JP2001024463A - Band preventing filter and receiving module and portable radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band preventing filter in which an attenuation band can be set so as to be wide, and the control of the attenuation band can be easily attained and a receiving module. SOLUTION: A band preventing filter 10 is provided with input and output terminals Pi and Po, inter-stage coupling capacitor Cc, serial coupling capacitors C1 and C2, and indicators L11 and L12. Notch circuits Nc11 and Nc12 constituted of the serial coupling capacitors C1 and C2 and the inductors L11 and L12 are serially connected through the inter-stage coupling capacitor Cc, and an attenuation pole due to the serial resonance of the notch circuits Nc11 and Nc12 is indicated. Also, the attenuation pole due to the parallel resonance of the M coupling of the inductors L11 and L12 and the inter-stage coupling capacitor Cc is indicated with frequencies lower than the frequencies of the attenuation pole due to the serial resonance of the notch circuits Nc11 and Nc12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band rejection filter, a receiving module, and a portable radio, and more particularly, to a band rejection filter, a receiving module, and a radio frequency circuit for receiving radio waves in a cellular phone, a pager, and the like. Related to portable radios.

[0002]

2. Description of the Related Art In recent years, various filters have been used in various wireless devices in order to reduce loss.
As one of such filters, a band rejection filter having a characteristic of actively removing a high-frequency signal in a specific frequency band is known.

FIG. 11 is an equivalent circuit diagram of a conventional band rejection filter. The band rejection filter 50 includes an input / output terminal 5
1, 52, an inter-stage coupling capacitor 53, series coupling capacitors 54 and 55, and inductors 56 and 57.

The operation of the band rejection filter 50 will be described below. The series-coupled capacitors 54 and 55 and the inductors 56 and 57 are connected in series, respectively, to form one-stage notch circuits 58 and 59 having series resonance characteristics.
The notch circuits 58 and 59 are cascade-connected by an inter-stage coupling capacitor 53, and indicate an attenuation pole due to series resonance of the notch circuits 58 and 59.

[0005]

However, the conventional band rejection filter has a problem that the attenuation band becomes narrow because of the high-pass notch type.

Another problem is that the attenuation band varies due to variations in the element characteristics of the interstage coupling capacitor, the series coupling capacitor, and the inductor constituting the band rejection filter.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and provides a band rejection filter, a reception module, and a portable wireless device having a wide attenuation band and easy control of the attenuation band. With the goal.

[0008]

In order to solve the above-mentioned problems, a band rejection filter according to the present invention comprises at least one inter-stage coupling capacitor, and a series-coupled capacitor cascaded through the inter-stage coupling capacitor. A plurality of notch circuits including inductors are included, and the inductors of the plurality of notch circuits are M-coupled.

The band rejection filter of the present invention includes at least one inter-stage coupling capacitor, and a plurality of notch circuits including a series-coupled capacitor and an inductor cascaded through the inter-stage coupling capacitor. It is characterized in that inductors of a plurality of notch circuits are coupled by -M.

Further, the band rejection filter of the present invention is characterized in that the inter-stage coupling capacitor, the series coupling capacitor and the inductor are integrated into a laminate formed by laminating a plurality of dielectric layers.

Further, in the band rejection filter of the present invention, the inductor is constituted by a strip line electrode provided inside the multilayer body, and the inter-stage coupling capacitor and the series coupling capacitor are provided inside the multilayer body by the dielectric. It is characterized by comprising a plurality of capacitor electrodes provided to face each other with a body layer interposed therebetween.

A receiving module according to the present invention is a receiving module comprising the above-described band rejection filter and a low-noise amplifier, wherein the low-noise amplifier is mounted on the laminate constituting the band-rejection filter. And

Further, the receiving module according to the present invention is characterized in that the low-noise amplifier is mounted in a cavity provided in the laminate.

A portable wireless device according to the present invention includes an antenna, a receiving system including a low-noise amplifier, a band rejection filter and a mixer, and a housing that covers the receiving system. A band rejection filter is used.

Further, a portable wireless device according to the present invention includes an antenna, a receiving system including a low-noise amplifier, a band rejection filter and a mixer, and a housing covering the receiving system. The above-described receiving module is used as a rejection filter.

According to the band rejection filter of the present invention, the inductors of the plurality of notch circuits are M-coupled.
The position of the attenuation pole formed by the coupling and the inter-stage coupling capacitor can be changed.

Further, according to the band rejection filter of the present invention, since the inductors of the plurality of notch circuits are subjected to -M coupling, by changing the degree of coupling of the inductors, the parasitic inductance generated between the notch circuit and the ground is changed. Can be reduced.

According to the receiving module of the present invention, a low-noise amplifier is mounted on a laminate obtained by laminating a plurality of dielectric layers constituting a band-stop filter, and the band-stop filter and the low-noise amplifier are mounted on the laminate. For integration, each line of the band-stop filter and the low-noise amplifier can be provided inside the laminate, and as a result, the loss in each line can be reduced.

According to the portable radio of the present invention, since the band rejection filter having good pass characteristics and the receiving module having good reception characteristics are used, deterioration of the reception sensitivity of the portable radio can be prevented. it can.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an equivalent circuit diagram of a first embodiment according to the band rejection filter of the present invention. The band rejection filter 10 includes input / output terminals Pi and Po, an interstage coupling capacitor Cc, series coupling capacitors C1 and C2, and an inductor L1.
1, L12.

The series-coupled capacitors C1 and C2 and the inductors L11 and L12 are respectively connected in series to form one-stage notch circuits Nc11 and Nc12 having a series resonance characteristic. Connected in cascade.

At this time, the inductors L11 and L12 of the notch circuits Nc11 and Nc12 are M-coupled.

With the above configuration, the band rejection filter 1
0 denotes an inductor L formed at a lower frequency than the attenuation pole due to the series resonance of the notch circuits Nc11 and Nc12 and the attenuation pole due to the series resonance of the notch circuits Nc11 and Nc12.
11 shows the M-coupling of L11 and L12 and the attenuation pole due to the parallel resonance of the inter-stage coupling capacitor Cc.

FIG. 2 is an exploded perspective view of a band rejection filter having the equivalent circuit of FIG. The laminated body 11 constituting the band rejection filter 10 is, for example, 850 ° C. to 1000 ° C.
Barium oxide, aluminum oxide, which can be fired at a temperature of
It is formed by sequentially laminating and firing first to eighth dielectric layers 11a to 11h made of low-temperature fired ceramics containing silica as a main component.

External terminals T1 are provided on the upper surface of the first dielectric layer 11a and on the side surfaces of the first to eighth dielectric layers 11a to 11h.
To T4 are formed. In addition, the second and eighth dielectric layers 1
Ground electrodes Gp1 and Gp2 are formed on the upper surfaces of 1b and 11h.

Further, strip line electrodes ST11 and ST12 are formed on the upper surface of the third dielectric layer 11c. The capacitor electrodes Cp1 and Cp2 and the capacitor electrodes Cp are provided on the upper surfaces of the fourth to seventh dielectric layers 11d to 11g.
p3, Cp4, a capacitor electrode Cp5, and capacitor electrodes Cp6, Cp7 are respectively formed.

Further, the second and third dielectric layers 11b, 1b
In 1c, a via hole electrode Vh is formed so as to penetrate through each of the dielectric layers 11b and 11c.

Then, the strip line electrodes ST11,
ST12 and the ground electrode Gp1 form inductors L11 and L12 (FIG. 1) having a microstrip line structure, respectively. Further, the capacitor electrodes Cp1 and Cp3 and the capacitor electrodes Cp2 and Cp4 facing each other with the fourth dielectric layer 11d interposed therebetween connect the series-coupled capacitors C1 and Cp4.
C2 (FIG. 1).

Furthermore, the fifth and sixth dielectric layers 11e, 11e,
11f, the capacitor electrodes Cp facing each other.
3 to Cp7 constitute the interstage coupling capacitor Cc (FIG. 1). Also, the ground electrode Gp1, the strip line electrodes ST11, ST12, and the strip line electrodes ST11, ST11,
ST12 and capacitor electrodes Cp1 and Cp2 are connected to each other by via-hole electrodes Vh inside laminated body 11.

The strip line electrodes ST11, S
T12 is formed line-symmetrically on the third dielectric layer 11c. Thereby, the strip line electrodes ST11, ST1 constituting the inductors L11, L12 (FIG. 1)
2 forms an M coupling, and as a result, inductors L11 and L1
2 forms an M bond.

The external terminals T1 and T3 are input / output terminals Pi and Po (FIG. 1) of the band rejection filter 10, and the external terminal T
2 and T4 are ground terminals.

FIG. 3 is a diagram showing the pass characteristics of a band rejection filter having the equivalent circuit of FIG. 3, a solid line indicates the band rejection filter 10 (FIG. 1) of the first embodiment, and a broken line indicates the band rejection filter 50 (FIG. 11) of the conventional example.

From this figure, it can be seen that the notch circuits Nc11, Nc12 in the band rejection filter 10 (solid line) of the first embodiment.
Near the 1.95 GHz attenuation pole due to series resonance of the inductors L11 and L12 and the interstage coupling capacitor C
It is understood that an attenuation pole due to parallel resonance with c occurs near 1.85 GHz, and the attenuation band is about 200 MHz. This attenuation band is about 120 MHz wider than the attenuation band of the conventional band rejection filter 50 (broken line) of about 80 MHz.

According to the band rejection filter of the first embodiment, since the inductors of the plurality of notch circuits are M-coupled, by changing the degree of coupling of the inductors, the M-coupling of the inductors and the inter-stage coupling capacitors are reduced. The position of the attenuation pole formed by the parallel resonance can be changed. As a result, it is possible to easily widen the attenuation band by moving the attenuation pole formed by the parallel resonance of the M coupling of the inductor and the inter-stage coupling capacitor.

Further, since the interstage coupling capacitor, the series coupling capacitor, and the inductor are integrated into a laminate formed by laminating the first to eighth dielectric layers, the interstage coupling capacitor, the series coupling capacitor, and the inductor are integrated. Each wiring to be connected can be provided inside the laminate. Therefore,
Since the loss in each wiring can be reduced, a band rejection filter having good pass characteristics can be obtained.

Further, a plurality of capacitors in which the inductor is constituted by a strip line electrode provided inside the multilayer body, and the inter-stage coupling capacitor and the series coupling capacitor are provided inside the multilayer body with the dielectric layer interposed therebetween. Since it is composed of electrodes, the number of components of the band rejection filter can be reduced. Therefore, the cost and size of the band rejection filter can be reduced.

FIG. 4 is an equivalent circuit diagram of a second embodiment according to the band rejection filter of the present invention. Band stop filter 2
0 is the input / output terminals Pi, Po, the interstage coupling capacitor C
c, series-coupled capacitors C1 and C2, inductor L2
1, L22.

The series-coupled capacitors C1 and C2 and the inductors L21 and L22 are respectively connected in series to form one-stage notch circuits Nc21 and Nc22 having a series resonance characteristic. Connected in cascade.

At this time, the inductors L21 and L22 of the notch circuits Nc21 and Nc22 are coupled by -M.

With the above configuration, the band rejection filter 2
0 indicates an attenuation pole due to series resonance of the notch circuits Nc21 and Nc22.

FIG. 5 is an exploded perspective view of a band rejection filter having the equivalent circuit of FIG. The laminated body 21 constituting the band rejection filter 20 is, for example, 850 ° C. to 1000 ° C.
Barium oxide, aluminum oxide, which can be fired at a temperature of
It is formed by sequentially laminating and firing first to eighth dielectric layers 21a to 21h made of low-temperature fired ceramics containing silica as a main component.

External terminals T1 are provided on the upper surface of the first dielectric layer 21a and the side surfaces of the first to eighth dielectric layers 21a to 21h.
To T4 are formed. In addition, the second and eighth dielectric layers 2
Ground electrodes Gp1 and Gp2 are formed on the upper surfaces of 1b and 21h.

Further, strip line electrodes ST21 and ST22 are formed on the upper surface of the third dielectric layer 21c. The capacitor electrodes Cp1 and Cp2 and the capacitor electrodes Cp are provided on the upper surfaces of the fourth to seventh dielectric layers 21d to 21g.
p3, Cp4, a capacitor electrode Cp5, and capacitor electrodes Cp6, Cp7 are respectively formed.

Further, the second and third dielectric layers 21b, 2
In 1c, a via hole electrode Vh is formed so as to penetrate through each of the dielectric layers 21b and 21c.

Then, the strip line electrodes ST21, ST21,
ST22 and the ground electrode Gp1 form inductors L21 and L22 (FIG. 4) having a microstrip line structure, respectively. Further, the capacitor electrodes Cp1 and Cp3 and the capacitor electrodes Cp2 and Cp4 facing each other across the fourth dielectric layer 21d sandwich the series-coupled capacitors C1 and Cp4.
C2 (FIG. 4).

Further, the fifth and sixth dielectric layers 21e, 21e,
Capacitor electrodes Cp facing each other across 21f
3 to Cp7 constitute an interstage coupling capacitor Cc (FIG. 4). Also, the ground electrode Gp1, the strip line electrodes ST21, ST22, and the strip line electrodes ST21, ST21,
ST22 and capacitor electrodes Cp1 and Cp2 are connected to each other by via-hole electrodes Vh inside laminated body 21.

The strip line electrodes ST21, S
T22 is formed point-symmetrically on the third dielectric layer 21c. Thereby, the strip line electrodes ST21 and ST2 forming the inductors L21 and L22 (FIG. 4)
2 form an -M coupling, and as a result, inductors L21, L2
22 forms an -M bond.

The external terminals T1 and T3 are the input / output terminals Pi and Po (FIG. 4) of the band rejection filter 20, and the external terminal T
2 and T4 are ground terminals.

FIG. 6 is a diagram showing the pass characteristics of a band rejection filter having the equivalent circuit of FIG. 6, the solid line indicates the band rejection filter 20 (FIG. 4) of the second embodiment, and the broken line indicates the band rejection filter 50 (FIG. 11) of the conventional example.

From this figure, it can be seen that the notch circuits Nc21 and Nc22 in the band rejection filter 20 (solid line) of the second embodiment.
It can be understood that an attenuation pole due to series resonance occurs around 1.95 GHz, and an attenuation of about −50 dB can be obtained while maintaining an attenuation band (about 115 MHz) higher than the conventional example. This attenuation is about 20 dB larger than the attenuation of the conventional band rejection filter 50 (broken line), which is about -30 dB.

According to the band rejection filter of the second embodiment, since the inductors of the plurality of notch circuits are coupled by -M, the degree of coupling between the notch circuits and the ground is changed by changing the coupling degree of the inductors. Parasitic inductance can be reduced.

Further, since the mutual inductance generated by -M coupling is added to the self-inductance of the notch circuit, the Q value increases, and the attenuation can be easily increased.

Further, since the inter-stage coupling capacitor, the series coupling capacitor and the inductor are integrated into a laminate formed by laminating the first to eighth dielectric layers, the inter-stage coupling capacitor, the series coupling capacitor and the inductor are integrated. Each wiring to be connected can be provided inside the laminate. Therefore, the loss in each wiring can be reduced, and a band rejection filter having good pass characteristics can be obtained.

Further, a plurality of capacitors in which the inductor is constituted by a strip line electrode provided inside the multilayer body, and the inter-stage coupling capacitor and the series coupling capacitor are provided inside the multilayer body with the dielectric layer interposed therebetween. Since it is composed of electrodes, the number of components of the band rejection filter can be reduced. Therefore, the cost of the band rejection filter can be reduced,
Miniaturization is possible.

FIG. 7 is an equivalent circuit diagram of one embodiment according to the receiving module of the present invention. The receiving module 30 includes a low noise amplifier 31, a band rejection filter 32, an input terminal PI
And an output terminal PO, and a band rejection filter 32 is connected to a stage subsequent to the low noise amplifier 31.

The low noise amplifier 31 includes transistors Q1,
Q2, inductor L1, capacitors C3 to C5, resistor R
1 to R4, and the band rejection filter 32
This is the same as the band rejection filter 10 of FIG.

FIG. 8 is a perspective view of a receiving module having the equivalent circuit of FIG. The receiving module 30 has a structure in which a low-noise amplifier 31 is mounted as an IC on a laminated body 33 constituting a band rejection filter 32.

At this time, external terminals T31 to T34 are provided from the upper surface to the lower surface of the laminate 33, and the external terminals T3 to T34 are provided.
1, T33 are input / output terminals PI, P of the receiving module 30
O (FIG. 7), the external terminals T32 and T34 serve as ground terminals.

Although not shown, electrodes constituting each element of the band rejection filter as shown in FIG. 2 are formed on the plurality of dielectric layers forming the laminate 33.

FIG. 9 is a partially transparent perspective view of a modification of the receiving module of FIG. The receiving module 30a is configured as shown in FIG.
, The low-noise amplifier 31 constitutes a band rejection filter 32 as an IC.
A different point is that it is mounted in a cavity 34 provided on the surface of a.

The cavity 34 is formed by laminating a dielectric layer (not shown) having an opening at a position where the cavity 34 is formed in the upper layer when the laminate 33a is formed. After the low-noise amplifier 31 is mounted, the cavity 34 is sealed by filling with a resin 35.

According to the receiving module of the above embodiment,
A low-noise amplifier is added to the stack constituting the band-stop filter.
Since it is mounted as C, each wiring between the band rejection filter and the low noise amplifier can be provided inside the laminate. Therefore, since the loss in each wiring can be reduced, a receiving module having good receiving characteristics can be obtained.

In the modification shown in FIG. 9, since the low-noise amplifier is mounted in the cavity provided in the laminate constituting the band rejection filter, the low-noise amplifier does not jump out of the surface of the laminate. Therefore, the possibility that the low noise amplifier is peeled off from the stacked body is reduced, and the reliability of the receiving module is improved.

FIG. 10 is an RF block diagram of a portable telephone which is a general portable radio. In FIG.
Denotes an antenna, Rx and Tx denote receiving and transmitting systems connected to the antenna ANT via the switch SW, and COV denotes a housing that covers the switch SW, the receiving system Rx and the transmitting system Tx.

At this time, the receiving system Rx is a low-noise amplifier LN
A, including a band rejection filter BEF and a mixer MIX,
The transmission system Tx includes a high-power amplifier PA and a band-pass filter B
It is composed of a PF and a mixer MIX. Also, the receiving system Rx
A mixer SYN for generating a local signal is connected to one input of the mixer MIX of the transmission system Tx and the mixer MIX of the transmission system Tx.

The band rejection filters BEF of the receiving system Rx, which is the high frequency circuit of the portable telephone, are shown in FIGS. 2 and 5, the band rejection filters 10 and 20, the low noise amplifier LNA and the band rejection filter BPF are shown in FIGS. The receiving modules 30, 30a shown in FIG.

According to the portable radio of the above-described embodiment, since a small band rejection filter having good pass characteristics and a small receiving module having good reception characteristics are used, the reception sensitivity of the portable radio is reduced. Deterioration can be prevented. Therefore, the size of the portable wireless device can be reduced, and the reliability can be improved.

In the above-described embodiments of the band rejection filter and the receiving module, the case where the dielectric layer is made of ceramics containing barium oxide, aluminum oxide and silica as main components has been described. Any material may be used as long as it is as described above. For example, a similar effect can be obtained by using a ceramic mainly containing magnesium oxide or silica or a fluororesin.

In the above embodiment of the band rejection filter, the case of the equivalent circuit as shown in FIGS. 1 and 4 has been described.
At least comprising an inter-stage coupling capacitor and a notch circuit,
It is only necessary that the inductor of the notch circuit be M-coupled or -M-coupled. An equivalent is that an inductor is connected in parallel with the interstage coupling capacitor or a capacitor is connected between the input / output terminal and the interstage coupling capacitor. It may be a circuit.

Further, the case where the inter-stage coupling capacitor and the series coupling capacitor are constituted only by a plurality of capacitor electrodes provided to face each other with the dielectric layer interposed therebetween in the laminated body has been described. You may. In this case, it is possible to form an attenuation band in a low-frequency region of 500 MHz or less by increasing the capacity of the chip capacitors constituting the interstage coupling capacitor and the series coupling capacitor.

In the above-described embodiment of the receiving module, the band rejection filter having the M-coupling shown in FIG. 1 has been described. However, the same effect can be obtained even with the -M coupling shown in FIG. .

Further, the equivalent circuit of the low-noise amplifier has been described, but this equivalent circuit is an example, and the same effect can be obtained with a low-noise amplifier having another equivalent circuit.

Further, in the modified example, the case where the cavity provided in the laminated body is sealed by filling the resin is described. However, the cavity may be sealed with a cap made of metal or ceramic. In this case, the low-noise amplifier can be mounted on a bare chip or other electronic components can be mounted on the cap. As a result, the cost of the receiving module can be reduced and the size of the receiving module can be reduced. Become.

Although the case where the cavity for mounting the low-noise amplifier is provided on the upper surface of the laminate has been described, the cavity may be provided on the lower surface of the laminate. In this case,
It is possible to mount another electronic component on the upper surface of the laminate, and as a result, it is possible to further reduce the size of the receiving module.

[0075]

According to the band rejection filter of the first aspect,
Since the inductors of the plurality of notch circuits are M-coupled, the position of the attenuation pole formed by the M-coupling of the inductors and the interstage coupling capacitor can be changed by changing the degree of coupling of the inductors. As a result, the attenuation band can be easily widened by moving the attenuation pole.

According to the band rejection filter of the second aspect, since the inductors of the plurality of notch circuits are coupled by -M, the parasitic inductance generated between the notch circuit and the ground can be reduced by changing the degree of coupling of the inductors. Can be smaller.

Further, since the mutual inductance generated by -M coupling is added to the self-inductance of the notch circuit, the Q value increases, and the attenuation can be easily increased.

According to the band rejection filter of the third aspect, since the interstage coupling capacitor, the series coupling capacitor, and the inductor are integrated into a laminate formed by laminating a plurality of dielectric layers, the interstage coupling capacitor, the series Each wiring for connecting the coupling capacitor and the inductor can be provided inside the laminate. Therefore, the loss in each wiring can be reduced, and a band rejection filter having good pass characteristics can be obtained.

According to the band rejection filter of the fourth aspect, the inductor is constituted by the strip line electrode provided inside the multilayer body, and the interstage coupling capacitor and the series coupling capacitor are sandwiched by the dielectric layer inside the multilayer body. Since it is composed of a plurality of capacitor electrodes provided to face each other, the number of components of the band rejection filter can be reduced. Therefore,
The cost and size of the band rejection filter can be reduced.

According to the receiving module of the present invention, since the low noise amplifier is mounted on the laminated body constituting the band rejection filter, each wiring between the band rejection filter and the low noise amplifier is provided inside the laminated body. Can be. Therefore, since the loss in each wiring can be reduced, a receiving module having good receiving characteristics can be obtained.

According to the receiving module of the present invention, since the low-noise amplifier is mounted in the cavity provided in the laminate forming the band rejection filter, the low-noise amplifier does not jump out of the surface of the laminate. Therefore, the possibility that the low noise amplifier is peeled off from the stacked body is reduced, and the reliability of the receiving module is improved.

According to the portable wireless device of the present invention, since a small band rejection filter having good pass characteristics is used,
Deterioration of the reception sensitivity of the portable wireless device can be prevented.
Therefore, the size of the portable wireless device can be reduced,
Reliability can be improved.

According to the portable wireless device of the present invention, since a small receiving module having good receiving characteristics is used, it is possible to prevent the receiving sensitivity of the portable wireless device from deteriorating. Therefore, the size of the portable wireless device can be reduced, and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a first embodiment according to a band rejection filter of the present invention.

FIG. 2 is an exploded perspective view of one embodiment of a band rejection filter including the equivalent circuit of FIG. 1;

FIG. 3 is a diagram illustrating pass characteristics of the band rejection filter of FIG. 2;

FIG. 4 is an equivalent circuit diagram of a second embodiment according to the band rejection filter of the present invention.

FIG. 5 is an exploded perspective view of one embodiment of a band rejection filter having the equivalent circuit of FIG. 4;

FIG. 6 is a diagram illustrating a pass characteristic of the band rejection filter of FIG. 5;

FIG. 7 is an equivalent circuit diagram of an embodiment according to the receiving module of the present invention.

8 is a perspective view of one embodiment of a receiving module including the equivalent circuit of FIG. 7;

FIG. 9 is a partially transparent perspective view of a modification of the receiving module of FIG. 8;

FIG. 10 is an RF block diagram of a general mobile phone.

FIG. 11 is an equivalent circuit diagram of a conventional band rejection filter.

[Explanation of symbols]

10, 20, 32 Band stop filter 11, 21 Laminated body 11a to 11h, 21a to 21h Dielectric layer 30, 30a Receiving module 31 Low noise amplifier 34 Cavity C1, C2 Series coupling capacitor Cc Interstage coupling capacitor Cp1 to Cp7 Capacitor electrode L11, L12, L21, L22 Inductor Nc11, Nc12, Nc21, Nc22 Notch circuit ST11, ST12, ST21, ST22 Strip line electrode

Continued on the front page F term (reference) 5E082 AA01 AB03 BB01 DD08 DD13 EE04 EE23 EE35 FG06 FG26 GG10 LL15 5J024 AA01 BA01 CA09 DA01 DA29 EA05 FA00

Claims (8)

[Claims] 1. at least one inter-stage coupling capacitor;
A band rejection filter including a plurality of notch circuits each including a series-coupled capacitor and an inductor cascade-connected via the inter-stage coupling capacitor, and wherein the inductors of the plurality of notch circuits are M-coupled. 2. at least one inter-stage coupling capacitor;
A band rejection filter including a plurality of notch circuits each including a series-coupled capacitor and an inductor cascaded through the inter-stage coupling capacitor, and -M coupling inductors of the plurality of notch circuits. 3. The integrated circuit according to claim 1, wherein the inter-stage coupling capacitor, the series coupling capacitor, and the inductor are integrated into a laminate formed by laminating a plurality of dielectric layers.
Alternatively, the band rejection filter according to claim 2. 4. An inductor comprising a strip line electrode provided inside the multilayer body, wherein the interstage coupling capacitor and the series coupling capacitor face each other with the dielectric layer interposed inside the multilayer body. 4. The band elimination filter according to claim 3, wherein the band elimination filter is configured by a plurality of capacitor electrodes provided. 5. A receiving module comprising the band-stop filter according to claim 3 and a low-noise amplifier, wherein the low-noise amplifier is mounted on the laminate constituting the band-stop filter. A receiving module characterized by the above-mentioned. 6. The receiving module according to claim 5, wherein the low-noise amplifier is mounted in a cavity provided in the laminate. 7. A reception system including an antenna, a low-noise amplifier, a band rejection filter, and a mixer, and a housing that covers the reception system, wherein the band rejection filter includes: A portable wireless device using the band rejection filter according to any one of the above. 8. A low noise amplifier and a band rejection filter, comprising: a receiving system including an antenna, a low noise amplifier, a band rejection filter and a mixer, and a housing covering the reception system. A portable wireless device using the receiving module according to claim 6.