JP2000332638A - Band rejection filter, receiving module and portable radio - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band rejection filter, a receiving module and a portable radio capable of reducing the number of parts, manufacturing costs and respective sizes. SOLUTION: The band rejection filter 10 is provided with a multilayer substrate 11 consisting of 1st to 8th dielectric layers 111 to 118. Ground electrodes Gp11, Gp12 are formed on the upper surfaces of the 2nd and 8th dielectric layers 112, 118. Strip line electrodes ST11, ST12 are formed on the upper surface of the 3rd dielectric layer 113. Capacitor electrodes Cp11 to Cp17 are formed on the upper surfaces of the 4th to 7th dielectric layers 114 to 117. In addition, a via hole Vh1 is formed on the 2nd and 3rd dielectric layers 112, 113 so as to pass through the layers 112, 113.

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 types of filters have been used in various portable 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. 12 is an exploded perspective view of a conventional band rejection filter. The band rejection filter 50 has an input / output terminal 5
1, 52, dielectric coaxial resonators 53, 54, capacitor 5
5 to 57, a shield cover 58, and a mounting board 59. The capacitors 55 and 56 are connected in series to the dielectric coaxial resonators 53 and 54, and the capacitor 57 is connected between the input / output terminals 51 and 52. The mounting board 59 on which these are mounted is covered with a shield cover 58 to prevent electromagnetic interference with external circuits. The shield cover 58 has a top surface and side surfaces in three directions, and the dielectric coaxial resonators 53, 5
4 covers the entire area excluding the short-circuit end portion. The lower edge of each side surface of the shield cover 58 is fixed to the ground pattern 60 of the mounting board 59 by soldering, and the dielectric coaxial resonators 53 and 5 are fixed.
4 is fixed by soldering the top surface and the side surface. Thus, the outer conductors (not shown) of the dielectric coaxial resonators 53 and 54 become grounds. The shield cover 58 is provided with a rectangular adjustment window 61 through which an adjustment rod is inserted to adjust the resonance frequencies of the dielectric coaxial resonators 53 and 54.

[0004]

However, in the above-described conventional band rejection filter, for example, two dielectric resonators and three capacitors are required to form a two-stage filter. However, there is a problem that the number of parts is increased, so that the cost is high and the shape is large.

Further, since the shield cover covers almost the entirety, the height of the component is the sum of the thickness of the mounting board, the thickness of the dielectric resonator, the thickness of the shield cover, and the thickness of the solder for fixing. There is also a problem that the height of the rejection filter is increased.

The present invention has been made in order to solve such problems, and provides a band rejection filter, a receiving module, and a portable wireless device which have a small number of components, can be reduced in cost and can be reduced in size. The purpose is to do.

[0007]

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 an inductor and a series coupling capacitor connected in cascade via the inter-stage coupling capacitor. A plurality of notch circuits composed of a plurality of dielectric layers are integrated on a multilayer substrate.

Further, the inductor of the notch circuit is constituted by a strip line electrode provided inside the multilayer substrate, and the series coupling capacitor and the inter-stage coupling capacitor of the notch circuit are disposed inside the multilayer substrate by the dielectric material. It is characterized by comprising a plurality of capacitor electrodes provided to face each other with a layer interposed therebetween.

The receiving module of the present invention has at least one
A plurality of band-stop filters each including one inter-stage coupling capacitor, a plurality of notch circuits including an inductor and a series-coupling capacitor connected in cascade via the inter-stage coupling capacitor, and a plurality of low-noise amplifiers connected to the band-stop filter. Characterized in that it is integrated with a multilayer substrate formed by laminating the above dielectric layers.

The low-noise amplifier is mounted on the multilayer substrate, and the inductor of the notch circuit of the band rejection filter is constituted by a strip line electrode provided inside the multilayer substrate. Wherein the series coupling capacitor and the interstage coupling capacitor of the band rejection filter are constituted by a plurality of capacitor electrodes provided inside the multilayer substrate with the dielectric layer interposed therebetween.

Further, the low noise amplifier is mounted in a cavity provided in the multilayer substrate.

A portable wireless device according to the present invention uses the above-described band rejection filter.

Further, the present invention is characterized in that the above-mentioned receiving module is used.

According to the band elimination filter of the present invention, since the inter-stage coupling capacitor and the notch circuit are integrated into a multilayer substrate formed by laminating a plurality of dielectric layers, each wiring of the inter-stage coupling capacitor and the notch circuit is connected. It can be provided inside the laminate, and as a result, loss in each wiring can be reduced.

According to the receiving module of the present invention, the band rejection filter including the inter-stage coupling capacitor and the notch circuit, and the low-noise amplifier are integrated on the multilayer substrate formed by laminating a plurality of dielectric layers. Each wiring of the inter-coupling capacitor, the notch circuit, and the low-noise amplifier can be provided inside the laminate, and as a result, the loss in each wiring 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 transmission characteristics are used, deterioration of the transmission characteristics of the portable radio can be prevented. it can.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an equivalent circuit diagram of a general band rejection filter. In FIG. 1, reference numerals 1 and 2 denote input / output terminals, 3 and 4 denote inductors, 5 and 6 denote series coupling capacitors, and 7 denotes an interstage coupling capacitor.

Hereinafter, the operation of the band rejection filter will be described. The inductors 3 and 4 and the series coupling capacitors 5 and 6 are connected in series, respectively, to form one-stage notch circuits 8 and 9 having series resonance characteristics. Notch circuit 8,
Reference numeral 9 is cascade-connected by an inter-stage coupling capacitor 7, and shows a large attenuation in the transfer characteristic at the series resonance frequency of the notch circuits 8, 9. At the parallel resonance frequency of the notch circuits 8 and 9, the impedance of the notch circuits 8 and 9 becomes infinite, so that the notch circuits 8 and 9 are cascaded by the interstage coupling capacitor 7 and exhibit bandpass characteristics.

FIGS. 2 and 3 are an exploded perspective view and a sectional view of an embodiment of the band rejection filter of the present invention. The band rejection filter 10 includes first to eighth dielectric layers 111 to 1.
18 is provided.

Ground electrodes Gp11 and Gp12 are formed on the upper surfaces of the second and eighth dielectric layers 112 and 118, respectively. Further, strip line electrodes ST11 and ST12 are formed on the upper surface of the third dielectric layer 113.

Further, capacitor electrodes Cp11 and Cp12 are formed on the upper surface of the fourth dielectric layer 114. The upper surface of the fifth dielectric layer 115 has a capacitor electrode C
p13 and Cp14 are formed.

Further, a capacitor electrode Cp15 is formed on the upper surface of the sixth dielectric layer 116. Further, on the upper surface of the seventh dielectric layer 117, the capacitor electrodes Cp16, Cp16
17 are formed. Further, the second and third dielectric layers 1
Via hole electrodes Vh1 are formed in the dielectric layers 12 and 113 so as to penetrate the dielectric layers 112 and 113, respectively.

The first to eighth dielectric layers 111 to 11
Reference numeral 8 denotes, for example, a sheet obtained by kneading a dielectric ceramic mainly composed of barium oxide, aluminum oxide and silica, which can be fired at a temperature of 850 ° C. to 1000 ° C., together with a binder and the like.

Further, the strip line electrodes ST11, S
T12, capacitor electrodes Cp11 to Cp17 and ground electrodes Gp11 and Gp12 are made of Ag, Pd, Ag-P
d, Cu, etc., and the second to eighth dielectric layers 112 to 1
18 is formed on the surface by a known method such as a printing method, a sputtering method, and a vacuum evaporation method.

These first to eighth dielectric layers 111 to 1 1
18 are stacked and sintered integrally,
The multilayer substrate 11 is obtained. The ground electrode Gp11 and the strip line electrodes ST11 and ST12, and the strip line electrodes ST11 and ST12 and the capacitor electrode C
Each of p11 and Cp12 is connected via a via-hole electrode Vh1 inside the multilayer substrate 11.

On the side and front and back surfaces of the multilayer substrate 11, the external terminals T11 which are electrically connected to the capacitor electrodes Cp13 and Cp16 and serve as the input terminal 1 (FIG. 1), and the capacitor electrodes Cp14 and Cp17 are electrically connected. Connected to
The external terminal T12 serving as the output terminal 2 (FIG. 1) and the ground electrodes Gp11 and Gp12 are electrically connected to form external terminals T13 and T14 serving as ground terminals. In addition, these terminals T11 to T14 are formed by a method such as a sputtering method, a vacuum evaporation method, and coating and baking.

The band rejection filter 10 having the above configuration
, The inductors 3 and 4 (FIG. 1) are formed by the strip line electrodes ST11 and ST12. Further, the capacitor electrodes C opposed to each other with the fourth dielectric layer 114 interposed therebetween.
p11, Cp13, capacitor electrodes Cp12, Cp14
Form the series-coupled capacitors 5 and 6 (FIG. 1).

Further, the fifth and sixth dielectric layers 115,
Capacitor electrode Cp1 facing each other across
3, Cp15, Cp16, and capacitor electrode Cp1
4, Cp15 and Cp17 form the interstage coupling capacitor 7 (FIG. 1). The external terminal T11 is the input terminal 1
(FIG. 1), and the external terminal T12 is the output terminal 2 (FIG. 1).
Becomes

FIG. 4 is a diagram showing the pass characteristics of the band rejection filter of FIG. From this figure, an attenuation pole occurs around 1.8 GHz, and the bandwidth showing -20 (dB) or less is about 3
00 (MHz).

FIG. 5 is a sectional view of a modification of the band rejection filter of FIG. The band rejection filter 10a differs from the band rejection filter 10 of the embodiment of FIG. 2 in that the inductors 3 and 4 (FIG. 1) are configured by chip inductors L1 and L2 and mounted on the surface of the multilayer substrate 11a. . Note that the chip inductors L1 and L2 and the capacitor electrodes Cp11 and Cp12 inside the multilayer substrate 11a are
1a, they are connected by a via-hole electrode Vh1a.

FIG. 6 is a sectional view of another modification of the band rejection filter of FIG. The band rejection filter 10b is configured as shown in FIG.
As compared with the band rejection filter 10 of the embodiment, the series-coupled capacitors 5 and 6 (FIG. 1) are replaced with chip capacitors C1 and C
2 and is mounted on the surface of the multilayer substrate 11b. Note that the chip capacitors C1,
C2 and the strip line electrode S inside the multilayer substrate 11a
The via holes Vh1b are connected to T11 and ST12 inside the multilayer substrate 11b.

According to the band rejection filter of the above-described embodiment, since the inter-stage coupling capacitor and the notch circuit are integrated on the multilayer substrate formed by laminating the first to eighth dielectric layers, the inter-stage coupling is realized. Each wiring of the capacitor and the notch circuit 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, the inductor of the notch circuit is constituted by a strip line electrode provided inside the multilayer substrate, and the series coupling capacitor and the inter-stage coupling capacitor of the notch circuit are opposed to each other with a dielectric layer interposed inside the multilayer substrate. Therefore, 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.

Further, in the modification shown in FIG. 5, since the inductor constituting the notch circuit is formed of a high-Q chip inductor and mounted on a multilayer substrate, the band rejection is excellent in attenuation characteristics and low in insertion loss. It is possible to obtain a filter.

In the modification shown in FIG. 6, since the series-coupled capacitors constituting the notch circuit are constituted by chip capacitors and mounted on a multilayer substrate, it is not necessary to form a capacitor electrode inside the multilayer substrate. . As a result, the thickness of the dielectric layers above and below the stripline electrode can be increased without increasing the height of the multilayer substrate,
Since the strip line electrode can be a high Q inductor, it is possible to obtain a band rejection filter having excellent attenuation characteristics and low insertion loss.

FIG. 7 is a block diagram of a general receiving module. In FIG. 7, Pi and Po are input / output terminals,
21 is a low noise amplifier, 22 is a band reject filter,
A band rejection filter 22 is connected downstream of the low noise amplifier 21.

FIGS. 8 and 9 are an exploded perspective view and a sectional view of an embodiment of the receiving module according to the present invention. The receiving module 20 includes first to ninth dielectric layers 231 to 239
, A band-stop filter 22 (FIG. 7) is built in the multilayer substrate 23, and the multilayer substrate 2
3, a low noise amplifier 21 is mounted.

A land La for mounting the low noise amplifier 21 on the multilayer substrate 23 is provided on the upper surface of the first dielectric layer 231.
Is formed. Further, a wiring line Li is formed on the upper surface of the second dielectric layer 232.

Further, the third and ninth dielectric layers 233,
The ground electrodes Gp21 and Gp22 are formed on the upper surface of the 239. Further, strip line electrodes ST21 and ST22 are formed on the upper surface of the fourth dielectric layer 234. Further, capacitor electrodes Cp21 and Cp22 are formed on the upper surface of the fifth dielectric layer 235.

On the upper surface of the sixth dielectric layer 236, capacitor electrodes Cp23 and Cp24 are formed. Further, a capacitor electrode C is provided on the upper surface of the seventh dielectric layer 237.
p25 is formed. Further, capacitor electrodes Cp26 and Cp27 are formed on the upper surface of the eighth dielectric layer 238. Further, via-hole electrodes Vh2 are formed in the first to seventh dielectric layers 231 to 237 so as to penetrate the respective dielectric layers 231 to 237.

The first to ninth dielectric layers 231 to 23
Reference numeral 9 denotes, for example, a sheet obtained by kneading a dielectric ceramic mainly composed of barium oxide, aluminum oxide and silica, which can be fired at a temperature of 850 ° C. to 1000 ° C., together with a binder and the like.

The strip line electrodes ST21, S21
T22, capacitor electrodes Cp21 to Cp27, ground electrodes Gp21, Gp22, land La and wiring line L
i is made of Ag, Pd, Ag-Pd, Cu, or the like;
To the ninth dielectric layers 231 to 239 by a known method such as a printing method, a sputtering method, and a vacuum evaporation method.

These first to ninth dielectric layers 231 to 2
39 are stacked and sintered integrally,
The multilayer substrate 23 is obtained. The ground electrode Gp21 and the strip line electrodes ST21 and ST22, and the strip line electrodes ST21 and ST22 and the capacitor electrode C
Each of p21 and Cp22 is connected via a via-hole electrode Vh2 inside the multilayer substrate 23.

The capacitor electrodes Cp23 and Cp26
The land La is connected to the via hole electrode Vh2 and the wiring line Li inside the multilayer substrate 23.

Further, on the side surface and the front and back surfaces of the multilayer substrate 23, the input terminal P is electrically connected to the low-noise amplifier 21.
i (FIG. 7) and a capacitor electrode C
p24, Cp27, and the output terminal Po
(FIG. 7), an external terminal T22 and a ground electrode Gp2.
1, external terminals T23 and T24 that are electrically connected to Gp22 and serve as ground terminals are formed. In addition, these terminals T21 to T24 are formed by a method such as a sputtering method, a vacuum evaporation method, and coating and baking.

With the above configuration, the receiving module 20 has a structure in which the band rejection filter 22 having the equivalent circuit shown in FIG. The band rejection filter 2 is formed by the strip line electrodes ST21 and ST22.
Two inductors 3, 4 (FIG. 1) are formed.

The capacitor electrodes Cp21 and Cp23 and the capacitor electrodes Cp22 and Cp24 facing each other with the fifth dielectric layer 235 interposed therebetween form the series coupling capacitors 5 and 6 (FIG. 1) of the band rejection filter 22.

Further, the sixth and seventh dielectric layers 236,
237 sandwiching the capacitor electrodes Cp2
3, Cp25, Cp26, and capacitor electrode Cp2
4, Cp25 and Cp27 form the interstage coupling capacitor 7 (FIG. 1) of the band rejection filter 22.

FIG. 10 is a sectional view of a modification of the receiving module of FIG. The receiving module 20a is different from the receiving module 20 of the embodiment of FIG.
Is mounted in a cavity 24 provided on the surface of the multilayer substrate 23a.

The cavity 24 is formed by further laminating a dielectric layer (not shown) having an opening at a position where the cavity 24 is formed on the first dielectric layer 231 in FIG. You. After the low noise amplifier 21 is mounted, the cavity 24 is sealed by filling with a resin 25.

According to the receiving module of the above embodiment,
Since the band-stop filter and the low-noise amplifier are integrated on the multilayer substrate composed of the first to ninth dielectric layers, each wiring between the band-stop filter and the low-noise amplifier can be provided inside the laminate. it can. Therefore, since the loss in each wiring can be reduced, a receiving module having good transmission characteristics can be obtained.

The inductor of the band rejection filter is constituted by a strip line electrode provided inside the multilayer substrate,
Since the series coupling capacitor and the inter-stage coupling capacitor of the band rejection filter are constituted by capacitor electrodes provided to face each other with the dielectric layer interposed therebetween in the multilayer substrate, the number of components of the band rejection filter can be reduced. Therefore, it is possible to reduce the cost and size of the receiving module including the band rejection filter and the low noise amplifier.

Further, in the modification shown in FIG. 10, since the low-noise amplifier is mounted in the cavity provided in the multilayer substrate having the built-in band rejection filter, the low-noise amplifier does not jump out of the surface of the multilayer substrate. Therefore, the possibility that the low noise amplifier is peeled off from the multilayer substrate is reduced, and the reliability of the receiving module is improved.

FIG. 11 is an RF block diagram of a portable telephone which is a general portable radio. In FIG. 11, ANT
Denotes an antenna, Rx and Tx denote receiving circuits and transmitting circuits connected to the antenna ANT via the switches SW, and 31 denotes a housing that covers the switches SW, the receiving circuits Rx and the transmitting circuits Tx.

At this time, the receiving circuit Rx includes the low noise amplifier L
The transmission circuit Tx includes a high-output amplifier PA, a band-pass filter BPF, and a mixer MIX. The mixer MIX of the receiving circuit Rx and the mixer MI of the transmitting circuit Tx
One input of X is a synthesizer S for generating a local signal.
YN is connected.

The band rejection filter 10 of FIG. 2 is used for the band rejection filter BEF of the reception circuit Rx, which is a high frequency circuit section of the mobile phone, and the reception module 20 shown in FIG. 8 is used for the low noise amplifier LNA and the band rejection filter BPF. It is.

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 transmission characteristics are used, the transmission characteristics of the portable radio are improved. 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 a ceramic 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 with a ceramic or a fluorine-based resin containing magnesium oxide or silica as a main component.

Further, the case has been described where the strip line electrode constituting the inductor, the series coupling capacitor, and the capacitor electrode constituting the inter-stage coupling capacitor are sandwiched between two ground electrodes, but the same applies if at least one ground electrode is provided. The effect of is obtained.

Further, in the above embodiment of the band rejection filter, the case of the equivalent circuit as shown in FIG. 1 has been described. However, it is sufficient that at least the interstage coupling capacitor and the notch circuit are provided. An equivalent circuit in which an inductor is connected in parallel or a capacitor is connected between the input / output terminal and the interstage coupling capacitor may be used.

In the above-described modification of the receiving module, the case where the cavity is sealed by filling the resin is described. However, the cavity may be sealed by a cap made of metal or ceramic. In this case, it becomes possible to mount the low-noise amplifier in a bare chip state or to mount other electronic components on the cap, resulting in lower cost and smaller size of the receiving module. Can be achieved.

[0062]

According to the band rejection filter of the first aspect,
Since the inter-stage coupling capacitor and the notch circuit are integrated on the multilayer substrate formed by laminating a plurality of dielectric layers, each wiring of the inter-stage coupling capacitor and the notch circuit 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.

According to the band rejection filter of the second aspect, the inductor of the notch circuit is constituted by the strip line electrode provided inside the multilayer substrate, and the series coupling capacitor and the interstage coupling capacitor of the notch circuit are disposed inside the multilayer substrate. Since it is composed of capacitor electrodes provided to face each other with a dielectric layer interposed therebetween, 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 third aspect of the present invention, since the band rejection filter and the low-noise amplifier are integrated on the multilayer substrate composed of a plurality of dielectric layers, each of the components between the band-rejection filter and the low-noise amplifier is provided. Wiring can be provided inside the laminate. Therefore, since the loss in each wiring can be reduced, a receiving module having good transmission characteristics can be obtained.

According to the receiving module of the fourth aspect, the inductor of the band rejection filter is constituted by the strip line electrode provided inside the multilayer substrate, and the series coupling capacitor and the interstage coupling capacitor of the band rejection filter are disposed inside the multilayer substrate. Since it is composed of capacitor electrodes provided to face each other with a dielectric layer interposed therebetween, the number of components of the band rejection filter can be reduced. Therefore, the cost of the receiving module including the band rejection filter and the low noise amplifier can be reduced,
Miniaturization is possible.

According to the fifth aspect of the present invention, since the low-noise amplifier is mounted in the cavity provided in the multilayer substrate having the built-in band rejection filter, the low-noise amplifier does not jump out of the surface of the multilayer substrate. Therefore,
The possibility that the low noise amplifier is peeled off from the multilayer substrate is reduced, and the reliability of the receiving module is improved.

According to the portable radio device of the present invention, a small band rejection filter having good pass characteristics is used.
Deterioration of the transmission characteristics 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 radio of the present invention, since a small receiving module having good transmission characteristics is used, it is possible to prevent the deterioration of the transmission characteristics of the portable radio. 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 general band rejection filter.

FIG. 2 is an exploded perspective view of an embodiment according to the band rejection filter of the present invention.

FIG. 3 is a sectional view of the band rejection filter of FIG. 2;

FIG. 4 is a diagram illustrating pass characteristics of the band rejection filter of FIG. 2;

FIG. 5 is a sectional view of a modification of the band rejection filter of FIG. 2;

FIG. 6 is a sectional view of another modification of the band rejection filter of FIG. 2;

FIG. 7 is a block diagram of a general receiving module.

FIG. 8 is an exploded perspective view of an embodiment according to the receiving module of the present invention.

FIG. 9 is a sectional view of the receiving module of FIG. 8;

FIG. 10 is a sectional view of a modification of the receiving module of FIG. 8;

FIG. 11 is an RF block diagram of a general mobile phone.

FIG. 12 is an exploded perspective view of a conventional band rejection filter.

[Explanation of symbols]

10, 10a, 10b, 22 Band stop filter 11, 11a, 11b, 23, 23a Multilayer substrate 111-118, 231-239 Dielectric layer 3, 4 Inductor 5, 6 Series coupling capacitor 7 Interstage coupling capacitor 8, 9 Notch Circuit 20 Receiving module 21 Low noise amplifier 24 Cavity Cp11 to Cp17, Cp21 to Cp27 Capacitor electrode ST11, ST12, ST21, ST22 Strip line electrode

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J006 HB05 HB13 HB21 HB22 JA02 LA21 LA24 NA04 NB07 NC03 5K011 AA16 DA27 JA01 KA00 KA18 5K062 AB00 BB03 BB09 BC05 BF07

Claims (7)

[Claims] 1. at least one inter-stage coupling capacitor;
A band rejection filter comprising: a plurality of notch circuits each including an inductor and a series coupling capacitor connected in cascade via the interstage coupling capacitor; and a multilayer substrate formed by laminating a plurality of dielectric layers. 2. An inductor of the notch circuit is constituted by a strip line electrode provided inside the multilayer substrate, and a series coupling capacitor and the inter-stage coupling capacitor of the notch circuit are provided inside the multilayer substrate by the dielectric material. 2. The band rejection filter according to claim 1, comprising a plurality of capacitor electrodes provided to face each other with a layer interposed therebetween. 3. at least one inter-stage coupling capacitor;
A plurality of dielectric layers comprising: a band-stop filter including a plurality of notch circuits each including an inductor and a series-coupling capacitor cascaded through the inter-stage coupling capacitor; and a low-noise amplifier connected to the band-stop filter. A receiving module, wherein the receiving module is integrated with a multilayer substrate. 4. The notch circuit of the band rejection filter, wherein the low noise amplifier is mounted on the multilayer substrate, and the inductor of the notch circuit of the band rejection filter is constituted by a strip line electrode provided inside the multilayer substrate. 4. The series-coupling capacitor and the inter-stage coupling capacitor of the band rejection filter are constituted by a plurality of capacitor electrodes provided inside the multilayer substrate and opposed to each other with the dielectric layer interposed therebetween. A receiving module according to claim 1. 5. The receiving module according to claim 3, wherein the low-noise amplifier is mounted in a cavity provided in the multilayer substrate. 6. A portable wireless device using the band rejection filter according to claim 1 or 2. 7. A portable wireless device using the receiving module according to claim 3. Description: