WO2017113836A1 - Radial synthesizer of multiple high-isolation ultra-wideband waveguides - Google Patents

Abstract

A radial synthesizer of multiple high-isolation ultra-wideband waveguides comprises a base (1) and an upper cover (2). The base (1) comprises: trapezoidal platforms (12), the trapezoidal platforms (12) being distributed symmetrically around the edge of the base (1) and all having the same shape; wedges (17), each wedge (17) being located on a side of the respective trapezoidal platform (12) close to the center of the base (1), a tip of each wedge (17) pointing to the center of the base (1), and all of the wedges (17) having the same shape; isolation plates (13), disposed at the tips of the wedges (17) and all having the same shape; waveguide slots (11), each waveguide slot (11) being formed by a pair of adjacent combinations composed of the trapezoidal platform (12), the wedge (17) and the isolation plate (13); and a coaxial probe (14), located at the center of the base (1). The radial synthesizer of multiple high-isolation ultra-wideband waveguides is advantageous in simple processing, high-efficiency synthesis and wide operation bandwidth, therefore having very high value of engineering application.

Description

Multi-channel high isolation ultra-wideband waveguide radial synthesizer Technical field

The invention belongs to the technical field of radio frequency power amplifiers, and in particular relates to a multi-channel high isolation ultra-wideband waveguide radial synthesizer.

Background technique

Waveguide (WAVEGUIDE) is used to orient the structure that guides electromagnetic waves. Common waveguide structures mainly include parallel double wires, coaxial lines, parallel slab waveguides, rectangular waveguides, circular waveguides, microstrip lines, slab dielectric optical waveguides, and optical fibers. From the perspective of guiding electromagnetic waves, they can be divided into inner and outer regions, and electromagnetic waves are restricted to propagate in the inner region (requires the principle of lateral resonance to be satisfied in the waveguide cross section). Generally, a waveguide refers to a hollow metal waveguide and a surface wave waveguide of various shapes. The former completely confines the transmitted electromagnetic wave to a metal tube, which is also called a closed waveguide; the latter confines the guided electromagnetic wave around the waveguide structure, also called Open the waveguide.

High frequency, high power and miniaturization are the goals pursued by current solid-state microwave devices. High-frequency devices enable large bandwidth and information capacity; high-power devices extend the range of radiation; miniaturization enables microwave devices to be used in portable devices and satellite communications. However, high frequency and high power are a pair of contradictions. As the frequency increases, the device size will shrink, resulting in a significant drop in power capacity. In order to achieve high power in the high frequency range, multiple solid state microwave devices are often combined using power combining techniques, which is easier to implement and much less expensive than using a single high power device. With the increase of frequency, the current dominant planar power synthesis technology will not meet the needs, and space power synthesis technology has become a rapidly developing direction. When the operating frequency is as high as the millimeter wave band, the appearance of the high-order mode makes the design of the ordinary microstrip line complicated, and the power synthesis is generally realized by the waveguide.

The technique of using multiple antenna elements to transmit electromagnetic waves with the same frequency and phase conforming to a specific relationship so as to be superimposed and combined in a spatial propagation process, thereby forming an electromagnetic beam in a certain direction becomes a space power synthesis technique. Due to the large microstrip loss in the millimeter wave band and the low loss of the waveguide, various forms of synthesis are performed using waveguides. In the application of millimeter wave multiplexing, there are mainly binary tree synthesis and chain synthesis forms composed of 3dB bridges. Although using a 3dB bridge The binary synthesis is slightly more efficient than the multi-level chain synthesis in the same number of stages, but the tree synthesis requires a large number of 3dB bridges, which makes the whole structure become larger and larger with the increase of the synthesis order. The difficulty of implementation and the increase will be increased, so the 3dB bridge in the millimeter wave band is more suitable for one-two synthesis. The multi-stage chain synthesis is more efficient than the 3dB bridge tree synthesis as the number of stages increases. In order to obtain the maximum synthesis efficiency, the phase and amplitude of the chain synthesis must meet different conditions in each link, which makes the coupling degree of each branch different, which makes the coupled probe of multi-stage chain synthesis difficult. Processing is complicated and a matching diaphragm is also required.

It can be seen that the prior art space power combiner has the disadvantages of high loss, narrow bandwidth, and complicated processing.

Summary of the invention

The technical problem to be solved by the present invention is to propose a multi-path waveguide radial synthesizer with low loss, wide bandwidth and simple processing.

The technical solution proposed by the present invention to solve the above technical problem is: a multi-channel high isolation ultra-wideband waveguide radial synthesizer comprising a chassis and an upper cover, the chassis comprising:

a trapezoidal table, each of which is symmetrically distributed on the edge of the chassis, and each of the trapezoidal tables has the same shape;

a tip end, each of the tips is located at an end of each of the trapezoidal stages near the center of the chassis, the tip end of the tip is directed toward the center of the chassis, and each of the tips is identical in shape;

a separator, the separator being disposed at a tip end of the tip, and each of the separators having the same shape;

a waveguide groove, a combination of an adjacent pair of the trapezoidal table, the tip of the tip, and the spacer plate encloses the waveguide groove;

A coaxial probe is located at a substantially center of the chassis.

The multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further wherein a center of the upper cover is provided with a through hole for the top end of the coaxial probe to protrude.

a multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further wherein the same The shaft probe is composed of a first cylindrical boss, a second cylindrical boss laminated on the top of the first cylindrical boss, and an inner conductor vertically connected to the center of the top surface of the second cylindrical boss The needle is configured such that the axis lines of the first stud bump and the second stud boss coincide.

The multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further, the inner conductor probe is made of copper.

The multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further, the top surface of the second stud boss is provided with a blind hole, and the bottom end of the inner conductor probe is soldered or passed through a conductive glue Connected in the blind hole.

The multi-channel high-isolation ultra-wideband waveguide radial synthesizer as described above, further, each of the trapezoidal table and the upper cover are provided with screw connection holes corresponding to positions, and the chassis and the upper cover are combined Secured by screws.

The multi-channel high-isolation ultra-wideband waveguide radial synthesizer as described above, further, the multi-path waveguide is, for example, an 8-way, 16-way even-numbered path.

In the multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further, the center of the top surface of the upper cover is recessed to form a circular groove.

In the multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further, the inner surface of the chassis and/or the inner surface of the upper cover may be plated with silver to reduce power loss.

a multi-channel high isolation ultra-wideband waveguide radial synthesizer as described above, further, the chassis and the upper cover are both even-numbered disc-shaped bodies, the number of sides of the disc and the waveguide groove The number of routes is the same.

The beneficial effects of the invention are:

The multi-channel high isolation ultra-wideband waveguide radial synthesizer proposed by the invention adopts a magnetic coupling method for coaxial probe design, and uses a rectangular waveguide transform method to widen the working bandwidth. The multi-channel high isolation ultra-wideband waveguide radial synthesizer proposed by the invention has the characteristics of simple processing, high synthesis efficiency and wide working bandwidth, and has high engineering application value. Through the simulation analysis, the radial waveguide power synthesis/distribution structure of the present invention has an return loss in the range of 25.6 GHz to 34.9 GHz. The consumption is less than -20dB, and the relative bandwidth is more than 30%. In addition, the multi-channel high isolation ultra-wideband waveguide radial synthesizer proposed by the invention also has high synthesis efficiency, and the transmission loss in the working bandwidth is about -9.06 dB, and the synthesis efficiency is considerable in a wide bandwidth. .

In addition, the multi-channel high isolation ultra-wideband waveguide radial synthesizer proposed by the invention has a sheet-shaped isolation plate, which increases the isolation of the radial ports, so that the mutual interaction between the radial ports does not occur, thereby enabling power synthesis. The effect is better.

DRAWINGS

The above and/or other aspects and advantages of the present invention will become more apparent from the detailed description of the appended claims.

1 is a schematic diagram of a prior art radial waveguide transmission;

2 is a schematic structural view of a multi-channel high isolation ultra-wideband waveguide radial synthesizer according to an embodiment of the present invention;

Figure 3 is a structural exploded view of the multi-channel high isolation ultra-wideband waveguide radial synthesizer of Figure 2;

4 is a schematic structural view of an upper cover according to an embodiment of the present invention;

Figure 5 is a schematic structural view of a chassis according to an embodiment of the present invention;

6 is a schematic structural view of a coaxial probe according to an embodiment of the present invention;

7 is a schematic diagram showing a waveguide transform structure of a multi-channel high isolation ultra-wideband waveguide radial synthesizer according to an embodiment of the present invention;

8 is a schematic diagram of a reflection coefficient of a multi-channel high isolation ultra-wideband waveguide radial synthesizer according to an embodiment of the present invention;

9 is a schematic diagram showing transmission coefficients of a multi-channel high isolation ultra-wideband waveguide radial synthesizer according to an embodiment of the present invention.

In the drawings, the list of parts represented by each label is as follows:

1. Chassis, 11, guide groove, 12, trapezoidal table, 13, isolation plate, 14, coaxial probe, 141, first cylindrical boss, 142, second cylindrical boss, 143, inner conductor Needle, 15, synthetic cavity, 16, screw connection hole, 17, tip;

2, upper cover, 21, circular groove, 22, through hole, 23, screw connection hole.

detailed description

Hereinafter, an embodiment of the multi-channel high isolation ultra-wideband waveguide radial synthesizer of the present invention will be described with reference to the accompanying drawings.

The embodiments described herein are illustrative of specific embodiments of the invention, and are intended to be illustrative of the embodiments of the invention. In addition to the implementations described herein, those skilled in the art will be able to devise other obvious technical solutions based on the disclosure of the present application and the specification, which includes any obvious use of the embodiments described herein. Replacement and modification of the technical solution.

The drawings of the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of the respective portions and their mutual relations. It is to be noted that, in order to facilitate the clarity of the structure of the components of the embodiments of the present invention, the drawings are not drawn to the same scale. The same reference numerals are used to denote the same parts.

Radial waveguide synthesis uses waveguide space power synthesis in spatial synthesis, which is a closed space power synthesis. In the high-end and millimeter-wave bands of the microwave band, it is difficult to place multiple amplifier chips due to the limitation of the cross-section size of the waveguide cavity, which limits the number of synthesized circuits, and the crowded space also causes difficulties in heat dissipation of high-power amplifiers. Therefore, the scale of spatial power synthesis in the waveguide is limited by the actual conditions of the project. In view of the advantages of solid-state amplifiers in space applications compared to traveling wave tube amplifiers, waveguide internal space power synthesis amplifiers were proposed as an alternative to the latter in the early days, but the efficiency of solid-state amplifier chips is generally low, resulting in high power. The waveguide internal space power synthesis amplifier is very difficult to apply. Still, it makes sense to apply this technology to achieve a small- and medium-power output solid-state power amplifier, especially if the monolithic MMIC chip or single tube does not meet the power requirements.

In power synthesis technology, synthesis efficiency is one of the most important indicators, and the inconsistency of amplitude and phase has a great influence on the synthesis efficiency. In order to minimize the loss in the synthesis process, attention must be paid to the phase and amplitude. A structurally symmetric power combiner can ideally maintain amplitude and phase uniformity. Due to the structural characteristics of the radial waveguide, it is structurally symmetrical when applied to power synthesis. It has the same path in power distribution and synthesis, and is easy to synthesize in phase. At the same time, the radial waveguide adopts a waveguide transmission line, which has small insertion loss and large power capacity. advantage.

Figure 1 shows a schematic diagram of the transmission of a prior art radial waveguide. The radial waveguide is paralleled by two upper and lower The circular metal plate is composed of a medium filled with a dielectric constant of ε and a magnetic permeability of μ, and the distance between the two plates is b. The electromagnetic wave propagates in the radial direction in the radial waveguide, and has a cylindrical isophase plane.

For the time-harmonic field, the wave function φ satisfies the Helmholtz equation:

Where k ² =ω ² με,

For the Laplacian operator.

Expand the above formula with the column coordinates as:

The general solution of the above formula is:

Where 0<r<+∞,

0 ≤ z ≤ b.

Substituting equation (2) into equation (1), the m-order Bessel equation can be obtained by using the separation variable method:

In the formula,

R, Φ, Z are r, respectively

And the function of z. Assume

The solution of the above equation is the m-order Bessel function B _m (k _r r).

For the TM (Transverse Magnetic) mode, in the cylindrical coordinate system, the magnetic field and electric field equations in the radial waveguide are:

Considering only the electromagnetic wave propagating in the radial direction, it can be taken as the Hankel function in the Bessel function.

Representing the inward movement,

Representing outward traveling waves, along

The direction is a circular symmetry structure, and the wave function form is:

The wave function satisfies the boundary condition at z=0 and z=b:

The resulting TM wave function expression is:

Where m, n = 0, 1, 2, ...;

When the distance between the upper and lower metal plates of the radial waveguide is b < λ/2, the lowest mode of internal wave transmission of the radial waveguide is the TM ₀₀ mode, which is called the radial waveguide main mode. From the above solution of the TM wave, the field distribution of the main mode TM ₀₀ mode of the radial waveguide is:

The TM ₀₀ mode electric field of the radial waveguide has only the z-direction component, and the electric field is the same on the circumference of the same radius; the magnetic field is only

To the component, the magnetic field is equal in magnitude on the circumference of the same radius, and the direction is tangential to the circumference; the radial waveguide surface has only a radial surface current. If the TM ₀₀ mode is based on the propagation direction, it is called TEM ^(r) mode, r is the radial direction of propagation, and there is no r-direction electric field component or r-direction magnetic component in the electromagnetic field, which is a cylindrical TEM mode. The electric field and magnetic field of the TM ₀₀ mode are both Z,

Irrelevant, just a function of radial distance. It can be seen that the physical structure and the field distribution of the radial waveguide are both symmetric in the radial direction, which is beneficial to ensure equal amplitude and in phase in power distribution and power synthesis.

2 to 5 are views showing the structure of a multi-channel high isolation ultra-wideband waveguide radial synthesizer according to an embodiment of the present invention. As shown in FIGS. 2 to 5, the multi-channel high isolation ultra-wideband waveguide radial synthesizer includes a chassis 1 and an upper cover 2.

Wherein the chassis 1 comprises:

Trapezoidal stages 12, each of which is symmetrically distributed at the edge of the chassis, and each of the trapezoidal stages 12 is identical in shape. Note that the long side of the trapezoidal table 12 is not a strictly straight line, but is formed by connecting two equal length segments. Each of the trapezoidal table and the upper cover is provided with screw connection holes 23 corresponding to positions, and the chassis and the upper cover are respectively fixed by screws. In addition, the opposite sides of each two adjacent trapezoidal stages 12 are parallel.

a tip end 17, each of the tips 17 being located at an end of each of the trapezoidal stages 12 near the center of the chassis 1, the tip end of the tip pointing toward the center of the chassis 1, and each of the tips 11 the same. In addition, the opposite sides of each two adjacent tips 17 are parallel.

a partitioning plate 13 disposed at a tip end of the cusp 17 and each of the The spacers 17 are identical in shape. In addition, the opposite sides of each two adjacent separators 13 are parallel.

The waveguide groove 11 is formed by a combination of a pair of the adjacent trapezoidal stages 12, the tips 17 and the spacers 13 forming the waveguides 11. The waveguide groove 11 is, for example, an 8-way or 16-way even-numbered path. In the embodiment of the present invention, the number of paths of the waveguide groove 11 is 16 ways.

A coaxial probe 14 is located at the center of the chassis 1.

A circular groove 21 is formed at the center of the top surface of the upper cover 2, and a through hole 22 for extending the top end of the coaxial probe 14 is disposed at the center thereof. Both the chassis 1 and the upper cover 2 are even-numbered disk-shaped bodies made of an aluminum alloy material, which in this embodiment are disk-shaped bodies of sixteen sides.

Further, in order to reduce the power loss of the multi-channel high isolation ultra-wideband waveguide radial synthesizer of the present invention during transmission, silver may be plated on the inner surface of the chassis and/or the inner surface of the upper cover to reduce power loss.

Figure 6 shows a probe of an embodiment of the invention. As shown in FIG. 6, the probe is composed of a first stud boss 141, a second stud boss 142 laminated on the top of the first stud boss 141, and a top vertically connected to the second stud boss 142. The inner conductor probe 143 at the center of the face is formed, and the axial lines of the first cylindrical boss 141 and the second cylindrical boss 142 are coincident. The top surface of the second stud bump 142 is provided with a blind hole, and the bottom end of the inner conductor probe 143 is soldered or connected in the blind hole through a conductive adhesive, and the inner conductor probe 143 can be made of copper. Or made of gold. The first stud boss 141 has a height h1 and the first stud boss has a radius r1. The height of the second stud boss 142 is h2, the radius of the second stud boss is r2, the height of the radial waveguide is 3.556 mm of the height of the standard BJ-320 rectangular waveguide, and the impedance is matched by the boss to 50 ohms, and the connection is The coaxial inner conductor probe has a diameter of φ = 0.3 mm and the outside can be directly connected to a K-type connector (SMA-K connector). When the ideal TEM wave is excited by the central coaxial probe, a large electromagnetic field change occurs when the TEM wave is transmitted to the junction of the radial waveguide and the rectangular waveguide. However, because of the overall symmetry of the radial synthesizer, the electromagnetic waves still have axisymmetric characteristics, which makes the energy allocated to each channel the same. Helps the entire distribution/synthesizer achieve lower losses.

This coupling probe is characterized by the ability to match using the most basic stepped boss impedance transformation. Since the K-type connector is externally connected at the synthesizing end, the diameter of the coaxial inner conductor probe 143 is φ=0.3 mm, and the position in the radial waveguide can be fixed by magnetic coupling to ensure that the inner conductor probe 143 is at the center. Therefore, the processing is simple and the synthesis efficiency is also guaranteed.

FIG. 7 is a schematic view showing the connection structure of a radial waveguide and a rectangular waveguide according to an embodiment of the present invention. As shown in FIG. 7, the connection structure is composed of a first-stage waveguide and a second-stage waveguide. As shown in Figure 5, The first-order waveguide is surrounded by two adjacent trapezoidal stages 12, the width of which is the width between the opposite sides of the adjacent two trapezoidal stages 12, and the length of which is the length of the opposite sides of the adjacent two trapezoidal stages 12, respectively The length and width of the first stage waveguide are set to a and b. The second stage waveguide is surrounded by two adjacent tips 17, the width of which is the width between the opposite sides of the adjacent two tips 17, the length of which is the length of the opposite sides of the adjacent two tips 17. The second stage waveguide uses a standard BJ320 waveguide with a width a1 of 3.556 mm. A tip end of the tip end 17 is connected to a separating plate 13 which leads to the synthesis chamber 15. The inside of the synthesis chamber is a radial waveguide with a radius r.

This structure can change the wavelength of electromagnetic waves that can be transmitted in a rectangular waveguide, and can transmit a longer wavelength band and a lower frequency electromagnetic wave band in a wide waveguide section. Appropriate adjustment of the width a and the length b can reduce the influence of the mode variation caused by the wide waveguide connecting the narrow waveguide. Adjusting the radius r of the radial waveguide enables the high-order mode and coaxial probe excitation generated by the connection of the radial waveguide and the rectangular waveguide. The resulting higher order modes do not interact with each other. Table 1 shows the list of parameters obtained after the optimization of the parameters a, b, r is completed.

Table 1 Optimized connection structure parameters

In Fig. 8, a reflection coefficient diagram of a connection structure of an embodiment of the present invention is shown. As can be seen from FIG. 8, the connection structure makes the bandwidth greatly widened. When the reflection loss is below -20 dB, the bandwidth reaches 9.26 GHz, covering 25.6 GHz - 34.9 GHz, and the bandwidth is also 6.37 GHz when the -30 dB or less is covered. 27.3GHz-33.6GHz. In addition, the Ka-band low-band also has a wide bandwidth, the relative bandwidth of more than 30%.

Figure 9 shows a transmission coefficient diagram of an embodiment of the present invention. It can be seen from FIG. 9 that the connection structure maintains a low transmission state in addition to a wide bandwidth. In the bandwidth range, the transmission coefficient of the synthesis port to each distribution port is about -9.06 dB on average. . According to the formula

It can be estimated that the synthesis efficiency in the 25.6 GHz - 34.9 GHz is over 95%, and the synthesis efficiency is higher in the 27.3 GHz - 33.6 GHz.

Through simulation analysis, the multi-channel high isolation ultra-wideband waveguide radial synthesizer/divider of the embodiment of the invention has a return loss of less than -20 dB and a relative bandwidth of more than 30% in the range of 25.6 GHz to 34.9 GHz. And it has a high synthesis efficiency, the transmission loss in the working bandwidth is about -9.06dB, and has considerable synthesis efficiency in a wide bandwidth.

The multi-channel high isolation ultra-wideband waveguide radial synthesizer/dispenser of the embodiment of the invention is processed and passively tested. It can be seen from the test results that the test curve is basically consistent with the simulation curve because of the processing assembly precision and the test error. The impact of the bandwidth in the high frequency band has been reduced, with a total return loss of less than -20 dB in the range of 25.7 GHz to 32.7 GHz and a relative bandwidth of 23%. The transmission loss from the synthesis port to each distribution port is also within -9.1dB to -9.5dB, and the synthesis efficiency is above 84%, which proves that the design proposed by the present invention is feasible. Due to the limitation of processing precision, the transmission loss of this structure is large. With the current domestic processing technology, there is still much room for improvement in the working performance of the structure.

In addition, the 16 isolation plates 13 designed in the embodiments of the present invention increase the isolation of the ports, so that mutual interference does not occur between the radial ports. In addition, the spacer 13 concentrates the energy flowing to the adjacent ports to the synthesizing port, thereby effectively increasing the power combining efficiency.

The technical features disclosed above are not limited to the combinations of the disclosed features and other features, and other combinations of the various technical features may be made by those skilled in the art to achieve the object of the present invention.

Claims (10)

1. A multi-channel high isolation ultra-wideband waveguide radial synthesizer comprising a chassis and an upper cover, wherein the chassis comprises:

   a trapezoidal table, each of which is symmetrically distributed on the edge of the chassis, and each of the trapezoidal tables has the same shape;

   a tip end, each of the tips is located at an end of each of the trapezoidal stages near the center of the chassis, the tip end of the tip is directed toward the center of the chassis, and each of the tips is identical in shape;

   a separator, the separator being disposed at a tip end of the tip, and each of the separators having the same shape;

   a waveguide groove, a combination of an adjacent pair of the trapezoidal table, the tip of the tip, and the spacer plate encloses the waveguide groove;

   A coaxial probe is located at a substantially center of the chassis.
2. A multi-channel high-isolation ultra-wideband waveguide radial synthesizer according to claim 1, wherein a center of said upper cover is provided with a through hole for extending the top end of said coaxial probe.
3. A multi-channel high isolation ultra-wideband waveguide radial synthesizer according to claim 1 wherein said coaxial probe is laminated on said top of said first stud boss by a first stud bump a second stud boss and an inner conductor probe vertically connected at a center of a top surface of the second stud boss, the axis lines of the first stud boss and the second stud boss Coincident.
4. A multi-channel high isolation ultra-wideband waveguide radial synthesizer according to claim 3, wherein said inner conductor probe is made of copper.
5. The multi-channel high-isolation ultra-wideband waveguide radial synthesizer according to claim 3, wherein a top surface of the second stud boss is provided with a blind hole, and a bottom end of the inner conductor probe is soldered Or it is connected to the blind hole through a conductive glue.
6. A multi-channel high isolation ultra-wideband waveguide radial synthesizer according to claim 1 Each of the trapezoidal table and the upper cover is provided with a screw connection hole corresponding to the position, and the chassis and the upper cover are respectively fixed by screws.
7. The multi-channel high-isolation ultra-wideband waveguide radial synthesizer according to claim 1, wherein the multipath waveguide is, for example, an 8-way or a 16-way even-numbered path.
8. The multi-channel high-isolation ultra-wideband waveguide radial synthesizer according to claim 1, wherein a center of the top surface of the upper cover is recessed to form a circular groove.
9. The multi-channel high isolation ultra-wideband waveguide radial synthesizer of claim 1 wherein silver is plated on the inner surface of the chassis and/or the inner surface of the upper cover to reduce power loss.
10. The multi-channel high-isolation ultra-wideband waveguide radial synthesizer according to claim 1, wherein the chassis and the upper cover are both even-numbered disc-shaped bodies, and the number of sides of the disc is the same as The number of paths of the waveguide is the same.

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