios, and the second waveguide E-surface power divider is a three-stage power dividing network formed by E-T branch waveguide combinations with different power dividing ratios; a first E-surface waveguide directional coupler is arranged between the last-stage E-T branch waveguide of the first waveguide E-surface power divider and the front three-stage power dividing network, and a second E-surface waveguide directional coupler is arranged between the first waveguide E-surface power divider and the second waveguide E-surface power divider; a coupling port C3 of the first E-plane waveguide directional coupler is connected with the input end of the front three-stage power distribution network of the first waveguide E-plane power divider, and a through port C2 is connected with the input end of the last stage E-T branch waveguide of the first waveguide E-plane power divider; a coupling port C3 of the second E-plane waveguide directional coupler is connected with an input port C1 of the first E-plane waveguide directional coupler, and a through port C2 is connected with the input end of the three-stage power distribution network at the second E-plane waveguide power divider; the power divider further comprises a third E-plane waveguide directional coupler used for connecting two groups of sixteen-path sub-power dividers, wherein a coupling port C3 and a through port C2 of the third E-plane waveguide directional coupler are respectively connected with input ports C3926 of the first E-plane waveguide directional coupler and the second E-plane waveguide directional coupler;
each E-surface waveguide directional coupler comprises a first rectangular waveguide and a second rectangular waveguide which are parallel to each other, coupling gaps are arranged on the coupling surfaces of the first rectangular waveguide and the second rectangular waveguide, and an E-surface coupling structure between the two waveguides is formed by three branch lines which are parallel to each other; an input port C1 and a through port C2 are respectively arranged at two ends of the first rectangular waveguide, an isolation port C4 and a coupling port C3 are respectively arranged at two ends of the second rectangular waveguide, and the input port C1 and the isolation port C4 are at the same end; a step section for realizing a broadband phase supplementing function is arranged at a waveguide section between the coupling port C3 on the second rectangular waveguide and a branch line closest to the coupling port C3, and the step section is formed by two side plates of opposite coupling surfaces on the second rectangular waveguide in a step-shaped distribution; the ladder section comprises two groups of three-section ladder structures, and the narrow ends of the two sections of three-section ladder structures are connected with each other.
And a pair of rectangular notches are arranged at the positions of the E-T branch waveguides, the rectangular notches are distributed at the right-angle joint of the branch arm and the two end arms on each E-T branch waveguide, and the rectangular notches are formed by vertically and concavely arranging the corresponding surfaces of the two end arms.
And an external chamfer angle is arranged at the L-shaped corner of each E-T branch waveguide.
The coupling degree of the first E-plane waveguide directional coupler is 3.38 dB; the degree of coupling of the second E-plane waveguide directional coupler is 8.18dB, and the degree of coupling of the third E-plane waveguide directional coupler 10c is 3 dB.
The invention has the beneficial effects that:
1) on one hand, the E-T branch waveguide is adopted as a basic frame, so that different power division ratios of the whole network are simpler to realize; on the other hand, different amplitude weighting modes are well realized by adopting a topological structure based on Taylor distribution. More importantly, the E-plane waveguide directional coupler with the broadband phase compensation characteristic is adopted, and when the E-plane waveguide directional coupler is used, the aim of adjusting different coupling degrees can be fulfilled by adjusting the widths of three parallel branch lines, wherein the width direction is parallel to the length direction of the first rectangular waveguide. Specifically, the phase consistency of the straight-through end and the coupling end of the coupler can be ensured by adjusting the waveguide broadside at the step section with broadband phase compensation characteristics, namely the width and the length of the step at the step section. The coupler has the advantages of simple and compact structure, high compactness, easy processing, wide frequency band, low loss and good power distribution consistency, ensures the design performance of the whole network at a large power division ratio, effectively reduces the fluctuation of amplitude, and can effectively ensure the consistency of the phase of each port. The VSWR of the input port of the whole waveguide power divider one-to-thirty-two is low, the amplitude fluctuation of each output port is small, the phase error is within +/-2 degrees, the requirement of good consistency is met, and the whole power divider network can be widely applied to high-power radar, satellite and other systems.
2) And two groups of second waveguide E-plane power dividers are arranged adjacently, namely in the network topology structure of the invention, two groups of symmetrically distributed one-to-eight power dividers are adopted in the middle, and two groups of asymmetric one-to-eight power dividers are adopted on the outer side. The purpose of the network topology structure design is to rationalize the power division ratio of each stage of power divider and avoid the condition of large power division ratio as much as possible on the premise of ensuring that the energy of each port is distributed according to the Taylor-30 dB amplitude weighting. The network topology structure can effectively reduce the design difficulty of each stage of power divider and the in-band amplitude fluctuation caused by large power division ratio, finally can further reduce the amplitude fluctuation in the working bandwidth, and effectively realizes the amplitude weighting characteristic of each port.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is a schematic structural diagram of the sixteen-way sub power divider at the left side of fig. 1;
fig. 3 is a schematic structural diagram of the E-plane power splitter at the left side of fig. 2, i.e., the first waveguide;
fig. 4 is a schematic structural diagram of the second waveguide E-plane power splitter at the right side of fig. 2;
FIG. 5 is a schematic diagram of the structure of an E-T branched waveguide;
FIG. 6 is a schematic structural diagram of an E-plane waveguide directional coupler;
FIG. 7 is a schematic structural view of the step section of the present invention;
FIG. 8 is a diagram of an amplitude distribution network topology of the present invention;
FIG. 9 is a VSWR test chart of the present invention;
FIG. 10 is a test plot of the amplitude curves of the ports of the present invention;
FIG. 11 is a phase curve test chart for each port of the present invention.
The corresponding relation between each reference number and each part name in the drawings is as follows:
a-sixteen path power divider
10 a-first E-plane waveguide directional coupler 10 b-second E-plane waveguide directional coupler
10 c-third E-plane waveguide directional coupler
11-first rectangular waveguide 12-second rectangular waveguide 13-branch line 14-step section
21-rectangular notch 22-corner cut
30-first waveguide E-plane power divider 40-second waveguide E-plane power divider
Detailed Description
For the purpose of understanding, the detailed construction and workflow of the present invention are described herein with reference to the accompanying drawings:
the specific structure of the invention, as shown in fig. 1-4, is that the power divider mainly comprises three parts: a sixteen-way sub power divider a located at the left side of fig. 1, a sixteen-way sub power divider a located at the right side of fig. 1, and a third E-plane waveguide directional coupler 10c with broadband phase-complementary characteristics; the two groups of sixteen-path sub power dividers a are in a left-right mirror image relationship in structure. The coupling degree of the third E-plane waveguide directional coupler 10c is 3dB, and the coupling port and the through port of the third E-plane waveguide directional coupler 10c and the input ports of the second E-plane waveguide directional couplers at the two groups of sixteen sub power dividers a are connected by a straight waveguide.
The specific composition and connection structure of the sixteen-path sub-power divider a are as follows:
the first waveguide E-plane power splitter 30, as shown in fig. 2-3, is composed of six E-T branch waveguides with different power ratios and a first E-plane waveguide directional coupler 10a with a broadband complementary phase characteristic. The whole topological network has four stages, five E-T branch waveguides of the first three stages form an asymmetric power distribution network structure, and the input end of the E-T branch waveguide of the last stage is connected with the input end of the power distribution network of the first three stages through a first E-plane waveguide directional coupler 10 a. The degree of coupling of the first E-plane waveguide directional coupler 10a is 3.38 dB.
The second waveguide E-plane power splitter 40 is composed of seven E-T branch waveguides with different power ratios, as shown in fig. 2 and 4, and the topology network has three stages in total and forms a symmetrical structure.
The second E-plane waveguide directional coupler 10b is used to connect the first waveguide E-plane power splitter 30 and the second waveguide E-plane power splitter 40, and has a coupling degree of 8.18 dB.
An E-plane waveguide directional coupler with broadband phase-complementary characteristics is shown in fig. 6 and 7, in which: c1 is the input port of the coupler, C2 is the pass-through port, C3 is the coupled port, and C4 is the isolated port. When in use, different coupling degree adjustments can be realized through the widths of the three branch lines 13 connecting the coupling surfaces of the first rectangular waveguide 11 and the second rectangular waveguide 12. And as shown in fig. 6, because a phase difference of 90 ° exists between the through port C2 and the coupling port C3, the planar structure of the stepped segment 14 for implementing broadband phase compensation is adopted to change the width of the wide side a of the waveguide to make the stepped transition to the widths a2 and a1, and implement phase compensation by synchronously adjusting the lengths L and Δ L of the corresponding segments, and finally ensure phase consistency of the through port C2 and the coupling port C3. After optimization by practical experiments, the following values can be selected: a 1-19.86 mm, a 2-20.86 mm, L-8 mm, Δ L-15 mm.
For the E-T branch waveguides of the sub-units constituting each power divider, as shown in fig. 5, when energy is input from the input port of the branch arm, the width and height of the rectangular notch 21 are adjusted, so that the two output ports at the two end arms output different energies, and thus the amplitude distribution adjustment of the power dividing network can be achieved.
The amplitude weighting distribution of the sixteen-path waveguide E-plane power splitter can be as shown in fig. 8, and through the amplitude weighting distribution, the antenna matched with the sixteen-path waveguide E-plane power splitter can realize a-30 dB side lobe design, and the design requirement of a low side lobe is met.
The test piece of the present invention is manufactured by using the above-mentioned amplitude weighted distribution and structure size, and the voltage standing wave ratio of the input port s0 of the test piece is tested, and the test result is shown in fig. 9: it can be seen from fig. 9 that in the frequency band range of 9.0 to 9.6GHz, the standing wave of the power divider is less than 1.4, and a better impedance matching characteristic is realized. The amplitude and the phase of each output port s1-s32 of the test piece within the working frequency band of 9.0-9.6 GHz are tested, and the test results are respectively shown in fig. 10 and fig. 11: as can be seen from FIG. 10, the amplitude fluctuation of each output port (s1-s32) is less than +/-0.5 dB, and a better amplitude distribution design is realized; as can be seen from fig. 11, the phase error of each output port (s1-s32) < ± 2 °, a good phase consistency requirement is achieved.
Claims (3)
1. A thirty-two-way waveguide E-surface power divider is characterized in that: the power divider comprises two groups of sixteen-path sub power dividers (a) which are distributed in a left-right mirror image manner, wherein output ports of the two groups of sixteen-path sub power dividers (a) are combined together to form thirty-two output ports of the power divider based on Taylor distribution; each group of sixteen paths of sub power dividers (a) comprises a group of asymmetrically arranged first waveguide E-surface power dividers (30) and a group of symmetrically arranged second waveguide E-surface power dividers (40) which are sequentially distributed along the mirror image direction, and the two groups of second waveguide E-surface power dividers (40) are adjacently arranged; the first waveguide E-surface power divider (30) is a four-stage power dividing network formed by E-T branch waveguide combinations with different power dividing ratios, and the second waveguide E-surface power divider (40) is a three-stage power dividing network formed by the E-T branch waveguide combinations with different power dividing ratios; a first E-surface waveguide directional coupler (10a) is arranged between the last-stage E-T branch waveguide of the first waveguide E-surface power divider (30) and the front-stage power dividing network, and a second E-surface waveguide directional coupler (10b) is arranged between the first waveguide E-surface power divider (30) and the second waveguide E-surface power divider (40); the coupling port C3 of the first E-plane waveguide directional coupler (10a) is connected with the input end of the front three-stage power splitting network of the first waveguide E-plane power splitter (30), and the through port C2 is connected with the input end of the last stage E-T branch waveguide of the first waveguide E-plane power splitter (30); the coupling port C3 of the second E-plane waveguide directional coupler (10b) is connected with the input port C1 of the first E-plane waveguide directional coupler (10a), and the through port C2 is connected with the input end of the three-stage power dividing network at the second waveguide E-plane power divider (40); the power divider also comprises a third E-plane waveguide directional coupler (10C) used for connecting two groups of sixteen-path sub-power dividers (a), wherein a coupling port C3 and a through port C2 of the third E-plane waveguide directional coupler (10C) are respectively connected with an input port C1 of a second E-plane waveguide directional coupler (10b) of the two groups of sixteen-path sub-power dividers;
each E-plane waveguide directional coupler comprises a first rectangular waveguide (11) and a second rectangular waveguide (12) which are parallel to each other, coupling gaps are arranged at the coupling surfaces of the first rectangular waveguide (11) and the second rectangular waveguide (12), and an E-plane coupling structure between the two waveguides is formed by three branch lines (13) which are parallel to each other; an input port C1 and a through port C2 are respectively arranged at two ends of the first rectangular waveguide (11), an isolation port C4 and a coupling port C3 are respectively arranged at two ends of the second rectangular waveguide (12), and the input port C1 and the isolation port C4 are at the same end; a step section (14) for realizing a broadband phase supplementing function is arranged at a waveguide section between a coupling port C3 on the second rectangular waveguide (12) and a branch line (13) closest to the coupling port C3, and the step section (14) is formed by the step distribution of two side plates of the opposite coupling surface on the second rectangular waveguide (12); the step section (14) comprises two groups of three-section step structures, and the narrow ends of the two groups of three-section step structures are connected with each other;
each E-T branch waveguide is provided with a pair of rectangular notches (21), the rectangular notches (21) are distributed at the right-angle joint of the branch arm and the two end arms on each E-T branch waveguide, and the rectangular notches (21) are formed by vertically and concavely arranging the corresponding surfaces of the two end arms.
2. The thirty-two way waveguide E-plane power divider according to claim 1, characterized in that: an external chamfer (22) is provided at the L-shaped corner of each E-T branch waveguide.
3. The thirty-two way waveguide E-plane power divider according to claim 1, characterized in that: the coupling degree of the first E-plane waveguide directional coupler (10a) is 3.38 dB; the coupling degree of the second E-plane waveguide directional coupler (10b) is 8.18dB, and the coupling degree of the third E-plane waveguide directional coupler (10c) is 3 dB.
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| CN111834728A (en) * | 2020-08-13 | 2020-10-27 | 郝艺益 | Broadband unequal-dividing power divider of coplanar waveguide circuit |
| CN115020954B (en) * | 2022-08-08 | 2022-11-08 | 南京天朗防务科技有限公司 | Taylor distribution power divider based on Wilkinson form and design method thereof |
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| CN202930551U (en) * | 2012-11-14 | 2013-05-08 | 广东隆伏通讯设备有限公司 | Novel ''communication in moving '' low contour satellite antenna radiant panel structure |
| CN103956586A (en) * | 2014-05-04 | 2014-07-30 | 广东盛路通信科技股份有限公司 | Flat panel array antenna |
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| CN202930551U (en) * | 2012-11-14 | 2013-05-08 | 广东隆伏通讯设备有限公司 | Novel ''communication in moving '' low contour satellite antenna radiant panel structure |
| CN103956586A (en) * | 2014-05-04 | 2014-07-30 | 广东盛路通信科技股份有限公司 | Flat panel array antenna |
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| Title |
|---|
| 一种新型八路波导功分器的设计;李霞等;《2016年全国军事微波、太赫兹、电磁兼容技术学术会议论文集》;20160817;正文第387-389页 * |
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