JP2002280862A - Composite lc filter circuit and composite lc filter component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite LC filter with a small insertion loss where the effect of a terminating state of input/output terminals on a pass band is small and to provide a composite LC filter component. SOLUTION: A band pass filter F11 is connected between a common input output terminal 12 and an input output terminal 13 and a band pass filter F12 is connected between the common input output terminal 12 and an input output terminal 14 in the composite LC filter circuit 11. The band pass filter F11 comprises a series resonance circuit including an inductor L1 and a capacitor C1 and has a pass band f1 whose center frequency is the series resonance frequency. The band pass filter F12 comprises a series resonance circuit including an inductor L2 and a capacitor C2 and has a pass band f2 (>f1) whose center frequency is the series resonance frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite LC filter circuit and a composite LC filter component, for example, a composite LC filter circuit used as a duplexer or a multiplexer for a mobile communication device such as a mobile phone. And a composite LC filter component.

[0002]

2. Description of the Related Art Conventionally, a composite LC filter circuit used as a duplexer is shown in FIG. In the composite LC filter circuit 10, a low-pass filter (low-pass filter) F 1 is connected between the common input / output terminal 1 and the input / output terminal 2, and between the common input / output terminal 1 and the input / output terminal 3. A high-pass filter (high-pass filter) F2 is connected. Low-pass filter F1
Has a parallel circuit composed of an inductor L1 and a capacitor C1, and a connection point on the input / output terminal 2 side of the inductor L1 and the capacitor C1 is connected to a ground terminal G1 via a capacitor C2. The high-pass filter F2 has a series circuit including capacitors C3 and C4, and an intermediate connection point between the capacitors C3 and C4 is connected to a ground terminal G via a series circuit including a capacitor C5 and an inductor L2.
2 are connected.

[0003]

However, the conventional composite LC filter circuit 10 has a low-pass filter F1.
And the high-pass filter F2, it has a capacitor C2 and an inductor L2 connected to the ground terminals G1 and G2. Therefore, the input / output terminals 2,
There is a problem that the filter characteristics of the composite LC filter circuit 10 change greatly depending on the termination state of No. 3. Further, when a duplexer having a similar splitting frequency is configured, there is a problem that insertion loss increases.

An object of the present invention is to provide a composite LC filter circuit and a composite LC filter which have a small influence on the pass band due to the termination state of the input / output terminals and have a small insertion loss.
It is to provide a filter component.

[0005]

In order to achieve the above object, a composite LC filter circuit according to the present invention is a composite LC filter circuit for splitting or combining at least two signals of different frequencies. A first band-pass filter constituted by a first series LC resonance circuit;
At least a second band-pass filter constituted by a series LC resonance circuit of the first and second band-pass filters, wherein the pass band f1 of the first band-pass filter and the pass band f2 of the second band-pass filter are different, and One of the input / output terminals of the first band-pass filter and one of the input / output terminals of the second band-pass filter are common input / output terminals.

[0006] With the above configuration, there is no inductor or capacitor grounded to the ground, and there is no fear that the pass band characteristics of the composite LC filter circuit greatly change depending on the termination state of the input / output terminals.

Further, the composite LC filter circuit according to the present invention constitutes a parallel LC resonance circuit including at least one of an inductor and a capacitor of the first series LC resonance circuit, The frequency is set to be within the range of the pass band f2 of the second band pass filter. Alternatively, a parallel LC resonance circuit is configured to include at least one of the inductor and the capacitor of the second series LC resonance circuit, and the resonance frequency of the parallel resonance circuit is set within the range of the pass band f1 of the first band pass filter. It is set to be inside.

With the above configuration, the parallel LC resonance circuit has
Since the pole is designed to be located within the pass band of the band pass filter on the partner side, the parallel L
The impedance of the C resonance circuit is infinite. Therefore, signal leakage to the other party is reduced, and the pass band f
Even when 1 and f2 are close to each other, the insertion loss of each bandpass filter can be reduced.

Further, a composite LC filter component according to the present invention includes a composite LC filter circuit having the above-described features.
A plurality of insulator layers are provided in a stacked structure. With the above configuration, a compact and low-profile composite LC filter component can be obtained. Further, a common input / output terminal of the first and second bandpass filters is provided on the surface of the laminate, and the other input / output terminal of each of the first and second bandpass filters is provided, and a ground terminal is provided. By avoiding this, the stray capacitance can be suppressed, and the loss can be further reduced. Further, since the variation of the stray capacitance is small, the frequency characteristics are stabilized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a composite LC filter circuit and a composite LC filter component according to the present invention will be described with reference to the accompanying drawings.

[First Embodiment, FIGS. 1 to 6] FIG. 1 shows an embodiment of a composite LC filter circuit according to the present invention. The composite LC filter circuit 11 has a common input / output terminal 1
A band-pass filter (band-pass filter) F11 is connected between the input / output terminal
A bandpass filter (bandpass filter) F12 is connected between the input and output terminal 14. The band-pass filter F11 is configured by a series resonance circuit of the inductor L1 and the capacitor C1, and has a pass band f1 whose center frequency is the series resonance frequency. Bandpass filter F
Reference numeral 12 denotes a series resonance circuit including an inductor L2 and a capacitor C2, and has a pass band f2 (> f1) whose center frequency is the series resonance frequency.

With the above configuration, a high frequency signal in a low frequency range can pass between the terminals 12 and 13 and a high frequency signal in a high frequency range can pass between the terminals 12 and 14. For example, an antenna is connected to the common input / output terminal 12, a transmitting circuit is connected to the input / output terminal 13, and a receiving circuit is connected to the input / output terminal 14, respectively.
When the 950 MHz transmission signal is used for digital cellular 800), the 950 MHz transmission signal output from the transmission circuit passes through the band-pass filter F12 and is transmitted from the antenna. On the other hand, 820MHz received by the antenna
Is passed through the band-pass filter F11 and output to the receiving circuit.

As another example, a common input / output terminal 12
, An input / output terminal 14 is connected to a transmission / reception circuit corresponding to 1.9 GHz, and an input / output terminal 13 is connected to a transmission / reception circuit corresponding to 800 MHz. 9 GHz PCS (P
personal Communication Ser
device) and an 800 MHz AMPS (A
advanced Mobile Phone Serve
In the case of demultiplexing or multiplexing with the high frequency signal of (ice), the 1.9 GHz reception signal received by the antenna is output to the 1.9 GHz reception circuit through the band-pass filter F12, and is received by the antenna. The received 800 MHz signal passes through the band-pass filter F11 and
It is output to the receiving circuit of MHz. Conversely, the transmission signal output from the 1.9 GHz transmission circuit is transmitted from the antenna through the band-pass filter F12,
Is transmitted from the antenna after passing through the band-pass filter F11. In this case, it can be used as a high frequency splitter or a high frequency multiplexer for dual band. Therefore, the size of the dual band mobile communication device can be reduced.

The composite type LC filter circuit 11
In this configuration, there is no inductor or capacitor grounded to the ground, and it is possible to suppress a change in the pass band due to the termination of the input / output terminals 13 and 14. The solid line 21A in FIG.
FIG. 4 shows a transmission characteristic between the terminal 12 and the terminal 13 when a terminal resistance R of 50Ω is connected to the terminal 14 as shown in FIG. Dotted line 21B indicates the pass characteristic between terminal 12 and terminal 13 when terminal 14 is open (R = ∞). At this time, no high-frequency signal flows through the terminal 14. Dotted line 21
C indicates a pass characteristic between the terminal 12 and the terminal 13 when the terminal 14 is short-circuited (R = 0). At this time, the high-frequency signal flowing through the terminal 14 flows to the ground, and an attenuation pole is formed at the position of the resonance frequency of the series resonance circuit including the inductor L2 and the capacitor C2.

On the other hand, a solid line 22A shows the passing characteristic between the terminal 12 and the terminal 14 when the terminal 13 is connected to the terminal resistor R of 50Ω. Dotted line 22B indicates the pass characteristic between terminal 12 and terminal 14 when terminal 13 is opened. At this time, no high-frequency signal flows through the terminal 13. The dotted line 22C indicates the terminal 12 when the terminal 13 is short-circuited.
3 shows the pass characteristics between the terminal 14 and the terminal 14. At this time, the terminal 13
The high frequency signal flowing through the inductor L1
An attenuation pole is formed at the position of the resonance frequency of the series resonance circuit consisting of the capacitor C1 and the capacitor C1.

As can be seen from the graph of FIG. 2, the pass band of the LC filter circuit 11 is hardly affected regardless of the termination state of the unmeasured terminal. Note that FIG. 2 shows only the open / short state, which is a typical termination state of the unmeasured side terminal. However, even if the impedance, reactance, or capacitance is changed, the influence on the pass band is small.

FIG. 3 is an exploded perspective view of the composite LC filter component 11A having the circuit configuration of FIG. As shown in FIG. 3, in the composite LC filter component 11A, bandpass filters F11 and F12 are arranged on the right and left sides of the insulator sheet 31. The insulator sheet 31 is formed by kneading ceramic dielectric powder or magnetic powder together with a binder or the like to form a sheet. The sheet thickness of each insulator sheet 31 is set to a predetermined dimension.

The capacitor patterns 32, 33 provided on the surface of the insulating sheet 31, respectively, face the capacitor patterns 34, 35 with the insulating sheet 31 interposed therebetween, forming capacitors C1, C2. Capacitor pattern 3
The reference numerals 2 and 33 are electrically connected to the inductors L1 and L2 formed of spiral coil conductor patterns via the via holes 38, respectively. These capacitor patterns and coil conductor patterns are formed by a method such as a sputtering method, a vapor deposition method, and a printing method, and are composed of Ag-Pd, Ag, Pd,
It is made of a material such as Cu.

Each sheet 31 is stacked and fired integrally to form a laminate 40 as shown in FIG. A common input / output terminal 12 is provided on the rear side surface of the laminate 40.
Are formed, and input / output terminals 1
3 and 14 are formed. The terminals 12 to 14 are formed by a method such as a sputtering method, an evaporation method, and a coating method,
It is made of a material such as Ag-Pd, Ag, Pd, Cu, and Cu alloy.

The common input / output terminal 12 is connected to inductors L1,
The input / output terminals 13 and 14 are electrically connected to the coil conductor pattern of L2,
Is electrically connected to Thus, by forming the circuit of FIG. 1 on the laminate 40, a low-profile and small-sized LC filter component 11A can be obtained. Further, since no ground terminal is provided on the surface of the laminate 40,
The stray capacitance can be suppressed, and the loss can be further reduced. Further, since there is no variation in stray capacitance, stable frequency characteristics can be obtained.

FIG. 5 is an exploded perspective view of another composite LC filter component 11B having the circuit configuration of FIG.
As shown in FIG. 5, the composite LC filter component 11B
The band-pass filters F11 and F12 are arranged above and below a laminate formed by stacking the insulator sheets 31.

The capacitor pattern 42 provided on the surface of the insulator sheet 31 faces the capacitor pattern 43 with the insulator sheet 31 interposed therebetween, forming a capacitor C1. The capacitor pattern 45 provided on the surface of the insulator sheet 31 faces the capacitor pattern 46 to form a capacitor C2. The inductor L2 is formed of a meandering coil conductor pattern provided on the surface of the insulator sheet 31.

Each sheet 31 is stacked and integrally fired to form a laminate 50 as shown in FIG. A common input / output terminal 12 is provided on the back side of the laminate 50.
Are formed, and a relay terminal 16 is formed on the side surface on the near side. The input / output terminals 14,
13 are formed.

The common input / output terminal 12 is connected to the lead pattern 4
1 and one end of the coil conductor pattern of the inductor L2. The input / output terminals 13 and 14 are electrically connected to capacitor patterns 43 and 46, respectively. The relay terminal 16 is electrically connected to the other end of the coil conductor pattern of the inductor L2 and the capacitor pattern 45. Further, a chip inductor L1 that electrically connects the lead pattern 41 and the capacitor pattern 42 is mounted on the upper surface of the multilayer body 50. Thus, by forming the circuit of FIG. 1 on the laminate 50,
A low-profile and small LC filter component 11B can be obtained.

[Second Embodiment, FIGS. 7 and 8] As shown in FIG. 7, the composite LC filter circuit 51 of the second embodiment
Is the same as the LC filter circuit 11 shown in FIG. 1 except that the capacitor C3 is connected in parallel with the inductor L1 and the inductor L3 is connected in parallel with the capacitor C2.

The parallel resonance frequency of the parallel resonance circuit including the inductor L1 and the capacitor C3 of the band-pass filter F11 is changed to the pass band f2 of the band-pass filter F12.
Designed to go inside. That is, the band-pass filter F11 is connected to the pass band f2 of the band-pass filter F12.
, And the impedance of the filter F11 is infinite within the band f2. The capacitor C of the band-pass filter F12
It is designed such that the parallel resonance frequency of the parallel resonance circuit including the inductor 2 and the inductor L3 falls within the pass band f1 of the low-pass filter F11. That is, the band-pass filter F
Numeral 12 is designed so that the pole is located within the pass band f1 of the band-pass filter F11, and the impedance of the filter F12 is infinite within the band f1. As a result, the leakage of the high-frequency signal to the partner band-pass filter is reduced, and the insertion loss of each of the filters F11 and F12 can be reduced even when the pass bands f1 and f2 are close to each other.

With the above configuration, the input / output terminals 13 and 14
, A composite LC filter circuit 51 having a small change in the pass band due to the termination state can be obtained. Solid line 52A in FIG.
Is obtained by connecting a terminal resistance R of 50Ω to the terminal 14.
3 shows a transmission characteristic between the terminal 12 and the terminal 13. Dotted line 52B
Is the terminal 1 when the terminal 14 is opened (R = ∞).
3 shows a pass characteristic between the terminal 2 and the terminal 13. Dotted line 52C indicates the pass characteristics between terminal 12 and terminal 13 when terminal 14 is short-circuited (R = 0).

On the other hand, the solid line 53A shows the passing characteristic between the terminal 12 and the terminal 14 when the terminal 13 is connected to the terminal resistance R of 50Ω. Dotted line 53B indicates the passing characteristic between terminal 12 and terminal 14 when terminal 13 is opened. Dotted line 53C shows the passing characteristic between terminal 12 and terminal 14 when terminal 13 is short-circuited.

As can be seen from the graph of FIG. 8, the pass band of the LC filter circuit 51 is hardly affected irrespective of the termination state of the unmeasured terminal. Note that FIG. 8 shows only the open / short state, which is a typical termination state of the non-measurement side terminal. However, even if the impedance, reactance, or capacitance is changed, the influence on the pass band is small.

[Third Embodiment, FIGS. 9 and 10] A third embodiment is a composite type LC for splitting signals of three different frequencies or multiplexing signals of three different frequencies. The filter circuit will be described.

As shown in FIG. 9, the composite LC filter circuit 61 is composed of three band-pass filters F11 to F13. The band pass filter F11 is connected between the common input / output terminal 12 and the input / output terminal 13, and the pass band is set to f1. Bandpass filter F1
2 is connected between the common input / output terminal 12 and the input / output terminal 14, and its pass band is set to f2. The bandpass filter F13 is connected between the common input / output terminal 12 and the input / output terminal 15, and its passband is set to f3. The bands f1 to f3 have a relationship of f1 <f2 <f3.

The band-pass filter F11 includes an inductor L
1 and L4 and capacitors C1 and C4. Then, the resonance frequency of the parallel resonance circuit including the inductor L1 and the capacitor C4 is changed by the band-pass filter F.
12 and within a pass band f2.
The resonance frequency of the parallel resonance circuit including the capacitor C1 and the inductor L4 is changed to the pass band f of the band-pass filter F13.
3 is designed. Therefore, the band-pass filter F11 has attenuation poles in the bands f2 and f3, respectively, and the impedance of the filter F11 is infinite in the bands f2 and f3 (see the solid line 62 in FIG. 10).

The band-pass filter F12 includes an inductor L
2 and L5 and capacitors C2 and C5. Then, the resonance frequency of the parallel resonance circuit including the inductor L2 and the capacitor C5 is changed by the bandpass filter F.
11 and within the passband f1.
The resonance frequency of the parallel resonance circuit including the capacitor C2 and the inductor L5 is changed to the pass band f of the band-pass filter F13.
3 is designed. Therefore, the band-pass filter F12 has attenuation poles in the bands f1 and f3, respectively, and the impedance of the filter F12 is infinite in the bands f1 and f3 (see the solid line 63 in FIG. 10).

The band-pass filter F13 includes an inductor L
3 and L6 and capacitors C3 and C6. Then, the resonance frequency of the parallel resonance circuit including the inductor L3 and the capacitor C6 is changed by the band-pass filter F.
11 and within the passband f1.
The resonance frequency of the parallel resonance circuit including the capacitor C3 and the inductor L6 is changed to the pass band f of the bandpass filter F12.
It is designed to be within 2. Therefore, the band-pass filter F13 has attenuation poles in the bands f1 and f2, respectively, and the impedance of the filter F13 is infinite in the bands f1 and f2 (see the solid line 64 in FIG. 10).

That is, the pass band f1 of the band pass filter F11 is a frequency region where the impedance of the band pass filters F12 and F13 becomes infinite. The pass band f2 of the band pass filter F12 is different from the band pass filter F1.
1, a frequency region where the impedance of F13 becomes infinite. The pass band f3 of the band pass filter F13 is a frequency region where the impedance of the band pass filters F11 and F12 is infinite. As a result, signal leakage is small, and the insertion loss of each filter can be reduced.

In the composite type LC filter circuit 61 having the above configuration, the high frequency signal in the band f1 passes between the common input / output terminal 12 and the input / output terminal 13, and the high frequency signal in the band f2 is And the high-frequency signal of the band f3 passes between the common input / output terminal 12
And the input / output terminal 15.

For example, an 800 MHz AMPS (Adv
anced Mobile Phone Service
e), a 1.5 GHz GPS high frequency signal, and a 1.8 to 1.9 GHz PCS (Persona).
l When demultiplexing or multiplexing a high frequency signal of Communication Service), an antenna is connected to the common input / output terminal 12 and 8
A transmitting / receiving circuit corresponding to 00 MHz is connected, a transmitting / receiving circuit corresponding to 1.5 GHz is connected to the input / output terminal 14, and a transmitting / receiving circuit corresponding to 1.8 to 1.9 GHz is connected to the input / output terminal 15. Connect.

Thus, the 800M received by the antenna
The received signal of Hz passes through the band-pass filter F11 and is output to the receiving circuit of 800 MHz. The 1.5 GHz reception signal received by the antenna is transmitted to the bandpass filter F1.
2 and output to a 1.5 GHz receiving circuit. The received signal of 1.8 to 1.9 GHz received by the antenna is
1.8 to 1.9 GH after passing through the band-pass filter F13
z is output to the receiving circuit. Conversely, the transmission signal output from the 800 MHz transmission circuit is transmitted to the bandpass filter F1.
1 and transmitted from the antenna. The transmission signal output from the 1.5 GHz transmission circuit passes through the band-pass filter F12 and is transmitted from the antenna. 1.8-
The transmission signal output from the 1.9 GHz transmission circuit passes through the band-pass filter F13 and is transmitted from the antenna.

The combination of high-frequency signals to be split or multiplexed is a PDC 800 (Personal Di).
digital cellular 800), a PDC 1500 high frequency signal, and a W-CDMA high frequency signal. Alternatively, a combination of a GSM high-frequency signal, a DCS high-frequency signal, and a W-CDMA high-frequency signal may be used.

[Other Embodiments] It should be noted that the composite LC filter circuit and the composite LC filter component according to the present invention are not limited to the above-described embodiments, but can be variously modified within the scope of the invention. . For example, the embodiment may separate two or three different frequency signals,
Alternatively, two or three signals of different frequencies are multiplexed, but the present invention is not limited to this, and the present invention may be applied to a device of demultiplexing or multiplexing signals of four or more different frequencies. May be applied.

The LC filter circuit 11 shown in FIG.
Although the inductors L1 and L2 are arranged on the common input / output terminal 12 side, the present invention is not limited to this. The capacitors C1 and C2 may be arranged on the common input / output terminal 12 side. Alternatively, only one of the inductors L1 and L2 may be arranged on the common input / output terminal 12 side.

Further, in addition to the LC filter circuit 51 shown in FIG. 7, the circuits having the circuit configurations shown in FIGS. 11 to 19 can also provide the same functions and effects as those of the second embodiment. At this time, the band-pass filter F11 connected between the terminal 12 and the terminal 13 and the band-pass filter F12 connected between the terminal 12 and the terminal 14 do not need to have the same circuit configuration. is there. Further, the band-pass filter F shown in FIGS. 7, 9, and 11 to 19 is used.
Each of 11, 11, and 13 has a parallel resonance circuit, but at least one of the band-pass filters F11 to F13 may have a parallel resonance circuit.

In the above embodiment, the insulator sheets on which the conductors are formed are stacked and then integrally fired, but the invention is not necessarily limited to this. The sheet which has been baked in advance may be used. Further, a composite LC filter component may be manufactured by a manufacturing method described below.
A paste-like insulator material is applied by printing or the like, and a paste-like conductor material is applied to the surface of the insulator layer to form an arbitrary conductor. Next, a paste-like insulator material is applied over the conductor. In this way, a composite LC filter component having a laminated structure is obtained by successively coating.

Further, a part of the capacitor or the inductor may be mounted on the surface of the laminated body instead of a chip component, or may be externally attached.

[0045]

As is apparent from the above description, according to the present invention, the composite band L is composed of the first band-pass filter and the second band-pass filter each composed of a series LC resonance circuit.
Since the C filter circuit is configured, there is no inductor or capacitor grounded to the ground, and a composite LC filter circuit with a small change in the pass band characteristic due to the termination state of the input / output terminal can be obtained. Furthermore, by providing a parallel resonance circuit in at least one of the first band-pass filter and the second band-pass filter, it is possible to form a pole in the pass band of the other band-pass filter. it can. As a result, signal leakage to the other party is reduced, and the insertion loss of each bandpass filter can be reduced even when the passbands of the first and second bandpass filters are close.

Further, by providing the composite type LC filter circuit having the above-described features on an insulator formed by stacking a plurality of insulator layers, a compact and low-profile composite type LC filter component can be obtained. . Further, a common input / output terminal of the first and second bandpass filters is provided on the surface of the laminate, and the other input / output terminal of each of the first and second bandpass filters is provided, and a ground terminal is provided. By avoiding this, the stray capacitance can be suppressed, and the loss can be further reduced. Further, since the variation in the stray capacitance is small, stable frequency characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of a composite LC filter circuit according to the present invention.

FIG. 2 is a graph showing pass band characteristics of the composite LC filter circuit shown in FIG.

FIG. 3 is an exploded perspective view of a composite LC filter component having the circuit configuration of FIG. 1;

4 is an external perspective view of the composite LC filter component shown in FIG.

FIG. 5 is an exploded perspective view of another composite LC filter component having the circuit configuration of FIG. 1;

6 is an external perspective view of the composite LC filter component shown in FIG.

FIG. 7 is an electric circuit diagram showing a second embodiment of the composite LC filter circuit according to the present invention.

8 is a graph showing pass band characteristics of the composite LC filter circuit shown in FIG.

FIG. 9 is an electric circuit diagram showing a third embodiment of the composite LC filter circuit according to the present invention.

FIG. 10 is a graph showing passband characteristics of the composite LC filter circuit shown in FIG. 9;

FIG. 11 is an electric circuit diagram showing another embodiment of the composite LC filter circuit according to the present invention.

FIG. 12 is an electric circuit diagram showing another embodiment of the composite LC filter circuit according to the present invention.

FIG. 13 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 14 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 15 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 16 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 17 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 18 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 19 is an electric circuit diagram showing still another embodiment of the composite LC filter circuit according to the present invention.

FIG. 20 is an electric circuit diagram showing a conventional composite LC filter circuit.

[Explanation of symbols]

 11, 51, 61 composite LC filter circuit 11A, 11B composite LC filter component 12 common input / output terminal 13, 14, 15 input / output terminal 31 insulator sheet 40, 50 laminated body C1-C4 Capacitors L1 to L4 ... inductors F11, F12, F13 ... band-pass filters f1, f2, f3 ... passbands

Claims (9)

[Claims] 1. A composite LC filter circuit for splitting or combining signals of at least two different frequencies, comprising: a first band-pass filter constituted by a first series LC resonance circuit; At least a second band-pass filter configured by an LC resonance circuit, wherein a pass band f1 of the first band-pass filter and a pass band f2 of the second band-pass filter are different, and A composite LC filter circuit, wherein one input / output terminal of the first bandpass filter and one input / output terminal of the second bandpass filter are common input / output terminals. 2. A parallel LC resonance circuit including at least one of an inductor and a capacitor of the first series LC resonance circuit, wherein a resonance frequency of the parallel resonance circuit is set to a value corresponding to that of the second band pass filter. 2. The composite LC filter circuit according to claim 1, wherein the frequency is set within a range of a pass band f2. 3. A parallel LC resonance circuit including at least one of an inductor and a capacitor of the second series LC resonance circuit, wherein a resonance frequency of the parallel resonance circuit is set to a value corresponding to that of the first band-pass filter. 3. The composite LC filter circuit according to claim 1, wherein the LC band is within a range of a pass band f1. 4. The composite LC filter circuit according to claim 1, wherein an inductor and a capacitor of each LC resonance circuit are not grounded. 5. A composite LC filter, wherein the composite LC filter circuit according to claim 1 is provided in a laminate formed by stacking a plurality of insulator layers.
Filter parts. 6. The first input / output terminal of the first band-pass filter and the common input / output terminal of the first and second band-pass filters are provided on the surface of the laminate. The composite LC filter component according to claim 5, wherein the other second input / output terminal of the second band-pass filter is provided, and the ground terminal is not provided. 7. An insulator layer on which a first capacitor pattern and a second capacitor pattern are formed, a third capacitor pattern facing the first capacitor pattern, and a third capacitor pattern facing the second capacitor pattern. And an insulator layer on which the first and second inductor patterns each having one end connected to the third and fourth capacitor patterns are stacked. A first series LC resonance circuit comprising a capacitor formed of the first and third capacitor patterns and an inductor formed of the first inductor pattern. The second series LC resonance with the capacitor formed by the second inductor pattern and the inductor formed by the second inductor pattern. Forming a circuit, the common input / output terminal to which the other end of each of the first and second inductor patterns is connected is provided on the surface of the laminate, and the common input / output terminal is connected to the first capacitor pattern. 7. The composite type LC filter component according to claim 6, wherein a first input / output terminal is provided, and said second input / output terminal connected to said second capacitor pattern is provided. 8. An insulator layer on which a second capacitor pattern is formed, an insulator layer on which a fourth capacitor pattern facing the second capacitor pattern is formed, and a second inductor pattern are formed. An insulator layer on which a first capacitor pattern is formed; and a third capacitor pattern facing the first capacitor pattern, which is connected to one end of the third capacitor pattern. A stacked body formed by stacking an insulator layer on which a first inductor to be formed is formed. A series LC resonance circuit, and a capacitor comprising the second and fourth capacitor patterns and the second inductor. The second series LC resonance circuit is constituted by an inductor formed of a capacitor pattern, and is connected to one end of the second inductor pattern on the surface of the multilayer body and is connected to one end of the first inductor. The common input / output terminal is provided, the second input / output terminal connected to the second capacitor pattern is provided, and the first input / output terminal connected to the first capacitor pattern is provided. 7. The composite LC filter component according to claim 6, wherein a relay terminal is provided and connected to the fourth capacitor pattern and the second inductor pattern. 9. The composite LC filter component according to claim 8, wherein said first inductor comprises a chip inductor.