JP3972045B2 - Multilayer Lange coupler - Google Patents

Description

  The present invention relates to a Lange coupler, and more particularly to a stacked Lange coupler in which a plurality of coupled lines are formed in two wiring layers.

  Conventionally, a coupler has been widely used as an element for distributing a high-frequency transmission signal. Among them, a Lange coupler is known as a coupler having a broadband characteristic. There are various types of Lange couplers, but each type has a structure in which a plurality of coupled lines are arranged close to each other in parallel (see Patent Document 1). However, in the normal Lange coupler, since each coupling line is arranged in a plane on the substrate, it is necessary to use a bonding wire for partial connection between the coupling lines, which complicates the manufacturing process. There were problems such as.

A so-called “laminated Lange coupler” is known as a Lange coupler that solves such a problem. The laminated type Lange coupler has a structure in which the coupling between the coupled lines is partly three-dimensionalized by forming a plurality of coupled lines in two wiring layers. Thereby, the connection by a bonding wire becomes unnecessary and it becomes possible to simplify a manufacturing process more. As the multilayer Lange coupler, for example, the one disclosed in Patent Document 2 is known.
JP-A-6-232658 Japanese Patent Publication No. 8-28609

  However, since the Lange couplers described in Patent Documents 1 and 2 both have the coupling line exposed on the substrate, the entire high-frequency circuit on which the Lange coupler is mounted is a conductive member to which a ground potential is applied, such as a shield case. When covered, there is a problem that this conductive member greatly affects the characteristics of the coupler, and the actual characteristics deviate greatly from the design values. On the other hand, when it is not covered with a shield case or the like, there arises a problem that the characteristics fluctuate depending on the use environment, for example, the impedance changes when a ground plane such as a metal plate is brought closer to the actual use. Furthermore, since the coupled line is exposed on the substrate, there is a problem that radiation loss is large.

  Moreover, in the multilayer Lange coupler described in Patent Document 2, since the coupled lines are three-dimensionally formed, if the thickness of the insulating layer that three-dimensionally separates the coupled lines is not sufficiently reduced, 1 There is also a problem that a large difference occurs between the distance from the coupling line in the layer to the ground plane and the distance from the coupling line in the second layer to the ground plane, and the symmetry between the coupling lines is impaired.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a multilayer Lange coupler that can obtain characteristics closer to the design value and that has less fluctuation in characteristics depending on the use environment. And

  Another object of the present invention is to provide a stacked Lange coupler having excellent symmetry between coupled lines.

  The multilayer Lange coupler according to the present invention is a first and second coupled line formed in a first wiring layer and parallel to each other, one end of which is commonly connected to the first port and the other end is a second port. First and second coupled lines connected in common to each other and third and fourth coupled lines formed in a second wiring layer different from the first wiring layer and parallel to each other, one end of which The third and fourth coupling lines that are commonly connected to the third port and the other end are commonly connected to the fourth port, and the first and fourth coupling lines sandwiched between the first to fourth coupling lines And a second ground pattern.

  According to the present invention, since the coupling line is sandwiched by the ground pattern, even if the entire high-frequency circuit on which the multilayer Lange coupler is mounted is covered by the shield case, the shield case There is almost no influence on the characteristics, and characteristics close to the design values can be obtained. In addition, even if the ground plane such as a metal plate is brought closer or away during actual use, the impedance hardly changes by this, and it is possible to suppress fluctuations in characteristics according to the use environment. Furthermore, radiation loss is also reduced.

  The lengths of the first to fourth coupled lines are preferably set to a length corresponding to a quarter wavelength of the transmission signal. This makes it possible to obtain good coupling characteristics at the target frequency.

  It is preferable that the distance from the first wiring layer to the first ground pattern and the distance from the second wiring layer to the second ground pattern are substantially equal. According to this, it is possible to obtain high symmetry between the coupled lines, and as a result, it is possible to obtain good coupling characteristics.

  Also, the multilayer Lange coupler according to the present invention has an impedance adjustment pattern in the vicinity of the one end and the other end of the first and second coupling lines and in the vicinity of the one end and the other end of the third and fourth coupling lines. Is preferably formed. According to this, it becomes possible to set the width | variety etc. of a coupling line to the width different from the original design value, As a result, the freedom degree of design increases.

  The impedance adjustment pattern is a distance corresponding to a quarter wavelength of the transmission signal when viewed from the one end and the other end of the first and second coupled lines and the one end and the other end of the third and fourth coupled lines. It is preferable that it is formed in the position within. If the impedance adjustment pattern is formed within this range, a high adjustment effect by the impedance adjustment pattern can be obtained.

  The impedance adjustment pattern is preferably an open stub. According to this, a high impedance adjustment effect can be obtained most easily.

  The length of the open stub is preferably set within a length corresponding to a quarter wavelength of the transmission signal. If the length of the open stub is set to the above length, a high adjustment effect can be obtained without increasing the planar shape of the multilayer Lange coupler more than necessary.

  Thus, according to the present invention, since the coupling line is sandwiched by the ground pattern, even when the entire high-frequency circuit on which the stacked Lange coupler is mounted is covered with a shield case, The shield case has little influence on the characteristics, and it is possible to obtain characteristics close to the design values. In addition, even if the ground plane such as a metal plate is brought closer or away during actual use, the impedance hardly changes by this, and it is possible to suppress fluctuations in characteristics according to the use environment. Furthermore, radiation loss is also reduced.

  In particular, if an impedance adjustment pattern is provided, it is possible to set the width of the coupled line to a width different from the original design value. Therefore, it is difficult to form the coupled line with the original design value due to the limit of manufacturing accuracy. Even a multilayer type Lange coupler can be easily manufactured.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective plan view showing the structure of the multilayer Lange coupler 100 according to the first preferred embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view along the line AA shown in FIG.

  As shown in FIGS. 1 and 2, the multilayer Lange coupler 100 according to the present embodiment includes first and second wiring layers (first wiring layers) formed between an insulating layer 111 and an insulating layer 112. Two coupled lines 101 and 102, and third and fourth coupled lines 103 and 104 formed in a wiring layer (second wiring layer) existing between the insulating layer 112 and the insulating layer 113. Yes. The first to fourth coupling lines 101 to 104 are arranged in parallel to each other, and one of the first and second coupling lines 101 and 102 is commonly connected to the first port 121 and the other. The end is commonly connected to the second port 122. One end of each of the third and fourth coupled lines 103 and 104 is commonly connected to the third port 123, and the other end is commonly connected to the fourth port 124.

  Furthermore, the multilayer Lange coupler 100 according to the present embodiment includes a first ground pattern 131 formed on the surface of the insulating layer 111 and a second ground pattern 132 formed on the surface of the insulating layer 113. Accordingly, the first to fourth coupled lines 101 to 104 have a structure sandwiched between the first and second ground patterns 131 and 132.

  FIG. 3 is a diagram schematically showing a circuit configuration of the multilayer Lange coupler 100 according to the present embodiment.

  As shown in FIG. 3, the first to fourth coupled lines 101 to 104 included in the multilayer Lange coupler 100 include a first coupled line 101, a third coupled line 103, a second coupled line 102, and a fourth coupled line. The coupled lines 104 are arranged in parallel in this order, and adjacent coupled lines are capacitively coupled. The lengths L of the first to fourth coupled lines 101 to 104 are equal to each other, and all of them are set to a length corresponding to a quarter wavelength of the transmission signal. For example, when the transmission signal is 24 GHz and the dielectric constant of the insulating layers 111 to 113 is 6.3, the length L of the coupled line is about 1.2 mm. Further, one of the first to fourth ports 121 to 124 is used as an input port, two are used as output ports, and the remaining one is terminated to, for example, 50Ω.

  The width W of the first to fourth coupled lines 101 to 104 and the interval S between adjacent coupled lines are also set according to the frequency of the transmission signal, etc., but the adjacent coupled lines are formed in different wiring layers. Therefore, the interval S between the coupled lines has a very high degree of freedom. Therefore, this can be realized even with a narrow interval that cannot be formed in a plan view due to the accuracy limit when forming the coupled line.

  As described above, the multilayer Lange coupler 100 according to the present embodiment has a structure in which the first to fourth coupled lines 101 to 104 are sandwiched between the first and second ground patterns 131 and 132. That is, each coupling line 101-104 functions as a strip line instead of a microstrip line. For this reason, even when the entire high-frequency circuit on which the multilayer Lange coupler 100 according to the present embodiment is mounted is covered with a shield case, the shield case has little influence on the characteristics, and a characteristic close to the design value can be obtained. Is possible. In addition, even if the ground plane such as a metal plate is brought closer or away during actual use, the impedance hardly changes by this, and it is possible to suppress fluctuations in characteristics according to the use environment. Furthermore, since the coupled lines 101 to 104 are sandwiched between the first and second ground patterns 131 and 132, the radiation loss is also reduced.

  Here, the distance from the first and second coupled lines 101, 102 formed in the first wiring layer to the first ground pattern 131, and the third and fourth lines formed in the second wiring layer. It is preferable that the distances from the coupled lines 103 and 104 to the second ground pattern 132 are substantially equal. According to this, it is possible to obtain high symmetry between the coupled lines, and as a result, it is possible to obtain good coupling characteristics. This separates the first wiring layer in which the first and second coupling lines 101 and 102 are formed from the second wiring layer in which the third and fourth coupling lines 103 and 104 are formed. This means that a sufficient film thickness of the insulating layer 112 can be ensured, whereby a sufficient manufacturing margin can be ensured and the reliability of the product can be improved.

  Next, a second preferred embodiment of the present invention will be described.

  FIG. 4 is a perspective plan view showing the structure of the multilayer Lange coupler 200 according to the preferred second embodiment of the present invention. The cross section along the line AA in FIG. 4 is exactly the same as the structure shown in FIG.

  As shown in FIG. 4, the multilayer Lange coupler 200 according to the present embodiment includes the vicinity of the branch region of the first and second coupled lines 101 and 102 and the vicinity of the branch region of the third and fourth coupled lines 103 and 104. In addition, it differs from the multilayer Lange coupler 100 according to the above embodiment in that open stub type impedance adjustment patterns 201 to 204 are formed. Since the other points are the same as those of the multilayer Lange coupler 100 according to the above-described embodiment, the same components are denoted by the same reference numerals, and redundant description is omitted.

  The branch region of the first and second coupled lines 101 and 102 refers to one end and the other end of the first and second coupled lines 101 and 102, and impedance adjustment patterns 201 and 202 are formed in the vicinity thereof. . Similarly, the branch regions of the third and fourth coupled lines 103 and 104 indicate one end and the other end of the third and fourth coupled lines 103 and 104, and the impedance adjustment patterns 203 and 204 are formed in the vicinity thereof. Has been.

  The impedance adjustment patterns 201 to 204 play a role of adjusting the impedances of the coupling lines 101 to 104 viewed from the first to fourth ports 121 to 124. That is, as the frequency of the transmission signal increases, the width W of the coupled lines 101 to 104 needs to be reduced. However, since the width W of the coupled lines 101 to 104 is limited by the accuracy limit at the time of manufacture, the width is less than a predetermined width. It cannot be thinned. For this reason, when the target frequency is very high, there may be a case where a desired impedance cannot be obtained. In particular, when a structure in which the top and bottom of the first to fourth coupled lines are sandwiched between ground patterns as in the multilayer Lange coupler according to the present invention, the coupled line width is larger than when the ground pattern is formed only on one surface. Since it is necessary to make the material thinner, it is considered that it is easily affected by the accuracy limit during production.

  Even in such a case, if the width W of the coupling lines 101 to 104 is set to be wider than the theoretical value, and the characteristic deviation due to this is compensated by the impedance adjustment patterns 201 to 204, the target frequency is obtained. Thus, a desired impedance can be obtained. As an example, when the transmission signal is 24 GHz and the relative permittivity of the insulating layers 111 to 113 is 6.3, in order to obtain good characteristics when the impedance adjustment patterns 201 to 204 are not provided (see FIG. 1). Although it is necessary to set the width W of the coupled lines 101 to 104 to about 16 μm, when the impedance adjustment patterns 201 to 204 are provided (see FIG. 4), the width W of the coupled lines 101 to 104 is set to about 60 μm. By doing so, good characteristics can be obtained. As a result, the level of microfabrication required during manufacturing is relaxed, and thus manufacturing costs can be reduced.

  The impedance adjustment patterns 201 to 204 are preferably formed at positions within a distance corresponding to a quarter wavelength of the transmission signal as viewed from the branch region. If the impedance adjustment patterns 201 to 204 are formed within this range, a high adjustment effect by the impedance adjustment patterns 201 to 204 can be obtained.

  In the present embodiment, open stub type patterns are used as the impedance adjustment patterns 201 to 204. This is because a high adjustment effect is most easily obtained. The length P of the open stub is preferably set within a length corresponding to a quarter wavelength of the transmission signal. When the length P of the open stub is set to the above length, a high adjustment effect can be obtained without increasing the planar shape of the multilayer Lange coupler 200 more than necessary.

  However, in the present invention, it is not essential to use an open stub type pattern as the impedance adjustment patterns 201 to 204. For example, a short stub type pattern may be used as shown in FIG. As shown in FIG. 7, a part of the ports 121 to 124 may be wide, or a part of the ports 121 to 124 may be narrow.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

1 is a perspective plan view showing the structure of a multilayer Lange coupler 100 according to a preferred first embodiment of the present invention. It is a schematic sectional drawing along the AA line shown in FIG. 1 is a diagram schematically showing a circuit configuration of a multilayer Lange coupler 100 according to the present embodiment. FIG. 6 is a perspective plan view showing the structure of a multilayer Lange coupler 200 according to a preferred second embodiment of the present invention. It is a partial top view which shows the example which made the impedance adjustment patterns 201-204 the pattern of a short stub type. It is a partial top view which shows the example which made the impedance adjustment patterns 201-204 the wide pattern. It is a partial top view which shows the example which used the impedance adjustment patterns 201-204 as the narrow pattern.

Explanation of symbols

100,200 Multilayer Langhe couplers 101-104 Coupling lines 111-113 Insulating layers 121-124 Ports 131, 132 Ground patterns 201-204 Impedance adjustment pattern L Length of coupling line W Coupling line width S Pitch between coupling lines Stub length

Claims (3)

First and second coupled lines formed in the first wiring layer and parallel to each other, one end commonly connected to the first port and the other end commonly connected to the second port A second coupled line;
Third and fourth coupled lines formed in a second wiring layer different from the first wiring layer and parallel to each other, one end of which is commonly connected to the third port and the other end is a fourth wiring line Third and fourth coupled lines commonly connected to the port;
A multilayer Lange coupler comprising: first and second ground patterns formed so as to sandwich the first to fourth coupled lines.   Impedance adjustment patterns are formed in the vicinity of the one end and the other end of the first and second coupling lines, and in the vicinity of the one end and the other end of the third and fourth coupling lines. The multilayer Lange coupler according to claim 1. The impedance adjustment pattern has a quarter wavelength of the transmission signal when viewed from the one end and the other end of the first and second coupled lines and the one end and the other end of the third and fourth coupled lines. The multilayer Lange coupler according to claim 2, wherein the stacked Lange coupler is formed at a position within a corresponding distance.

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