JP2012060275A - High-frequency power amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency power amplifier capable of reducing a mounting area by decreasing the number of components that are used, and suppressing passage loss caused by passing a switch of signal.SOLUTION: A high-frequency power amplifier 21 includes matching circuits 23, 25, 26, and 27 and at least one high-frequency power amplification element 24. The matching circuit includes a circuit in which a first matching line 41 and a second matching line 42, with two reactance elements 37, 38, 39, and 40 being connected in series, are connected in parallel, and a switch 43 which is connected to a ground and between the reactance elements of the first matching line as well as between the reactance elements of the second matching line, for selecting one of them. By switching the switch, a signal is propagated to either the first matching line or the second matching line, with the other connected to the ground.

Description

  The present invention relates to a high-frequency power amplifier used for a transmission unit of a wireless terminal, and more particularly to a high-frequency power amplifier capable of amplifying power in a plurality of frequency bands.

  First, a conventional multiband high frequency power amplifier will be described with reference to FIG. Here, the band refers to a continuous frequency band, and the multiband high-frequency power amplifier refers to a high-frequency power amplifier capable of amplifying power in a plurality of continuous frequency bands. In addition, when a plurality of frequency bands are continuous, the high-frequency power amplifier can be widened.

  FIG. 6 shows a conventional multiband high-frequency power amplifier that performs power amplification on two different bands, with two different frequency bands being A band and B band, respectively.

  In FIG. 6, 2 is an input terminal of the high frequency power amplifier 1, 3 is an input side switch, 4 is an A band power amplifier, 5 is a B band power amplifier, 6 is an output side switch, and 7 is the high frequency power amplifier 1. Output terminals are shown. The input terminal 2 is connected to a common terminal 3a of the input side switch 3, and the A-band power amplifier 4 is connected to a switching terminal 3b of the input side switch 3 and a switching terminal 6b of the output side switch 6. The band power amplifier 5 is connected to the switching terminal 3 c of the input side switch 3 and the switching terminal 6 c of the output side switch 6, and the output terminal 7 is connected to the common terminal 6 a of the output side switch 6. A high frequency power amplifier 1 is configured. The A-band power amplifier 4 and the B-band power amplifier 5 are optimized for power amplification in different bands.

  In the high-frequency power amplifier 1 having the above configuration, the input side switch 3 is switched to connect the common terminal 3a and the switching terminal 3b, and the output side switch 6 is switched to switch the common terminal 6a and the switching terminal 6b. , The signal input from the input terminal 2 is amplified by the A-band power amplifier 4 and output from the output terminal 7. The input terminal 2 is switched by switching the input side switch 3 to connect the common terminal 3a and the switching terminal 3c, and the output side switch 6 is switched to connect the common terminal 6a and the switching terminal 6c. Is amplified by the B-band power amplifier 5 and output from the output terminal 7.

  As described above, in the conventional high-frequency power amplifier 1, the A-band power amplifier 4 and the B-band power amplifier optimized for each band by switching the input side switch 3 and the output side switch 6. 5 is selected to realize multiband.

  FIG. 7 shows another conventional example of the high-frequency power amplifier 1. In this conventional example, only the matching circuit optimized for each band is switched instead of selecting the power amplifier optimized for each band. Thus, the high-frequency power amplifier 1 is made multiband.

  In FIG. 7, 8 is an input terminal of the high-frequency power amplifier 1, 9 is a matching circuit, 11 is a high-frequency power amplifying element, 12 is a matching circuit input side switch, 13 is an A-band matching circuit, 14 is a B-band matching circuit, Reference numeral 15 denotes a matching circuit output side switch, and 16 denotes an output terminal of the high-frequency power amplifier 1. The input terminal 8 is connected to the common terminal 12a of the matching circuit input side switch 12 via the matching circuit 9 and the high-frequency power amplifying element 11, and the A-band matching circuit 13 is connected to the matching circuit input side switch 12. The B-band matching circuit 14 is connected to the switching terminal 12b and the switching terminal 15c of the matching circuit output side switch 15, and is connected to the switching terminal 12b of the matching circuit output side switch 12 and the switching terminal 15c of the matching circuit output side switch 15. The high frequency power amplifier 1 is configured by connecting the output terminal 16 to the common terminal 15a of the matching circuit output side switch 15.

  In the other conventional example of FIG. 7, as in the conventional example of FIG. 6, the matching circuit input side switch 12 and the matching circuit output side switch 15 are switched to input from the input terminal 8 by the high frequency power amplifying element 11. The amplified signal is matched by passing through one of the A-band matching circuit 13 and the B-band matching circuit 14 and is output from the output terminal 16.

  Since the A-band matching circuit 13 and the B-band matching circuit 14 are optimized for different bands, respectively, the A-band matching circuit 13 and the B-band matching circuit according to the frequency. Multibanding is realized by selecting one of the matching circuits 14.

  However, the conventional multiband high-frequency power amplifier requires the same number of power amplifiers and matching circuits as the required number of bands, and similarly requires a plurality of switches, which increases the mounting area. In addition, since a switch exists on the signal propagation path, a power passing loss occurs when the signal passes through the switch.

JP 2010-41634 A

  In view of such a situation, the present invention provides a high-frequency power amplifier that reduces the number of parts used and reduces the mounting area and suppresses the passage loss due to signal passing through a switch.

  The present invention is a high-frequency power amplifier having a matching circuit and at least one high-frequency power amplifying element, wherein the matching circuit includes a first matching line and a second matching line in which two reactance elements are connected in series. And a switch connected to the ground between the reactance elements of the first matching line and between the reactance elements of the second matching line, and capable of selecting one of them. By switching the switch, a signal is propagated to one of the first matching line and the second matching line, and the other is related to a high-frequency power amplifier that connects the other to the ground.

  According to the present invention, a high frequency power amplifier having a matching circuit and at least one or more high frequency power amplifying elements, the matching circuit includes a first matching line in which two reactance elements are connected in series, and a second matching line. A circuit in which matching lines are connected in parallel, and a switch that is connected to the ground between the reactance elements of the first matching line and between the reactance elements of the second matching line and is selectable. By switching the switch, the signal is propagated to one of the first matching line and the second matching line, and the other is connected to the ground, so that the switch exists on the signal propagation path. Without passing through the switch, and it is necessary to prepare a plurality of matching circuits to change the signal propagation path. Ku, exhibits an excellent effect that can reduce the mounting area by reducing the number of parts.

1 is a circuit diagram of a high-frequency power amplifier according to a first embodiment of the present invention. (A) is an equivalent circuit diagram when switching to the A-band matching circuit in the first embodiment, and (B) is a diagram when switching to the B-band matching circuit in the first embodiment. It is an equivalent circuit diagram. It is a figure which shows the simulation result at the time of simulating a power gain using the circuit of FIG. It is a circuit diagram of the high frequency power amplifier in the 2nd Example of this invention. It is a circuit diagram of the high frequency power amplifier in the 3rd Example of this invention. It is a circuit diagram which shows the prior art example of a multiband high frequency power amplifier. It is a circuit diagram which shows the other conventional example of a multiband high frequency power amplifier.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, a high-frequency power amplifier according to a first embodiment of the present invention will be described.

  In FIG. 1, 21 is a high-frequency power amplifier, 22 is an input terminal of the high-frequency power amplifier 21, 23 is a first matching circuit that performs primary matching, and 24 is a high-frequency power that amplifies a signal input from the input terminal 22. An amplifying element, 25 is a second matching circuit that performs second-order matching, 26 is a third matching circuit unit that performs third-order matching by appropriately selecting two types of matching circuits, and 27 is a fourth matching circuit that performs fourth-order matching. A matching circuit 28 indicates an output terminal of the high-frequency power amplifier 21, and terminals 29 and 31 for applying power for amplification are connected to the input and output of the high-frequency power amplifier 24, respectively. .

  The first matching circuit 23 includes a capacitor 32 and an inductor 33 connected in series, and a capacitor 34 connected to a line between the capacitor 32 and the inductor 33 and the ground. The second matching circuit 25 has an inductor 35 and a capacitor 36 connected to the ground.

  The third matching circuit section 26 includes capacitors 37, 38, 39, and 40, which are reactance elements, and a switch 43, and a first matching line 41 is configured in which the capacitors 37 and 38 are connected in series. A second matching line 42 in which the capacitors 39 and 40 are connected in series is formed, and the first matching line 41 and the second matching line 42 are connected in parallel. Further, switching terminals 43b and 43c of a switch 43 are connected between the capacitors 37 and 38 of the first matching line 41 and between the capacitors 39 and 40 of the second matching line 42, respectively. The common terminal 43a is connected to the ground, and by switching the switch 43, it is possible to appropriately select which of the first matching line 41 and the second matching line 42 is used for the third matching. It has become.

  The fourth matching circuit 27 includes a capacitor 44 and an inductor 45 connected to the ground.

  In the following, the first matching line 41 connected to the second matching circuit 25 and the fourth matching circuit 27 and the second matching line 42 connected to the ground are included. The matching circuit is an A-band matching circuit 46, the second matching line 42 connected to the second matching circuit 25 and the fourth matching circuit 27, and the first matching line connected to the ground. 41 is a B-band matching circuit 47.

  As the switch 43, a mechanical relay, an electronic switch using an FET (Field-Effect Transistor), a PIN diode, or the like can be used.

  In the high-frequency power amplifier 21 configured as described above, when the switch 43 is switched and the switching terminal 43c is connected to the common terminal 43a, the capacitors 37 and 38 are connected to the second matching circuit 25 and the second matching circuit 25a. 4 in which the capacitors 39 and 40 are connected to the ground via the switch 43, that is, the third matching circuit section 26 becomes the A-band matching circuit 46, and is an equivalent circuit diagram. Is as shown in FIG.

  Accordingly, the signal input from the input terminal 22 is primarily matched by the first matching circuit 23, amplified by the high frequency power amplifier 24, and secondarily matched by the second matching circuit 25. Third-order matching is performed by the A-band matching circuit 46 and fourth-order matching is performed by the fourth matching circuit 27, and then output from the output terminal 28.

  When the switch 43 is switched and the switching terminal 43b is connected to the common terminal 43a, the capacitors 39 and 40 are connected to the second matching circuit 25 and the fourth matching circuit 27, and A state in which the capacitors 37 and 38 are connected to the ground via the switch 43, that is, the third matching circuit unit 26 becomes the B-band matching circuit 47, and an equivalent circuit diagram is as shown in FIG.

  Accordingly, the signal input from the input terminal 22 is primarily matched by the first matching circuit 23, amplified by the high frequency power amplifier 24, and secondarily matched by the second matching circuit 25. Third-order matching is performed by the B-band matching circuit 47 and fourth-order matching is performed by the fourth matching circuit 27, and then output from the output terminal 28.

  As described above, the switch 43 is placed on the signal propagation path in both cases where the third-order matching is performed by the A-band matching circuit 46 and the third-order matching is performed by the B-band matching circuit 47. Therefore, it is possible to suppress a passage loss caused by a signal passing through the switch 43.

  Further, since the A-band matching circuit 46 and the B-band matching circuit 47 can be switched only by the switch 43, the high-frequency power can be set by setting the frequency characteristics of the two matching circuits differently. Multibanding of the amplifier 21 can be realized.

  Further, since it is not necessary to prepare a plurality of matching circuits in order to make the high-frequency power amplifier 21 multiband, the high-frequency power amplifier 21 can be realized with only one switch. Therefore, the high-frequency power amplifier 21 is reduced by reducing the number of parts used. The mounting area can be reduced, and the manufacturing cost can be reduced.

  FIG. 3 is a simulation result when a power gain simulation is performed using the circuit diagram of FIG. In the figure, the horizontal axis indicates the frequency and the vertical axis indicates the power gain, the solid line 48 indicates the simulation result when the A-band matching circuit 46 is used, and the broken line 49 indicates when the B-band matching circuit 47 is used. The simulation results are as follows.

  In this simulation, the capacitor 32 is 220 pF, the inductor 33 is 8.2 nH, the capacitor 34 is 9 pF, the inductor 35 is 5.6 nH, the capacitor 36 is 27 pF, the capacitor 37 is 9 pF, and the capacitor 38 is 39 pF, the capacitor 39 is 27 pF, the capacitor 40 is 33 pF, the capacitor 44 is 220 pF, the inductor 45 is 3.6 nH, and an FET is used as the high-frequency power amplifying element 24. The terminals 29 and 31 for power supply are connected.

  In the high-frequency power amplifier 21 configured as described above, for example, consider a case where a power gain of 10 dB or more is required. When the switch 43 is switched and the common terminal 43a is connected to the switching terminal 43c, a power gain of 10 dB or more can be obtained in the frequency band of 360 MHz to 430 MHz from FIG. When the switch 43 is switched and the common terminal 43a is connected to the switching terminal 43b, a power gain of 10 dB or more can be obtained in the frequency band of 300 MHz to 370 MHz from FIG.

  Therefore, by switching the switch 43, a power gain of 10 dB or more can be obtained in two frequency bands, so that the high-frequency power amplifier 21 can be multibanded, and the two frequency bands are continuous. Specifically, a high frequency power amplifier capable of amplifying a desired power from 300 MHz to 430 MHz can be obtained.

  Next, a second embodiment of the present invention will be described with reference to FIG. 4 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the second embodiment, instead of the capacitors 37, 38, 39, and 40 in the first embodiment, inductors 50, 51, 52, and 53, which are reactance elements, are used. A capacitor 54 is provided on the line between the second matching circuit 25 and other configurations are the same as those in the first embodiment. Note that the inductors 50 and 51 connected in series constitute a first matching line 41, and the inductors 52 and 53 connected in series constitute a second matching line 42. The first matching line 41 and the second matching line 42 are connected in parallel.

  In the second embodiment, the capacitor 54 is provided, for example, by switching the switch 43 to connect the common terminal 43a to the switching terminal 43c, and is connected to the second matching circuit 25 and the fourth matching circuit 27. In addition, when a matching circuit is configured by the first matching line 41 and the second matching line 42 connected to the ground, the DC component of the power input from the terminal 31 is changed to the second matching line. This is to prevent connection to the ground through the circuit 25, the inductor 52, and the switch 43.

  Also, when the switch 43 is switched and the common terminal 43a is connected to the switching terminal 43b, the DC component of the power input from the terminal 31 is converted into the second matching circuit 25, the inductor 50, the Connection to the ground through the switch 43 can be prevented by the capacitor 54.

  In the case of the second embodiment, the matching circuit configured in the third matching circuit unit 26 includes the inductors 50 and 51 having a large inductance component or the inductors 52 and 53 connected in series on the signal propagation path. Therefore, a large inductance component can be obtained. Therefore, it is possible to obtain a matching circuit suitable for amplification in a low frequency region where a large inductance component such as a VHF (Very High Frequency) band needs to be connected in series.

  Further, by setting the two matching circuits obtained by switching the switch 43 so as to have different frequency characteristics, the multi-band configuration of the high-frequency power amplifier 21 can be realized.

  The capacitor 54 may be omitted when a capacitor is provided on the signal propagation path in the second matching circuit 25. The capacitor 54 may be provided between the second matching circuit 25 and the third matching circuit unit 26.

  Next, a third embodiment will be described with reference to FIG. 5 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the third embodiment, a part of the capacitors 37, 38, 39, and 40 (capacitors 38 and 40 in the figure) in the first embodiment are changed to inductors 55 and 56 that are reactance elements. The capacitor 37 and the inductor 55 connected in series constitute a first matching line 41, and the capacitor 39 and the inductor 56 connected in series constitute a second matching line 42. The first matching line 41 and the second matching line 42 are connected in parallel.

  In the case of the third embodiment, similarly to the first embodiment and the second embodiment, two types of matching circuits are configured in the third matching circuit section 26 by switching the switch 43, and 2 By setting the types of matching circuits so that the frequency characteristics are different, it is possible to realize a multiband configuration of the high-frequency power amplifier 21.

  In the third embodiment, the capacitors 38 and 40 in the first embodiment are changed to the inductors 55 and 56, but it goes without saying that any capacitor may be changed to an inductor. Absent.

  In the first to third embodiments, the high-frequency power amplifying element 24 is described as having a single stage, but the high-frequency power amplifying element 24 may be configured in two or more stages. The one matching circuit 23, the second matching circuit 25, and the fourth matching circuit 27 may be matching circuits having different configurations.

(Appendix)
The present invention includes the following embodiments.

  (Appendix 1) A high-frequency power amplifier having a matching circuit and at least one or more high-frequency power amplifying elements, wherein the matching circuit includes a first matching line and a second matching line in which two reactance elements are connected in series. And a switch connected to the ground between the reactance elements of the first matching line and between the reactance elements of the second matching line, and capable of selecting one of them. A high-frequency power amplifier, wherein a signal is propagated to one of the first matching line and the second matching line by switching the switch, and the other is connected to the ground.

  (Supplementary note 2) The high frequency power amplifier according to supplementary note 1, wherein the reactance element is a capacitor.

  (Additional remark 3) The high frequency power amplifier of Additional remark 1 whose said reactance element is an inductor.

  (Supplementary note 4) The high-frequency power amplifier according to supplementary note 1, wherein the reactance element is a capacitor and an inductor.

DESCRIPTION OF SYMBOLS 21 High frequency power amplifier 23 1st matching circuit 24 High frequency power amplification element 25 2nd matching circuit 26 3rd matching circuit part 27 4th matching circuit 37-40 Capacitor 41 1st matching line 42 2nd matching line 43 Switch 46 A-band matching circuit 47 B-band matching circuit 50 to 53 Inductors 55 and 56 Inductors

Claims (1)

  A high-frequency power amplifier having a matching circuit and at least one or more high-frequency power amplifying elements, wherein the matching circuit includes a first matching line in which two reactance elements are connected in series and a second matching line connected in parallel. A switch connected to the ground between the reactance elements of the first matching line and between the reactance elements of the second matching line and to the ground, and switches the switch. Thus, a signal is propagated to one of the first matching line and the second matching line, and the other is connected to the ground.

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