Ku-band waveguide three-way power distribution synthesizer

Abstract

The utility model discloses a Ku frequency band waveguide three-path power distribution synthesizer, which belongs to the technical field of microwave and millimeter wave, and comprises a shielding box, the left side wall of the shielding box is provided with a synthesis port, and the lower side wall of the shielding box is provided with three distribution ports; a branch waveguide unequal power divider, an L-shaped waveguide, an n-shaped waveguide, a coplanar magic T equal divider and a half waveguide-full waveguide right-angle transformation structure are arranged in the shielding box. The branch waveguide unequal power divider comprises a four-branch waveguide directional coupler, a waveguide-microstrip transition structure and a power resistance load, and the output power ratio of a straight-through output port to a coupling output port of the branch waveguide unequal power divider is 2: 1; the coplanar magic T equalizer comprises an E-T junction waveguide cavity, two equal branch waveguide cavities, a microstrip probe and a power resistance load, and outputs two paths of signals with equal amplitude and opposite phases. The filter provided by the utility model has the characteristics of simple structure, good amplitude and phase consistency, small insertion loss, good port standing wave and high isolation.

Description

Technical Field

[0001] The utility model relates to a Ku-band waveguide three-way power distribution synthesizer, belongs to the technical field of microwave and millimeter waves, and is particularly suitable for a Ku-band solid-state power amplifier applied to a satellite communication microwave channel. Background Art

[0002] At present, the maximum output power of domestic Ku-band GaN power amplifier chips is 35W (working in continuous wave mode). In order to obtain high power output, multiple chips must be combined for power. Traditional power combiners mainly use multi-level binary (2 n ) power synthesis method, but in actual engineering applications, the binary power synthesis method has the following shortcomings: using two (2 1 ) The combined output power is insufficient; using four (2 2 ) The combined output power margin is large, but doubling the number of chips results in increased power consumption and higher overall machine cost.

[0003] In response to the above problems, domestic and foreign scholars have conducted research on waveguide three-way equal power dividers. In July 2012, Caibo published "A Design of a Ka-band Waveguide Three-way Power Divider" in the journal "Telemetry and Remote Control". In this paper, a Ka-band three-way equal power divider was designed, which was realized by cascading two-stage waveguide ET branches, in which the first stage was equal power distribution and the second stage was unequal power distribution; in August 2012, Caibo applied for an invention patent "A Waveguide Three-way Equal Power Divider / Synthesizer", with application publication number CN102820509A and application publication date December 12, 2012. In 2022, several scholars improved the above structure in the Ku band. Lu Xiaona et al. published "Research on a One-to-Three In-Phase Waveguide Power Divider with Good Isolation" in the journal "Wireless Internet Technology" in September 2022, Huang Xuelong et al. published "Development of Ku-band 120W Miniaturized Power Amplifier Module" in the journal "Journal of Changchun Normal University" in October 2022, and Chen Guanjun et al. published "A New Ku-band Three-way Power Distribution / Synthesis Network" in the journal "Hebei Industrial Science and Technology" in November 2022. Among the structures proposed in the above papers, the structural disadvantage of Caibo, Chen Guanjun and Huang Xuelong et al. is that the isolation between the three output ports is poor, with an isolation of less than 10dB; Lu Xiaona et al. used a variant T-junction to improve the isolation between the two side arm ports to 18dB, but the isolation between the middle output port and the two side arm ports is still about 10dB. Moreover, the structure proposed by the above scholars has a serious problem. The standing wave ratio of the middle output port is very poor, and the return loss is only about 3dB. This means that when used as a combiner, half of the power of the power amplifier module connected to the middle port will be reflected, resulting in low power synthesis efficiency of the whole machine. Utility Model Content

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the utility model proposes a Ku-band waveguide three-way power distribution synthesizer, which has the characteristics of simple structure, good amplitude and phase consistency, small insertion loss, good port standing wave and high isolation.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A Ku-band waveguide three-way power distributor / synthesizer comprises a shielding box with a cavity inside; a synthesis port is arranged on the left side wall of the shielding box, and three distribution ports are arranged on the lower side wall; a branch waveguide unequal power divider, an "L"-shaped waveguide, a "J"-shaped waveguide, a coplanar magic T equal divider, and a half-waveguide-full-waveguide right-angle transformation structure are arranged inside the shielding box.

[0007] The branch waveguide unequal power divider includes a four-branch waveguide directional coupler, a waveguide-microstrip transition structure and a power resistor load. The synthetic port on the left wall of the shielding box is the input port of the branch waveguide unequal power divider; the upper right waveguide port of the branch waveguide unequal power divider is a straight-through output port, and the lower right waveguide port is a coupled output port; the lower left waveguide port is an isolation port, which is connected to the waveguide-microstrip transition structure and then connected to the power resistor load through a gold ribbon or multiple gold wires; a four-slit coupling array is provided between the input port and the coupled output port. The function of the branch waveguide unequal power divider is to distribute the input signal in unequal power, with the straight-through output port outputting two-thirds of the total power and the coupled output port outputting one-third of the total power, that is, the output power ratio of the straight-through output port to the coupled output port is 2:1.

[0008] The left port of the "L"-shaped waveguide is connected to the straight-through output port of the branch waveguide unequal power divider, and the lower port of the "L"-shaped waveguide is connected to the synthetic port of the coplanar magic T equal divider; the corners of the "L"-shaped waveguide are beveled at 45° to ensure that it has good return loss.

[0009] The upper port of the "J"-shaped waveguide is connected to the coupled output port of the branch waveguide unequal power divider; the lower port is one of the three distribution ports of the shielding box, located on the leftmost of the three ports. By adjusting the length of the "J"-shaped waveguide, the amplitude and phase of the output port are guaranteed to be consistent with the other two output ports of the shielding box.

[0010] The coplanar magic T divider includes an ET junction waveguide cavity and two equal branch waveguide cavities, and also includes a microstrip probe, one end of which is inserted into the ET junction waveguide cavity, and the other end is connected to a power resistor load; the connection between the equal branch waveguide cavity and the ET junction waveguide cavity is a half-size rectangular waveguide port, and the end port of the equal branch waveguide cavity is connected to a half-waveguide-full waveguide right-angle transformation structure. The function of the coplanar magic T divider is to output two equal-amplitude and anti-phase signals.

[0011] The half-waveguide-full-waveguide right-angle transformation structure realizes the transformation from a half-size waveguide to a full-size waveguide while realizing the right-angle turning of the waveguide, and has the characteristics of small transformation size, small insertion loss and excellent return loss.

[0012] Furthermore, the power resistor load is a gallium nitride power resistor load suitable for the Ku band and can withstand a power of 50W; the power resistor load is welded in the groove of the lower box body by gold-tin eutectic welding, and the end of the microstrip probe and the power resistor load are bonded and connected by a gold ribbon or multiple gold wires.

[0013] Furthermore, the shielding box is composed of a lower box body and an upper box body that are interlocked, the microstrip probe and the power resistor load are located in the lower box body, and the upper box body is provided with a corresponding cavity structure; the upper box body is provided with a plurality of countersunk holes, and the lower box body is provided with corresponding threaded holes; the upper box body and the lower box body are fixed by screws passing through the countersunk holes and the threaded holes to form a shielding box.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. The utility model proposes a waveguide three-way power splitter / synthesizer in the Ku band (13.75GHz-14.5GHz), which has the characteristics of simple structure, good amplitude and phase consistency, small insertion loss, good port standing wave and high isolation, and solves the problems of low isolation and poor standing wave ratio of the output port of the existing waveguide three-way power splitter / synthesizer.

[0016] 2. Under the condition of ensuring good heat dissipation, a single power resistor load can withstand 50W power, so the utility model can meet the needs of larger power synthesis; if there is a demand for higher power synthesis, the combining port of the shielding box can be exported from its upper side wall, and the isolation port of the branch waveguide unequal power divider can be exported from the left side wall of the shielding box, and an external high-power waveguide load can be connected to achieve it.

[0017] 3. The utility model solves the problem of binary (2 n) The shortcomings of the power synthesis method. The utility model is combined and cascaded with the traditional binary waveguide power distributor / synthesizer to achieve non-binary power synthesis of six, nine, twelve, eighteen, etc., that is, to achieve a reasonable selection of the number of power amplifier chips, which is conducive to improving the performance-power consumption ratio of the power amplifier and reducing the cost of the whole machine. The utility model is particularly suitable for application in Ku-band solid-state power amplifiers and has a high value of promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the appearance structure of the utility model;

[0019] Figure 2 It is a schematic diagram of the upper and lower box structures of the utility model;

[0020] Figure 3 It is a top view schematic diagram of the lower box body of the utility model;

[0021] Figure 4 This is a bottom view of the upper box body of the utility model;

[0022] Figure 5 It is a schematic diagram of the structure of the branch waveguide unequal power divider of the utility model;

[0023] Figure 6 This is a schematic diagram of the structure of the coplanar magic T divider of the utility model;

[0024] Figure 7 It is the amplitude curve diagram of output port 2 and port 4 of the utility model;

[0025] Figure 8 It is the phase curve diagram of output port 2 and port 4 of the utility model;

[0026] Fig. 9 It is the output port isolation curve diagram of the utility model;

[0027] Fig.10 It is a return loss curve diagram of the input and output ports of the utility model.

[0028] Because port 2 and port 3 of the shielding box are the output ports of the coplanar magic T divider, the two ports are symmetrical and the curves overlap, so Figure 7-10 The curve of port 3 is not shown, but the curve of port 2 can be used for reference. DETAILED DESCRIPTION

[0029] In order to facilitate those skilled in the art to understand the technical content of the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0030] See also Figure 1-Figure 6The utility model is a Ku-band waveguide three-way power distributor / synthesizer, whose shielding box is divided into a lower box body 1 and an upper box body 2; a synthesis port is arranged on the left side wall of the shielding box, and three distribution ports are arranged on the lower side wall; a branch waveguide unequal power divider 3, an "L"-shaped waveguide 4, a "J"-shaped waveguide 5, a coplanar magic T equal divider 6, and a half-waveguide-full-waveguide right-angle transformation structure 7 are arranged in the shielding box.

[0031] Furthermore, the branch waveguide unequal power divider 3 includes a four-branch waveguide directional coupler 8, a waveguide-microstrip transition structure 9 and a power resistor load 10. The synthetic port on the left side wall of the shielding box is the input port of the branch waveguide unequal power divider 3; the upper right waveguide port of the branch waveguide unequal power divider 3 is a straight-through output port, and the lower right waveguide port is a coupled output port; the lower left waveguide port is an isolation port, which is connected to the waveguide-microstrip transition structure 9, and then connected to the power resistor load 10 through a gold ribbon or multiple gold wires; a four-slit coupling array is provided between the input port and the coupled output port. The function of the branch waveguide unequal power divider 3 is to distribute the input signal in unequal power, with the straight-through output port outputting two-thirds of the total power, and the coupled output port outputting one-third of the total power, that is, the output power ratio of the straight-through output port to the coupled output port is 2:1.

[0032] Specifically, the waveguide-microstrip transition structure 9 adopts an E-plane probe transition form, and the central axis of the microstrip probe is one quarter wavelength away from the end of the waveguide cavity, and the specific value is 6.2 mm; the microstrip probe is placed on a RT / duroid 5880 dielectric plate with a thickness of 0.508 mm.

[0033] Furthermore, the left port of the "L"-shaped waveguide 4 is connected to the straight-through output port of the branch waveguide unequal power divider 3, and the lower port of the "L"-shaped waveguide 4 is connected to the synthetic port of the coplanar magic T divider 6; the corners of the "L"-shaped waveguide are beveled at 45°, and the transverse and longitudinal inscribed dimensions are both 6.34 mm, which can ensure that the "L"-shaped waveguide has an optimal return loss.

[0034] Furthermore, the upper port of the "J"-shaped waveguide 5 is connected to the coupled output port of the branch waveguide unequal power divider 3; the lower port is one of the three distribution ports of the shielding box, located at the leftmost of the three ports. By adjusting the length of the "J"-shaped waveguide, the amplitude and phase of the output port are guaranteed to be consistent with the other two output ports of the shielding box. In this embodiment, after the length is adjusted, the center line of the centered distribution port is 38mm away from the center line of the right distribution port, and the distance from the center line of the left distribution port is 38.13mm.

[0035] Furthermore, the coplanar magic T divider 6 includes an ET junction waveguide cavity 11 and two equal-branch waveguide cavities 12, and also includes a microstrip probe 13, one end of the microstrip probe 13 is inserted into the ET junction waveguide cavity 11, and the other end is connected to a power resistor load 10; the connection between the equal-branch waveguide cavity 12 and the ET junction waveguide cavity 11 is a half-size rectangular waveguide port, and the end port of the equal-branch waveguide cavity 12 is connected to the half-waveguide-full-waveguide right-angle transformation structure 7.

[0036] Specifically, the power resistor load 10 is a gallium nitride power resistor load suitable for the Ku band and can withstand a power of 50W; the power resistor load 10 is welded in the groove of the lower box body 1 by gold-tin eutectic welding, and the end of the microstrip probe 13 and the power resistor load 10 are bonded and connected by a gold ribbon or multiple gold wires.

[0037] Furthermore, the half-waveguide-full-waveguide right-angle transformation structure 7 realizes the right-angle turn of the waveguide while realizing the transformation from the half-size waveguide to the full-size waveguide, and has the characteristics of small transformation size, small insertion loss, and excellent return loss. When the waveguide corner is inscribed 4.5mm laterally and 11.2mm longitudinally, the insertion loss and return loss indicators are optimal.

[0038] Furthermore, the shielding box is composed of a lower box body 1 and an upper box body 2 that are interlocked, the microstrip probe 13 and the power resistor load 10 are located in the lower box body 1, and a corresponding cavity structure is provided on the upper box body 2; the upper box body 2 is provided with a plurality of countersunk holes, and the lower box body 1 is provided with corresponding threaded holes; the upper box body 2 and the lower box body 1 are fixed by screws passing through the countersunk holes and the threaded holes to form a shielding box.

[0039] Furthermore, the synthesis port and the distribution port are both standard WR28 waveguide ports, and the size of the waveguide port is 15.799 mm×7.899 mm.

[0040] Figure 7-Figure 9 They are respectively the output port amplitude curve, phase curve and isolation curve of the utility model, Fig.10 It is a return loss curve of the input and output ports, where the combined port of the shielding box is port 1, and the three distribution ports on the lower side wall of the shielding box are port 2, port 3 and port 4 from right to left. It can be seen from the figure that within the Ku band (13.75GHz-14.5GHz), the amplitude difference of the three output ports of the utility model is within 0.1dB; the phase difference is within 3.1°; the isolation between port 2 and port 3 is better than 18dB, and the isolation between port 2 and port 4, port 3 and port 4 is better than 25dB; the return loss of port 1 and port 4 is better than 20dB, and the return loss of port 2 and port 3 is better than 18dB.

[0041] The conversion relationship between return loss (RL) and standing wave ratio (VSWR) is shown in formula (1).

[0042]

[0043] According to formula (1), a return loss of 25 dB corresponds to a standing wave ratio of 1.12, a return loss of 20 dB corresponds to a standing wave ratio of 1.22, and a return loss of 18 dB corresponds to a standing wave ratio of 1.29.

[0044] In summary, the utility model has the characteristics of simple structure, good amplitude and phase consistency, small insertion loss, good port standing wave and high isolation, and solves the problems of low isolation and poor standing wave ratio of the output port of the existing waveguide three-way power distributor / synthesizer.

[0045] The brief working principle of the utility model is as follows:

[0046] When used as a three-way power divider, the Ku-band signal is input from the combined port of the shielding box, and is subjected to unequal power distribution through the branch waveguide unequal power divider 3, and becomes two-way signals. The power of the straight-through output port signal is two-thirds of the total power of the input signal, and the power of the coupled output port signal is one-third of the total power of the input signal, and the phase difference between the two signals is 90°; the output signal of the straight-through output port passes through the "L"-shaped waveguide 4, the coplanar magic T divider 6 and the half-waveguide-full-waveguide right-angle conversion structure 7 in sequence, and is branched into two-way signals of equal amplitude and phase, and the power of each signal is one-third of the total power, and is output from the lower distribution port of the shielding box respectively; the output signal of the coupled output port is output from the lower distribution port of the shielding box through the "J"-shaped waveguide 5, and the phase of the signal of the distribution port of the shielding box is consistent with that of the other two distribution ports of the shielding box by adjusting the length of the "J"-shaped waveguide 5, and the power of the signal of the distribution port is also one-third of the total power of the input signal. Therefore, when the utility model is used as a three-way power distributor, the signal is input from the combining port of the shielding box, and the three distribution ports on the lower side wall of the shielding box output three signals of equal amplitude and phase; conversely, when used as a three-way power synthesizer, the three signals of equal amplitude and phase are respectively input from the three distribution ports on the lower side wall of the shielding box, and one synthesized signal is obtained at the combining port of the shielding box.

[0047] Those skilled in the art will appreciate that the embodiments described are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to the embodiments described. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A Ku-band waveguide three-way power splitter synthesizer, comprising a shielding box, characterized in that: A synthesis port is arranged on the left side wall of the shielding box, and three distribution ports are arranged on the lower side wall; a branch waveguide unequal power divider, an L-shaped waveguide, an X-shaped waveguide, a coplanar magic T divider and a half-waveguide-full-waveguide right-angle conversion structure are arranged in the shielding box; The branch waveguide unequal power divider comprises a four-branch waveguide directional coupler, a waveguide-microstrip transition structure and a power resistor load; the synthesis port on the left wall of the shielding box is the input port of the branch waveguide unequal power divider; the upper right waveguide port of the branch waveguide unequal power divider is a straight-through output port, and the lower right waveguide port is a coupled output port; the lower left waveguide port is an isolation port, which is connected to the waveguide-microstrip transition structure and is bonded to the power resistor load through a gold ribbon or multiple gold wires; a four-slit coupling array is provided between the input port and the coupled output port; The left port of the L-shaped waveguide is connected to the straight-through output port of the branch waveguide unequal power divider, and the lower port of the L-shaped waveguide is connected to the synthesis port of the coplanar magic T divider; the corner of the L-shaped waveguide is provided with a 45° bevel to ensure that it has a good return loss; The upper port of the X-shaped waveguide is connected to the coupling output port of the branch waveguide unequal power divider; the lower port of the X-shaped waveguide is one of the three distribution ports of the shielding box, and is located at the leftmost of the three ports; The coplanar magic T divider comprises an ET junction waveguide cavity, two equal-branch waveguide cavities and a microstrip probe, one end of the microstrip probe is inserted into the ET junction waveguide cavity, and the other end is connected to a power resistor load; the connection between the equal-branch waveguide cavity and the ET junction waveguide cavity is a half-size rectangular waveguide port, and the end port of the equal-branch waveguide cavity is connected to a half-waveguide-full-waveguide right-angle transformation structure.

2. A Ku-band waveguide three-way power splitter synthesizer according to claim 1, characterized in that: The power resistor load is a gallium nitride power resistor load suitable for the Ku band and can withstand a power of 50W; the power resistor load is welded in the groove of the lower box body of the shielding box through gold-tin eutectic welding, and the end of the microstrip probe and the power resistor load are bonded and connected by a gold ribbon or multiple gold wires.

3. The Ku-band waveguide three-way power splitter synthesizer according to claim 1, characterized in that: The waveguide-microstrip transition structure adopts an E-plane probe transition form, and the central axis of the microstrip probe is one quarter of a wavelength away from the end of the waveguide cavity.

4. The Ku-band waveguide three-way power splitter synthesizer according to claim 1, characterized in that: The shielding box consists of a lower box body and an upper box body that are interlocked. The microstrip probe and the power resistor load are located in the lower box body, and a corresponding cavity structure is provided on the upper box body. The upper box body is provided with a plurality of countersunk holes, and the lower box body is provided with corresponding threaded holes. The upper box body and the lower box body are fixed by screws passing through the countersunk holes and the threaded holes to form a shielding box.

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