JP2768411B2 - Dielectric waveguide directional coupler - Google Patents

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 formed by forming a waveguide by coating a part of an outer surface of a dielectric material such as ceramics with a conductor.

[0002]

2. Description of the Related Art FIGS. 9A and 9B show an example of a conventional waveguide type directional coupler. FIG. 9A is an external view and FIG. 9B is a sectional view. The main waveguide and the sub-waveguide are joined together as shown in the figure, and an opening A and an opening B are formed at the joint at a distance of 1/4 of the waveguide wavelength λg of the waveguide. ing. Most of the waves incident from the main waveguide opening 11 pass through the main waveguide opening 13, but part of the waves pass through the openings A and B and propagate into the sub-waveguide. Among the waves passing through the two openings A and B, the wave propagating rightward toward the sub-waveguide opening 14 has no propagation path difference to the right from the position B ′ corresponding to the opening B. Therefore, they have the same phase, and add to arrive at the sub-waveguide opening 14. In contrast,
The wave propagating leftward toward the sub-waveguide opening 12 has a half-wavelength propagation path difference to the left of the position A ′ corresponding to the aperture A, and is out of phase. It does not reach the waveguide opening 12.

[0003] In such a conventional waveguide type directional coupler, there is a problem that the waveguide size becomes large in the case of a low frequency wave, which is not preferable in practical use. For example,
At 1.5 GHz, the size of the waveguide is 165 × 82.
5 mm, and the length of 1/4 of the guide wavelength λg (the distance between the openings A and B) is 250 mm. Further, the characteristics of the conventional waveguide type directional coupler cannot be changed as necessary.

Therefore, a dielectric waveguide type directional coupler in which a conductor film is formed on the surface of a dielectric has been proposed in order to reduce the size. However, in the dielectric waveguide type directional coupler proposed in the past, the shape of the electrode for input and output was a simple shape. It was necessary to form a matching circuit.

The present invention has been made in view of the above-mentioned conventional technology, and provides a waveguide type directional coupler which can be reduced in size and easily obtain desired characteristics including matching with input / output impedance. It is intended to do so.

[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 main waveguide portion and the sub-waveguide portion have the conductor formed on a side surface excluding the side surface facing the other, and further have an end face with the main waveguide portion and the sub-waveguide portion. A dielectric waveguide type directional coupler is provided, wherein an electrode film for output is formed, and the electrode film has an inductance part and a capacitance part.

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

Further, in the present invention, there is an embodiment in which the main waveguide portion and the sub-waveguide portion use separate dielectric blocks and have means for maintaining them at desired intervals. . Here, as means for maintaining the main waveguide portion and the sub-waveguide portion at a desired interval, another dielectric block is interposed between the main waveguide portion and the sub-waveguide portion. Can be.

Further, in the present invention, there is an embodiment in which the main waveguide portion and the sub waveguide portion use different portions of a single dielectric block.

[0010]

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 a directional coupler according to the present invention. In the figure, reference numeral 2 denotes a main waveguide portion, and 4 denotes a sub-waveguide portion, which are arranged in parallel with rectangular parallelepiped blocks (length L, width W, height H). The main waveguide portion 2 has conductor films (e.g., three side surfaces) excluding one side surface facing the sub waveguide portion 4 among four side surfaces extending in the longitudinal direction of the rectangular parallelepiped high dielectric constant dielectric block 2a. (A silver film) 2b, and an electrode film main portion 2c is provided on both end surfaces in the longitudinal direction so as to be electrically connected to the conductor film 2b. The electrode film main portion 2c has a linear shape extending in parallel (ie, in the vertical direction) with a side surface facing the sub-waveguide portion 4 (ie, a side surface on which the conductor film is not formed). However, the lower edge of the electrode film main portion 2c is not conductive and is separated from the conductor film provided on the lower surface of the dielectric block 2a. That is, there is a region on the lower surface of the dielectric block 2a where the conductor film 2b is not formed partially for this separation. Further, the conductor film provided on the side opposite to the side facing the sub-waveguide portion 4 and the electrode film main portion 2c are connected to the end face of the dielectric block where the electrode film main portion 2c is formed. For example, an electrode film inductance portion 2d extending in the horizontal direction is provided. Further, the electrode film main portion 2c is provided on the end face of the dielectric block where the electrode film main portion 2c is formed.
An electrode film capacitance portion 2e extending in the horizontal direction from the side to the side surface where the conductor film is not formed is provided. The electrode film main 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 section 2 has a dielectric block 2a.
It is mounted on a dielectric substrate 3 having a lower dielectric constant. On the surface of the dielectric substrate 3, an input / output microstrip line pattern (for example, a copper film) 3a for conducting with the electrode film main portion 2c is formed, and on the back surface, a ground conductor film (not shown). Are formed.

The side of the sub-waveguide portion 4 is the same as that of 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 portion, 4d is an electrode film inductance portion, and 4e is an electrode film capacitance portion. Reference numeral 5 denotes a dielectric substrate, and reference numeral 5a denotes a microstrip line pattern. The dielectric substrate 3 and the dielectric substrate 5 are formed by dielectric blocks 2a and 4a.
Are arranged using gap adjustment means (not shown) so that the opposing surfaces are parallel with a gap (gap) G.

The dimensions L, W, H and G can be set appropriately according to desired characteristics. In particular, the dimension G can be changed by the gap adjusting means. Further, the electrode film main portions 2c and 4c, the electrode film inductance portion 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 input / output impedance.

In this embodiment, the dielectric blocks 2a,
Relative dielectric constant epsilon _r is used as about 93 as 4a, the dielectric constant epsilon _r is used as approximately 4 as the dielectric substrate 3, 5, L
= 10 mm, W = 5 mm, H = 5 mm, G = 1 mm, and the electrode film main portions 2c, 4c having a width of 1 mm are arranged at the center in the left-right direction, and the electrode film inductance portions 2d,
4d is placed at the center in the vertical direction with a width of 1 mm,
FIGS. 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.

FIG. 2 shows the ends of two line patterns 3a on the side of the main waveguide portion 2 as shown in FIG.
The signal power is input from P1, with the ends of the two line patterns 5a on the sub-waveguide portion 4 side as P3 and P4,
Powers S ₂₁ and S output from P2, P3 and P4 respectively
_31, is reflected in S ₄₁ and P1 shows the results of measuring the power S ₁₁ outputted. 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 substantially output to P3, and the function of the directional coupler is exhibited. The same applies when signal power is input from P2, P3, and P4.

By changing the dimensions L and G, the amount of coupling (S ₄₁ ) can be changed, and a directional coupler having desired characteristics can be manufactured.

FIG. 3 is a Smith chart of the reflected power of P1 and P2. Note that 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 denoted by the same reference numerals. This comparative example is different from the above-described embodiment of the present invention only in the configuration of the electrode film, and includes only 1.6 mm wide main portions 2c and 4c adjacent to the side surface of the dielectric block 2 where the conductive film is not formed. Otherwise, it 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 power of P1 and P2 in this comparative example. Note that no matching circuit is provided in the microstrip line pattern.

As can be seen from a 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 portion, the inductance portion and the capacitance portion, there is no need to provide a matching circuit in the microstrip line pattern. While the matching with the input / output impedance is good, the electrode film of the comparative example is composed of only the main part, so that the matching with the input / output impedance is required when the matching circuit is not provided in the microstrip line pattern. It has not been taken.

FIG. 6 is a schematic perspective view showing a second embodiment of the directional coupler according to the present invention. In the figure, reference numeral 2 denotes a main waveguide portion, and 4 denotes a sub-waveguide portion, which have a rectangular parallelepiped shape 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 as a whole having a width W, a part of which forms a main waveguide part, a part of which forms a sub-waveguide part, and an intermediate part 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 above the intermediate portion. The main waveguide section 2 and the sub-waveguide section 4 are mounted on a common dielectric substrate 7. 3a and 5a are microstrip line patterns.

In the present embodiment, used as the dielectric constant epsilon _r of about 93 as the dielectric block, used as dielectric constant epsilon _r of about 4 as the dielectric substrate 7, L = 10 mm, W
= 12 mm, H = 5 mm, G = 3.0 mm, D = 1.8
FIG. 7 shows the characteristic measurement results when mm is set. 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
Although the signal is output to P2 and P4 in the bandwidth of MHz but is not substantially output to P3, it can be seen that the function of the directional coupler is exhibited. The same applies when signal power is input from P2, P3, and P4.

In this embodiment, the coupling amount can be changed by appropriately setting the shape and size of the groove 6a. For example, when L was 19 mm, the directional coupling function could be exhibited at a bandwidth of about 1000 MHz.

By using an integral dielectric block as in this embodiment, a directional coupler with 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. In this figure, the dielectric substrate and the microstrip line pattern are not shown, but 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 and the dielectric block 4a of the sub-waveguide. That is, the dielectric block 8 keeps the distance between the main waveguide portion 2 and the sub-waveguide portion 4 constant. In the present 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 and the dielectric block 4a of the sub-waveguide. This can be configured by using a main waveguide portion 2, a sub-waveguide portion 4, and a dielectric material of the intermediate portion that are integrated and formed into a rectangular parallelepiped shape.
Corresponds to the case where no groove is formed in the embodiment.

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

In the above embodiment, a microstrip line is used. However, in the present invention, the input / output lines are not limited to these, and other various input / output means can be connected.

Further, in the above embodiment, the electrode film main portion 2
a, 4a extend straight in a direction parallel to the side surface of the dielectric block on which the conductor film is not formed, and have electrode film inductance portions 2d, 4d and electrode film capacitance portions 2d.
Although 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, in the present invention, these electrode film main portion, electrode film inductance portion and electrode film capacitance portion are not necessarily provided. It is not limited thereto, and may extend obliquely to a direction parallel or perpendicular to the side of the dielectric block where the conductor film is not formed, may be not straight but may be bent, and may be zigzag. You may. Further, the electrode film inductance portion and the electrode film capacitance portion may be vertically displaced. Further, the electrode film capacitance portion may extend in a direction opposite to the side surface of the dielectric block where the conductor film is not formed, or a plurality of the electrode film capacitance portions may extend in both directions.

[0031]

As described above, according to the waveguide type directional coupler of the present invention, the main waveguide portion and the sub waveguide portion having the conductor formed on the side surface except the side surface facing the other side. Are arranged in parallel, and furthermore, an electrode film for input and output is formed on an end face of the main waveguide portion and the sub waveguide portion, and the electrode film has a main portion, an inductance portion, and a capacitance portion. 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, as well as miniaturizing. By appropriately setting the shapes and dimensions of the electrode film, particularly the inductance and capacitance portions, it is possible to achieve good matching with the input / output impedance only on the coupler side without providing a special matching circuit on the input / output line. That.

[Brief description of the 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 characteristics measurement results of the directional coupler of FIG. 1;

FIG. 3 is a graph showing characteristics measurement results of the directional coupler shown in FIG. 1;

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

FIG. 5 is a graph showing characteristics measurement results of the directional coupler shown in FIG. 4;

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

FIG. 7 is a graph showing characteristics measurement results of the directional coupler of FIG. 6;

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]

 Reference Signs List 2 Main waveguide portion 2a Dielectric block 2a 'Dielectric block main waveguide portion 2b Conductive film 2c Electrode film main portion 2d Electrode film inductance portion 2e Electrode film capacitance portion 3 Dielectric substrate 3a Microstrip line pattern 4 Sub waveguide Part 4a Dielectric block 4a 'Dielectric block sub-waveguide part 4b Conductive film 4c Electrode film main part 4d Electrode film inductance part 4e Electrode film capacitance part 5 Dielectric substrate 5a Microstrip line pattern 6 Dielectric block intermediate part 6a Groove 7 Dielectric substrate 8 Dielectric block

Continuation of front page (56) References JP-A-4-286202 (JP, A) JP-A-3-270501 (JP, A) JP-A-61-77403 (JP, A) US Patent 4,242,401 (US, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01P 5/18 H01P 5/107

Claims (6)

(57) [Claims] 1. A main waveguide portion and a sub waveguide portion each having a conductor formed on a surface of a dielectric are arranged in parallel, and the main waveguide portion and the sub waveguide portion face each other. The conductor is formed on a side surface except for a side surface to be formed, and further, an electrode film for input and output is formed on an end surface of the main waveguide portion and the sub waveguide portion, and the electrode film is formed of a conductor. A main body portion to be connected to a conductor on a side surface other than the side surface not formed and the side surface opposite to the side surface, one end is connected to the side surface opposite to the side surface on which the conductor is not formed, and the other end is A dielectric waveguide type having an inductance portion connected to the main portion, and a capacitance portion extending from the main portion toward a side surface on which the conductor is not formed. Directional coupler. 2. A main waveguide portion and a sub-waveguide portion each having a conductor formed on a surface of a dielectric are arranged in parallel, and the main waveguide portion and the sub-waveguide portion face each other. The conductor is formed on a side surface except for a side surface to be formed, and further, an electrode film for input and output is formed on an end surface of the main waveguide portion and the sub waveguide portion, and the electrode film is formed of a conductor. A main body portion to be connected to a conductor on a side surface other than the side surface not formed and the side surface opposite to the side surface, one end is connected to the side surface opposite to the side surface on which the conductor is not formed, and the other end is A dielectric waveguide, comprising: an inductance portion connected to the main portion; and a capacitance portion extending from the main portion to a side opposite to a side surface on which the conductor is not formed. Tube type directional coupler. 3. A main waveguide portion and a sub-waveguide portion each having a conductor formed on a surface of a dielectric are arranged in parallel, and the main waveguide portion and the sub-waveguide portion face each other. The conductor is formed on a side surface except for a side surface to be formed, and further, an electrode film for input and output is formed on an end surface of the main waveguide portion and the sub waveguide portion, and the electrode film is formed of a conductor. A main body portion to be connected to a conductor on a side surface other than the side surface not formed and the side surface opposite to the side surface, one end is connected to the side surface opposite to the side surface on which the conductor is not formed, and the other end is An inductance portion connected to the main portion, and a capacitance portion extending from the main portion toward the side where the conductor is not formed and toward the opposite side, Dielectric waveguide type directional coupler. 4. The apparatus according to claim 1, wherein said main waveguide section and said sub-waveguide section use separate dielectric blocks, and are provided with means for maintaining them at desired intervals. 3. The dielectric waveguide type directional coupler according to 1.). 5. As another means for maintaining the main waveguide portion and the sub-waveguide portion at a desired distance, another dielectric block is provided between the main waveguide portion and the sub-waveguide portion. 5. The directional coupler according to claim 4, wherein the directional coupler is sandwiched. 6. The dielectric waveguide type according to claim 1, wherein the main waveguide portion and the sub waveguide portion use different portions of a single dielectric block. Directional coupler.