JP2008271169A - High frequency module, and portable terminal provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small high frequency module that can be manufactured inexpensively. <P>SOLUTION: The high frequency module coping with a plurality of frequency bands has a switching circuit for switching transmission and reception, an out-of-band suppression circuit for transmission, a SAW module in which a plurality of surface acoustic wave elements corresponding to plurality of frequency bands for reception are sealed, and a substrate provided with the switching circuits, the out-of-band suppression circuit and the SAW module, wherein the SAW module has a cap part whose top face is processed to be flat, and the plurality of surface acoustic wave elements are sealed by the cap part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technology of a high-frequency module including a SAW filter and an antenna switch corresponding to a GSM system adopted for a mobile phone terminal.

  The GSM system for mobile phones that started in the European market has been deployed in the Asian and US markets due to its versatility, and the market size is expanding. Corresponding to the increase of GSM terminals, the frequency band will not be in time with the original EGSM (900 MHz) alone, DCS (1800 MHz) and PCS (1900 MHz) for high frequency bands, and GSM850 (850 MHz) for North America will be added. The market expanded rapidly.

  As the number of bands increases, the functions and functions of mobile phone terminals are increasing, and there is an increasing demand for small and low-profile devices used in mobile phones. As a technique for reducing the size and height, it is possible to delete a metal shield or a resin mold that usually covers the module.

  At that time, it is necessary to secure a flat surface at the center of the module that enables adsorption by a mounter necessary for handling in the module mounting process. For example, Patent Document 1 below proposes a method in which a plurality of SAW filters are flip-chip bonded onto a ceramic substrate and collectively sealed.

Japanese Patent Application Laid-Open No. 2002-261581

  In Patent Document 1, the flip chip bonding process for mounting the SAW filter and the sealing process for ensuring the airtightness of the SAW filter are greatly different from the mounting process of the chip component solder-mounted on the ceramic substrate. The manufacturing process becomes complicated. Therefore, there exists a subject that manufacturing cost goes up.

  An object of this invention is to provide the small high frequency module which can be produced at low cost.

  In order to achieve the above object, according to the first aspect of the present invention, a high-frequency module corresponding to a plurality of frequency bands, a switch circuit for switching between transmission and reception, a transmission out-of-band suppression circuit, and a reception A SAW module in which a plurality of surface acoustic wave elements corresponding to a plurality of frequency bands are sealed, and a substrate on which the switch circuit, the out-of-band suppression circuit, and the SAW module are provided, and the SAW module includes: There is provided a high-frequency module having a cap portion whose upper surface is processed flat, wherein the plurality of surface acoustic wave elements are sealed by the cap portion.

  The high-frequency module according to the present invention includes, for example, a SAW module in which a plurality of surface acoustic wave elements (hereinafter also referred to as SAW filters) are combined into one package (PKG). The SAW module is configured to be covered with a cap portion having a flat upper surface. The SAW module thus obtained is mounted together with other mounting components on the substrate. By making the SAW module manufacturing process different from the process of mounting the SAW module on the substrate, the manufacturing cost can be reduced.

  According to the present invention, a small and low-profile high-frequency module can be provided at low cost.

  Hereinafter, although the embodiment of the high frequency module according to the present invention is described, the present invention is not limited to the following embodiment.

  In the high-frequency module according to the present invention, a SAW module having a plurality of SAW filters mounted thereon is manufactured in the process of manufacturing the CSP SAW, and the SAW module is mounted to secure an adsorption area and can be soldered simultaneously with the chip component. It has a structure like this. Hereinafter, such a high frequency module will be described in detail.

  FIG. 1 shows a top view of an embodiment of a quad-band compatible high-frequency module according to the present invention. The high-frequency module has a SAW module 1 in which four SAW filters are combined into one PKG. The SAW module 1 is solder mounted on a ceramic substrate (LTCC) 6 together with a capacitor 2, a diode 3, an inductor 4, and a resistor 5. The

  FIG. 2 shows an example of a circuit block of a high-frequency module using the present invention. As shown in the figure, the high frequency module 7 of the present invention includes an antenna connection terminal 8, a GSM850 reception signal output terminal 9, an EGSM reception signal output terminal 10, a GSM850 / EGSM transmission signal input terminal 11, and a DCS reception signal. Output terminal 12, PCS reception signal output terminal 13, DCS / PCS transmission signal input terminal 14, switch switching control terminals 15 and 16, diplexer circuit 17, PIN diode (p-intrinsic-n Diode) 18, 19, 20, 21, λ / 4 phase shift circuits 22 and 23, resistors 24 and 25, inductors 26 and 27, ground capacitors 28 and 29, SAW filters 30, 31, 32, and 33, and LPFs (Low Pass Filters) 34 and 35.

  The received signal input from the antenna connection terminal 8 is separated into signals of 1 GHz band GSM850 and EGSM and 2 GHz band DCS and PCS by the diplexer circuit 17 so as not to affect each other. At the time of reception, by setting the switch switching control terminals 15 and 16 to off (0 V), the diodes 18, 19, 20, and 21 are turned off, and the signal separated by the diplexer circuit 17 is λ / 4 After passing through the phase shift circuits 22 and 23, input to the SAW filters 30, 31, 32 and 33, suppress unnecessary signals, and then output from any one of the received signal output terminals 9, 10, 12 and 13. The RFIC LNA (Low Noise Amplifier) connected to the subsequent stage of the high frequency module 7 is input.

  On the other hand, when GSM850 or EGSM is transmitted, the switch switching control terminal 15 is set to on. At this time, due to the voltage applied from the switch switching control terminal 15, the control current flows to the GND via the resistor 24, the diode 18, the λ / 4 phase shift circuit 22, the diode 19 and the inductor 26, and the diodes 18 and 19 are turned on. Become. The GSM850 / EGSM transmission signal input terminal 11 of the high frequency module 7 is connected to the output terminal of the transmission high power amplifier. The transmission signal output from the high-power amplifier is input to the transmission terminal 11 of the high-frequency module 7, and after the harmonic component is suppressed by the low-pass filter 34, the transmission signal passes through the diode 19 in the on state and passes through the diplexer circuit 17. Output from the connection terminal 8.

  At this time, in the receiving circuit, the diode 18 is turned on, and the λ / 4 phase shift circuit 22 and the grounding capacitor 28 are set so that the impedance of the receiving circuit viewed from the connection point between the transmitting circuit and the receiving circuit is open. By designing the constant, it is possible to reduce the amount of transmission signal leaking into the reception circuit. Similarly, when transmitting DCS or PCS, the transmission signal input from the DCS / PCS transmission signal input terminal 14 can be output from the antenna connection terminal 8 by setting the switch switching control terminal 16 to on.

  A cross-sectional view of an embodiment of the present invention is shown in FIG. Components having the same functions as those in FIG.

  In this embodiment, a multilayer ceramic substrate (LTCC) is used as the substrate 6, and the diplexer 17 and the λ / 4 phase shift circuits 22 and 23 are placed in the inner layer of the LTCC to reduce the size. A SAW module 1 on which discrete components such as a diode 3 and a chip capacitor 2 for switching transmission / reception, a chip inductor 4 and a chip resistor 5 and a plurality of SAW filters are mounted is mounted.

  Further, the SAW module 1 is mounted at a position substantially close to the center so that it can be adsorbed at a location near the center of gravity during handling in the mounting process of the high-frequency module 7. In the present invention, by using the SAW module 1 equipped with a plurality of SAW filters, it is possible to secure an adsorption area when the high-frequency module 7 is mounted, eliminating the need for further metal shielding or resin molding on the module. A space required for soldering the shield can be eliminated, and the high-frequency module 7 can be reduced in size and height.

  FIG. 4 shows one embodiment of the SAW module 1 of the present invention described in FIG. 4A is a perspective view of the SAW module, and FIG. 4B is a cross-sectional view. In the figure, 36 is a SAW chip, 37 is a ceramic substrate, and 38 is a metal cap. A plurality of SAW chips 36 are connected to a ceramic substrate (HTCC) 37 by flip chip bonding and sealed with a metal cap 38.

  The SAW module 1 can be manufactured by the same manufacturing process as the existing single-chip SAW filter, and the mounting area can be reduced by about 25% compared to the case where four single SAW filters are arranged. By mounting 1 on the high-frequency module 7, the high-frequency module 7 is further reduced in size.

  From the above description, it can be seen that the high-frequency module can be reduced in size and height using conventional manufacturing processes and equipment. Furthermore, by mounting a SAW module in which a plurality of SAW filters are combined into one package (PKG), the structure of the high-frequency module can be simplified.

  As mentioned above, although embodiment of the high frequency module according to this invention was described, this invention is not limited to the said embodiment, A various improvement and deformation | transformation can be performed in the range which does not deviate from the summary of this invention.

It is a schematic plan view which shows the example of a high frequency module structure of this invention. It is a circuit block diagram of the high frequency module of the present invention. It is a schematic sectional drawing which shows the structural example of the high frequency module of this invention. It is the schematic perspective view and schematic sectional drawing of CSP SAW used for the high frequency module of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... SAW module, 2 ... Chip capacitor, 3 ... Diode, 4 ... Chip inductor, 5 ... Chip resistance, 6 ... Ceramic substrate (LTCC), 7 ... High frequency module 8 ... Antenna connection terminal, 9 ... GSM850 reception signal output terminal, 10 ... EGSM reception signal output terminal, 11 ... GSM850 / EGSM transmission signal input terminal, 12 ... DCS reception signal output terminal , 13 ... PCS reception signal output terminal, 14 ... DCS / PCS transmission signal input terminal, 15 ... GSM850 / EGSM switch switching control terminal, 16 ... DCS / PCS switch switching control terminal, 17. Diplexer circuit, 18 to 21... Diode, 22, 23... Λ / 4 phase shift circuit, 24, 25.・ Inductors, 28, 29 ... Capacitors, 30 ... GSM850 SAW filters, 31 ... EGSM SAW filters, 32 ... DCS SAW filters, 33 ... PCS SAW filters, 34, 35 ... LPF 36 ... SAW chip, 37 ... Ceramic substrate (HTCC), 38 ... Metal cap

Claims (7)

A high-frequency module corresponding to a plurality of frequency bands,
A switch circuit for switching between transmission and reception;
A transmission out-of-band suppression circuit;
A SAW module in which a plurality of surface acoustic wave elements corresponding to a plurality of reception frequency bands are sealed;
A substrate on which the switch circuit, the out-of-band suppression circuit, and the SAW module are provided;
The SAW module has a cap part whose upper surface is processed flat, and the plurality of surface acoustic wave elements are sealed by the cap part. The high frequency module according to claim 1,
When the substrate is a first substrate,
In the SAW module, the plurality of surface acoustic wave elements are formed on a second substrate different from the first substrate,
The high-frequency module is sealed by the cap portion and the second substrate. The high-frequency module according to claim 1 or 2,
A diplexer circuit that separates signals of different frequencies;
A high-frequency module characterized in that a signal separated into a high-frequency signal and a low-frequency signal can be switched between transmission and reception, respectively. In the high frequency module according to claim 3,
The high-frequency module, wherein the switch circuit includes a Pin diode.   5. The high-frequency module according to claim 1, wherein the applicable frequency corresponds to 3 bands or 4 bands in a GSM frequency band. 6. In the high frequency module according to any one of claims 1 to 5,
The high-frequency module according to claim 1, wherein the SAW module is disposed substantially at the center on the substrate.   A portable terminal provided with the high frequency module as described in any one of Claims 1-6.

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