JP4565374B2 - High frequency switch module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency composite component used in a high-frequency band such as a quasi-microwave band, and relates to a high-frequency switch module that handles a transmission / reception system with at least one antenna.
[0002]
[Prior art]
In recent years, the development of mobile communication devices represented by mobile phones and the like has been remarkable. As a high-frequency component used in this mobile communication device, there is a high-frequency switch used for switching the connection between the antenna and the transmission circuit and the connection between the antenna and the reception circuit. This high-frequency switch is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-108301, and includes a diode disposed between the transmission circuit and the antenna, and a λ / 4 phase line disposed between the antenna and the reception circuit, The receiving circuit side of the λ / 4 phase line is grounded via a diode, thereby constituting a λ / 4 type switching circuit that switches a signal path by a bias current flowing through each diode. In addition, there is a high-frequency switch module in which such a λ / 4 type switch circuit is integrated with a laminated body using a low-temperature sintered dielectric ceramic material (see, for example, JP-A-6-197040).
These high-frequency switches handle only one transmission / reception system (for example, GSM-Glabal System for Mobile Communications, DCS-Digital Cellular System, PCS-Personal Communications Service, etc.). A high-frequency switch module (for example, Japanese Patent Application Laid-Open No. 11-225089) configured using a duplexer and a high-frequency switch has also been developed.
[0003]
[Problems to be solved by the invention]
FIG. 7 is an external perspective view of a conventional high-frequency switch module. This high-frequency switch module handles two transmission / reception systems of GSM and DCS, and includes a duplexer, two high-frequency switches, and a low-pass filter as in an equivalent circuit shown in FIG. A high-frequency component (diodes DP1, DP2, DG1, DG2) constituting these is mounted on a 6750-shaped multilayer substrate obtained by laminating a plurality of dielectric layers, and a transmission line and a capacitor are built in the multilayer substrate. . Some capacitors CG1 and CG2 are mounted as chip components.
In this high-frequency switch module, the resistors, inductors, etc. in the equivalent circuit are not built in or mounted on the multilayer substrate, but are arranged on the circuit substrate on which the high-frequency switch module is mounted. Built-in or built-in.
[0004]
FIG. 9 is an exploded plan view of the laminated substrate. In the vicinity of the first main surface (second layer) of the multilayer substrate on which the high-frequency component is mounted, a connection line SL for connecting the high-frequency component, the transmission line, and the capacitor is formed. Transmission lines LF1, LF2, and LF3 constituting the duplexer and LP3 and LG3 constituting the low-pass filter are formed in the fourth layer, and capacitors CF1, CF2, and CP6 of the duplexer are formed in the fifth layer.
As described above, since the connection line and the transmission line are arranged very close to each other, there is a problem that when the high-frequency switch module is reduced in size, desired electrical characteristics cannot be obtained due to electromagnetic interference.
[0005]
In addition, the high-frequency switch and the capacitor constituting the low-pass filter are formed in the substantially central region of the multilayer substrate from the fifth layer to the ninth layer.
The connection between the high-frequency component mounted on the first main surface of the dielectric substrate, the capacitor built in the multilayer substrate, and the transmission line is a through hole (indicated by black circles in the figure) or the first and second of the multilayer substrate. This is performed by an external electrode formed on the main surface and the side surface connecting the main surfaces. In the conventional high frequency module, the capacitors CP6 and CG6 connected to the switching elements DG2 and DP2 for grounding the reception circuit side of the transmission lines LG2 and LP2 disposed between the antenna of the high frequency switch and the reception circuit, and the high frequency component For example, the capacitor CG6 is connected through through holes formed in the first to seventh layers, and the capacitor CP6 is connected through through holes formed in the first to fourth layers. .
In the high-frequency switch, when GSM and DCS are transmitted, the switching elements DG2 and DP2 are appropriately turned on and grounded in high frequency, so that conductor resistance loss can be avoided in the connection between the switching element and the capacitor. It is preferable to connect at a short distance in order to improve electrical characteristics. However, in the conventional high-frequency switch module, since the capacitor is formed in the substantially central region of the multilayer substrate, it is necessary to take a long connection distance with the high-frequency component, and as a result, it is difficult to improve the electrical characteristics. there were.
[0006]
In general, a component used in a high-frequency circuit in which the high-frequency switch module is used has a characteristic impedance value of 50Ω. Therefore, it is ideal to design the high frequency switch so that the characteristic impedance is 50Ω in the vicinity of the frequency of the received signal. This characteristic impedance is determined by the distance from the ground electrode, the width of the transmission line, etc. If the characteristic impedance of the high frequency switch is set to 50Ω as the size and height of the high frequency switch module progresses, Since the distance between the ground electrodes is reduced, the transmission lines LP2 and LG2 of the high-frequency switch have to be narrowed. As a result, the resistance of the transmission line is increased, resulting in a problem of increasing resistance loss.
Accordingly, the present invention has been made to solve such problems, and an object of the present invention is to obtain a high-frequency switch module that can be miniaturized while maintaining electrical characteristics.
[0007]
[Means for Solving the Problems]
The present invention includes a high-frequency switch including a high-frequency component, a transmission line, and a capacitor, and includes a first and second main surfaces facing each other and a side surface connecting the main surfaces, each of which is formed by laminating a plurality of dielectric layers. A high-frequency switch module laminated and integrated on a multilayer substrate, wherein the high-frequency component is mounted on the multilayer substrate, the transmission line and the capacitor are built therein, and the high-frequency component mounted on the multilayer substrate and the multilayer substrate A built-in transmission line, a connection line for connecting a capacitor is disposed in a dielectric layer near the first main surface, and a ground electrode that constitutes a capacitor of a high-frequency switch between the transmission line and the connection line Is a high frequency switch module.
In the present invention, it is preferable that the high-frequency component is a switching element or a switching element and a SAW filter, and the switching element is an iodine or a field effect transistor.
The high frequency switch includes a switching element disposed between the transmission circuit and the antenna, a transmission line or a chip inductor that grounds the transmission circuit side of the switching element, and a transmission line disposed between the antenna and the reception circuit. A configuration including a switching element and a capacitor for grounding the receiving circuit side of the transmission line is preferable.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view of a high-frequency switch module of the present invention, FIG. 2 is an equivalent circuit thereof, and FIG. 3 is an exploded plan view of a multilayer substrate. In the present embodiment, a SAW filter, diodes DG1, DG2, DP1, and DP2 as well as resistors R1 and R2, capacitors CG1, CG7, CG8, CP7, and CP8 are mounted on the multilayer substrate as high frequency components of the high frequency switch. CG6 and CP6 and transmission lines LG2 and LP2 are incorporated, and a capacitor constituting the low-pass filter, a transmission line, a capacitor constituting the duplexer, and a transmission line are incorporated in the laminated substrate.
As the laminated substrate, for example, a green sheet made of an alumina glass ceramic low-temperature sintered material is prepared, and a desired electrode pattern is formed by printing a conductive paste such as Ag, Pd, or Cu on the green sheet. Are appropriately laminated and integrally fired. The thickness of the sheet is in the range of 20 to 250 μm, and is controlled by the doctor blade method or the like depending on the intended use. A large sheet in which a large number of internal electrode patterns such as predetermined capacitors, transmission lines, connection lines and the like are formed is laminated, cut into individual chip sizes, fired, and terminal electrodes are formed to produce a laminated substrate.
Terminal electrodes connected to the internal electrode pattern are formed on the surface of the multilayer substrate, and solder wettability is sufficiently obtained by applying solder plating or Au plating. A terminal electrode for mounting the high-frequency component or the like is formed on the first main surface, and a terminal electrode for connection to a circuit board on which the high-frequency switch module is mounted is formed on the second main surface. Is done. The terminal electrode formed on the first main surface is solder-printed using a metal mask, and then a PIN diode, a chip capacitor having a large capacitance value and cannot be formed in the multilayer body, a SAW filter, etc. Mount and reflow solder.
[0009]
Hereinafter, the configuration of each layer of the multilayer substrate will be described in order from the top layer.
First, on the first layer, diodes and chip components mounted on the upper surface, and terminal electrodes (lands) of SAW filters are formed. On the second layer, a connection line SL between a diode or chip component mounted on the upper surface and the internal electrode pattern is formed.
On the third layer, electrodes for capacitors CP6 and CG6 of the high-frequency switch are formed so as to be connected to the high-frequency components on the top surface at a very short distance. On the fourth layer, a ground electrode GND and another capacitor electrode CF4 constituting the capacitors CP6 and CG6 are formed. If the capacitor CP6, the electrode for CG6, the ground electrode GND, and the connection line SL are separated from each other by at least 20 μm, the influence of stray capacitance can be reduced. If the separation distance is less than 20 μm, the electrical characteristics are significantly deteriorated due to the influence of the stray capacitance.
Electrodes for capacitors CG6, CF4, and CF2 are formed on the fifth layer and the sixth layer, and transmission lines constituting a duplexer, a low-pass filter, and a high-frequency switch are formed on the seventh to twelfth layers. Yes. The transmission lines formed in this layer are preferably arranged so as not to overlap in the stacking direction except for those connected to each other.
Capacitors CG3, CG4, CF1, CP3, CP4, and CF3 electrodes are formed on the 13th and 14th layers. The capacitor formed in this layer is preferably selected and disposed so as not to be continuously connected to a mounting component such as a high-frequency component on the upper surface, or to be connected to a terminal electrode formed on the second main surface.
On the lowermost 15th layer, the ground electrode GND is formed on almost the entire surface. As a result, a stable ground can be secured.
[0010]
With the configuration as described above, the ground electrode can prevent the connection line SL and the transmission line constituting the high-frequency switch, the low-pass filter, and the like from being magnetically coupled. In addition, since the ground electrode is formed on the fourth layer, when the transmission line has a desired characteristic impedance, the distance from the ground electrode of the fifteenth layer can be ensured, and the laminated substrate can be reduced in size, particularly reduced in thickness. Even so, since the transmission line can be configured with a line width that does not affect the electrical characteristics, a compact high-frequency switch module having a 5440 shape can be obtained while maintaining the electrical characteristics.
[0011]
Next, another embodiment will be described. 4 is a component mounting plan view of the high-frequency switch module of the present invention, FIG. 5 is an equivalent circuit thereof, and FIG. 6 is an exploded plan view of the multilayer substrate. Also in the present embodiment, a SAW filter, diodes DG1, DG2, DP1, and DP2, as well as resistors R1 and R2, capacitors CG1, CG7, CG8, CP7, and CP8 are mounted on the multilayer substrate as high frequency components of the high frequency switch. CG6 and CP6 and transmission lines LG2 and LP2 are incorporated, and a capacitor constituting the low-pass filter, a transmission line, a capacitor constituting the duplexer, and a transmission line are incorporated in the laminated substrate.
[0012]
In this embodiment, capacitors CF2 and CF4 constituting the duplexer are formed from the third layer to the fifth layer together with the capacitors CG6 and CP6, and the ground electrode GND. In this embodiment, since the capacitors CG6 and CP6 are sandwiched between two ground electrodes, no parasitic capacitance is generated between the capacitor electrode and the terminal electrode on the first main surface. Even with this configuration, a small high-frequency switch module can be obtained while maintaining electrical characteristics.
[0013]
In the present invention, the laminated substrate is formed in a symmetrical manner with respect to the intermediate layer in the order of the ground electrode with the large electrode area, the transmission line layer with the small electrode area, and the ground electrode layer with the large electrode area from the lowest layer. Since the electrode layer can be arranged with a better balance than the conventional structure, it is effective in preventing deformation of the laminated substrate during sintering.
[0014]
【The invention's effect】
According to the present invention, it is possible to provide a high-frequency switch module that can cope with downsizing. This is effective for ultra-miniaturization of devices in multiband mobile phones and the like.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a high-frequency switch module according to an embodiment of the present invention.
FIG. 2 is an equivalent circuit of a high-frequency switch module according to an embodiment of the present invention.
FIG. 3 is an exploded plan view of a multilayer substrate used in one embodiment according to the present invention.
FIG. 4 is an external perspective view of a high-frequency switch module according to another embodiment of the present invention.
FIG. 5 is an equivalent circuit of a high-frequency switch module according to another embodiment of the present invention.
FIG. 6 is an exploded plan view of a multilayer substrate used in another embodiment according to the present invention.
FIG. 7 is an external perspective view of a conventional high-frequency switch module.
FIG. 8 is an equivalent circuit of a conventional high-frequency switch module.
FIG. 9 is an exploded plan view of a conventional laminated substrate.
[Explanation of symbols]
1 High-frequency switch module 2 Multilayer substrate

Claims (3)

A high-frequency switch including a high-frequency component, a transmission line, and a capacitor is stacked on a multilayer substrate having a plurality of dielectric layers stacked and first and second main surfaces facing each other and side surfaces connecting the main surfaces. An integrated high-frequency switch module, wherein the high-frequency component is mounted on the multilayer substrate, the transmission line and the capacitor are built in, and the high-frequency component mounted on the multilayer substrate and the transmission embedded in the multilayer substrate A connection line connecting a line and a capacitor is disposed in a dielectric layer near the first main surface, and a ground electrode constituting a capacitor of the high-frequency switch is disposed between the transmission line and the connection line. High frequency switch module characterized by The high-frequency switch module according to claim 1, wherein the high-frequency component is a switching element or a switching element and a SAW filter, and the switching element is a diode or a field effect transistor. The high frequency switch includes a switching element disposed between the transmission circuit and the antenna, a transmission line or a chip inductor that grounds the transmission circuit side of the switching element, and a transmission line disposed between the antenna and the reception circuit. The high-frequency switch module according to claim 1, further comprising a switching element and a capacitor for grounding the receiving circuit side of the transmission line.

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