JP2002325048A - Front end module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front end module of a mobile communication unit being used in a plurality of communication systems and arranged such that crosstalk can be reduced between a diplexer section and a switch section. SOLUTION: At least a part of passive elements at a section 17 for switching an antenna between a transmitting circuit and a receiving circuit of relevant system, and at least a part of passive elements at a diplexer section 7 interposed between the switch section and the antenna are incorporated in a multilayered body 8 comprising conductors and dielectrics. The dielectric is composed of resin or a mixed material of resin and dielectric powder. The switch section 17 and the diplexer section 7 are spaced apart from each other in the laying direction. A low permittivity layer 9b is interposed between the switch section 17 and the diplexer section 7. Furthermore, a ground electrode 20 is interposed between the switch section 17 and the diplexer section 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front-end module which constitutes a circuit between a transmitting / receiving circuit and an antenna unit in a mobile communication device such as a portable telephone used for a plurality of communication systems.

[0002]

2. Description of the Related Art Japanese Patent No. 303117 discloses a portable telephone.
Japanese Patent Application Laid-Open No. 8 (1999) -1996 discloses an example in which a front end module of a mobile phone used for a single communication system is formed of a ceramic laminate, and a switch unit for transmission / reception and a filter unit are configured in one laminate. It is shown.

[0003] Also, Japanese Patent No. 2983016 discloses that
Diplexer (demultiplexing circuit) in a multi-band front-end module that handles multiple communication systems
An example is disclosed in which a transmission circuit and a switch unit for switching a communication method in a reception circuit are configured in one ceramic laminate.

[0004] In any of the laminates, the capacitors of the switch, filter, and diplexer portions are concentrated in the laminate, and the inductors are concentrated in different layers in the lamination direction.

[0005]

As described above, in the conventional front end module, since the diplexer section (filter section) and the switch section are mixed in the laminate, the capacitors and the transmission lines are very close to each other. Will be arranged. Therefore, there is a problem that crosstalk occurs due to the distributed capacitance and electromagnetic coupling between the capacitor electrode and the transmission line, and it is difficult to secure an attenuation characteristic for transmitting only a signal of a specific frequency. This crosstalk has a great effect on the characteristics even with a very small capacitance, especially at a high frequency of several GHz, so it is necessary to reduce it a little.

SUMMARY OF THE INVENTION In view of the above problems, the present invention makes it possible to reduce crosstalk between a diplexer unit and a switch unit in a front-end module of a mobile communication device used for a plurality of communication systems. It is intended to provide a configuration.

[0007]

According to a first aspect of the present invention, there is provided a front end module for use in a mobile communication device commonly used for a plurality of different communication systems, wherein the front end module comprises a conductor and a dielectric. Having a body, at least a part of a passive element of a switch unit for switching an antenna to a transmission circuit of a corresponding system and a receiving circuit, and at least a part of a passive element of a diplexer unit provided between the switch unit and the antenna. Embedded in the laminate made of a conductor and a dielectric, the switch unit and the diplexer unit are arranged separately in the laminating direction, and a low dielectric constant layer is provided between the switch unit and the diplexer unit. It is characterized by intervening.

As described above, if the switch section and the diplexer section are separated in the laminating direction and a low dielectric constant layer is interposed between them, crosstalk between the switch section and the diplexer section is reduced, and attenuation occurs. The characteristics can be improved.

[0009] The front end module of claim 2 is:
In claim 1, the dielectric and the low dielectric constant layer are made of a resin or a material obtained by mixing a resin and a dielectric powder.

As described above, if a resin or a material obtained by mixing a dielectric powder with a resin is used, a layer having a low dielectric constant can be easily obtained.
Attenuation characteristics suitable for a front-end module for mobile communication equipment of several GHz or more can be easily obtained.

[0011] The front end module according to claim 3 is:
In claim 1 or 2, the relative dielectric constant of the low dielectric constant layer is 2.5 to 5.0 at 1 to 2 GHz.

As described above, by setting the relative permittivity of the low-permittivity layer, crosstalk between the switch section and the diplexer section can be sufficiently reduced.

According to a fourth aspect of the present invention, there is provided a front end module comprising:
In any one of the first to third aspects, a ground electrode is further provided between the switch unit and the diplexer unit.

As described above, by further providing the ground electrode between the switch section and the diplexer section, crosstalk can be further reduced and the attenuation characteristics can be improved.

[0015]

FIG. 1 is a block diagram showing an embodiment of a front end module according to the present invention. The present embodiment shows an embodiment that is used for both the GSM system (900 MHz band) and the DCS system (1.8 GHz band). In FIG. 1, 1 is a front end module, 2 is an antenna, T1 and T5 are terminal electrodes connected to a GSM transmission circuit and a reception circuit, respectively, and T11 and T7 are DCS, respectively.
It is a terminal electrode connected to the transmission circuit and the reception circuit of the system. Arrows indicate the signal flow of each system.

Reference numerals 3 and 4 denote low-pass filters for removing harmonics contained in transmission signals of the DCS system and the GSM system, respectively, 5 a switch unit for switching the transmission and reception of the DCS system, 6 a switch unit for switching the transmission and reception of the GSM system, Reference numeral 7 denotes a diplexer provided as a demultiplexing circuit for separating a DCS signal and a GSM signal.

FIG. 2 is a circuit diagram illustrating a circuit configuration of the front end module 1. As shown in FIG. In FIG. 2, T1
T11 are terminal electrodes provided outside a laminated body 8 (see FIG. 3) described later. The terminal electrode T9 is a terminal electrode to the antenna, and the coils L1, L2, L11 and the capacitor C
1, C11 and C12 constitute the diplexer unit 7 which is a demultiplexing circuit. The circuit from the coil L1 and the capacitor C1 to the terminal electrode T11 (the circuit on the right side in the drawing) is D
This is a circuit corresponding to the CS system. A circuit from the coil L11 and the capacitor C11 to the terminal electrode T1 (the circuit on the left side in the drawing) is a circuit corresponding to the GSM system.

In the circuit corresponding to the DCS system on the right side, T11 is a terminal electrode connected to the DCS system transmission circuit. T7 is a terminal electrode connected to a DCS type receiving circuit. T8 and T10 are terminal electrodes for applying a control signal for performing DCS transmission / reception switching. The coil L6 and the capacitors C6 to C8 are
Is configured. Diodes D1, D2 and coils L3-L
5 and the capacitors C2 to C5 and C9 constitute a transmission / reception changeover switch unit 5.

In the circuit corresponding to the GSM system on the left, T1 is a terminal electrode connected to a GSM transmission circuit. T5 is a terminal electrode connected to a GSM receiving circuit. T2 and T4 are terminal electrodes to which a control signal for performing GSM transmission / reception switching is applied. The coil L14 and the capacitors C17 to C19 constitute the low-pass filter 4. The diodes D11 and D12, the coils L12 and L13, and the capacitors C13 to C16 constitute a transmission / reception changeover switch unit 6.

FIG. 3A is a sectional view showing an embodiment of the front end module according to the present invention. The front end module includes a laminate (base substrate) 8,
The diodes D1, D2, D mounted on the laminate 8
11 and mounting components 19 such as D12 and resistors R1 and R11. The laminate 8 is made of a resin in which a glass cloth is embedded or a low dielectric constant layer 9a to 9e in which a resin is mixed with a dielectric powder.
And a resin in which glass cloth is embedded or a high dielectric constant layer 10a to 10d in which a dielectric powder is mixed with a resin is provided between the inductor conductors 11, 14 and the capacitor electrodes 12, 15 between the respective layers.
And are integrally laminated. Reference numeral 16 denotes a ground electrode formed on the bottom surface of the laminate 8. The laminated body 8 constitutes a diplexer section 7 in an upper layer, and a section (hereinafter, referred to as a switch section) 17 which becomes a switch section 5 and 6 including low-pass filters 3 and 4 in a lower layer. The passive elements formed in these parts 7, 17 are the capacitors C shown in FIG.
1 to C19 and inductors L1 to L14, that is, at least a part of passive elements of the diplexer unit 7 and the switch unit 17.

As described above, the diplexer section 7 and the switch section 17 are separated from each other in the stacking direction, and the low dielectric constant layer 9b is interposed therebetween to reduce the capacitive coupling. In addition,
In FIG. 3A, the layer denoted by 10b may be a low dielectric constant layer, and by making this layer a low dielectric constant layer,
The effect of reducing capacitive coupling is further enhanced. On the uppermost layer, a low dielectric layer 9a is formed to reduce the capacitive coupling between the diplexer section 7 and the mounted component 19 or the conductor pattern. The upper and lower layers of the inductor conductor 14 serve as low dielectric layers 9c to 9e to reduce capacitive coupling with the capacitor electrode 15 and the ground electrode 16.

The low dielectric layers 9a to 9e preferably have a relative dielectric constant of 2.5 to 5.0 (measurement frequency is 1 to 2 GHz).
This is the case for z, and the following relative dielectric constants are all measured values at this frequency. ). The high dielectric constant layers 10a to 10d preferably have a relative dielectric constant of 15.
The thing of 0-30.0 is used. In the present embodiment, for the low dielectric layers 9a to 9e, a vinylbenzyl resin in which a flame retardant is mixed and glass cloth is embedded, having a relative dielectric constant of 3.5 and a thickness of 100 μm is used. For the high dielectric layers 10a to 10d, an epoxy resin mixed with a dielectric powder made of barium titanate and a flame retardant and having a glass cloth embedded therein and having a relative dielectric constant of 20 and a thickness of 60 μm was used.

As the composite material composed of a resin containing a dielectric powder, a material obtained by adding a dielectric powder and a solvent such as toluene to a resin and kneading the mixture to form a paste or a sheet is used.

Examples of the resin include, in addition to the above, phenol resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin (PPE), unsaturated polyester resin, vinyl ester resin, polyimide resin, fumarate resin, polybutadiene resin, At least one of aromatic polyester resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene sulfide resin, polyethyl ether ketone resin, polytetrafluoroethylene resin, polyarylate resin or graft resin; Used.

As the dielectric powder to be mixed with these resins, in addition to the above, for example, CaTiO ₃ based, SrT
iO ₃ system, BaTiO ₃ -BaZrO ₃ system, BaO-T
iO ₂ —Nd ₂ O ₃ system, BaO-4TiO ₂ system, BaO
—TiO ₂ —SnO ₂ system, PbO—CaO system, TiO ₂
System, BaTiO ₃ system, PbTiO ₃ system, Al ₂ O ₃ system,
BiTiO ₄ system, MgTiO ₃ system, (Ba, Sr) Ti
O ₃ system, Ba (Ti, Zr) O ₃ system, BaTiO ₃ —S
iO ₂ system, BaO-SiO ₂ system, CaWO ₄ system, Ba
(Mg, Nb) O ₃ system, Ba (Mg, Ta) O ₃ system, B
a (Co, Mg, Nb) O ₃ system, Ba (Co, Mg, T)
a) O ₃ system, Mg ₂ SiO ₄ system, ZnTiO ₃ system, Sr
ZrO ₃ system, (Zr, Sn) TiO ₄ system, BaO-Ti
O ₂ -Sm ₂ O _{3 based, PbO-BaO-Nd 2 O} 3 -T
iO _{2 system, (Bi 2 O 3, PbO} ) -BaO-TiO 2
System, La ₂ Ti ₂ O ₇ system, Nd ₂ Ti ₂ O ₇ system, (L
i, Sm) TiO ₃ system, Ba (Zn, Ta) O ₃ system, B
a (Zn, Nb) O ₃ or Sr (Zn, Nb) O
_A dielectric material composed of at least one of the _three types or the like, a metal powder having a dielectric film, or the like is used. Of course, the dielectric powder and resin used in the present invention are not limited to these materials.

Further, a mixture of a magnetic material powder and a resin may be used.

This laminate is prepared by attaching a copper foil to a prepreg made of the composite material, semi-curing and etching so as to form a conductor pattern for a plurality of laminates, and then newly adding a prepreg, The process of attaching a copper foil and etching may be repeated, or a thick-film printing method or a thin-film forming method may be used for a build-up method without using a glass cloth or a conductor. It is also possible to realize a sintered body using a ceramic material by a printing method or a sheet laminating method.

FIG. 4A shows the attenuation characteristic of the circuit from the terminal electrode T1 to the antenna 2 side in the GSM system as shown by the arrow 22 in FIG. 4B, according to the embodiment shown in FIG. Form, a diplexer section 7 and switch sections 5 and 6
FIG. 3 is a diagram showing a conventional configuration in which the above is mixed with a conventional configuration. In the figure, f1 indicates a center frequency to be passed, and f1
2 and f3 are frequencies corresponding to harmonics generated in the transmission circuit, respectively.

As shown in FIG. 4A, in the case of the present invention, since the capacitive coupling between the switch section 17 and the diplexer section 7 is reduced, much better attenuation characteristics can be obtained as compared with the conventional example. . According to the present invention, the arrow 2 in FIG.
As shown in FIG. 3, the attenuation characteristics of the circuit from the antenna 2 side to the terminal electrode T5 are similarly improved.

FIG. 3B shows another embodiment of the present invention, in which not only the low dielectric layer 9b is formed between the diplexer section 7 and the switch section 17 but also the ground electrode 20 is formed.
Is interposed. According to the present embodiment, the capacitive coupling between the diplexer unit 7 and the switch unit 17 can be further reduced, and the crosstalk can be further reduced.

The present invention can be suitably used for a front-end module of a mobile communication device used in a frequency range exceeding 2 GHz.

[0032]

According to the first aspect of the present invention, the switch section and the diplexer section are separated in the laminating direction, and the low dielectric constant layer is interposed therebetween, so that the crosstalk between the switch section and the diplexer section is achieved. And the attenuation characteristics of the front-end module can be improved.

According to the second aspect, since a resin or a material obtained by mixing a dielectric powder with a resin is used as the dielectric or the low dielectric layer constituting the laminate, a layer having a low dielectric constant can be easily obtained. Attenuation characteristics suitable for a front-end module for mobile communication devices of GHz or higher can be easily obtained.

According to the third aspect, since the relative dielectric constant of the low dielectric constant layer is set to 2.5 to 5.0 at 1 to 2 GHz, crosstalk between the switch section and the diplexer section is sufficiently reduced. And the damping characteristics can be further improved.

According to the fourth aspect, since the ground electrode is further provided between the switch section and the diplexer section, crosstalk can be further reduced and the attenuation characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a front end module of the present invention.

FIG. 2 is a circuit diagram of the front end module of FIG. 1;

FIGS. 3A and 3B are cross-sectional views showing an embodiment of the present invention.

4A is a diagram illustrating a comparison between attenuation characteristics of an embodiment of the present invention and a conventional example, and FIG. 4B is a diagram illustrating a flow of a signal for measuring the attenuation characteristics.

[Explanation of symbols]

1: front end module, 2: antenna, 3,
4: low-pass filter, 5, 6: switch section, 7: diplexer section, 8: laminated body, 9a to 9e: low dielectric constant layer, 1
0a to 10d: high dielectric constant layer, 11, 14: inductor conductor, 12, 15: capacitor electrode, 16: ground electrode, 17: switch section, 19: mounted component, 20: ground electrode

Claims (4)

[Claims] 1. A front-end module for use in a mobile communication device commonly used for a plurality of different types of communication systems, comprising: a laminated body composed of a conductor and a dielectric; At least a part of the passive element of the switch unit that switches to the receiving circuit and at least a part of the passive element of the diplexer unit provided between the switch unit and the antenna are built in the laminate including the conductor and the dielectric. The switch unit and the diplexer unit are separated from each other in a stacking direction, and a low dielectric constant layer is interposed between the switch unit and the diplexer unit. 2. The front end module according to claim 1, wherein the dielectric and the low dielectric constant layer are made of a resin or a material obtained by mixing a resin and a dielectric powder. 3. The front end module according to claim 1, wherein a relative dielectric constant of the low dielectric constant layer is 2.5 to 5.0 at 1 to 2 GHz. 4. The front end module according to claim 1, further comprising a ground electrode provided between said switch section and said diplexer section.