JP2008294797A - Laminated band-pass filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, in a lumped constant type, it becomes difficult to form transformer structure with two coils accompanying miniaturization and also a sufficient mutual inductance generated by magnetic coupling can not be obtained. <P>SOLUTION: A band-pass filter is formed, in which a first coil and a second coil are connected between input/output terminals, a first capacitor is connected in parallel with a serial circuit between the first coil and the second coil, a second capacitor is connected between the input terminal side and earth of the first coil, a third coil is connected between a connection point of the first coil and the second coil and earth and a third capacitor is connected between the output terminal side and earth of the second coil. In the first coil and the second coil, one end of a conductor pattern for the first coil and one end of a conductor pattern for the second coil are connected to each other, a linear conductor pattern is formed between a middle point of the conductor pattern for coils constituting the first coil and the second coil and an earth terminal and the third coil is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminated band-pass filter in which an insulator layer and a conductor pattern are laminated and a band-pass filter is formed in the laminated body.

As shown in FIG. 8, a capacitor C4 is connected between the input terminal 81 and the output terminal 82, and a parallel circuit of a coil L4 and a capacitor C5 is connected between the input terminal 81 and the ground, as shown in FIG. In some cases, a parallel circuit of a coil L5 and a capacitor C6 is connected between 82 and ground, and the coils of the two parallel circuits are magnetically coupled. Such a band-pass filter is configured, for example, by laminating an insulator layer and a conductor pattern, and forming a circuit with the conductor pattern in the laminate (see, for example, Patent Document 1).
Further, as shown in FIG. 9, capacitors C7, C8, C9 are connected between the input terminal 91 and the output terminal 92 in another conventional bandpass filter, and λ is connected between the connection point of the capacitor C7 and the capacitor C8 and the ground. A strip line 93 constituting a / 4 resonator is connected, a strip line 94 constituting a λ / 4 resonator is connected between the connection point of the capacitor C8 and the capacitor C9 and the ground, and the strip line 93 and the strip line 94 are combined. Some are line-coupled. C10 is a capacitance component generated in the strip line 93, and C11 is a capacitance component generated in the strip line 94.

Japanese Patent Laid-Open No. 11-261362

In recent years, mobile communication devices such as mobile phones have been reduced in size and height, and this type of bandpass filter used in mobile communication devices is also desired to be downsized. However, in the lumped constant type band-pass filter as shown in FIG. 8, it is difficult to form a transformer structure by the coil L4 and the coil L5 as the size is reduced, and the mutual inductance generated by the magnetic coupling is also sufficient. I can't get anything.
In addition, since the distributed constant type bandpass filter as shown in FIG. 9 forms a λ / 4 resonator and is comb-line coupled, although there is a slight difference in the dielectric constant of the dielectric, The length of the strip line is almost determined by the wavelength, and the shape of the bandpass filter cannot be sufficiently reduced.

  An object of the present invention is to provide a multilayer bandpass filter that can be reduced in size without degrading characteristics.

  In the multilayer bandpass filter of the present invention, an insulator layer and a conductor pattern are laminated and a first coil and a second coil are connected between input / output terminals in the laminate, and the first coil and the second coil are connected. A first capacitor is connected in parallel with the series circuit of the coil, a second capacitor is connected between the input terminal side of the first coil and the ground, and a connection point between the first coil and the second coil and the ground A band-pass filter is formed in which a third capacitor is connected between the output terminal side of the second coil and the ground, and the first coil and the second coil are connected to the first coil. A coil conductor constituting the first coil and the second coil is connected in series by connecting one end of the coil conductor pattern constituting the coil and one end of the coil conductor pattern constituting the second coil to each other. The midpoint of the pattern Third coil is formed line-shaped conductor pattern between the ground terminals are formed. The first coil and the second coil are each formed by connecting coil conductor patterns between insulator layers in a spiral manner, and arranged side by side in a stacked state so that their winding axes do not overlap each other. Are connected in series by connecting the coil conductor pattern constituting one end of the first coil and the coil conductor pattern constituting one end of the second coil to each other, and connecting the one end of the first coil and the second coil A linear conductor pattern is formed between the midpoint of the coil conductor pattern constituting one end of the coil and the ground terminal, thereby forming a third coil.

In the multilayer bandpass filter of the present invention, an insulator layer and a conductor pattern are laminated and a first coil and a second coil are connected between input / output terminals in the laminate, and the first coil and the second coil are connected. A first capacitor is connected in parallel with the series circuit of the coil, a second capacitor is connected between the input terminal side of the first coil and the ground, and a connection point between the first coil and the second coil and the ground A band-pass filter is formed in which a third capacitor is connected between the output terminal side of the second coil and the ground, and the first coil and the second coil are connected to the first coil. A coil conductor constituting the first coil and the second coil is connected in series by connecting one end of the coil conductor pattern constituting the coil and one end of the coil conductor pattern constituting the second coil to each other. The midpoint of the pattern Since a linear conductor pattern is formed between the ground terminals to form the third coil, a bandpass filter can be formed without using the magnetic coupling between the first coil and the second coil. A sufficient inductance value can be obtained by the linear conductor pattern connected between the midpoint of the coil conductor pattern constituting the first coil and the second coil and the ground terminal.
In the multilayer bandpass filter according to the present invention, the first coil and the second coil are connected between the input / output terminals in the multilayer body by laminating the insulator layer and the conductor pattern. A first capacitor is connected in parallel with the series circuit of the two coils, a second capacitor is connected between the input terminal side of the first coil and the ground, and a connection point between the first coil and the second coil; A band-pass filter is formed in which a third coil is connected between the ground and a third capacitor is connected between the output terminal side of the second coil and the ground. The first coil and the second coil are respectively A coil conductor formed by connecting coil conductor patterns between insulating layers in a spiral manner and arranged side by side in a separated state in the laminate so that the winding axes do not overlap each other, and constitutes one end of the first coil Pattern and second co The coil conductor patterns constituting one end of the coil are connected in series, and a wire is connected between the middle point of the coil conductor pattern constituting one end of the first coil and one end of the second coil and the ground terminal. Since the third coil is formed by forming the conductor pattern, the band-pass filter can be formed without using the magnetic coupling between the first coil and the second coil. A sufficient inductance value can be obtained by a linear conductor pattern connected between the middle point of the coil conductor pattern constituting one end of the second coil and one end of the second coil and the ground terminal.
Therefore, the multilayer bandpass filter of the present invention can be reduced in size without deteriorating the characteristics.

  In the multilayer bandpass filter of the present invention, an insulator layer and a conductor pattern are laminated and a first coil and a second coil are connected between input / output terminals in the laminate, and the first coil and the second coil are connected. A first capacitor is connected in parallel with the series circuit of the coil, a second capacitor is connected between the input terminal side of the first coil and the ground, and a connection point between the first coil and the second coil and the ground A band-pass filter is formed in which a third coil is connected to the third coil and a third capacitor is connected between the output terminal side of the second coil and the ground. In the first coil and the second coil, a coil conductor pattern constituting the first coil and a coil conductor pattern constituting the second coil are formed on the insulator layer, and the first coil conductor pattern Either one end and one end of the second coil conductor pattern are connected in series, or the coil conductor patterns between the insulator layers are connected in a spiral manner so that the winding axes do not overlap each other. The coil conductor pattern that constitutes one end of the first coil and the coil conductor pattern that constitutes one end of the second coil are connected in series by being arranged side by side in a separated state in the laminated body. The Between the intermediate point of the coil conductor pattern that constitutes both the first coil and the second coil and the ground terminal, or of the coil conductor pattern that constitutes both one end of the first coil and one end of the second coil A linear conductor pattern is formed between the intermediate point and the ground terminal to form a third coil. Therefore, the multilayer bandpass filter according to the present invention includes a first coil and a second coil, or an intermediate point of a coil conductor pattern constituting one end of the first coil and one end of the second coil, and a ground terminal. Since the linear conductor pattern is formed on the first and second coils, it is possible to prevent the first coil and the second coil from being magnetically coupled and to connect the first coil and the second coil by the linear conductor pattern. A third coil having a sufficient inductance value between the point and the ground can be formed.

Hereinafter, the laminated band-pass filter of the present invention will be described with reference to FIGS.
1 is a circuit diagram of an embodiment of a multilayer bandpass filter according to the present invention, FIG. 2 is an exploded perspective view illustrating a first embodiment of the multilayer bandpass filter according to the present invention, and FIG. 3 is a multilayer band according to the present invention. It is a perspective view which shows the Example of a pass filter.
In FIG. 1, 11 is an input terminal and 12 is an output terminal.
Between the input terminal 11 and the output terminal 12, a coil L1 and a coil L2 are connected in series. A capacitor C1 is connected in parallel with the series circuit of the coil L1 and the coil L2.
A capacitor C2 is connected between the input terminal 11 and the ground. A capacitor C3 is connected between the output terminal 12 and the ground. Further, the coil L3 is connected between the connection point between the coil L1 and the coil L2 and the ground.

Such a band pass filter is formed in a laminated body by laminating an insulator layer and a conductor pattern as shown in FIG.
The insulator layers 21A to 21I are formed using an insulating material such as a magnetic material, a non-magnetic material, or a dielectric material.
A coil conductor pattern 22A, a coil conductor pattern 23A, and a linear conductor pattern 24 are formed on the surface of the insulator layer 21A. The coil conductor pattern 22A and the coil conductor pattern 23A are each formed with less than one turn, and one end of the coil conductor pattern 22A and one end of the coil conductor pattern 23A are connected to each other. One end of the linear conductor pattern 24 is connected to an intermediate point of the coil conductor pattern formed by connecting the two coil conductor patterns. The linear conductor pattern 24 is linearly formed from the middle point of the coil conductor pattern formed by connecting the two coil conductor patterns to the side surface of the insulator layer 21A, and the other end of the insulator layer 21A. Pulled out to the side.
A coil conductor pattern 22B and a coil conductor pattern 23B are formed on the surface of the insulator layer 21B. The coil conductor pattern 22B and the coil conductor pattern 23B are each formed with less than one turn, and one end of the coil conductor pattern 22B is connected to the other end of the coil conductor pattern 22A via a conductor in the through hole. One end of the coil conductor pattern 23B is connected to the other end of the coil conductor pattern 23A via a conductor in the through hole. The other end of the coil conductor pattern 22B and the other end of the coil conductor pattern 23B are each drawn to the end face of the insulator layer 21B. In this way, the coil conductor pattern 22A and the coil conductor pattern 22B are spirally connected to form the coil L1, and the coil conductor pattern 23A and the coil conductor pattern 23B are spirally connected to form the coil L2. It is formed.
A grounding conductor pattern G1 is formed on the surface of the insulating layer 21C. The grounding conductor pattern G1 is led out to the side surface of the insulating layer 21C facing the lead end.
The capacitor conductor pattern 25A and the capacitor conductor pattern 26A are formed on the surface of the insulator layer 21D so as not to contact each other. The capacitor conductor pattern 25A and the capacitor conductor pattern 26A are respectively formed at positions facing the ground conductor pattern G1, and the respective leading ends are led out to the end surface of the insulating layer 21D.
A grounding conductor pattern G2 is formed on the surface of the insulating layer 21E. The grounding conductor pattern G2 is formed at a position facing the capacitor conductor pattern 25A and the capacitor conductor pattern 26A, and the lead-out end is drawn out to the side surface facing the insulator layer 21E.
The capacitor conductor pattern 25B and the capacitor conductor pattern 26B are formed on the surface of the insulating layer 21F so as not to contact each other. The conductor pattern for capacitor 25B and the conductor pattern for capacitor 26B are formed at positions facing the ground conductor pattern G2, respectively, and each lead-out end is drawn to the end face of the insulator layer 21F. On the surface of the insulator layer 21G, The capacitor conductor pattern 27A and the capacitor conductor pattern 27B are formed so as not to contact each other. The capacitor conductor pattern 27A is formed to extend in the length direction of the insulating layer 21G so as to face the capacitor conductor pattern 25B and the capacitor conductor pattern 26B, and the capacitor conductor via the conductor in the through hole. Connected to pattern 25B. The capacitor conductor pattern 27B is formed to extend in the length direction of the insulating layer 21G so as to face the capacitor conductor pattern 25B and the capacitor conductor pattern 26B, and is connected to the capacitor via the conductor in the through hole. The conductor pattern 26B is connected.
The capacitor conductor pattern 25C and the capacitor conductor pattern 26C are formed on the surface of the insulating layer 21H so as not to contact each other. The capacitor conductor pattern 25C is formed so as to face the capacitor conductor pattern 27A and the capacitor conductor pattern 27B, and is connected to the capacitor conductor pattern 27A via the conductor in the through hole. The capacitor conductor pattern 26C is formed so as to face the capacitor conductor pattern 27A and the capacitor conductor pattern 27B, and is connected to the capacitor conductor pattern 27B through the conductor in the through hole. The lead-out end of the capacitor conductor pattern 25C and the lead-out end of the capacitor conductor pattern 26C are led out to the end face of the insulator layer 21H.
An insulator layer 21I is stacked on the insulator layer 21H.
As shown in FIG. 3, in the laminated body thus laminated, the input terminal 31 and the output terminal 32 are formed on the end face of the laminated body, and the ground terminal G is formed on the side surface. The coil conductor pattern 22B and the capacitor conductor patterns 25A, 25B, and 25C are the input terminal 31, the coil conductor pattern 23B and the capacitor conductor patterns 26A, 26B, and 26C are the output terminal 32, and the linear conductor pattern 24. And the ground conductor patterns G1 and G2 are connected to the ground terminal 33, and the ground conductor patterns G1 and G2 are connected to the ground terminal 34.

  In the multilayer bandpass filter formed in this way, the coil L1 is formed by the coil conductor pattern 22A and the coil conductor pattern 22B, and the coil L2 is formed by the coil conductor pattern 23A and the coil conductor pattern 23B. 24 forms a coil L3. Further, the capacitance between the capacitor conductor pattern 27A and the capacitor conductor patterns 25B, 25C, 26B, 26C located on both sides thereof, the capacitor conductor pattern 27B, and the capacitor conductor patterns 25B, 25C, 26B located on both sides thereof, The capacitor C1 is formed by the capacitance between 26C. Further, the capacitor C2 is formed by the capacitance between the capacitor conductor pattern 25A and the ground conductor patterns G1 and G2 located on both sides thereof, and the capacitance between the ground conductor pattern G2 and the capacitor conductor pattern 25B. Furthermore, a capacitor C3 is formed by the capacitance between the capacitor conductor pattern 26A and the ground conductor patterns G1 and G2 located on both sides thereof, and the capacitance between the ground conductor pattern G2 and the capacitor conductor pattern 26B.

  Such a multilayer bandpass filter has a dielectric constant of 21 for the insulator layer, a line width of the coil conductor pattern and the linear conductor pattern of 70 μm, and a total element shape of 1 mm × 0.5 mm × 0.3 mm. As a result, the input / output impedance is 50Ω, and as shown in FIG. 4, the passband is 2.4 to 2.5 GHz, the insertion loss in the passband is 2.3 dB, the reflection loss in the passband is 17.6 dB, 500 to The attenuation at 1900 MHz was 24.4 dB. In FIG. 4, the horizontal axis represents frequency, the vertical axis represents attenuation, 41 represents transmission characteristics, and 42 represents reflection characteristics.

FIG. 5 shows a second embodiment of the multilayer bandpass filter of the present invention, and is a perspective view showing only the insulator layer 21A.
Similarly to the first embodiment, the coil conductor pattern 52A and the coil conductor pattern 53A are each formed with less than one turn on the surface of the insulating layer 21A, and one end of the coil conductor pattern 52A and the coil conductor pattern are formed. One ends of 53A are connected to each other. One end of a linear conductor pattern 54 is connected to an intermediate point of the coil conductor pattern formed by connecting the two coil conductor patterns. In the present embodiment, the meandering so that the linear conductor pattern 54 extends while meandering from the middle point of the coil conductor pattern formed by connecting the two coil conductor patterns to the side surface of the insulator layer 21A. The other end is drawn out to the side surface of the insulator layer 21A.

FIG. 6 is an exploded perspective view showing a third embodiment of the multilayer bandpass filter of the present invention.
A coil conductor pattern 62 and a coil conductor pattern 63 are formed on the surface of the insulating layer 61A. The coil conductor pattern 62 and the coil conductor pattern 63 are each formed in a meander shape, and one end of the coil conductor pattern 62 and one end of the coil conductor pattern 63 are connected to each other. One end of a linear conductor pattern 64 is connected to an intermediate point of the coil conductor pattern formed by connecting the two coil conductor patterns. The linear conductor pattern 64 is linearly formed from the midpoint of the coil conductor pattern formed by connecting the two coil conductor patterns to the side surface of the insulator layer 61A, and the other end of the insulator layer 61A. Pulled out to the side.
A grounding conductor pattern G1 is formed on the surface of the insulating layer 61B. The grounding conductor pattern G1 is led out to the side surface of the insulating layer 61B facing the lead end.
A capacitor conductor pattern 65A and a capacitor conductor pattern 66A are formed on the surface of the insulating layer 61C. The capacitor conductor pattern 65A and the capacitor conductor pattern 66A are formed at positions facing the ground conductor pattern G1, and the respective leading ends are led out to the end surface of the insulating layer 61C.
A grounding conductor pattern G2 is formed on the surface of the insulating layer 61D. The grounding conductor pattern G2 is formed at a position facing the capacitor conductor pattern 65A and the capacitor conductor pattern 66A, and the lead-out end is drawn out to the side surface facing the insulator layer 61D.
A capacitor conductor pattern 65B and a capacitor conductor pattern 66B are formed on the surface of the insulating layer 61E. The capacitor conductor pattern 65B and the capacitor conductor pattern 66B are formed at positions facing the ground conductor pattern G2, and the respective leading ends are led out to the end surface of the insulating layer 61E.
A capacitor conductor pattern 67A and a capacitor conductor pattern 67B are formed on the surface of the insulating layer 61F. Each of the capacitor conductor pattern 67A and the capacitor conductor pattern 67B is formed so as to face the capacitor conductor pattern 65B and the capacitor conductor pattern 66B, and the capacitor conductor pattern 67A and the capacitor conductor pattern 65B are in the through hole. The capacitor conductor pattern 67B and the capacitor conductor pattern 66B are connected via the conductor in the through hole.
A capacitor conductor pattern 65C and a capacitor conductor pattern 66C are formed on the surface of the insulating layer 61G. The capacitor conductor pattern 65C and the capacitor conductor pattern 66C are both formed so as to face the capacitor conductor pattern 67A and the capacitor conductor pattern 67B, and the capacitor conductor pattern 65C and the capacitor conductor pattern 67A are in the through-hole. The conductor pattern for capacitor 66C and the conductor pattern for capacitor 67B are connected via the conductor in the through hole. The lead-out end of the capacitor conductor pattern 65C and the lead-out end of the capacitor conductor pattern 66C are led out to the end face of the insulator layer 61G.
An insulating layer 61H is laminated on the insulating layer 61G.
In the laminated body thus laminated, an input terminal and an output terminal are formed on the end face, and a ground terminal is formed on the side face. The coil conductor pattern 62 and the capacitor conductor patterns 65A, 65B, and 65C are input terminals, the coil conductor pattern 63 and the capacitor conductor patterns 66A, 66B, and 66C are output terminals, and the linear conductor pattern 64 and the like. The ends and the ground conductor patterns G1 and G2 are connected to the ground terminal.
In the multilayer bandpass filter formed in this way, the coil L1 is formed by the coil conductor pattern 62, the coil L2 is formed by the coil conductor pattern 63, and the coil L3 is formed by the linear conductor pattern 64. The capacitor C1 is formed by the capacitance between the capacitor conductor pattern 67A and the capacitor conductor patterns 25B, 25C, 26B, and 26C and the capacitance between the capacitor conductor pattern 27B and the capacitor conductor patterns 25B, 25C, 26B, and 26C. The Further, the capacitor C2 is formed by the capacitance between the capacitor conductor pattern 25A and the ground conductor patterns G1 and G2 and the capacitance between the ground conductor pattern G2 and the capacitor conductor pattern 25B. Furthermore, a capacitor C3 is formed by the capacitance between the capacitor conductor pattern 26A and the ground conductor patterns G1 and G2 and the capacitance between the ground conductor pattern G2 and the capacitor conductor pattern 26B.

FIG. 7 shows a fourth embodiment of the multilayer bandpass filter of the present invention, and is a perspective view showing only the insulator layer 61A.
Similarly to the third embodiment, the coil conductor pattern 72 and the coil conductor pattern 73 are respectively formed in a meander shape on the surface of the insulating layer 61A, and one end of the coil conductor pattern 72 and the coil conductor pattern 73 are formed. Are connected to each other. One end of a linear conductor pattern 64 is connected to an intermediate point of the coil conductor pattern formed by connecting the two coil conductor patterns. The linear conductor pattern 64 is formed in a meander shape, and the other end is drawn out to the side surface of the insulator layer 61A.

  The embodiment of the multilayer bandpass filter of the present invention has been described above, but the present invention is not limited to this embodiment. For example, in the second embodiment, the linear conductor pattern may be formed in a spiral shape. In the third and fourth embodiments, the coil conductor patterns 62 and 72 and the coil conductor patterns 63 and 73 may be linearly formed from the connection point to the end face of the insulator layer. . Further, in the third and fourth embodiments, the coil conductor pattern and the linear conductor pattern may be formed in a spiral shape.

It is a circuit diagram of the Example of the multilayer bandpass filter of this invention. 1 is an exploded perspective view showing a first embodiment of a multilayer bandpass filter according to the present invention. It is a perspective view which shows the Example of the laminated type band pass filter of this invention. It is a characteristic view of the multilayer bandpass filter of the present invention. It is a perspective view which shows the 2nd Example of the multilayer type band pass filter of this invention. It is a disassembled perspective view which shows the 3rd Example of the multilayer type band pass filter of this invention. It is a perspective view which shows the 4th Example of the laminated type band pass filter of this invention. It is a circuit diagram of the conventional band pass filter. It is a circuit diagram of another conventional bandpass filter.

Explanation of symbols

L1, L2, L3 Coils C1, C2, C3 Capacitors

Claims (3)

A first coil and a second coil are connected between the input and output terminals in the laminated body by laminating an insulator layer and a conductor pattern, and a first circuit in parallel with a series circuit of the first coil and the second coil. 1 capacitor is connected, a second capacitor is connected between the input terminal side of the first coil and the ground, and a third coil is connected between the connection point of the first coil and the second coil and the ground. A band pass filter is formed in which a third capacitor is connected between the output terminal side of the second coil and the ground,
The first coil and the second coil are connected in series by connecting one end of the coil conductor pattern constituting the first coil and one end of the coil conductor pattern constituting the second coil to each other. And a third coil is formed by forming a linear conductor pattern between a ground point and an intermediate point between the first coil and the coil conductor pattern constituting the second coil. Type bandpass filter. A first coil and a second coil are connected between the input and output terminals in the laminated body by laminating an insulator layer and a conductor pattern, and a first circuit in parallel with a series circuit of the first coil and the second coil. 1 capacitor is connected, a second capacitor is connected between the input terminal side of the first coil and the ground, and a third coil is connected between the connection point of the first coil and the second coil and the ground. A band pass filter is formed in which a third capacitor is connected between the output terminal side of the second coil and the ground,
The first coil and the second coil are each formed by spirally connecting coil conductor patterns between insulator layers, and arranged side by side in a stacked state so that their winding axes do not overlap each other. The coil conductor pattern constituting one end of the first coil and the coil conductor pattern constituting one end of the second coil are connected in series, and the one end of the first coil and the second conductor pattern are connected in series. A multilayer bandpass filter, wherein a third coil is formed by forming a linear conductor pattern between an intermediate point of a coil conductor pattern constituting one end of the coil and a ground terminal.   The linear conductor pattern connected between the middle point of the coil conductor pattern constituting one end of the first coil and one end of the second coil and the ground terminal is formed in a meander shape. The multilayer bandpass filter described.

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