JP2008278361A - Laminate type band pass filter and diplexer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate type band pass filter which can improve the attenuation characteristics of the filter without adding an attenuation circuit by independently controlling the frequencies of the attenuation poles, and a diplexer using the same. <P>SOLUTION: The laminate type band pass filter includes a plurality of first resonators adapted to resonate in a predetermined pass band and arranged in a laminate, the first resonators being electromagnetic field coupled to each other, each of the first resonators having an inductor conductor and a conductor to be capacitive-coupled to a grounding conductor, one first resonator and an input terminal or output terminal being connected by a circuit including at least one capacitor, electrodes on sides connected to the input terminal or output terminal each between two electrodes constituting a capacitor being opposed to the grounding conductor, a second resonator being composed of a very small inductor component that each electrode itself has and capacitive coupling each electrode and the grounding electrode, and the resonance frequency of the second resonator being set in a frequency band higher than the resonance frequency band of the first resonator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer bandpass filter that can be used in a microwave band and a diplexer using the same.

Conventionally, in a filter including a resonator formed by laminating a plurality of dielectric layers, a structure using a via hole as an inductor conductor of the resonator has been proposed.
Specifically, in Patent Document 1, a plurality of stacked dielectric layers, a plurality of inductors formed by via holes penetrating the plurality of dielectric layers in the thickness direction, and formed between the plurality of dielectric layers A plurality of capacitors formed between the capacitor electrodes, the inductor is provided in a direction orthogonal to the main surface of the capacitor electrode, the plurality of inductors and the plurality of capacitors are respectively connected in parallel, and the plurality of capacitors There has been proposed an LC filter in which a plurality of LC resonators are formed by an inductor and the plurality of capacitors, and the plurality of inductors of the plurality of LC resonators are electromagnetically coupled.

  In Patent Document 2, an input terminal and an output terminal, at least two LC resonators electrically connected between the input terminal and the output terminal, and between the input terminal and the LC resonator. An input-side LC trap circuit electrically connected to the output terminal, and an output-side LC trap circuit electrically connected between the output terminal and the LC resonator, and electrically connected to the input terminal A part of the inductor forming the LC resonator is shared as the inductor forming the input side LC trap circuit, and the part of the inductor forming the LC resonator electrically connected to the output terminal is the output side. A multilayer LC filter shared as an inductor forming an LC trap circuit has been proposed. This Patent Document 2 also discloses that the inductors of the LC resonator and the LC trap circuit are formed by via holes penetrating a plurality of dielectric layers in the thickness direction.

FIG. 12 is an exploded perspective view of the multilayer LC filter disclosed in Patent Document 2. As shown in FIG.
As shown in FIG. 12, the laminated LC filter 100 includes an insulator sheet 103 provided with a coupling capacitor conductor 110 on the surface, an insulator sheet 104 provided with resonator capacitor conductors 111 and 112, and an LC trap. Insulator sheets 106 and 107 having capacitor conductors 113, 114, 115 and 116 on the surface, insulator sheets 105 and 108 having inductor via holes 117b, 118b, 117e and 118e, respectively, and ground conductors 119 and 120 Are formed by insulator sheets 102 and 109 provided on the surface.
Inductor via holes 117a to 117e and 118a to 118e, which are resonator coil conductors, are connected in the stacking direction of the insulating sheets 102 to 109 to form resonator inductors L101 and L102 having a length of substantially λ / 4. The axial directions of the resonator inductors L101 and L102 are perpendicular to the surfaces of the insulating sheets 102 to 109.
In the insulator sheet 104, the lead-out portion 111a of the resonator capacitor conductor 111 is exposed on the left side of the sheet 104 and connected to the input terminal, and the lead-out portion 112a of the resonator capacitor conductor 112 is exposed on the right side of the sheet 104. Connected to the terminal.
FIG. 11 is an electrical equivalent circuit diagram of the multilayer LC filter 100 shown in FIG.
The resonator inductor L101 and the resonator capacitor C101 form a parallel resonance circuit and form an LC resonator Q101. The resonator inductor L102 and the resonator capacitor C102 form a parallel resonance circuit and form an LC resonator Q102. The LC resonators Q101 and Q102 are electrically connected to each other via a coupling capacitor C103 to form a two-stage bandpass filter. Further, a part L101a of the resonator inductor L101 and the LC trap capacitor C104 form an input side LC trap circuit T101. Similarly, a part L102a of the resonator inductor L102 and the LC trap capacitor C105 form an output side LC trap circuit T102.

Japanese Patent No. 3127792 Japanese Patent Laid-Open No. 2003-124769

As described above, the filters described in Patent Documents 1 and 2 use via holes as inductor conductors of the resonator. Since the cross-sectional area of the via hole is larger than the cross-sectional area of the stripline, it is possible to reduce the conductor loss and improve the insertion loss value.
However, in the filter of Patent Document 1, when a bandpass filter is configured using two resonators, if the coupling between the resonators is capacitive, it is magnetic (inductive) on the low band side of the passband. If there is, it is possible to generate one attenuation pole on the high band side of the pass band, but in order to generate two or more attenuation poles, a new attenuation circuit must be added. That is, there is a problem in that miniaturization is hindered because a space for forming an additional circuit must be secured.

Patent Document 2 proposes to newly add an attenuation circuit (trap circuit). In this trap circuit, the inductor electrode forming the LC parallel resonance circuit is shared with a part of the inductor electrode forming the λ / 4 resonator, and the connection electrode for forming the LC parallel resonance circuit is used as the capacitor forming layer for the resonator. The trap circuit can be added without increasing the printed conductor layer. However, in order to adjust the input / output impedance in this configuration, it is necessary to adjust the “electrical connection position” of the trap circuit electrically connected to the input / output terminal and the resonator. Specifically, it is necessary to adjust the positions in the stacking direction of the lead portions 111a and 112a in FIG. 12, and it is not necessarily optimal to arrange them in the same layer as the capacitor forming layer for the resonator. There is a problem that a layer for printing the electrode has to be added, which hinders downsizing.
The present invention provides a multilayer bandpass capable of generating a new attenuation pole without adding an attenuation circuit and improving the attenuation characteristics of the filter by independently controlling the frequency of the attenuation pole. An object of the present invention is to provide a filter and a diplexer using the filter.

In order to achieve the above object, a multilayer bandpass filter according to the present invention includes a plurality of first resonators that resonate in a desired pass band inside a multilayer body, and the first resonators. Each of the first resonators includes an inductor conductor and a conductor capacitively coupled to the ground conductor, and at least one of the first resonators and the input terminal are at least one of the first resonator and the input terminal. Connected by a circuit including one capacitor, the other of the first resonators and the output terminal are connected by a circuit including at least one capacitor, and an input terminal or an output terminal of two electrodes constituting each capacitor; Each electrode to be connected is opposed to a ground conductor, and the second resonator is configured by a small inductor component of each electrode itself and capacitive coupling between each electrode and the ground conductor. The resonance frequency of the second resonator, and wherein the set than the resonance frequency of the first resonator in the high frequency side.
Further, according to the present invention, in a diplexer formed by a filter having a first passband and a filter having a second passband, one or both of the two filters are A diplexer comprising a bandpass filter may be provided.

The multilayer bandpass filter according to the present invention includes a plurality of first resonators that resonate in a desired pass band, and a band formed by electromagnetically coupling the first resonators to each other. In the pass filter, each first resonator includes an inductor conductor and a conductor capacitively coupled to a ground conductor, and one of the first resonators and an input terminal are connected by a circuit including at least one capacitor. The other end of the first resonator and the output terminal are connected by a circuit including at least one capacitor, and the electrodes on the side connected to the input terminal or the output terminal of the two electrodes constituting each capacitor are respectively grounded conductors. The second resonator is constituted by a small inductor component of each electrode itself and capacitive coupling between each electrode and the ground conductor, and the resonance frequency of the second resonator The set than the resonance frequency of the first resonator in the high frequency side.
With the above-described configuration, the desired passband that causes resonance is adjusted by the elements constituting the first resonator, and the attenuation pole on the higher frequency side than the resonance frequency of the first resonator is the second resonator. It is adjusted by the element which comprises.
Here, the second resonator has a ground conductor on each of the electrodes connected to the input terminal or the output terminal in the two electrodes constituting the capacitor for connecting the first resonator to the input terminal and the output terminal, respectively. Since each of the electrodes has a small inductor component and capacitive coupling between each electrode and the ground conductor, a new attenuation circuit is not added. Does not affect the size of.
The resonance frequency of the second resonator can be changed by changing the shape of the electrode connected to the input / output terminal while keeping the capacitor capacity of the input / output coupling capacitor constant. The resonance frequency of the second resonator can be adjusted without affecting the passband characteristics. That is, the desired passband characteristics by the first resonator and the frequency of the attenuation pole by the second resonator can be adjusted independently, so that the high-band side attenuation characteristics are excellent and the design A band-pass filter having a high degree of freedom can be provided.
Furthermore, in a diplexer comprising a filter having a first passband and a filter having a second passband, one or both of the two filters is the bandpass filter. Thus, a diplexer having excellent attenuation characteristics can be provided.

Hereinafter, embodiments of the present invention will be described with reference to some examples shown in the accompanying drawings.
FIG. 1 is a diagram schematically showing a circuit configuration of an embodiment of a bandpass filter according to the present invention.
As shown in FIG. 1, this band pass filter includes four resonators.
The resonator R1 includes a capacitor C11 and resonant elements L11 and L12, and constitutes one of the first resonators.
The resonator R2 includes a capacitor C21 and resonance elements L21 and L22, and constitutes the other of the first resonators.
The resonator R3 is a capacitor formed by making an electrode (shared electrode) on the input terminal IN side of a pair of electrodes forming the capacitor C12 connected between the resonator R1 and the input terminal IN face a ground electrode. C13 and a small inductor component L13 possessed by the shared electrode itself, which is caused by distributed constant behavior that cannot be ignored as the frequency becomes higher, and constitutes one of the second resonators.
The resonator R4 is a capacitor formed by making an electrode (shared electrode) on the output terminal OUT side of a pair of electrodes forming a capacitor C22 connected between the resonator R2 and the output terminal OUT face a ground electrode. C23 and a small inductor component L23 of the shared electrode itself, which is generated by distributed constant behavior that cannot be ignored as the frequency becomes higher, and constitutes the other of the second resonators. In general, the higher the frequency of the signal to be used, that is, the shorter the wavelength, the more the influence of the size and shape of the electrodes constituting the capacitor, inductor, ground, etc. must be considered. For example, in the case of a strip line formed in a dielectric layer having a dielectric constant of 15, a quarter wavelength at a frequency of 10 GHz is 1.94 mm. For example, a capacitor electrode having a size of about 2 mm is used as a capacitor electrode. In addition to functioning as a resonance electrode. The second resonators R3 and R4 utilize such a phenomenon peculiar to a high frequency, and the effect as a resonator is obtained by using the minute inductor component of the capacitor electrode itself and the original capacitance component of the capacitor. .
In addition, in a small electronic component having an outer size of approximately 2.5 mm × 2.0 mm or less, such as a filter component, used in a wireless communication device, the influence is remarkable in a frequency region that is approximately twice or more the passband. For this reason, the present invention is particularly effective in a filter component for a 5 GHz band used in, for example, a wireless run.
The connection point of the resonance elements L11 and L12 in the first resonator R1 is connected to the input terminal IN via the capacitor C12, and between the resonance elements L21 and L22 in the second resonator R2 via the capacitor C31. It is also connected to the connection point. The connection point between the resonant elements L21 and L22 is also connected to the output terminal OUT via the capacitor C22.
In addition, the resonant element L11 and the capacitor C11 in the first resonator R1 are each grounded. The resonant element L21 and the capacitor C21 in the second resonator R2 are each grounded.
1 indicates inductive coupling between the resonant elements L11 and L21 and between the resonant elements L12 and L22, and the size thereof can be set according to the interval between the resonant elements.
The bandpass filter configured as described above is set so that the first resonators R1 and R2 resonate in a desired passband, and the second resonators R3 and R4 are connected to the first resonators R1 and R2. It is set to resonate at a higher frequency side than the resonance frequency to generate an attenuation pole.

With the circuit configuration described above, the desired passband that causes resonance is adjusted by the elements constituting the first resonators R1 and R2, and the attenuation pole on the higher frequency side than the resonance frequency of the first resonators R1 and R2 is It is adjusted by the elements constituting the second resonators R3 and R4.
Here, in the second resonators R3 and R4, one of the electrodes constituting the capacitors C12 and C22 for connecting the first resonators R1 and R2 to the input terminal IN and the output terminal OUT is opposed to the ground electrode. Since it is configured by arranging, a new attenuation circuit is not added and the size of the bandpass filter is not affected.
The resonance frequency of the second resonators R3 and R4 can be changed by changing the shape of the electrodes connected to the input / output terminals IN and OUT while keeping the capacitance of the input / output coupling capacitors C12 and C22 constant. Therefore, the resonance frequencies of the second resonators R3 and R4 can be adjusted without affecting the passband characteristics as a bandpass filter.
That is, since the desired passband characteristic by the first resonators R1 and R2 and the frequency of the attenuation pole by the second resonators R3 and R4 can be independently adjusted, the attenuation characteristic on the high band side is excellent. In addition, a bandpass filter having a high degree of design freedom can be provided.

Several specific examples of the multilayer bandpass filter that realizes the circuit configuration described above will be described below.
FIG. 2 is a perspective view of the appearance of an embodiment of a multilayer bandpass filter that realizes the circuit configuration shown in FIG.
This band-pass filter is composed of a multilayer substrate in which six dielectric layers M1 to M6 are laminated, and has dimensions of about 2.0 mm in length, about 2.5 mm in width, and about 0.85 mm in height.
In FIG. 2, symbols T1 and T2 indicate ground terminals, symbol IN indicates an input terminal, and symbol OUT indicates an output terminal.
3 is a schematic plan view of each dielectric layer constituting the band-pass filter shown in FIG. 2, and FIG. 4 is an exploded perspective view of the band-pass filter shown in FIG.
The dielectric layers M1, M3, M5, and M6 are made of a material having a relatively low dielectric constant (eg, dielectric constant ε7), and the dielectric layers M2 and M4 are relatively high in dielectric constant (eg, dielectric constant ε15). ) Consists of materials.
Three cutout recesses are formed in a pair of opposed side portions of each dielectric layer M1 to M6. In these recesses, ground terminals T1 and T2, an input terminal IN, and an output terminal OUT are formed. In addition, you may form each terminal by side printing etc., without providing a notch recessed part.

Hereinafter, the configuration of each of the dielectric layers M1 to M6 will be described in detail.
A ground electrode 1 connected to the ground terminals T1 and T2 is formed on the lowermost dielectric layer M1.
On the second dielectric layer M2, one electrode 2 of the capacitor C11 that forms the resonator R1 and one electrode 3 of the capacitor C21 that forms the resonator R2 are formed.
The other electrodes of the capacitors C11 and C21 are formed by corresponding portions 2 ′ and 3 ′ of the ground electrode 1 in the dielectric layer M1, respectively.

On the third dielectric layer M3, one electrodes 4, 5 and 6 of capacitors C12, C22 and C31 are formed, and on the fourth dielectric layer M4, capacitors C12, C22 and C31. The other electrodes 4 ', 5' and 6 'are formed.
Thereby, the capacitors C12, C22, and C31 are connected in series.
The electrode 4 forming one electrode of the capacitor C12 in the third dielectric layer M3 is connected to the input terminal IN. The electrode 5 forming one electrode of the capacitor C22 in the same layer M3 is connected to the output terminal OUT.
A ground electrode 7 connected to the ground terminals T1 and T2 is formed on the fifth dielectric layer M5.

The electrode 4 forming one electrode of the capacitor C12 formed on the third dielectric layer M3 is opposed to the ground electrode 1 formed on the dielectric layer M1. As a result, a capacitor C13 is formed by capacitive coupling between the electrode 4 and the ground electrode 1. Here, since the electrode 4 itself has the minute inductor component L13, the LC series resonator R3 is formed between the electrode 4 and the ground electrode 1.
The electrode 5 forming one electrode of the capacitor C22 formed on the third dielectric layer M3 is opposed to the ground electrode 1 formed on the dielectric layer M1. As a result, a capacitor C23 is formed by capacitive coupling between the electrode 5 and the ground electrode 1. Here, since the electrode 5 itself has a small inductor component L 23, an LC series resonator R 4 is formed between the electrode 5 and the ground electrode 1.

In the dielectric layers M3, M4, and M5, via conductors that form a resonant element are formed. Here, the via conductor is formed by forming a columnar conductive material in a through hole (via hole) provided in the dielectric layer, or by providing a conductive material along the inner wall of the through hole, A conductive path for electrically connecting dielectric layers.
3 and 4, reference numerals 8 and 9 denote via conductors formed in the dielectric layer M3, reference numerals 10 and 11 denote via conductors formed in the dielectric layer M4, and reference numerals 12 and 13 denote The via conductor currently formed in the dielectric material layer M5 is shown.
The via conductor 8 formed in the dielectric layer M3 passes through the dielectric layer M3, and its upper end is connected to one electrode 6 forming the capacitor C31, and its lower end is one electrode 2 forming the capacitor C11. It is connected to the.
The via conductor 9 formed in the dielectric layer M3 passes through the dielectric layer M3, and its lower end is connected to one electrode 3 forming the capacitor C21.
The via conductor 10 formed in the dielectric layer M4 passes through the dielectric layer M4, the upper end thereof is connected to the other electrode 4 ′ forming the capacitor C12, and the lower end thereof is one electrode forming the capacitor C31. 6 is connected to the via conductor 8 of the dielectric layer M3.
The via conductor 11 formed in the dielectric layer M4 passes through the dielectric layer M4, and its upper end is connected to the other electrode 5 ′ forming the capacitor C22 and the other electrode 6 ′ forming the capacitor C31. The lower end is connected to the via conductor 9 of the dielectric layer M3.
The via conductor 12 formed in the dielectric layer M5 passes through the dielectric layer M5, the upper end thereof is connected to the ground electrode 7, and the lower end thereof is passed through the other electrode 4 ′ forming the capacitor C12, and the dielectric layer M4. Are connected to the via conductor 10.
The via conductor 13 formed in the dielectric layer M5 penetrates the dielectric layer M5, the upper end thereof is connected to the ground electrode 7, and the lower end thereof forms the other electrode 5 ′ and the capacitor C31 that form the capacitor C22. The other electrode 6 'is connected to the via conductor 11 of the dielectric layer M4.
With the above-described configuration, one resonant element L1 is formed by the via conductors 8, 10 and 12 and the electrode 2 forming the capacitor C11, and one resonant element is formed by the via conductors 9, 11 and 13 and the electrode 3 forming the capacitor C21. L2 is formed.
The axial directions of the two resonant elements L1 and L2 are perpendicular to the surfaces of the dielectric layers M1 to M6, and when a current flows through the resonant elements L1 and L2, the resonant elements are disposed around the resonant elements L1 and L2. A magnetic field that circulates in a plane perpendicular to the axial direction of is generated.
One resonant element L1 formed by the via conductors 8, 10 and 12 and the electrode 2 forming the capacitor C11 is a resonance composed of the via conductors 8 and 10 by the electrodes 4, 4 'and 6 forming the capacitors C12 and C31. An intermediate tap is formed between the part of the element L12 and the part of the resonant element L11 made of the via conductor 12.
The other resonant element L2 formed by the via conductors 9, 11 and 13 and the electrode 3 forming the capacitor C21 is connected to the via conductors 9 and 11 by the electrodes 5, 5 'and 6' forming the capacitors C22 and C31. An intermediate tap is formed between the portion of the resonant element L22 made of and the portion of the resonant element L21 made of the via conductor 13.

In the multilayer bandpass filter configured as described above, the resonance frequency of the first resonators R1 and R2 is that of the inductor formed by the via holes 8 to 13 formed in the dielectric layers M3, M4, and M5. It can be adjusted by changing the size. Specifically, the size of the inductor can be adjusted by the thickness of the multilayer bandpass filter. The resonance frequency can be adjusted by changing the capacitances of the capacitors C11 and C21. Specifically, the capacitances of the capacitors C11 and C21 can be adjusted by the size of the electrodes 2 and 3 in the dielectric layer M2. It can also be adjusted by changing the thickness of the dielectric layer M2.
On the other hand, the second resonators R3 and R4 are set so as to resonate at a higher frequency side than the resonance frequency of the first resonators R1 and R2, and the electrode 4 and the capacitor C23 that form the capacitor C13 and the inductor L13. And the shape of the electrode 5 forming the inductor L23 is adjusted by changing so as not to affect the capacitance of the capacitors C12 and C22, respectively.
As described above, the resonance frequencies of the second resonators R3 and R4 can be adjusted independently without affecting the resonance frequencies of the first resonators R1 and R2.

2 to 4, the thickness of the dielectric layer M1 is 0.06 mm, the thickness of the dielectric layer M2 is 0.019 mm, the thickness of the dielectric layer M3 is 0.03 mm, and the thickness of the dielectric layer M4 The thickness is 0.019 mm, the thickness of the dielectric layer M5 is 0.549 mm, and the thickness of the dielectric layer M6 is 0.03 mm.
FIG. 5A is a graph showing the electrical characteristics of a conventional multilayer bandpass filter that does not have a series resonator for generating an attenuation pole, and FIG. 5B is shown in FIGS. 5 is a graph showing electrical characteristics of the multilayer bandpass filter according to the present invention.
As shown in FIG. 5A, in the conventional bandpass filter, an attenuation pole is generated only in the frequency band of 8 GHz.
On the other hand, in the multilayer bandpass filter according to the present invention, an attenuation pole is generated due to the coupling between the resonators of the first resonators R1 and R2 in the frequency band of 8 GHz, and the vicinity of 14 GHz higher than that. It can be seen from FIG. 5B that attenuation poles are generated by the second resonators R3 and R4 in the frequency band.

Next, with reference to FIGS. 6 and 7, a second embodiment of the multilayer bandpass filter that realizes the circuit configuration shown in FIG. 1 will be described.
6 is a schematic plan view of each dielectric layer of the second embodiment of the multilayer bandpass filter realizing the circuit configuration shown in FIG. 1, and FIG. 7 is an exploded perspective view of the bandpass filter shown in FIG. Each is shown.
As shown in the drawing, this multilayer bandpass filter is composed of seven dielectric layers M11 to M17.
Here, the dielectric layers M11, M13, M16, and M17 are made of a material having a relatively low dielectric constant (eg, dielectric constant ε7), and the dielectric layers M12, M14, and M15 are relatively high in dielectric constant ( For example, it is made of a dielectric constant ε15) material.
The thickness of the dielectric layer M11 is 0.06 mm, the thickness of the dielectric layer M12 is 0.019 mm, the thickness of the dielectric layer M13 is 0.03 mm, the thickness of the dielectric layer M14 is 0.019 mm, and the thickness of the dielectric layer M15. Is 0.019 mm, the thickness of the dielectric layer M16 is 0.50 mm, and the thickness of the dielectric layer M17 is 0.03 mm.
Three cutout recesses are formed in a pair of opposing side portions of each of the dielectric layers M11 to M17. In these recesses, ground terminals T21, T22, T23, an input terminal IN, and an output terminal OUT are formed. In addition, you may form each terminal by side printing etc., without providing a notch recessed part.

Hereinafter, the configuration of each of the dielectric layers M11 to M17 will be described in detail.
On the lowermost dielectric layer M11, a ground electrode 21 connected to the ground terminals T21, T22, and T23 is formed.
On the second dielectric layer M12, one electrode 22 of the capacitor C11 forming the resonator R1 and one electrode 23 of the capacitor C21 forming the resonator R2 are respectively formed.
The other electrodes of the capacitors C11 and C21 are respectively formed by corresponding portions 22 ′ and 23 ′ of the ground electrode 21 in the dielectric layer M11.

On the third dielectric layer M13, one electrodes 24 and 25 of the capacitors C12 and C22 are formed, and on the fourth dielectric layer M14, the other electrodes 24 ′ and 24 ′ of the capacitors C12 and C22 are formed. 25 'is formed.
The electrode 24 forming one electrode of the capacitor C12 in the third dielectric layer M13 is connected to the input terminal IN. The electrode 25 forming one electrode of the capacitor C22 in the same layer M13 is connected to the output terminal OUT.
The fifth dielectric layer M15 is provided with an electrode 26 forming one electrode of the capacitor C31, and the sixth dielectric layer M16 is provided with a ground electrode 27 connected to the ground terminals T21 and T22. Is formed.
The other electrode of the capacitor C31 is formed by the other electrodes 24 ′ and 25 ′ of the capacitors C12 and C22 formed on the dielectric layer M14. As a result, the capacitors C12, C22, and C31 are connected in series.

The electrode 24 forming one electrode of the capacitor C12 formed on the third dielectric layer M13 is opposed to the ground electrode 21 formed on the dielectric layer M11. As a result, a capacitor C13 is formed by capacitive coupling between the electrode 24 and the ground electrode 21. Here, since the electrode 24 itself has a small inductor component L13, an LC series resonator R3 is formed between the electrode 24 and the ground electrode 21.
The electrode 25 forming one electrode of the capacitor C22 formed on the third dielectric layer M13 is opposed to the ground electrode 21 formed on the dielectric layer M11. Thereby, a capacitor C23 is formed by capacitive coupling between the electrode 25 and the ground electrode 21. Here, since the electrode 25 itself has a small inductor component L 23, an LC series resonator R 4 is formed between the electrode 25 and the ground electrode 21.

In the dielectric layers M13, M14, M15, and M16, via conductors that form resonant elements are formed.
6 and 7, reference numerals 28 and 29 denote via conductors formed in the dielectric layer M13, reference numerals 30 and 31 denote via conductors formed in the dielectric layer M14, and reference numerals 32 and 33 denote A via conductor formed in the dielectric layer M15 is shown, and reference numerals 34 and 35 denote via conductors formed in the dielectric layer M16.
The via conductor 28 formed in the dielectric layer M13 passes through the dielectric layer M13, and the lower end thereof is connected to one electrode 22 that forms the capacitor C11.
The via conductor 29 formed in the dielectric layer M13 penetrates the dielectric layer M13, and the lower end thereof is connected to one electrode 23 forming the capacitor C21.
The via conductor 30 formed in the dielectric layer M14 passes through the dielectric layer M14, and its upper end is connected to the other electrode 24 ′ forming the capacitor C12, and its lower end is the via conductor 28 of the dielectric layer M13. It is connected to the.
The via conductor 31 formed in the dielectric layer M14 passes through the dielectric layer M14, and its upper end is connected to the other electrode 25 ′ forming the capacitor C22, and its lower end is the via conductor 29 of the dielectric layer M13. It is connected to the.
The via conductor 32 formed in the dielectric layer M15 passes through the dielectric layer M15, and the lower end thereof is connected to the via conductor 30 of the dielectric layer M14 through the other electrode 24 ′ forming the capacitor C12.
The via conductor 33 formed in the dielectric layer M15 penetrates the dielectric layer M15, and the lower end thereof is connected to the via conductor 31 of the dielectric layer M14 through the other electrode 25 ′ forming the capacitor C22.
The via conductor 34 formed in the dielectric layer M16 passes through the dielectric layer M16, and has an upper end connected to the ground electrode 27 and a lower end connected to the via conductor 32 of the dielectric layer M15.
The via conductor 35 formed in the dielectric layer M16 passes through the dielectric layer M16, and has an upper end connected to the ground electrode 27 and a lower end connected to the via conductor 33 of the dielectric layer M15.
With the above-described configuration, one resonant element L1 is formed by one electrode 22 forming the via conductors 28, 30, 32 and 34 and the capacitor C11, and one via conductor 29, 31, 33 and 35 and the capacitor C21 are formed. One resonant element L2 is formed by the electrode 23.
The axial directions of the two resonance elements L1 and L2 are perpendicular to the surfaces of the dielectric layers M11 to M17. When a current flows through the resonance elements L1 and L2, the resonance elements L1 and L2 are surrounded by the resonance elements. A magnetic field that circulates in a plane perpendicular to the axial direction of is generated.
One resonant element L1 formed of the via conductors 28, 30, 32 and 34 and the one electrode 22 forming the capacitor C11 is connected to the via conductor 28 and the electrodes 24, 24 'and 26 forming the capacitors C12 and C31. An intermediate tap is formed between the portion of the resonant element L12 made of 30 and the portion of the resonant element L11 made of the via conductors 32 and 34.
The other resonant element L2 formed by the via conductors 29, 31, 33 and 35 and the one electrode 23 forming the capacitor C21 is connected to the via conductor by the electrodes 25, 25 ′ and 26 forming the capacitors C22 and C31. An intermediate tap is formed between the portion of the resonant element L22 composed of 29 and 31 and the portion of the resonant element L21 composed of the via conductors 33 and 35.

In the multilayer bandpass filter configured as described above, the resonance frequencies of the first resonators R1 and R2 are inductors configured by via holes 28 to 35 formed in the dielectric layers M13, M14, M15, and M16. Can be adjusted by changing the size of. Specifically, the size of the inductor can be adjusted by the thickness of the multilayer bandpass filter. The resonance frequency can be adjusted by changing the capacitances of the capacitors C11 and C12. Specifically, the capacitances of the capacitors C11 and C21 can be adjusted by the size of the electrodes 22 and 23 in the dielectric layer M12. It can also be adjusted by changing the thickness of the dielectric layer M12.
On the other hand, the second resonators R3 and R4 are set so as to resonate at a higher frequency side than the resonance frequency of the first resonators R1 and R2, and the capacitor 24 and the capacitor C23 that form the capacitor C13 and the inductor L13. And the shape of the electrode 25 forming the inductor L23 is adjusted by changing so as not to affect the capacitance of the capacitors C12 and C22.
As described above, the resonance frequencies of the second resonators R3 and R4 can be adjusted independently without affecting the resonance frequencies of the first resonators R1 and R2.

Next, a third embodiment of the multilayer bandpass filter that realizes the circuit configuration shown in FIG. 1 will be described with reference to FIGS.
FIG. 8 is a schematic plan view of each dielectric layer of the third embodiment of the multilayer bandpass filter realizing the circuit configuration shown in FIG. 1, and FIG. 9 is an exploded perspective view of the bandpass filter shown in FIG. Each is shown.
As shown in the drawing, this multilayer bandpass filter is composed of a multilayer substrate in which eight dielectric layers M21 to M28 are laminated, and has a vertical width of about 1.25 mm, a horizontal width of about 2.0 mm, and a height of about 0.2 mm. It has a dimension of 8 mm.
Here, the dielectric layers M21, M23, M27, and M28 are made of a material having a relatively low dielectric constant (for example, a dielectric constant ε7), and the dielectric layers M22, M24, M25, and M26 have a relative dielectric constant. It is composed of a high material (for example, dielectric constant ε15).
The dielectric layer M21 has a thickness of 0.06 mm, the dielectric layer M22 has a thickness of 0.019 mm, the dielectric layer M23 has a thickness of 0.03 mm, the dielectric layer M24 has a thickness of 0.019 mm, and the dielectric layer M25 has a thickness. Is 0.019 mm, the thickness of the dielectric layer M26 is 0.03 mm, the thickness of the dielectric layer M27 is 0.46 mm, and the thickness of the dielectric layer M28 is 0.03 mm.
Three cutout recesses are formed in each of the pair of opposing side portions of each of the dielectric layers M21 to M28. In these recesses, ground terminals T31 to T34, an input terminal IN, and an output terminal OUT are formed.

Hereinafter, the configuration of each of the dielectric layers M21 to M28 will be described in detail.
A ground electrode 41 connected to the ground terminals T31 to T34 is formed on the lowermost dielectric layer M21.
On the second dielectric layer M22, one electrode 42 of the capacitor C11 that forms the resonator R1 and one electrode 43 of the capacitor C21 that forms the resonator R2 are formed.
The other electrodes of the capacitors C11 and C21 are formed by corresponding portions 42 ′ and 43 ′ of the ground electrode 41 in the dielectric layer M21, respectively.

On the third dielectric layer M23, one electrodes 44 and 45 of the capacitors C12 and C22 are formed, and on the fourth dielectric layer M24, the other electrodes 44 ′ and 44 ′ of the capacitors C12 and C22 are formed. 45 'is formed.
The electrode 44 forming one electrode of the capacitor C12 in the third dielectric layer M23 is connected to the input terminal IN. The electrode 45 forming one electrode of the capacitor C22 in the same layer M23 is connected to the output terminal OUT.
The fifth dielectric layer M25 is provided with an electrode 46 that forms one electrode of the capacitor C31, and the sixth dielectric layer M26 is an electrode that forms part of the resonant elements L11 and L12. 47 and 48 are formed.
A ground electrode 49 connected to the ground terminals T31 to T34 is formed on the seventh dielectric layer M27.
The other electrode of the capacitor C31 is formed by the other electrodes 44 ′ and 45 ′ of the capacitors C12 and C22 formed on the dielectric layer M24. As a result, the capacitors C12, C22, and C31 are connected in series.

The electrode 44 forming one electrode of the capacitor C12 formed on the third dielectric layer M23 is opposed to the ground electrode 41 formed on the dielectric layer M21. Thereby, a capacitor C13 is formed by capacitive coupling between the electrode 44 and the ground electrode 41. Here, since the electrode 44 itself has the minute inductor component L13, the LC series resonator R3 is formed between the electrode 44 and the ground electrode 41.
The electrode 45 forming one electrode of the capacitor C22 formed on the third dielectric layer M23 faces the ground electrode 41 formed on the dielectric layer M21. As a result, a capacitor C23 is formed by capacitive coupling between the electrode 45 and the ground electrode 41. Here, since the electrode 45 itself has a small inductor component L 23, an LC series resonator R 4 is formed between the electrode 45 and the ground electrode 41.

The dielectric layers M23, M24, M25, M26, and M27 are formed with via conductors that form resonant elements.
8 and 9, reference numerals 50 and 51 denote via conductors formed in the dielectric layer M23, reference numerals 52 and 53 denote via conductors formed in the dielectric layer M24, and reference numerals 54 and 55 denote the via conductors. Reference numerals 56 and 57 denote via conductors formed in the dielectric layer M26, and reference numerals 58 and 59 denote via conductors formed in the dielectric layer M27. Show.
The via conductor 50 formed in the dielectric layer M23 penetrates the dielectric layer M23, and the lower end thereof is connected to one electrode 42 forming the capacitor C11.
The via conductor 51 formed in the dielectric layer M23 penetrates the dielectric layer M23, and the lower end thereof is connected to one electrode 43 that forms the capacitor C21.
The via conductor 52 formed in the dielectric layer M24 penetrates the dielectric layer M24, and the upper end thereof is connected to the other electrode 44 ′ forming the capacitor C12, and the lower end thereof is the via conductor 50 of the dielectric layer M23. It is connected to the.
The via conductor 53 formed in the dielectric layer M24 penetrates the dielectric layer M24, and its upper end is connected to the other electrode 45 ′ forming the capacitor C22, and its lower end is the via conductor 51 of the dielectric layer M23. It is connected to the.
The via conductor 54 formed in the dielectric layer M25 passes through the dielectric layer M25, and the lower end thereof is connected to the electrode 44 ′ of the dielectric layer M24.
The via conductor 55 formed in the dielectric layer M25 penetrates the dielectric layer M25, and the lower end thereof is connected to the electrode 45 ′ of the dielectric layer M24.
The via conductor 56 formed in the dielectric layer M26 passes through the dielectric layer M26, and its upper end is connected to the electrode 47 formed in the same layer M26, and its lower end is formed in the dielectric layer M25. Connected to conductor 54.
The via conductor 57 formed in the dielectric layer M26 penetrates the dielectric layer M26, and its upper end is connected to the electrode 48 formed in the same layer M26, and its lower end is formed in the dielectric layer M25. Connected to the conductor 55.
The via conductor 58 formed in the dielectric layer M27 passes through the dielectric layer M27, and has an upper end connected to the ground electrode 49 and a lower end connected to the electrode 47 of the dielectric layer M26.
The via conductor 59 formed in the dielectric layer M27 passes through the dielectric layer M27, and has an upper end connected to the ground electrode 49 and a lower end connected to the electrode 48 of the dielectric layer M26.
With the above configuration, one resonant element L1 is formed by the via conductors 50, 52, 54, 56, 58 and the electrodes 44 ′, 47, and the via conductors 51, 53, 55, 57, 59 and the electrodes 45 ′, 48 are formed. One resonant element L2 is formed.
The axial directions of the portions other than the electrodes 44 ′, 45 ′, 47, and 48 of the two resonance elements L1 and L2 are perpendicular to the surfaces of the dielectric layers M21 to M28, and current flows through the resonance elements L1 and L2. When flowing, a magnetic field that circulates around a plane perpendicular to the axial direction of the resonant element is generated around each resonant element L1, L2.
One resonant element L1 formed of the via conductors 50, 52, 54, 56, 58 and the electrodes 44 ′, 47 is connected to the via conductors 50, 52, and 46 by the electrodes 44, 44 ′, and 46 forming the capacitors C12 and C31. An intermediate tap is formed between the portion of the resonant element L12 formed of the electrode 44 ′ and the portion of the resonant element L11 formed of the via conductors 54, 56, and 58 and the electrode 47.
The other resonant element L2 formed by the via conductors 51, 53, 55, 57, 59 and the electrodes 45 ′, 48 is connected to the via conductors 51, 45 by the electrodes 45, 45 ′, and 46 forming the capacitors C22 and C31. An intermediate tap is formed between the portion of the resonant element L22 formed of 53 and the electrode 45 'and the portion of the resonant element L21 formed of the via conductors 55, 57, 59 and the electrode 48.

In the multilayer bandpass filter configured as described above, the resonance frequencies of the first resonators R1 and R2 are configured by via holes 51 to 59 formed in the dielectric layers M23, M24, M25, M26, and M27. It can be adjusted by changing the size of the inductor. Specifically, the size of the inductor can be adjusted by the thickness of the multilayer bandpass filter. Further, it can be adjusted by changing the shape and size of the electrodes 42 and 43 of the dielectric layer M22 and the electrodes 47 and 48 of the dielectric layer M26, that is, changing the size of the inductor. Furthermore, the resonance frequency can be adjusted by changing the capacitance of the capacitors C11 and C12. Specifically, the capacitances of the capacitors C11 and C12 can be adjusted by the size of the electrodes 42 and 43 in the dielectric layer M22. It can also be adjusted by changing the thickness of the dielectric layer M22.
On the other hand, the second resonators R3 and R4 are set so as to resonate at a higher frequency side than the resonance frequency of the first resonators R1 and R2, and the electrode 44 and the capacitor C23 forming the capacitor C13 and the inductor L13. And the shape of the electrode 45 forming the inductor L23 is adjusted by changing so as not to affect the capacitance of the capacitors C12 and C22, respectively.
As described above, the resonance frequencies of the second resonators R3 and R4 can be adjusted independently without affecting the resonance frequencies of the first resonators R1 and R2.
FIG. 10 shows the frequency characteristics of the multilayer bandpass filter when the dimensions of the electrodes 44 and 45 in the dielectric layer M23 are changed to 0.35 mm, 0.55 mm and 0.75 mm in the direction of the arrow.
From FIG. 10, it can be seen that the smaller the dimensions of the electrodes 44 and 45, the farther away the resonance frequencies of the second resonators R3 and R4 are on the high frequency side.
Further, from FIG. 10, when the dimensions of the electrodes 44 and 45 are changed, the resonance frequency of the second resonators R3 and R4 varies, but is generated by the resonance frequency of the passband and the electromagnetic coupling of the resonance elements L1 and L2. It can be seen that the frequency of the attenuation pole does not vary.
Thus, even if the dimensions of the electrodes 44 and 45 are changed and the resonance frequencies of the second resonators R3 and R4 are adjusted, the resonance frequency in the passband and the electromagnetic coupling between the resonance elements L1 and L2 occur. Since the frequency of the attenuation pole is not affected, the resonance frequencies of the second resonators R3 and R4 can be adjusted independently.

In the embodiments described above, a multilayer bandpass filter having one pass band is described as an example. However, according to the present invention, a bandpass filter having a first passband, In a diplexer formed by a bandpass filter having a pass band, it is possible to provide a diplexer having excellent attenuation characteristics on the high frequency side by forming either or both of them with the bandpass filter according to the present invention. it can.
Specifically, as the diplexer, as described above, both the bandpass filter having the first pass band and the bandpass filter having the second pass band are distributed constant types described in the above-described embodiments. As an example, a diplexer formed by the bandpass filter of FIG.
As another example, a band pass filter having a first pass band is formed by the distributed constant type band pass filter described in the above embodiment, and a band pass filter having a second pass band is formed by a lumped constant. A diplexer formed of a type of band-pass filter can be mentioned.

It is a figure which shows schematically the circuit structure of one Example of the band pass filter of this invention. FIG. 2 is a perspective view of the appearance of an embodiment of a multilayer bandpass filter that realizes the circuit configuration shown in FIG. 1. FIG. 3 is a schematic plan view of each dielectric layer constituting the bandpass filter shown in FIG. 2. It is a disassembled perspective view of the band pass filter shown in FIG. (A) is a graph which shows the electrical property of the conventional laminated type band pass filter which does not have a series resonator for generating an attenuation pole, (b) is a graph which shows the present invention shown in FIGS. It is a graph which shows the electrical property of the laminated type band pass filter which concerns. FIG. 3 is a schematic plan view of each dielectric layer of a second embodiment of the multilayer bandpass filter that realizes the circuit configuration shown in FIG. 1. 7 is an exploded perspective view of the bandpass filter shown in FIG. FIG. 6 is a schematic plan view of each dielectric layer constituting a third embodiment of the multilayer bandpass filter that realizes the circuit configuration shown in FIG. 1. It is a disassembled perspective view of the band pass filter shown in FIG. 10 is a graph showing the resonance frequency when the dimensions of the electrodes 44 and 45 of the dielectric layer M23 in the multilayer bandpass filter shown in FIGS. 8 and 9 are changed. FIG. 6 is an electrical equivalent circuit diagram of a conventional multilayer LC filter 100. It is a disassembled perspective view of the conventional multilayer LC filter.

Explanation of symbols

R1 first resonator R2 first resonator R3 second resonator R4 second resonator C11 capacitor C12 capacitor L1 resonant element L11 resonant element L12 resonant element C21 capacitor C22 capacitor L2 resonant element L21 resonant element L22 resonant element C31 capacitor T1 ground Terminal T2 Ground terminal IN Input terminal OUT Output terminals M1 to M6 Dielectric layer 1 Ground electrode 2 One electrode 2 ′ of capacitor C11 The other electrode 3 of capacitor C11 One electrode 3 ′ of capacitor C21 The other electrode 4 of capacitor C21 One electrode 4 'of capacitor C12 The other electrode 5 of capacitor C12 One electrode 5' of capacitor C22 The other electrode 6 of capacitor C22 One electrode 6 'of capacitor C31 One electrode of capacitor C31 7 Ground electrode 8 Resonant element Part of L12 Via conductor 9 formed Via conductor 10 constituting part of the resonant element L22 Via conductor 11 constituting part of the resonant element L12 Via conductor 12 constituting part of the resonant element L22 Via conductor 13 constituting the resonant element L11 Via conductors M11 to M17 constituting the resonant element L21 Dielectric layer T21 Ground terminal T22 Ground terminal T23 Ground terminal 21 Ground electrode 22 One electrode 22 ′ of capacitor C11 The other electrode 23 of capacitor C11 One electrode 23 ′ of capacitor C21 The other electrode 24 of the capacitor C21 One electrode 24 ′ of the capacitor C12 The other electrode 25 of the capacitor C12 The one electrode 25 ′ of the capacitor C22 The other electrode 26 of the capacitor C22 The one electrode 27 of the capacitor C31 The ground electrodes 28 to 35 Vias Conductors M21 to M28 Dielectric layer T31 Ground terminal 32 Ground terminal T33 Ground terminal T34 Ground terminal 41 Ground electrode 42 One electrode 42 ′ of capacitor C11 The other electrode 43 of capacitor C11 One electrode 43 ′ of capacitor C21 The other electrode 44 of capacitor C21 The capacitors C12, C13 and L13 One electrode 44 'The other electrode 45 of the capacitors C12, C13, L13 One electrode 45' of the capacitors C22, C23, L23 The other electrode 46 of the capacitors C22, C23, L23 One electrode 47 of the capacitor C31 One of the resonant elements Electrode 48 constituting part 49 Electrode constituting part of resonant element 49 Ground electrodes 50 to 59 Via conductor

Claims (2)

In the band-pass filter in which a plurality of first resonators that resonate in a desired pass band are arranged inside the laminate, and the first resonators are electromagnetically coupled to each other.
Each first resonator consists of an inductor conductor and a conductor capacitively coupled to the ground conductor,
One of the first resonators and the input terminal are connected by a circuit including at least one capacitor;
The other of the first resonator and the output terminal are connected by a circuit including at least one capacitor;
The electrodes on the side connected to the input terminal or the output terminal in the two electrodes constituting each capacitor are each opposed to the ground conductor,
The second resonator is configured by a minute inductor component of each electrode itself and capacitive coupling between each electrode and the ground conductor,
A multilayer bandpass filter, wherein a resonance frequency of the second resonator is set higher than a resonance frequency of the first resonator. In a diplexer composed of a filter having a first passband and a filter having a second passband,
A diplexer using a laminated band-pass filter, wherein one or both of the two filters comprises the band-pass filter according to claim 1.

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