JP2006186906A - High-frequency module and radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein high-frequency modules must be separately designed when the high-frequency modules are manufactured corresponding to two or more systems of different frequency bands or different communication modes, so that management expenses for dielectric laminated boards are multiplied to cause troubles, such as a cost increase, a delivery delay, risks of unnecessary board stocks, etc. <P>SOLUTION: The high-frequency module is composed of a low-pass filter 13 connected to a first system and a band-pass filter 12 connected to a second system. The band-pass filter 12 is equipped with an inductor 10, a capacitor 11, and a surface acoustic wave filter 12 as surface-mounting parts. When it is unnecessary to cope with the second system, the band-pass filter 12 is set unmounted, and the inductor 10 and the capacitor 11 are replaced with a jumper resistor, whereby the same dielectric laminated boards are capable of coping with the manufacture of the high-frequency modules. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  INDUSTRIAL APPLICABILITY The present invention is used in a wireless communication apparatus, and includes a high frequency module integrally configured with a demultiplexing circuit for demultiplexing a plurality of systems having different frequency bands or communication methods, and a mobile phone equipped with the same, a wireless LAN, and a WLL (Wireless Local Loop). ) And the like.

In recent years, cellular phones have been widely used, and functions and services of cellular phones have been improved.
In particular, recently, there has been proposed a mobile phone that employs a system in which a GPS (Global Positioning System) system for acquiring position information is added to a single mobile phone in addition to a transmission / reception system. A mobile phone to which a GPS function is added uses a high-frequency demultiplexing circuit (hereinafter simply referred to as “demultiplexing circuit”) to separate a transmission / reception signal of the transmission / reception system and a transmission / reception signal of the GPS system.

For example, when a GPS system is added to a cellular phone cellular system (800 MHz band), a circuit configuration as shown in FIG. 7A is used.
A reception signal of the cellular system that has entered from the antenna terminal ANT passes through the low-pass filter LPF1 of the branching circuit. The reception signal that has passed through the low-pass filter LPF1 is an active device that includes a filter that employs a passive element having a steep frequency cutoff characteristic such as a SAW filter element for distributing the transmission signal and the reception signal, or a semiconductor switching element such as GaAs. It passes through a type changeover switch (both not shown), is input to a low noise amplifier, is amplified, and is supplied to a high frequency signal processing circuit.

The GPS reception signal (1575 MHz) passes through the band pass filter BPF1 of the branching circuit. The received signal that has passed through the band pass filter BPF1 is input to the low noise amplifier, amplified, and supplied to the high frequency signal processing circuit.
On the other hand, the transmission signal of the cellular system is transmitted to the power amplifier through a high frequency filter that passes a predetermined frequency band. The power amplifier amplifies the transmission high-frequency signal and supplies the amplified signal to the branching circuit through an output matching circuit, a filter having a sharp cutoff characteristic, or a changeover switch. The transmitted radio wave exits the demultiplexing circuit and is radiated from the antenna.
JP 2003-115748 A JP-A-9-260908

In the cellular phone configured as described above, depending on the specification, a GPS system may not be installed, and only a cellular system may be used.
In this case, a demultiplexing circuit that separates the transmission / reception signal of the transmission / reception system and the transmission / reception signal of the GPS system is not necessary. Instead, a harmonic that is an integral multiple of the fundamental frequency of the transmission / reception signal of the cellular system as shown in FIG. A low-pass filter LPF2 for attenuating the wave distortion signal is used.

As described above, since necessary circuits differ depending on the corresponding system, it is necessary to newly design a high-frequency module for the mobile phone when the corresponding system is changed.
For this reason, since each is individually designed and manufactured, there is a problem in that the management costs of the dielectric multilayer substrate are multiplexed, and problems such as an increase in cost and delay in delivery occur. In addition, when a change occurs in the market needs and the corresponding system is changed, there is a problem that a stock of dielectric multilayer substrates corresponding only to the old system remains.

An object of the present invention is to provide a high-frequency module that can cope with a change of a mounted component with exactly the same dielectric laminated substrate in accordance with a change in a corresponding transmission / reception system or reception system.
It is another object of the present invention to provide a wireless communication device equipped with the high frequency module.

  The demultiplexing circuit of the high-frequency module of the present invention includes a demultiplexing circuit for connecting a plurality of systems having different signal frequencies to one shared antenna, and the demultiplexing circuit includes a surface of a dielectric multilayer substrate, It is a circuit including a conductor wiring layer formed inside and a surface mount component mounted on the surface of the dielectric multilayer substrate. The branching circuit includes a first filter circuit connected to the first system and a second filter circuit connected to the second system. The first filter circuit includes a low-pass filter, and the second filter circuit includes an inductor, a capacitor, and a band-pass filter as surface mount components. When it is not necessary to deal with the second system, the band pass filter is not mounted, and an element having impedance is mounted instead of the inductor and the capacitor.

By adopting such a high-frequency module, one dielectric multilayer substrate is designed, manufactured, and managed, and when it is not necessary to support the second system, the mounted system is changed and the first system is changed. Can produce and sell high-frequency modules compatible only with
As a result, it is basically the market for wireless communication devices in the first system, but even if the degree of request for support for the second system is uncertain in terms of region and time, unnecessary inventory is maintained. It is possible to reduce the risks involved.

If the inductor, the capacitor, or the element having impedance is structured to be bonded to the surface layer component pad formed on the surface of the dielectric multilayer substrate by soldering, any selected element is dielectric laminated. It can be mounted on a dielectric laminated substrate by a simple process of mounting on a substrate and melting solder.
If a second capacitor is connected between the terminal on the shared antenna side of the bandpass filter and the ground, even when no response to the second system is required, the second antenna is viewed from the shared antenna terminal. Thus, the impedance of the second filter circuit becomes capacitive, and the impedance when the first filter circuit and the second filter circuit are connected is easily matched with the characteristic impedance of the signal line. Therefore, reflection of the antenna input signal can be prevented.

The element having the impedance may be a chip resistor that can be mounted on a surface layer of the dielectric multilayer substrate.
The range of the resistance value of the element having the impedance is desirably 10Ω or less. The reason for this is that if the value of the element having the impedance exceeds 10 ohms, the matching state is deteriorated rather than when the element is mounted on the dielectric laminated substrate rather than when it is not mounted. Because.

In particular, a 0 ohm element (jumper resistor) is basically used.
In addition, by configuring a high-frequency module having the structure of the branching circuit and including at least one of a duplexer, a power amplifier, a directional coupler, and a bandpass filter, it is possible to promote downsizing of the wireless communication device.
In addition, according to the present invention, by mounting the high-frequency module, it is possible to realize a small-sized and low-cost wireless communication apparatus that can easily cope with a change in the system.

As described above, according to the present invention, there is an advantage that the mass production effect can be used, and the price can be reduced and the delivery time can be shortened. In addition, design time can be reduced.
In addition, in wireless communication devices such as portable terminals, it is possible to achieve timely market introduction and cost reduction of new models.

The high-frequency module of the present invention will be described with reference to the drawings.
Hereinafter, a description will be given by taking as an example a high-frequency module that can support both a case where a CDMA cellular system and a GPS (Global Positioning System) system are shared and a case where the cellular system is used alone.
FIG. 1 is a block configuration diagram of a CDMA high-frequency module used in a wireless communication device such as a mobile phone.

This CDMA high frequency module is composed of a cellular 800 MHz band transmission / reception system and a GPS 1.5 GHz band reception system in order to use a positioning function by GPS.
In mobile radio communication devices equipped with such a band-demultiplexing circuit, there is a strong demand for miniaturization and weight reduction for each part, and considering these requirements, the demultiplexing circuit achieves desired characteristics. It is modularized in units that can be done.

That is, as indicated by the solid line 100 in FIG. 1, the surface mount components 10, 11, the band pass filter 12, the low pass filter 13, and the like are arranged on one substrate to form one high frequency module.
In addition to the surface mount components 10 and 11, the band pass filter 12, and the low pass filter 13, a duplexer that separates transmission / reception signals by a steep cutoff characteristic is mounted, a transmission filter, a power amplifier, and a directional coupler. A transmission circuit including the above may be mounted to form a larger-scale high-frequency module.

Furthermore, a high-frequency module on which a high-frequency filter for reception and a low-noise amplifier constituting the cellular reception system are mounted may be used.
FIG. 2 is a block diagram of a large-scale high-frequency module 110 having the structure of the high-frequency module 100 shown in FIG. 1 and including a duplexer 202, a power amplifier 204, a directional coupler 206, and a transmission filter 208.

Since the high-frequency module 110 of FIG. 2 has a large circuit scale, it is possible to enjoy the effects of cost reduction, short delivery time, and reduction of design time due to the mass production effect of the present invention.
Hereinafter, description will be made based on the high-frequency module having the configuration shown in FIG. However, since the part of the demultiplexing circuit of the high-frequency module in FIG. 2 is the same circuit configuration, the following description also applies to the high-frequency module in FIG.

The high-frequency module of the present invention includes an antenna terminal ANT formed on a dielectric substrate and connected to an antenna of a wireless communication device, surface mount components 10 and 11, a band pass filter (BPF) 12, and an antenna terminal ANT. Surface layer component pads 2 to 7 formed between the band pass filters 12 are provided.
The surface layer component pads 2 to 5 are pads for mounting the surface mount components 10 and 11 for selecting a system. A position between the surface layer component pads 2 and 3 is denoted by reference numeral S1, and a position between the surface layer component pads 4 and 5 is denoted by reference numeral S2. The surface mount component 10 is mounted at the position S1, and the surface mount component 11 is mounted at the position S2.

Further, the surface layer component pads 6 and 7 are pads to be connected to the input / output electrodes of the band pass filter 12. A position between the surface layer component pads 6 and 7 is indicated by a symbol S3. The band pass filter 12 is mounted at this position S3.
Furthermore, a shunt capacitor C2 formed with an inner layer conductor pattern, a low-pass filter (LPF) 13, a CELL terminal 16 connected to a transmission / reception circuit of a cellular system, and a reception circuit of a GPS system are formed in a dielectric multilayer substrate. A GPS terminal 15 to be connected is provided.

  The band pass filter 12 is a filter for attenuating a signal in the frequency band of the cellular system, passing only a received signal in the frequency band of the GPS system, and inputting / outputting to / from the GPS terminal 15. Is for attenuating a received signal in the frequency band of the GPS system and inputting / outputting a signal used in the cellular system to the CELL terminal 16.

  The band-pass filter 12 can be constituted by, for example, a surface acoustic wave filter element formed on a dielectric. Since the SAW has a characteristic that the attenuation characteristic is steep and is small, the performance of the high-frequency module can be improved and the size can be reduced by using the SAW. In place of the surface acoustic wave filter (SAW filter), surface mount components such as an FBAR filter, a dielectric filter, and a BAW filter can be used.

The low-pass filter 13 is formed of a conductor pattern formed in the inner layer of the dielectric multilayer substrate. Note that the low-pass filter 13 may be mounted on the surface of the dielectric multilayer substrate.
First, selection of components when the high-frequency module of the present invention is applied to a wireless communication apparatus that shares a cellular system and a GPS system will be described.

When sharing cellular and GPS, according to Table 1, capacitors C1 and inductors L are mounted at positions S1 and S2 of the dielectric multilayer substrate, respectively. The order of the capacitor C1 and the inductor L may be exchanged. A band pass filter such as a SAW filter is mounted at the position S3.
FIG. 3 shows a circuit diagram when the capacitor C1, the inductor L, and the band pass filter (BPF) 12 are mounted.

Next, when the cellular system is used alone, according to Table 1, jumper resistors (chip resistors having a resistance value of 0 ohm) R1, R2 are mounted at positions S1, S2 of the dielectric laminated substrate. Bandpass filters are not implemented at 12 locations.
A circuit diagram when these jumper resistors R1 and R2 are mounted is shown in FIG.
The reason why the jumper resistors R1 and R2 are mounted instead of the capacitor C1 and the inductor L instead of simply not mounting the bandpass filter 12 when the cellular system is used alone is as follows.

As shown in FIG. 3, the high-frequency module for cellular and GPS sharing includes a cellular circuit composed of LPF 13 and a GPS circuit in which a capacitor C1, an inductor L, a shunt capacitor C2, and a band-pass filter 12 are connected in cascade. Become.
Here, considering the impedance viewed from the antenna terminal ANT at the cellular fundamental frequency, the cellular side circuit has an impedance Z (Z = 50 + jX; X> 0) closer to L from 50 ohms. On the other hand, the GPS side circuit has an impedance Z (Z = ∞−jX; X> 0) from C from open (infinite ohms). The L component and the C component cancel each other, and 50 ohm matching is obtained.

  Next, if the capacitor C1, the inductor L, and the band pass filter 12 are all not mounted when the cellular is used alone, the impedance of the GPS side circuit at the cellular fundamental frequency is completely open. Then, the 50 ohm alignment which was taken at the time of cellular and GPS sharing will be destroyed. If the alignment is lost in this way, it becomes necessary to adjust the alignment again on the cellular system side. Therefore, design, characteristic adjustment, process capability confirmation, guarantee, etc. have been implemented as a high-frequency module compatible with cellular and GPS shared devices. Must be done again.

  Therefore, instead of the surface mount component capacitor C1 and inductor L, jumper resistors R1 and R2 are mounted. In this way, the impedance of the GPS side circuit with respect to the antenna terminal ANT moves from the open position to the C position due to the capacitance formed by the shunt capacitor C2 built in the dielectric multilayer substrate, and the same impedance as in the case of using both cellular and GPS is obtained. be able to. This eliminates the need to re-design, adjust the characteristics, check the process capability, and guarantee the high-frequency module for cellular and GPS shared devices, shorten delivery times, reduce board management costs, and risk of unnecessary inventory. It can contribute to reduction.

FIG. 5 is a plan view of the surface of the dielectric substrate 1 of the high-frequency module of the present invention viewed from the top in the stacking direction. FIG. 6 is a perspective view showing a state in which the surface mount components 10 and 11 and the band pass filter 12 are mounted on the surface of the multilayer dielectric substrate 1.
The laminated dielectric substrate 1 is formed by laminating a plurality of dielectric layers, and a wiring conductor layer is formed on the surface or inside thereof. For example, an organic system dielectric layer such as a glass epoxy resin is formed by forming a wiring conductor layer with a conductor such as a copper foil, laminated and thermally cured, or an inorganic system dielectric substrate green such as a ceramic material. Various wiring conductor layers are formed on a sheet, and these are laminated and fired at the same time.

  The ceramic material includes (1) a ceramic material whose main component is Al2O3, AlN, Si3N4, SiC, etc., and a firing temperature of 1100 ° C. or higher, and (2) 1100 ° C. or lower, especially 1050 ° C. or lower, made of a mixture of metal oxides. (3) at least one selected from the group of low-temperature fired ceramic materials fired at 1100 ° C. or lower, particularly 1050 ° C. or lower, made of glass powder or a mixture of glass powder and ceramic filler powder A species is selected.

  As the mixture of (2), ceramic materials such as BaO—TiO 2 system, Ca—TiO 2 system, MgO—TiO 2 system are used. A material obtained by appropriately adding an auxiliary agent such as SiO2, Bi2O3, CuO, Li2O, or B2O3 to these ceramic materials may also be used. The glass composition (3) contains at least SiO2, and contains at least one of Al2O3, B2O3, ZnO, PbO, alkaline earth metal oxide, and alkali metal oxide, Specifically, SiO2-B2O3-RO system, SiO2-BaO-Al2O3-RO system, SiO2-B2O3-Al2O3-RO system, SiO2-Al2O3-RO system, and these systems include ZnO, PbO, Pb, ZrO2 And a composition containing TiO2 and the like.

  As the glass of (3), amorphous glass can be obtained by baking treatment, and alkali metal silicate, quartz, cristobalite, cordierite, mullite, enstatite, anorthite, serdian, spinel, Crystallized glass that precipitates at least one crystal of garnite, diopside, ilmenite, willemite, dolomite, petalite, and substituted derivatives thereof is used. The ceramic filler in (3) is Al2O3, SiO2 (quartz, cristobalite), forsterite, cordierite, mullite, ZrO2, mullite, forsterite, enstatite, spinel, magnesia, AlN, Si3N4, SiC, MgTiO3. And at least one selected from the group of titanates such as CaTiO3, and it is desirable that the glass is mixed in a proportion of 20 to 80% by mass of glass and 20 to 80% by mass of filler.

  On the other hand, since the wiring conductor layer is formed by simultaneous firing with the dielectric substrate, various combinations are made according to the firing temperature of the ceramic material forming the dielectric substrate. For example, when the ceramic material is (1), a conductor material mainly containing at least one selected from the group consisting of tungsten, molybdenum, manganese, and copper is preferably used. Moreover, it is good also as a mixture with copper etc. for resistance reduction. When the ceramic material is the low-temperature fired ceramic material of (2) or (3) above, a low-resistance conductor material mainly containing at least one selected from the group consisting of copper, silver, gold, and aluminum is used.

The via-hole conductor for connecting each layer is formed by plating a through hole formed in the dielectric layer or filling a conductor paste.
In particular, if a ceramic material is used, the dielectric constant of the ceramic dielectric is usually 7 to 25, which is higher than that of the resin substrate. Therefore, the dielectric layer can be made thin, and the size of the circuit element embedded in the dielectric layer can be reduced. The distance between the elements can be reduced, and the distance between the elements can also be reduced.

In particular, the use of a ceramic material that can be fired at a low temperature, such as glass ceramics, is desirable because the conductor pattern can be formed of low resistance copper, silver, or the like, as described above.
As shown in FIG. 5, the antenna terminal ANT, the GPS terminal 15 and the like are configured by a wiring conductor layer formed in an internal dielectric layer. The low-pass filter 13 is formed by a strip line in which a wiring conductor layer is printed on an internal dielectric layer. The shunt capacitor C2 is formed by overlapping of the wiring conductor layers printed on the multilayered dielectric layers.

The components formed in these internal dielectric layers are indicated by broken lines in FIG.
On the other hand, the surface layer component pads 2 to 7 are constituted by wiring conductor layers formed on the surface of the dielectric substrate 1. “8” is a ground electrode layer formed on the surface of the dielectric substrate 1 and serves to seal the surface electrode formed on the piezoelectric substrate of the bandpass filter 12 mounted on the dielectric substrate 1 from the outside air. And serves to shield against external electromagnetic fields.

  This high-frequency module is made of a plurality of substrates, printing cream solder on the substrate, chip mounting for mounting the surface mount components 10 and 11 on the substrate, reflow for curing the solder, and individual substrates. It is made by a manufacturing process called dicing or snapping. If a resin sealing step is performed before dicing, the surface can be flattened and the user can easily mount it on the main board.

  As described above, according to the present invention, at the time of system selection, it can be easily realized only by changing the mount data when chip-mounting on the surface layer of the dielectric substrate based on Table 1. Therefore, a single substrate can serve as several types of demultiplexing circuits. As a result, the mass production effect can be used, and there is an advantage that the price can be reduced and the delivery time can be shortened. In addition, design time can be reduced.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments. For example, when the cellular system is used alone, chip resistors R1 and R2 having resistance values of 0 ohms are mounted at positions S1 and S2 of the dielectric multilayer substrate, but the resistance value is strictly 0 ohms. It is not limited. Resistors having resistance values up to 10Ω can be used. If the resistance value exceeds the above numerical value, the effect of the actual resistance due to the resistance value is greater than the shift to capacitance due to C2, and there is a disadvantage that mounting the resistance value has an adverse effect from the point of matching adjustment. .

Further, instead of the resistor, an element having an inductor component may be used.
Moreover, although the high frequency module corresponding to a cellular system (800 MHz band) and a GPS system was demonstrated, the pass band and communication system to which this invention is applied are not necessarily limited to these. For example, the component selection structure of the present invention can also be applied to a high-frequency module corresponding to a GSM system (Global System for Mobile communication) 800 MHz and a GPS system. In addition, various modifications can be made within the scope of the present invention.

It is a block diagram of the high frequency module of this invention carrying a branching circuit. It is a block diagram of a larger-scale high-frequency module of the present invention in which a duplexer, a power amplifier, and the like are mounted together with a branching circuit. It is a circuit diagram of the branching circuit at the time of cellular and GPS sharing. It is a circuit diagram of a demultiplexing circuit when used in a cellular system alone. It is the top view which looked at the surface of the lamination dielectric substrate 1 of a high frequency module from the lamination direction upper surface. FIG. 2 is a perspective view showing a state where the surface mount components 10 and 11 and the band pass filter 12 are mounted on the surface of the laminated dielectric substrate 1. It is a block diagram of the high frequency module carrying the conventional branching circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dielectric laminated substrate 2-7 Surface layer component pad C2 Shunt capacitor built in substrate 10, 11 Surface mount component 12 Band pass filter 13 Low pass filter 15 GPS terminal 16 Cellular terminal

Claims (8)

A high-frequency module including a branching circuit for connecting a plurality of systems having different signal frequencies to one shared antenna,
The branching circuit is a circuit including a surface of a dielectric multilayer substrate and a conductor wiring layer formed therein and a surface mount component mounted on the surface of the dielectric multilayer substrate.
A first filter circuit connected to the first system and a second filter circuit connected to the second system;
The first filter circuit includes a low-pass filter,
The second filter circuit includes an inductor, a capacitor, and a band pass filter as surface mount components,
The high-frequency module according to claim 1, wherein when the second system is not required, the band-pass filter is not mounted, and an element having an impedance is mounted instead of the inductor and the capacitor.   The high-frequency module according to claim 1, wherein the inductor, the capacitor, or the element having impedance can be joined to a surface layer component pad formed on the surface of the dielectric multilayer substrate by soldering.   The high frequency module according to claim 1, wherein a second capacitor is connected between a terminal on the shared antenna side of the band pass filter and the ground.   4. The high-frequency module according to claim 1, wherein the element having impedance is a chip resistor that can be mounted on a surface layer of the dielectric multilayer substrate. 5.   The high-frequency module according to any one of claims 1 to 4, wherein a resistance value range of the element having impedance is 10Ω or less.   6. The high frequency module according to claim 5, wherein the range of the resistance value of the element having impedance is basically 0 ohm.   The high frequency according to any one of claims 1 to 6, further comprising at least one of a duplexer, a power amplifier, a directional coupler, and a band-pass filter connected to the first filter circuit. module. A wireless communication device such as a mobile phone on which the high frequency circuit module according to claim 1 is mounted.

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