JP4399755B2 - High frequency switch module - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a multiband high-frequency switch module that handles a plurality of transmission / reception systems having different passbands, and more particularly to a structure of a metal case surrounding a chip element or a high-frequency functional component mounted on a laminate.
[0002]
[Prior art]
In recent years, the spread of mobile phones has been remarkable, and the functions and services of mobile phones have been improved. As this new mobile phone, a dual-band or triple-band mobile phone has been proposed. These mobile phones handle two or three transmission / reception systems, each of which has a signal path corresponding to the frequency and a high frequency circuit configured by using a branching circuit and a switch circuit as a switch for switching a plurality of frequencies. A switch module is used.
[0003]
For example, a high-frequency switch module disclosed in Japanese Patent Application Laid-Open No. 11-225088 is a laminate in which transmission lines of a demultiplexing circuit, a low-pass filter circuit, and a switch circuit are configured in a dielectric layer and are integrally consolidated in order to reduce the size. And a one-chip structure in which chip elements such as diodes and chip capacitors are mounted on the laminate. Further, each terminal electrode and ground terminal are formed on each side surface of the laminated body 80 as shown in FIG. 7 so as to be surface-mounted, and are further provided with lands 81, 82. The metal case 90 surrounding the mounted components such as chip elements and mainly serving as an electromagnetic wave shield is fixed to the land 82 of the ground terminal on the upper surface of the laminate by soldering.
[0004]
[Problems to be solved by the invention]
In such a high-frequency module, further integration of functions has been promoted. For example, it has been proposed to consolidate band-pass filter circuits, which have been conventionally arranged at the subsequent stage of the high-frequency module, into a one-chip laminate. ing. Currently, a surface acoustic wave element (SAW) packaged exclusively is used as this band-pass filter circuit. Specifically, two to three SAW filters are mounted on the upper surface of the laminate. However, even in this case, since it is desired that the area of the laminate (mounting effective area) is the same as that of the conventional one, the chip elements are forced to have an extremely strict arrangement configuration. For example, the module shown in FIG. 7 has a structure in which a metal case is fixed to the land on the upper surface of the laminated body. However, with such a structure, the distance between the land and the chip element becomes too close, and a short circuit due to a solder bridge occurs. There is also a fear that there is a problem that high frequency characteristics deteriorate due to electromagnetic interference. Such a problem is likely to become prominent in the future where further miniaturization is desired.
[0005]
Further, the lands of the conventional ground terminal are provided at intervals so as to sandwich the terminals of each transmission / reception system. Therefore, since the metal case tips 83, 84, 85, 86,... Are intermittently brought into contact with each other and soldered, the position of the metal case may be slightly shifted. In addition, the contact area may not be sufficient, the ground current path may become unstable, or the electromagnetic field distribution may change to change the high-frequency characteristics. In particular, the influence becomes remarkable in a high frequency band such as a microwave band and a millimeter wave band.
Further, when a package type SAW filter is mounted, the height reduction is hindered, and since the SAW filter is originally sensitive to external force and temperature change, it is desirable to keep a space around the package.
[0006]
As described above, the present invention achieves a reduction in height by making the best use of the effective mounting area of the laminated body in a high-frequency module mounted with a chip element and a SAW filter. It is another object of the present invention to provide a high-frequency switch module that can reduce the noise and protect the SAW filter externally to ensure the grounding.
[0007]
[Means for Solving the Problems]
The present invention is configured with implementing mounted components on the main surface of the product layer body formed of the transmission lines and capacitors in the electrode pattern therein, by placing a metal case covering said mounting component, a filter circuit and the switching circuit a high-frequency switch modules, the laminated body is not provided with the side electrodes, wherein the main surface of the laminate, a ground terminal, Rutotomoni land provided mounting component is mounted, wherein the metal case is the main Mounted on the surface and connected to the ground terminal, the metal case has an opening for preventing a short circuit between the top plate and the projecting portion projecting from the top plate to the main surface side of the laminate, and an adjacent mounting component. And the protrusion is solder-connected to the ground terminal.
In the present invention, it is preferable that the land provided on the opening side of the metal case is formed to the vicinity of the side surface of the laminate as compared with the land on the projecting portion side. In addition, the internal electrode pattern of the multilayer body, the chip element mounted on the main surface, and the terminal electrodes provided on the bottom surface of the multilayer body are all connected through the through holes formed in the multilayer body. Is preferred.
A ground electrode is formed on almost the entire inner layer on the bottom surface side of the laminate, and is connected to the metal case through a through hole.
[0008]
As described above, since terminals other than the ground terminal are not provided on the upper surface of the laminated body, there is no problem of interference with the chip element and the like, and the high frequency characteristics are stabilized. In addition, one end of the metal case is in surface contact with the ground terminal, and the ground is sufficiently taken to stabilize the current path. On the other hand, the other end on the SAW filter side is open, and a space is formed around the SAW filter so that it is not affected by external force or temperature. In addition, since the appearance of the module can be identified by looking at the case, there is no mistake in assembling on the substrate, for example.
[0009]
In each of the circuit configurations described above, the branching circuit is composed of an LC circuit, the switch circuit is composed mainly of a diode and a transmission line, the filter circuit is composed of a SAW filter, and the matching circuit is composed of a capacitor or an LC circuit. Also, it is desirable that the LC circuit of the branching circuit and the transmission line of the switch circuit are configured by electrode patterns in a dielectric laminate.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 to 5 show a high-frequency switch module according to an embodiment, and FIG. 1 is a perspective view in which a metal case is mounted on a laminate. FIG. 2 is a partial cross-sectional view seen from the side. FIG. 3 is a perspective view showing the laminate of the example. FIG. 4 is a plan view showing the back surface of the laminate. FIG. 5 is a perspective view showing a state in which chip elements and SAW filters are mounted on the laminate. FIG. 6 is a development view of a green sheet showing an example of the internal structure of the laminate.
[0011]
In this embodiment, an EGSM900 (Extended Global System for Mobile Communications 900) system is used as a first transmission / reception system, and a GSM1800 system is used as a second transmission / reception system. A circuit, a switch circuit that switches between a transmission system and a reception system for each transmission / reception system, a filter circuit that passes a specific signal of each reception system of the switch circuit, and a matching circuit between the switch circuit and the filter circuit. Take a dual-band high-frequency switch module integrated in a chip stack as an example. The high-frequency switch module 1 includes a transmission line for a demultiplexing circuit, a low-pass filter circuit, and a switch circuit in a multilayer body, and a diode, a chip capacitor, and a SAW filter are mounted on the top surface of the multilayer body, as will be described below slightly. Is configured. Moreover, the metal case 3 which covers mounting components, such as a SAW filter, is provided.
[0012]
First, the internal structure of the laminate 2 will be briefly described. For this laminate 2, a green sheet made of a ceramic dielectric material that can be fired at a low temperature is prepared, and a desired electrode pattern is formed thereon by printing a conductive paste mainly composed of Ag. Note that a plurality of the same electrode patterns are formed in parallel on the sheet. Such sheets are appropriately laminated and thermocompression bonded, and then cut into chips. And this chip | tip is united and the laminated body 2 is obtained.
[0013]
As shown in Fig. 6, the internal structure of Laminate 2 is a green sheet from (2) to (18) (numbers above 10 are parenthesized), and (2) is the bottom layer and is laminated in order. is there. Green sheet (1) indicates the back side of (2). A ground electrode 61 is formed on almost the entire surface of the lowermost green sheet {circle around (2)}, and elongated ground terminals 60 are formed on the left and right sides through a plurality of through holes 63. As shown in FIG. 4, the other terminals are provided with a GSM1800 transmission TX terminal 51, a voltage VC1 terminal 52, a ground terminal 53, a voltage VC2 terminal 54, and a GSM1800 reception RX terminal 55 on the side surfaces in the longitudinal direction. . Further, an EGSM900-based reception RX terminal 57, a ground terminal 58, a common antenna terminal 59, a ground terminal 60, and an EGSM900-based transmission TX terminal 61 are formed on the upper portions facing each other. These terminal electrodes are mounted on the substrate via solder electrodes.
In addition, the through hole 63 on the left end (the side on which the chip element is mounted) facing the green sheet is provided with a plurality of through holes 63 (reference numerals omitted) in all the green sheets that overlap therewith. An elongated ground terminal 66 is formed on the upper green sheet 18 through a through hole 63.
[0014]
Next, a green sheet (3) having a plurality of capacitor electrodes 62 formed thereon, and a green sheet (4) having a ground electrode 61 formed thereon are laminated. Further, the green sheets (5), (6), (7), (8), (9), and (10) above are appropriately provided with a line electrode 64, a capacitor electrode 62, a through hole (reference numerals are omitted, hereinafter referred to as other electrodes). The EGSM900 transmission line and the capacitor are arranged on the upper side of the green sheet, and the GSM1800 transmission line and the capacitor are arranged on the lower side. The green sheets (4), (5), (6), (7), (8), (9), (10) constitute a substantially low-pass filter circuit, and the green sheets (2), (3), (4), (5), (6), (7), (8), (9), (10) constitute the switch circuit.
[0015]
Next, a capacitor electrode and a line electrode are formed on the left side above the green sheet (11), and a land connection part of the SAW filter is formed on the right side. The green sheets (11), (12), (13), (14), (15), and (16) constitute almost the branching circuit, and the wiring pattern is formed on the green sheet (17). The green sheet (18) is formed with land connection portions and ground terminals 66 for diodes and chip capacitors. As shown in FIG. 3, a pair of lands 67 for diode connection and a pair of lands 68 for chip capacitor connection are formed on the left side of the top surface of the multilayer body, and a stepped portion 20 is provided on the right side. In addition, four lands 65 for connecting the SAW filter are formed in parallel.
[0016]
FIG. 5 shows a situation in which chip elements and SAW filters are mounted on the upper surface of the laminate 2. That is, the diodes 41, 42, 43, 44, the chip resistor 45, and the chip capacitors 46, 47 are soldered to the above-described pair of lands, and the package type SAW filters 48, 49 are disposed on the lands of the stepped portion 20. Is placed by soldering. The outer dimensions of this laminate are as small as about 6.6 × 4.9 × 0.9 mm, and there is no room for the effective mounting area on the upper surface of the laminate. Therefore, the land of the side terminals is eliminated, and the gap between the chip elements is minimized and the arrangement is high. Further, the SAW filter is provided on the stepped portion 20 so as to balance the height direction with the height of the chip element, thereby reducing the height.
[0017]
Next, the metal case 3 surrounding these mounted components has a wide, substantially T-shaped projecting portion 31 at one end, and this projecting portion 31 abuts on the ground terminal 66 on the upper surface of the laminate and is soldered. Fixed. Moreover, the other end side of the case has an opening 34 and has a pair of projecting portions 32 and 33 on the side surface side. The protrusions 32 and 33 are set to a length sufficient to ensure a gap g on the upper surface of the SAW filter, and are in contact with the ground land of the SAW filter provided at the stepped portion 20 by soldering. Is done. The opening 34 may have some wall portions. As a result, the case end on the SAW filter side is opened, so that a sufficient space is formed and the temperature characteristics of the SAW filter are hardly affected, and the directionality of the module body can be identified. The metal case can be securely grounded and the current path can be stabilized.
[0018]
Another embodiment of the present invention can be similarly applied to a triple band high frequency switch module. Further, the SAW filter does not necessarily need to be a package type, and can be a bare chip.
[0019]
【The invention's effect】
According to the present invention, since the side surface terminal and the land thereof are not provided on the upper surface of the laminate, the interference with the chip element is reduced. In addition, since the metal case has a large grounding area and can be taken reliably, it is stable to ground. Moreover, since one end of the case was opened, adverse effects due to temperature were suppressed. As described above, a high-frequency switch module having good electrical characteristics can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a high-frequency switch module according to the present invention, in which a metal case is mounted on a laminate.
FIG. 2 is a partial cross-sectional view seen from the side.
FIG. 3 is a perspective view showing the laminated body of FIG.
FIG. 4 is a plan view showing the back surface of the laminated body.
FIG. 5 is a perspective view after a chip element and a SAW filter are mounted on the laminate.
FIG. 6 is an example of an internal structure diagram of a laminated body.
FIG. 7 is a perspective view showing an example of a conventional high-frequency switch module.
[Explanation of symbols]
1: High frequency switch module 2: Laminated body 3: Metal case 20: Stepped portion 21, 22: Side surface in the width direction of the laminated body 23: Back surface of the laminated body 24: Side surface in the longitudinal direction of the laminated body 31: T-shape of the metal case Protrusions 32 and 33: Protrusions of a pair of metal cases 34: Metal case openings 41, 42, 43, 44: Diode 45: Chip resistors 46, 47: Chip capacitors 48, 49: Package type SAW filters 51-62 : Each terminal on the back of the laminate

Claims (4)

With implementing mounted components on the main surface of the internal electrode pattern product layer body formed of the transmission lines and capacitors, by placing a metal casing covering the mounting part, the high-frequency switch module configured to filter circuit and the switching circuit Because
The laminated body is not provided with the side electrodes, wherein the main surface of the laminate, a ground terminal and, Rutotomoni land is provided mounting component is mounted, wherein the metal case is mounted on the primary surface ground Connected to the terminal,
The metal case includes a top plate, a protrusion protruding from the top plate toward the main surface of the laminate, and an opening that prevents a short circuit between adjacent mounting components, and the protrusion is solder-connected to the ground terminal. A high-frequency switch module characterized by that.   2. The high frequency switch module according to claim 1, wherein the land provided on the opening side of the metal case is formed closer to the side of the laminated body than the land on the protrusion side. The internal electrode pattern of the multilayer body, the chip element mounted on the main surface, and the terminal electrode provided on the bottom surface of the multilayer body are all connected through a through hole formed in the multilayer body. The high frequency switch module according to claim 1 or 2.   4. The ground layer is formed on an almost entire surface of the inner layer on the bottom surface side of the multilayer body, and is connected to the metal case through a through hole. 5. High frequency switch module.

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