JP2009076993A - Front end module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front end module capable of making unnecessary a space for direct installation of an impedance matching circuit on a printed circuit board of a mobile device, attaining space saving, and reducing the manufacturing cost. <P>SOLUTION: Front end module 10 comprises a diplexer 20 connected to an antenna 40, first/second switch circuits 21 and 22 for switching a transmitted or received signal, transmitting side filter circuits 23 and 25, receiving side filter circuits 24 and 26, transmitting side impedance matching circuits 30 and 31 for adjusting impedance between a power amplifier 41 and the transmitting side filter circuits 23 and 25, and receiving side impedance matching circuits 32, 33 and 34 for adjusting impedance between the receiving side filter circuits 24 and 26 and a radio frequency circuit portion 42. All of the circuit components are configured in a multilayer substrate. Therefore, a space in which circuit components of each of impedance matching circuits 30-34 are to be mounted becomes unnecessary for a printed circuit board of mobile device. Accordingly, it is advantageous for miniaturization and reduction of parts count for the mobile device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a front-end module in which a high-frequency circuit between an antenna and a transmission circuit / reception circuit is mounted in a portable device.

  Since portable devices typified by cellular phones are strongly required to be downsized, a configuration in which a high-frequency circuit is integrated into a module is adopted. In recent years, portable devices that can share different frequency bands corresponding to a plurality of communication systems have become widespread, and the high-frequency circuit has become complex and multifunctional, so the importance of modularization has increased. In particular, a front-end module in which a front-end circuit is formed on a laminated (multilayer) substrate is generally used. Such a front-end module has a configuration in which a diplexer circuit, a switch circuit, a transmission-side filter circuit, and a reception-side filter circuit are each incorporated in a laminated substrate as a front-end circuit that performs a function between an antenna and a transmission circuit / reception circuit. Have. If a front end module is mounted on a printed circuit board of a portable device, the size of the substrate can be made much smaller than when individual circuit components are directly mounted on the substrate.

On the printed circuit board of the portable device described above, among the terminals formed on the front end module, in addition to connecting the antenna terminal to the antenna, the transmission terminal is connected to a transmission circuit such as a power amplifier, and the reception terminal is RFIC or the like. Connected to the receiving circuit. In general, at locations where different circuits are connected in a high-frequency circuit, signal loss and characteristic deterioration due to reflection occur due to impedance mismatch. Therefore, in order to prevent impedance mismatch, it is necessary to insert an impedance matching circuit (see, for example, Patent Document 1). Therefore, an impedance matching circuit using chip parts such as a coil and a capacitor is formed on the printed circuit board of the portable device, and one end thereof is connected to the front end module.
Japanese Patent Laid-Open No. 2006-237711

  Assuming a portable device capable of sharing a plurality of frequency bands as described above, it is necessary to configure a plurality of impedance matching circuits corresponding to the respective frequency bands between the front end module and the transmission circuit / reception circuit. Therefore, a large space for mounting circuit components used for the impedance matching circuit is required on the printed circuit board of the portable device. In particular, when the impedance matching circuit is composed of chip parts or the like, the number of parts increases and an extra space for wiring for connection is required, leading to an increase in the size of the entire printed circuit board. In addition, there is a concern about an increase in manufacturing cost due to an increase in the number of parts such as chip parts. Furthermore, when designing a portable device, a lot of man-hours are required to determine the circuit constant of the impedance matching circuit according to the characteristics of the printed circuit board.

  Therefore, the present invention has been made to solve these problems, and eliminates the need for a space for directly mounting an impedance matching circuit on a printed circuit board of a portable device having a front-end circuit. An object of the present invention is to provide a front-end module that can achieve a reduction in manufacturing cost.

  In order to solve the above problems, a first aspect of a front end module according to the present invention is a front end module in which a front end circuit connected between an external circuit including a receiving circuit and an antenna is formed on a multilayer substrate. And an impedance matching circuit for matching impedance between the front-end circuit and the receiving circuit, and circuit components constituting the impedance matching circuit are mounted on the multilayer substrate, and the impedance matching circuit is received by the receiving circuit. Terminals for connection to the circuit are formed.

  According to the first aspect of the front-end module of the present invention, the impedance matching circuit to be inserted between the front-end circuit and the receiving circuit in the signal path of the received signal received via the antenna includes the front-end module. Instead of being mounted on the printed circuit board to be mounted, it is mounted on a multilayer board constituting the front end module, and is connected to a receiving circuit via a terminal of the front end module. Therefore, the printed circuit board on which the front end module is mounted does not require a space for mounting circuit components constituting the impedance matching circuit, and the number of components can be reduced. In this case, the front-end module can be configured with a high density and is less affected by the routing of the wiring, and incorporating the impedance matching circuit is effective in reducing the size and cost of the portable device.

  In order to solve the above problem, a second aspect of the front end module of the present invention is a front end circuit in which a front end circuit connected between an external circuit including a transmission circuit and a reception circuit and an antenna is formed on a multilayer substrate. A first impedance matching circuit for matching an impedance between the front end circuit and the transmission circuit; and a second impedance matching circuit for matching an impedance between the front end circuit and the reception circuit. The multilayer substrate is mounted with circuit components respectively constituting the first impedance matching circuit and the second impedance matching circuit, and the first impedance matching circuit is connected to the transmission circuit. And receiving the first impedance matching circuit and the second impedance matching circuit. Second terminals are formed for connection to the circuit.

  According to the second aspect of the front-end module of the present invention, in addition to the second impedance matching circuit similar to the first aspect, the first impedance matching circuit to be inserted between the transmission circuit and the front-end circuit is a multilayer. It is mounted on the substrate and connected to the transmission circuit via the terminals of the front end module. Therefore, a space for mounting a larger number of circuit components is not required and the number of components can be reduced as compared with the circuit component of the first aspect, which is more effective in reducing the size and cost of the portable device.

  The present invention may be configured to include a switch circuit that switches a path of a transmission signal and a reception signal transmitted / received by the antenna using a switch element. In this case, in the second aspect, on the mounting surface of the multilayer substrate, the circuit component constituting the first impedance matching circuit and the circuit component constituting the second impedance matching circuit sandwich the switch element. You may mount so that it may become an opposing position.

  In the second aspect, the first terminal is formed on one side corresponding to the position of the first impedance matching circuit among the two opposing sides of the bottom surface of the second rectangular multi-layer substrate. The second terminal may be formed on the other side corresponding to the position of the second impedance matching circuit.

  In the second aspect, a transmission-side filter circuit inserted between the switch circuit and the first impedance matching circuit may be provided. Further, in the first and second aspects, the switch circuit and the A reception-side filter circuit inserted between the second impedance matching circuits may be provided.

  In the present invention, the front end circuit may share a plurality of different frequency bands. In the second aspect, a plurality of the transmission-side filter circuits and a plurality of the first impedance matching circuits corresponding to a plurality of frequency bands on the transmission side may be included. In the first and second aspects, A plurality of reception filter circuits and a plurality of (second) impedance matching circuits corresponding to a plurality of frequency bands on the reception side may be included.

  In the present invention, the (second) impedance matching circuit includes a dielectric layer under the dielectric layer on which the reception-side filter circuit is mounted, in a region immediately below a circuit component constituting the reception-side filter circuit. An inner layer may be formed as a conductor pattern.

  According to the present invention, the front end module is provided with the impedance matching circuit for matching the impedance between the external circuit and the front end circuit, and the circuit component is mounted on the multilayer substrate on which the front end circuit is configured. A space for configuring the impedance matching circuit on the printed circuit board on which the module is mounted becomes unnecessary. The front-end module can adopt a configuration that captures only the reception-side impedance matching circuit in addition to a configuration that captures the transmission-side / reception-side impedance matching circuit with the external transmission / reception circuit. On the printed circuit board on which the front-end module is mounted, the space for mounting a large number of circuit components can be reduced, and the number of components is reduced, so that the manufacturing cost can be reduced. Further, when designing the printed circuit board on which the front end module is mounted, it is not necessary to determine the constants of circuit components prior to mounting the impedance matching circuit, and the design man-hour can be reduced. As described above, according to the present invention, in a portable device having a front-end circuit, there is an effect in miniaturization and cost reduction due to space saving of the substrate.

  Embodiments of the present invention will be described with reference to the drawings. Below, two embodiment from which a structure differs is described about the case where this invention is applied with respect to the front end module mounted in the printed circuit board of portable apparatuses, such as a mobile telephone.

[First Embodiment]
FIG. 1 is a circuit block diagram of a front end module 10 according to a first embodiment of the present invention. The front-end module 10 according to the first embodiment is a module in which a high-frequency circuit including a front-end circuit is configured on a multilayer substrate (multilayer substrate). GSM (900 MHz band), DCS ( 1.8 GHz band) and PCS (1.9 GHz band) can be shared. As shown in FIG. 1, the front end module 10 according to the first embodiment includes a diplexer 20, a first switch circuit 21, a second switch circuit 22, transmission filter circuits 23 and 25, and a reception filter circuit 24. , 26, transmission-side impedance matching circuits 30, 31, and reception-side impedance matching circuits 32, 33, 34.

  The diplexer 20 is connected to an antenna 40 attached to the portable device, and distributes signals transmitted between the antenna 40 and the first switch circuit 21 or the second switch circuit 22. A signal corresponding to GSM is transmitted to the signal path on the first switch circuit 21 side, and a signal corresponding to DCS / PCS is transmitted to the signal path on the second switch circuit 22 side. The first switch circuit 21 switches the GSM signal path between the transmission signal and the reception signal, and the second switch circuit 22 switches the DCS / PCS signal path between the transmission signal and the reception signal. The circuit configuration of the diplexer 20, the first switch circuit 21, and the second switch circuit 22 will be described later.

  The transmission-side filter circuit 23 is a low-pass filter that passes GSM transmission signals, and the transmission-side filter circuit 25 is a low-pass filter that passes DCS / PCS transmission signals. As the transmission-side filter circuits 23 and 25, circuits in which capacitors and inductors are combined are used. The reception-side filter circuit 24 is a band-pass filter that passes a GSM reception signal, and the reception-side filter circuit 26 is a band-pass filter that passes a DCS / PCS reception signal. As the reception side filter circuits 24 and 26, narrow band SAW (Surface Acoustic Wave) filters are adopted, the reception side filter circuit 24 includes a GSM SAW filter, and the reception side filter circuit 26 is for DCS and PCS. Includes two SAW filters.

  The transmission side impedance matching circuit 30 is inserted between the GSM signal path of the power amplifier 41 that is a part of the transmission circuit and the transmission side filter circuit 23, and the transmission side impedance matching circuit 31 is connected to the DCS / of the power amplifier 41. It is inserted between the signal path of the PCS and the transmission side filter circuit 25. That is, when the impedance is mismatched between the power amplifier 41 and the transmission side filter circuits 23 and 25, signal loss due to reflection and deterioration of filter characteristics are caused. There is a role to align.

  The reception side impedance matching circuit 32 is inserted between the reception side filter circuit 24 and the GSM signal path of the RF circuit unit 42 which is a part of the reception circuit, and the reception side impedance matching circuits 33 and 34 are connected to the reception side. It is inserted between the filter circuit 26 and the DCS / PCS signal path of the RF circuit section 42. As will be described later, in the reception filter circuit 26, one reception impedance matching circuit 33 is connected to the DCS SAW filter, and the other reception impedance matching circuit 34 is connected to the PCS SAW filter. The role of these reception-side impedance matching circuits 32 to 34 is to match impedances at the respective connection locations as in the transmission side.

  Next, a specific circuit configuration of the front end module 10 of the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 shows a circuit configuration in a range including the diplexer 20, the first switch circuit 21, and the second switch circuit 22 in the overall configuration of FIG. 1. 3 is a circuit in a range including the transmission side filter circuits 23 and 25, the reception side filter circuits 24 and 26, the transmission side impedance matching circuits 30 and 31, and the reception side impedance matching circuits 32 to 34 in the overall configuration of FIG. The configuration is shown.

  As shown in FIG. 2, the diplexer 20 includes inductors L10 to L12 and capacitors C10 to C13. The port P10 of the diplexer 20 is connected to the antenna 40. An LC filter including inductors L10 and L11 and a capacitor C12 is formed on one side from the position of the port P10 so as to pass a signal in the GSM frequency band and sufficiently attenuate a signal in the DCS / PCS frequency band. Operate. In addition, an LC filter including an inductor L12 and capacitors C10, C11, and C13 is formed on the other side from the position of the port P10, and a signal in the DCS / PCS frequency band is passed, while a signal in the GSM frequency band is sufficiently passed. Operates to attenuate. Each node (connection point) sandwiching the two LC filters with respect to the port P10 is connected to the first switch circuit 21 and the second switch circuit 22, respectively.

  The first switch circuit 21 includes inductors L13 and L14, capacitors C14 to C16, diodes D10 and D11, and a resistor R10. In the first switch circuit 21, the port P 11 is connected to the transmission side filter circuit 23, and the port P 12 is connected to the reception side filter circuit 24. A series circuit of a diode D11 and a capacitor C16 is connected between the port P12 on the receiving side and the ground, and an intermediate node thereof is connected to the control voltage VC1 via a resistor R10. An LC filter including an inductor L14 and capacitors C14 and C15 is inserted between the port P12 on the reception side and the node on the diplexer 20 side. On the other hand, a diode D10 is connected in series between the port P11 on the transmission side and the node on the diplexer 20 side, and an inductor L13 is connected between the port P11 and the ground.

  Here, since both the diodes D10 and D11 are inserted so that the anode faces the control voltage VC1, the forward bias is applied when the control voltage VC1 is high, and the reverse bias is applied when the control voltage VC1 is low. . Therefore, when switching the first switch circuit 21 to the transmission side, the control voltage VC1 is controlled to be high so that the node on the diplexer 20 side is connected to the port P11 via the diode D10, and the port P12 is connected to the diode D11. And connected to the ground via a capacitor C16. On the other hand, when the first switch circuit 21 is switched to the reception side, the control voltage VC1 is controlled to be low so that the node on the diplexer 20 side is disconnected from the port P11 by the diode D10, and the port P12 is disconnected from the ground by the diode D11. Make it blocked.

  The second switch circuit 22 includes inductors L15 to L18, capacitors C17 to C21, diodes D12 and D13, and a resistor R11. In the second switch circuit 22, the transmission side port P 13 is connected to the transmission side filter circuit 25, and the port P 14 is connected to the reception side filter circuit 26. A series circuit of a diode D13 and a capacitor C20 is connected between one end of the receiving side port P14 across the capacitor C21 and the ground, and an intermediate node thereof is connected to the control voltage VC2 via a resistor R11. An LC filter composed of an inductor L17 and capacitors C18 and C19 and an LC filter composed of a capacitor C21 and an inductor L18 are inserted between the port P14 on the receiving side and the node on the diplexer 20 side.

  On the other hand, a diode D12 is connected in series between the port P13 on the transmission side and the node on the diplexer 20 side, and an LC filter including inductors L15 and L16 and a capacitor C17 is inserted. The series circuit of the capacitor C17 and the inductor L15 is connected in parallel with the diode D12, and the inductor L16 is connected between the intermediate node and the ground.

  Here, since both of the diodes D12 and D13 are inserted so that the anode faces the control voltage VC2, the forward bias is applied when the control voltage VC2 is high, and the reverse bias is applied when the control voltage VC2 is low. . Therefore, when switching the second switch circuit 22 to the transmission side, the control voltage VC2 is controlled to be high so that the node on the diplexer 20 side is connected to the port P13 via the diode D12, and the port P14 is connected to the diode D13. And are connected to the ground via capacitors C21 and C20. On the other hand, when the second switch circuit 22 is switched to the receiving side, the control voltage VC2 is controlled to be low so that the node on the diplexer 20 side is disconnected from the port P13 by the diode D12, and the port P14 is disconnected from the ground by the diode D13. Make it blocked.

  Next, as shown in FIG. 3, the transmission-side filter circuit 23 connected to the port P11 includes an inductor L30 and capacitors C30 to C32. Nodes at both ends of the parallel circuit including the inductor L30 and the capacitor C31 are connected to the ground via the capacitors C30 and C32. By appropriately setting the circuit constants of the transmission-side filter circuit 23, the GSM frequency band is allowed to pass, and an unnecessary high-frequency component is attenuated.

  The transmission filter circuit 25 connected to the port P13 includes inductors L31 and L32 and capacitors C33 to C37. Nodes at both ends of the first parallel circuit including the inductor L31 and the capacitor C34 are connected to the ground via the capacitors C33 and C35, and nodes at both ends of the second parallel circuit including the inductor L32 and the capacitor C36 are connected to the capacitor. It is connected to the ground via C35 and C37. Thus, since the transmission side filter circuit 25 is composed of two stages, a steep attenuation characteristic can be obtained. By appropriately setting the circuit constants of the transmission-side filter circuit 25, the DCS / PCS frequency band is allowed to pass and an unnecessary high-frequency component is attenuated.

  The reception-side filter circuit 24 connected to the port P12 is composed of one SAW filter 24a. The SAW filter 24a operates so as to pass only the GSM frequency band and attenuate the other low-frequency and high-frequency components. Since noise components are particularly problematic in the reception operation, the use of the SAW filter 24a can ensure a large attenuation and ensure good reception performance.

  The reception side filter circuit 26 connected to the port P14 includes two SAW filters 26a and 26b. The SAW filter 26a operates to pass only the DCS frequency band and attenuate the other low-frequency and high-frequency components. The SAW filter 26b operates to pass only the frequency band of the PCS and attenuate other low frequency and high frequency components. The DCS is 1.8 GHz band and the PCS is 1.9 GHz band, and both frequency bands are close to each other. However, if the SAW filters 26a and 26b are used, only the respective frequency bands can be selectively passed.

  Next, the transmission-side impedance matching circuit 30 connected to the transmission-side filter circuit 23 includes an inductor L40 and capacitors C40 and C41, and the port P15 is connected to the power amplifier 41. The transmission side impedance matching circuit 30 is inserted into the signal path of the GSM transmission signal TX1 transmitted from the power amplifier 41. The transmission-side impedance matching circuit 31 connected to the transmission-side filter circuit 25 includes an inductor L41 and capacitors C42 and C43, and the port P16 is connected to the power amplifier 41. The transmission-side impedance matching circuit 31 is inserted into the signal path of the DCS / PCS transmission signal TX2 transmitted from the power amplifier 41.

  The impedance is matched between the output side of the power amplifier 41 and the input side of each of the transmission side filter circuits 23 and 25 by appropriately setting the constants of the transmission side impedance matching circuits 30 and 31. That is, in the GSM frequency band, the input impedance of the transmission side filter circuit 23 and the output impedance of the power amplifier 41 are matched to a predetermined impedance, and the input of the transmission side filter circuit 25 is also in the DCS / PCS frequency band. The impedance and the output impedance of the power amplifier 41 are matched with a predetermined impedance.

  The reception-side impedance matching circuit 32 connected to the SAW filter 24a of the reception-side filter circuit 24 includes inductors L42 and L43 and capacitors C44 and C45, and a pair of ports P17a and P17b are connected to the RF circuit unit 42. A reception-side impedance matching circuit 32 is inserted into the signal path of the GSM reception signal RX1 transmitted to the RF circuit 42. The reception-side impedance matching circuit 33 connected to one SAW filter 26a of the reception-side filter circuit 26 includes inductors L44 and L45 and capacitors C46 and C47, and a pair of ports P18a and P18b are connected to the RF circuit unit 42. Is done. Furthermore, the reception side impedance matching circuit 34 connected to the other SAW filter 26b of the reception side filter circuit 26 includes inductors L46 and L47 and capacitors C48 and C49, and a pair of ports P19a and P19b are connected to the RF circuit unit 42. Is done. Of the reception signals transmitted to the RF circuit 42, the reception side impedance matching circuit 33 is inserted in the signal path of the DCS reception signal RX2, and the reception side impedance matching circuit 34 is inserted in the signal path of the PCS reception signal RX3. It is the composition which becomes.

  By appropriately setting the constants of the reception side impedance matching circuits 32 to 34, the impedance is matched between the output side of the reception side filter circuits 24 and 26 and the input side of the RF circuit unit 42. That is, the input impedances of the reception signals RX1, RX2, and RX3 of the RF circuit unit are the output impedance of the SAW filter 24a in the GSM frequency band, the output impedance of the SAW filter 26a in the DCS frequency band, and the SAW filter in the PCS frequency band. Each of the output impedances 26b is matched to a predetermined impedance. In the reception-side impedance matching circuits 32 to 34, the SAW filters 24a, 26a, and 26b are configured to output balanced signals, so that the reception signals RX1, RX2, and RX3 are transmitted via a pair of wires, respectively. Is done.

  Next, a structural example of the front end module 10 of the first embodiment will be described with reference to FIGS. 4 and 5. The front end module 10 having the front end circuit of FIG. 1 can be formed of a multilayer substrate using a ceramic dielectric material. 4 shows a component mounting diagram of the uppermost dielectric layer La, and FIG. 5 shows a terminal layout on the bottom surface of the lowermost dielectric layer Lb. Is shown.

  As shown in FIG. 4, circuit components used for the front end circuit of the front end module 10 are mounted on the surface of the dielectric layer La. On the surface of the dielectric layer La, the switch module 50, the SAW modules 51 and 52, the chip inductors constituting the inductors L40 to L47, and the chip capacitors constituting the capacitors C40 to 49 are mounted. In addition, ground patterns G are formed on both sides of the dielectric layer La. A metal cap (not shown) that covers the entire surface is attached to the top of the dielectric layer La.

  Here, since many of the inductors and capacitors shown in FIG. 2 or FIG. 3 can be formed using a conductor pattern, they are layered on a predetermined dielectric layer on the lower layer side. Of the circuit components constituting the front end circuit, a thick component needs to be mounted on the dielectric layer La. A predetermined number of dielectric layers are laminated between the uppermost dielectric layer La and the lowermost dielectric layer Lb to form conductor patterns and through holes corresponding to the circuit configurations of FIGS. The illustration is omitted. Note that the number of stacked layers of the entire stacked substrate can be freely set according to the overall circuit scale and characteristics.

  The switch module 50 is a chip component that incorporates main components of the first switch circuit 21 and the second switch circuit 22, and includes diodes D10 to D13 shown in FIG. The SAW module 51 is a chip component that incorporates the SAW filter 24 a of the reception-side filter circuit 24. The SAW module 52 is a chip component that incorporates the two SAW filters 26 a and 26 b of the reception-side filter circuit 26. As shown in FIG. 4, the switch module 50 and the SAW modules 51 and 52 are disposed near the center of the surface of the dielectric layer La.

  In one region (region in the upper part of the drawing) with respect to the position of the switch module 50, each chip inductor constituting the inductors L42 to L47 of the receiving side impedance matching circuits 32, 33 and 34 and capacitors C44 to C49 are constituted. Each chip capacitor is arranged. On the other hand, each of the chip inductors constituting the inductors L40 and L41 of the transmission side impedance matching circuits 30 and 31 and the capacitor C40 are arranged in a region (a region in the lower part of the drawing) facing the one region with the switch module 50 interposed therebetween. Each chip capacitor constituting C43 is arranged. As described above, the chip components constituting the reception-side impedance matching circuits 32 to 34 and the chip components constituting the transmission-side impedance matching circuits 30 and 31 are arranged at positions facing each other in the longitudinal direction of the multilayer substrate. The effect of such an arrangement will be described later.

  In the example of FIG. 4, the case where the chip components of the transmission side impedance matching circuits 30 and 31 and the reception side impedance matching circuits 32, 33, and 34 are mounted on the surface of the dielectric layer La has been described. May be formed as an inner layer as a conductor pattern of a dielectric layer below the dielectric layer La. For example, the inductors L42 to 47 and the capacitors C44 to C49 of the reception side impedance matching circuits 32 to 34 may be formed using a conductor pattern of a lower dielectric layer. With such a configuration, the size of the laminated substrate in the planar direction can be reduced. In this case, it is desirable that the conductor patterns corresponding to the reception-side impedance matching circuits 32 to 34 are formed in regions immediately below the SAW modules 51 and 52 of the dielectric layer La. As a result, the path length including a through hole connecting the SAW modules 51 and 52 and the reception-side impedance matching circuits 32 to 34 is shortened, and transmission loss can be reduced.

  Next, as shown in FIG. 5, terminals necessary for connecting the front end module 10 to the outside are formed on the bottom surface of the lowermost dielectric layer Lb. On the bottom surface of the dielectric layer Lb in FIG. 5, a number of ground terminals Tg connected to the ground, a terminal Ta connected to the antenna 40, terminals Tt1 and Tt2 connected to the power amplifier 41, and an RF circuit unit A pair of terminals Tr1, Tr2, Tr3 connected to 42, a power supply terminal Tv connected to the power supply, and control terminals Tc1, Tc2 connected to the control voltages VC1, VC2 are formed. A ground pattern G is formed in the central space of the dielectric layer Lb.

  In FIG. 5, the terminal Ta corresponds to the port P10 (FIG. 2), the terminals Tt1 and Tt2 correspond to the ports P15 and P16 (FIG. 3), respectively, and the terminals Tr1, Tr2 and Tr3 each have a pair of ports P17a and 17b. , Corresponding to the pair of ports P18a and 18b and the pair of ports P19a and P19b. Each terminal in FIG. 5 reflects the arrangement of the circuit components in FIG. 4 so that the transmission-side terminals Tt1 and Tt2 and the reception-side terminals Tr1, Tr2, and Tr3 face each other in the longitudinal direction of the multilayer substrate. ing.

  Such an arrangement facilitates the connection between the circuit components and the terminals on the transmission side and the reception side in the vertical direction of the multilayer board, and also for effective use of the printed circuit board space of the portable device. Is suitable. That is, when the front end module 10 is mounted, the power amplifier 41 is sandwiched between the power amplifier 41 adjacent to the terminals Tt1 and Tt2 and the RF circuit unit 42 adjacent to the terminals Tr1, Tr2, and Tr2. An efficient arrangement in which the front end module 10 and the RF circuit unit 42 are arranged in a row in this order can be realized.

  By the front end module 10 of the first embodiment described above, each impedance matching circuit 30 to 34 that has been conventionally mounted on the printed circuit board of the portable device is taken into the front end module 10 to save the printed circuit board of the portable device. Space can be realized. Here, in the entire front end module 10, the circuit scale increases by the amount of each impedance matching circuit 30 to 34, but the increase in space due to this can be minimized. That is, circuit components can be mounted at a high density on the front-end module 10 in which the high-frequency circuit is configured, and wiring can be less routed than a printed circuit board of a portable device. Further, when each of the impedance matching circuits 30 to 34 is mounted on a printed circuit board of a portable device, it is necessary to determine circuit constants at the time of designing, but the front end module 10 of the first embodiment is previously mounted. By adjusting the circuit constants to suit the portable device, the design man-hours for the portable device can be reduced.

[Second Embodiment]
FIG. 6 is a circuit block diagram of the front end module 11 according to the second embodiment of the present invention. As in the first embodiment, the front end module 11 of the second embodiment is configured to be able to share three communication systems of GSM, DCS, and PCS. As shown in FIG. 6, the front end module 11 of the second embodiment includes a diplexer 20, a first switch circuit 21, a second switch circuit 22, transmission side filter circuits 23 and 25, and a reception side filter circuit 24. , 26 and reception side impedance matching circuits 32, 33, 34. Therefore, the difference from the first embodiment is that the transmission-side impedance matching circuits 30 and 31 are not included in the front end module 11 and the transmission-side impedance matching circuits 43 and 44 are provided outside.

  Since the components included in FIG. 6 are the same as those in the first embodiment, the description thereof is omitted. In this case, the circuit configuration of FIG. 2 can be applied as it is to the second embodiment. Further, the circuit configuration of FIG. 3 can be similarly applied to the second embodiment except for the portions of the transmission side impedance matching circuits 30 and 31. Therefore, in the second embodiment, it is assumed that the port P15 is directly connected to the transmission filter circuit 23 and the port P16 is directly connected to the transmission filter circuit 25 in FIG.

  Next, a structural example of the front end module 11 of the second embodiment will be described with reference to FIGS. 7 and 8. The front end module 11 of the second embodiment can be formed of a multilayer substrate using a ceramic dielectric material, as in the case of the first embodiment. FIG. 7 shows a component mounting diagram of the uppermost dielectric layer Lc, and FIG. 8 shows a terminal layout on the bottom surface of the lowermost dielectric layer Ld.

  As shown in FIG. 7, circuit components used for the front-end circuit of the front-end module 11 are mounted on the surface of the dielectric layer Lc. On the surface of the dielectric layer Lc, the switch module 50, the SAW modules 51 and 52, the chip inductors constituting the inductors L42 to L47, and the chip capacitors constituting the capacitors C44 to 49 are mounted, and the ground pattern G is formed on both sides. Has been. Compared to FIG. 4 of the first embodiment, the difference is that the inductors L40 and L41 and the capacitors C40 to C43 are not mounted on the surface of the dielectric layer Lc. Other circuit components have the same shape and arrangement in FIGS.

  Next, as shown in FIG. 8, each terminal necessary for connecting the front end module 11 to the outside is formed on the bottom surface of the lowermost dielectric layer Ld. On the bottom surface of the dielectric layer Ld in FIG. 8, as in FIG. 5, a large number of ground terminals Tg, a terminal Ta connected to the antenna 40, terminals Tt1, Tt2 connected to the power amplifier 41, and an RF circuit unit A pair of terminals Tr1, Tr2, Tr3 connected to 42, a power supply terminal Tv connected to the power supply, and control terminals Tc1, Tc2 connected to the control voltages VC1, VC2 are formed. The roles of these terminals are the same as those of the first embodiment shown in FIG. 5, but the arrangement of the terminals in FIG. 8 is different from that shown in FIG. That is, as can be seen from FIG. 8, the transmission-side terminals Tt1 and Tt2 and the reception-side terminals Tr1, Tr2, and Tr3 are not arranged to face each other in the longitudinal direction of the multilayer substrate.

  Moreover, since the front end module 11 of the second embodiment has a small number of components mounted on the dielectric layer Lc, the size of the multilayer substrate in the planar direction is smaller than that of the first embodiment. Comparing FIG. 8 with FIG. 5, it can be seen that the size in the short direction is the same and the size in the long direction is slightly smaller. However, since it is necessary to provide the impedance matching circuits 43 and 44 on the printed circuit board of the portable device, a corresponding amount of space is required.

  In the front end module 11 of the second embodiment described above, as in the case of the first embodiment, it is possible to realize a space saving and a reduction in design man-hour of the portable device. However, in the second embodiment, only the reception-side impedance matching circuits 32 to 34 need to be taken into the front-end module 11 and the transmission-side impedance matching circuits 43 and 44 need to be mounted on the printed circuit board of the portable device. Therefore, the space secured on the printed circuit board of the portable device is smaller than that of the first embodiment, but the configuration of the front end module 11 is slightly simplified. Contrary to the second embodiment, a configuration may be adopted in which the impedance matching circuit on the transmission side is taken into the front end module 11 and the impedance matching circuit on the reception side is mounted on the printed board of the portable device.

  The contents of the present invention have been specifically described above based on the first and second embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Can be applied. For example, the functions and circuit configurations of the front-end circuits of the front-end modules 10 and 11 are examples, and the present invention can be widely applied even when a front-end circuit having various functions and circuit configurations is configured. . Further, in each of the above-described embodiments, the configuration in which three communication systems (GSM, DCS, PCS) having different frequency bands can be shared has been described. However, the front end that can support various combinations of one or a plurality of communication systems. The present invention can be widely applied to modules.

1 is a circuit block diagram of a front end module 10 of a first embodiment. FIG. 2 is a diagram illustrating a circuit configuration in a range including a diplexer 20, a first switch circuit 21, and a second switch circuit 22 in the entire configuration of FIG. 1 is a diagram showing a circuit configuration in a range including transmission side filter circuits 23 and 25, reception side filter circuits 24 and 26, transmission side impedance matching circuits 30 and 31, and reception side impedance matching circuits 32 to 34 in the overall configuration of FIG. is there. In the structural example of the front end module 10 of the first embodiment, it is a component mounting diagram of the uppermost dielectric layer La. FIG. In the structural example of the front end module 10 of the first embodiment, it is a terminal layout diagram of the bottom surface of the lowermost dielectric layer Lb. It is a circuit block diagram of the front end module 11 of 2nd Embodiment. In the structural example of the front end module 11 of the second embodiment, it is a component mounting diagram of the uppermost dielectric layer Lc. In the structural example of the front end module 11 of 2nd Embodiment, it is a terminal layout figure of the bottom face of the lowermost dielectric layer Ld.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Front end module 20 ... Diplexer 21 ... 1st switch circuit 22 ... 2nd switch circuit 23, 25 ... Transmission side filter circuit 24, 26 ... Reception side filter circuit 24a, 26a, 26b ... SAW filter 30, 31 ... Transmission side Impedance matching circuits 32, 33, 34... Reception impedance matching circuits L10 to L18, L30 to L32, L40 to L47... Inductors C10 to C21, C30 to C37, C40 to C49. P10 to P19b... Ports VC1, VC2... Control voltages Ta, Tg, Tt1, Tt2, Tr1, Tr2, Tr3, Tv, Tc1, Tc2.

Claims (10)

A front-end module in which a front-end circuit connected between an external circuit including a receiving circuit and an antenna is configured on a multilayer board,
An impedance matching circuit for matching impedance between the front end circuit and the receiving circuit;
A circuit component constituting the impedance matching circuit is mounted on the multilayer substrate, and a terminal for connecting the impedance matching circuit to the receiving circuit is formed.   The front end circuit includes a switch circuit that switches a path of a transmission signal and a reception signal that are transmitted and received by the antenna using a switch element, and a reception-side filter circuit that is inserted between the switch circuit and the impedance matching circuit. The front end module according to claim 1. The front-end circuit can share a plurality of different frequency bands, and includes a plurality of the reception-side filter circuits corresponding to a plurality of reception-side frequency bands,
3. The front end module according to claim 2, wherein the impedance matching circuit is a plurality of impedance matching circuits corresponding to a plurality of frequency bands on the receiving side.   The impedance matching circuit is formed as an inner layer as a conductor pattern in a region immediately below a circuit component constituting the reception-side filter circuit in a dielectric layer below the dielectric layer on which the reception-side filter circuit is mounted. The front end module according to claim 2 or 3. A front-end module in which a front-end circuit connected between an external circuit including a transmission circuit and a reception circuit and an antenna is configured on a multilayer board,
A first impedance matching circuit for matching impedance between the front end circuit and the transmission circuit;
A second impedance matching circuit for matching impedance between the front end circuit and the receiving circuit;
With
Circuit components constituting the first impedance matching circuit and the second impedance matching circuit are mounted on the multilayer substrate, and the first impedance matching circuit is connected to the transmission circuit. And a second terminal for connecting the first impedance matching circuit and the second impedance matching circuit to the receiving circuit. The front end circuit includes a switch circuit that switches a path of a transmission signal and a reception signal transmitted and received by the antenna by a switch element,
On the mounting surface of the multilayer substrate, the circuit components constituting the first impedance matching circuit and the circuit components constituting the second impedance matching circuit are mounted at opposing positions with the switch element interposed therebetween. The front end module according to claim 5.   Of the two opposing sides of the bottom surface of the rectangular multilayer substrate, the first terminal is formed on one side corresponding to the position of the first impedance matching circuit, and at the position of the second impedance matching circuit. The front end module according to claim 6, wherein the second terminal is formed on the corresponding other side.   In addition to the switch circuit, the front end circuit includes a transmission filter circuit inserted between the switch circuit and the first impedance matching circuit, and between the switch circuit and the second impedance matching circuit. The front-end module according to claim 6, further comprising: a reception-side filter circuit to be inserted. The front end circuit can share a plurality of different frequency bands, and a plurality of the transmission side filter circuits according to a plurality of frequency bands on the transmission side and a plurality of reception sides according to the plurality of frequency bands on the reception side Including a filter circuit,
The first impedance matching circuit is a plurality of first impedance matching circuits corresponding to a plurality of frequency bands on the transmitting side, and the second impedance matching circuit is a plurality of frequency bands on the receiving side. The front end module according to claim 8, wherein the front end module is a plurality of second impedance matching circuits corresponding to the first impedance matching circuit. The second impedance matching circuit is layered as a conductor pattern in a region immediately below a circuit component constituting the reception-side filter circuit in a dielectric layer below the dielectric layer on which the reception-side filter circuit is mounted. The front end module according to claim 8 or 9, characterized in that.

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