JP3959269B2 - High frequency circuit, composite high frequency component, and communication device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency circuit used in a communication device such as a mobile communication system, a composite high-frequency component that realizes the high-frequency circuit, and a communication device that uses the high-frequency circuit. The present invention relates to a high-frequency component and a communication device using the same.
[0002]
Currently, there are many communication systems / multiple high frequency bands as mobile communication devices. For example, TDMA systems include an EGSM (Extended Global; System; communication) communication system using a 900 MHz band and a DCS (Digital; Cellular; System) communication system using a 1.8 GHz band in Europe. A dual-band mobile phone that can be operated on the Internet has been proposed. For example, DCS and EGSM dual-band mobile phones disclosed in Japanese Patent Application Laid-Open Nos. 2001-185902 and 2000-49651 are compatible with DCS frequency bands and EGSM frequency bands. Communication is performed in the frequency band, and in other cases, communication is performed in the EGSM frequency band. In this way, by handling a plurality of standard frequency bands, when communication is impossible in one standard frequency band, communication can be performed in the other standard frequency band.
[0003]
Furthermore, for example, a triple band mobile phone capable of operating in three communication systems has been proposed, including other communication systems such as a PCS (Personal Communication Services) communication system using the 1.9 GHz band. Japanese Patent Application Laid-Open No. 2000-165288 discloses a composite high-frequency component and a mobile communication device that can operate in three communication systems.
[0004]
FIG. 1 is a block diagram illustrating a front end portion of a general triple band mobile phone, and includes a 1.8 GHz DCS and a 1.9 GHz PCS in first and second communication systems having close frequencies. FIG. 5 shows an example in which a third communication system having a frequency different from those of 900 MHz band EGSM is used.
[0005]
A composite high-frequency component 20 used in a triple-band mobile phone includes an antenna 1, a diplexer 2, first to third diode switches 3 to 5, and first and second filters 6 and 7. The diplexer 2 combines DCS, PCS, or EGSM transmission signals when transmitting, and distributes the received signals to the DCS, PCS, or EGSM when receiving. The first diode switch 3 switches between the DCS and PCS transmitter side and the DCS and PCS receiver side, and the second diode switch 4 switches between the DCS receiver Rxd side and the PCS receiver Rxp side. The switching and third diode switch 5 plays a role of switching between the transmission unit Txg side and the reception unit Rxg side of the EGSM. The first filter 6 passes the DCS and PCS transmission / reception signals and attenuates the second and third harmonics, and the second filter 7 passes the EGSM transmission / reception signals and passes the third harmonics. It plays a role to attenuate.
[0006]
[Problems to be solved by the invention]
Since the composite high-frequency component 20 is mounted on a communication device such as a mobile phone, downsizing is required. At the same time, higher performance of composite high-frequency components for improving communication quality is also required.
[0007]
A conventional composite high-frequency component 20 including a diode switch composed of a diode, a capacitor, an inductor, and the like, a diplexer composed of a coil and a capacitor, and a filter is composed of a large number of components (elements), and is very complicated. It has a circuit configuration. In particular, chip components that cannot be formed inside the multilayer substrate such as diodes are mounted on the multilayer substrate, which hinders the miniaturization of the composite high-frequency component. In addition, since a large number of components (elements) are composed of complicated circuits, circuit wiring for connecting the components (elements) to each other is complicatedly routed across a plurality of substrates in the multilayer substrate. In order to connect components (elements) arranged on different boards, vias are usually provided on the boards for connection. As a result, the circuit wiring becomes longer, which may cause an increase in transmission loss and generation of noise due to coupling between circuit wirings.
[0008]
For example, in the multiband high-frequency switch module disclosed in Japanese Patent Application Laid-Open No. 2000-49651, a switch for switching between transmission and reception in a communication system is composed of a diode, a transmission line, and a capacitor. Similarly, connections such as capacitors formed on the transmission line or another substrate are also connected through vias. As a result, the thickness of the multilayer substrate becomes large, and it may be difficult to reduce the height.
[0009]
Accordingly, an object of the present invention is to simplify the circuit by reducing the number of components (elements) constituting the circuit, and to reduce the size of the composite high-frequency component, in particular, to reduce the height and increase the performance, and It is to provide a composite high-frequency component and a communication device that realize this.
[0010]
[Means, actions and effects for solving the problems]
The composite high frequency component of the present invention has a multilayer substrate formed by laminating a plurality of dielectric substrates, and each of an antenna and a transmission circuit or a reception circuit of each of the first communication system, the second communication system, and the third communication system. a composite high frequency component for switching the connection between, the first being connected to the first common terminal and the transmission unit terminal of the common transmission terminal unit and the third communication system of the first and second communication systems connected to the antenna terminal 1 input terminal, a first output terminal connected to the receiver terminal of the third communication system, a second output terminal connected to the receiver terminal of the second communication system, and a receiver terminal of the first communication system A third output terminal connected to the first output terminal, and any one of the first input terminal, the first output terminal, the second output terminal, and the third output terminal is a first output terminal, It is switched for connection to a common terminal Wherein includes a switch unit constituted by the GaAs semiconductor switching element and a capacitor are mounted on the multilayer substrate, the first filter terminal and a second filter terminal connected to said first input terminal, said Connected to a low-pass filter composed of capacitors and inductors formed inside the multilayer substrate, a second common terminal connected to the second filter terminal, and a common transmitter terminal of the first and second communication systems. A diplexer comprising a capacitor and an inductor formed inside the multilayer substrate, the second input terminal being connected to the transmitter terminal of the third communication system, and a third input terminal connected to the transmitter terminal of the third communication system. It is characterized by becoming.
[0014]
In the composite high frequency component of the present invention, a surface acoustic wave filter mounted on a multilayer substrate is connected to each of the first output terminal and the second output terminal.
In the composite high frequency component of the present invention, the surface acoustic wave filter is mounted on a surface on which the switch element is not mounted.
[0015]
Furthermore, the composite high frequency component of the present invention is characterized in that a capacitor constituting the switch section is mounted as a chip component on a multilayer substrate.
[0017]
The communication apparatus of the present invention is characterized by using the composite high frequency component.
[0019]
In the composite high-frequency component of the present invention , a circuit including an inductor and a capacitor for removing noise is connected to the first common terminal, and the inductor and the capacitor are formed inside the multilayer substrate or the substrate surface It may be formed by mounting chip parts.
[0020]
With the above configuration, the composite high-frequency component of the present invention can reduce the number of components (elements) constituting the circuit, thereby simplifying the circuit configuration. In addition, since a transmission line of a component (element) constituting a switch unit for switching transmission / reception formed over a plurality of substrates can be omitted, a multilayer substrate can be formed thinly, and the composite high frequency component as a whole It is possible to reduce the size and height. Furthermore, since the length of the wiring for connecting the components (elements) constituting the circuit is shortened, an increase in transmission loss can be suppressed, and the generation of noise due to the coupling between the wirings can be prevented.
[0021]
In addition, the composite high-frequency component of the present invention is applied to the first communication system and the second communication system in which the frequency bands to be used are close to each other, and the third communication system in which the frequency band to be used is separated from the first and second communication systems. It becomes possible to respond.
[0022]
The composite high-frequency component of the present invention includes a first diplexer, a switch unit including at least a switch element, and a filter circuit integrated with a multilayer substrate, and a switch element including a GaAs semiconductor element is mounted on the multilayer substrate. By forming the first diplexer and the filter circuit inside the multilayer substrate, the composite high frequency component can be miniaturized. Furthermore, the same effect can be obtained when a circuit for noise removal is also integrated with the multilayer substrate.
[0023]
Further, the composite high frequency component of the present invention uses a GaAs semiconductor element for the switch unit, so that the number of components (elements) constituting the switch unit for switching transmission / reception of a plurality of communication systems can be reduced. Therefore, the high frequency circuit is simplified. In addition, since the number of components (elements) mounted on the multilayer substrate is small, the composite high frequency component can be miniaturized. Furthermore, workability of component mounting is improved by reducing the number of components mounted on the multilayer substrate.
[0024]
In the composite high frequency component of the present invention, a low pass filter is connected between the switch unit and the diplexer, thereby connecting between the diplexer and the EGSM transmission terminals TX1 and DCS and the PCS common transmission unit terminal TX2. However, the number of low-pass filters can be reduced. That is, the harmonics of the transmission signal can be removed without increasing the number of components (elements).
[0025]
The capacitor constituting the switch part of the composite high frequency component of the present invention has a function of a capacitor for cutting direct current. Usually, a capacitor for cutting direct current is used with a large capacity. However, when the inner layer is formed on a multilayer substrate, the electrode area of the capacitor electrode must be increased or the capacitor electrode must be formed over a plurality of layers. Therefore, there is a case where miniaturization of the multilayer substrate is hindered. However, the composite high-frequency component according to the present invention enables the miniaturization of the multilayer substrate and the composite high-frequency component in order to mount the capacitor constituting the switch unit on the multilayer substrate.
[0026]
Further, the communication device of the present invention also exhibits the same effect by using the composite high frequency component of the present invention.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
A composite high frequency component 201 according to one embodiment of the present invention has a configuration as shown in FIG.
[0028]
2 and 3, a first diplexer 21 (not shown) formed in a multilayer substrate 101 having a dielectric substrate such as glass ceramic as an insulating layer and a conductive layer mainly composed of Ag or an Ag alloy, The filter 61 includes a switch unit 31 including a GaAs semiconductor element 315 and capacitors 316, 317, 318, 319, and 320 mounted on a multilayer substrate. The multilayer substrate 101 has a substantially rectangular parallelepiped shape, and a plurality of castellations 401 each having a semicylindrical concave portion on the lower side and a conductor layer on the inner side surface are formed on the four side surfaces. The composite high frequency component 201 can be mounted and connected on another substrate by the castellation 401. The castellation 401 corresponds to an antenna terminal in a high-frequency circuit, a transmission / reception unit terminal of each communication system, a control terminal, a ground terminal, and the like.
[0029]
The first communication system and the second communication system in which the frequency bands to be used formed in the composite high-frequency component 201 of the present invention are close to each other, and the third communication in which the frequency bands to be used are separated from the first and second communication systems. A high-frequency circuit 9 used in a triple-band mobile phone corresponding to the system will be described with reference to FIGS. FIG. 3 is a block diagram, and FIG. 4 is a circuit diagram. In this embodiment, the first communication system is a PCS of a TDMA communication system, a TDMA DCS is a second communication system, and a TDMA EGSM is a third communication system.
[0030]
3 and 4, the high-frequency circuit 9 is connected to the antenna terminal ANT and switches between the transmission signal and the reception signal of each communication system, and the diplexer 21 connected to the transmission unit of the communication system of EGSM, DCS, and PCS. And a low pass filter 61 for attenuating the second harmonic and the third harmonic in the transmission signal from the transmission unit from the communication system of EGSM, DCS, and PCS. The switch unit 31 is connected to the first common terminal 314 connected to the antenna terminal ANT, the first input terminal 311 connected to the first filter terminal 611 of the low-pass filter, and the reception unit terminal RX3 of the PCS. It has a third output terminal 312, a first output terminal 313 connected to the receiver section RX1 of EGSM, and a second output terminal 321 connected to the receiver section RX2 of DCS.
The switch unit 31 includes a switch element 315 including a GaAs semiconductor element and capacitors 316, 317, 318, 319, and 320. The switch element includes a first control terminal VC1 that controls connection / disconnection of the first common terminal and the first input terminal, and a second control that controls connection / disconnection of the first common terminal and the third output terminal. Terminal VC2, third control terminal VC3 for controlling connection / disconnection of the first common terminal and the first output terminal, and fourth control for controlling connection / disconnection of the first common terminal and the second output terminal A terminal VC4 is provided. Here, the capacitors 316, 317, 318, 319, and 320 have a function for cutting a direct current from the control terminals VC1, VC2, VC3, and VC4, and those having a capacity of about 30 pF or more are used. There are many cases.
[0032]
The diplexer 21 is connected to the second common terminal 211 connected to the second filter terminal 612 of the low-pass filter 61, the DCS, the second input terminal 212 connected to the PCS common transmitter terminal TX2, and the transmitter terminal TX1 of the EGSM. And a third input terminal 213 to be connected. In addition, the diplexer 21 has a function of a high-pass filter that allows a transmission signal from the DCS / PCS common transmission unit terminal TX2 to pass between the second common terminal 211 and the second input terminal 212, and the second common terminal 211. And a third input terminal 213 are provided with a function of a low-pass filter that allows a transmission signal from the transmission unit terminal TX1 of EGSM to pass therethrough.
[0033]
The diplexer 21 includes a low-pass filter composed of capacitors 121 and 122 and an inductance 123 and a high-pass filter composed of capacitors 127, 128 and 129 and an inductance 130.
[0034]
The diplexer 21 described above is a combination of a low-pass filter and a high-pass filter, but is not limited to this, and any combination of a low-pass filter, a high-pass filter, a notch filter, a band-pass filter, etc. other than this combination is possible. A diplexer may be used.
[0035]
The low pass filter 61 is connected between the first input terminal 311 of the switch unit 31 and the second common terminal 211 of the diplexer 21. The low-pass filter 61 includes capacitors 136, 137, 138, 139, and 140 and inductances 141 and 142, and is configured by a two-stage low-pass filter.
[0036]
The high-frequency circuit 9 of the present invention having such a configuration operates as follows when transmitting or receiving each communication system. The EGSM transmission signal is input from the EGSM transmission unit terminal TX1 to the second input terminal 213 of the diplexer 21, passes through a low-pass filter constituting the diplexer 21, and is a second common terminal of the first diplexer 21. 211, input to the first input terminal 311 of the switch unit 31 via the low-pass filter 61, and output from the first common terminal 314 of the switch unit 31. At this time, a signal is transmitted so as to connect the first common terminal 314 and the first input terminal 311 to the first control terminal VC1 of the switch element 315, and the second, third, and fourth control terminals VC2, A DC voltage is applied to VC3 and VC4 so that the third output terminal, the first output terminal, and the second output terminal are disconnected. On the other hand, an EGSM reception signal is input from the first common terminal 314 of the switch unit 31, output from the first output terminal 313, and sent to the EGSM reception unit terminal RX 1. At this time, a DC voltage is applied so as to connect the first common terminal 314 and the first output terminal 313 to the third control terminal VC3 of the switch element 315, and the first control terminal VC1 and the second control terminal VC2 A DC voltage is applied to the fourth control terminal VC4 so that the first input terminal 311, the third output terminal 312 and the second output terminal are disconnected.
[0037]
The DCS transmission signal is input from the DCS / PCS common transmitter terminal TX2 to the third input terminal 212 of the diplexer 21, passes through the high-pass filter that constitutes the first diplexer 21, and the second of the diplexer 21 has. Are output to the common terminal 211, pass through the low-pass filter 61, input to the first input terminal 311 of the switch unit 31, and output from the first common terminal 314 of the switch unit 31. At this time, a DC voltage is applied to the first control terminal VC1 of the switch element 315 so as to connect the first common terminal 314 and the first input terminal 311, and the second, third, and fourth control terminals VC2 are applied. , VC3 and VC4 are applied with a DC voltage so as to disconnect the third output terminal, the first output terminal and the second output terminal. On the other hand, a DCS reception signal is input from the first common terminal 314 of the switch unit 31 and output from the second output terminal 321. The output DCS reception signal is sent to the DCS reception unit terminal RX2. At this time, a DC voltage is applied so as to connect the first common terminal 314 and the second output terminal 321 to the fourth control terminal VC4 of the switch element 315, and the first control terminal VC1 and the second control terminal VC2 are connected. A DC voltage is applied to the third control terminal VC3 so that the first input terminal 311 and the third output terminal 312 are disconnected from the first output terminal.
[0038]
The PCS transmission signal is the same as in the case of DCS transmission. On the other hand, the PCS reception signal is input from the first common terminal 314 of the switch unit 31 and output from the third output terminal 312. The output PCS reception signal is sent to the PCS reception unit terminal RX3. At this time, a DC voltage is applied to the first control terminal VC2 of the switch element 315 so as to connect the first common terminal 314 and the third output terminal 312 as in the transmission, and the first and third control are performed. A DC voltage is applied from the terminals VC1, VC3, and VC4 so that the first input terminal 311, the first output terminal 313, and the second output terminal 321 are disconnected.
[0039]
In the case of an EGSM / DCS / PCS triple-band mobile phone, an EGSM transmission signal is 880 MHz to 915 MHz, a reception signal is 925 MHz to 960 MHz, a DCS transmission signal is 1710 MHz to 1785 MHz, a reception signal is 1805 MHz to 1880 MHz, PCS The transmission signal is 1850 MHz to 1910 MHz, and the reception signal is 1930 MHz to 1990 MHz. Therefore, the switch element 315 uses a GaAs MMIC made of a GaAs semiconductor having a frequency band of about 1000 MHz to 2000 MHz. In addition, since transmission / reception switching of each communication system can be performed only by using GaAsMMIC, the number of components (elements) constituting the high-frequency circuit is reduced, and the composite high-frequency component can be downsized. Since GaAs MMIC is configured as a chip component, it is mounted on a multilayer substrate when used for a composite high-frequency component. Further, the connection between each terminal of the GaAs MMIC and the parts (elements) such as the first and second diplexers and the low-pass filter is connected to a diplexer and a low-pass filter formed in the multilayer substrate through electrode pads (not shown).
[0040]
On the other hand, since GaAsMMIC is a device that is very susceptible to static electricity, an antistatic circuit may be added to the high-frequency circuit. Specifically, a circuit including a capacitor and an inductance is provided between the antenna terminal and the first common electrode of the switch unit 31. Capacitors and inductors may be mounted and formed as chip components on the multilayer substrate. However, if the antistatic circuit is also formed in the multilayer substrate, the size of the composite high-frequency component can be maintained.
[0041]
In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. For example, a surface acoustic wave filter (SAW filter) may be connected to each of the first output terminal and the second output terminal. When a high-frequency circuit to which a SAW filter is added is used for a composite high-frequency component, the SAW filter is mounted on a multilayer substrate. You may mount a SAW filter in the recessed part provided in the multilayer substrate. The recess may be formed on the surface on which the GaAs MMIC chip element is mounted. However, if the recess is formed on the bottom surface of the multilayer substrate on which the GaAs MMIC chip element is not mounted, the multilayer substrate is reduced in size in plan view. Therefore, it is preferable.
[Brief description of the drawings]
FIG. 1 is a block diagram of a triple-band high-frequency circuit used in a conventional triple-band mobile phone.
FIG. 2 is a perspective view of a composite high-frequency component that is one embodiment of the present invention.
FIG. 3 is a block diagram of a high frequency circuit according to an embodiment of the present invention.
FIG. 4 is a high-frequency circuit diagram according to an embodiment of the present invention.
[Explanation of symbols]
9 High-frequency circuit 311 1st input terminal 312 3rd output terminal 313 1st output terminal 314 1st common terminal 31 Switch part 315 Switch element 316-320 Capacitor 21 1st diplexer 22 2nd diplexer 211 2nd Common terminal 212 second input terminal 213 third input terminal 61 low pass filter 201 composite high frequency component 101 multilayer board
;

Claims (5)

Ri na have a multilayer substrate formed by laminating a plurality of dielectric substrate, an antenna and a first communication system, the composite high frequency for switching the connection between each of the transmitting circuit or the receiving circuit of the second communication system and third communication system Parts,
The first common terminal connected to the antenna terminal, the common transmission terminal portion of the first and second communication systems, and the first input terminal connected to the transmission portion terminal of the third communication system and the reception portion of the third communication system A first output terminal connected to the terminal, a second output terminal connected to the receiver terminal of the second communication system, and a third output terminal connected to the receiver terminal of the first communication system. and said first input terminal, said first output terminal, one of terminals of said second output terminal and the third output terminal, is switched for connection to the first common terminal, the multi-layer board a switch unit that consists in a GaAs semiconductor switching element and a capacitor are mounted on,
A low-pass filter having a first filter terminal and a second filter terminal connected to the first input terminal, and comprising a capacitor and an inductor formed inside the multilayer substrate;
The second common terminal connected to the second filter terminal, the second input terminal connected to the common transmitter terminal of the first and second communication systems, and the transmitter terminal of the third communication system. have a third input terminal, a composite high-frequency component and wherein the ing from the composed diplexer with a capacitor and an inductor that are formed inside the multilayer substrate. 2. The composite high frequency component according to claim 1 , wherein the capacitor constituting the switch unit is mounted as a chip component on the multilayer substrate. 3. The composite high frequency component according to claim 1, wherein a surface acoustic wave filter mounted on a multilayer substrate is connected to each of the first output terminal and the second output terminal. The composite high frequency component according to claim 3, wherein the surface acoustic wave filter is mounted on a surface on which the switch element is not mounted. A communication apparatus using the composite high-frequency component according to any one of claims 1 to 4 .