JP2001185972A - Laminated filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated filter which can effectively suppress fluctuation of filter characteristics such as a degree of coupling even if a positional shift is caused. SOLUTION: On a laminate substrate formed by laminating dielectric layers, a 1st resonance pattern composed of a capacitive part 5 and an inductive part 3 constituting a 1st resonance circuit and a 2nd resonance pattern composed of a capacitive part 6 and an inductive part 4 constituting a 2nd resonance circuit are arranged; and capacitive coupling is obtained by making the capacitive parts 5 and 6 of both the resonance patterns correspond to each other along the thickness across the dielectric layers and inductive coupling is obtained by arranging parts of the inductive parts 33 and 43 of the resonance patterns 3 and 4 closely to each other, thus obtaining a laminated filter. The inductive coupling part Y of both the resonance patterns is formed on the inductive parts 3 and 4 extending in the same direction as the direction of variation of the capacitive coupling by the capacitive parts 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band-pass type laminated filter in which two resonance patterns are arranged on a laminated substrate formed by laminating dielectric layers.

[0002]

2. Description of the Related Art Conventionally, a band-pass filter has been used for RF.
It is used for circuit boards for modules, used for high-frequency radio units such as mobile communication phones, and used for duplexers and the like.

Such a band-pass filter passes only a signal in a desired frequency band, and has a structure shown in FIG. 7A in an equivalent circuit.

That is, the equivalent inductance component L1
For example, two resonance circuits R11 and R12 in which 1, L12 and capacitance components C11 and C12 are connected in parallel are arranged, and both are coupled. This bond is simply referred to as M.

As shown in FIG. 7B, a specific coupling structure is such that two resonance circuits R11 and R12 are connected to a capacitance component C3.
As shown in FIG. 7 (c),
An inductive coupling type in which two resonance circuits R11 and R12 are coupled by an inductance component L31 such as a coil is known.

In recent years, with the miniaturization of electronic components, a resonator forming a band-pass filter has been constituted by a strip line (resonance pattern) embedded in a laminate formed by laminating a plurality of dielectric layers. I was Under the current situation where the cutoff frequency is increased (a filter that forms an attenuation pole below 1 GHz), an equivalent circuit as shown in FIG. 8 has been known.

[0007] These strip lines have a capacitance component and an inductance component in a distributed constant manner.
Thereby, the LC resonance circuits R21 and R22 are equivalently configured. Then, the two strip lines are capacitively or inductively coupled to form a filter. The capacitance component of the capacitive coupling is denoted by C32, and the inductance component of the inductive coupling is denoted by L32.

[0008]

However, when a strip line as an internal resonance pattern is formed in the above-mentioned laminated substrate, a via hole conductor and a green sheet of a dielectric layer serving as the laminated substrate are provided. Then, a conductive paste is filled in the through hole, and a predetermined conductive pattern is formed on the dielectric green sheet by printing the conductive paste. At the same time, a conductor pattern which becomes the ground potential is formed.

The dielectric green sheets on which such conductor patterns are formed are laminated and integrated in consideration of the lamination order of the laminated substrates. After that, the dielectric green sheet, the conductor pattern disposed on each dielectric layer, and the ground potential pattern are integrally sintered.

[0010] In such a forming step, printing misregistration of the conductor pattern, lamination displacement of the dielectric green sheet, and the like occur. Actually, a position shift occurs in a range of about 50 μm.

[0011] When such a displacement occurs, the degree of coupling between the two resonance circuits fluctuates.

For example, in a capacitively-coupled band-pass filter having a pass band of 1 to several GHz shown in FIG.
When the coupling capacitance component C31 is 1 to several pF and the thickness of one dielectric layer is 50 μm, the facing area of the strip line that achieves the capacitive coupling C31 is 500 μm.
m square (one side is 500 μm), and -50 in a plane
Due to the displacement of about 50 μm, the coupling capacitance component C31 increases or decreases by about 40%.

Due to the change of the coupling capacitance C31, the matching of the pass band is deteriorated, the pass band is changed, and the like, and the characteristics of the band pass filter are deteriorated.

In the case of the inductive coupling type shown in FIG.
When a position shift of about −50 to +50 μm occurs in the plane, the length of the strip line formed between the dielectric layers changes by −200 to 200 μm.

When the relative dielectric constant is 10, the distance between the ground potential and the strip line is 400 μm, the inductance component changes from 0.5 to 1.0 nH, and when the inductive coupling inductance component is 2.0 nH. , 30
変 動 50% variation. As a result, similar to the case of the capacitive coupling, the characteristics of the band-pass filter such as the deterioration of the matching of the pass band and the change of the pass band deteriorate.

In order to prevent such instability of the characteristics, for example, a coupling structure of two equivalent resonance circuits as shown in FIG. 8 is connected in parallel with a coupling capacitance component C32 and an inductive coupling inductance component L32. It is possible. Then, capacitive coupling is performed at a part of the strip line in the laminate substrate, and at the same time, inductive coupling is achieved.

In such a structure, the inductance component L32 of the inductive coupling becomes small. In order to avoid this, it is necessary to enlarge the site for inductive binding.
As a result, the length of the strip line had to be increased.

As a result, there is a problem that the shape of the laminated substrate becomes large.

FIG. 3 shows the equivalent circuit shown in FIG. 7 converted by Y-Δ conversion. In this case, two resonance circuits R
1 and R2 are mainly capacitive coupling C, and a common inductance component L between the inductance components L1 and L2 of the two resonance circuits R1 and R2 and the ground potential.
Need to be formed.

However, even with the multilayer filter shown in the equivalent circuit of FIG. 3, the change in the coupling degree due to the displacement described in FIGS. 7B and 7C was not eliminated.

The present invention has been devised in view of the above-described problems. The coupling between two equivalent resonance circuits is capacitively coupled and inductively coupled, and even when a positional shift occurs, the degree of coupling is reduced. It is an object of the present invention to provide a multilayer filter capable of effectively suppressing the fluctuation of the filter characteristic which can effectively suppress the fluctuation of the filter characteristic.

It is another object of the present invention to provide a multilayer filter which can minimize the length of a resonance pattern which is a strip line and can reduce the size.

[0023]

According to a first aspect of the present invention, a first resonance circuit comprising a capacitor portion and an inductor portion constituting a first resonance circuit is provided on a laminated substrate formed by laminating a plurality of dielectric layers. A pattern and a second resonance pattern composed of a capacitance part and an inductor part constituting a second resonance circuit are arranged, and the capacitance parts of both resonance patterns are opposed to each other in the thickness direction via a dielectric layer. Coupling, in a multilayer filter that achieves inductive coupling by arranging a part of the inductor portion of both resonance patterns close to each other, the degree of coupling of the inductive coupling portion of both resonance patterns, that is, the inductance component of the inductive coupling portion is: This is a multilayer filter that varies in inverse proportion to the degree of coupling of the capacitive coupling between the two resonance patterns, that is, the capacitance component of the capacitive coupling section. That is, the inductively coupled portions of the two resonance patterns are present on the inductor portion extending in the same direction as the direction in which the capacitive coupling of the capacitance portions of the two resonance patterns fluctuates.

According to a second aspect of the present invention, the tip portions of the inductance portions of the two resonance patterns are connected to each other and connected to a ground potential by connection means comprising a via-hole conductor penetrating the dielectric layer. This is a laminated filter.

[0025]

In the multilayer filter of the present invention, the resonance pattern is
It is composed of a capacitance section and an inductor section (strip line), and is arranged between different dielectric layers.

A capacitance portion is disposed at a part of the resonance pattern, for example, at one end, and the capacitance portions of the two resonance patterns are opposed to each other via a dielectric layer, so that the two resonance circuits are connected to each other. Join.

Further, on a part of the strip line of the resonance pattern, for example, on the other end side, the inductor portions are close to each other, inductively coupled to each other, and two resonant circuits are inductively coupled. This part to be inductively joined is called an inductive coupling part.

Further, the inductive coupling part of one strip line extends in the same direction as the direction in which the capacitance component of the coupling capacitance fluctuates due to displacement of the capacitance part, and the inductive coupling part of one strip line is connected to the other strip. It extends to the track side.

For example, when a displacement occurs such that the two strip lines are relatively separated from each other, the facing region between the two capacitance portions decreases. However, conversely, since the inductive coupling portion of one strip line extends to the other strip line side, if a positional displacement occurs in which the two are relatively separated, this inductive coupling portion The length of the part increases.

As a result, even if the capacitive coupling component decreases, the inductive coupling portion increases, and the variation in the overall coupling degree can be effectively suppressed.

Conversely, when a displacement occurs such that the two strip lines are relatively close to each other, the opposing portions of the two capacitance portions tend to increase, but conversely, the two strip lines have similar induction. The joint length is shortened,
Inductive coupling tends to decrease. As a result, it is possible to effectively suppress the variation of the entire coupling degree.

The other ends of the two inductors are connected to each other, and are connected to the ground potential by connection means such as via-hole conductors. Therefore, a common inductance component can be formed between the inductance component of the two resonance circuits and the ground potential by a connection means such as a via-hole conductor.

Thus, it is possible to easily form the inductance component L of the filter of the equivalent circuit shown in FIG. 3 which simultaneously performs the capacitive coupling and the inductive coupling. As a result, it is necessary to increase the size of the inductive coupling portion L32 in FIG. Therefore, a sufficient coupling between the two resonance circuits can be obtained. That is, it is possible to avoid an increase in the size of the slip line and to contribute to a reduction in the size of the entire multilayer filter.

In the present invention, the description will be made with reference to the equivalent circuit diagram of FIG. 3. The two inductor components L1 and L2 are mainly constituted by an inductor portion (strip line) substantially having a resonance pattern, and are commonly connected. The obtained inductance component L is composed of the above-described inductance component of the strip line, the inductance component of the inductive coupling portion, and the inductance component of the connection means such as the via-hole conductor. In practice, the inductance component of the strip line is distributed to the inductance components L1, L2, L at a certain ratio, and the structure and the equivalent circuit do not correspond one-to-one.

As described above, in forming the multilayer filter of the present invention, the change in the capacitance component of the coupling capacitance due to the displacement is as follows:
Since the fluctuation of the inductance component in the inductive coupling can be canceled each other, it can be effectively suppressed.

At the same time, the increase in the size of the inductive coupling shown in FIG. 8 can be effectively achieved by adding an inductance component L by means of connection means such as a via-hole conductor to the other end of the two strip lines in the present invention. Thus, the size of the strip line can be reduced.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laminated filter according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view mainly showing a conductor film of a multilayer filter of the present invention. FIG. 2 is a diagram showing the relationship of the conductive films when viewed from the upper surface side of the multilayer filter of the present invention, and FIG. 3 is an equivalent circuit diagram of the multilayer filter of the present invention.

According to the present invention, the laminated substrate is constituted by laminating, for example, seven dielectric layers.

In this laminate substrate, two equivalent L
Various conductor patterns 1 to 9 forming a C resonance circuit, and flat ground conductor layers 10 and 11 arranged to sandwich the resonance conductor patterns 1 to 9 from the upper surface side and the rear surface side.
It is composed of

As the dielectric layer, as the dielectric material, the strip lines 3 and 4 can be realized with an impedance close to 50Ω among various built-in conductor patterns and the strip lines 3 and 4 which are resonance patterns can be miniaturized. In order to achieve higher performance and higher performance, a material having a relative dielectric constant of 10 to 20 and having a high Q value and a τf close to 0 is selected.

For example, aMgO.bCaO.cTiO ₂
(25 ≦ a ≦ 35, 0.3 ≦ b ≦ 7, 60 ≦ c ≦ 70,
a + b + c = 100 weight ratio)
₃ to 20 parts by weight in terms of ₂ O ₃ , lithium-containing compound is L
Examples of the dielectric material include 1 to 10 parts by weight in terms of i ₂ O ₃ . The firing temperature for forming the dielectric layer is 900
The material is fired at a low temperature of about 1000 ° C.

Various conductor patterns including a resonance pattern (capacitance portion, strip line) formed inside the multilayer substrate are made of copper, silver, or copper, so as not to deteriorate the conductor loss.
It is formed using a low-resistance conductor such as gold. Moreover, since the co-firing with the laminated substrate is formed, it can be manufactured efficiently.

A ground conductor layer 10 on the upper surface of a flat plate is disposed between the first layer and the second layer between the dielectric layers of the laminated substrate.

The input / output electrode patterns 1 and 2 on the upper surface are formed between the second layer and the third layer.

Further, a capacitance portion 5 and an inductor portion (strip line) 3 as a first resonance pattern are formed between the third layer and the fourth layer. In addition, strip line 3
Has a narrow conductor width and substantially has a resonance circuit R
1 mainly constitutes the inductance component L1. For example, in FIG.
In FIG. 2, it is formed so as to be located on the lower side.

Further, between the fourth layer and the fifth layer, a capacitor section 6 and an inductor section (strip line) 4 as a second resonance pattern are formed. In addition, strip line 4
Substantially constitutes the inductance component L2 of the resonance circuit R2. For example, in FIG. 1, it is formed so as to be located on the upper side in FIG.

Between the fifth layer and the sixth layer, the lower input / output electrode pattern 7, which is connected to the input / output electrode patterns 1 and 2,
8 and a ground-side routing pattern 9 are formed.

A lower flat second ground conductor layer 11 is formed between the sixth and seventh layers.

Here, the resonance pattern will be described. In this embodiment, since the conductor width is narrow in the shape of the strip lines 3 and 4 and the conductor is separated from the ground potential,
It can be substantially regarded as an inductor part. It should be noted that the inductance component and the capacitance component may be simultaneously achieved in a distributed manner from the relationship between the shape and the ground potential.

The first resonance pattern shown in FIG. 1 includes a capacitance section 5 and a strip line (inductor section) 3. Further, the second resonance pattern includes the capacitance section 6 and the inductor section 4.

The strip lines 3 and 4 have a C-shape as a whole, and are arranged so that the two strip lines 3 and 4 are open to each other in a plane.

The first resonance pattern includes a substantially rectangular capacitor portion 5 from the other end side, a connecting portion 31 and a linear first inductor portion 32 along the pattern of the strip line 3, A second linear inductor section 33 bent from the first strip line 32 and extending to the other strip line 4 side, and a linear second inductor section bent from the second inductor section 33 to the capacitor section 5 side. 3 and a via-hole conductor land 35.

The second resonance pattern includes a substantially rectangular capacitor 6 and a strip line 4 from the other end.
Connection portion 41, a linear first inductor portion 42, and a linear second inductor portion 43 bent from the first strip line 42 and extending toward one of the strip lines 3 according to the following pattern. , The second inductor section 43
And a third linear inductor portion 44 and a via-hole conductor land portion 45 which are bent and extended to the side of the capacitor portion 6.

As described above, the two strip lines 3, 4
Are opposed to each other via the fourth dielectric layer, and the via-hole conductor lands 35 and 45 of the strip lines 3 and 4 are connected to the via-hole conductor 7 (via-hole conductor) penetrating the fourth dielectric layer. 7 penetrates the fifth layer in addition to the fourth layer)
Connected by

That is, the capacitive coupling component C of the two resonance circuits is mainly formed at the overlapping portion (indicated by the hatched area X in FIG. 2) of the capacitance portions 5 and 6 (the capacitance coupling portion is denoted by X).

In the shape of the substantially rectangular capacitor portion 5 and the shape of the capacitor portion 6, the shape of the capacitor portion 6 is slightly larger in one direction, for example, in the left-right direction in FIG. It has a shape. The difference is, for example, generally, a displacement of about 50 μm occurs in the lamination forming step, but the shape of the capacitance portion 6 is adjusted in one direction, that is, in FIG. It is getting bigger.

The other direction, that is, the vertical direction in FIG. 2, has substantially the same dimensions. Thus, even if a displacement in one direction occurs, the coupling capacitance component does not fluctuate, but if a displacement occurs in the other method, the area facing the capacitance portions 5 and 6 increases and decreases, and the capacitance junction component increases. C will fluctuate.

The second inductor portions 33 and 43 of the strip lines 3 and 4 are close to or opposed to each other (shown by oblique lines Y in FIG. 2) via a fourth dielectric layer. Thereby, a part of both inductor parts 33 and 43 becomes an inductive coupling part Y. More specifically, the inductive coupling portion Y is a part of the second inductor portions 33 and 43 and is near a bent portion with the third inductor portions 34 and 44.

Thus, the inductive coupling portion Y between the strip line 3 and the strip line 4 is formed in the direction in which the respective second inductor portions 33 and 43 extend. The inductive coupling portion Y is formed at a position where the capacitance component C of the coupling capacitance extends in the same direction as the fluctuation direction, that is, in the vertical direction on the paper of FIG.

The upper input / output pattern 1 is connected to the lower input / output pattern 7 via the connection portion 31 of the strip line 3 via the via-hole conductor 12.
Further, the upper input / output pattern 2 is connected to the lower input / output pattern 8 via the connection portion 41 of the strip line 4 described above.

Then, on the first resonance circuit R1 side of the equivalent circuit of FIG. 3, a capacitance component is generated between the upper input / output pattern 1 and the conductor layer 10 at the ground potential, and the lower input / output pattern 7 A capacitance component is generated between the ground and the conductor layer 11 at the ground potential, and becomes the synthesized capacitance component C1. Further, the inductance component L1 is mainly due to the strip line 3
, Thereby forming an LC resonance circuit.
Further, on the second resonance circuit R2 side, a capacitance component is generated between the upper input / output pattern 2 and the ground potential conductor layer 10, and the lower input / output pattern 8 and the ground potential conductor layer 11 A capacitance component is generated in between, and becomes the combined capacitance component C2. The inductance component L1 is
It is mainly composed of the strip line 4, whereby an LC resonance circuit is composed.

As described above, the inductance components L1 and L2 of the two resonance circuits R1 and R2 are connected to the ground potential by the common inductance component L.

The inductance component L on the equivalent circuit in FIG. 3 is a part of the inductance components of the strip lines 3 and 4, the via-hole conductors 14 and 15, and the routing electrode 9.
, And an inductance component of the inductive coupling portion Y.

As described above, in the multilayer filter of the present invention, the two resonance circuits R1 and R2 are mainly coupled, and furthermore, inductively coupled at the inductive coupling portion Y. That is, the equivalent circuit shown in FIG. 3 is obtained by performing B-Δ conversion from the equivalent circuit of FIG. 8 in which the capacitive coupling and the inductive coupling are arranged in parallel.

Thus, even if the inductance component L32 for performing inductive coupling is small as shown in FIG.
Inductance obtained by connection means (via hole conductor, wiring pattern 9 and via hole conductor 15) including land portions 35 and 45 of strip lines 3 and 4 and via hole conductor 14 connected to ground potential so as to complement inductive coupling. The components are arranged.

Therefore, even if the strip lines 3 and 4 are inductively coupled to each other and the inductance component is small, sufficient inductive coupling can be obtained, and at the same time, the size of the strip lines 3 and 4 can be avoided.

In the above-described planar positional relationship of the structure of the strip lines 3 and 4 of the multilayer filter, if one direction, for example, the left and right direction in FIG.
Even if a displacement of about μm occurs, the displacement can be absorbed by the dimensional difference between the capacitance section 5 of the strip line 3 and the capacitance section 6 of the strip line 4. That is, the capacitance component C that performs capacitive coupling does not change. At the same time, the second inductor portions 33 of the strip lines 3 and 4
In a part of 43, the distance between the adjacent components changes, but the variation of the inductance component of the inductive coupling portion Y is small.

That is, even if there is such a displacement, the capacitance component of the coupling capacitance and the inductance component to be inductively coupled do not substantially change, so that the two resonance circuits R1 and R2
Does not change, and stable filter characteristics can be maintained.

Next, a case where a displacement has occurred in the other direction, that is, in the vertical direction of FIG. 2, will be described with reference to FIG.

For example, FIG. 4A shows a state in which the strip lines 3, 4 are displaced relative to each other as indicated by arrows.

In this case, the capacitance portion 5 of the first resonance pattern
Then, the region X facing the capacitance portion 6 of the second resonance pattern decreases, and the capacitance component C of capacitive coupling decreases.

At the same time, the length of the inductive coupling portion Y indicated by oblique lines becomes longer due to the displacement. This is because the inductive coupling portion Y is formed so as to extend in the same direction as the direction in which the coupling capacitance component C fluctuates due to the displacement, and, for example, the inductive coupling portion of one of the strip lines 3 is
This is because it is formed to extend to the other strip line 4 side.

As described above, in the coupling capacitance component C, although the facing area between the capacitance portions 5 and 6 decreases, the inductance component of the inductive coupling increases conversely. Thus, the two are offset, and the variation in the coupling degree can be effectively suppressed.

Next, in FIG. 4B, as indicated by the arrow,
This shows a state in which the two strip lines 3 and 4 are displaced in a direction of relatively approaching.

In this case, the capacitance portion 5 of the first resonance pattern
And the capacitance region 6 of the second resonance pattern, the opposing region X thereof increases.

As a result, the coupling capacitance component C on the equivalent circuit shown in FIG. 3 increases. At the same time, the length of the inductive coupling portion Y indicated by oblique lines in FIG.

As described above, due to the displacement in one direction (the vertical direction on the paper surface of FIG. 2), the coupling capacitance component C causes the opposing region X between the capacitance portions 5 and 6 to increase and decrease, and at the same time, to increase the strip line 3 and The four inductive coupling portions Y also increase and decrease.
However, since both increasing and decreasing directions are opposite to each other,
From the viewpoint of the overall coupling degree, the two are offset, and the fluctuation of the coupling degree can be effectively suppressed.

The present inventor examined the characteristics of each of the bandpass type multilayer filter having the structure shown in FIG. 1 and the multilayer filter having no displacement in the multilayer filter having only the capacitance junction. FIG. 5 shows the characteristics of the multilayer filter of the present invention, wherein (a) shows the reflection loss and the passing loss,
(B) shows a pass loss near the pass band. 6A and 6B show the characteristics of the multilayer filter having only the capacitive coupling. FIG. 6A shows the reflection loss and the passing loss, and FIG. 6B shows the passing loss near the pass band. The reflection loss is generally called S11, which is the ratio of the reflected signal to the input signal, and the passing loss is generally called S21, and indicates the ratio of the output signal to the input signal.

In FIG. 5 and FIG. 6, the reflection loss characteristic lines r1 and r4 and the passage loss characteristic lines t1 and t4 are characteristics in a state where no displacement occurs.

In FIG. 5A, when a displacement of 50 μm occurs in the direction shown in FIG. 4A, the reflection loss r2 and the passing loss t2 are changed to the reflection loss characteristic line r1 and the passing loss characteristic line t1. No significant change was seen in comparison. When a displacement of 50 μm occurs in the direction in FIG. 4B, the reflection loss r3 and the passage loss t3 do not show a large change compared to the reflection loss characteristic line r1 and the passage loss characteristic line t1. Was.

In FIG. 6, when a displacement occurs in the same direction, the reflection characteristic r when no displacement occurs.
4. Compared with the pass characteristic t4, the respective reflection characteristics r5 and r
6. Pass characteristics t5 and t6 fluctuate greatly.

The band-pass filter is a multilayer filter formed using a low-temperature fired multilayer ceramic substrate (relative permittivity 15).

As can be clearly understood from a comparison between FIG. 5 and FIG. 6, in the multilayer filter of the present invention, even if a positional shift such as a stack shift or a print shift occurs in the resonance pattern, the filter characteristic is substantially reduced. There is no significant change.

In particular, as shown in FIGS. 5B and 6B,
As shown in the enlarged view near the pass band, in the cut-off frequency (frequency band of −3 dB) which is a measure of the pass band characteristic, the multilayer filter of the present invention can suppress the fluctuation to less than 100 MHz, but the conventional multilayer filter has In the filter, a fluctuation of about 300 MHz was observed.

[0086]

According to the multilayer filter of the present invention, even if a positional shift such as a stacking shift or a printing shift at the time of forming a multi-layer substrate, which is greatly affected by miniaturization of the element, a change in filter characteristics can be effectively prevented. Can be suppressed.

For this reason, it is possible to increase the frequency, employ a high dielectric constant substrate, and reduce the thickness of the dielectric layer.

Further, since a common inductance component can be easily arranged between the ground potential and the inductance of the two resonance circuits, the length of the strip line can be reduced.

Thus, in combination with the above-described thinning of the dielectric layer, the size of the laminated substrate can be reduced.

As described above, according to the present invention, a multilayer substrate can be formed with high precision, and it is inexpensive and has stable filter characteristics.
The laminated filter can be further reduced in size.

[Brief description of the drawings]

FIG. 1 is a perspective view showing each conductor pattern constituting a multilayer filter of the present invention.

FIG. 2 is a schematic view showing a planar relationship between conductor patterns constituting a filter of the present invention.

FIG. 3 is an equivalent circuit diagram of the multilayer filter of the present invention.

FIGS. 4A and 4B are schematic diagrams showing a state of misalignment in the multilayer filter of the present invention, wherein FIG. 4A shows an arrangement when misalignment occurs such that both resonance patterns are separated from each other, and FIG.
Shows an arrangement in the case where a positional shift occurs such that both resonance patterns approach each other.

FIGS. 5A and 5B are graphs showing filter characteristics when a displacement occurs in the multilayer filter of the present invention, and FIG. 5A is a characteristic diagram showing a reflection loss and a passing loss at each displacement.
(B) is an enlarged characteristic diagram of a pass band portion.

6A and 6B are graphs showing filter characteristics when a displacement occurs in a multilayer filter including only capacitive coupling, where FIG. 6A is a characteristic diagram showing reflection loss and pass loss at each displacement, and FIG. FIG. 7 is an enlarged characteristic diagram of a pass band portion.

7A shows an equivalent circuit diagram of a conventional bandpass filter, FIG. 7B shows an equivalent circuit diagram of a bandpass filter having only capacitive coupling, and FIG. 7C shows a band having only inductive coupling. FIG. 3 shows an equivalent circuit diagram of a pass filter.

FIG. 8 is an equivalent circuit diagram of a bandpass filter in which capacitive coupling and inductive coupling are performed.

Claims (2)

[Claims] 1. A first resonance pattern comprising a capacitor portion and an inductor portion constituting a first resonance circuit, and a second resonance circuit formed on a laminate substrate formed by laminating a plurality of dielectric layers. A second resonance pattern comprising a capacitor portion and an inductor portion is disposed, and the capacitor portions of both resonance patterns are capacitively coupled to each other in the thickness direction of the dielectric layer, and a part of the inductor portion of both resonance patterns is formed. Wherein the coupling degree of the inductive coupling portions of the two resonance patterns is inversely proportional to the coupling degree of the capacitive coupling of the two resonance patterns. 2. The method according to claim 1, wherein the tip portions of the inductance portions of the two resonance patterns are connected to each other and connected to the ground potential by connection means including a via-hole conductor penetrating the dielectric layer. The multilayer filter according to claim 1.