JPH0590810A - Dielectric waveguide type directional coupler - Google Patents

Abstract

(57) [Summary] [Object] To provide a waveguide type directional coupler that can be miniaturized and can easily obtain desired characteristics including matching with input / output impedance. Constitution: Conductor films 2b, 4b are formed on the side surfaces of the main waveguide portion 2 and the sub-waveguide portion 4 arranged in parallel except the opposing side surfaces of the dielectric blocks 2a, 4a, and further, the dielectric blocks 2a, 4a. Has an electrode film formed on its end face, and the electrode film can be connected to a conductor on a side surface other than the side surface on which the conductor film is not formed and the side surface opposite to the side surface.
c, 4c, the inductance portions 2d, 4d having one end connected to the side surface opposite to the side surface on which the conductor film is not formed and the other end connected to the main body portion, and the main body portions 2c, 4c. It has capacitance parts 2e and 4e extending toward the side surface where the conductor film is not formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type directional coupler used in the UHF band and the SHF band,
In particular, the present invention relates to a dielectric waveguide type directional coupler in which a conductor is coated on a part of an outer surface of a dielectric material such as ceramics to form a waveguide.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a conventional waveguide type directional coupler, (a) is an external view and (b) is a sectional view. The main waveguide and the sub-waveguide are joined to each other as shown in the drawing, and an opening A and an opening B are formed at the joining portion with a distance of 1/4 of the waveguide internal wavelength λg. ing. Most of the wave incident from the main waveguide opening 11 passes through the main waveguide opening 13, but a part of the wave passes through the openings A and B and propagates into the sub-waveguide. Of the waves that have passed through the two openings A and B, the wave that propagates rightward toward the sub-waveguide opening 14 has no propagation path difference to the right of the position B ′ corresponding to the opening B. Therefore, they have the same phase and join each other to reach the sub-waveguide opening 14. In contrast,
The waves propagating toward the sub-waveguide opening 12 to the left have opposite phases because there is a half-wavelength propagation path difference to the left of the position A ′ corresponding to the aperture A, and they cancel each other out. It does not reach the waveguide opening 12.

Such a conventional waveguide type directional coupler has a drawback that the size of the waveguide becomes large in the case of a low frequency wave, which is not preferable in practice. For example,
At 1.5 GHz, the waveguide size is 165 × 82.
The length is 5 mm, and the length of 1/4 of the wavelength λg in the tube (the distance between the openings A and B) is 250 mm. Further, in the above conventional waveguide type directional coupler, the characteristics cannot be changed as necessary.

Therefore, a dielectric waveguide type directional coupler has been proposed in which a conductor film is formed on the surface of a dielectric for the purpose of miniaturization. However, in the conventionally proposed dielectric waveguide type directional coupler, the shape of the electrodes for input and output is simple, so in order to match the input and output impedance, stubs etc. It was necessary to form a matching circuit.

In view of the above prior art, the present invention provides a waveguide type directional coupler which can be miniaturized and can easily obtain desired characteristics including matching with input / output impedance. The purpose is to do.

[0006]

According to the present invention, in order to achieve the above object, a main waveguide portion and a sub-waveguide portion each having a conductor formed on the surface of a dielectric are arranged in parallel. The conductors are formed on the side surfaces of the main waveguide portion and the sub-waveguide portion excluding the side surface facing the other, and the conductors are formed on the end faces of the main waveguide portion and the sub-waveguide portion. Provided is a dielectric waveguide type directional coupler, wherein an electrode film for output is formed, and the electrode film has an inductance part and / or a capacitance part.

In the present invention, the electrode film is connected to a conductor on a side surface other than the side surface on which the conductor is not formed and the side surface opposite to the side surface, and a side surface on which the conductor is not formed. An inductance part having one end connected to the opposite side surface and the other end connected to the main body part;
And a capacitance portion extending from the main body portion toward the side surface on which the conductor is not formed and / or opposite thereto.

Further, in the present invention, there is an aspect in which the main waveguide portion and the sub-waveguide portion are formed of different dielectric blocks, and a means for maintaining them at a desired interval is provided. .. Here, as a means for maintaining the main waveguide portion and the sub-waveguide portion at a desired distance, a dielectric block different from them is sandwiched between the main waveguide portion and the sub-waveguide portion. You can

Furthermore, in the present invention, there is an aspect in which the main waveguide portion and the sub-waveguide portion are formed by using different portions of a single dielectric block.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing a first embodiment of the directional coupler according to the present invention. In the figure, reference numeral 2 is a main waveguide portion, and 4 is a sub-waveguide portion, which are in a form in which rectangular parallelepiped blocks (length L, width W, height H) are arranged in parallel. The main waveguide portion 2 has a conductor film (eg, a conductor film) on three side surfaces of the four side surfaces extending in the longitudinal direction of the rectangular parallelepiped high-dielectric-constant dielectric block 2a, except one side surface facing the sub-waveguide portion 4. A silver film) 2b is provided, and electrode film main portions 2c are provided on both end faces in the longitudinal direction so as to be electrically connected to the conductor film 2b. The electrode film main body 2c has a linear shape extending in parallel (that is, in the vertical direction) with the side surface (that is, the side surface on which the conductor film is not formed) facing the sub-waveguide portion 4. However, the lower edge portion of the electrode film main portion 2c is not electrically connected to the conductor film provided on the lower surface of the dielectric block 2a and is separated. That is, the lower surface of the dielectric block 2a has a region in which the conductor film 2b is not partially formed for this separation. In addition, the conductor film provided on the side surface opposite to the side surface facing the sub-waveguide portion 4 and the electrode film main body portion 2c are connected to the end surface of the dielectric block on which the electrode film main portion 2c is formed. Thus, the electrode film inductance portion 2d extending in the horizontal direction is provided. Furthermore, the electrode film main body 2c is formed on the end surface of the dielectric block on which the electrode film main body 2c is formed.
To the side surface where the conductor film is not formed is provided with the electrode film capacitance portion 2e extending in the horizontal direction. The electrode film main body portion 2c, the electrode film inductance portion 2d, and the electrode film capacitance portion 2e are made of, for example, a silver film.

The main waveguide portion 2 has its dielectric block 2a.
It is mounted on a dielectric substrate 3 having a lower dielectric constant. An input / output microstrip line pattern (for example, a copper film) 3a is formed on the front surface of the dielectric substrate 3 so as to be electrically connected to the electrode film main body 2c, and a ground conductor film (not shown) is formed on the back surface. Are formed.

The sub-waveguide portion 4 side is provided with the main waveguide portion 2
The same configuration as the side is arranged in plane symmetry,
Here, 4a is a high dielectric constant dielectric block, 4b is a conductor film, 4c is an electrode film main part, 4d is an electrode film inductance part, and 4e is an electrode film capacitance part. Further, 5 is a dielectric substrate, and 5a is a microstrip line pattern. The dielectric substrate 3 and the dielectric substrate 5 are composed of dielectric blocks 2a and 4a.
Are arranged by using a gap adjusting means (not shown) so that the surfaces facing each other are parallel to each other with a gap (gap) G therebetween.

The dimensions L, W, H and G can be appropriately set according to desired characteristics. In particular, the dimension G can be changed by the gap adjusting means. Further, the electrode film main parts 2c and 4c, the electrode film inductance part 2
The shapes and dimensions of d and 4d and the electrode film capacitance portions 2e and 4e can be appropriately set so as to obtain good matching with the input / output impedance.

In this embodiment, the dielectric block 2a,
4a having a relative permittivity ε _r of about 93 is used, and dielectric substrates 3 and 5 having a relative permittivity ε _r of about 4 are used.
= 10 mm, W = 5 mm, H = 5 mm, G = 1 mm, the electrode film main body portions 2c and 4c having a width of 1 mm are arranged at the center in the left-right direction, and the electrode film inductance portion 2d,
4d having a width of 1 mm is arranged in the vertical center,
2 and 3 show characteristic measurement results when the electrode film capacitance portions 2e and 4e having a width of 1 mm and a length of 1 mm are arranged at the center in the vertical direction.

In FIG. 2, as shown in FIG. 1, the end portions of the two line patterns 3a on the main waveguide portion 2 side are shown by P1 and P2.
Then, the end portions of the two line patterns 5a on the side of the sub-waveguide portion 4 are designated as P3 and P4, and the signal power is inputted from P1,
Electric powers S ₂₁ , S output from P2, P3, P4, respectively
_The results of measuring the electric power S ₁₁ reflected and output at ₃₁ , S ₄₁ and P1 are shown. As can be seen from FIG. 2, the power input from P1 is output to P2 and P4 in a bandwidth of about 500 MHz, but is not output to P3, and the function of the directional coupler is exhibited. The same applies when the signal power is input from P2, P3, and P4.

The coupling amount (S ₄₁ ) can be changed by changing the dimension L and the dimension G, and a directional coupler having desired characteristics can be manufactured.

FIG. 3 is a Smith chart of the reflected powers of P1 and P2. No matching circuit is provided in the microstrip line pattern.

In order to compare the matching with the input / output impedance, the directional coupler shown in FIG. 4 was prepared as a comparative example. 4, members having the same functions as those in FIG. 1 are designated by the same reference numerals. This comparative example is different from the above-described embodiments of the present invention only in the structure of the electrode film, and is composed of only main parts 2a and 4a having a width of 1.6 mm which are adjacent to the side surface of the dielectric block 2 on which the conductor film is not formed. The rest is the same as the embodiment of the present invention shown in FIG. 1 including dimensions. FIG. 5 is a Smith chart of the reflected powers of P1 and P2 in this comparative example. No matching circuit is provided in the microstrip line pattern.

As can be seen from the comparison between FIG. 3 and FIG. 5, in the case of the embodiment of the present invention, since the electrode film is composed of the main body portion, the inductance portion and the capacitance portion, the matching circuit may not be provided in the microstrip line pattern. While the matching with the input / output impedance is excellent, in the comparative example, the electrode film consists of only the main part, so if the matching circuit is not provided in the microstrip line pattern, the matching with the input / output impedance is performed. It is not removed.

FIG. 6 is a schematic perspective view showing a second embodiment of the directional coupler according to the present invention. In the figure, 2 is a main waveguide portion, 4 is a sub-waveguide portion, and these are rectangular parallelepiped shapes as in the first embodiment. However, in this embodiment, the dielectric block is an integral type in which the main waveguide portion 2a 'and the sub-waveguide portion 4a' are connected by the intermediate portion 6. That is, the dielectric block has a rectangular parallelepiped shape having a width W as a whole, a part of which constitutes the main waveguide portion, a part of which constitutes the sub-waveguide portion, and an intermediate portion between them. Thus, the distance between the main waveguide portion and the sub-waveguide portion is kept constant. Further, a groove 6a having a width G and a depth D is formed in the upper part of the intermediate portion. The main waveguide portion 2 and the sub-waveguide portion 4 are mounted on the common dielectric substrate 7. 3a and 5a are microstrip line patterns.

In this embodiment, a dielectric block having a relative permittivity ε _r of about 93 is used, and a dielectric substrate 7 having a relative permittivity ε _r of about 4 is used. L = 10 mm, W
= 12 mm, H = 5 mm, G = 3.0 mm, D = 1.8
FIG. 7 shows the characteristic measurement result when the thickness is mm. This measurement was performed in the same manner as in the case of the first embodiment. As can be seen from FIG. 7, the power input from P1 is about 500.
In the bandwidth of MHz, it is output to P2 and P4 but is not output to P3, and it can be seen that the function of the directional coupler is exerted. The same applies when the signal power is input from P2, P3, and P4.

In the present embodiment, the coupling amount can be changed also by appropriately setting the shape and dimension of the groove 6a. In addition, for example, when L was 19 mm, the directional coupling function could be exhibited in the bandwidth of about 1000 MHz.

By using an integral dielectric block as in this embodiment, a directional coupler having a low cost and less variation in characteristics can be obtained.

FIG. 8 is a partial schematic perspective view showing a third embodiment of the directional coupler according to the present invention. Although the illustration of the dielectric substrate and the microstrip line pattern is omitted in this figure, this is the same as in the second embodiment.

In this embodiment, the dielectric block 8 is interposed between the dielectric block 2a of the main waveguide portion and the dielectric block 4a of the sub-waveguide portion. That is, the dielectric block 8 maintains a constant distance between the main waveguide portion 2 and the sub-waveguide portion 4. In this embodiment, the thickness of the dielectric block 8 is appropriately selected to set the distance between the dielectric block 2a of the main waveguide portion and the dielectric block 4a of the sub waveguide portion. The amount of binding can be changed.

As a modification of this embodiment, there is a dielectric block 8 using the same dielectric as the dielectric block 2a of the main waveguide portion and the dielectric block 4a of the sub-waveguide portion. This can be configured by using a body in which the dielectrics of the main waveguide portion 2, the sub-waveguide portion 4 and the intermediate portion are commonly integrated to form a rectangular parallelepiped shape.
In this embodiment, it corresponds to one in which no groove is formed.

In these examples, the coupling amount can be changed by providing the dielectric block 8 with one or more through holes having an appropriate diameter along the longitudinal direction.

Although the microstrip line is used in the above embodiments, the input / output line is not limited to these in the present invention, and various other input / output means can be connected.

Further, in the above embodiments, the electrode film main body 2
a and 4a extend straight in a direction parallel to the side surface of the dielectric block on which the conductor film is not formed, and the electrode film inductance portions 2d and 4d and the electrode film capacitance portion 2 are provided.
e and 4e extend straight in a direction perpendicular to the side surface of the dielectric block on which the conductor film is not formed. However, in the present invention, the electrode film main body portion, the electrode film inductance portion, and the electrode film capacitance portion are not necessarily this. However, the zigzag shape may extend obliquely with respect to the direction parallel or perpendicular to the side surface of the dielectric block on which the conductor film is not formed, and may be curved instead of straight. May be. Further, the electrode film inductance portion and the electrode film capacitance portion may be vertically displaced. Further, the electrode film capacitance portion may extend to the opposite side of the side surface of the dielectric block where the conductor film is not formed, or a plurality of electrode film capacitance portions may extend to both sides.

[0031]

As described above, according to the waveguide type directional coupler of the present invention, the main waveguide portion and the sub-waveguide portion in which the conductor is formed on the side surface except the side surface facing the other side. Are arranged in parallel, and electrode films for input and output are formed on the end faces of the main waveguide portion and the sub-waveguide portion, and the electrode film has a main body portion and an inductance portion and / or a capacitance portion. As a result, downsizing is possible, and the desired characteristics can be easily obtained by appropriately setting the shapes and arrangements of the main waveguide portion and the sub-waveguide portion, and the inclusions between them. In addition, by setting the shape and dimensions of the electrode film, in particular, the inductance part and / or the capacitance part, it is possible to achieve a good adjustment with the input / output impedance only on the coupler side without providing a special matching circuit on the input / output line. It is possible to take.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of a directional coupler according to the present invention.

FIG. 2 is a graph showing a characteristic measurement result of the directional coupler of FIG.

3 is a graph of a characteristic measurement result of the directional coupler of FIG.

FIG. 4 is a schematic perspective view showing a directional coupler of a comparative example.

5 is a graph of characteristic measurement results of the directional coupler of FIG.

FIG. 6 is a schematic perspective view showing a second embodiment of the directional coupler according to the present invention.

7 is a graph of characteristic measurement results of the directional coupler of FIG.

FIG. 8 is a schematic perspective view showing a third embodiment of the directional coupler according to the present invention.

FIG. 9 is a diagram showing an example of a conventional waveguide type directional coupler.

[Explanation of symbols]

 2 Main Waveguide Part 2a Dielectric Block 2a 'Dielectric Block Main Waveguide Part 2b Conductor Film 2c Electrode Film Main Part 2d Electrode Film Inductance Part 2e Electrode Film Capacitance Part 3 Dielectric Substrate 3a Microstrip Line Pattern 4 Sub Waveguide Part 4a Dielectric block 4a 'Dielectric block Sub-waveguide part 4b Conductor film 4c Electrode film main part 4d Electrode film inductance part 4e Electrode film capacitance part 5 Dielectric substrate 5a Micro strip line pattern 6 Dielectric block middle part 6a Groove 7 Dielectric substrate 8 Dielectric block

Front Page Continuation (72) Inventor Mitsunori Takasugi 5 1978, Ou Kogushi, Ube City, Yamaguchi Prefecture Ube Industries Ltd. Inorganic Materials Research Center

Claims (5)

[Claims] 1. A main waveguide portion and a sub-waveguide portion, each of which has a conductor formed on the surface of a dielectric, are arranged in parallel, and the main waveguide portion and the sub-waveguide portion face each other. The conductors are formed on the side surfaces except the side surface of the main waveguide portion and the sub-waveguide portion, and electrode films for input and output are formed on the end surfaces of the main waveguide portion and the sub-waveguide portion. And / or a capacitance section, a dielectric waveguide type directional coupler. 2. A main body part for connecting the electrode film to a conductor on a side surface other than a side surface on which a conductor is not formed and a side surface opposite to the side surface, and a main body part on a side opposite to the side surface on which the conductor is not formed. An inductance portion having one end connected to the side surface and the other end connected to the main body portion, and a capacitance extending from the main body portion toward the side surface where the conductor is not formed and / or the opposite side. The dielectric waveguide type directional coupler according to claim 1, further comprising: 3. The dielectric according to claim 1, wherein the main waveguide section and the sub-waveguide section use separate dielectric blocks, and means are provided for maintaining them at a desired spacing. Waveguide type directional coupler. 4. A dielectric block separate from the main waveguide portion and the sub-waveguide portion is provided between the main waveguide portion and the sub-waveguide portion as a means for maintaining the main waveguide portion and the sub-waveguide portion at a desired distance. The dielectric waveguide type directional coupler according to claim 3, which is sandwiched. 5. The dielectric waveguide type directional coupler according to claim 1, wherein the main waveguide portion and the sub-waveguide portion use different portions of a single dielectric block.