JPS62102A - Directional coupler - Google Patents

Abstract

PURPOSE:To obtain a characteristic at a wide band with high coupling by coupling the 1st strip conductor and the 2nd strip conductor provided in parallel on a dielectric base via other paper-tablet dielectric base. CONSTITUTION:Since the 1st strip conductor 16 and the 2nd strip conductor 17 are connected to the 1st conductor layer 18 and the 2nd conductor layer 19 formed to both side faces of the paper-tablet dielectric base 20 respectively, even when the strip conductor interval is selected larger comparatively, the 1st strip conductor 16 and the 2nd strip conductor 17 are coupled by a high degree of coupling. Thus, it is not required to form the 1st and 2nd strip conductors by the thin film with complicated processing processes, and they are formed by other inexpensive means such as etching of copper foil. Further, no effect given onto the degree of coupling even with a low specific dielectric constant of the dielectric base 15, then the dielectric base with low cost and ease of processing is used.

Description

[Detailed Description of the Invention] [Summary] By coupling a pair of distributed coupling type strip conductors with a length equivalent to a quarter wavelength through a rectangular dielectric substrate, the degree of coupling is high. Moreover, a low-cost directional coupler is provided.

[Industrial application field]

The present invention relates to improvements in distributed coupling type directional couplers using microstrip lines.

A directional coupler for the microwave band or millimeter wave band, which has a desired combination of strip conductors with a length equivalent to a quarter wavelength, is
It is widely used because it has the advantage of being significantly smaller than a directional coupler made of a waveguide.

There are two types of directional couplers using microstrip lines: a direct coupling type and a distributed coupling type. The latter type of distributed combination, which eliminates the disadvantages of , is now more commonly used.

Such a directional coupler is required to have a high degree of coupling and be low in cost.

[Conventional technology]

FIG. 4 is a perspective view of an example of a conventional distributed coupling type directional coupler.

Figure 10 shows an example of a distributed coupling type, which is a small, broadband directional coupler, and is an ink digit type distributed coupler with a high coupling degree of about -3 dB. A lower conductor N is placed on the entire lower surface of the ceramic substrate 5.
6 is formed.

On the top surface of the ceramic substrate 5 are three strip conductors each having a length of approximately 1/4 wavelength. , 9.8 are arranged in parallel in this order and very close to each other (for example, with an interval of 1 to 2 μm).

One end of the strip conductor 7 has a first port, 1
A fourth port 4 is connected to the terminal of the strip conductor 8 located diagonally to the first port 1.

Further, a strip conductor 9 provided between the strip conductor 7 and the strip conductor 8 has a second port 2 connected to the end opposite the first port 1 in parallel to the fourth port 4, and At the other end of the conductor 9, a third port 3 is connected to the end opposite to the fourth port 4 in parallel to the first port 1.

Such a circuit is formed by depositing a nichrome film on the entire surface of the ceramic substrate 5 and a gold film on top thereof, and then by photolithography.

゛Then, the vicinity of the first port 1 and the fourth port 4
The strip conductor 7 and the strip conductor 8 are connected at two locations near the strip conductor 9 by wire bonding or the like with a bridge wire 10 such as a gold ribbon that spans the strip conductor 9.

Since they are coupled as described above, for example, an input signal from the first port l is output from the second port 2 and the fourth port 4, and almost no signal is emitted from the third port 3. It has this direction.

Note that when an input signal is input from the fourth port 4, it is of course outputted from the first port 1 and the third port 3.

[Problem that the invention seeks to solve]

However, in the conventional directional coupler described above, in order to increase the degree of coupling, it is necessary to use a ceramic substrate with a high dielectric constant and to provide strip conductors very close to each other.

For this purpose, an expensive ceramic substrate is used and the strip conductor is formed with a thin film that requires a complicated processing process.
There is a problem that it is high cost.

[Means for solving problems]

In order to solve the above conventional problems, the present invention provides a first strip formed on a dielectric substrate 15, having a first port 1 at one end and a third port 3 at the other end. a second strip conductor 17 formed adjacent to and parallel to the first strip conductor 16 and having a second port 2 formed at one end and a fourth port 4 formed at the other end; , a first conductor layer 18 on one side of the rectangular shape,
A second conductor layer 19 is provided on the other side, the first conductor layer 18 is connected to the first strip conductor 16, and the second conductor layer 1
A rectangular dielectric substrate 20 mounted on the dielectric substrate 15 such that the strip conductors 9 are connected to the second strip conductor 17 respectively
The structure is based on the following.

[Effect]

According to the above means of the present invention, the first strip conductor 16
and the second strip conductor 17 are the first conductor layer 18 . formed on both sides of the rectangular dielectric substrate 20 . Since the first strip conductor 16 is connected to the second conductor layer 19, even if the strip conductor spacing is relatively large, the first strip conductor 16
and the second strip conductor 17 are coupled with a high degree of coupling.

Therefore, for thin films with complicated processing steps, the first There is no need to form the second strip conductor and it can be formed by other inexpensive means, such as etching copper foil. Further, even if the relative dielectric constant of the dielectric substrate 15 is low, it does not affect the degree of coupling, so a low-cost dielectric substrate that is easy to process can be used.

〔Example〕

The present invention will be specifically explained below with reference to illustrated examples. Note that the same reference numerals refer to the same objects throughout the plan.

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is a perspective view of another embodiment, and Fig. 3 is a perspective view of another embodiment of the present invention. A lower conductor layer 6 made of copper foil or the like is provided on the entire lower surface of the dielectric substrate 15, and a conductor layer 6 having a length of approximately λg/ is provided on the upper surface of the dielectric substrate 15.
4 (λg is the effective wavelength determined by the dielectric constant of the rectangular dielectric substrate) first strip conductor 16 is formed. Further, a second strip conductor 17 having the same length is formed close to the first strip conductor 16 (for example, at a distance of 0.5 m) and parallel to the first strip conductor 16 .

A first port 1 is connected at right angles to one end of the first strip conductor 16, and a third port 3 is connected to the other end in a U-shape parallel to the first port 1. Connections are formed.

In addition, a second port facing the terminal provided with the first port 1 is provided.
A second port 2 is connected at right angles to one end of the strip conductor 17, and a fourth port 4 is connected to the other end in a U-shape parallel to the second port 2. ing.

The above circuit pattern can be easily formed by etching a copper foil layer formed on the surface of the dielectric substrate 15.

20 has a desired dielectric constant, a desired width, and a length of λg.
It is an elongated rectangular dielectric substrate of /4.

A first conductor layer 18 is provided on the entire surface of one side surface in the longitudinal direction of the rectangular dielectric substrate 20, and a second conductor layer 19 is provided on the other side surface facing the first conductor layer 18. It is being

The rectangular dielectric substrate 20 has a first conductor layer 18 . Second conductor 1! i19 is perpendicular to the dielectric substrate 15 and parallel to the first strip conductor 16 and the second strip conductor 17,
The first conductor layer 18 is placed on the dielectric substrate 15 so as to straddle the first strip conductor 16, and the second conductor layer 19
are connected to and mounted on the second strip conductor 17 by soldering, respectively.

As described above, the first conductors Ji18. The second conductor layer 19 has a first strip conductor 16 and a second strip conductor 1.
7 are connected to each other, the first strip conductor 16 and the second strip conductor 17 can be coupled with a desired high degree of coupling (for example, -3 dB).

Therefore, for example, an input signal from the first port 1 is output from the third port 3 and the second port 2,
The fourth port 4 has a directionality in which almost no light is emitted.

In addition, 1. Since the spacing between the second strip conductors is relatively large and there is a margin, they can be formed by etching at low cost. Further, even if the relative permittivity of the dielectric substrate 15 is low, it does not affect the degree of coupling, so a dielectric substrate that is easy to process can be used, resulting in low cost.

The ones in FIGS. 2 and 3 are directional couplers that output an input signal from a first port 1 from a second port 2 and a fourth port 4. In FIG.

In FIG. 2, the first strip conductor 16 and the second strip conductor 17, which are formed in parallel to the dielectric substrate 15, are cut at approximately the center to form the first strip conductor 16.
is separated into a strip conductor 16A on the first port 1 side and a strip conductor 16B on the third port 3 side.

Further, the second strip conductor 17 is separated into a strip conductor 17A on the second port 2 side and a strip conductor 17B on the fourth port 4 examples.

Then, the strip conductor 16B and the strip conductor 17A
and are connected by a connecting conductor pattern 31 that diagonally crosses the cut portion.

The first conductor layer 18 and the second conductor layer 19 formed on both sides of the rectangular dielectric substrate 20 are both cut approximately at the center, and the first conductor layer 18 is a conductor on the first port 1 side. Jif
18A and a conductor layer 18B on the third port 3 side,
The second conductor layer 19 is a conductor layer 19A on the second port 2 side.
and a conductor layer 19B on the fourth port 4 side.

The conductor layer 18A and the conductor layer 19B are the dielectric substrate 1
The connection conductor pattern 32 diagonally crosses the center of the upper surface on the side opposite to the side in close contact with the connection conductor pattern 32.

Therefore, for example, an input signal from the first port 1 is output from the second port 2 and the fourth port 4,
The third port 3 has a directionality in which almost no light is emitted.

In FIG. 3, the first conductor layer 18 formed on one side of the rectangular dielectric substrate 20 is cut into a key shape in a side view at approximately the center thereof to form a conductor layer 18A and a conductor layer 18B. It is separated into

Further, the second conductor layer 19 formed on the other surface is cut into a key shape that is opposite to the first conductor layer 18 when viewed from the side, and is separated into a conductor layer 19A and a conductor layer 19B. There is.

The conductor layer 18A and the conductor layer 19B are connected by a through-hole conductor 42 penetrating the rectangular dielectric substrate 20, and the conductor layer 18B and the conductor Jli 19A are connected by a through-hole conductor 41.

The strip conductor on which such a rectangular dielectric substrate 20 is mounted is cut at the center to form the strip conductors 16A, 16B and the strip conductor 1, as shown in FIG.
7A and 17B are formed, and the difference from the one shown in FIG. 2 is that the strip conductor 16B and the strip conductor 17A are not connected by the connection conductor layer 31.

A directional coupler having such a structure also has a directional function similar to that shown in FIGS. 1 and 2.

〔Effect of the invention〕

As explained above, the present invention combines a first strip conductor and a second strip conductor provided in parallel on a dielectric substrate via another rectangular dielectric substrate, It not only has broadband and high coupling characteristics, but also has excellent practical effects such as the dielectric substrate material is inexpensive and easy to process, and the strip conductor is easy to process and low cost. .

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is a perspective view of another embodiment, Fig. 3 is a top view of a rectangular dielectric substrate of another embodiment, and Fig. 4 is a conventional one. FIG. 2 is a perspective view of a directional coupler of FIG. In the figure, ■ is the first port, 2 is the second port, 3 is the third port, 4 is the fourth port, 5 is the ceramic substrate,
6 is the lower conductor layer, 15 is the dielectric substrate, 16 is the first strip conductor, 17 is the second strip conductor, 1 is the first conductor layer, 19 is the second conductor layer, 18A, 18B, 19 ^, 19B is a conductor layer, 20 is a rectangular dielectric substrate, 31.32 is a connection conductor pattern, and 41.42 is a through-hole conductor. 3rd threshold 4th @

Claims (2)

[Claims] (1) A first strip conductor (16) formed on a dielectric substrate and having a first port (1) formed at one end and a third port (3) formed at the other end; a second strip conductor formed adjacent to and parallel to the first strip conductor (16) and having a second port (2) formed at one end and a fourth port (4) formed at the other end; (17), a first conductor layer (18) is provided on one side of the rectangular shape, a second conductor layer (19) is provided on the other side, and the first conductor layer (18) is provided with the first conductor layer (18) on the other side. The first strip conductor (16) has the second conductor layer (19) connected to the second strip conductor (17).
) A directional coupler comprising a rectangular dielectric substrate (20) mounted on the dielectric substrate (15) so as to be connected to the dielectric substrate (15). (2) the first and second strip conductors, and the first
, the second conductor layers are each cut approximately at the center, and the first strip conductor on the first port side connects directly or via the cut conductor layer to the strip conductor on the fourth port side. , the first strip conductor on the third port side is connected to the strip conductor on the second port side directly or through a cut conductor layer. The directional coupler according to item 1.