JP7129263B2 - converter - Google Patents

Description

The present invention primarily relates to a converter that converts and transmits signals between a waveguide and a circuit board.

Patent Literature 1 discloses a feeder converter that includes a waveguide, a termination block, and a planar line (circuit board). Waveguides and termination blocks are tubular members of rectangular cross-section. One axial end of the end block is open and the other end is closed. A planar line is sandwiched between the waveguide and the open portion of the termination block. A planar line includes a probe. This probe converts the transmission mode of the waveguide (TE ₁₀ mode) and the transmission mode of the planar line (TEM mode).

JP-A-10-126114

In a converter that converts a signal between a waveguide and a circuit board, it is preferable that the band capable of converting the signal with low loss is wide. However, Patent Document 1 does not describe a specific configuration for solving this type of problem.

The present invention has been made in view of the above circumstances, and its main object is to provide a converter capable of converting signals in a wide band between a waveguide and a circuit board.

Means and Effects for Solving Problems

The problems to be solved by the present invention are as described above. Next, the means for solving the problems and the effects thereof will be described.

According to the aspect of the present invention, a converter having the following configuration is provided. That is, the transducer comprises a rectangular waveguide and a circuit board. The rectangular waveguide has an internal space formed by a conductor, and a signal is transmitted through the internal space. The circuit board is connected to the rectangular waveguide, has a first surface and a second surface, and is arranged such that its thickness direction coincides with the signal transmission direction. The circuit board includes a first conversion section, a first surrounding conductor, a second conversion section, and a second surrounding conductor. The first converter is formed on the first surface of the circuit board and includes a conductor for converting a signal transmission mode. The first peripheral conductor is formed on the first surface of the circuit board and surrounds at least a portion of the first converting portion when the circuit board is viewed in the thickness direction. The second converter is formed on the second surface of the circuit board, is electrically connected to the first converter, and includes a conductor for converting a transmission mode of a signal. The second peripheral conductor is formed on the second surface of the circuit board and surrounds at least a portion of the second converting portion when the circuit board is viewed in the thickness direction.

FIG. 2 is an exploded perspective view of the converter of the first embodiment viewed from the rectangular waveguide side; FIG. 2 is an exploded perspective view of the converter of the first embodiment as seen from the termination pipe side; FIG. 4 is a plan view showing the spacing of the peripheral conductors of the circuit board and the inner dimensions of the rectangular waveguide in the first embodiment; 5 is a graph comparing the frequency characteristics of the X band between the conventional example and the first embodiment; The disassembled perspective view which looked at the converter of 2nd Embodiment from the rectangular waveguide side. The top view which shows the space|interval of the surrounding conductor of a circuit board, and the internal dimension of a rectangular waveguide in 2nd Embodiment. The disassembled perspective view which looked at the converter of 3rd Embodiment from the rectangular waveguide side. The disassembled perspective view which looked at the converter of 4th Embodiment from the rectangular waveguide side. The disassembled perspective view which looked at the converter of 5th Embodiment from the rectangular waveguide side. The disassembled perspective view which looked at the converter of 6th Embodiment from the rectangular waveguide side.

Embodiments of the present invention will now be described with reference to the drawings. First, the converter 1 of the first embodiment will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is an exploded perspective view of the transducer 1 viewed from the rectangular waveguide 10 side. FIG. 2 is an exploded perspective view of the converter 1 viewed from the terminal tube 20 side. FIG. 3 is a plan view showing the spacing of the peripheral conductors 32 of the circuit board 30 and the inner dimensions of the rectangular waveguide 10. As shown in FIG.

The converter 1 is arranged in a radar device, a communication device, or the like. The converter 1 has a structure for converting the transmission mode of a signal between a waveguide and a circuit board for transmission. For example, the converter ₁ converts the transmission mode from TE10 mode to TEM mode when a signal (high frequency signal) is transmitted from a waveguide to a circuit board. On the other hand, the converter 1 converts the transmission mode from TEM mode to TE ₁₀ mode when the signal is transmitted from the circuit board to the waveguide. As shown in FIG. 1, the transducer 1 comprises a rectangular waveguide 10, a termination tube 20 and a circuit board 30. As shown in FIG.

As shown in FIG. 3, the rectangular waveguide 10 is a waveguide in which flat conductors are arranged so that the internal space is rectangular when viewed in the signal transmission direction (the axial direction of the rectangular waveguide 10). It is a wave tube. In other words, the rectangular waveguide 10 has a rectangular cross-sectional shape taken along a plane perpendicular to the transmission direction. An opening 10a is formed at one end of the rectangular waveguide 10 in the transmission direction. In the following description, as shown in FIG. 3 and the like, the direction along the long side of the rectangle is called the long side direction, and the direction along the short side of the rectangle is called the short side direction. Also, the magnetic field generated in the rectangular waveguide 10 is parallel to the long side direction. The electric field generated in the rectangular waveguide 10 is parallel to the short side direction.

As shown in FIG. 1, the rectangular waveguide 10 has a first portion 11, a second portion 12 and a third portion 13. As shown in FIG. The first portion 11 includes a portion in which the opening 10a is formed. The second portion 12 is arranged downstream of the first portion 11 in the transmission direction. The third portion 13 is arranged downstream of the second portion 12 in the transmission direction. The first portion 11, the second portion 12, and the third portion 13 all have the same inner dimension in the long side direction. The inner dimension of the first portion 11 in the short side direction is shorter than the inner dimension of the third portion 13 in the short side direction. The inner dimension of the second portion 12 in the direction of the short side gradually changes. Specifically, the inner dimension of the second portion 12 in the short-side direction is the same as that of the first portion 11 at the end connected to the first portion 11, and the distance from the first portion 11 (circuit board 30) is the same as that of the first portion 11. It gradually becomes longer along the transmission direction and is the same as the third portion 13 at the end connected to the third portion 13 .

Similar to the rectangular waveguide 10, the terminating tube 20 is a waveguide in which flat conductors are arranged so that the internal space is rectangular when viewed in the signal transmission direction (the axial direction of the terminating tube 20). is. Although the details will be described later, the internal space of the termination pipe 20 is not limited to a rectangle. The termination tube 20 is provided to appropriately convert the transmission mode of the signal. An opening 20 a is formed at one axial end of the terminal tube 20 . The rectangular waveguide 10 and the termination tube 20 are connected so that the openings 10a and 20a are aligned. A closing portion 20b is formed at the other end of the terminal tube 20 . The closed portion 20b is a portion closed with a conductor. Specifically, the closing portion 20b is composed of a plate-like conductor arranged perpendicular to the axial direction.

The circuit board 30 has a configuration called a microstrip line, in which a plurality of conductor foils are arranged on part of the front and back surfaces of a plate-shaped dielectric 35 serving as a base. The circuit board 30 is sandwiched between the rectangular waveguide 10 and the terminating tube 20 so that the thickness direction of the circuit board 30 and the transmission direction of the rectangular waveguide 10 are the same. In the following description, the surface of the circuit board 30 facing the rectangular waveguide 10 is defined as the front surface, and the surface facing the termination pipe 20 is defined as the rear surface. As shown in FIG. 1, a linear conductor 31 and a peripheral conductor 32 are arranged on the surface of the circuit board 30 .

The linear conductor 31 has a transmission portion 31a and a conversion portion 31b. The transmission portion 31a is an elongated portion that transmits signals. In this embodiment, the longitudinal direction of the transmission portion 31a is the same as the short side direction. Further, the transmission part 31a reaches the internal space so as to intersect the long sides of the rectangular waveguide 10 and the termination tube 20 when viewed in the thickness direction of the circuit board 30 . A conversion section 31b is connected to the tip of the transmission section 31a. The converting portion 31b has a portion extending along the long side direction. The converter 31b is a part that converts the transmission mode of the signal. In this embodiment, the converting portion 31b is positioned at the center in the short side direction, but it may be positioned at the downstream side of the insertion from the center. The relationship between the position of the converter 31b and the band will be described later.

The peripheral conductor 32 surrounds the linear conductor 31 when viewed in the thickness direction of the circuit board 30 so that the dielectric 35 is positioned between the peripheral conductor 31 and the circuit board 30 as shown in FIG. are arranged as Specifically, the peripheral conductors 32 are arranged so as to form sides of a rectangle when viewed in the thickness direction of the circuit board 30 . Of the surrounding conductors 32, conductors corresponding to the short sides of the rectangle are called short-side conductors. The short-side conductors are arranged in pairs so as to face each other in the long-side direction. In the following description, these short-side conductors are denoted by reference numerals 32Sa and 32Sb. The short-side conductors 32Sa and 32Sb are arranged along the short sides of the rectangular waveguide 10. As shown in FIG. Among the surrounding conductors 32, conductors corresponding to long sides of the rectangle are called long-side conductors. The long-side conductors are arranged in pairs so as to face each other in the short-side direction. Also, one long-side conductor is configured separately so as not to interfere with the transmission section 31a. In the following description, these long-side conductors are denoted by reference numerals 32La and 32Lb. The long side conductors 32La and 32Lb are arranged along the long side of the rectangular waveguide 10. As shown in FIG.

Further, in the present embodiment, when viewed in the thickness direction of the circuit board 30, the position where the peripheral conductor 32 is arranged is the same as the position of the planar conductors of the rectangular waveguide 10 and the terminal tube 20. It is configured to include the following parts. Therefore, when viewed in the same direction, the position of the edge of the peripheral conductor 32 on the side of the internal space and the position of the conductor surface (inner surface) on the side of the internal space of the rectangular waveguide 10 and the terminal tube 20 are the same. Including the part that becomes. In addition, at the location where the transmission portion 31a is arranged, the surrounding conductor 32 is arranged along the transmission portion 31a with a predetermined distance from the transmission portion 31a. In addition, the position where the surrounding conductor 32 is arranged and the position of the planar conductors of the rectangular waveguide 10 and the termination tube 20 may be different from the position where the transmission part 31a is arranged.

As shown in FIG. 2, on the back surface of the circuit board 30, a back conversion portion 41b and a back peripheral conductor 42 are arranged. The back conversion portion 41b has the same shape as the conversion portion 31b. When viewed in the thickness direction of the circuit board 30, the back conversion portion 41b and the conversion portion 31b are arranged at the same position. Further, no conductive foil corresponding to the transmission section 31a is arranged on the back surface of the circuit board 30. As shown in FIG. Therefore, the rear peripheral conductor 42 is arranged so as to surround the periphery of the rear conversion portion 41b over 360°.

A through hole 33 is formed in the circuit board 30 at a location where the converting portion 31b and the back converting portion 41b are arranged. Since the through hole 33 has a conductive inner wall surface, it electrically connects the converting portion 31b and the back converting portion 41b. With this configuration, since the back surface conversion portion 41b contributes to the generation of an electric field in addition to the conversion portion 31b, the electric field energy generated between the circuit board 30 and the rectangular waveguide 10 and the termination tube 20 increases. Therefore, the band of the converter 1 can be widened.

Next, the relationship between the arrangement of the rectangular waveguide 10 and the surrounding conductor 32 and the band of the transducer 1 will be described with reference to FIGS. 3 and 4. FIG. FIG. 4 is a graph comparing the frequency characteristics of the X band between the conventional example and the first embodiment. Further, in the following description, in the short-side direction, the side of the transmission portion 31a (the tip side of the linear conductor 31) is called the back side, and the opposite side is called the front side.

In general, the inner dimension of the rectangular waveguide in the short side direction (that is, the distance between the planes parallel to the magnetic field) is determined according to the wavelength of the signal to be transmitted. In general, the inner dimension of the rectangular waveguide along the short side is about 1/3 of the wavelength of the signal to be transmitted (length L0 shown in FIG. 3). On the other hand, in the present embodiment, the inner dimension of the rectangular waveguide 10 in the short side direction is 1/4 or less of the wavelength of the signal to be transmitted (length L1 shown in FIG. 3). In addition, the distance between the inner ends of the peripheral conductor 32 in the short-side direction (the length L2 shown in FIG. 3, in other words, the distance in the short-side direction between the long-side conductor 32La and the long-side conductor 32Lb) is as described above. , it is the same as the inner dimension in the short side direction of the rectangular waveguide 10 (terminal tube 20).

In the graph of FIG. 4, a converter using a waveguide whose inner dimension in the short side direction is about 1/3 of the wavelength is taken as a conventional example, and the inner dimension in the short side direction is 1/4 or less of the wavelength. Taking the transducer 1 using the waveguide 10 as the first embodiment, the attenuation factor for each frequency in each X band is shown. When the allowable value of the attenuation factor is set as shown in FIG. 4, it can be seen that the band is basically very wide in the first embodiment as compared with the conventional example.

The reason why the band is widened in this embodiment is as follows. That is, the shorter the distance from the converting portion 31b to the peripheral conductor 32 on the far side (the inner surfaces of the rectangular waveguide 10 and the terminal tube 20 on the far side; the same shall apply hereinafter), the stronger the electric field. However, when the amount of insertion of the conversion portion 31b is increased and the conversion portion 31b is brought closer to the peripheral conductor 32 on the back side, an unnecessary portion that hinders signal conversion between the transmission portion 31a and the peripheral conductor 32 on the front side is formed. An electric field is generated. In this respect, by shortening the distance between the peripheral conductors 32 in the short side direction as in the present embodiment, the insertion amount of the conversion portion 31b can be reduced, and the distance from the conversion portion 31b to the peripheral conductor 32 on the far side can be shortened. can do. Therefore, the wide band shown in FIG. 4 can be realized.

Next, the converter 1 of the second embodiment will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is an exploded perspective view of the transducer 1 of the second embodiment viewed from the rectangular waveguide 10 side. FIG. 6 is a plan view showing the spacing of the peripheral conductors 32 of the circuit board 30 and the inner dimensions of the rectangular waveguide 10 of the second embodiment. In addition, in the description of the second embodiment and thereafter, the same or similar members as those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof may be omitted.

In the converter 1 of the first embodiment, the inner dimensions of the rectangular waveguide 10 and the termination tube 20 in the short side direction are also It is also a shortened configuration. On the other hand, in the converter 1 of the second embodiment, the inner dimensions of the rectangular waveguide 10 and the terminal tube 20 in the short side direction are about 1/3 wavelength (that is, length L1=length L0). The interval in the short side direction of the surrounding conductors 32 (the interval in the short side direction between the long side conductors 32La and the long side conductors 32Lb) is the same as in the first embodiment. Further, in the converter 1 of the second embodiment, the peripheral conductor 32 is arranged so as to protrude inward from the inner surfaces of the rectangular waveguide 10 and the termination tube 20 when viewed in the thickness direction of the circuit board 30. ing. More specifically, the inner ends of the long-side conductors 32La and 32Lb have portions located further inside than the inner surface of the rectangular waveguide 10 .

Even with the configuration of the second embodiment, the principle of widening the band explained in the first embodiment holds true. Therefore, a wide band can be realized using a generally available waveguide.

Next, converters 1 of third to sixth embodiments will be described. The transducers 1 of the third to sixth embodiments have structures for reducing the lengths of the terminal tube 20 and the like in various directions. In the converters 1 of the third to sixth embodiments, the configurations of the rectangular waveguide 10 and the circuit board 30 are the same as those of the first embodiment, and the configuration of the termination tube 20 is different from that of the first embodiment. Each embodiment will be described in detail below.

The terminal tube 20 of the converter 1 of the third embodiment shown in FIG. 7 has a portion with a longer inner dimension in the long side direction than the rectangular waveguide 10 (first portion 11). Specifically, the termination pipe 20 of the third embodiment has a rectangular parallelepiped shape, and an opening 20a having the same size as the opening 10a is formed. Therefore, on the closed portion 20b side of the opening portion 20a, the terminal tube 20 has a rectangular parallelepiped internal space with a larger internal dimension in the long side direction than in the first embodiment.

Further, the inventors have confirmed that the same band can be achieved even if the length in the axial direction is shortened by increasing the inner dimension of the inner space of the termination pipe 20 in the long side direction. Therefore, by adopting the termination tube 20 of the third embodiment, it is possible to reduce the axial length of the termination tube 20 and the transducer 1 while maintaining the same band.

The termination tube 20 of the converter 1 of the fourth embodiment shown in FIG. 8 has a longer inner dimension in the long side direction than the rectangular waveguide 10 (first portion 11), as in the third embodiment. have a part. Specifically, a plurality of protrusions 21 projecting in the long-side direction are formed on the outer surface parallel to the short-side direction in the termination pipe 20 of the fourth embodiment. The terminal tube 20 has two outer surfaces parallel to the short side direction, and two protrusions 21 are formed on each outer surface with an interval therebetween. An internal space is also formed inside these protrusions 21 . Therefore, in the portion where the convex portion 21 is formed, the terminal tube 20 has a portion with a longer inner dimension in the long side direction than the rectangular waveguide 10 (the first portion 11). Even with such a shape, the axial lengths of the termination tube 20 and the transducer 1 can be shortened while maintaining the same band as in the third embodiment.

In addition, concave portions 22 surrounded by two convex portions 21 are respectively formed on the two outer surfaces on the short side of the terminal tube 20 . By attaching the termination tube 20 to another member using this recess 22, the length of the transducer 1 in the longitudinal direction including the attachment structure can be reduced.

The termination tube 20 of the transducer 1 of the fifth embodiment shown in FIG. 9 has a portion with a longer inner dimension in the short side direction than the rectangular waveguide 10 (first portion 11). Specifically, in the termination pipe 20 of the fifth embodiment, a plurality of projections 23 (specifically, 2) are formed. An internal space is also formed inside these protrusions 23 . Therefore, in the portion where the convex portion 23 is formed, the termination tube 20 has a portion with a longer inner dimension in the short side direction compared to the rectangular waveguide 10 (first portion 11). Even with such a shape, the axial lengths of the termination tube 20 and the transducer 1 can be shortened while maintaining the same band as in the third and fourth embodiments.

In addition, a concave portion 24 surrounded by two convex portions 23 is formed on the outer surface parallel to the longitudinal direction of the terminal tube 20 . In the fifth embodiment, since the protrusions 23 extend in the short side direction, the termination tube 20 is fixed using, for example, the outer surface of the termination tube 20 in the long side direction. Therefore, the length of the transducer 1 (specifically, the end tube 20) in the long side direction can be shortened. In addition, the structure which attaches the termination pipe 20 to another member using the recessed part 24 may be sufficient.

The terminal tube 20 of the converter 1 of the sixth embodiment shown in FIG. 10 has a portion with a longer inner dimension in the short side direction than the rectangular waveguide 10 (first portion 11). Specifically, the termination tube 20 of the sixth embodiment has a portion with a longer inner dimension in the short side direction at a position farther from the circuit board 30 than the opening 20a. In other words, the terminal tube 20 has a portion where the axial direction changes from the same axial direction as the rectangular waveguide 10 to the same direction as the short side direction of the rectangular waveguide 10 . Even with such a shape, the axial length of the termination tube 20 and the transducer 1 can be shortened while maintaining the same bandwidth.

As described above, the converter 1 of the above embodiment includes the rectangular waveguide 10 and the circuit board 30. As shown in FIG. A signal is transmitted to the rectangular waveguide 10 . The circuit board 30 is connected to the rectangular waveguide 10, and has a conversion portion 31b, which is a conductor for converting the transmission mode of a signal, and a surrounding conductor 32. As shown in FIG. The thickness direction of the circuit board 30 and the transmission direction of the rectangular waveguide 10 are the same. When the circuit board 30 is viewed in the thickness direction, the peripheral conductor 32 is arranged so as to surround at least a portion of the conversion portion 31b. The peripheral conductors 32 include long-side conductors 32La and 32Lb arranged along the long sides of the rectangular waveguide 10 when viewed in the thickness direction of the circuit board 30, and conductors 32La and 32Lb along the short sides of the rectangular waveguide 10. It has short-side conductors 32Sa and 32Sb arranged in the same direction. The long-side conductors 32La and 32Lb are spaced apart in the short-side direction, and the space is equal to or less than a quarter of the wavelength of the signal to be transmitted.

As a result, it is possible to shorten the distance from one conversion unit 31b to another conversion unit 31b while reducing the insertion amount of the conversion units 31b, so that the converter 1 with a wide band can be realized.

Further, in the converter 1 of the present embodiment, in the portion where the rectangular waveguide 10 and the circuit board 30 are connected, the inner dimension of the rectangular waveguide 10 in the short side direction is 4 times the wavelength of the signal to be transmitted. less than one-third.

As a result, the inner positions of the peripheral conductor 32 and the rectangular waveguide 10 can be aligned.

Further, in the converter 1 of the present embodiment, the rectangular waveguide 10 has a portion in which the inner dimension in the short side direction becomes longer with increasing distance from the circuit board 30 along the transmission direction.

As a result, the signal converting portion and the signal transmitting portion can each have an optimum shape.

Further, in the converter 1 of the present embodiment, the inner ends of the long-side conductors 32La and 32Lb have portions located further inside than the inner surface of the rectangular waveguide 10 .

As a result, the band of the converter 1 can be widened using a waveguide having a general inner dimension in the short side direction.

Further, in the converter 1 of the present embodiment, conversion portions (conversion portion 31b and rear conversion portion 41b) are arranged on both sides of the circuit board 30, and the two conversion portions are connected to conductors (through-holes) of the circuit board 30. 33) are electrically connected.

As a result, signals can be converted on both sides of the circuit board 30, so conversion efficiency can be improved.

The transducer 1 of this embodiment also includes a termination tube 20 whose one end is closed with a conductor. A circuit board 30 is sandwiched between the rectangular waveguide 10 and the termination tube 20 . When viewed in the thickness direction of the circuit board 30 , the inner dimension in the long side direction of the termination tube 20 has a portion longer than the inner dimension in the long side direction of the rectangular waveguide 10 . Alternatively, in the converter 1 of the present embodiment, when viewed in the thickness direction of the circuit board 30, the inner dimension of the terminal tube 20 in the short side direction is longer than the inner dimension of the rectangular waveguide 10 in the short side direction. may have parts.

As a result, the length in the direction corresponding to the required specifications can be shortened.

Although the preferred embodiments of the present invention have been described above, the above configuration can be modified, for example, as follows.

The features described in the first to sixth embodiments can be appropriately combined within a range that does not cause contradiction. For example, the feature of the second embodiment in which the peripheral conductor 32 protrudes inward in the short side direction can be applied to any one of the third to sixth embodiments.

In the rectangular waveguide 10 and the termination tube 20, the shape of the internal space rather than the outer shape affects the conversion characteristics. Therefore, the outlines of the rectangular waveguide 10 and the termination tube 20 may be different shapes from those of the above embodiment.

Except for the second embodiment, the peripheral conductor 32, the end surface of the rectangular waveguide 10 facing the circuit board 30, and the end surface of the termination tube 20 facing the circuit board 30 are formed in the same range. may be formed to different extents.

In the above embodiments, the transducer 1 comprises a set of rectangular waveguides 10, termination tubes 20 and circuit boards 30, but multiple sets of rectangular waveguides 10, termination tubes 20 and circuit boards 30 may be used. may be provided.

In the above embodiment, the rectangular waveguide 10 and the termination tube 20 are hollow inside, but at least one of the rectangular waveguide 10 and the termination tube 20 may contain a dielectric inside.

Reference Signs List 1 transducer 10 rectangular waveguide 20 termination tube 30 circuit board 31 linear conductor 31a transmission section 31b conversion section 32 surrounding conductor

Claims (8)

a rectangular waveguide having an internal space formed by a conductor and through which a signal is transmitted in the internal space;
a circuit board connected to the rectangular waveguide, having a first surface and a second surface, and arranged such that a thickness direction thereof coincides with a signal transmission direction;
a termination tube having one end closed with a conductor;
with
The circuit board is
a first converter formed on the first surface of the circuit board and including a conductor for converting a transmission mode of a signal;
a first peripheral conductor formed on the first surface of the circuit board and surrounding at least a portion of the first conversion portion when the circuit board is viewed in the thickness direction;
a second converter formed on the second surface of the circuit board, electrically connected to the first converter, and including a conductor for converting a transmission mode of a signal;
a second peripheral conductor formed on the second surface of the circuit board and surrounding at least a portion of the second conversion portion when the circuit board is viewed in the thickness direction;
with
The circuit board is sandwiched between the rectangular waveguide and the termination tube,
A converter characterized in that, when viewed in the thickness direction of the circuit board, the inner dimension of the termination tube in the long side direction has a portion longer than the inner dimension of the rectangular waveguide in the long side direction . . a rectangular waveguide having an internal space formed by a conductor and through which a signal is transmitted in the internal space;
a circuit board connected to the rectangular waveguide, having a first surface and a second surface, and arranged such that a thickness direction thereof coincides with a signal transmission direction;
a termination tube having one end closed with a conductor;
with
The circuit board is
a first converter formed on the first surface of the circuit board and including a conductor for converting a transmission mode of a signal;
a first peripheral conductor formed on the first surface of the circuit board and surrounding at least a portion of the first conversion portion when the circuit board is viewed in the thickness direction;
a second converter formed on the second surface of the circuit board, electrically connected to the first converter, and including a conductor for converting a transmission mode of a signal;
a second peripheral conductor formed on the second surface of the circuit board and surrounding at least a portion of the second conversion portion when the circuit board is viewed in the thickness direction;
with
The circuit board is sandwiched between the rectangular waveguide and the termination tube,
A converter characterized by having a portion in which the inner dimension in the short side direction of the termination tube is longer than the inner dimension in the short side direction of the rectangular waveguide when viewed in the thickness direction of the circuit board. . 3. A converter according to claim 1 or 2 ,
When viewed in the thickness direction of the circuit board, the first peripheral conductor includes a long-side conductor arranged along the long side of the rectangular waveguide, and a long-side conductor arranged along the short side of the rectangular waveguide. and short-side conductors arranged at
A converter, wherein the long-side conductors are spaced apart in the short-side direction, the spacing being equal to or less than a quarter of the wavelength of a signal to be transmitted. A converter according to any one of claims 1 to 3 ,
Of the first surface and the second surface of the circuit board, only the first surface is provided with a transmission section that is an elongated portion for transmitting a signal,
The converter, wherein the transmission section is connected to the first conversion section. 5. A converter according to claim 4 , wherein
The transducer, wherein the second peripheral conductor surrounds the second transducer over the entire circumference. A converter according to claim 3 , wherein
In the portion where the rectangular waveguide and the circuit board are connected, the inner dimension of the rectangular waveguide in the direction of the short side is 1/4 or less of the wavelength of the signal to be transmitted. converter. 7. A converter according to claim 6 , comprising:
The converter, wherein the rectangular waveguide has a portion whose inner dimension in the short side direction becomes longer with increasing distance from the circuit board along the transmission direction. A converter according to claim 3 , wherein
A converter according to claim 1, characterized in that the inner ends of the long-side conductors have portions positioned further inside than the inner surface of the rectangular waveguide.

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