JP2002135014A - Branch circuit, high-pass filter, and branching filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a branch circuit which can solve the problem raised by the conventional branch circuit used in a high-frequency circuit that the parasitic reactance in a connection becomes larger and the passing characteristic, etc., of the high-frequency circuit is deteriorated when the widths of connected lines become broader, because three or more lines are simply connected to each other in the connection. SOLUTION: In the branch circuit, transmission lines 1, 2, and 3 which are connected to each other in the connection around the branch point 4 are respectively provided near the connection with narrow-line sections 5, 6, and 7 having line widths narrower than the widths of the narrowest portions of the lines 1, 2, and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch circuit formed by connecting a plurality of transmission lines for transmitting a high frequency signal in a microwave band or a millimeter wave band, and a branch circuit having the branch circuit. The present invention relates to a high-pass filter and a duplexer.

[0002]

2. Description of the Related Art FIG.
2000 IEICE General Conference C-2-98, "Microwave circuit pattern generation using genetic algorithm"
FIG. 4 is a circuit pattern diagram illustrating a configuration of a conventional bandpass filter in the high-frequency circuit described in FIG. In FIG.
101 is a transmission line, 102 and 103 are open-end stubs that branch off from the transmission line 101 and 104 is a transmission line 1
This is a T-type branch circuit composed of a stub 103 and an open-end stub 103. As shown in FIG.
When connecting the stub 103 with the open end, the T-shaped branch circuit 104 is configured by simply connecting lines gathered from three directions.

[0003]

Since the conventional branch circuit relating to the high-frequency line is constructed as described above, three or more lines are simply connected and the line width of the connected line is large. However, there is a problem in that the parasitic reactance generated in the connection portion is increased to deteriorate the pass characteristics and the reflection characteristics of the high-frequency circuit and to narrow the band of the high-frequency circuit.

Further, when the line width of a line to be connected is large, a connection point to be specified as a portion where a plurality of lines intersect becomes unclear, and the design accuracy in circuit design decreases. there were. Although it is possible to evaluate and analyze the above-mentioned parasitic reactance using the simulation means related to the electromagnetic field analysis, the simulation related to the electromagnetic field analysis requires a great amount of time, and the microwave band and the millimeter wave In the high frequency band of the band, sufficient calculation accuracy cannot always be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and reduces the parasitic reactance at a connection portion of a branch circuit formed by connecting three or more lines, thereby improving the transmission characteristic and the transmission characteristic. It is an object of the present invention to obtain a branch circuit having improved reflection characteristics and the like, and a high-pass filter and a duplexer including the branch circuit.

Further, the present invention clarifies a connection point in a branch circuit formed by connecting three or more lines, and has a branch circuit capable of improving design accuracy in circuit design, and a branch circuit having the branch circuit. It is an object of the present invention to obtain a high-pass filter and a duplexer configured as follows.

[0007]

A branch circuit according to the present invention includes three or more transmission lines connected to each other at a connection portion, and at least one of the transmission lines is connected to the connection portion. A thin line portion in which the line width is narrower than the line width at a portion separated from the connection portion in the vicinity is provided.

In the branch circuit according to the present invention, each of the transmission lines connected to each other at the connection portion has a thin line portion having a line width smaller than the line width of the transmission line having the smallest line width at a portion separated from the connection portion. In the vicinity of the connection portion.

A branch circuit according to the present invention includes three or more transmission lines connected to each other at a connection part, and a stub for reactance adjustment connected to the connection part.

A branch circuit according to the present invention includes three or more transmission lines connected to each other at a connection part, and at least one of the transmission lines has a narrow line width near the connection part. A thin wire portion is provided, and a stub for reactance adjustment connected to the connection portion is further provided.

The high-pass filter according to the present invention has a first
, A second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, and a connection portion between the first transmission line and the second transmission line. A third transmission line to which one end is connected and a grounding element is connected to the other end;
At least one of the transmission line, the second transmission line, and the third transmission line is provided with a thin line portion having a narrow line width in the vicinity of the connection portion. It has one.

The high-pass filter according to the present invention has a first
, A second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, and a connection portion between the first transmission line and the second transmission line. A filter unit including a third transmission line to which one end is connected and a grounding element is connected to the other end, and a reactance adjusting stub connected to the connection portion, as a cascade-connected structural unit It has at least one.

[0013] A duplexer according to the present invention includes a first transmission line, a second transmission line, and a third transmission line connected to each other at a connection portion, and a side opposite to the connection portion of the first transmission line. A high-pass filter connected to the end of the second transmission line, a low-pass filter connected to the end opposite to the connection of the second transmission line, and an opposite side to the connection of the third transmission line. And at least one of the first transmission line, the second transmission line, and the third transmission line has a line width in the vicinity of the connection portion. It is provided with a narrow line portion that becomes narrower.

[0014] The duplexer according to the present invention includes a first transmission line, a second transmission line, and a third transmission line connected to each other at a connection portion, and a side opposite to the connection portion of the first transmission line. A high-pass filter connected to the end of the second transmission line, a low-pass filter connected to the end opposite to the connection of the second transmission line, and an opposite side to the connection of the third transmission line. And a stub for reactance adjustment connected to the connection portion.

The duplexer according to the present invention includes a fourth transmission line, a fifth transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, A sixth transmission line having one end connected to the connection portion in the filter between the transmission line and the fifth transmission line, and a grounding element connected to the other end;
Cascade connection of a high-pass filter, in which at least one of the transmission line, the fifth transmission line, and the sixth transmission line has a thin line portion whose line width becomes narrow in the vicinity of the connection portion in the filter. It has at least one structural unit related to the structure.

The duplexer according to the present invention includes: a fourth transmission line; a fifth transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion; One end is connected to the connection part in the filter between the transmission line and the fifth transmission line, and the other end is connected to the sixth transmission line in which the grounding element is connected, and the connection part in the filter. At least one filter unit including a reactance adjusting stub is provided as a structural unit related to a cascade connection structure of a high-pass filter.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a circuit diagram showing a configuration of the branch circuit according to the first embodiment of the present invention. In FIG.
Reference numerals 1, 2, and 3 denote transmission lines, and reference numeral 4 denotes a branch point which is regarded as a design connection center at a connection portion connecting the transmission lines 1, 2, and 3 so as to form a branch circuit.
Is a thin line portion defined as a narrow line width portion near the branch point 4 in the transmission line 1; 6 is a thin line portion defined as a narrow line width portion near the branch point 4 in the transmission line 2;
Reference numeral 7 denotes a thin line portion defined as a narrow line width portion near the branch point 4 in the transmission line 3.

Next, the operation will be described. Transmission line 1,
In connecting the transmission lines 2 and 3 to form a branch circuit, the transmission lines 1 and
The line widths of the transmission line 2 and the transmission line 3 are reduced to form the thin line portion 5, the thin line portion 6, and the thin line portion 7, respectively. Since the line width of the transmission line near the branch point 4 is reduced, the area of the connection around the branch 4 is reduced, and the parasitic reactance generated at the connection is reduced.

As described above, according to the first embodiment, the transmission line 1, which is connected to form a branch circuit,
Since the transmission line 2 and the transmission line 3 are configured to include the thin line portion 5, the thin line portion 6, and the thin line portion 7 each having a narrow line width near the connection portion around the branch point 4, the parasitic reactance generated in the connection portion is reduced. This is effective in reducing the deterioration of the pass characteristics and the reflection characteristics of the high-frequency circuit.

Further, the transmission lines 1, 2, 3, 3 gathering at the connection portion
By reducing the line width of the line, the area of the connection portion is reduced, the error related to the positioning of the branch point regarded as the connection center in the design can be reduced, and the design accuracy in circuit design can be improved. It has the effect of being able to.

Embodiment 2 FIG. FIG. 2 is a circuit diagram showing a configuration of a branch circuit according to a second embodiment of the present invention. FIG.
, 11, 12, and 13 are transmission lines, 14 is a branch point which is regarded as a design connection center in a connection portion connecting the transmission lines 11, 12 and 13 so as to form a branch circuit, and 15 is a branch point. One end is a branch point 14
The transmission line connected to the surrounding connection portion, 16 is the transmission line 1
Reference numeral 17 denotes a grounding element such as a via hole connected to the other end of the reference numeral 5, and a short-circuiting stub (reactance adjusting stub) including a transmission line 15 and a grounding element 16.

Next, the operation will be described. Transmission line 1
1. If the value of the parasitic reactance generated at the connection part around the branch point 14 of the branch circuit formed by connecting the transmission line 12 and the transmission line 13 is known, an appropriate length according to the parasitic reactance is used. Tip short-circuit stub 17 having
Is connected to the branch circuit at the connection portion, the parasitic reactance generated at the connection portion can be reduced.

As described above, according to the second embodiment, the short-circuited stub 17 is connected to the connection part of the branch circuit formed by connecting the transmission lines 11, 12, and 13. Because of the configuration, the tip short-circuit stub 1
By adjusting 7 to an appropriate length according to the parasitic reactance generated at the connection portion, the parasitic reactance generated at the connection portion can be reduced, so that the deterioration of the pass characteristics and the reflection characteristics of the high-frequency circuit can be reduced. This has the effect.

In the second embodiment, the short-circuit stub 1 is used as a reactance adjusting stub for reducing the parasitic reactance at the connection portion of the branch circuit.
Although the configuration using No. 7 has been described, depending on the connection form of each transmission line at the connection portion of the branch circuit, even if an open-end stub provided as the transmission line 15 without the grounding element 16 is used, the parasitic portion at the connection portion of the branch circuit can be used. In some cases, the reactance can be reduced, and the same operation and effect as when the short-circuit stub is used can be obtained.

Embodiment 3 FIG. 3 is a circuit diagram showing a configuration of a branch circuit according to a third embodiment of the present invention. FIG.
, 22, 23 are transmission lines, and 24 is a branch point which is regarded as a design connection center in a connection portion connecting the transmission lines 21, 22 and 23 so as to form a branch circuit. Reference numerals 26 and 27 denote thin line portions defined as narrow line width portions near the branch point 24 in the transmission lines 21, 22 and 23, respectively, and reference numeral 28 denotes a transmission line having one end connected to a connection portion around the branch point 24. , 2
Reference numeral 9 denotes a grounding element such as a via hole connected to the other end of the transmission line 28, and reference numeral 30 denotes a tip short-circuit stub (reactance adjustment stub) including the transmission line 28 and the grounding element 29.

Next, the operation will be described. Transmission line 2
1. In forming a branch circuit by connecting the transmission line 22 and the transmission line 23, the line widths of the transmission line 21, the transmission line 22 and the transmission line 23 near the branch point 24 are reduced, and the thin line portion 25 and the thin line, respectively. The portion 26 and the thin line portion 27 are formed. Since the line width of the transmission line near the branch point 24 is reduced, the area of the connection around the branch 24 is reduced, and the parasitic reactance generated at the connection is reduced. If the value of the parasitic reactance generated at the connection portion is known, the tip short-circuit stub 3 having an appropriate length according to the parasitic reactance is used.
By connecting 0 to the branch circuit at the connection, the parasitic reactance generated at the connection can be further reduced.

As described above, according to the third embodiment, the transmission line 2 connected to form a branch circuit
1. Each of the transmission line 22 and the transmission line 23 includes a thin line portion 25, a thin line portion 26, and a thin line portion 27 each having a narrow line width near a connection point around the branch point 24.
Since the tip short-circuit stub 30 is connected to the connection portion of the branch circuit, the parasitic reactance generated at the connection portion is reduced by reducing the line width near the connection portion, and the parasitic reactance corresponding to the reduced parasitic reactance is reduced. By adding a tip short-circuit stub having a length, the parasitic reactance generated at the connection part can be made smaller,
There is an effect that deterioration of the pass characteristics and the reflection characteristics of the high frequency circuit can be further reduced.

In the third embodiment, as in the second embodiment, it is possible to use an open-end stub provided as the transmission line 28 without the grounding element 29 as a reactance adjusting stub. The same operation and effect as when the short-circuit stub is used can be obtained.

Embodiment 4 FIG. 4 is a circuit diagram showing a configuration of a filter unit of a high-pass filter according to Embodiment 4 of the present invention, and a cross-sectional view showing a partial circuit portion of the filter unit. In FIG. 4, 31 is a transmission line (first transmission line), 32 is a transmission line (second transmission line), 33 is a transmission line (third transmission line), and 34 is a transmission circuit to constitute a branch circuit. The branch points 35, 36, and 37, which are regarded as the design connection centers at the connection points connecting the lines 31, the transmission lines 32, and the transmission lines 33, have the line widths near the branch point 34 in the transmission lines 31, 32, and 33, respectively. A thin line portion defined as a narrow portion, 38 is a parallel plate capacitor (capacitor) disposed on the transmission line 32, and 39 is a grounding hole such as a via hole connected to an end of the transmission line 33 opposite to the connection portion. The element 40 is a short-circuited stub consisting of the transmission line 33 and the element 39 for grounding. Note that the transmission line 32 is a parallel plate capacitor 3
8 and a line portion 32 extending from the other electrode portion of the parallel plate capacitor 38.
b.

The filter unit of the high-pass filter shown in FIG. 4 includes a main line composed of a transmission line 31 and a transmission line 32, a capacitor connected in series to the main line provided as a parallel plate capacitor 38, and a short circuit at the tip. It has an inductor connected in parallel to a main line provided as a stub 40. The high-pass filter is configured by cascade-connecting the filter units with the filter unit having such a circuit configuration as a constituent unit.

Next, the operation will be described. Since a parasitic reactance exists in the connection part around the branch point 34, an error occurs in the reactance adjustment based on the capacitor connected in series with the main line and the inductor connected in parallel with the main line. Accordingly, the line widths of the transmission lines 31, 32, and 33 near the branch point 34 of the branch circuit formed by connecting the transmission lines 31, 32, and 33 are reduced, and the thin line portions are formed. 35, a thin line portion 36 and a thin line portion 37 are formed. Since the line width of the transmission line in the vicinity of the branch point 34 is reduced, the area of the connection portion around the branch point 34 is reduced, and the parasitic reactance generated in the connection portion is reduced.

As described above, according to the fourth embodiment, the transmission line 31, the transmission line 32 near the branch point 34 of the branch circuit formed by connecting the transmission lines 31, 32 and 33 is connected. And the line width of the transmission line 33 is reduced to form the thin line portion 35, the thin line portion 36, and the thin line portion 37, respectively.
Since the precision of reactance adjustment in the filter unit can be improved by reducing the parasitic reactance generated in the surrounding connection portion, the performance of the high-pass filter can be improved, and the design accuracy of the high-pass filter can be improved. The effect that it can improve is produced.

The short-circuit stub 40 at the end of the filter unit according to the fourth embodiment is provided as an inductor for adjusting the reactance of the filter unit constituting the high-pass filter.
It should be noted that the function is different from that of the tip short-circuit stubs 17 and 30 provided for reducing the parasitic reactance at the connection portion as shown in the second and third embodiments. That is, it can be said that the filter unit according to the fourth embodiment is obtained by applying the branch circuit according to the first embodiment to a branch circuit configured by connecting the transmission lines 31, 32, and 33. . Further, the branch circuit according to the second or third embodiment can be applied to the branch circuit. In this case, the tip short-circuit stub 17 or the tip short-circuit stub 30 is connected to the connection part in the branch circuit. By connecting, the parasitic reactance generated at the connection portion can be reduced, and the same effect as in the case where the branch circuit according to the first embodiment is applied can be obtained.

Embodiment 5 FIG. 5 is a circuit diagram showing a configuration of a duplexer according to a fifth embodiment of the present invention. In FIG. 5, 41 is a high-pass filter, 42 is a high-pass terminal from which a signal output passed through the high-pass filter 41 is obtained,
43 is a low-pass filter, 44 is a low-pass filter 43
, A common terminal of the duplexer, 46 is a transmission line (first transmission line) connected to the high-pass filter 41, and 47 is a low-pass filter 43. A transmission line (second transmission line) to be connected; 48, a transmission line (third transmission line) to be connected to the common terminal 45;
Reference numeral 49 denotes a branch point which is regarded as a design connection center at a connection portion connecting the transmission lines 46, 47 and 48 so as to form a branch circuit, 50, 51, and 52.
Is a branch point 4 in the transmission lines 46, 47 and 48, respectively.
9, a thin line portion defined as a narrow line width portion, 5
3 is a duplexer composed of the above components.

Next, the operation will be described. Since a parasitic reactance exists at a connection around the branch point 49 to which the high-pass filter 41 and the low-pass filter 43 are connected, the pass characteristics and the reflection characteristics of the duplexer 53 are deteriorated. Therefore, the branch point 4 of the branch circuit constituted by connecting the transmission lines 46, 47 and 48 is connected.
The line widths of the transmission line 46, the transmission line 47, and the transmission line 48 in the vicinity of 9 are narrowed to form the thin line portion 50, the thin line portion 51, and the thin line portion 52, respectively. Since the line width of the transmission line near the branch point 49 is reduced, the area of the connection around the branch 49 is reduced, and the parasitic reactance generated at the connection is reduced.

As described above, according to the fifth embodiment, the transmission lines 46, 47 near the branch point 49 of the branch circuit formed by connecting the transmission lines 46, 47, and 48 are connected. Since the line width of the transmission line 48 is narrowed to form the thin line portion 50, the thin line portion 51, and the thin line portion 52, respectively,
Since the parasitic reactance generated in the surrounding connection portion can be reduced, deterioration of the pass characteristics and the reflection characteristics of the duplexer 53 can be reduced, and the design accuracy of the duplexer 53 can be improved. This has the effect.

It should be noted that the duplexer according to the fifth embodiment includes:
It can be said that the branch circuit according to the first embodiment is applied to the branch circuit formed by connecting the transmission lines 46, 47, and 48. Also, the branch circuit according to the second or third embodiment is described.
In this case, by connecting the tip short-circuit stub 17 or the short-circuit stub 30 to the connection part in the branch circuit, the parasitic reactance generated at the connection part can be reduced. The same effect as in the case where the branch circuit according to the first embodiment is applied can be obtained.

Embodiment 6 FIG. FIG. 6 is a circuit diagram showing a configuration of a duplexer according to Embodiment 6 of the present invention. 6, the same reference numerals as those in FIG. 5 denote the same or corresponding parts, and a description thereof will be omitted. 61 is a transmission line (fourth transmission line), 62 is a transmission line (fifth transmission line), 63 is a transmission line (sixth transmission line), and 64 is a transmission line 61 to form a branch circuit. A branch point 65, 6 which is regarded as a design connection center at a connection portion connecting the line 62 and the transmission line 63 (hereinafter referred to as a filter connection portion).
Reference numeral 6 denotes a thin line portion defined as a narrow line portion near the branch point 64 in each of the transmission lines 62 and 63; 67, a parallel plate capacitor (capacitor) disposed in the transmission line 62; This is a grounding element such as a via hole connected to the end opposite to the connection part. The transmission line 46 extending from the connection portion around the branch point 49 and the transmission line 61 extending from the in-filter connection portion around the branch point 64 have a configuration in which the lines are shared without providing a thin line portion. Also, the transmission line 6
2 includes a line portion 62a extending from one electrode portion of the parallel plate capacitor 67 and a line portion 62b extending from the other electrode portion of the parallel plate capacitor 67. The transmission line 63 and the grounding element 68 constitute a short-circuit stub at the tip. Further, the high-pass filter 41 is connected to the transmission line 6.
1, 62, 63, a parallel plate capacitor 67, a grounding element 68, and the like, and the filter unit shown in FIG.

Next, the operation will be described. The duplexer according to the sixth embodiment is obtained by applying the high-pass filter according to the fourth embodiment to the high-pass filter of the duplexer according to the fifth embodiment. Therefore, the operation according to the duplexer according to the sixth embodiment is obtained by adding the operation according to the high-pass filter according to the fourth embodiment to the operation according to the duplexer according to the fifth embodiment. That is, by reducing the line width of the transmission line near the junction around the junction 49 connecting the high-pass filter 41 and the low-pass filter 43, the area of the junction around the junction 49 is reduced. Therefore, the parasitic reactance generated at the connection portion is reduced. Further, in the high-pass filter 41, by reducing the line width of the transmission line near the junction in the filter around the branch point 64, the area of the junction in the filter is reduced, and the parasitic capacitance generated in the junction in the filter is reduced. The reactance is reduced, and the error of reactance adjustment related to the filter unit is reduced.

As described above, according to the sixth embodiment, the line width of the transmission line near the junction around the branch point 49 connecting the high-pass filter 41 and the low-pass filter 43 is reduced, and In the high-pass filter 41, the line width of the transmission line in the vicinity of the connection portion in the filter around the branch point 64 is configured to be narrow, so that the branch point 4
The parasitic reactance generated in the connection around the junction 9 and the connection in the filter around the branch point 64 is reduced, and the
Of the filter unit in the high-pass filter 41, and the accuracy of the reactance adjustment in the filter unit in the high-pass filter 41 can be improved. Therefore, the performance of the duplexer 53 can be improved and the design of the duplexer 53 can be improved. There is an effect that accuracy can be improved.

It should be noted that the duplexer according to the sixth embodiment includes:
The branch according to the first embodiment includes a branch circuit formed by connecting the transmission lines 46, 47 and 48, and a branch circuit formed by connecting the transmission lines 61, 62 and 63. It can be said that the circuit is applied. Further, the branch circuit according to the second or third embodiment can be applied to one or both of the branch circuits, and in this case, a connection part in the branch circuit or a connection part in a filter. By connecting the tip short-circuit stub 17 or the tip short-circuit stub 30, the parasitic reactance generated at the connection part or the connection part in the filter can be reduced, and the same effect as in the case where the branch circuit according to the first embodiment is applied. To play.

Embodiment 7 FIG. 7 is a perspective view showing a configuration of a branch circuit according to Embodiment 7 of the present invention. FIG.
In the figure, 71 is a conductor pattern provided as a branch circuit according to the first embodiment, 72 is a dielectric substrate, and 73 is a ground conductor provided on the lower surface of the dielectric substrate 72. The conductor pattern 71, the dielectric substrate 72, and the ground conductor 73 form a microstrip line.

The branch circuit according to the seventh embodiment has the same effects as the branch circuit according to the first embodiment, except that the branch circuit according to the first embodiment is configured by a microstrip line. Note that the branch circuits according to the second and third embodiments, the high-pass filter according to the fourth embodiment, and the duplexers according to the fifth and sixth embodiments can also be configured by microstrip lines. And have the same effect.

Embodiment 8 FIG. FIG. 8 is a perspective view showing a configuration of a branch circuit according to Embodiment 8 of the present invention. FIG.
In the figure, 81 is a dielectric substrate, 82 is a conductor pattern formed on the dielectric substrate 81 and provided as a branch circuit according to the first embodiment, and 83 is a predetermined distance from the dielectric substrate 81 in parallel with the dielectric substrate 81. A ground conductor 84 is spaced apart from the dielectric substrate 81 in parallel with the dielectric substrate 81.
Is a ground conductor that is disposed at a predetermined distance from the ground conductor. The conductor pattern 82, the dielectric substrate 81, and the ground conductors 83 and 84 constitute a triplate line. The structure between the ground conductor 83 and the dielectric substrate 81 and between the ground conductor 84 and the dielectric substrate 81 have a hollow structure or a structure filled with a dielectric material. The conductor pattern 82 is blocked by the ground conductor 83 and cannot be seen originally.
Are clearly shown.

The branch circuit according to the eighth embodiment is the same as the branch circuit according to the first embodiment except that the branch circuit according to the first embodiment is configured by a triplate line. Embodiment 2 and Embodiment 3
, The high-pass filter according to the fourth embodiment, and the duplexers according to the fifth and sixth embodiments can also be configured by a triplate line.
Each has the same effect.

[0046]

As described above, according to the branch circuit of the present invention, the connection section has three or more transmission lines connected to each other, and at least one of the transmission lines has at least one transmission line. The structure is configured so that the line width is narrower than the line width at the part separated from the connection part in the vicinity of the connection part, so the parasitic reactance generated at the connection part is reduced, and the transmission characteristics and reflection characteristics of the high-frequency circuit are deteriorated. Can be reduced. Further, the area of the connection portion is reduced, and the error relating to the positioning of the branch point regarded as the connection center in the design can be reduced, so that the design accuracy in the circuit design can be improved.

According to the branch circuit of the present invention, each of the transmission lines connected to each other at the connection portion is a thin line having a line width smaller than that of the transmission line having the smallest line width at a portion separated from the connection portion. Since the parts are provided in the vicinity of the connection part, the area of the connection part becomes smaller, the deterioration of the pass characteristic and the reflection characteristic of the high frequency circuit can be further reduced, and the error relating to the positioning of the branch point can be reduced. There is an effect that it is possible to reduce the size and improve the design accuracy in circuit design.

According to the branch circuit of the present invention, since three or more transmission lines connected to each other at the connection part and the stub for reactance adjustment connected to the connection part are provided, the stub for reactance adjustment is provided. Since the parasitic reactance generated at the connection portion can be reduced by setting the length appropriately according to the parasitic reactance generated at the connection portion, the effect of reducing the deterioration of the transmission characteristics and the reflection characteristics of the high-frequency circuit can be reduced. Play.

According to the branch circuit of the present invention, the connection section has three or more transmission lines connected to each other, and at least one of the transmission lines has a line width near the connection section. With a narrow line
Further, since the stub for reactance adjustment connected to the connection portion is provided, the parasitic reactance generated at the connection portion is reduced by reducing the line width near the connection portion, and the length corresponding to the reduced parasitic reactance is reduced. The addition of the reactive stub for adjusting the reactance makes it possible to further reduce the parasitic reactance generated at the connection portion, and thus has the effect of further reducing the deterioration of the transmission characteristics and reflection characteristics of the high-frequency circuit.

According to the high-pass filter of the present invention, the first transmission line, the second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, A third transmission line having one end connected to the connection between the first transmission line and the second transmission line and the other end connected to a grounding element; A filter unit including a thin line portion in which at least one of the transmission line, the second transmission line, and the third transmission line has a narrow line width near the connection portion;
Since at least one cascade-connected unit is provided, the precision of the reactance adjustment in the filter unit can be improved by reducing the parasitic reactance generated at the connection part, thereby improving the performance of the high-pass filter. And the design accuracy of the high-pass filter can be improved.

According to the high-pass filter of the present invention, the first transmission line, the second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, A third transmission line in which one end is connected to a connection between the first transmission line and the second transmission line and a grounding element is connected to the other end, and a reactance adjustment connected to the connection And at least one filter unit having a stub for connection is configured as a cascade-connected component unit, so that the precision of reactance adjustment in the filter unit can be increased by reducing the parasitic reactance generated at the connection part. In addition, the performance of the high-pass filter can be improved, and the design accuracy of the high-pass filter can be improved. .

According to the duplexer of the present invention, the first transmission line, the second transmission line, and the third transmission line connected to each other at the connection portion are opposite to the connection portion of the first transmission line. A high-pass filter connected to the end of the second transmission line; a low-pass filter connected to the end opposite to the connection of the second transmission line; and a connection opposite to the connection of the third transmission line. And at least one of the first transmission line, the second transmission line, and the third transmission line has a line width in the vicinity of the connection portion. , The parasitic reactance generated at the connection between the high-pass filter and the low-pass filter can be reduced. Can be reduced, and An effect that it is possible to improve the design accuracy.

According to the duplexer of the present invention, the first transmission line, the second transmission line, and the third transmission line connected to each other at the connection part are opposite to the connection part of the first transmission line. A high-pass filter connected to the end of the second transmission line; a low-pass filter connected to the end opposite to the connection of the second transmission line; and a connection opposite to the connection of the third transmission line. Parasitic reactance generated at the connection between the high-pass filter and the low-pass filter is reduced because the common terminal connected to the end on the side and the stub for reactance adjustment connected to the connection are provided. Therefore, it is possible to reduce the deterioration of the pass characteristics and the reflection characteristics of the duplexer and to improve the design accuracy of the duplexer.

According to the duplexer of the present invention, the fourth transmission line, the fifth transmission line including the line portion extending from one electrode portion of the capacitor and the line portion extending from the other electrode portion, A sixth transmission line, one end of which is connected to the in-filter connection part of the fourth transmission line and the fifth transmission line, and the other end of which is connected to a grounding element; At least one transmission line among the fourth transmission line, the fifth transmission line, and the sixth transmission line is provided with a filter unit having a thin line portion whose line width becomes narrow in the vicinity of a connection portion in the filter. Since it is configured to have at least one as a structural unit related to the connection structure,
The parasitic reactance generated at the connection between the high-pass filter and the low-pass filter and the connection inside the filter of the high-pass filter is reduced, so that the deterioration of the pass and reflection characteristics of the duplexer can be reduced, and the high-pass filter Since the precision of the reactance adjustment in the filter unit in the inside can be improved, there is an effect that the performance of the duplexer can be improved and the design accuracy of the duplexer can be improved.

According to the duplexer of the present invention, the fourth transmission line, the fifth transmission line including the line portion extending from one electrode portion of the capacitor and the line portion extending from the other electrode portion, A sixth transmission line having one end connected to the in-filter connection between the fourth transmission line and the fifth transmission line, and a grounding element connected to the other end, and a sixth connection connected to the in-filter connection. And at least one filter unit having a reactance adjusting stub as a constituent unit related to the cascade connection structure of the high-pass filter, so that the connection unit between the high-pass filter and the low-pass filter and the The parasitic reactance generated in the connection portion of the high-pass filter is reduced, so that the deterioration of the pass characteristics and the reflection characteristics of the duplexer can be reduced and the filter unit in the high-pass filter is reduced. Since it is possible to improve the accuracy of reactance adjustment in an effect that improves the performance of the duplexer can be improved design accuracy of the duplexer.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a branch circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a branch circuit according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a branch circuit according to a third embodiment of the present invention.

FIG. 4 is a circuit diagram illustrating a configuration of a filter unit of a high-pass filter according to Embodiment 4 of the present invention, and a cross-sectional view illustrating a partial circuit portion of the filter unit.

FIG. 5 is a circuit diagram showing a configuration of a duplexer according to a fifth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a configuration of a duplexer according to a sixth embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration of a branch circuit according to a seventh embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of a branch circuit according to an eighth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a conventional band-pass filter.

[Explanation of symbols]

1,2,3,11,12,13,15,21,22,2
3,28 transmission line, 4,14,24,34,49,6
4 branch points, 5, 6, 7, 25, 26, 27, 35, 3
6, 37, 50, 51, 52, 65, 66 Thin line portion, 1
6, 29, 39, 68 Grounding element, 17, 30 Tip short-circuit stub (reactance adjustment stub), 31, 46
Transmission line (first transmission line), 32, 47 Transmission line (second transmission line), 32a, 32b, 62a, 62b
Line parts, 33, 48 transmission line (third transmission line), 38, 67 parallel plate capacitor (capacitor), 40 tip short-circuit stub, 41 high-pass filter,
42 high-pass terminal, 43 low-pass filter, 44
Low-pass terminal, 45 common terminal, 53 duplexer, 61
Transmission line (fourth transmission line), 62 transmission line (fifth transmission line), 63 transmission line (sixth transmission line), 7
1,82 conductor pattern, 72,81 dielectric substrate, 7
3,83,84 Ground conductor.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiyuki Chatani 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. 2-3-2, Mitsui Electric Co., Ltd. (72) Inventor Manabu Kurihara, 25, Yamazaki, Kamakura-shi, Kanagawa F-term (reference) 5J006 HB01 HB03 HB04 HB13 HB17 HB22 JA04 JA06 JA31 KA03 KA13 KA23 LA07 LA13 NA04 NA08 NB10 NC03

Claims (10)

[Claims] 1. A transmission system comprising: three or more transmission lines connected to each other at a connection part, wherein at least one of the transmission lines has a line width at a part near the connection part and separated from the connection part. A branch circuit comprising a thin line portion whose line width is narrower than that of the branch circuit. 2. A transmission line connected to each other at a connection portion, a thin line portion having a line width smaller than the line width of the transmission line having the smallest line width at a portion separated from the connection portion, respectively, in the vicinity of the connection portion. The branch circuit according to claim 1, further comprising: 3. A branch circuit comprising: three or more transmission lines connected to each other at a connection part; and a stub for reactance adjustment connected to the connection part. 4. The branch circuit according to claim 1, further comprising a reactance adjusting stub connected to the connection portion. 5. A first transmission line, a second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, the first transmission line and the second transmission line. A third transmission line, one end of which is connected to the connection with the second transmission line, and the other end of which is connected to a grounding element. Wherein at least one of the second transmission line and the third transmission line has at least one filter unit having a thin line portion whose line width decreases in the vicinity of the connection portion as a cascade-connected structural unit. A high-pass filter. 6. A first transmission line, a second transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, the first transmission line and the second transmission line. A filter comprising: a third transmission line having one end connected to the connection with the second transmission line and the grounding element connected to the other end; and a reactance adjusting stub connected to the connection. A high-pass filter comprising at least one unit as a cascade-connected component unit. 7. A first transmission line, a second transmission line, and a third transmission line connected to each other at a connection portion, and connected to an end of the first transmission line on a side opposite to the connection portion. A high-pass filter, a low-pass filter connected to the end of the second transmission line opposite to the connection portion, and a low-pass filter connected to an end of the third transmission line opposite to the connection portion. And a common terminal connected to an end portion, wherein at least one of the first transmission line, the second transmission line, and the third transmission line is provided near the connection portion. A duplexer comprising a thin line portion having a narrow line width. 8. A first transmission line, a second transmission line, and a third transmission line connected to each other at a connection portion, and connected to an end of the first transmission line on a side opposite to the connection portion. A high-pass filter, a low-pass filter connected to the end of the second transmission line opposite to the connection portion, and a low-pass filter connected to an end of the third transmission line opposite to the connection portion. A duplexer comprising: a common terminal connected to an end portion; and a reactance adjusting stub connected to the connection portion. 9. A fourth transmission line, a fifth transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion, and the fourth transmission line and the fifth transmission line. A sixth transmission line, one end of which is connected to the connection part in the filter with the transmission line of No. 5 and the other end of which is connected to the grounding element; At least one of the fifth transmission line and the sixth transmission line is provided with a filter unit having a thin line portion whose line width is reduced in the vicinity of a connection portion in the filter, in a cascade connection structure of a high-pass filter. The duplexer according to claim 7, wherein the duplexer includes at least one of the constituent units. 10. A fourth transmission line comprising: a fourth transmission line; a fifth transmission line including a line portion extending from one electrode portion of the capacitor and a line portion extending from the other electrode portion; A sixth transmission line having one end connected to the connection in the filter with the transmission line of No. 5, and a grounding element connected to the other end; and a stub for reactance adjustment connected to the connection in the filter. 9. The duplexer according to claim 7, wherein the duplexer includes at least one filter unit including: a filter unit having a cascade connection structure of a high-pass filter.