JP4143976B2 - module - Google Patents

Description

  The present invention relates to an RF circuit such as Bluetooth that is used in various computers, peripheral devices, mobile communication devices such as mobile phones, and uses a frequency hopping method in which data communication is performed by connecting them to each other. It relates to an integrated module.

The 2.4 GHz ISM (Industrial, Scientific and Medical, Industrial, Scientific and Medical) band is a radio that complies with IEEE 802.11 standards such as those for DSSS (Direct Sequence Spread Spectrum Direct Sequence Spread Spectrum) and wireless communications. It is used for LAN (WLAN) communication. Using the same 2.4 GHz ISM band as such wireless LAN (WLAN), connection with related electronic devices can be realized without using a cable, and this is a very convenient technology near field wireless standard Bluetooth. (Bluetooth ^™ ) has been proposed.
This Bluetooth uses the 2.4 GHz ISM frequency band divided into a plurality of radio channels, and further divides each radio channel into unit times (1/1600 seconds) to form time slots. A frequency hopping method with excellent noise resistance that is switched at each time slot is adopted. For switching between transmission and reception, a time division duplex (TDD) system is adopted in the same way as PHS (Personal Handy Phone System), and this TDD system is a system in which transmission and reception are the same carrier frequency.

Originally, the use of Bluetooth is assumed to be a relatively small area such as in the same premises and in the same building, so the area where radio waves reach is a distance range of about 10 m, 30 mW at the time of transmission, and 0. Designed to save power with 3mW. An example of such a Bluetooth RF circuit is shown in FIG. In this Bluetooth RF circuit, a high-frequency filter (FILTER) is disposed after the antenna ANT, and a high-frequency signal entering and radiating from the antenna is filtered into a transmission / reception signal to be transmitted. In the subsequent stage, a high-frequency switch SW for switching the connection between the transmission circuit TX and the antenna ANT and the connection between the reception circuit RX and the antenna ANT, and a balanced-unbalanced arrangement arranged between the high-frequency switch SW and the transmission circuit. A first balun transformer Balun1 which is a conversion circuit, and a second balun transformer Balun2 disposed between the high frequency switch and the receiving circuit are included.
As the high-frequency switch SW, a GaAs switch is widely used because Bluetooth communication is performed by the TDD system and power during transmission is extremely low, 30 mW. The switch circuit switches the connection between the antenna and the reception circuit and between the transmission circuit and the antenna, and the high frequency signal is appropriately guided to each circuit. The input / output unit on the switch circuit side of the RFIC is configured with two signal terminals so as to perform differential operations, respectively, so as to reduce the noise figure and increase the reception sensitivity. Since the input / output impedance of the RFIC is about 50Ω to 200Ω, an impedance conversion circuit is also required when the characteristic impedance of each component is different, and a balanced-unbalanced circuit is provided between the switch circuit and the RFIC. Balun transformers Balun 1 and 2 are arranged.

Such an RF circuit is required to be reduced in size and weight in accordance with market demands such as a reduction in size and weight of the equipment used for convenience of the wireless system, and there is a strong demand for lowering the price. The RFIC includes a high frequency device such as a power amplifier, and conventionally, a DC voltage is supplied from a DC voltage supply means via a choke coil to drive the RFIC. In response to the demand for reduction in size and weight, recent RF stage modules have been required to reduce circuit components including the choke coil.
In addition, devices using an RF circuit have been combined with mobile phones and the like. The ISM frequency band used by wireless LAN and Bluetooth is a band that has a lot of radiation noise from machine tools, microwave ovens, etc., so a frequency hopping method with excellent noise resistance was originally adopted as a wireless system. ing. However, when a high-frequency signal of a mobile phone such as a PCS (Personal Communication Services) or DCS (Digital Cellular System) is very close, the high-frequency signal acts as noise, and the frequency system Even so, it will be affected. On the other hand, Bluetooth high-frequency signals also act as noise for communication devices. For this reason, the high frequency signal out of the band radiated from the antenna is desired to be attenuated by 30 dB or more, for example, at a second harmonic in Bluetooth. However, when a GaAs switch is used as the switch circuit, a high-frequency filter disposed on the antenna top needs to have a large out-of-band attenuation because of the characteristics of a wide band insertion loss and a small out-of-band attenuation. However, in order to obtain a large out-of-band attenuation, it is necessary to increase the number of circuit elements constituting the filter, to deteriorate the insertion loss, to increase the shape, and to further reduce the size of the RF circuit. There was a limit to conversion.
Wireless LAN and Bluetooth are often used in devices that are driven by a battery, such as mobile phones and notebook computers. For this reason, further reduction in power consumption is desired, but it has been difficult for the above reasons. SUMMARY OF THE INVENTION An object of the present invention is to provide an RF circuit and a small RF stage module that have a reduced number of parts, excellent harmonic attenuation characteristics, and low power consumption.

A first aspect of the present invention is a module in which a filter and a balun transformer are formed on a laminate composed of an electrode pattern and a dielectric, wherein the filter is a bandpass filter composed of an inductor and a capacitor formed with the electrode pattern or This is a low-pass filter, and the balun transformer is a balanced-unbalanced conversion circuit. The filter is connected in series to the unbalanced end side without a switch circuit or power amplifier, and the power amplifier is connected to the balanced end side. The RFIC including the power amplifier is mounted on the laminate.
A second invention is a module in which a filter and a balun transformer are formed in a laminate composed of an electrode pattern and a dielectric, wherein the filter is a bandpass filter comprising an inductor and a capacitor formed by the electrode pattern or A low-pass filter, wherein the balun transformer is a balanced-unbalanced conversion circuit, and one end side of the filter is connected in series to the unbalanced end side without a switch circuit or a power amplifier, and the other end side of the filter A switch circuit is connected to the active body, and an active element of the switch circuit is mounted on the stacked body.
A third invention is a module in which a filter and a balun transformer are formed on a laminate comprising an electrode pattern and a dielectric, wherein the filter is formed by the electrode pattern, and the balun transformer is a balanced-unbalanced conversion circuit. The first transmission line includes a first transmission line, a second transmission line electromagnetically coupled to the first transmission line, and a third transmission line. One end of the first transmission line is connected to the unbalanced end. The other end is grounded or open, the second transmission line is grounded at one end, the other end is connected to the first balanced end, the third transmission line is grounded at one end, and the other end is second. One end of the second transmission line and the third transmission line are connected to a common ground capacitor, and the filter is connected in series to the unbalanced end side. It is a module. A DC voltage may be supplied from the hot side of the capacitor to the second and third transmission lines, and a DC voltage may be output from the first and second balanced terminals. In the module of the present invention, the RFIC power amplifier can be operated by this DC voltage.
The laminated body is preferably constructed by using a ceramic dielectric material that can be fired at a low temperature as a green sheet, a conductive paste on the green sheet, the transmission line and a capacitor as an electrode pattern, and laminating and firing them together.

The present invention will be described in detail below. FIG. 1 is an example of a circuit block of an RF circuit in which a module according to an embodiment of the present invention is used. FIGS. 2 to 5 are equivalent circuits of balun transformers Balun 1 and 2 used in the RF stage module.
This RF circuit includes a high-frequency filter (FILTER) that attenuates unnecessary high-frequency signals, a high-frequency switch (SW) that switches between a transmission signal and a reception signal, and balun transformers Balun1 and Balun2 as balanced-unbalanced conversion circuits.
FIG. 2 shows an example of a balun transformer used on the transmission side. The transmission-side (TX) balun transformer Balun1 includes a first transmission line L1, a second transmission line L2 and a third transmission line L3 that are electromagnetically coupled to the first transmission line L1, and the first transmission line L1. The transmission line L1 has one end connected to the unbalanced end 101 and the other end grounded. The second transmission line L2 has one end grounded and the other end connected to the first balanced end 102, and the third transmission line. One end of L3 is grounded and the other end is connected to the second balanced end 103. One ends of the first and second transmission lines of the balun transformer constituting the first balanced-unbalanced circuit are connected to each other and grounded via the capacitor C1, and from the hot side of the capacitor, A voltage supply terminal Vdd is formed in the second transmission line L2 and the third transmission line L3 so that a DC voltage can be supplied. When viewed from the voltage supply terminal Vdd, the second transmission line L2 and the third transmission line L3 have substantially the same line length, and when a DC voltage is supplied from the voltage supply terminal Vdd, The transmission line L2 and the third transmission line L3 have substantially the same current flowing in opposite directions, and substantially equal DC voltages are output to the first balanced end 102 and the second balanced end 103. . The first balanced end 102 and the second balanced end 103 are connected to an RFIC transmission side output unit, and when a DC voltage is applied from the voltage supply end Vdd, two balanced terminals of the RFIC transmission output unit In addition, substantially the same DC voltage can be applied simultaneously. For this reason, it is not necessary to prepare the choke coil which was conventionally required.
According to the RF circuit and module of the present invention, since a plurality of discrete components that have been conventionally required for voltage supply can be reduced, the RF stage module can be reduced in size and weight, and the price can be reduced. The capacitor C1 can also function to adjust the phase difference between the high-frequency signals input to the first balanced end 102 and the second balanced end 103.

FIG. 3 is an equivalent circuit showing another example of the balun transformer. In this balun transformer, one end of the first transmission line is connected to the unbalanced end and the other end is an open end, and the second transmission line The line has one end grounded and the other end connected to the first balanced end, and the third transmission line has one end grounded and the other end connected to the second balanced end. Also in this case, one ends of the first and second transmission lines of the balun transformer constituting the first balanced-unbalanced circuit are connected to each other and grounded via the capacitor C1, and from the hot side of the capacitor. A voltage supply terminal Vdd is formed so that a DC voltage can be supplied. Similar to the balun transformer disclosed in FIG. 2, the second transmission line L2 and the third transmission line L3 have substantially the same size. A current flows in the opposite direction, and a substantially equal DC voltage is output to the first balanced end 102 and the second balanced end 103. Therefore, there is no need to prepare a separate choke coil, and it is possible to reduce the number of discrete components that have been necessary for voltage supply in the past. Therefore, the RF circuit and module can be reduced in size and weight, and the price can be reduced. I can do it.
Further, this balun transformer has an attenuation pole in the second harmonic band of 2.4 GHz as shown in FIG. The balun transformer alone can attenuate unnecessary high-frequency signals, and the out-of-band attenuation required for the high-frequency filter arranged in the previous stage, especially the attenuation on the high-frequency side of the passband, does not need to be so large. Good. For this reason, since the high frequency filter can be configured with a small number of circuit elements, the size can be reduced, and the power consumption can be reduced because of the low insertion loss. When such a large amount of out-of-band attenuation is not required, a laminated LC filter and a surface acoustic wave filter can be used as the high-frequency filter, and both of them can be configured at low cost, and as a result, a module can also be provided at low cost. I can do it.

  An example of the balun transformer Balun2 used on the receiving side (RX) is shown in FIGS. For example, the balun transformer Balun2 of FIG. 4 includes a fourth transmission line L4, a fifth transmission line L5 that is electromagnetically coupled to the fourth transmission line L4, and a sixth transmission line L6. The line L4 has one end connected to the unbalanced end 105 and the other end grounded. The fifth transmission line L5 has one end grounded and the other end connected to the third balanced end 106, and the sixth transmission line. The line L6 has one end grounded and the other end connected to the fourth balanced end 107. One ends of the fifth and sixth transmission lines of the balun transformer constituting the first balanced-unbalanced circuit are connected to each other and grounded. The basic circuit configuration is the same as that of the balun transformer Balun 1 used on the transmission side (TX) except that it does not have the voltage supply terminal Vdd. The same applies to the balun transformer Balun2 shown in FIG.

  6 and 7 are equivalent circuits of the high-frequency switch (SW) constituting the RF circuit shown in FIG. For example, the diode switch shown in FIG. 6 includes diodes D1 and D2, transmission lines L10 and L11, and a capacitor C10 as main elements. Further, the GaAs switch shown in FIG. 7 includes field effect transistors FET1 to FET4, a capacitor C11, and resistors R1 and R2 as main elements. In these high-frequency switches, a DC cut capacitor is disposed as necessary.

  8 to 10 are equivalent circuits of a high frequency filter (FILTER) constituting the RF circuit shown in FIG. For example, the bandpass filter of FIG. 8 includes capacitors C100 to C106 and transmission lines L100 and L101 as main elements. Further, the low-pass filter shown in FIG. 9 includes capacitors C110 to C112 and a transmission line L110 as main elements. The low-pass filter shown in FIG. 10 includes capacitors C110 to C112 and transmission lines L110 and L111 as main elements. This low-pass filter has a transmission line L111 and a capacitor C112, and this series resonant circuit is connected to the ground. By appropriately selecting the inductor and capacitor C112 of the transmission line L111 of this series resonant circuit, the high frequency signal of other communication devices can be selectively attenuated. Further, since the series resonant circuit is not arranged in series in the signal path, the insertion loss characteristic of the high-frequency signal that should be passed through is not impaired.

  11 to 13 are circuit blocks showing other RF circuits. For example, an RF stage module shown as a circuit block in FIG. 11 uses a high-frequency filter (FILTER) disposed between an antenna (ANT) and a high-frequency switch (SW) as a low-pass filter, and the high-frequency switch SW and the receiving side (RX). A high-frequency filter (FILTER) is arranged between the balun transformer Balun 2 of the above. If comprised in this way, the insertion loss of the high frequency filter arrange | positioned between an antenna (ANT) and a high frequency switch (SW) will be compared with the case where the said high frequency filter is comprised only with a band pass filter, as shown in FIG. The insertion loss on the transmission side (TX) can be made smaller than that of the RF stage module shown in the circuit block of FIG. Further, the high-frequency filter (FILTER) disposed between the high-frequency switch SW and the receiving side (RX) balun transformer Balun2 is also made of the low-pass filter by the out-of-band attenuation required for the high-frequency filter, particularly from the pass band. However, the attenuation amount on the high frequency side may not be so large. For this reason, the high-frequency filter can be configured with a small number of circuit elements, so that it can be miniaturized and low power consumption can be realized. Further, as in the circuit block shown in FIG. 12, a high frequency filter (FILTER) may be arranged between the high frequency switch SW and the transmission side (TX) balun transformer Balun1, and this may be used as a low-pass filter. The insertion loss on the transmission side (TX) can be made smaller than the module shown in the circuit block of FIG. FIG. 13 shows an RF stage module configured as a receiving-side (RX) balanced-unbalanced conversion circuit using a surface acoustic wave filter having an input at the balanced end and an output at the balanced end. In this case, the balanced-unbalanced conversion circuit and the high-frequency filter can be constituted by a single surface acoustic wave filter, so that the RF stage module can be reduced in size.

  The band pass filter shown in FIG. 8 is arranged between the antenna and the high frequency switch, the diode switch shown in FIG. 6 is the high frequency switch, the transmission-side balanced-unbalanced conversion circuit is the balun transformer shown in FIG. The RF circuit shown in FIG. 1 is configured with the reception-side balanced-unbalanced conversion circuit as a balun transformer shown in FIG. In this RF circuit, a positive voltage is applied to the control terminal VC1 of the diode switch during transmission, the diodes D1 and D2 are turned on, and a DC voltage is applied from the voltage supply terminal Vdd of the balun transformer Balun1 on the transmission side. . Further, at the time of reception, a voltage of 0 is applied to the control terminal VC1 of the diode switch to turn off the diodes D1 and D2, and control is performed so that no DC voltage is applied to the voltage supply terminal Vdd of the balun transformer Balun1 on the transmission side. By controlling in this way, the RF stage module is made power-saving.

This RF circuit is used as a module, and the filter, switch circuit, balun transformer transmission line and capacitor are built in a laminate made of a dielectric, and passive elements, diodes, GaAsFETs, RFICs that could not be built in the laminate. The small RF stage module 200 shown in FIG. 15 was able to be configured by mounting the active elements such as those on the laminated body. The dielectric is, for example, a ceramic dielectric capable of low-temperature firing having a relative dielectric constant of 8 and containing Al ₂ O ₃ as a main component and SiO ₂ , SrO, CaO, PbO, Na ₂ O, and K ₂ O as subcomponents. The material is used to form a green sheet having a thickness of 30 μm to 200 μm by a known sheet forming method such as a doctor blade method, and a conductive paste such as Ag or Cu is printed on the green sheet, and then a high frequency filter or a balun transformer is used. In addition, the transmission line constituting the high-frequency switch, the electrode pattern constituting the capacitor and the ground electrode are formed, and these are appropriately laminated and integrally fired. Furthermore, it can be configured integrally by stacking a dielectric antenna on the multilayer body, or a surface mount type dielectric antenna may be mounted on the multilayer body. In addition, the laminated body may be formed by using HTCC (high temperature co-fired ceramic) technology, the dielectric may be Al ₂ O ₃ and the transmission line may be tungsten or molybdenum, or the circuit element may be mounted on the substrate. You can also

  As the module of the present invention, there are RF stage modules of various circuit blocks as described above.

  According to the present invention, it is possible to provide a small RF stage module with a reduced number of parts, excellent harmonic attenuation characteristics, and low power consumption.

1 is a circuit block diagram of an RF circuit according to an embodiment of the present invention. It is an equivalent circuit diagram which shows an example of the balun transformer used for the transmission side of the module of this invention. It is an equivalent circuit diagram which shows the other example of the balun transformer used for the transmission side of the module of this invention. It is an equivalent circuit diagram which shows an example of the balun transformer used for the receiving side of the module of this invention. It is an equivalent circuit diagram which shows the other example of the balun transformer used for the receiving side of the module of this invention. It is an equivalent circuit diagram which shows an example of the high frequency switch used for the module of this invention. It is an equivalent circuit diagram which shows the other example of the high frequency switch used for the module of this invention. It is an equivalent circuit diagram which shows an example of the high frequency filter used for the module of this invention. It is an equivalent circuit diagram which shows the other example of the high frequency filter used for the module of this invention. It is an equivalent circuit diagram which shows the other example of the high frequency filter used for the module of this invention. It is a circuit block diagram of the module which concerns on the other Example of this invention. It is a circuit block diagram of the module which concerns on the other Example of this invention. It is a circuit block diagram of the module which concerns on the other Example of this invention. It is a characteristic view which shows an example of the insertion loss characteristic of the balun transformer used for the module of this invention. It is a perspective view of the module concerning one example of the present invention.

Explanation of symbols

L1 First transmission line L2 Second transmission line L3 Third transmission line C1 Capacitor 101 Unbalanced end 102 First balanced end 103 Second balanced end Vdd Voltage supply end

Claims (4)

A module in which a filter and a balun transformer are formed in a laminate composed of an electrode pattern and a dielectric, wherein the filter is a band-pass filter or a low-pass filter composed of an inductor and a capacitor formed with the electrode pattern. The balun transformer is a balanced-unbalanced conversion circuit, wherein the filter is connected in series without passing through a switch circuit or a power amplifier on the unbalanced end side, and a power amplifier is connected on the balanced end side. A module comprising an RFIC including the laminate mounted on the laminate. A module in which a filter and a balun transformer are formed in a laminate composed of an electrode pattern and a dielectric, wherein the filter is a band-pass filter or a low-pass filter composed of an inductor and a capacitor formed with the electrode pattern. The balun transformer is a balanced-unbalanced conversion circuit. One end of the filter is connected in series to the unbalanced end without a switch circuit or a power amplifier, and a switch circuit is connected to the other end of the filter. A module comprising an active element of the switch circuit mounted on the laminate. A module in which a filter and a balun transformer are formed on a laminate composed of an electrode pattern and a dielectric, wherein the filter is formed by the electrode pattern, and the balun transformer is a balanced-unbalanced conversion circuit, Transmission line, a second transmission line electromagnetically coupled to the first transmission line, and a third transmission line. One end of the first transmission line is connected to the unbalanced end and the other end is grounded or The second transmission line is grounded at one end, the other end is connected to the first balanced end, the third transmission line is grounded at one end, and the other end is connected to the second balanced end, A module, wherein one end of the second transmission line and the third transmission line are connected to a common grounding capacitor, and the filter is connected in series to the unbalanced end side. The laminate is formed of a ceramic dielectric material that can be fired at a low temperature as a green sheet, a conductive paste on the green sheet, and the transmission line and capacitor as electrode patterns, which are laminated and integrally fired. The module according to any one of claims 1 to 3.

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