JP2643825B2 - Microstrip line 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 coupler for coupling two microstrip lines at high frequency, and more particularly, to a common dielectric substrate and ground conductor, and two strip conductors on the surface of the dielectric substrate. The present invention relates to a microstrip line coupler in which two microstrip lines are arranged close to each other with a small gap, and the degree of coupling between the two microstrip lines can be adjusted.

[0002]

2. Description of the Related Art A conventional microstrip line coupler is described in, for example, page 380 of the dictionary of terms used in the telecommunications technology standard terminology (Third Edition) published by Ohm Co., Ltd. on October 30, 1974. It is described in. A conventional method for adjusting the degree of coupling in this type of microstrip line coupler will be described with reference to FIGS. In the figure, reference numerals 2a and 2b denote strip conductors, 3 denotes a dielectric substrate, 4 denotes a ground conductor extending over the entire rear surface of the dielectric substrate 3, A denotes an input signal, and B denotes an output signal.

The strip conductor 2a, the dielectric substrate 3 and the ground conductor 4 form a first microstrip line, and the strip conductor 2b, the dielectric substrate 3 and the ground conductor 4 form a second microstrip line. An input signal A is input to the first microstrip line, is coupled to the second microstrip line to a certain degree, and is output as a signal B from the second microstrip line.

In FIG. 2, reference numeral 5 denotes a strip conductor 2b.
Indicates the region to be resected, and the line XX ′ is the resection line. To cut off the strip conductor 2b along the line XX ', a cutter 7 was used as shown in FIG. As described above, in a region where the strip conductors 2a and 2b are close to each other with a minute gap and are coupled at a high frequency, a part of one of the strip conductors and the side facing the gap is as shown in FIG. By cutting, the width of the gap is widened, so that the degree of coupling between both microstrip lines can be reduced. In the manufacture of high-frequency circuits such as transmitters and receivers, optimal characteristics are often obtained while changing the coupling degree of the microstrip line coupler, and a variable coupling degree type microstrip line coupler is required.

[0005]

In a conventional microstrip line coupler having the structure shown in FIG. 2, the strip conductor 2b is cut with a cutter to adjust the degree of coupling as shown in FIG. This involves a step of cutting the strip conductor with a cutter, so that this step requires skill, and cutting with high dimensional accuracy is not easy for a skilled person, and it is difficult to obtain the required degree of coupling. Was.

As described above, the conventional microstrip line coupler has a problem to be solved with respect to easiness and accuracy in adjusting the degree of coupling.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention provides the following means.

[0008] First and second strip conductors are disposed on a surface of a dielectric substrate in close proximity with a small gap over a predetermined length, and a ground conductor is provided on substantially the entire back surface of the dielectric substrate. And the first strip conductor, the dielectric substrate, and the ground conductor form a first microstrip line, and the second strip conductor, the dielectric substrate, and the ground conductor form a second microstrip line. A microstrip line, wherein the first and second microstrip lines are coupled at a high frequency in the microstrip line coupler.
And a solder resist is applied to the second strip conductor in a plurality of regions at a constant interval, respectively.

The solder resist in each of the regions has a strip shape, and the longitudinal axis of the strip solder resist is orthogonal to the axis of the first and second strip conductors to be applied, respectively. A resist straddles the first or second strip conductor, respectively.
The microstrip line coupler according to the above, wherein both ends of the strip-shaped solder resist reach the dielectric substrate on both sides of the first and second strip conductors.

[0010]

In the above means, the solder resist is applied to the first and second strip conductors independently of each other and in each of the strip conductors in a plurality of regions. Is removed, the dielectric constant between the first and second microstrip lines can be changed stepwise, and the degree of coupling can be adjusted stepwise.

[0011] Since the solder resist is much softer than metal, it can be scraped off by a cutter or the like much more easily than metal. Therefore, the adjustment of the coupling degree in the present invention is easy and does not require skill. Since the solder resist in each area can be applied in the printing process, the dimensions of the area can be determined with high accuracy. Then, the degree of coupling can be set in a stepwise manner by only selecting whether to remove or leave the solder resist in each region. Therefore, the degree of coupling can be arbitrarily selected from a predetermined high accuracy value.

[0012]

Next, the present invention will be described in more detail with reference to examples.

FIG. 1 is a perspective view showing an embodiment of the present invention. In the figure, 10a to 10d and 11a to 11d are dielectric solder resists, 2a and 2b are strip conductors, 3 is a dielectric substrate, 4 is a ground conductor extending all over the back surface of the dielectric substrate 3, A Represents an input signal, and B represents an output signal.

The strip conductor 2a, the dielectric substrate 3 and the ground conductor 4 form a first microstrip line, and the strip conductor 2b, the dielectric substrate 3 and the ground conductor 4 form a second microstrip line. An input signal A is input to the first microstrip line, is coupled to the second microstrip line to a certain degree, and is output as a signal B from the second microstrip line.

The embodiment of FIG. 1 is different from the conventional example of FIG. 3 in that solder resists 10a to 10a, which are dielectrics, are formed on two strip conductors 2a and 2b formed on a dielectric substrate 3.
0d, 11a to 11d. These solder resists are applied in a printing process, and the position, area, and thickness of the applied area are accurate. Solder resist 10a
10d and 11a to 11d also act as dielectrics of the first and second microstrip lines, and thus act as dielectrics of the microstrip line from the input point of signal A to the output point of signal B. Therefore, the degree of coupling between the first and second microstrip lines changes according to the presence or absence of the solder resists 10a to 10d and 11a to 11d. Solder resists 10a to 10d, 11a to 1
If any one of 1d is removed, the effective dielectric constant of the microstrip line from the input point of the signal A to the output point of the signal B decreases, so that the coupling between the first and second microstrip lines is reduced. Degree decreases.

In this embodiment, the solder resists 10a to 10a
By sequentially removing any one of 10d and 11a to 11d, the coupling degree is adjusted stepwise.

[0017]

As described above in detail with reference to the embodiments, in the microstrip line coupler according to the present invention, a solder resist which is much softer than metal is used instead of shaving a strip conductor made of metal such as copper. Since the degree of coupling can be adjusted by shaving, the degree of coupling can be easily adjusted.

Since the solder resist can be applied by printing, the dimensions of the solder resist in each region can be secured with high precision, and the degree of connection can be adjusted with high precision.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional example.

FIG. 3 is a perspective view showing a method of scraping a strip conductor in the conventional example of FIG. 2;

[Explanation of symbols]

 10a to 10d, 11a to 11d Solder resist 2a, 2b Strip conductor 3 Dielectric substrate 4 Ground conductor A Input signal B Output signal 5 Area to be cut in strip conductor 2b 6 Strip conductor cut by cutter 7 Cutter

Claims (2)

(57) [Claims] A first and a second strip conductor are disposed on a surface of a dielectric substrate in close proximity to each other with a minute gap over a predetermined length, and substantially the whole surface is provided on the back surface of the dielectric substrate. A ground conductor extends, and the first strip conductor, the dielectric substrate, and the ground conductor form a first microstrip line, and the second strip conductor, the dielectric substrate, and the ground conductor form a first microstrip line. In a microstrip line coupler forming a second microstrip line and coupling the first and second microstrip lines at high frequency, the first and second microstrip lines are provided in a region facing the small gap.
Characterized in that a solder resist is applied to a plurality of regions on the strip conductor at predetermined intervals, respectively. 2. The solder resist in each of the regions is in the form of a strip, and the longitudinal axis of the strip-shaped solder resist is perpendicular to the axis of the first and second strip conductors to be applied, respectively. Type solder resist
Alternatively, the strip-shaped solder resist extends over the second strip conductor, and both ends of the strip-shaped solder resist reach the dielectric substrate on both sides of the first and second strip conductors. The microstrip line coupler according to claim 1.