JP2003298322A - Waveguide/microstrip line transducer and transducer component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact waveguide/microstrip line transducer that can improve poor quality in the characteristics of a mechanism for transducing a transmission basic mode by an electric adjustment. <P>SOLUTION: Metal posts 10, 11, and 12 whose insertion length can be adjusted are provided in a direction that orthogonally crosses at least one of a short- circuiting surface 1a and E surfaces 1b and 1c of a waveguide back short 1 that has the short-circuiting surface 1a in parallel with the electric field of stationary distribution, in a square waveguide 20 for transmitting an electromagnetic wave in a TE10 mode and the E surfaces 1b and 1c. By the metal posts 10, 11, and 12, the characteristics can be post-adjusted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide-microstrip line converter and a converter component used in a microwave band or a millimeter wave band.

[0002]

2. Description of the Related Art As a component for appropriately joining a waveguide and a microstrip line included in a planar circuit with low loss,
A waveguide-microstrip line converter is often used. FIG. 8 is a structural explanatory view of a conventional waveguide-microstrip line converter of this type. In this figure, for convenience of description, the thickness of the waveguide and the like, the shape of the outer wall, etc. are omitted. The waveguide-microstrip line converter shown in FIG. 8 has the microstrip line 31 parallel to the electric field of the steady distribution of the rectangular waveguide 20 whose inner wall long side has a dimension A and whose inner wall short side has a dimension B. The dielectric substrate 30 on which is formed is arranged. The inner end surface of the rectangular waveguide 20 is a short-circuit surface that is parallel to the microstrip line 31. The end portion having the short-circuit surface is usually called a "waveguide back short". In the following description, this end portion will be referred to as a waveguide back short circuit 5. The front end portion (waveguide side) of the microstrip line 31 is opened to form an open end portion 32. The transmission fundamental mode of the rectangular waveguide 20 is the TE10 mode, and the transmission fundamental mode of the microstrip line 31 is the quasi-TEM mode.

FIG. 9 is a sectional view showing the electric field distribution in the conversion mechanism of such a waveguide-microstrip line converter. In FIG. 9, a part of the wall thickness and the outer wall shape of the rectangular waveguide 20 and the waveguide back short 5 are drawn in order to explain the hole portion 1d for passing the microstrip line 31 and the like. As shown in FIG. 9, in the conversion mechanism, the electric field distribution e of the TE10 mode of the rectangular waveguide 20
1 and the quasi-TEM mode electric field distribution e2 of the microstrip line 31 are converted while being disturbed in the inside of the rectangular waveguide 20 and the cavity (internal space) of the waveguide back short circuit 5. There is.

FIG. 10 is an equivalent circuit of a waveguide-microstrip line converter, which shows a T in a rectangular waveguide 20.
The characteristic impedance of the E10 mode transmission line 20 'is Z
1. It is shown that the characteristic impedance of the quasi-TEM mode transmission line 31 ′ in the microstrip line 31 which is branched and joined (point aa ′) is Z2. In the waveguide-microstrip line converter, these characteristic impedances Z1 and Z2 must be properly matched. Therefore, the length of the waveguide back short 5 (the length from the microstrip line 31 to the short-circuit point 50 '(short-circuit surface 50 of the waveguide back short 5 in FIG. 9): hereinafter referred to as "short-circuit line length". ) L and
The size of the open end 32 of the microstrip line 31 is
It is selected as an eigenvalue according to the size of the rectangular waveguide 20, the thickness / relative permittivity of the dielectric substrate 30, and the used frequency.

As shown in FIG. 11, the dielectric substrate 30 has the same end size as the long side inner wall size A of the rectangular waveguide 20 and is in contact with the cavity of the waveguide back short 5. The length of the portion (the length in the downward direction from the portion indicated by the broken line in FIG. 11) is the same as the dimension B of the short side of the inner wall of the rectangular waveguide 20. Microstrip line 31
The line width W1 of is uniquely determined according to the set characteristic impedance. The width W2 of the open end portion 32 is slightly wider than the line width W1 of the microstrip line 31, and the open end portion 32 is sized to enter the waveguide inward direction from the long side surface of the rectangular waveguide 20 by a length T. Width W2 and length T of open end 32
Is uniquely determined according to the inner wall size of the rectangular waveguide 20 and the material of the dielectric substrate 30 mainly for the purpose of impedance matching.

FIG. 12 is a schematic view of the waveguide back short circuit 5. The waveguide back short 5 is a rectangular waveguide 20.
The inner end surface that is parallel to the electric field in the steady distribution when joined to is the short-circuit surface 50, the pair of inner side surfaces is the E surface, and the notch 53 as shown is formed in a part of the upper long side surface. Consists of In order to facilitate the joining with the rectangular waveguide 20, the flange 51 having the plurality of holes 52 may be integrally molded with the back short outer wall. At the time of use, the dielectric substrate 30 is sandwiched and bonded to the rectangular waveguide 20. The joining is performed by inserting a dedicated screw into the hole 52 of the flange 51 after positioning with the rectangular waveguide 20. The size of the opening of the waveguide back short 5 is the same as the size of the opening of the rectangular waveguide 20. That is, the dimension of the long side of the inner wall is A, and the dimension of the short side of the inner wall is B.

The reflection characteristic of the conventional waveguide-microstrip line converter configured as described above is as shown in FIG. Originally, the reflected wave generated due to the conversion of the transmission fundamental mode is unnecessary, and in order to avoid such an adverse effect of the reflected wave within the required band, the reflection attenuation amount is −20.
It is designed to achieve dB or less. Regarding the structure and operation of the above-mentioned waveguide-microstrip line converter, JP-A-60-230701 and US Pat.
The description of No. 48 can be referred to.

[0008]

The above-described conventional waveguide-microstrip line converter has the following problems to be solved. The first problem is that impedance matching is difficult within the required band. In the equivalent circuit of FIG. 10, the basic required performance as a waveguide-microstrip line converter is that the characteristic impedance Z1 of the TE10 mode transmission line 20 'and the characteristic impedance Z2 of the quasi-TEM mode transmission line 31' are not satisfied. There is no consistency. Normally, the characteristic impedance Z1 at the operating frequency is 300 ohms to 500 ohms (defined by voltage and current), and the characteristic impedance Z2 is selected to be 50 ohms. Although it is not easy to match characteristic impedances that have a large difference in this way, the fact that the electromagnetic field distribution itself is completely different in a waveguide-microstrip line converter makes impedance matching difficult. Has become a factor.

In manufacturing, the waveguide back short 5
The short circuit line length L, the width W2 and the length T of the open end 32 are selected to be the optimum values obtained by calculation in advance and processed, but due to the processing accuracy, the optimum values deviate from the calculated values. However, the reflection characteristics may be deteriorated. If this deterioration of the reflection characteristics becomes a value that cannot be ignored, it will lead to deterioration of the performance of the waveguide-microstrip line converter or the entire device equipped with it, so measures to add "wideband matching" or "matching adjustment function" Is required.

The second problem is that the waveguide back short circuit 5 cannot be miniaturized. The size of the rectangular waveguide 20 is
Since the lower the frequency used, the larger the size, the physical size of the waveguide back short 5 also increases accordingly.
In the equivalent circuit of FIG. 10, the short circuit line length L is aa ′
Since the length needs to be “open” when the short circuit side is viewed from the point, it is selected to be near the quarter wavelength of the guide wavelength of the rectangular waveguide 20. Therefore, in the microwave band 10
When manufacturing a waveguide-microstrip line converter used in a frequency band of GHz or lower, the size of the waveguide back short 5 becomes a neck.

The present invention solves these problems, and has an improved waveguide-microstrip line converter capable of electrically adjusting the characteristics of the conversion mechanism that is determined according to the physical structure, such as the reflection characteristics. And to provide a converter component.

[0012]

According to the present invention, while maintaining the conversion performance of the transmission fundamental mode, for example, the guide wavelength can be increased or decreased equivalently, whereby the characteristics of the conversion mechanism can be adjusted afterwards. Provided is a waveguide-microstrip line converter capable of performing the same. This waveguide-microstrip line converter is provided with a conversion mechanism for converting the transmission fundamental mode between the waveguide and the microstrip line arranged in parallel with the electric field of the steady distribution in the waveguide,
In the waveguide-microstrip line converter in which the characteristic of the conversion mechanism is determined according to the physical structure of the predetermined portion of the waveguide, a metal member that electrically changes the conversion characteristic is provided at the predetermined portion. It has been deployed. The “characteristics” here are, for example, the above-mentioned reflection characteristics, impedance characteristics, and other electric characteristics. The "physical structure" is, for example, the above-described inner wall long side, inner wall short side, and short circuit line length. In such a waveguide-microstrip line converter, since the electric field distribution in the waveguide is concentrated on the metal member,
It allows for the posterior adjustment of properties.

The transmission fundamental mode of the waveguide is a TE10 mode, the transmission fundamental mode of the microstrip line is a quasi-TEM mode, and the predetermined portion is a short-circuit plane parallel to an electric field of a steady distribution in the waveguide. In the case of a waveguide end having an inner end face and two E faces on its inner side face, the metal member is arranged in a direction orthogonal to each of the short circuit face and the two E faces. Will be deployed.
A configuration in which the metal member is provided only on the short-circuit surface or only on the two E surfaces is also possible. In either case, it is desirable that the size of protrusion from each surface into the waveguide can be adjusted. The metal member has a predetermined shape and is supported by the outer wall of the end portion of the waveguide so that the length of insertion into the waveguide can be adjusted. It may be a screw having a screwing mechanism.

The end portion of the waveguide may be a resin molded product in which a part or all of the surface thereof is metallized, and a part of the metal member is fixed to the resin molded product. It may be one. By doing so, mass production is facilitated and a significant cost reduction is possible.

Another waveguide-microstrip line converter of the present invention comprises a TE10 mode waveguide and a quasi-TEM mode microstrip line which is arranged in parallel with an electric field of a steady distribution in the waveguide. A conversion mechanism for converting the transmission fundamental mode between the two is provided, and the characteristics of the conversion mechanism are determined according to the physical structure of the end of the waveguide in which the cavity in contact with the microstrip line is formed. In the wave tube-microstrip line converter, a dielectric that changes the conversion characteristics according to the shape and relative permittivity of the cavity is exchangeably arranged in the cavity. The entire space of the cavity may be filled with a dielectric that changes the conversion characteristic according to its shape and relative permittivity. In this way, the transducer size can be made smaller while allowing the required characteristics to be adjusted. The waveguide end back short circuit can be formed of a resin molded product in which a part or all of the surface thereof is metallized.

The transducer component of the present invention converts the fundamental mode of transmission between a TE10 mode waveguide and a quasi-TEM mode microstrip line arranged parallel to the steady-state electric field in the waveguide. Which is used in a waveguide-microstrip line converter having a short-circuit surface parallel to the electric field of a steady distribution in the waveguide at its inner end surface, and has two E surfaces. A metal member is provided on each of the short-circuit surface and the two E surfaces on the inner side surface in a direction orthogonal to the surface, and the metal member has a size that protrudes into the waveguide. Is adjustable, and the conversion characteristic is electrically changed according to the protruding size. A part or all of the surface of the converter component may be molded with a metallized resin, and a part of the metal member may be fixed to the resin.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a structural explanatory view of a waveguide-microstrip line converter according to a first embodiment of the present invention. For the sake of convenience, the same components as those of the conventional one shown in FIG. 1 is the same as FIG. 8 in that the thickness of the rectangular waveguide 20 and the like and the shape of the outer wall are omitted. Further, the dielectric substrate 30 on which the microstrip line 31 is formed is arranged in parallel to the electric field of the steady distribution of the rectangular waveguide 20, and the open end 32 is formed at the tip of the microstrip line 31. Is the same as that shown in FIG. The transmission fundamental mode of the rectangular waveguide 20 is the TE10 mode, and the microstrip line 3
The basic transmission mode of 1 is the quasi-TEM mode.

In the waveguide-microstrip line converter of this embodiment, the structure of the waveguide back short circuit is as shown in FIG.
It is different from the waveguide back short circuit 5 shown in (However, the point that it is made of a conductive member is the same). The waveguide back short circuit 1 of this embodiment has a structure in which the short circuit line length L is equivalently increased or decreased to thereby match the impedance during mode conversion. Specifically, on each of the short-circuit surface 1a and the two E surfaces 1b and 1c of the waveguide back short circuit 1, metal posts 10, 11 and 1 which are examples of metal members are provided.
2 in the direction perpendicular to each surface, and each metal post 1
The insertion length of 0, 11, and 12 into the waveguide back short circuit 1, that is, the protrusion size from the short circuit surface is made variable, thereby realizing an adjusting mechanism for posterior impedance matching. The positions where the metal posts 10, 11, 12 are arranged on the respective surfaces 1a1b, 1c may be arbitrary, but it is desirable that the positions be near the center. The metal posts 10, 11,
12 may be supported by the outer wall hole portion, or may be supported by a reciprocating support mechanism attached to the outer wall surface. The metal post itself may expand and contract. Also, the metal posts 10, 1
Instead of 1 and 12, screw-in type metal screws (metal screws) may be used.

When the metal post 10 is inserted in the short-circuit surface 1a of the waveguide back short circuit 1, the electric field distribution is changed to the metal post 10.
Therefore, the short circuit line length L can be equivalently made variable. In the case of the metal posts 11 and 12 arranged perpendicularly to the E faces 1b and 1c, the dimension A of the long side of the inner wall is equivalently shortened, and TE1 in the waveguide back short 1 is reduced.
The guide wavelength in the 0 mode can be lengthened. That is, even if the length L of the short circuit line is constant, the electrical angle Φ of the short circuit line decreases by the length of the guide wavelength.

The relationship between the dimension A of the long side of the inner wall of the TE10 mode and the guide wavelength λgo is expressed by the following equation. λgo = λo / √X X = 1- (λo / (2A)) ² (1) where λo is a free space wavelength. The short-circuit line electrical angle Φ is represented by the following formula. Φ = 2πL / λgo (2)

Since the metal posts 10, 11 and 12 act independently on the electric field, it is not necessary to use three metal posts at the same time as shown in the figure, and only one or two may be used. . Also, the metal posts 10, 11, 1
The number of 2 used may be arbitrarily determined depending on the performance required for the waveguide-microstrip line converter and the processing accuracy of the waveguide back short 1.

FIG. 2 is a diagram showing an electric field distribution in the converter in the waveguide-microstrip line converter according to this embodiment. In both the TE10 mode in the rectangular waveguide 20 and the quasi-TEM mode in the microstrip line, the direction of the electric field is actually inverted every half wavelength,
In FIG. 2, in order to prioritize understanding of the concept, each mode shows a distribution within a half wavelength. In addition, the metal posts are only those provided on the short-circuit surface. In the case of the example shown in FIG. 2, the electric field distribution is concentrated on the metal post 10. If the insertion length S is increased, the short circuit line length L is shortened equivalently, and conversely, if the insertion length S is shortened. , Equivalently short circuit line length L
Becomes longer. In this way, even if the short circuit line length L is constant, the electrical angle of the short circuit line decreases as the guide wavelength increases. By varying the insertion amount S of the metal post 10, the short circuit line length L can be arbitrarily adjusted. Also with respect to the metal posts 11 and 12, the longer the insertion length, the shorter the dimension A of the long side of the inner wall becomes equivalent, so that the guide wavelength of the TE10 mode transmitted in the waveguide back short can be lengthened.

As an example of the characteristics of the waveguide-microstrip line converter that changes according to this embodiment, 17G
The reflection characteristics in the Hz band are shown in FIG. It will be understood that the reflection characteristics are improved as compared with the reflection characteristics of the conventional waveguide-microstrip line converter shown in FIG.

<Second Embodiment> FIG. 3 shows the structure of a waveguide-microstrip line converter according to a second embodiment of the present invention. For convenience, the same components as those of the conventional one shown in FIG. 8 are designated by the same reference numerals. 3 is the same as FIGS. 1 and 8 in that the thickness of the rectangular waveguide 20, etc., the shape of the outer wall, etc. are omitted. Further, an open end 32 is formed at the tip of the microstrip line 31, at the point where the dielectric substrate 30 having the microstrip line 31 is arranged in parallel with the steady electric field of the rectangular waveguide 20. The points are the same as those shown in FIGS. 1 and 8. Since it is a rectangular waveguide 20, its transmission fundamental mode is T
The E10 mode and the basic transmission mode of the microstrip line 31 are the quasi-TEM modes.

In this embodiment, the dielectric 13 is provided in the cavity in the waveguide back short 2 so as to be exchangeable. As the material of the dielectric 13, for example, the relative permittivity εr
2 can be used. TE1 when the dielectric 13 is present in the cavity
The 0-mode guide wavelength λg can be expressed by the following formula. λg = λgo / √ (η ・ εr) (3) where η is the dielectric filling factor (the ratio of the dielectric to the entire cavity space), εr is the relative permittivity of the dielectric, and λgo is εr Is the guide wavelength when is "1".

The above-mentioned dielectric filling factor η and relative permittivity εr
By changing the wavelength, it is possible to change the guide wavelength λgo, and it is possible to adjust the characteristics of the conversion mechanism in the waveguide-microstrip line converter, for example, the above-mentioned short-circuit line electrical angle Φ afterwards. . Dielectric filling factor η
Is determined by the size of the dielectric, and the relative permittivity εr is determined by the type of the dielectric.

The shape of the dielectric 13 can be freely selected. Depending on this shape and the value of the relative permittivity εr, the reflected wave itself by the dielectric itself may contribute to impedance matching. The range that can be electrically adjusted is expanded.

In FIG. 3, Teflon (registered trademark) processed into a step shape is used as the dielectric 13, but this is
When the size of the waveguide-microstrip line converter is in the millimeter wave band, the size is sufficiently small,
This is because the impedance characteristics are improved, that is, the impedance matching is emphasized rather than the size reduction. By processing into a step shape and changing the position of the dielectric 13, it becomes easy to adjust the impedance characteristic afterwards. That is, the impedance value can be changed stepwise by changing the position and shape of the step, and the value can be finely adjusted by changing the position of the dielectric 13.

FIG. 4 is a diagram showing the electric field distribution of the converter in the waveguide-microstrip line converter according to the second embodiment. As is clear from FIG. 4, the electric field distribution is
It changes according to the shape of the dielectric 13. Therefore, by making the short circuit line lengths L1, L2, L3 variable, the fine adjustment can be performed. The dielectric 13 includes a stepped dielectric 13 as shown in FIG. 5A, a tapered dielectric 14 as shown in FIG. 5B, and a planar dielectric as shown in FIG. 5C. It is also possible to use 15. In the tapered dielectric 14, since the impedance changes in a tapered shape,
Adjustment of impedance characteristics becomes easier.

<Third Embodiment> FIG. 6 is a schematic view of a waveguide back short circuit in a waveguide-microstrip line converter according to a third embodiment. The illustrated waveguide back short 3 is obtained by replacing the waveguide back short made of the conductive member described in the first embodiment with a plastic molded product. At that time, in order to make the electromagnetic field boundary condition equivalent to that of the metal processed product (waveguide back short 1 of the first embodiment), the outer surface and the inner surface of the plastic molded product are metallized. Reference numerals 40, 41 and 42 denote metallized posts which have been metallized and whose positions are fixed.

Although the technique of metallizing on the surface of plastic is general, the film thickness at the time of metallizing treatment sufficient to guarantee the predetermined transmission characteristics in the microwave band and the millimeter wave band is, of course, highly accurate. Required to be present.
According to the experiments by the present inventors, by setting the film thickness to be 5 times or more of the skin dips value that can be uniquely calculated by the type of metal used for the metallizing process and the transmission frequency, it is almost the same as that of the conductive member. It has been found that the characteristic is a waveguide back short 3.

FIG. 7 shows the metallized post 4 shown in FIG.
When the electrical characteristics are not stable with 0, 41, and 42, and the insertion length in the cavity direction needs to be changed, metal screws 43, 44 are used so that the insertion length of some or all of the posts can be changed. , 45.

<Fourth Embodiment> In the second embodiment, an example in which the dielectric 13 is arranged in the cavity in a replaceable manner has been described, but the dielectric is not limited to a part of the waveguide back short circuit. , May be filled throughout.
For example, the second problem described above can be easily solved by filling a dielectric having a relative dielectric constant of 4.0 with a filling rate of 100%.

When the conventional waveguide-microstrip line converter in the 10 GHz band is constructed as an example, the degree of improvement is clear. That is,
The rectangular waveguide 20 is WR90 (EIA standard), the dimension A of the long side of the inner wall is 22.86 mm, and the dimension B of the short side of the inner wall is 1.
The characteristic impedance (defined by voltage and current) Z1 at 10 GHz which is 0.16 mm is 348 ohms. When this is mode-converted into the microstrip line 31 having a characteristic impedance Z2 of 50 ohms, 10 mm is required if the short circuit line length L of the waveguide back short is selected to be 1/4 wavelength (internal wavelength). However, if the cavity in the waveguide back short is filled with a dielectric having a relative dielectric constant of 4.0 at a filling rate of 100%, the short circuit line length L of the waveguide back short can be shortened to 5 mm. This means that the in-tube wavelength of the waveguide was shortened by filling the dielectric material. The relationship between the dielectric constant of the filled dielectric and the wavelength in the tube is the same as in the above equation (3).

[0035]

As described above, according to the present invention,
For example, it is possible to obtain a peculiar effect that characteristic defects (impedance mismatch, etc.) resulting from physical structural changes or defects such as variations in processing of the end portion of the waveguide can be improved afterwards.

[Brief description of drawings]

FIG. 1 is a schematic view of a waveguide-microstrip line converter according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a converter electric field distribution of the waveguide-microstrip line converter according to the first embodiment.

FIG. 3 is a schematic view of a waveguide-microstrip line converter according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a converter electric field distribution of the waveguide-microstrip line converter according to the second embodiment.

5A and 5B are diagrams showing the shape of a dielectric, wherein FIG. 5A shows an example of a stepped dielectric, FIG. 5B shows a tapered dielectric, and FIG. 5C shows an example of a linear dielectric.

FIG. 6 is an explanatory diagram of a waveguide back short circuit whose surface is metallized.

FIG. 7 is an explanatory diagram of a waveguide back short circuit in which the surface thereof and the surface of a molded metal post are metallized.

FIG. 8 is a schematic view of a conventional waveguide-microstrip line converter.

FIG. 9 is an explanatory diagram of a conversion unit electric field distribution of a conventional waveguide-microstrip line converter.

FIG. 10 is an equivalent circuit of a waveguide-microstrip line converter.

FIG. 11 is a structural explanatory view of a dielectric substrate on which a microstrip line is formed.

FIG. 12 is a schematic view of a conventional waveguide back short circuit.

FIG. 13 is a reflection characteristic diagram of a conventional waveguide-microstrip line converter.

FIG. 14 is a reflection characteristic diagram of the waveguide-microstrip line converter according to the first embodiment.

[Explanation of symbols]

1, 2, 3, 5 Waveguide back-short 1a, 50 Short-circuit surface 1b, 1c E-plane 1d Holes 10, 11 and 12 for passing microstrip line, Metal post (screw, screw) 40, 41, 42,43,44,45 Metallized post (screw,
Screws) 13, 14, 15 Dielectric 20 Rectangular Waveguide 30 Dielectric Plate 31 Microstrip Line 32 Open End 51 Flange 52 Screw Hole 53 Notch

Claims (10)

[Claims] 1. A conversion mechanism for converting a fundamental mode of transmission between a waveguide and a microstrip line arranged in parallel with an electric field of a steady distribution in the waveguide, the conversion mechanism having the characteristics described above. In the waveguide-microstrip line converter determined according to the physical structure of a predetermined portion of the waveguide, a metal member that electrically changes the conversion characteristic is provided at the predetermined portion. , Waveguide-microstrip line converter. 2. The transmission fundamental mode of the waveguide is TE10.
Mode, the transmission basic mode of the microstrip line is a quasi-TEM mode, the predetermined portion is a waveguide end having a short-circuit surface parallel to the microstrip line at its inner end surface, and the metal member is The waveguide-microstrip line converter according to claim 1, wherein the waveguide-microstrip line converter is arranged in a direction orthogonal to the short-circuit surface, and a size protruding from the short-circuit surface into the waveguide is adjustable. 3. The transmission fundamental mode of the waveguide is TE10.
Mode, the transmission fundamental mode of the microstrip line is a quasi-TEM mode, the predetermined portion is a waveguide end having two E-planes on its inner surface, and the metal member is at least one of the two E-planes. The waveguide-microstrip line converter according to claim 1, wherein the waveguide-microstrip line converter is arranged in a direction orthogonal to one surface, and a size of projecting from each E surface into the waveguide is adjustable. 4. The transmission fundamental mode of the waveguide is TE10.
Mode, the transmission fundamental mode of the microstrip line is a quasi-TEM mode, the predetermined part has a short-circuit surface parallel to an electric field of a steady distribution in the waveguide, and has two E surfaces. It is a waveguide end portion having an inner surface thereof, wherein the metal member is arranged in a direction orthogonal to each of the short-circuit surface and the two E surfaces, and protrudes into the waveguide from each surface. The waveguide-microstrip line converter according to claim 1, characterized in that the size is adjustable. 5. A conversion mechanism for converting a transmission fundamental mode between a TE10 mode waveguide and a quasi-TEM mode microstrip line arranged in parallel with an electric field of a steady distribution in the waveguide, In the waveguide-microstrip line converter, the characteristics of the conversion mechanism are determined according to the physical structure of the end of the waveguide in which a cavity in contact with the microstrip line is formed. A waveguide-microstrip line converter characterized in that a dielectric that changes the conversion characteristics according to its shape and relative permittivity is provided so as to be exchangeable. 6. A conversion mechanism for converting a transmission fundamental mode between a TE10 mode waveguide and a quasi-TEM mode microstrip line arranged in parallel with an electric field of a steady distribution in the waveguide, In the waveguide-microstrip line converter, the characteristics of the conversion mechanism are determined according to the physical structure of the end of the waveguide in which the cavity in contact with the microstrip line is formed. A waveguide-microstrip line converter, characterized in that the space is filled with a dielectric that changes the conversion characteristics according to the shape and relative permittivity thereof. 7. The waveguide according to claim 1, wherein the end portion of the waveguide is a resin molded product in which a part or all of the surface thereof is metallized. A microstrip line converter. 8. The end portion of the waveguide is a resin-molded product in which a part or the whole of the surface thereof is metallized, and a part of the metal member is fixed to the resin-molded product. The waveguide-microstrip line converter according to claim 2, 3, or 4. 9. A waveguide-micro converter for converting a transmission fundamental mode between a TE10 mode waveguide and a quasi-TEM mode microstrip line arranged in parallel with a steady distribution electric field in the waveguide. A converter component used in a stripline converter, which has a short-circuit surface parallel to an electric field of a steady distribution in the waveguide on its inner end surface, and has two E surfaces on its inner surface, A metal member is provided on each of the short-circuit surface and the two E surfaces in a direction orthogonal to the surface, and the metal member has an adjustable size protruding into the waveguide. A converter component, wherein the conversion characteristic is electrically changed according to the protruding size. 10. A part or all of the surface of the metal member is molded with a metallized resin, and a part of the metal member is fixed to the resin.
The converter component according to claim 9.