Circuit module

Isolators are disposed such that DC magnetic fields of permanent magnets intensity with each other, and thus, the input impedance of non-reciprocal circuits 3a and 3b (regulating means 3) is reduced. Accordingly, the impedance conversion ratio between the output impedance of amplifying means 2 and the input impedance of the regulating means 3 is reduced to be relatively small. Thus, by simplifying the configuration of matching means 4 disposed between the amplifying means 2 and the regulating means 3, the insertion loss of the matching means 4 can be reduced, thereby enhancing the efficiency of a circuit module 1. Additionally, it is possible to dispose the non-reciprocal circuits 3a and 3b close to each other so that the DC magnetic fields of the permanent magnets can intensity with each other, thereby increasing the design flexibility of the circuit module 1 and accordingly reducing the size of the circuit module 1.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a circuit module including amplifying means for amplifying multiple types of signals.

2. Description of the Related Art

These days, there is an increasing demand for multiband, multimode mobile communication terminals, such as cellular phones and mobile information terminals, which support multiple communication systems of different frequency bands or different modulation methods. Therefore, on a transmission side of this type of mobile communication terminal, a circuit module that supports multiple radio frequency signals of different frequency bands is mounted, as shown inFIG. 11(for example, see Patent Document 1). A circuit module500shown inFIG. 11is a module for amplifying radio frequency signals of multiple frequency bands (Bands), and includes a transmission route R1through which input signals RFin_BC0(800 MHz band) and RFin_BC3(900 MHz band) are amplified and are output as output signals RFout_BC0(800 MHz band) and RFout_BC3(900 MHz band) and a transmission route R2through which an input signal RFin_BC6(2 GHz band) is amplified and is output as an output signal RFout_BC6(2 GHz band).

In the transmission route R1, the input signals RFin_BC0and RFin_BC3input into a SAW filter501are switched by a switch502and are selectively input into an input terminal of a power amplifier503. Then, the input signals RFin_BC0and RFin_BC3amplified by the power amplifier503are input into a non-reciprocal circuit505, which is disposed subsequent to the power amplifier503, via a coupler504and are output to the exterior of the circuit module500via a switch506. Accordingly, the non-reciprocal circuit505prevents a signal reflected by, for example, an antenna element (not shown), disposed closer to the switch506from being output to the coupler504(power amplifier503). Part of the transmission signals RFin_BC0and RFin_BC3amplified by the power amplifier503is separated in the coupler504and is output to the exterior of the circuit module500as an output signal Coupler out.

In the transmission route R2, the transmission signal RFin_BC6input into a SAW filter507is input into an input terminal of a power amplifier508. Then, the input signal RFin_BC6amplified by the power amplifier508is input into a non-reciprocal circuit509, which is disposed subsequent to the power amplifier508, and is output to the exterior of the circuit module500. Accordingly, as in the above-described transmission route R1, the non-reciprocal circuit509prevents a signal reflected by, for example, an antenna element (not shown), disposed subsequent to the isolator509from being output to the power amplifier508. Part of the transmission signal RFin_BC6amplified by the power amplifier508is output to the exterior of the circuit module500as an output signal Coupler out via a capacitor510which is connected at one end between the power amplifier508and the non-reciprocal circuit509.Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-199602 (Paragraphs 0012 to 0023, FIGS. 1 and 2, and so on)

BRIEF SUMMARY OF THE INVENTION

In the above-described circuit module500, although they are not shown, matching circuits for matching the output impedance of the power amplifiers503and508to the input impedance of the non-reciprocal circuits505and509, respectively, are disposed between the power amplifier503and the non-reciprocal circuit505and between the power amplifier508and the non-reciprocal circuit509. However, the efficiency of the circuit module500is decreased by the insertion loss caused by the provision of the matching circuits. Accordingly, there is a demand for reducing the consumption of a current (increasing the efficiency) in the circuit module500by simplifying the configuration of the matching circuits. However, close examinations concerning this issue have not been conducted so far.

Additionally, the size of the non-reciprocal circuits505and509included in the above-described circuit module500is reduced by omitting the provision of a yoke for blocking a leakage of a DC magnetic field generated from a permanent magnet included in each of the non-reciprocal circuits505and509to the outside. Accordingly, in order to reduce the possibility that the characteristics of the non-reciprocal circuits505and509will be changed due to the inter-influence of DC magnetic fields of the permanent magnets included in the non-reciprocal circuits505and509, the non-reciprocal circuits505and509are separated from each other and are arranged such that the directions of the DC magnetic fields of the non-reciprocal circuits505and509are orthogonal to each other. Thus, in the above-described circuit module500, it is not possible to dispose the non-reciprocal circuits505and509close to each other, thereby reducing the design flexibility.

The present invention has been made in view of the above-described problems. It is an object of the present invention to provide a circuit module which can implement high efficiency by simplifying the configuration of matching means and which is reduced in size by disposing non-reciprocal circuits close to each other.

In order to achieve the above-described object, a circuit module of the present invention includes: amplifying means that amplifies a plurality of types of signals; regulating means that includes a plurality of non-reciprocal circuits individually disposed for the plurality of types of signals and that restricts a passing direction of each of the plurality of types of signals amplified by the amplifying means to one direction; and matching means that is disposed between the amplifying means and the regulating means and that matches output impedance of the amplifying means to input impedance of the regulating means. The plurality of non-reciprocal circuits include respective isolators. Each of the plurality of isolators includes a microwave magnetic body, a first center electrode and a second center electrode disposed on the microwave magnetic body such that the first and second center electrodes intersect with each other while being insulated from each other, and a permanent magnet that applies a direct-current magnetic field to a portion at which the first and second center electrodes intersect with each other. Among the plurality of isolators, at least two isolators are disposed such that the direct-current magnetic field of a permanent magnet of one isolator and the direct-current magnetic field of the permanent magnet of the other isolator intensify with each other.

According to the invention configured as described above, each of the isolators of the plurality of the non-reciprocal circuits included in the regulating means, which restricts the passing direction of each of signals amplified by the amplifying means for amplifying multiple types of signals to only one direction, includes a permanent magnet for applying a DC magnetic field to the intersecting portion of the first center electrode and the second center electrode which are disposed on the microwave magnetic body such that they intersect with each other while being insulated from each other. The isolators are disposed such that a DC magnetic field of the permanent magnet is intensified by a DC magnetic field of another permanent magnet. The DC magnetic field applied to each microwave magnetic body is intensified so as to decrease the permeability of the microwave magnetic body. Thus, the inductance of the first and second center electrodes disposed on each microwave magnetic body is reduced. Then, the input impedance of the isolators is also reduced.

Since the input impedance of the isolators is reduced, the input impedance of each of the non-reciprocal circuits (regulating means) can also be reduced, thereby relatively decreasing the impedance conversion ratio between the output impedance of the amplifying means and the input impedance of each of the non-reciprocal circuits. This makes it possible to simplify the configuration of the matching means, which is disposed between the amplifying means and the regulating means which matches the output impedance of the amplifying means to the input impedance of the regulating means (non-reciprocal circuits). Accordingly, since the matching means can be simplified, the insertion loss of the matching means can be reduced, thereby making it possible to enhance the efficiency of the circuit module.

Since the matching means can be simplified, it is possible to reduce the manufacturing cost of the circuit module. Moreover, unlike the related art, it is possible to dispose the non-reciprocal circuits close to each other so that the DC magnetic fields of the permanent magnets can intensify with each other. Accordingly, the design flexibility of the circuit module is increased, thereby making it possible to reduce the size of the circuit module.

Concerning each of the plurality of isolators, one end of the first center electrode may be connected to an input port of the isolator and the other end of the first center electrode may be connected to an output port of the isolator, and one end of the second center electrode may be connected to the input port of the isolator and the other end of the second center electrode may be connected to a ground port of the isolator. Each of the plurality of non-reciprocal circuits may include a capacitor circuit and a terminator circuit which are connected in parallel with an inductor constituted by the first center electrode of the associated isolator.

With this configuration, by setting the inductance of the second center electrode to be greater than the inductance of the first center electrode, when a radio frequency signal is input from an input terminal of a non-reciprocal circuit into an input port of an isolator, a current does not substantially flow into the second center electrode or a terminator, but flows into the first center electrode, and the radio frequency signal is output to an output terminal of the non-reciprocal circuit via an output port of the isolator.

On the other hand, when a radio frequency signal is input from the output terminal of the non-reciprocal circuit to the output port of the isolator, a current is attenuated by the terminator and a parallel resonance circuit constituted by the first center electrode and a capacitor. In this case, by setting the inductance of the second center electrode to be greater than the inductance of the first center electrode, the input impedance of the non-reciprocal circuit can be reduced. Accordingly, the impedance conversion ratio for converting the impedance of the output terminal of the amplifying means to the impedance of the input terminal of the non-reciprocal circuit (regulating means) can be reduced to be even smaller. This makes it possible to further simplify the configuration of the matching means and to further reduce the insertion loss of the matching means.

In order to convert the output impedance of the amplifying means to the predetermined output impedance (for example, 50Ω) of the non-reciprocal circuits (regulating means), two-step impedance conversion is implemented by making a change to the configuration of the matching means and by making a change to the configuration of the passive elements of the non-reciprocal circuits. It is thus possible to increase the design flexibility of the circuit module.

The amplifying means may include one power amplifier for amplifying the plurality of types of signals of different frequency bands, and the matching means may include a matching circuit having a filter function of outputting the plurality of types of signals amplified by the amplifying means to the associated non-reciprocal circuits.

With this configuration, it is not necessary to individually provide power amplifiers for transmission signals of different frequency bands, thereby simplifying the configuration of the amplifying means. It is thus possible to provide a simple, practical circuit module.

Concerning two of the non-reciprocal circuits in which isolators forming the plurality of non-reciprocal circuits are disposed adjacent to each other, the two non-reciprocal circuits may be disposed such that at least one magnetic pole of the permanent magnet of the isolator forming one of the non-reciprocal circuits is adjacent to a magnetic pole of the opposite polarity of the permanent magnet of the isolator forming the other one of the non-reciprocal circuits.

With this configuration, at least one magnetic pole of a permanent magnet of one non-reciprocal circuit is disposed adjacent to a magnetic pole of the opposite polarity of a permanent magnet of the other non-reciprocal circuit. As a result, it is possible to efficiently intensity DC magnetic fields of the permanent magnets.

In this case, the magnetic poles of two of the permanent magnets may be disposed such that they are aligned, or both of magnetic poles of one of the permanent magnets may be disposed adjacent to magnetic poles of the opposite polarities of the other one of the permanent magnets, or the isolators may be disposed such that a straight line passing through both of the magnetic poles of one of the permanent magnets intersects with a straight line passing through both of the magnetic poles of the other one of the permanent magnets.

By disposing the isolators in this manner, it is possible to reliably intensify the DC magnetic fields of the permanent magnets each other.

According to the present invention, isolators are disposed such that the DC magnetic fields of the permanent magnets intensity with each other, and thus, the input impedance of non-reciprocal circuits (regulating means) is reduced. Accordingly, the impedance conversion ratio between the output impedance of amplifying means and the input impedance of each of the non-reciprocal circuits is reduced to be relatively small. Thus, by simplifying the configuration of matching means disposed between the amplifying means and the regulating means, the insertion loss of the matching means can be reduced, thereby enhancing the efficiency of a circuit module. Additionally, it is possible to dispose the non-reciprocal circuits close to each other so that the DC magnetic fields of the permanent magnets can intensity with each other, thereby increasing the design flexibility of the circuit module and accordingly reducing the size of the circuit module.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

A first embodiment of a circuit module of the present invention will be described below with reference toFIGS. 1 through 5.FIG. 1is a block diagram illustrating the first embodiment of a circuit module of the present invention.FIG. 2is a circuit block diagram illustrating the configuration of a transmission route included in the circuit module shown inFIG. 1.FIG. 3is an exploded perspective view illustrating ferrite and magnetic elements forming an isolator of a non-reciprocal circuit.FIG. 4is a diagram illustrating a state in which the isolators are arranged.FIG. 5is a graph illustrating the impedance characteristics obtained when the isolators are arranged in the state shown inFIG. 4.

A circuit module1shown inFIG. 1is a power amplifier module which is formed by disposing amplifying means2, regulating means3, matching means4, and so on, on a substrate made of, for example, a resin or ceramics. The circuit module1is used in a transmission circuit of a mobile communication terminal (communication system), such as a cellular phone or a mobile information terminal. The amplifying means2includes power amplifiers2aand2bwhich individually amplify transmission signals (radio frequency signals) of different frequency bands input into input terminals PIa and PIb. The regulating means3includes a plurality of non-reciprocal circuits3aand3bwhich are individually disposed corresponding to transmission signals and restricts the passing direction of transmission signals amplified by the amplifying means2to only one direction. The matching means4is disposed between the amplifying means2and the regulating means3and includes matching circuits4aand4bwhich match the output impedance of the amplifying means2to the input impedance of the regulating means3. Transmission signals input into the input terminals PIa and PIb, amplified in the circuit module1, and output from output terminals POa and POb are output to an antenna element via a splitter circuit (not shown), such as a duplexer.

More specifically, the circuit module1is a multiband, multimode communication terminal device and includes a first transmission route Ra and a second transmission route Rb. The first transmission route Ra is used for all communications performed by using a first transmission frequency band, such as a transmission frequency band (1920 to 1980 MHz) of W-CDMA (Wideband Code Division Multiple Access) method Band 1, a transmission frequency band (1850 to 1910 MHz) of W-CDMA Band 2, a transmission frequency band (1710 to 1785 MHz) of W-CDMA Band 3, a transmission frequency band (1710 to 1785 MHz) of a GSM (Global System for Mobile Communications) (registered) 1800 method, and a transmission frequency band (1850 to 1910 MHz) of a GSM 1900 method, or such as a transmission frequency band (1920 to 1980 MHz) of LTE (Long Term Evolution)/W-CDMA method Band 1, a transmission frequency band (1850 to 1910 MHz) of LTE/W-CDMA Band 2, a transmission frequency band (1710 to 1785 MHz) of LTE/W-CDMA Band 3. The second transmission route Rb is used for all communications performed by using a second transmission frequency, such as a transmission frequency band (824 to 849 MHz) of W-CDMA Band 5, a transmission frequency band (880 to 915 MHz) of W-CDMA Band 8, a transmission frequency band (806 to 821 MHz and 824 to 849 MHz) of a GSM 800 method, and a transmission frequency band (870.4 to 915 MHz) of a GSM 900 method, or such as a transmission frequency band (824 to 849 MHz) of LTE/W-CDMA Band 5 and a transmission frequency band (880 to 915 MHz) of LTE/W-CDMA Band 8.

The configurations of the transmission routes Ra and Rb of the circuit module1will now be discussed in detail. The configurations of the transmission routes Ra and Rb are substantially the same, and thus, an explanation of the configuration of the second transmission route Rb will be omitted by explaining the configuration of the first transmission route Ra.

The power amplifier2aincludes an amplifier element20constituted by, for example, a HBT (heterojunction bipolar transistor) forming a common emitter. The amplifier element20, which is disposed at the output stage of the power amplifier2a, amplifies a transmission signal input into the input terminal PIa and outputs it from an output terminal P1. InFIG. 2, the amplifier element20disposed at the output stage of the power amplifier2ais only shown, and other amplifier elements forming the power amplifier2aand an interstage matching circuit disposed between amplifier elements are not shown for the sake of simple representation. Instead of a heterojunction bipolar transistor, a common-source field-effect transistor may be used as the amplifier element.

As shown inFIG. 2, in this embodiment, the output impedance of the power amplifier2is set to be about 5Ω.

The non-reciprocal circuit3ais constituted by an isolator30aand chip components, such as a chip capacitor, a chip coil, and a chip resistor. The chip components are mounted on a substrate and are used for determining the characteristics of the isolator30a. The isolator30aincludes microwave ferrite31(corresponding to a “magnetic body” of the present invention) having a pair of opposing principal surfaces and a pair of permanent magnets32. The ferrite31is disposed between one magnetic pole of one permanent magnet32and the other magnetic pole of the opposite polarity of the other permanent magnet32. More specifically, the ferrite31and the permanent magnets32are formed in a rectangular parallelepiped, and the ferrite31and the pair of permanent magnets32are bonded to each other by using, for example, an epoxy adhesive38, so that DC magnetic fields H of the permanent magnets32will be applied substantially perpendicularly to the principal surfaces of the ferrite31.

The ferrite31includes a first center electrode33(inductor L1) and a second center electrode34(inductor L2). One end of the first center electrode33is connected to an input port35and the other end thereof is connected to an output port36. One end of the second center electrode34is connected to the input port35and the other end thereof is connected to a ground port37in the state in which the second center electrode34is insulated from the first center electrode33on both principal surfaces of the ferrite31. The input port35, the output port36, and the ground port37are disposed on one of the side surfaces which are perpendicular to both principal surfaces of the ferrite31. DC magnetic fields H are applied from the permanent magnets32to a portion at which the first and second center electrodes33and34intersect with each other.

The first center electrode33is formed on the ferrite31and is constituted by a conductor film. The first center electrode33is raised from the bottom right portion of one principal surface of the ferrite31and branches off in two directions. In this state, the first center electrode33extends toward the top left portion of the ferrite31while being tilted at a comparatively small angle. Then, the first center electrode33is raised toward the top left portion and turns around and to the other principal surface of the ferrite31via a relay electrode disposed on the top surface. The first center electrode33is formed from the top left portion to the bottom right portion on the other principal surface such that it is substantially superposed on the first center electrode33formed on the opposing principal surface, as viewed from a direction perpendicularly passing through the two principal surfaces, and is then connected to the input port35.

The second center electrode34, which is constituted by a conductor film, is formed on the ferrite31in the state in which it is insulated from the first center electrode33on both principal surfaces of the ferrite31. The second center electrode34is formed such that it intersects with the first center electrode33while being tilted from the bottom right portion of one principal surface of the ferrite31toward a long side of the ferrite31at a comparatively large angle, turns around the ferrite31, and is then connected to the ground port37.

The ferrite31may be constituted by, for example, YIG ferrite, and the first and second center electrodes33and34and the ports35,36, and37may be formed as a silver or silver-alloy thick or thin film by using a printing, transfer, or photolithographic method. An insulating film for insulating the first and second center electrodes33and34from each other may be formed as a dielectric thick film made of, for example, glass or alumina, or a resin film made of, for example, polyimide, by using a printing, transfer, or photolithographic method.

The ferrite31may be fired integrally with the insulating film and various electrodes by using a magnetic material. In this case, the electrodes are suitably constituted by Pd, Ag, or an alloy thereof, which are resistant to high-temperature firing.

As the material for the permanent magnets32, any material, such as a strontium ferrite magnet or a lanthanum-cobalt ferrite magnet, may be used. The strontium ferrite magnet exhibits excellent magnetic characteristics, such as the residual magnetic flux density and the coercive force, and also exhibits high insulating properties (small loss characteristics) in a high-frequency band. The lanthanum-cobalt ferrite magnet exhibits excellent magnetic characteristics, such as the residual magnetic flux density and the coercive force, and is suitably used for reducing the size of the circuit module and is also sufficiently used in terms of insulating properties in a high-frequency band.

Between the input port35and the output port36of the isolator30a, a capacitor C1is connected in parallel with the inductor L1(first center electrode33) so as to form a resonance circuit constituted by the inductor L1and the capacitor C1. Between the input port35and the output port36of the isolator30a, an LC series resonance circuit5connected in series with a terminator R is connected in parallel with the resonance circuit (first center electrode33) constituted by the inductor L1and the capacitor C1. In this embodiment, the LC series resonance circuit5is constituted by an inductor L3and a capacitor C2connected in series with each other. However, the LC series resonance circuit5may be formed by interposing the inductor L3between two capacitors or by interposing the capacitor C2between two inductors.

Impedance adjusting capacitors CS1and CS2are connected to the input port35and the output port36, respectively, of the isolator30a.

In the non-reciprocal circuit3aconfigured as described above, the inductance of the inductor L2(second center electrode34) is set to be greater than the inductance of the inductor L1(first center electrode33). Accordingly, when a radio frequency signal is input from an input terminal P2of the non-reciprocal circuit3a, a current does not substantially flow into the inductor L2or the terminator R, but flows into the inductor L1, and the radio frequency signal is output from an output terminal P3of the non-reciprocal circuit3a. On the other hand, when a radio frequency signal is input from the output terminal P3of the non-reciprocal circuit3ain the reverse direction, a backward current is attenuated by the terminator R and the parallel resonance circuit constituted by the inductor L1and the capacitor C1.

In this case, by setting the inductance of the inductor L2to be greater than the inductance of the inductor L1, the input impedance of the non-reciprocal circuit3ais reduced to be about a half of the input impedance of a known non-reciprocal circuit in which both of the input impedance and the output impedance are set to be 50Ω. In this embodiment, the isolators30aare disposed such that DC magnetic fields of the permanent magnets32of the non-reciprocal circuits3aand3bintensify with each other, which will be discussed later, and thus, the impedance of the inductors L1and L2is reduced, and the input impedance of the non-reciprocal circuits3aand3bis set to be about 15Ω.

By suitably adjusting the state in which the first and second center electrodes33and34are wound around the ferrite31, for example, by suitably adjusting the intersecting angle of the first and second center electrodes33and34, electrical characteristics, such as the input impedance and the insertion loss, of the non-reciprocal circuit3are adjusted. That is, in accordance with an increase in the inductance ratio (L2/L1: the ratio of the second center electrode34to the first center electrode33wound around the ferrite31), both of the real part and the imaginary part of the input impedance of the non-reciprocal circuit3are increased. By suitably setting the numbers of turns of the first and second center electrodes33and34, the impedance conversion ratio for converting from the input impedance (15Ω) to the output impedance (about 50Ω) can be adjusted. The imaginary part of the impedance is adjusted from a certain value to 0 by the impedance adjusting capacitors CS1and CS2.

Between the input port35and the output port36of the non-reciprocal circuit3a, the LC series resonance circuit5connected in series with the terminator R is connected in parallel with the resonance circuit constituted by the inductor L1(first center electrode33) and the capacitor C1. Accordingly, when a radio frequency signal is input into the output terminal P3of the non-reciprocal circuit3ain the reverse direction, impedance matching is performed in a wide band by the impedance characteristics of the terminator R and the LC series resonance circuit5. Thus, over a wide frequency band, isolation characteristics of the non-reciprocal circuit3acan be improved and insertion loss of the non-reciprocal circuit3of the transmission module can be reduced.

As shown inFIG. 2, the matching circuit4ais formed as a single-stage low pass filter constituted by an inductor L11and a capacitor C11. In this embodiment, by the matching circuit4a, as shown inFIG. 2, the output impedance 5Ω of the power amplifier2ais converted into the input impedance 15Ω of the non-reciprocal circuit3a.

The arrangement states of the isolators30aand30bincluded in the non-reciprocal circuits3aand3b, respectively, will be discussed below.

The non-reciprocal circuits3aand3bare disposed such that at least one magnetic pole N of a permanent magnet32of one non-reciprocal circuit3a(isolator30a) is adjacent to a magnetic pole S, which is the opposite polarity of the magnetic pole N, of the other non-reciprocal circuit3b(isolator30b). That is, the isolators30aand30bare disposed such that a DC magnetic field H of a permanent magnet32of one isolator30aand a DC magnetic field H of a permanent magnet2of the other isolator30bintensify with each other more closely. More specifically, in this embodiment, as shown inFIG. 4, the magnetic poles N and S of a permanent magnet32of one isolator30aare disposed adjacent to the magnetic poles S and N, which are the opposite polarities of the magnetic poles N and S, respectively, of a permanent magnet32of the other isolator30b.

With this configuration, as shown inFIG. 5, as the distance x between the isolators30aand30bdecreases, the DC magnetic fields H intensify with each other more closely, and the input impedance of each of the non-reciprocal circuits3aand3bis reduced. InFIG. 5, the horizontal axis indicates the distance x between the isolators30aand30b, and the vertical axis indicates a variation in the input impedance of each of the non-reciprocal circuits.FIGS. 7 and 9, which will be referred to when discussing modified examples later, are indicated in a similar manner, and thus, an explanation thereof will be omitted.

First Modified Example

A first modified example of the arrangement state of the isolators will be discussed below with reference toFIGS. 6 and 7.FIG. 6is a diagram illustrating a first modified example of a state in which the isolators are arranged, andFIG. 7is a graph illustrating the impedance characteristics obtained when the isolators are arranged in the state shown inFIG. 6.

As shown inFIG. 6, in the first modified example, the magnetic poles N and S of the permanent magnets32of the isolators30aand30bare aligned so that the directions from the magnetic pole N to the magnetic pole S will be the same. According to this arrangement state of the isolators30aand30b, too, as shown inFIG. 7, as the distance x between the isolators30aand30bdecreases, the DC magnetic fields H intensify with each other more closely, and the input impedance of each of the non-reciprocal circuits3aand3bis reduced.

Second Modified Example

A second modified example of the arrangement state of the isolators will be discussed below with reference toFIGS. 8 and 9.FIG. 8is a diagram illustrating a second modified example of a state in which the isolators are arranged, andFIG. 9is a graph illustrating the impedance characteristics obtained when the isolators are arranged in the state shown inFIG. 8.

As shown inFIG. 8, in the second modified example, the isolators30aand30bare disposed such that a straight line perpendicularly passing through both magnetic poles of the permanent magnets32of one isolator30aintersects with a straight line perpendicularly passing through both magnetic poles of the permanent magnets32of the other isolator30b. According to this arrangement state of the isolators30aand30b, too, as shown inFIG. 9, as the distance x between the isolators30aand30bdecreases, the DC magnetic fields H intensify with each other more closely, and the input impedance of each of the non-reciprocal circuits3aand3bis reduced.

As described above, according to the above-described embodiment, each of the isolators30aand30bof the plurality of the non-reciprocal circuits3aand3b, respectively, included in the regulating means3, which restricts the passing direction of transmission signals amplified by the amplifying means2for amplifying multiple types of signals of different frequency bands to only one direction, includes permanent magnets32for applying DC magnetic fields H to the intersecting portion of the first center electrode33(inductor L1) and the second center electrode34(inductor L2) which are disposed on the microwave ferrite31such that they intersect with each other while being insulated from each other. The isolators30aand30bare disposed such that a DC magnetic field H of one permanent magnet32is intensified by a DC magnetic field H of another permanent magnet32. The DC magnetic field H applied to each ferrite31is intensified so as to decrease the permeability of the ferrite31. Thus, the inductance of the first and second center electrodes33and34disposed on each ferrite31is reduced. Then, the input impedance of the isolators30aand30bis also reduced.

Since the input impedance of the isolators30aand30bis reduced, the input impedance of each of the non-reciprocal circuits3aand3bcan also be reduced, thereby decreasing the impedance conversion ratio between the output impedance of the amplifying means2and the input impedance of each of the non-reciprocal circuits3aand3b. This makes it possible to simplify the configuration of the matching means4(matching circuits4aand4b), which is disposed between the amplifying means2and the regulating means3(non-reciprocal circuits3aand3b) and which matches the output impedance of the amplifying means2to the input impedance of each of the non-reciprocal circuits3aand3b. Accordingly, the insertion loss of the matching means4can be reduced, and thus, the power efficiency of the circuit module1can be enhanced.

Since the matching means4can be simplified, it is possible to constitute the matching means4by matching circuits4aand4b, each of which is a simple, practical, single-stage low pass filter constituted by an inductor L11and a capacitor C11, thereby reducing the manufacturing cost of the circuit module1. Moreover, unlike the related art, it is possible to dispose the non-reciprocal circuits3aand3bclose to each other so that the DC magnetic fields H of the permanent magnets32can intensify with each other. Accordingly, the design flexibility of the circuit module1is increased, thereby making it possible to reduce the size of the circuit module1.

By setting the inductance of the second center electrode34to be greater than the inductance of the first center electrode33, the input impedance of the non-reciprocal circuits3aand3bis reduced. Accordingly, the impedance conversion ratio for converting the impedance of the output terminal P1of the amplifying means2to the impedance of the input terminal P2of the non-reciprocal circuits3aand3b(regulating means3) can be reduced to be even smaller. This makes it possible to further simplify the configuration of the matching means4and to further reduce the insertion loss of the matching means4.

In order to convert the output impedance of the amplifying means2to the predetermined output impedance (for example, 50Ω) of the regulating means3(non-reciprocal circuits3aand3b), two-step impedance conversion is implemented by making a change to the configuration of the matching means4and by making a change to the configuration of the passive elements and the isolators30aand30bof the non-reciprocal circuits3aand3b. It is thus possible to increase the design flexibility of the circuit module1.

The isolators30aand30bare disposed such that the magnetic poles N and S of the permanent magnets32of the isolators30aand30bare aligned, or such that both magnetic poles N and S of a permanent magnet32of one isolator are disposed adjacent to the magnetic poles S and N, which are the opposite polarities of the above-described magnetic poles N and S, respectively, of a permanent magnet32of the other isolator, or such that a straight line formed by both magnetic poles N and S of a permanent magnet32of one isolator intersects with a straight line formed by both magnetic poles N and S of a permanent magnet32of the other isolator. With this arrangement, one magnetic pole N of a permanent magnet32of one non-reciprocal circuit3ais disposed adjacent to a magnetic pole S, which is the opposite polarity of the magnetic pole N, of a permanent magnet32of the other non-reciprocal circuit3b. As a result, it is possible to reliably and efficiently intensity DC magnetic fields H of the permanent magnets32of both of the isolators30aand30b.

In the circuit module1, transmission signals of multiple frequency bands or different communication systems can be amplified with low insertion and with high efficiency. Accordingly, it is not necessary to individually provide transmission routes for different frequency bands or different communication systems, and instead, transmission signals of different frequency bands can be amplified and transmitted by the common circuit module1, thereby enhancing the efficiency and also simplifying the components of a device on which the circuit module1is mounted.

More specifically, as stated above, the circuit module1exhibiting excellent transmission characteristics and isolation characteristics in a wide band is suitably used in a multiband, multimode communication system, such as a communication system that performs wireless communication by supporting Band 1, Band 2, and Band 3 of the W-CDMA method, GSM 1800 method, and GSM 1900 method, a communication system that performs wireless communication by supporting Band 5 and Band 8 of the W-CDMA method, GSM 800 method, and GSM 900 method, and a communication system that performs wireless communication by supporting Band 1, Band 2, and Band 3 of the W-CDMA method and Band 1, Band 2, and Band 3 of the LTE method.

Second Embodiment

A second embodiment of a circuit module of the present invention will be described below with reference toFIG. 10.FIG. 10is a block diagram illustrating the second embodiment of a circuit module of the present invention.

A circuit module1ashown inFIG. 10is different from the above-described circuit module1in the following points. The amplifying means2includes a single power amplifier2cfor amplifying transmission signals of different frequency bands input from an input terminal PIc. The matching means4includes a matching circuit4chaving a filter function of outputting transmission signals amplified by the amplifying means2(power amplifier2c) to the non-reciprocal circuits3aand3b. The configurations of the other elements are similar to those of the above-described embodiment, and thus, the other elements are designated by like reference numerals, and an explanation thereof will be omitted. As the configurations of the power amplifier2cand the matching circuit4c, any known configuration may be used, and thus, a detailed explanation thereof will be omitted.

In this embodiment, in addition to advantages similar to those obtained by the above-described embodiment, the following advantages are also achieved. It is not necessary to individually provide power amplifiers for transmission signals of different frequency bands, thereby simplifying the configuration of the amplifying means2. It is thus possible to provide a simple, practical circuit module1a.

The present invention is not restricted to the above-described embodiments, and various modifications other than the modifications discussed above may be made without departing from the spirit of the invention. For example, the characteristics of the circuit modules1and1aare only examples, and the configurations of the amplifying means2, the regulating means3, and the matching means4may be suitably designed as described above according to the frequency band to be used or the configuration of a wireless communication device or a mobile communication terminal in which the circuit module1is used.

In the above-described embodiments, the regulating means3includes two non-reciprocal circuits3aand3b. However, the number of non-reciprocal circuits included in the regulating means3is not restricted to two, and the regulating means3may include three or more non-reciprocal circuits so that the circuit module1can process more transmission signals. Additionally, the arrangement state of the isolators included in the non-reciprocal circuits is not restricted to the above-described examples, and the isolators may be arranged in any manner as long as the DC magnetic field H of one permanent magnet is intensified by the DC magnetic field of another permanent magnet.

The configuration of each of the non-reciprocal circuits3aand3bis not restricted to a configuration including the above-described isolator30. Instead, a known isolator having another configuration may be suitably used as each of the non-reciprocal circuits3aand3b. The non-reciprocal circuit3may be constituted by a circulator.

Electronic components disposed on a substrate included in the circuit module1are not restricted to the above-described examples, and optimal electronic components may be suitably selected and mounted on the substrate according to the intended use or the design of the circuit module1. For example, an interstage filter (SAW filter) or a power detector may also be mounted on the circuit module1, or a switch, a multiplexer, such as a diplexer, or a coupler may also be mounted on the circuit module1. The above-described passive elements, such as the inductors L3and L11, the capacitors C1, C2, and C11, and the terminator R, do not have to be chip components mounted on the substrate, but may be components integrated in the substrate or may be formed by a wiring pattern within the substrate. The transistor of the amplifier element20may be constituted by a known amplifier element, such as an FET, instead of the above-described HBT.

In the above-described embodiments, the matching means4(matching circuits4aand4b) is formed as a single-stage low pass filter. However, the matching means4may be formed in any manner, such as a multiple-stage (for example, two-stage or three-stage) low pass filter or a high pass filter. The matching means4may be formed as a known circuit configuration according to the necessity.

The present invention is widely applicable to a circuit module including amplifying means for amplifying multiple types of signals.1,1acircuit module2amplifying means2cpower amplifier3regulating means3a,3bnon-reciprocal circuit30a,30bisolator31ferrite (magnetic body)32permanent magnet33first center electrode34second center electrode35input port36output port37ground port4matching meansH DC magnetic fieldN one magnetic poleS opposite magnetic pole