JP2017076881A - Power combiner/distributor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform combination/distribution normally and well, while preventing occurrence of abnormal mode on a radial track, even when the interval of branch is increased.SOLUTION: A power combiner/distributor for combining and distributing microwave power includes a radial track 5 of radius R, and N ridge waveguides 8 connected onto the circumference of this radial track 5 at equal intervals. Assuming that the wavelength of microwave is λ at a position of radius R on the radial track 5, setting is made to satisfy a relation R<(N/4π)λ. More specifically, interval of adjoining branches is set smaller than one half of the wavelength. Furthermore, a transformer 9 is provided at a part where the ridge of the ridge waveguide 8 is extended to the radial track side, for impedance matching of the radial track and ridge waveguide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power combiner / distributor, and more particularly, to a configuration of a power combiner / distributor that includes a radial line and branches microwave power into a plurality or combines a plurality of powers.

  FIG. 5 shows a configuration of a 20 combiner / distributor which is a conventional power combiner / distributor. In FIG. 5, 1a is a central coaxial terminal, and 1b is a periphery provided at equal intervals on the circumference. Coaxial terminals, 2a and 2b are conversion elements, 4a is a top plate, 4b is a bottom plate, 4c is a side plate, and 5 is a radial line. In this example, the central coaxial terminal 1a and the 20 peripheral coaxial terminals 1b are coupled by the radial line 5, and can be combined and branched. The radial line length is adjusted according to the desired outer shape of the synthesizer / distributor.

JP-A-10-270915

By the way, when a larger size circuit such as another combiner / distributor or isolator is attached to each branch of the power combiner / distributor, it is necessary to widen the interval between the branches (peripheral coaxial terminals 1b) accordingly. However, in this case, the radial line 5 has a larger diameter R ₄ (FIG. 5), an abnormal mode occurs in the radial line 5, and power combining / distribution may not be performed as expected. It was.

As a result of examining the abnormal mode, it has been found that the abnormal mode is caused by the density of the electric field strength in the circumferential direction at the branch portion of the radial line 5.
That is, for example, in the case of a distributor that is N-branched using the radial line 5, the microwaves fed from the central part of the disk-shaped radial line spread uniformly in the radial direction and are distributed to the branched parts arranged at equal intervals. It reaches with phase and equal amplitude and is divided into N parts.

  However, in an actual distributor, the feeding position or branching position is slightly deviated from the ideal position due to the accuracy of machining, etc., and this deviation also slightly causes microwaves that should spread uniformly in a concentric manner in the radial direction. This will cause an abnormal electromagnetic field. At this time, when the interval between the branch terminals (peripheral coaxial terminal 1b) is longer than a half wavelength, a mode in which the electromagnetic field with a half wavelength is densely formed in the circumferential direction between the branch terminals occurs. In some cases, the operation of the distributor is abnormal. In the case of a synthesizer, the same abnormal mode occurs only when the transmission direction of the microwave is reversed.

  The present invention has been made in view of the above problems, and the object thereof is to perform normal and satisfactory synthesis and distribution without causing an abnormal mode in the radial line even when the branch interval is increased. It is to provide a power combiner / distributor.

In order to achieve the above object, the invention of claim 1 is a power combiner / distributor for combining or distributing microwave power, which is connected to a radial line having a radius R and a circumference of the radial line. N ridge waveguides satisfying the relationship of R <(N / 4π) λ where λ is the wavelength of the microwave at the radius R of the radial line.
According to the invention of claim 2, impedance matching between the radial line and the ridge waveguide is achieved by extending the ridge portion of the ridge waveguide toward the radial line and using the extension as a transformer. It is characterized by that.

  According to the above configuration, the ridge waveguide is coupled to the radial line, and the radius R of the radial line is smaller than (n / 4π) λ, that is, the interval between adjacent branches is less than a half wavelength. Since it is made smaller, an abnormal mode due to the density of electric field strength in the circumferential direction does not occur at the branch portion, and uniform distribution / combination can be performed.

  In addition, the ridge portion of the ridge waveguide is extended to the radial line side with an appropriate dimension, and this extended portion is a stepped shape having a length of approximately a quarter wavelength or a taper having a length of a half wavelength. By providing a transformer as a shape or the like, impedance matching can be achieved at the connection portion between the radial line and the ridge waveguide, and mismatching at this portion can be eliminated.

According to the present invention, even when the branch interval is increased and the machining accuracy of the feeding position and the branch position is slightly deviated from the ideal position, an abnormal mode does not occur in the radial line, and synthesis / distribution is performed. It becomes possible to perform normally and satisfactorily.
In a conventional synthesizer / distributor, when a relatively large circuit is connected to a branch portion (branch terminal), it is common to connect a coaxial line to a radial line. It is difficult to process the length of the line uniformly, and there is a disadvantage that the composition / distribution tends to vary, and the passage loss of the coaxial line is larger than that of the waveguide or ridge waveguide. In the case of use with electric power, there was a problem such as heat generation. Therefore, the present invention solves the above problem by connecting a ridge waveguide to a radial line so that the interval between the branch terminals can be easily increased. Note that the ridge waveguide has a larger cutoff wavelength than a normal rectangular waveguide, and allows microwaves to pass well even when the spacing between the branch terminals is smaller than a half wavelength. Is possible.

  Also, by providing a transformer in which the ridge portion of the ridge waveguide is extended to the radial line side, impedance matching between the ridge waveguide and the radial line is well achieved, and good synthesis characteristics and distribution characteristics are obtained. It becomes possible.

It is a perspective view which shows a part structure (part except a top plate) of the peripheral part from the center part of the electric power combiner / distributor of the Example of this invention. It is a perspective view which shows the whole structure (state except the top plate of the right half) of the electric power combiner / distributor of an Example. It is a graph which shows the reflection characteristic of the electric power combiner / distributor of an Example. It is a graph which shows the reflection characteristic of the electric power combiner / distributor of a prior art example. The structure of the conventional electric power combiner / distributor is shown, FIG. (A) is a partial cross-sectional view, and FIG. (B) is an enlarged view of the cross-sectional portion.

  FIG. 1 and FIG. 2 show the configuration of the power combiner / distributor of the embodiment. The embodiment targets the 7.2 GHz band and has 20 branches around the disc body. . In each figure, 1a is a central coaxial terminal (coaxial line) disposed at the center of the disk, 1b is a peripheral coaxial terminal (coaxial line) disposed around the disk, and 2a is a conversion element for the central coaxial terminal 1a. (Conical line) 2b is a conversion element for the peripheral coaxial terminal 1b, 7a is a top plate of the housing, 7b is a bottom plate, 7c is a side plate, and 5 is a radial line of radius R1.

  In the embodiment, 20 (N) ridge waveguides 8 are connected at equal intervals (or a predetermined interval) on the circumference of the radial line 5 having the radius R 1, and the outer sides of the respective ridge waveguides 8. The peripheral coaxial terminal 1b is provided at the end, and the central coaxial terminal 1a is disposed at the center of the disc body, and the peripheral coaxial terminal 1b is disposed at the periphery. The coaxial line (1a, 1b) has a characteristic impedance of 50Ω and is not shown, but a connector for connecting another cable is attached to this end. The conversion element (conical line) 2a is a conversion circuit for impedance matching between the central coaxial line (1a) and the radial line 5, and the conversion element 2b is an impedance between the peripheral coaxial line (1b) and the ridge waveguide 8. This is a conversion circuit for performing matching.

  In the embodiment, the radius R1 (FIG. 1) of the radial line 5 is set to 60 mm, and the radius R1 is set to be smaller than (N / 4π) λ. That is, the wavelength of the microwave 7.2 GHz at the position of the radius R1 of the radial line 5 is 41.7 mm and the number of branches N is 20, so that (20 / 4π) × 41.7≈66.4 mm. A value that satisfies the expression. This means that the interval 2πR / N between adjacent branches is smaller than a half wavelength, which prevents the occurrence of a higher-order abnormal mode in the circumferential direction at the R1 position. Power combining and distribution is performed.

The combination and distribution of power will be described in detail with reference to FIGS.
In this embodiment, the distance R2 between the central coaxial terminal 1a and the peripheral coaxial terminal 1b is 115 mm. However, in the conventional power combiner / distributor of FIG. When the interval R4 of 1b is set to 115 mm, depending on the assembling accuracy at the time of assembling, as shown in FIG. 4, the reflection characteristic accompanied with an abnormal mode is obtained in the vicinity of 7.4 GHz or 8.45 GHz. This abnormal mode is the above-described higher-order mode having electromagnetic field density in the circumferential direction, and the composition / distribution is disturbed. That is, the power transmission between the peripheral coaxial terminal 1b and the central coaxial terminal 1a, which are branches, deviates from the same amplitude and the same phase, resulting in deterioration of the power combining / distribution characteristics.

  On the other hand, in the embodiment, the assembly accuracy of the synthesizer / distributor is poor, and even if each branch is slightly deviated from the axially symmetric position, the excellent reflection characteristics shown in FIG. 3 are obtained and no abnormal mode occurs.

  In the embodiment, when the ridge waveguide 8 is connected to the radial line 5 at the radius R1 = 60 mm, the distance between the adjacent ridge waveguides 8 is 18.8 mm at the connection position, and the operating frequency is 7. It becomes smaller than a half wavelength of 2 GHz = 20.8 mm. For example, if a normal rectangular waveguide is connected instead of the ridge waveguide 8, the width of the rectangular waveguide becomes smaller than a half wavelength, and the 7.2 GHz microwave is cut off. And does not propagate. Therefore, in the power combiner / distributor of the present invention, by using the ridge waveguide 8, it is possible to design so as not to be cut off even when the interval between them is smaller than a half wavelength. . The width W (FIG. 1) of the ridge waveguide of the embodiment is about 13 mm.

  Further, in the embodiment, the ridge portion of the ridge waveguide 8 is extended to the radial line 5 side, and a transformer 9 is provided at the extended portion, and this transformer 9 has a quarter wavelength at the ridge portion. (1/4 wavelength transformer), and the impedance matching between the radial line 5 and the ridge waveguide 8 is performed. This quarter-wave transformer 9 is different from the normally-known quarter-wave transformer in that it has a structure in which a step is provided only in the ridge portion, and a structure in which a step is provided in the radial line 5 itself. Not done. That is, when the step shape is attached to the ridge portion as in the embodiment, the impedance adjustment can be performed in a wide band and the machining is easier than the case where the step shape is attached to the radial line 5 itself. . As the transformer 9, a ridge portion having a taper shape having a length of a half wavelength may be used.

  In the ridge waveguide 8 of the above-described embodiment, the example in which the ridge portion and the transformer 9 are provided on the bottom plate 7b side is shown, but in addition, the ridge portion and the transformer 9 are also provided on the top plate 7a side ( Double ridge).

1a ... central coaxial terminal, 1b ... peripheral coaxial terminal,
2a, 2b ... conversion elements,
4a, 7a ... top plate, 4b, 7b ... bottom plate,
4c, 7c ... side plate, 5 ... radial line,
8 ... ridge waveguide, 9 ... quarter wavelength transformer.

Claims (2)

A power combiner / distributor for combining or distributing microwave power,
A radial track of radius R,
N ridge waveguides connected on the circumference of the radial line,
If the wavelength of the microwave at the radius R of the radial line is λ,
R <(N / 4π) λ
Power combiner / distributor that satisfies the above relationship.   2. The impedance matching between the radial line and the ridge waveguide is achieved by extending a ridge portion of the ridge waveguide toward a radial line and using the extension as a transformer. The power combiner / distributor according to 1.

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