JP2006042394A - Balanced high-frequency circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balanced high-frequency circuit possessing improved balance characteristics. <P>SOLUTION: The balanced high-frequency circuit, in which a filter having first balanced terminals is connected to a device having second balanced terminals via the balanced terminals, is connected between balanced transmission lines. The balanced high-frequency circuit is provided with a phase circuit 1103 of a series resonance circuit, having three reactance elements 1104, 1105, 1106, wherein the imaginary parts of the two reactance elements 1104, 1105 differ in polarity from that of the other reactance element 1106. As for the differential signal components of the signal, a virtual grounding plane is formed in between the two reactance elements, and increases the impedance in each of the two reactance elements 1104, 1105. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a balanced high-frequency circuit using a balanced high-frequency device such as a surface acoustic wave filter or a high-frequency amplifier.

  In recent years, with the development of mobile communication, higher performance and smaller size of devices used are expected. Furthermore, for the purpose of improving noise characteristics against crosstalk between devices, etc., balancing (balancing) of filters and semiconductor elements used in the RF stage has progressed, and good balance characteristics are required. Conventionally, surface acoustic wave filters have been widely used for filters. In particular, the longitudinal mode type surface acoustic wave filter can easily realize balanced-unbalanced conversion due to the configuration of the IDT electrode, and has a low loss, high attenuation, and good balance as an RF stage filter having balanced input / output terminals. Characteristics are expected.

  Hereinafter, a conventional balanced high frequency device will be described. FIG. 28 shows a configuration of a conventional balanced high-frequency device 2801. The balanced high-frequency device 2801 includes an input terminal IN that is an unbalanced input / output terminal and output terminals OUT1 and OUT2 that are balanced input / output terminals.

  In balanced high-frequency devices, impedance matching is required. FIG. 29 shows an example of the configuration of a conventional balanced high-frequency device having a matching circuit. In FIG. 29A, the balanced high-frequency device 2901 includes an input terminal IN that is an unbalanced input / output terminal and output terminals OUT1 and OUT2 that are balanced input / output terminals. Further, a matching circuit 2902 is connected between the output terminals. In FIG. 29B, the balanced high-frequency device 2903 includes an input terminal IN that is an unbalanced input / output terminal and output terminals OUT1 and OUT2 that are balanced input / output terminals. Further, matching circuits 2904 and 2905 are connected between the output terminals OUT1 and OUT2 and the ground plane, respectively. Such a matching circuit has been used to match the balanced high-frequency device and the characteristic impedance of the balanced input / output terminal.

  A conventional surface acoustic wave filter will be described as an example of such a balanced high-frequency device. FIG. 30 is a configuration diagram of a surface acoustic wave filter 3001 having balanced input / output terminals. In FIG. 30, a surface acoustic wave filter 3001 includes first, second, and third interdigital transducer electrodes (hereinafter referred to as IDT electrodes) 3003, 3004, and 3005, and first and second electrodes on a piezoelectric substrate 3002. It is constituted by reflector electrodes 3006 and 3007. One electrode finger of the first IDT electrode 3003 is connected to the output terminal OUT1, and the other electrode finger of the first IDT electrode 3003 is connected to the output terminal OUT2. Also, one electrode finger of the second and third IDT electrodes 3004 and 3005 is connected to the input terminal IN, and the other is grounded. With the above configuration, a surface acoustic wave filter having an unbalanced-balanced input / output terminal can be realized. In the surface acoustic wave filter shown in FIG. 30, the impedance of the input / output terminals is designed to be 50Ω.

  A conventional surface acoustic wave filter will be described as an example of a balanced high-frequency device having a matching circuit. FIG. 31 is a configuration diagram of a surface acoustic wave filter 3101 having a matching circuit. In FIG. 31, a surface acoustic wave filter 3101 includes first, second, and third interdigital transducer electrodes (hereinafter referred to as IDT electrodes) 3103, 3104, and 3105 and first and second electrodes on a piezoelectric substrate 3102. The reflector electrodes 3106 and 3107 are included. The first IDT electrode 3103 is divided into two divided IDT electrodes, one electrode finger of the first divided IDT electrode 3108 is connected to the output terminal OUT1, and one electrode finger of the second divided IDT electrode 3109 is output. The other electrode finger of the first and second divided IDT electrodes is electrically connected to the terminal OUT2. One electrode finger of the second and third IDT electrodes 3104 and 3105 is connected to the input terminal IN, and the other is grounded. Further, an inductor 3110 is connected between the output terminals as a matching circuit. With the above configuration, a surface acoustic wave filter having an unbalanced-balanced input / output terminal can be realized. In the surface acoustic wave filter of FIG. 31, the input / output terminal impedance is designed to be 50Ω on the input side and 150Ω on the output side, and has an impedance conversion function.

  FIG. 32 is a characteristic diagram of the conventional 900 MHz band surface acoustic wave filter shown in FIG. In FIG. 32, (a) is a pass characteristic, (b) is an amplitude balance characteristic in a pass band (925 MHz to 960 MHz), and (c) is a phase balance characteristic in the pass band. From FIG. 32, in the pass band, the amplitude balance characteristic is greatly degraded from −0.67 dB to +0.77 dB, and the phase balance characteristic is significantly degraded from −6.3 ° to + 9.4 °.

  Here, the amplitude balance characteristic represents the amplitude difference between the signal amplitude of the input terminal IN and the output terminal OUT1 and the signal amplitude of the input terminal IN and the output terminal OUT2, and this value cannot be zero. There is no deterioration of the balance characteristics. The phase balance characteristic represents a deviation from 180 ° of the phase difference between the signal phase of the input terminal IN and the output terminal OUT1 and the signal phase of the input terminal IN and the output terminal OUT2. If the value is zero, there is no deterioration of the balance characteristic.

  However, the above-described balanced high-frequency device and the surface acoustic wave filter described as an example thereof have a problem that the balance characteristic, which is one of important electrical characteristics, is greatly deteriorated.

  An object of the present invention is to provide a balanced high-frequency circuit having a good balance characteristic by deriving a method for improving the balance characteristic by considering the cause of deterioration of the balanced high-frequency device.

In order to solve the above-described problem, the first aspect of the present invention provides a filter having a first balanced terminal and a device having a second balanced terminal via the first and second balanced terminals. A balanced high-frequency circuit connected between the balanced transmission lines to be connected,
A balanced input terminal connected to the first balanced terminal;
A balanced output terminal connected to the second balanced terminal;
A phase circuit electrically connected between at least one of the balanced input terminals or between the balanced output terminals;
The phase circuit is a parallel resonant circuit that resonates in parallel with a ground plane with respect to a predetermined frequency with respect to a differential signal component of a signal flowing through the balanced transmission line, and the parallel resonant circuit includes at least three A first reactance element is connected between one of the balanced input terminals or one of the balanced output terminals and a ground plane, and the other of the balanced input terminals or the A second reactance element is connected between the other of the balanced output terminals and the ground plane, and a third reactance element is connected between the balanced input terminals or between the balanced output terminals, The imaginary part of the impedance of the first and second reactance elements and the imaginary part of the impedance of the third reactance element are different in polarity, and the in-phase signal component of the signal is Then, the impedance of one of the balanced input terminals or one of the balanced output terminals and the ground plane, and the impedance of the other of the balanced input terminals or the other of the balanced output terminals and the ground plane are: It is a balanced high-frequency circuit that reduces the in-phase signal component of the signal by being not more than twice the characteristic impedance of the first balanced terminal or the second balanced terminal.

  In the second aspect of the present invention, the impedance of the in-phase signal component of the signal with respect to the ground plane is 0.5 times or less the characteristic impedance of the first balanced terminal or the second balanced terminal. It is a balanced high-frequency circuit of the present invention.

According to a third aspect of the present invention, there is provided a balanced transmission line connecting a filter having a first balanced terminal and a device having a second balanced terminal via the first and second balanced terminals. A balanced high-frequency circuit connected,
A balanced input terminal connected to the first balanced terminal;
A balanced output terminal connected to the second balanced terminal;
A phase circuit electrically connected between at least one of the balanced input terminals or between the balanced output terminals;
The phase circuit is a series resonance circuit that resonates in series with a ground plane with respect to a predetermined frequency with respect to an in-phase signal component of a signal flowing through the balanced transmission line, and the series resonance circuit includes at least three series resonance circuits. The first and second reactance elements are connected between one of the balanced input terminals or one of the balanced output terminals and a ground plane. A third reactance element is connected between the connection point of the second reactance element and the ground plane, and the imaginary part of the impedance of the first and second reactance elements and the impedance of the third reactance element With respect to the differential signal component of the signal, a virtual ground plane is formed between the first and second reactance elements, the polarity of the imaginary part is different, and the first and second The impedance of one of the balanced input terminals or one of the balanced output terminals and the virtual ground plane and the other of the balanced input terminals or the balanced output terminal Is a balanced high-frequency circuit that reduces the in-phase signal component of the signal by the series resonance circuit.

  As is apparent from the above description, the present invention can provide a balanced high-frequency circuit having a good balance characteristic.

  Hereinafter, various embodiments of a balanced high-frequency circuit according to the present invention and a balanced high-frequency device related to the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, the balanced high-frequency device according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a balanced high-frequency device 101 according to the first embodiment of the present invention. In FIG. 1, the balanced high-frequency device 101 includes a balanced element 102 and a phase circuit 103. In the balanced element 102, the input-side terminal is an input terminal IN which is an unbalanced input / output terminal, and the output-side terminals are output terminals OUT1 and OUT2 which are balanced input / output terminals. Further, a phase circuit 103 is connected between the output terminals. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be realized.

  First, the cause of the deterioration of the balance characteristics of the balanced high-frequency device will be discussed using a surface acoustic wave filter. The conventional surface acoustic wave filter 201 shown in FIG. 30 has a problem that the balance characteristics deteriorate. Here, the balance characteristic was analyzed with the configuration shown in FIG. In FIG. 2, the surface acoustic wave filter 201 includes an ideal surface acoustic wave filter 202 having no deterioration in balance characteristics and capacitive components 203 and 204. By connecting the capacitive components 203 and 204 between the input side and the output side of the ideal surface acoustic wave filter 202, the coupling by the parasitic components of the surface acoustic wave filter 201 is assumed.

  FIG. 3 shows filter characteristics when these capacitance components 203 and 204 are 0.1 pF. 3, (a) shows the amplitude balance characteristic in the pass band, and (b) shows the phase balance characteristic in the pass band. The analysis result of the balance characteristic in FIG. 3 agrees very well with the measured characteristic of the conventional surface acoustic wave filter shown in FIG. 32 as the tendency of the balance characteristic deterioration. Therefore, it is considered that the main factor for the deterioration of the balance characteristic is the coupling between the input terminal and the output terminal of the balanced element.

  Next, the operation of the balanced high-frequency device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 4 shows an outline of the operation of the balanced high-frequency device 101 in the first embodiment of the present invention. Regarding the deterioration of the balance characteristic of the balanced high-frequency device 101, the coupling due to the parasitic component between the input terminal and the output terminal is considered as a main factor. This is considered to be explained by expressing the signal component flowing through the balanced input / output terminal using the in-phase signal component and the differential signal component. That is, the signal component i input from the input terminal IN is differentially output as the differential signal components id1 and id2 by the balanced element 102. However, the coupling due to the parasitic component is not differentiated to each of the output terminals OUT1 and OUT2, but is superimposed as the in-phase signal components ic1 and ic2, and the in-phase signal components ic1 and ic2 cause the balance characteristics to deteriorate. Become.

  Therefore, in the embodiment of the present invention, the phase circuit 103 operates as a resonance circuit at a predetermined frequency, and the impedances of the in-phase signal components ic1 and ic2 viewed from the balanced element 102 on the output terminal side are output from the balanced element 102. By making the impedance lower than the impedance of the differential signal components id1 and id2 viewed from the terminal side, the in-phase signal components ic1 and ic2 can be reduced.

  As described above, the balanced high-frequency device 101 of the present invention can realize a balanced high-frequency device with excellent balance characteristics by reducing the in-phase signal components ic1 and ic2 using the phase circuit 103. .

  In this embodiment, the input terminal is the input terminal IN which is an unbalanced input / output terminal, and the output terminal is the output terminals OUT1 and OUT2 which are balanced input / output terminals. In the above description, the phase circuit 103 is connected, but the present invention is not limited to this. The input terminal is an input terminal that is a balanced input / output terminal, the output terminal is an output terminal that is an unbalanced input / output terminal, and the phase circuit 103 may be connected between the input terminals. Absent.

(Embodiment 2)
Hereinafter, a balanced high-frequency device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows the configuration of a balanced high-frequency device 501 according to the second embodiment of the present invention. In FIG. 5, the balanced high-frequency device 501 includes a balanced element 502 and phase circuits 503 and 504. In the balanced element 502, the input terminal is an input terminal IN which is a balanced input / output terminal, and the output terminals are output terminals OUT1 and OUT2 which are balanced input / output terminals. With the above configuration, a balanced high-frequency device having a balanced-balanced input / output terminal can be realized.

  Also in the balanced high-frequency device 501 of the present invention, the phase circuit 503 operates as a resonant circuit at a predetermined frequency, and the impedance of the in-phase signal components ic1 and ic2 viewed from the balanced element 502 on the input terminal side is determined from the balanced element 502. The phase circuit 504 operates as a resonance circuit at a predetermined frequency by lowering the impedance of the differential signal components id1 and id2 viewed from the input terminal side, and the in-phase signal components ic1 viewed from the balanced element 502 to the output terminal side. By making the impedance of ic2 lower than the impedance of the differential signal components id1 and id2 as seen from the balanced element 502 on the output terminal side, the balanced high frequency device having excellent balance characteristics by reducing the in-phase signal components ic1 and ic2 Can be realized.

(Embodiment 3)
Hereinafter, a balanced high-frequency device according to a third embodiment of the present invention will be described with reference to the drawings. Here, a more specific circuit configuration is shown as the phase circuit. FIG. 6 shows the configuration of a balanced high-frequency device 601 according to the second embodiment of the present invention. In FIG. 6, the balanced high-frequency device 601 includes a balanced element 602 and a phase circuit 603. In the balanced element 602, the input terminal is an input terminal IN which is an unbalanced input / output terminal, and the output terminals are output terminals OUT1 and OUT2 which are balanced input / output terminals. Further, the phase circuit 603 is constituted by a transmission line 604 and is arranged between output terminals. The length of the transmission line 604 is λ / 2 (where λ is the wavelength), and the phase change amount is 180 °. Here, λ is a length with respect to a frequency in the pass band or in the vicinity of the pass band. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be realized.

  Next, the operation of the balanced high-frequency device 601 will be described using the drawings. As shown in FIG. 7A, when a signal component i is input to the balanced element 602 from the input terminal IN, the in-phase signal components ic1 and ic2 and the differential signal components id1 and id2 are output from the balanced element. Is output. The transmission line 604 disposed between the output terminals operates differently for the in-phase signal components ic1 and ic2 and the differential signal components id1 and id2. That is, for the in-phase signal components ic1 and ic2, as shown in FIG. 7B, the output terminals OUT1 and OUT2 are connected to the open λ / 4 lines, respectively, and operate as a series resonance circuit. Thus, the impedance of the output terminal with respect to the ground plane approaches a short circuit, and the in-phase signal components ic1 and ic2 are not transmitted to the output terminals OUT1 and OUT2.

  Further, regarding the differential signal components id1 and id2, since a virtual ground plane is provided at the midpoint of the transmission line 604, a short-circuited λ / 4 line is connected to each of the output terminals OUT1 and OUT2 in parallel. By operating as a resonance circuit, the impedance of the output terminal with respect to the ground plane approaches open, and the differential signal components id1 and id2 are transmitted to the output terminals OUT1 and OUT2.

  As described above, the balanced high-frequency device according to the third embodiment of the present invention can reduce in-phase signal components by using the transmission line 604 as the phase circuit, and has a balanced high-frequency characteristic with excellent balance characteristics. A device can be realized.

  In this embodiment, the phase circuit is configured by a transmission line. However, this configuration is not limited to this, and the same effect as the present invention can be obtained if the configuration operates as a phase circuit. It is done.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is described as an unbalanced type and the output terminal is described as a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 4)
Hereinafter, a balanced high-frequency device according to a fourth embodiment of the present invention will be described with reference to the drawings. Here, a more specific circuit configuration is shown as the phase circuit. FIG. 8 shows the configuration of a balanced high-frequency device according to the fourth embodiment of the present invention. In FIG. 8, the balanced high-frequency device 801 includes a balanced element 802 and a phase circuit 803. In the balanced element 802, the input terminal is an input terminal IN which is an unbalanced input / output terminal, and the output terminals are output terminals OUT1 and OUT2 which are balanced input / output terminals.

  The phase circuit 803 includes impedance elements 804, 805, and 806. At this time, the output terminals OUT1 and OUT2 are grounded via the impedance elements 804 and 805, respectively, the impedance element 806 is connected between the output terminals, and the phase circuit 803 is connected between the output terminals. Here, the impedance elements 804 and 805 have substantially the same impedance, and the imaginary part of the impedance of the impedance element 806 is opposite in polarity to the imaginary part of the impedance of the impedance elements 804 and 805. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be obtained.

  Next, the operation of the balanced high-frequency device according to Embodiment 4 of the present invention will be described using specific impedance elements. FIG. 9 is an operation explanatory diagram of the balanced high-frequency device according to the fourth embodiment of the present invention. As shown in FIG. 9A, the phase circuit 901 includes capacitors 902 and 903 and an inductor 904. As shown in FIG. 9A, when the signal component i is input to the balanced element 802 from the input terminal IN, the in-phase signal components ic1 and ic2 and the differential signal components id1 and id2 are output from the balanced element. Is output. Here, the inductor 904 connected between the output terminals forms a virtual ground point 905 for the differential signal components id1 and id2.

  FIG. 9B shows an equivalent circuit of the phase circuit 901 related to the differential signal components id1 and id2. With respect to the differential signal components id1 and id2, the inductor 904 forms a virtual ground point 905. Therefore, the capacitor 902 and a part of the inductor 904 are output at the output terminal OUT1, and the capacitor 903 and a part of the inductor 904 are output at the output terminal OUT2. Will form a parallel resonant circuit with respect to the ground plane, and by designing the parallel resonant frequency to be in the pass band or in the vicinity of the pass band, the differential signal components id1 and id2 having a predetermined frequency. Is transmitted to the output terminal without being short-circuited to the ground plane. That is, the differential signal component is substantially the same as the operation shown in FIG. FIG. 9C shows an equivalent circuit of the phase circuit 901 related to the in-phase signal components ic1 and ic2. Regarding the in-phase signal component, OUT1 and OUT2 have substantially the same potential, the inductance 904 does not form a virtual ground point for the in-phase signal components ic1 and ic2, and OUT1 and OUT2 are substantially open. Here, the part of the inductor 904 means up to the virtual ground point 905 (see FIG. 9B).

  Therefore, by designing the impedances of the capacitors 902 and 903 as impedance elements disposed between the balanced input / output terminals OUT1 and OUT2 and the ground plane to be sufficiently small, the common-mode signal components ic1 and ic2 Is not short-circuited to the balanced input / output terminal.

  Further, the phase circuit according to Embodiment 4 of the present invention may have the configuration shown in FIG. FIG. 10 is an operation explanatory diagram of the balanced high-frequency device according to the fourth embodiment of the present invention. As shown in FIG. 10A, the phase circuit 1001 includes inductors 1002 and 1003 and a capacitor 1004. As shown in FIG. 10A, when the signal component i is input from the input terminal IN to the balanced element 802, the balanced element receives in-phase signal components ic1 and ic2 and differential signal components id1 and id2. Is output. Here, the capacitor 1004 connected between the output terminals forms a virtual ground point 1005 for the differential signal components id1 and id2.

  FIG. 10B shows an equivalent circuit of the phase circuit 1001 related to the differential signal components id1 and id2. As shown in FIG. 10B, with respect to the differential signal components id1 and id2, the capacitor 1004 forms a virtual ground point 1005 with respect to the differential signal components id1 and id2. Therefore, on the output terminal OUT1 side, the inductor 1002 and the capacitor On the output terminal OUT2 side, a part of 1004 and the inductor 1003 and a part of the capacitor 1004 form a parallel resonance circuit with respect to the ground plane, and this parallel resonance frequency is within the pass band or passes. By designing to be in the vicinity of the band, the differential signal components id1 and id2 having a desired frequency are transmitted to the output terminal without being short-circuited to the ground plane because the impedance with respect to the ground plane approaches infinity. That is, the differential signal components id1 and id2 are substantially the same as the operation shown in FIG. FIG. 10C shows an equivalent circuit of the phase circuit 1001 related to the in-phase signal components ic1 and ic2. Regarding the in-phase signal component, OUT1 and OUT2 are substantially at the same potential, and the capacitor 1004 does not form a virtual ground point for the in-phase signal components ic1 and ic2, and OUT1 and OUT2 are substantially open. Here, a part of the capacitor 1004 means up to a virtual ground point (see FIG. 10B).

  Therefore, by designing the impedances of the inductors 1002 and 1003 as impedance elements arranged between the balanced input / output terminals OUT1 and OUT2 and the ground plane to a sufficiently small value, the in-phase signal components ic1 and ic2 Is not short-circuited to the balanced input / output terminal.

  As described above, the balanced high-frequency device according to the fourth embodiment of the present invention can reduce in-phase signal components by using three impedance elements as the phase circuit, and has a balanced type with excellent balance characteristics. A high frequency device can be realized.

  In the present embodiment, the number and configuration of inductors and capacitors as impedance elements constituting the phase circuit are not limited to this, and the element values of the impedance elements 804 and 805 are substantially the same. These are not necessarily the same, and are optimally selected depending on the circuit configuration. If the configuration operates as a phase circuit, the same effect as the present invention can be obtained.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is an unbalanced type and the output terminal is a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 5)
Hereinafter, a balanced high-frequency device according to a fifth embodiment of the present invention will be described with reference to the drawings. Here, a more specific circuit configuration is shown as the phase circuit. FIG. 11 shows the configuration of a balanced high frequency device 1101 according to the fifth embodiment of the present invention. In FIG. 11, the balanced high-frequency device 1101 includes a balanced element 1102 and a phase circuit 1103. In the balanced element 1102, the input-side terminal is an input terminal IN which is an unbalanced input / output terminal, and the output-side terminals are output terminals OUT1 and OUT2 which are balanced terminals.

  The phase circuit 1103 includes impedance elements 1104, 1105, and 1106. The impedance elements 1104 and 1105 are connected in series between the output terminals, the midpoint 1107 of the impedance elements 1104 and 1105 is grounded via the impedance element 1106, and the phase circuit 1103 is connected between the output terminals. Here, the polarity of the imaginary part of the impedance of the impedance element 1106 is opposite to the polarity of the imaginary part of the impedance of the impedance elements 1104 and 1105. Moreover, the impedance elements 1104 and 1105 have substantially the same impedance. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be obtained.

  Next, the operation of the balanced high-frequency device of the present invention will be described using specific impedance elements. FIG. 12 is an explanatory diagram of the operation of the balanced high-frequency device of the present invention. As shown in FIG. 12A, the phase circuit 1201 includes inductors 1202 and 1203 and a capacitor 1204. As shown in FIG. 12A, when the signal component i is input from the input terminal IN to the balanced element 1102, the balanced element 1102 outputs the in-phase signal components ic1 and ic2 and the differential signal components id1 and id2. Is output. FIG. 12B shows an equivalent circuit of the phase circuit 1201 with respect to the differential signal component. As shown in FIG. 12B, with respect to the differential signal components id1 and id2, the connection point 1205 between the inductors 1202 and 1203 is a virtual ground point. Therefore, by increasing the values of the inductors 1202 and 1203 sufficiently, The impedance with respect to the ground can be increased, and the differential signal components id1 and id2 are transmitted to the output terminals OUT1 and OUT2.

  FIG. 12C shows an equivalent circuit of the phase circuit 1201 with respect to the in-phase signal component. As shown in FIG. 12C, with respect to the in-phase signal components ic1 and ic2, the connection point 1205 between the inductors 1202 and 1203 does not become a virtual ground point, so the inductor 1202 and part of the capacitor 1204, the inductor 1203 and the capacitor 1204, and so on. Are designed to form a series resonant circuit at a predetermined frequency, the in-phase signal component is short-circuited to the ground plane and is not transmitted to the output terminals OUT1 and OUT2. Here, a part of the capacitor 1204 means one equivalently connected in parallel (see FIG. 12C).

  The phase circuit of the present invention may have the configuration shown in FIG. FIG. 13 is an explanatory diagram of the operation of the balanced high-frequency device of the present invention. As shown in FIG. 13A, the phase circuit 1301 includes capacitors 1302 and 1303 and an inductor 1304. As shown in FIG. 13A, when the signal component i is input from the input terminal IN to the balanced element 1102, the balanced element 1102 outputs the in-phase signal components ic1 and ic2 and the differential signal components id1 and id2. Is output. FIG. 13B shows an equivalent circuit of the phase circuit 1301 with respect to the differential signal components id1 and id2. As shown in FIG. 13B, with respect to the differential signal components id1 and id2, the connection point 1305 between the capacitors 1302 and 1303 is a virtual ground point. Therefore, by making the values of the capacitors 1302 and 1303 sufficiently small, The impedance with respect to the ground can be increased, and the differential signal component is transmitted to the output terminals OUT1 and OUT2.

  FIG. 13C shows an equivalent circuit of the phase circuit 1301 with respect to the in-phase signal components ic1 and ic2. As shown in FIG. 13C, with respect to the in-phase signal components ic1 and ic2, the connection point 1305 between the capacitors 1302 and 1303 does not become a virtual ground point, so the capacitor 1302 and part of the inductor 1304, the capacitor 1303 and the inductor 1304 Are designed to form a series resonant circuit at a predetermined frequency, the in-phase signal component is short-circuited to the ground plane and is not transmitted to the output terminals OUT1 and OUT2. Here, a part of the inductor 1304 means one equivalently connected in parallel (see FIG. 13C).

  As described above, the balanced high-frequency device according to the fifth embodiment of the present invention can reduce in-phase signal components by using three impedance elements as the phase circuit, and is a balanced type with excellent balance characteristics. A high frequency device can be realized.

  In the present embodiment, the number and configuration of inductors and capacitors as impedance elements constituting the phase circuit are not limited to this, and the element values of the impedance elements 1104 and 1105 are substantially the same. These are not necessarily the same, and are optimally selected depending on the circuit configuration. If the configuration operates as a phase circuit, the same effect as the present invention can be obtained.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is an unbalanced type and the output terminal is a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 6)
Hereinafter, a balanced high-frequency device according to a sixth embodiment of the present invention will be described with reference to the drawings. Here, a specific configuration of the balanced high-frequency device will be described in the case where a surface acoustic wave filter is used as the balanced element. FIG. 14 shows the configuration of the balanced device of the present invention. In FIG. 14, a balanced high-frequency device 1401 includes a surface acoustic wave filter 1402 and a phase circuit 1403 that are balanced elements. In the surface acoustic wave filter 1402, the input terminal is an input terminal IN which is an unbalanced input / output terminal, and the output terminals are output terminals OUT 1 and OUT 2 which are balanced input / output terminals. Further, a phase circuit 1403 is connected between the output terminals.

  The surface acoustic wave filter 1402 includes first, second, and third interdigital transducer electrodes (hereinafter referred to as IDT electrodes) 1405, 1406, and 1407 and first and second reflector electrodes 1408 on a piezoelectric substrate 1404. , 1409. One electrode finger of the first IDT electrode 1405 is connected to the output terminal OUT1, and the other electrode finger of the first IDT electrode 1405 is connected to the output terminal OUT2. One electrode finger of the second and third IDT electrodes 1406 and 1407 is connected to the input terminal IN, and the other is grounded. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be obtained.

  Next, specific characteristics of the balanced high-frequency device in the present embodiment will be shown. FIG. 15 shows characteristics of the balanced high-frequency device 1401 when the phase circuit 603 shown in FIG. 6 is used as the phase circuit 1403. Here, the length of the transmission line 604 constituting the phase circuit 603 is λ / 2, and the phase amount as the phase circuit is 180 °. In FIG. 15, (a) is a pass characteristic, (b) is an amplitude balance characteristic of the pass band, and (c) is a phase balance characteristic of the pass band. Compared to the conventional characteristic shown in FIG. 32, the balance characteristic is greatly improved, and the characteristic is almost close to the ideal state. Further, with respect to the pass characteristics, the attenuation on the high side of the pass band is improved by about 5 dB.

  Next, the case where the length of the transmission line 604 was changed was evaluated. FIG. 16 shows balance characteristics when the length of the transmission line 604 is changed. In FIG. 16, (a) is an amplitude balance characteristic, and (b) is a phase balance characteristic. Reference numerals 1601 and 1602 denote the maximum and minimum values of deterioration in the amplitude balance characteristics in the passband in the surface acoustic wave filter of the present embodiment, respectively. 1603 and 1604 denote the deterioration in the surface acoustic wave filter of the present embodiment. It is the maximum value and the minimum value of the deterioration in the phase balance characteristic in the pass band. Also, the broken lines indicate the maximum value and the minimum value of the deterioration of balance characteristics in the conventional surface acoustic wave filter. From FIG. 16, the balance characteristic is improved in the range of the transmission line length from λ / 4 to 3λ / 4. Further, by setting the phase amount in the range of 3λ / 8 to 5λ / 8, the amplitude balance characteristic is approximately −5 dB to +5 dB, and the phase balance characteristic is approximately in the range of −0.5 ° to + 0.5 °. Balance characteristics can be obtained.

  Next, characteristics when a phase circuit of another configuration is used are shown. FIG. 17 shows the characteristics of the balanced high-frequency device 1401 when the phase circuit 901 shown in FIG. 9 is used as the phase circuit 1403. Here, the capacitances of the capacitors 902 and 903 are designed such that Cg1 and Cg2 have substantially the same value, and the impedance is 3Ω at the passband frequency. The inductance Lb of the inductor 904 is designed so that the parallel resonance frequencies of Cg1 and Lb / 2 and Cg2 and Lb / 2 are in the passband.

  In FIG. 17, (a) is a pass characteristic, (b) is an amplitude balance characteristic of the pass band, and (c) is a phase balance characteristic of the pass band. Compared to the conventional characteristic shown in FIG. 32, the balance characteristic is greatly improved, and the characteristic is almost close to the ideal state. Further, with respect to the pass characteristics, the attenuation on the high side of the pass band is improved by about 5 dB.

  Next, evaluation was performed when the impedance of the capacitors 902 and 903 changed. FIG. 18 shows a balance characteristic with respect to the normalized impedance obtained by dividing the impedance of the capacitors 902 and 903 by the characteristic impedance of the terminal. Here, since the characteristic impedance of the balanced output terminal is 50Ω, the characteristic impedance of each terminal is 25Ω. In FIG. 18, (a) is an amplitude balance characteristic, and (b) is a phase balance characteristic. Reference numerals 1801 and 1802 denote the maximum and minimum values of deterioration in the amplitude balance characteristics in the passband in the surface acoustic wave filter of the present embodiment, respectively, and 1803 and 1804 denote the deterioration values in the surface acoustic wave filter of the present embodiment, respectively. It is the maximum value and the minimum value of the deterioration in the phase balance characteristic in the pass band. As shown in FIG. 18, the balance characteristic is improved when the normalized impedance is 2 or less.

  Next, characteristics when a phase circuit having another configuration is used will be described. FIG. 19 shows characteristics of the balanced high-frequency device 1401 when the phase circuit 1001 shown in FIG. 10 is used as the phase circuit 1403. Here, the inductance values Lg1 and Lg2 of the inductors 1002 and 1003 are substantially the same value, and the impedance is designed to be 3Ω at the passband frequency. The capacitance Cb of the capacitor 1004 is designed so that the parallel resonance frequencies of Lg1 and 2Cb and Lg2 and 2Cb are within the passband.

  In FIG. 19, (a) is the pass characteristic, (b) is the amplitude balance characteristic of the pass band, and (c) is the phase balance characteristic of the pass band. Compared to the conventional characteristic shown in FIG. 32, the balance characteristic is greatly improved, and the characteristic is almost close to the ideal state. Further, with respect to the pass characteristics, the attenuation on the high side of the pass band is improved by about 5 dB.

  Next, evaluation was performed when the impedance of the inductors 1002 and 1003 changed. FIG. 20 shows a balance characteristic with respect to the normalized impedance obtained by dividing the impedance of the inductors 1002 and 1003 by the characteristic impedance of the terminal. Here, since the characteristic impedance of the balanced output terminal is 50Ω, the characteristic impedance of each terminal is 25Ω. In FIG. 20, (a) is an amplitude balance characteristic, and (b) is a phase balance characteristic. Further, 2001 and 2002 are the maximum and minimum values of deterioration in the amplitude balance characteristics in the passband in the surface acoustic wave filter of the present embodiment, respectively, and 2003 and 2004 are the values in the surface acoustic wave filter of the present embodiment, respectively. It is the maximum value and the minimum value of the deterioration in the phase balance characteristic in the pass band.

  As shown in FIG. 20, the phase balance characteristic is improved when the normalized impedance is 2 or less. Further, the amplitude balance characteristic can be improved in the range where the normalized impedance is 0.5 or less. Therefore, the normalized impedance should be in the range of 2 or less, and preferably the balance characteristic can be improved if the normalized impedance is in the range of 0.5 or less.

  As described above, the balanced high-frequency device 1401 according to Embodiment 6 of the present invention can reduce in-phase signal components by using three impedance elements as a phase circuit, and can achieve balanced characteristics with excellent balance characteristics. Type high frequency device can be realized.

  In this embodiment, the transmission line is used as the phase circuit. However, it is preferable that the transmission line length is substantially λ / 2. This is because as the transmission line length deviates from λ / 2, the phase circuit operates as an inductor or a capacitor, and the impedance in the vicinity of the passband 2101 viewing the balanced element from the output terminal side deviates from the matching state. For example, when the length of the transmission line is 3λ / 8, the impedance of the pass band 2101 is inductive as shown in FIG. In this case, as shown in FIG. 22, in the phase circuit 2201, a transmission line 604 as a phase circuit and a capacitor 2202 as a matching circuit may be connected in parallel between output terminals. With this configuration, as shown in FIG. 21B, the impedance in the vicinity of the passband 2102 when the balanced element is viewed from the output terminal side becomes the center of the Smith chart, and impedance matching can be realized. As described above, the phase circuit may include a matching circuit that performs impedance matching.

  Also, if the length of the transmission line is 3λ / 8, the phase amount is 135 °. By adding this matching circuit, the phase amount approaches 180 °, and the length of the transmission line is substantially reduced. Equivalent to approaching λ / 2. Therefore, by adding this matching circuit, the length of the transmission line can be shortened and downsizing can be realized.

  In the present embodiment, the phase circuit is configured using a transmission line or three impedance elements. However, the present invention is not limited to this configuration. Further, the number and configuration of inductors and capacitors as impedance elements are not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is an unbalanced type and the output terminal is a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 7)
Hereinafter, a balanced high-frequency device according to a seventh embodiment of the present invention will be described with reference to the drawings. Here, a specific configuration when the phase circuit includes a matching circuit will be described. FIG. 23 (a) shows the configuration of a balanced high-frequency device according to Embodiment 7 of the present invention. In FIG. 23A, the balanced high-frequency device 2301 includes a balanced element 2302 and a phase circuit 2303. In the balanced element 2302, the input-side terminal is an input terminal IN which is an unbalanced input / output terminal, and the output-side terminals are output terminals OUT1 and OUT2 which are balanced input / output terminals. Further, a phase circuit 2303 is connected between the output terminals.

  The phase circuit 2303 includes capacitors 2304 and 2305, which are impedance elements, an inductor 2306, and an inductor 2307 as a matching circuit. At this time, the output terminals OUT1 and OUT2 are grounded via capacitors 2304 and 2305, respectively, the inductor 2306 is connected between the output terminals, and the phase circuit 2303 is connected between the output terminals. Further, the phase circuit 2303 includes an inductor 2307 as a matching circuit.

  The inductor 2306 forms a virtual ground point 2308 for the differential signal component. Therefore, the capacitor 2304 and a part of the inductor 2306 at the output terminal OUT1, and the capacitor 2305 and a part of the inductor 2306 at the output terminal OUT2 form a parallel resonance circuit with respect to the ground plane. By designing the resonance frequency so that it is in the pass band or close to the pass band, the differential signal component of a predetermined frequency has an impedance approaching infinity with respect to the ground plane and is not short-circuited to the ground plane. It is transmitted to the output terminal. That is, the differential signal component is substantially the same as the operation shown in FIG.

  Further, the inductor 2306 does not form a virtual ground point for the in-phase signal component. Therefore, by designing the impedance of the capacitors 2304 and 2305 as impedance elements arranged between the balanced input / output terminals OUT1 and OUT2 and the ground plane to a sufficiently small value, the common-mode signal component is short-circuited to the ground plane. It is not transmitted to the balanced input / output terminal.

  As described above, the phase circuit 2303 in the present embodiment is configured such that the capacitors 2304 and 2305 and the inductor 2306 form a resonance circuit at a predetermined frequency and includes the inductor 2307 as a matching circuit. Therefore, it is possible to realize a balanced high-frequency device with reduced in-phase signal components and excellent balance characteristics.

  Further, the inductor 2307 can be incorporated into the inductor 2306. That is, a combined inductance 2309 of the inductor 2306 and the inductor 2307 may be used. In this case, since the inductor 2306 and the inductor 2307 are connected in parallel, assuming that the inductances of the inductors 2306 and 2307 and the combined inductor 2309 are Lb, Lm and Lt, respectively, Lt = (Lb × Lm) / (Lb + Lm) The inductance value can be reduced. In addition, the number of elements can be reduced, and the circuit configuration can be reduced in size.

  However, in this case, the meaning of the predetermined frequency is different. That is, when the capacitances of the capacitors 2304 and 2305 are Cg1 and Cg2, the parallel resonance frequencies f1 and f2 of the differential signal components at the respective output terminals in the matching state formed by the capacitors 2304 and 2305 and the inductance 2306 are f1 = 1. / {2π × √ (Lb / 2) × √ (Cg1)}, f2 = 1 / {2π × √ (Lb / 2) × √ (Cg2)}. Here, when the inductor 2307 as a matching circuit is included, the overall parallel resonance frequencies f1t and f2t are f1 = 1 / {2π × √ (Lt / 2) × √ (Cg1)}, f2 = 1 / {2π. × √ (Lt / 2) × √ (Cg2)}, which apparently shifts from a predetermined frequency.

  That is, the parallel resonance frequency of the entire phase circuit 2303 is shifted by the amount of the inductor Lm within the pass band or near the pass band. However, in the matching state, the capacitor 2304 and a part of the inductor 2306 are connected at the output terminal OUT1. In the output terminal OUT2, the capacitor 2305 and a part of the inductor 2306 form a parallel resonance circuit with respect to the ground plane, and if the impedance of the capacitors 2304 and 2305 with respect to the ground plane is sufficiently small, the common-mode signal component can be reduced. The effect is the same. Here, part of the inductor 2306 means up to the virtual ground plane.

  Note that the circuit configuration in the present embodiment is not limited to this, and as long as the operation of the matching circuit and the operation as the resonance circuit are substantially the same as those of the present invention, the circuit has excellent balance characteristics as in the present invention. A balanced high-frequency device can be realized.

  Further, although the values Cg1 and Cg2 of the capacitor as the impedance element are substantially the same and the values Lg1 and Lg2 of the inductor as the impedance element are substantially the same, this is not necessarily the same, and is optimal depending on the circuit configuration. It is chosen.

(Embodiment 8)
Hereinafter, a balanced high-frequency device according to an eighth embodiment of the present invention will be described with reference to the drawings. Here, specific characteristics of the balanced high-frequency device will be described in the case where a surface acoustic wave filter is used as the balanced element. FIG. 24 shows the configuration of a balanced high-frequency device 2401 of the present invention. In FIG. 24, a balanced high-frequency device 2401 includes a surface acoustic wave filter 2402 and a phase circuit 2403 that are balanced elements. In the surface acoustic wave filter 2402, the input side terminal is an input terminal IN which is an unbalanced input / output terminal, and the output side terminals are output terminals OUT1 and OUT2 which are balanced type input / output terminals. Further, a phase circuit 2403 is connected between the output terminals.

  The surface acoustic wave filter 2402 includes first, second, and third interdigital transducer electrodes (hereinafter referred to as IDT electrodes) 2405, 2406, and 2407 and first and second reflector electrodes 2408 on a piezoelectric substrate 2404. , 2409. The first IDT electrode 2405 is divided into two divided IDT electrodes, and one electrode finger of the first and second divided IDT electrodes 2410 and 2411 is connected to the output terminals OUT1 and OUT2. The other electrode fingers of the first and second divided IDT electrodes 2410 and 2411 are electrically connected, and the electrode fingers are virtually grounded. One electrode finger of the second and third IDT electrodes 2406 and 2407 is connected to the input terminal IN, and the other is grounded. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be obtained.

  Also in the balanced high-frequency device 2401 according to the eighth embodiment of the present invention, by using the phase circuit 2403, in-phase signal components can be reduced, and a balanced high-frequency device with excellent balance characteristics can be realized.

  In the present embodiment, the phase circuit may be configured using a transmission line or three impedance elements. Further, the configuration of the phase circuit is not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit. Further, the number and configuration of inductors and capacitors as impedance elements are not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is an unbalanced type and the output terminal is a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 9)
Hereinafter, a balanced high-frequency device according to a ninth embodiment of the present invention will be described with reference to the drawings. Here, specific characteristics of the balanced high-frequency device will be described in the case where a surface acoustic wave filter is used as the balanced element. FIG. 25 shows the configuration of a balanced high-frequency device 2501 according to the ninth embodiment of the present invention. In FIG. 25, a balanced high-frequency device 2501 includes a surface acoustic wave filter 2502 and a phase circuit 2503 which are balanced elements. In the surface acoustic wave filter 2502, the input-side terminal is an input terminal IN that is an unbalanced input / output terminal, and the output-side terminals are output terminals OUT1 and OUT2 that are balanced terminals. Further, a phase circuit 2503 is connected between the output terminals.

  The surface acoustic wave filter 2502 has first, second, and third interdigital transducer electrodes (hereinafter referred to as IDT electrodes) 2505, 2506, and 2507 and first and second reflector electrodes 2508 on a piezoelectric substrate 2504. , 2509. One electrode finger of the first IDT electrode 2505 is connected to the input terminal IN, and the other is grounded. One electrode finger of the second and third IDT electrodes 2506 and 2507 is connected to the output terminals OUT1 and OUT2, and the other electrode finger of the second and third IDT electrodes 2506 and 2507 is grounded. With the above configuration, a balanced high-frequency device having an unbalanced-balanced input / output terminal can be obtained.

  Also in the balanced high-frequency device 2501 of the present invention, by using the phase circuit 2503, the in-phase signal component can be reduced, and a balanced high-frequency device with excellent balance characteristics can be realized.

  In the present embodiment, the phase circuit may be configured using a transmission line or three impedance elements. Further, the configuration of the phase circuit is not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit. Further, the number and configuration of inductors and capacitors as impedance elements are not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal is an unbalanced type and the output terminal is a balanced type. However, the input terminal may be a balanced type and the output terminal may be an unbalanced type. Further, both the input terminal and the output terminal may be balanced.

(Embodiment 10)
The balanced high-frequency device according to the tenth embodiment of the present invention will be described below with reference to the drawings. FIG. 26 shows a configuration of balanced high-frequency device 2601 according to the tenth embodiment of the present invention. Here, a specific configuration of the balanced high-frequency device will be described in the case where a semiconductor element is used as the balanced element. In FIG. 26, a balanced high-frequency device 2601 includes a semiconductor element 2602 that is a balanced element and phase circuits 2603 and 2608. In the semiconductor element 2602, input terminals are input terminals IN 1 and IN 2 that are balanced input / output terminals, and output terminals are output terminals OUT 1 and OUT 2 that are balanced terminals. Further, a phase circuit 2603 is connected between the input terminals, and a phase circuit 2608 is connected between the output terminals.

  Next, the configuration of the semiconductor element 2602 will be described. Reference numerals 2604a, 2604b, 2605a, and 2605b are bipolar transistors, and 2606a and 2606b are inductors. The input terminal IN1 is connected to the base of the bipolar transistor 2604a via the DC cut capacitor 2607a, and the input terminal IN2 is connected to the base of the bipolar transistor 2604b via the DC cut capacitor 2607b. The collectors of the bipolar transistors 2604a and 2604b are connected to the emitters of the bipolar transistors 2605a and 2605b, respectively. The collectors of the bipolar transistors 2605a and 2605b are connected to the output terminals OUT1 and OUT2 through the DC cut capacitors 2609a and 2609b, respectively. The emitters of the bipolar transistors 2604a and 2604b are grounded via inductors 2606a and 2606b, respectively. The bias circuit 2610 supplies a bias current to the bases of the bipolar transistors 2604a and 2604b. The bias circuit 2611 supplies a bias current to the bases of the bipolar transistors 2605a and 2605b. The power supply voltage Vcc is supplied to the collectors of bipolar transistors 2605a and 2605b via choke inductors 2912a and 2912b, respectively. With the above configuration, the balanced semiconductor device operates as an amplifier.

  Also in balanced high-frequency device 2601 according to the tenth embodiment of the present invention, by using phase circuits 2603 and 2608, an in-phase signal component can be reduced, and a balanced high-frequency device with excellent balance characteristics can be realized. Can do.

  In the present embodiment, the phase circuit may be configured using a transmission line or three impedance elements. Further, the configuration of the phase circuit is not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit. Further, the number and configuration of inductors and capacitors as impedance elements are not limited to this, and the same effect as the present invention can be obtained as long as the configuration operates as a phase circuit.

  Further, when forming the phase circuit, it may be configured using a transmission line or a chip component on the circuit board, or may be built in a board or package on which a balanced element is mounted. Further, a part of the phase circuit may be configured in a laminated device formed by forming electrode patterns on a plurality of dielectric layers and laminating the dielectric layers. Furthermore, by making the laminated device have other circuit functions, the balanced high-frequency device of the present invention and the laminated device are integrated into a composite device, thereby realizing the multi-function and miniaturization of the balanced high-frequency device. It can be done.

  In this embodiment, the input terminal and the output terminal are both described as balanced. However, either the input terminal or the output terminal may be unbalanced and the other may be balanced.

  In this embodiment, the semiconductor element is configured using four bipolar transistors. However, the present invention is not limited to this.

  Further, although the case where the semiconductor element 2602 is an amplifier has been described in this embodiment, the present invention is not limited to this. The semiconductor element 2602 may be a mixer or an oscillator. In short, the semiconductor element 2602 may be a semiconductor device having a balanced terminal.

(Embodiment 11)
Hereinafter, a balanced high-frequency circuit according to an eleventh embodiment of the present invention will be described with reference to the drawings. FIG. 27 is a block diagram of a balanced high-frequency circuit 2701 using the balanced device of the present invention. In FIG. 27, the transmission signal output from the transmission circuit is transmitted from the antenna 2705 through the transmission amplifier 2702, the transmission filter 2703, and the switch 2704. A reception signal received from the antenna 2705 is input to the reception circuit via the switch 2704, the reception filter 2706, and the reception amplifier 2707. Here, since the transmission amplifier 2702 is a balanced type and the switch 2704 is an unbalanced type, the transmission filter 2703 has an unbalanced-balanced type input / output terminal. Since the reception amplifier 2707 is a balanced type and the switch 2704 is an unbalanced type, the reception filter 2706 has an unbalanced-balanced type input / output terminal.

  By applying the balanced type device of the present invention to the transmission filter 2703 or the reception filter 2706 of the balanced type high frequency circuit 2701 and the balanced type high frequency device of the present invention to the transmission amplifier 2702 or the reception amplifier 2707, the balance characteristic is deteriorated. It is possible to suppress deterioration in modulation accuracy during transmission, and it is possible to suppress deterioration in sensitivity during reception due to deterioration in balance characteristics, thereby realizing a high-performance balanced high-frequency circuit.

  In addition, when the switch 2704 is a balanced type and the transmission amplifier 2702 or the reception amplifier 2707 is an unbalanced type, the same can be obtained by switching the balanced type and unbalanced type input / output terminals of the transmission filter 2703 or the reception filter 2706. An effect is obtained.

  In the balanced high-frequency circuit 2701, the switch 2704 is used as the means for switching between transmission and reception. However, this may be a duplexer.

  In the balanced high-frequency circuit of this embodiment, the phase circuit of the present invention may be formed on a circuit board. For example, in FIG. 27, by forming 2708 and 2709 between balanced transmission lines on the circuit board, deterioration of balance characteristics due to crosstalk of in-phase signal components can be suppressed, and an excellent balanced high-frequency circuit can be realized. is there.

  In the embodiments of the present invention, the balanced high-frequency device has been described using a surface acoustic wave filter or a semiconductor element. However, the present invention is not limited to this and can be applied to other devices that perform a balance operation. is there.

  For devices that handle high-frequency signals, the higher the frequency, the larger the parasitic component, and the in-phase signal component increases due to crosstalk or the like, resulting in greater deterioration of balance characteristics. Therefore, the higher the frequency, the greater the effect of the balanced high-frequency device of the present invention, and the element size of the transmission line and impedance element forming the phase circuit can be reduced.

  The balanced high-frequency circuit according to the present invention has a good balance characteristic and is useful as a balanced high-frequency circuit using a balanced high-frequency device such as a surface acoustic wave filter or a high-frequency amplifier.

Configuration diagram of balanced high-frequency device according to Embodiment 1 of the present invention Explanatory drawing of analysis of cause of balance characteristic deterioration in conventional surface acoustic wave filter Characteristic diagram of balance characteristic analysis in conventional surface acoustic wave filter (a) Amplitude balance characteristic diagram (b) Phase balance characteristic diagram Operational explanatory diagram of balanced high-frequency device in Embodiment 1 of the present invention Configuration diagram of balanced high-frequency device according to Embodiment 2 of the present invention Configuration diagram of balanced high-frequency device according to Embodiment 3 of the present invention Operational explanatory diagram of balanced high-frequency device according to Embodiment 3 of the present invention Configuration diagram of balanced high-frequency device in embodiment 4 of the present invention (A) Operation explanatory diagram of balanced high-frequency device in embodiment 4 of the present invention (b) Diagram showing equivalent circuit of phase circuit regarding differential signal component in embodiment 4 of the present invention (c) Implementation of the present invention The figure which shows the equivalent circuit of the phase circuit regarding the in-phase signal component in Embodiment 4 (A) Operation explanatory diagram of balanced high-frequency device in embodiment 4 of the present invention (b) Diagram showing equivalent circuit of phase circuit regarding differential signal component in embodiment 4 of the present invention (c) Implementation of the present invention The figure which shows the equivalent circuit of the phase circuit regarding the in-phase signal component in Embodiment 4 Configuration diagram of balanced high-frequency device according to Embodiment 5 of the present invention (A) Operation explanatory diagram of balanced high-frequency device in embodiment 5 of the present invention (b) Diagram showing equivalent circuit of phase circuit regarding differential signal component in embodiment 5 of the present invention (c) Implementation of the present invention The figure which shows the equivalent circuit of the phase circuit regarding the in-phase signal component in Embodiment 5 (A) Operation explanatory diagram of balanced high-frequency device in embodiment 5 of the present invention (b) Diagram showing equivalent circuit of phase circuit regarding differential signal component in embodiment 5 of the present invention (c) Implementation of the present invention The figure which shows the equivalent circuit of the phase circuit regarding the in-phase signal component in Embodiment 5 Configuration diagram of balanced high-frequency device according to Embodiment 6 of the present invention (A) Passing characteristic diagram of balanced high-frequency device when using phase circuit 603 (b) Amplitude balance characteristic diagram of balanced high-frequency device when using phase circuit 603 (c) When using phase circuit 603 Phase balance characteristics diagram of balanced high-frequency devices (A) Amplitude balance characteristic diagram of balanced high-frequency device when phase circuit 603 is used (b) Phase balance characteristic diagram of balanced high-frequency device when phase circuit 603 is used (A) Passing characteristic diagram of balanced high frequency device when using phase circuit 901 (b) Amplitude balance characteristic diagram of balanced high frequency device when using phase circuit 901 (c) When using phase circuit 901 Phase balance characteristics diagram of balanced high-frequency devices (A) Amplitude balance characteristic diagram of balanced high-frequency device when phase circuit 901 is used (b) Phase balance characteristic diagram of balanced high-frequency device when phase circuit 901 is used (A) Passing characteristic diagram of balanced high-frequency device when using phase circuit 1001 (b) Amplitude balance characteristic diagram of balanced high-frequency device when using phase circuit 1001 (c) When using phase circuit 1001 Phase balance characteristics diagram of balanced high-frequency devices (A) Amplitude balance characteristic diagram of balanced high frequency device when phase circuit 1001 is used (b) Phase balance characteristic diagram of balanced high frequency device when phase circuit 1001 is used (A) Impedance characteristic diagram when using phase circuit 601 (b) Impedance characteristic diagram when using phase circuit 2201 Configuration diagram including matching circuit in phase circuit (A) Configuration diagram of balanced high-frequency device according to embodiment 7 of the present invention (b) Configuration diagram of balanced high-frequency device having phase circuit including matching circuit Configuration diagram of balanced high-frequency device according to embodiment 8 of the present invention Configuration diagram of balanced high-frequency device in embodiment 9 of the present invention Configuration diagram of balanced high-frequency device in embodiment 10 of the present invention Configuration diagram of balanced high-frequency circuit according to Embodiment 11 of the present invention Configuration diagram of conventional balanced high-frequency device Configuration diagram including matching circuit of conventional balanced high-frequency device (a) Configuration diagram when matching circuit is one impedance element (b) Configuration diagram when matching circuit is two impedance elements Configuration of conventional surface acoustic wave filter Configuration diagram including matching circuit of conventional surface acoustic wave filter (A) Passing characteristic diagram of conventional surface acoustic wave filter (b) Amplitude balance characteristic diagram of conventional surface acoustic wave filter (c) Phase balance characteristic diagram of conventional surface acoustic wave filter

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Balance type high frequency device 102 Balance type element 103 Phase circuit 201 Surface acoustic wave filter 202 Ideal surface acoustic wave filter 203,204 Capacitance component 501 Balance type high frequency device 502 Balance type element 503,504 Phase circuit 601 Balance type high frequency device 602 Balanced element 603 Phase circuit 604 Transmission line 801 Balanced high frequency device 802 Balanced element 803 Phase circuit 804, 805, 806 Impedance element 901 Phase circuit 902, 903 capacitor 904 inductor 905 Virtual ground point 1001 Phase circuit 1002, 1003 Inductor 1004 Capacitor 1005 Virtual ground point 1101 Balanced high-frequency device 1102 Balanced element 1103 Phase circuit 1104, 1105, 1106 Impedance element 120 1 phase circuit 1202, 1203 inductor 1204 capacitor 1205 connection point 1301 phase circuit 1302, 1303 capacitor 1304 inductor 1305 connection point 1401 balanced high frequency device 1402 surface acoustic wave filter 1403 phase circuit 1404 piezoelectric substrate 1405 first IDT electrode 1406 second IDT electrode 1407 Third IDT electrode 1408 First reflector electrode 1409 Second reflector electrode 1601, 1801, 2001 Maximum value of amplitude balance characteristic degradation of conventional surface acoustic wave filter 1602, 1802, 2002 Conventional elastic surface Minimum value of deterioration of amplitude balance characteristic of wave filter 1603, 1803, 2003 Maximum value of deterioration of phase balance characteristic of conventional surface acoustic wave filter 1604, 1804, 2004 Conventional elasticity table Minimum value of phase balance characteristic degradation of wave filter 2101, 2102 Region indicating passband frequency vicinity 2201 Phase circuit 2202 Capacitor 2301 Balanced high frequency device 2302 Balanced element 2303 Phase circuit 2304, 2305 Capacitor 2306 Inductor 2307 Inductor 2308 as matching circuit Virtual ground point 2309 Synthetic inductor 2401 Balanced high-frequency device 2402 Surface acoustic wave filter 2403 Phase circuit 2404 Piezoelectric substrate 2405 First IDT electrode 2406 Second IDT electrode 2407 Third IDT electrode 2408 First reflector electrode 2409 Second Reflector electrode 2410 first divided IDT electrode 2411 second divided IDT electrode 2501 balanced high-frequency device 2502 surface acoustic wave filter 2503 phase rotation 2504 Piezoelectric substrate 2505 First IDT electrode 2506 Second IDT electrode 2507 Third IDT electrode 2508 First reflector electrode 2509 Second reflector electrode 2601 Balanced high-frequency device 2602 Semiconductor element 2603 Phase circuits 2604a, 2604b, 2605a, 2605b Bipolar transistor 2606a, 2606b Inductor 2607 DC cut capacitor 2608 Bypass capacitor 2609a, 2609b DC cut capacitor 2610, 2611 Bias circuit 2612a, 2612b Choke inductor 2701 Balanced high frequency circuit 2702 Transmit amplifier 2703 Transmit filter 2704 Switch 2705 Antenna 2270 2707 Reception amplifier 2708, 2709 Balanced transmission line 28 1,2901 Balanced high-frequency device 2902, 2904, 2905 Matching circuit 2903 Balanced high-frequency device 3001 Surface acoustic wave filter 3002 Piezoelectric substrate 3003 First IDT electrode 3004 Second IDT electrode 3005 Third IDT electrode 3006 First reflection 3007 2nd reflector electrode 3101 Surface acoustic wave filter 3102 Piezoelectric substrate 3103 1st IDT electrode 3104 2nd IDT electrode 3105 3rd IDT electrode 3106 1st reflector electrode 3107 2nd reflector electrode 3108 First divided IDT electrode 3109 Second divided IDT electrode 3110 Inductor

Claims (3)

A balanced high-frequency circuit connected between a balanced transmission line that connects a filter having a first balanced terminal and a device having a second balanced terminal via the first and second balanced terminals. Because
A balanced input terminal connected to the first balanced terminal;
A balanced output terminal connected to the second balanced terminal;
A phase circuit electrically connected between at least one of the balanced input terminals or between the balanced output terminals;
The phase circuit is a parallel resonant circuit that resonates in parallel with a ground plane with respect to a predetermined frequency with respect to a differential signal component of a signal flowing through the balanced transmission line, and the parallel resonant circuit includes at least three A first reactance element is connected between one of the balanced input terminals or one of the balanced output terminals and a ground plane, and the other of the balanced input terminals or the A second reactance element is connected between the other of the balanced output terminals and the ground plane, and a third reactance element is connected between the balanced input terminals or between the balanced output terminals, The imaginary part of the impedance of the first and second reactance elements and the imaginary part of the impedance of the third reactance element are different in polarity, and the in-phase signal component of the signal is Then, the impedance of one of the balanced input terminals or one of the balanced output terminals and the ground plane, and the impedance of the other of the balanced input terminals or the other of the balanced output terminals and the ground plane are: A balanced high-frequency circuit that is less than twice the characteristic impedance of the first balanced terminal or the second balanced terminal and reduces the in-phase signal component of the signal.   2. The balanced high-frequency circuit according to claim 1, wherein an impedance of the in-phase signal component of the signal with respect to a ground plane is 0.5 times or less of a characteristic impedance of the first balanced terminal or the second balanced terminal. A balanced high-frequency circuit connected between a balanced transmission line that connects a filter having a first balanced terminal and a device having a second balanced terminal via the first and second balanced terminals. Because
A balanced input terminal connected to the first balanced terminal;
A balanced output terminal connected to the second balanced terminal;
A phase circuit electrically connected between at least one of the balanced input terminals or between the balanced output terminals;
The phase circuit is a series resonance circuit that resonates in series with a ground plane with respect to a predetermined frequency with respect to an in-phase signal component of a signal flowing through the balanced transmission line, and the series resonance circuit includes at least three series resonance circuits. The first and second reactance elements are connected between one of the balanced input terminals or one of the balanced output terminals and a ground plane. A third reactance element is connected between the connection point of the second reactance element and the ground plane, and the imaginary part of the impedance of the first and second reactance elements and the impedance of the third reactance element With respect to the differential signal component of the signal, a virtual ground plane is formed between the first and second reactance elements, the polarity of the imaginary part is different, and the first and second The impedance of one of the balanced input terminals or one of the balanced output terminals and the virtual ground plane and the other of the balanced input terminals or the balanced output terminal The balanced high-frequency circuit is configured to reduce the in-phase signal component of the signal by the series resonance circuit, in which the impedance between the other of the two and the ground plane is set large.

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