WO2022024318A1

WO2022024318A1 - Waveguide coupler

Info

Publication number: WO2022024318A1
Application number: PCT/JP2020/029314
Authority: WO
Inventors: 秀憲湯川; 毅大島; 裕之青山; 徹高橋
Original assignee: 三菱電機株式会社
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2022-02-03
Also published as: JP7128570B2; JPWO2022024318A1

Abstract

A waveguide coupler according to the present disclosure comprises first to third main waveguides (9, 10, 11) in which an overall twist angle is 0 degrees and a passing phase at a center frequency used is an odd multiple of 90 degrees; a fourth main waveguide (12) in which an overall twist angle is plus or minus 180 degrees and the passing phase is 180 degrees inverted with respect to the passing phase of the first to third main waveguides (9, 10, 11); and first to fourth input/output waveguides (1, 2, 3, 4) respectively connected to connection sections (13, 14, 15, 16) of the first to fourth main waveguides (9, 10, 11, 12) that are connected in a ring shape.

Description

Waveguide coupler

This disclosure relates to a waveguide coupler.

Generally, a rat race ring type waveguide coupler (hereinafter referred to as "rat race coupler") is known as a waveguide coupler capable of distributing a 180-degree phase difference. The rat race coupler is composed of an annular main line portion and four input / output lines. The annular main line portion is configured by connecting three {nλ / 4} length main lines and one {nλ / 4 + λ / 2} length main line in an annular shape. (Here, λ is the wavelength of the center frequency f0 used, and n is an odd number). The four input / output lines are connected to each of the four connection portions of the main line. The four input / output lines are provided with four ports (P1, P2, P3, and P4) at the ends opposite to the side connected to the main line side (for example, non-patented). 12 and 15 of Document 1.

When a high frequency with a wavelength of λ is input to one of the ports of the rat race coupler, the high frequency is equally distributed and output from two of the remaining three ports. Depending on how the input port is selected, the distributed high frequencies may be in-phase or 180-degree phase difference. Explaining with reference to FIG.

In the conventional rat race coupler, the length of the three main lines is an odd multiple of λ / 4, and the length of one main line is exactly λ / 2 (the length of the three main lines). It is longer by half the wavelength of the center frequency f0 used). Since the length of the main line is determined based on the wavelength λ of the used center frequency f0 in this way, when the input high frequency is the used center frequency f0, the high frequency reverses the circular main line portion clockwise. It is transmitted in a clockwise direction, and cancels or overlaps well at the output port. As a result, the high frequency of the used center frequency f0 can be distributed in phase or 180 degree phase difference.

However, when the input high frequency has a frequency f different from the center frequency f0 used, this high frequency does not cancel or overlap well at the output port. As a result, the distribution amplitude and distribution phase as designed cannot be obtained at a frequency f different from the center frequency f0 used. The conventional rat race coupler has a problem that the distribution amplitude and the distribution phase are determined depending on the relationship between the length of the main line and the wavelength of the input high frequency. An object of the present disclosure is to provide a waveguide coupler having a phase correction mechanism that does not depend on an input high frequency wavelength in order to solve this problem.

In order to solve the above problems, the waveguide coupler of the present disclosure has a twist angle of 0 degrees as a whole, and the passing phase at the center frequency used is an odd multiple of 90 degrees. And the fourth main waveguide section, whose overall twist angle is plus or minus 180 degrees and whose passing phase is 180 degrees inverted from the passing phase of the first to third main waveguide sections, is annular. The first to fourth input / output waveguides connected to the respective connection portions of the first to fourth main waveguides connected to the above are provided.

With the above configuration, even at a frequency f different from the center frequency f0 used, the fourth main waveguide section has a passing phase difference of 180 degrees from the first to third main waveguide sections. The same effect as increasing the length of one line by λ / 2 over the other main lines can be obtained. By this phase correction mechanism that does not depend on the input high frequency wavelength, it is possible to obtain a waveguide coupler having a wider frequency band than the conventional rat race coupler.

A perspective view for explaining the configuration of the waveguide coupler according to the first embodiment. A plan view for explaining the configuration of the waveguide coupler according to the first embodiment. Perspective view of the twisted waveguide according to the first embodiment Sectional drawing of the part indicated by arrow AA of FIG. Perspective view of the first to third

phase correction units

17, 18 and 19. Perspective view of the fourth phase correction unit 20 Perspective view of the calculation model of the conventional rat race coupler Top view of the computational model of a conventional rat race coupler Computational model for verifying the pass phase difference between the two main waveguides that form a conventional rat race coupler Simulation results of the pass phase difference between two types of main waveguides in a conventional rat race coupler Simulation results of pass and bond amplitude characteristics of conventional rat race couplers Simulation result of distribution amplitude difference of conventional rat race coupler Simulation result of distribution phase difference of conventional rat race coupler Part 1 Simulation result of distribution phase difference of conventional rat race coupler Part 2 Calculation model of waveguide coupler according to the first embodiment A computational model for verifying the pass phase difference between the two types of main waveguides that form the waveguide coupler according to the first embodiment. Simulation result of passing phase difference between two types of main waveguides of the waveguide coupler according to the first embodiment Simulation result of amplitude characteristics of passing and coupling of the waveguide coupler according to the first embodiment Simulation result of distribution amplitude difference of waveguide coupler according to the first embodiment

Simulation result 1 of the distribution phase difference of the waveguide coupler according to the first embodiment

Simulation result 2 of the distribution phase difference of the waveguide coupler according to the first embodiment An example in which the phase correction portions of the waveguide coupler according to the first embodiment are arranged in a nested manner. A perspective view for explaining the configuration of the waveguide coupler according to the second embodiment. A plan view for explaining the configuration of the waveguide coupler according to the second embodiment. Perspective view of the twisted waveguide constituting the waveguide coupler according to the second embodiment. A perspective view for explaining the configuration of the half-height waveguide coupler according to the second embodiment. A plan view for explaining the configuration of the half-height waveguide coupler according to the second embodiment. A perspective view for explaining the configuration of the waveguide coupler according to the third embodiment. A plan view for explaining the configuration of the waveguide coupler according to the third embodiment. Perspective view of the twisted waveguide according to the third embodiment Cross-sectional view of the portion indicated by the arrow BB in FIG. 24. A perspective view for explaining the configuration of the waveguide coupler according to the fourth embodiment of the present disclosure. A plan view for explaining the configuration of the waveguide coupler according to the fourth embodiment of the present disclosure.

Embodiment 1.
FIG. 1 is a perspective view for explaining a configuration of a waveguide coupler according to the first embodiment of the present disclosure. Unless otherwise specified thereafter, the waveguide shown in the figure represents the shape of the hollow portion of the waveguide. The waveguide coupler according to the first embodiment is composed of an annular main waveguide portion and four input / output waveguides. In the annular main waveguide section, the first main waveguide section 9, the second main waveguide section 10, the third main waveguide section 11, and the fourth main waveguide section 12 are connected in a ring shape. It is configured. The connection points of the main waveguide are the first connection 13, the second connection 14, the third connection 15, and the fourth connection 16, each of which is the first input / output waveguide. 1. The second input / output waveguide 2, the third input / output waveguide 3, and the fourth input / output waveguide 4 are radially connected. The four input / output waveguides have a first input / output terminal 5, a second input / output terminal 6, and a third input / output terminal at the ends opposite to the side connected to the main waveguide side, respectively. A terminal 7 and a fourth input / output terminal 8 are provided.

Further, FIG. 2 is a plan view for explaining the configuration of the waveguide coupler according to the first embodiment of the present disclosure. The first to fourth

main waveguide sections

9, 10, 11, and 12 have a first phase correction section 17, a second phase correction section 18, a third phase correction section 19, and a fourth phase correction, respectively. It has a unit 20. The first phase correction unit 17 is configured by connecting

twisted waveguides

21 and 22 in series. Similarly, the second phase correction unit 18, the third phase correction unit 19, and the fourth phase correction unit 20 include

twisted waveguides

23 and 24,

twisted waveguides

25 and 26, and twisted waveguides. 27 and 28 are connected in series, respectively.

FIG. 3A is a perspective view of the appearance of the twisted waveguides 21 to 28 according to the first embodiment of the present disclosure. FIG. 3B shows the hollow portion of the twisted waveguides 21 to 28 shown in FIG. 3A. FIG. 4 is a cross-sectional view of a portion indicated by arrows AA in FIG. The twisted waveguides 21 to 28 are configured by connecting two twisted input /

output waveguides

29 and 30 via a waveguide conversion unit 31. The waveguide conversion unit 31 is formed by cutting out two corners of a square waveguide. The square waveguide having two corners cut out may have the cross-sectional shape shown in FIG. 4A or FIG. 4B.

FIG. 5 is a perspective view of the first to third

phase correction units

17, 18, and 19. The first phase correction unit 17 has two twisted

waveguides

21 and 22 connected in series with a twist angle of plus or minus 90 degrees, and the total twist angle is 0 degrees. The second phase correction unit 18 and the third phase correction unit 19 are also configured in the same manner as the first phase correction unit 17, and the overall twist angle is 0 degrees. The first to third

main waveguide sections

9, 10 and 11 have first to third

phase correction sections

17, 18 and 19, respectively. Further, the first to third

main waveguide portions

9, 10 and 11 all have a length having a passing phase of 90 degrees at the used center frequency f0.

FIG. 6 is a perspective view of the fourth phase correction unit 20. The fourth phase correction unit 20 has two twisted

waveguides

27, 28 connected in series with a twist angle of plus or minus 90 degrees, and the total twist angle is plus or minus 180 degrees. Further, the fourth main waveguide section 12 having the fourth phase correction section 20 has the same length as the first to third

main waveguide sections

9, 10 and 11.

The operation of the waveguide coupler of the present disclosure can be explained as follows. A twisted waveguide having a twist angle of plus or minus 90 degrees is configured by mechanically twisting the waveguide, or as shown in FIG. 3, the directions of the twisted input /

output waveguides

29 and 30 are orthogonal to each other. It is conceivable to connect and configure in this way. The length and notch size of the waveguide conversion unit 31 are design parameters that contribute to the reflection characteristics. The arrows shown in FIGS. 5 and 6 indicate the direction of the electric field. In the first to third

phase correction units

17, 18 and 19 shown in FIG. 5, the directions of the electric fields at both ends are the same. On the other hand, in the fourth phase correction unit 20 shown in FIG. 6, the directions of the electric fields at both ends are opposite. Here, the phase correction units shown in FIGS. 5 and 6 have the same physical length for propagating high frequencies. Since the propagation distances are the same in this way, the passing phases produced by this distance are the same. That is, a phase difference of 180 degrees (minus 180 degrees) occurs between the phase correction unit shown in FIG. 5 and the phase correction unit shown in FIG. 6 regardless of the frequency f. Therefore, when the passing phase of the main waveguide section provided with the phase correction section shown in FIG. 5 is 90 degrees at a certain frequency f0, the passing phase of the main waveguide section provided with the phase correction section shown in FIG. 6 has the same frequency. At f0, it becomes 270 degrees (minus 90 degrees).

Therefore, the waveguide coupler according to the first embodiment of the present disclosure functions as a rat race coupler. Further, since the phase difference of 180 degrees between the three main waveguides and one main waveguide for functioning as a rat race coupler can be obtained regardless of the frequency f, the induction according to the first embodiment of the present disclosure. The waveguide coupler has a wider frequency band than the conventional rat race coupler.

The effect of the waveguide coupler of the present disclosure can be explained as follows using the electromagnetic field simulation result. FIG. 7 is a perspective view of a calculation model of a conventional rat race coupler, FIG. 8 is a plan view thereof, and FIG. 9 is a calculation model for verifying the passing phase difference between two types of main waveguides forming the conventional rat race coupler. Is. FIG. 10 shows the simulation results of the passing phase difference between the two types of main waveguides in the conventional rat race coupler. Although a passing phase difference of 180 degrees is obtained at the used center frequency f0, the difference deviates from 180 degrees as the frequency f moves away from the used center frequency f0.

FIGS. 11-1 to 11-4 show the simulation results of the frequency characteristics of the conventional rat race coupler. The horizontal axis represents the frequency {f / f0}, and is normalized by dividing the input high frequency frequency f by the used center frequency f0.

FIG. 11-1 shows plots S14, S32, S12 and S34. Plot S14 is the amplitude characteristic of the frequency transfer function from port4 to port1. Plot S32 is the amplitude characteristic of the frequency transfer function from port2 to port3. Similarly, plot S12 is the amplitude characteristic of each frequency transfer function from port 2 to port 1, and plot S34 is the amplitude characteristic of each frequency transfer function from port 4 to port 3. These plots will be referred to as "passing, coupling amplitude characteristics". As for the amplitude characteristics of passing and coupling, the amplitudes match only at the used center frequency f0, and the difference increases as the distance from the used center frequency f0 increases. Further, although not shown, the phase characteristics of passing and coupling are 180 degrees or 0 degrees only at the used center frequency f0, and the difference increases as the distance from the used center frequency f0 increases.

FIG. 11-2 shows plots S12-S32 and S14-S34. The plots S12-S32 are amplitude characteristics of a function obtained by subtracting the frequency transfer function represented by the plot S32 from the frequency transfer function represented by the plot S12. That is, the plots S12-S32 are amplitude characteristics of a signal obtained by subtracting the signal of port3 from the signal of port1 with respect to the signal distributed to port1 and port3 when a high frequency is input to port2. Similarly, plots S14 to S34 are amplitude characteristics of a signal obtained by subtracting the signal of port3 from the signal of port1 with respect to the signal distributed to port1 and port3 when a high frequency is input to port4. These plots will be referred to as the "distribution amplitude difference".

FIGS. 11-3 and 11-4 show plots S12-S32 and plots S14-S34, respectively. The plots S12-S32 in FIG. 11-3 represent the phase characteristics of the signal obtained by subtracting the signal of port3 from the signal of port1 with respect to the signal distributed to port1 and port3 when a high frequency is input to port2. .. Similarly, plots S14-S34 in FIG. 11-4 show the phase of the signal obtained by subtracting the signal of port3 from the signal of port1 with respect to the signal distributed between port1 and port3 when a high frequency is input to port4. Represents a characteristic. These plots will be referred to as "distributed phase differences".

As shown in FIGS. 11-2 to 4, the distribution amplitude difference and the distribution phase difference of the conventional rat race coupler are as designed at the center frequency of use f0, but deviate from the design values as the distance from the center frequency of use f0 increases. .. For example, when the distribution amplitude difference is allowed from 0 to 0.2 [dB], the frequency band suitable for use is {f / f0} of about 0.99 to 1.01.

On the other hand, FIGS. 12 to 15-1 to 15-4 show a simulation of the frequency characteristics of the waveguide coupler according to the first embodiment of the present disclosure. FIG. 12 is a calculation model of the waveguide coupler according to the first embodiment, and FIG. 13 is a calculation model for verifying the passing phase difference between the two types of main waveguide portions forming the waveguide coupler according to the first embodiment. be. FIG. 14 is a simulation result of the passing phase difference between the two types of main waveguides of the waveguide coupler according to the first embodiment of the present disclosure. It can be seen that a passing phase difference of 180 degrees is obtained regardless of the frequency f. Further, FIG. 15 is a simulation result of the frequency characteristics of the waveguide coupler according to the first embodiment of the present disclosure. FIG. 15-1 is a diagram showing the passage and coupling amplitude characteristics. FIG. 15-2 is a diagram showing the distribution amplitude difference. 15-3 and 15-4 show plots S12-S32 and plots S14-S34, respectively, and are diagrams of distribution phase differences. It can be seen that the frequency dependence of the distribution amplitude difference in FIG. 15-2 and the distribution phase difference in FIGS. 15-3 and 15-4 is small. When the distribution amplitude difference is allowed from 0 to 0.2 [dB] as in the conventional rat race coupler, the frequency band suitable for using the waveguide coupler according to the first embodiment of the present disclosure is {f /. f0} is wider than 0.90 to 1.03.

As described above, the waveguide coupler according to the first embodiment has the configuration of the present disclosure, so that even at a frequency f different from the center frequency f0 used, only one main line length is used for another main line. The same effect as making it longer by λ / 2 can be obtained. By this phase correction mechanism that does not depend on the input high frequency wavelength, it is possible to obtain a waveguide coupler having a wider frequency band than the conventional rat race coupler.

Further, the physical lengths of the first, second, third, and fourth

main waveguide sections

9, 10, 11, and 12 are exactly the same, and a square-shaped arrangement is possible. Therefore, there is also an effect that the size is smaller than that of the conventional rat race ring having a different physical length of the main line.

Further, as shown in FIG. 16, the position of the phase correction unit does not have to be in the center of the main waveguide, and may be nested. In this case as well, the relationship between the passing phases of each main waveguide does not change, so that the same effect can be obtained. Further, since the positions of the phase correction units are separated from each other, the wall of the waveguide can be made thicker, which has the effect of improving manufacturability and strength.

Although the case where the passing phase of the first, second, and third

main waveguide portions

9, 10 and 11 is 90 degrees is shown here, it may be an odd multiple of 90 degrees.

Embodiment 2.
17 is a perspective view for explaining the configuration of the waveguide coupler according to the second embodiment of the present disclosure, FIG. 18 is a plan view thereof, and FIG. 19 is a twist constituting the waveguide coupler according to the second embodiment. It is a perspective view of the waveguides 121 to 128 (representatively 121). As shown in FIGS. 17, 18 and 19, the twisted waveguides 121 to 128 according to the second embodiment are provided with R (roundness) along the edge portion of the wide wall surface dimension (so-called A dimension). There is.

The same effect as that of the first embodiment can be obtained by the second embodiment.

Further, since the twisted waveguides 121 to 128 according to the second embodiment are provided with an R at the edge portion, the space between the twisted waveguide 126 and the twisted waveguide 127 is widened. The wall of the waveguide can be made thicker (the part circled by the dotted line in FIG. 18). This also has the effect of improving ease of manufacture and strength.

Further, the input / output waveguides 101B to 104B shown in FIGS. 20 and 21 are not standard but half-height (B dimension is half of the standard). Since the B dimension of the main waveguides 109B to 112B is also reduced, the twisted waveguides 121B and the twisted waveguides 122B are closer to each other than when the input / output waveguides 101B to 104B are formed of standard waveguides. It will be. Therefore, the effect of providing R at the edge of the waveguide constituting the waveguide coupler is further enhanced.

Although the case where R is provided at the edge of the waveguide is shown here, the waveguide may be provided with C (cut) at the edge.

Embodiment 3.
FIG. 22 is a perspective view for explaining the configuration of the waveguide coupler according to the third embodiment of the present disclosure, and FIG. 23 is a plan view thereof. The twisted waveguides 221 to 228 according to the third embodiment have an arc-shaped waveguide conversion unit 231. FIG. 24 is a perspective view of the twisted waveguides 221 to 228 (representatively 221) according to the third embodiment, and FIG. 25 is a cross-sectional view of a portion indicated by an arrow BB in FIG. 24. The square waveguide according to the third embodiment may have the cross-sectional shape of FIG. 25A or FIG. 25B.

Since the electric field is concentrated in the central part of the waveguide conversion unit 231 of the twisted waveguides 221 to 228, the characteristics do not change regardless of whether the shape is arcuate or square. Therefore, the waveguide coupler according to the third embodiment has the same effect as the waveguide coupler according to the first embodiment.

Further, since the waveguide return portion 231 of the twisted waveguides 221 to 228 has an arc shape, the wall of the waveguide should be thickened by widening the space between the locations where the twisted waveguides 221 to 228 are close to each other. It also has the effect of improving ease of manufacture and strength.

Further, the waveguide twists 221 to 228 according to the third embodiment may be provided with R or C (cut) along the edge portion.

Embodiment 4.
FIG. 26 is a perspective view for explaining the configuration of the waveguide coupler according to the fourth embodiment of the present disclosure, and FIG. 27 is a plan view thereof. In the waveguide coupler according to the fourth embodiment, the main waveguide section is smoothly connected instead of an acute angle at the connection sections 313 to 316 between the main waveguide sections 309 to 312 and the input / output waveguide sections 301 to 304. There is.

The waveguide coupler according to the fourth embodiment has the same effect as the waveguide coupler according to the first embodiment.

Further, the waveguide coupler according to the fourth embodiment has an effect that good reflection characteristics can be easily obtained because the main waveguide portion is smoothly connected at the connection portions 313 to 316 instead of having an acute angle.

1, 1B, 101, 101B, 301 1st input / output waveguide 2, 2B, 102, 102B, 302 2nd input / output waveguide 3, 3B, 103, 103B, 303 3rd input / output Waveguides 4, 4B, 104, 104B, 304 4th input / output waveguides 5, 5B 1st input / output terminal, 6, 6B 2nd input / output terminal, 7, 7B 3rd input / output Terminals, 8, 8B, 4th input / output terminal, 9, 9B, 109, 109B, 209, 309, 1st main waveguide section, 10, 10B, 110, 110B, 210, 310, 2nd main waveguide section, 11, 11B, 111, 111B, 211, 311 Third main waveguide section, 12, 12B, 112, 112B, 212, 312 Fourth main waveguide section, 13, 313 First connection section, 14, 314 2nd connection, 15, 315, 3rd connection, 16, 316, 4th connection, 17 1st phase correction, 18 2nd phase correction, 19 3rd phase correction, 20th Phase correction unit of 4, 21 to 28, 121 to 128, 121B to 128B, 221 to 228 twisted waveguide, 29, 30, 129, 130, 229, 230 twisted input / output waveguide, 31, 131, 231 conduction Waveguide converter, f frequency, f0 center frequency used.

Claims

The first to third main waveguides, whose overall twist angle is 0 degrees and whose passing phase at the center frequency used is an odd multiple of 90 degrees,
A fourth main waveguide whose overall twist angle is plus or minus 180 degrees and whose passing phase is 180 degrees inverted from the passing phase of the first to third main waveguides.
The first to fourth input / output waveguides connected to the respective connecting portions of the first to fourth main waveguides connected in a ring shape, and
A waveguide coupler characterized by being equipped with.
The waveguide coupler according to claim 1, wherein the main waveguide section has two twisted waveguides connected in series and having a twist angle of plus or minus 90 degrees.
The waveguide coupler according to claim 2, wherein the twisted waveguide has a roundness along the edge portion on the wide wall surface side of the waveguide conversion unit.
The waveguide coupler according to claim 2, wherein the twisted waveguide is chamfered along an edge portion on the wide wall surface side of the waveguide conversion unit.
The waveguide coupler according to any one of claims 2 to 4, wherein the twisted waveguide has an arcuate edge on the narrow wall surface side of the waveguide conversion unit.
Claims 2 to 4, wherein the first to fourth main waveguides and the first to fourth input / output waveguides are connected at an acute angle at each of the connecting portions. The waveguide coupler according to any one of the above.
Claims 2 to 4, wherein the first to fourth main waveguides and the first to fourth input / output waveguides are smoothly connected at each connection. The waveguide coupler according to any one of the above.