JP2013125976A - Rf power amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a terminal impedance of termination action when terminating a plurality of second harmonics by means of a common second harmonic frequency termination circuit.SOLUTION: An RF power amplifier includes an RF amplification circuit 100 and a second harmonic termination circuit 102. An RF input signal having first and second frequency bands is supplied to an input of the RF amplification circuit 100. The second harmonic termination circuit 102 includes a capacitance C5 and an inductor L3 connected in series between an output of the RF amplification circuit 100 and a ground potential GND, and has a series resonance frequency fthereof set at a set frequency between the lowest frequency of second harmonic components of the first frequency band and the highest frequency of second harmonic components of the second frequency band. The capacitance C5 has a capacitance value set such that a series connection impedance of the second harmonic termination circuit 102 is smaller than a predetermined value at the lowest frequency and at the highest frequency. A low pass filter type output matching circuit 101 provides a bypass to the ground potential GND for the second harmonic components of the second frequency band.

Description

  The present invention relates to an RF power amplifier, and in particular, performs a termination operation of a plurality of second harmonics of a plurality of transmission RF frequencies of an RF transmission output signal generated by the RF power amplifier by a common second harmonic frequency termination circuit. In particular, the present invention relates to a technique effective in reducing the termination impedance of the termination operation of the common second harmonic frequency termination circuit.

  Mobile phones that enable mobile communications have progressed from the second generation (2G), called the GSM system, to the W-CDMA system and the third generation (3G) of CDMA2000, and will appear in the future as the third generation (3G). The LTE system is progressing as a system between the fourth generation (4G). GSM is an abbreviation for Global System for Mobile Communication. W-CDMA is an abbreviation for Wideband Code Multiplex Access. Furthermore, LTE is an abbreviation for Long Term Evolution.

  The second generation (2G) GSM system includes four systems: GSM850, GSM900, DCS1800, and PCS1900. The GSM850 system is a system that is mainly used in North America, and a radio frequency (RF) of 824 to 849 MHz is used for transmission (uplink) from a mobile phone terminal to a base station. The GSM900 system is mainly used in Asia, Africa, Oceania, Europe, and Latin America, and a radio frequency (RF) of 880 to 915 MHz is used for transmission (uplink) from a mobile phone terminal to a base station. . The DCS1800 system is also widely used mainly in Asia, Africa, Oceania, Europe, and Latin America. Radio frequency (RF) of 1710 to 1785 MHz is used for transmission (uplink) from a mobile phone terminal to a base station. The Furthermore, the PCS1900 system is a system that is mainly used in North America, Central and South America, and a radio frequency (RF) of 1850 to 1910 MHz is used for transmission (uplink) from the mobile phone terminal to the base station. In general, the GSM850 system and the GSM900 system are called GSM system low band, and the DCS1800 system and the PCS1900 system are called GSM system highband.

  According to the LTE technical specifications created by 3GPP, an extremely large number of frequency bands can be used. Typical examples are band 1, band 2, band 3, band 5, and band 8. A radio frequency (RF) of 1920 to 1980 MHz is used for transmission (uplink) from the mobile telephone terminal in band 1 to the base station. A radio frequency (RF) of 1850 to 1910 MHz is used for transmission (uplink) from the mobile phone terminal in band 2 to the base station. A radio frequency (RF) of 1710 to 1785 MHz is used for transmission (uplink) from the mobile phone terminal in band 3 to the base station. A radio frequency (RF) of 824 to 915 MHz is used for transmission (uplink) from the mobile phone terminal in band 5 to the base station. A radio frequency (RF) of 880 to 915 MHz is used for transmission (uplink) from the mobile phone terminal in band 8 to the base station. 3GPP is an abbreviation for Third Generation Partnership Project.

  On the other hand, the following Patent Document 1 describes that the termination of the second harmonic frequency is an important element in order to improve the efficiency of the RF power amplifier, and an RF transmission signal having a single transmission RF frequency is described. In the single-band RF power amplifier capable of amplifying, it is described that an even harmonic resonator constituted by a series connection of one inductor and one capacitor is connected between the output terminal of the amplification transistor and the ground potential. Has been. This even harmonic resonator is said to exhibit zero impedance with respect to the second harmonic.

  Further, in Patent Document 1 below, a dual-band RF power amplifier capable of amplifying an RF transmission signal having a plurality of transmission RF frequencies includes a secondary including two inductors, two capacitors, and one switch. It is described that a harmonic frequency termination circuit is connected between an output terminal of an amplification transistor and a ground potential. The first inductor of the second harmonic frequency termination circuit and the first series connection of the first capacitor are connected between the output terminal of the amplification transistor and the ground potential, and the second inductor of the second harmonic frequency termination circuit A second series connection of the second capacitor and one switch is connected between the output terminal of the amplification transistor and the ground potential. In the high band frequency, the first series connection including the first inductor and the first capacitor exhibits low impedance with respect to the second harmonic of the high band frequency. At the low band frequency, the diode as one switch is turned on, and the second series connection including the second inductor, the second capacitor, and the one switch is connected to the second harmonic of the low band frequency. It shows a low impedance.

US Pat. No. 6,236,274 B1 Specification

  Prior to the present invention, the present inventors have made it possible to amplify an RF transmission signal having multiband transmission RF frequencies of LTE band 1, band 2, band 3, band 5 and band 8. Engaged in the development of RF power amplifiers. In the LTE system described above, the transmission RF frequency of band 1 is 1920 to 1980 MH, the transmission RF frequency of band 2 is 1850 to 1910 MHz, and the transmission RF frequency of band 3 is 1710 to 1785 MHz. Furthermore, in the LTE system, the transmission RF frequency of band 5 is 824 to 849 MHz, and the transmission RF frequency of band 8 is 880 to 915 MHz. In the present specification, LTE band 1, band 2 and band 3 are referred to as LTE high band, and LTE band 5 and band 8 are referred to as LTE low band.

  On the other hand, prior to the present invention, the present inventors have made various transmission RF frequencies of LTE band 1, band 2, band 3, band 5, and band 8 and various types of second generation (2G) GSM systems. The transmission RF frequency of the system was compared. As a result, the following matters were found.

  That is, the transmission RF frequency (1850 to 1910 MHz) of Band 2 of the LTE system matches the transmission RF frequency (1850 to 1910 MHz) of the PCS1900 system of the GSM system. Further, the transmission RF frequency (1710 to 1785 MHz) of the LTE system band 3 matches the transmission RF frequency (1710 to 1785 MHz) of the GSM DCS1800 system. Further, the transmission RF frequency (824 to 849 MHz) of the band 5 of the LTE system matches the transmission RF frequency (824 to 849 MHz) of the GSM 850 system of the GSM system. Furthermore, the transmission RF frequency (880 to 915 MHz) of the LTE band 8 matches the transmission RF frequency (880 to 915 MHz) of the GSM 900 system. However, the transmission RF frequency (1920 to 1980 MHz) of LTE system band 1 is an extremely high frequency that does not exist in any of the GSM systems.

  On the other hand, prior to the present invention, the present inventors calculated the second harmonics of the transmission RF frequencies of LTE band 1, band 2, band 3, band 5, and band 8 multiband as follows: .

Band 1 second harmonic: 3840-3960 MHz
Band 2 second harmonic: 3700-3820 MHz
Band 3 second harmonic: 3420-3570 MHz
Band 5 second harmonic: 1648 to 1698 MHz
Band 8 second harmonic: 1760-1830 MHz
On the other hand, in the development of the multiband RF power amplifier by the present inventors prior to the present invention, a dual amplifier comprising a first multistage RF amplifier circuit on the first path and a second multistage RF amplifier circuit on the second path・ Architecture was adopted.

  That is, the first multi-stage RF amplifier circuit on the first path performs the amplification of the high band transmission frequency having the LTE high band transmission RF frequency (1710 to 1980 MHz) of the LTE band 1, band 2 and band 3 On the other hand, the second multi-stage RF amplifier circuit on the second path performs amplification of the low band transmission frequency having the LTE low band transmission RF frequency (824 to 915 MHz) of the LTE band 5 and the band 8. . Accordingly, the first multi-stage RF amplifier circuit on the first path performs amplification of the high band transmission frequency having the triple band transmission RF frequency which is the LTE high band of the LTE band 1, band 2 and band 3. The second multi-stage RF amplifier circuit on the second path performs amplification of the low band transmission frequency having the dual band transmission RF frequency which is the LTE system band 5 and the LTE system low band of the LTE system.

  On the other hand, the first second harmonic frequency termination circuit required for the first multistage RF amplifier circuit on the first path needs to perform the second harmonic termination operation of the triple-band transmission RF frequency described above, The second second harmonic frequency termination circuit necessary for the second multistage RF amplifier circuit on the second path also needs to execute the second harmonic termination operation of the dual-band transmission RF frequency described above.

  In order for the first second harmonic frequency termination circuit to perform the second harmonic termination operation of the triple-band transmission RF frequency described above, the second harmonic including a plurality of series connections described in Patent Document 1 above. Prior to the present invention, the present inventors examined the use of a wave frequency termination circuit. However, when this method is adopted, three series connections are required for the first second harmonic frequency termination circuit, and the number of passive components in the first second harmonic frequency termination circuit increases. This problem has been clarified by the study by the present inventors prior to the present invention. Furthermore, when this method is adopted, the insertion loss caused by one switch included in the second harmonic frequency termination circuit cannot be ignored, and power added efficiency (PAE) is added. The problem of lowering the density was also clarified by studies by the present inventors prior to the present invention.

  Therefore, in order to solve these problems, the second harmonic frequency termination circuit is used in order for the first second harmonic frequency termination circuit to perform the second harmonic termination operation of the triple-band transmission RF frequency described above. Prior to the present invention, the present inventors studied a method in which the above-described configuration is configured only by a first series connection including a first inductor and a first capacitor. However, when this method is adopted, the first series connection that constitutes the second harmonic frequency termination circuit uses all of the triple-band transmission RF frequencies of the above-described LTE band 1, band 2, and band 3. It is necessary to perform the second harmonic termination operation.

  Therefore, the first series connection constituting the second harmonic frequency termination circuit is 540 MHz (= 3960 MHz-3420 MHz) from the lowest frequency 3420 MHz of the second harmonic of the band 3 to the highest frequency 3960 MHz of the second harmonic of the band 1. Therefore, it is necessary to perform termination operation of all second harmonics having an extremely wide frequency band. On the other hand, the frequency band of all the second harmonics of the dual band transmission RF frequency of the band 5 and the band 8 of the LTE system described above is from the lowest frequency 1648 MHz of the second harmonic of the band 5 to the second harmonic of the band 8. It is a relatively narrow frequency band of 170 MHz (= 1824 MHz-1648 MHz) up to a maximum wave frequency of 1824 MHz.

  However, as a result of the study by the present inventors prior to the present invention, all having an extremely wide frequency band of 540 MHz from the lowest frequency 3420 MHz of the second harmonic of band 3 to the highest frequency 3960 MHz of the second harmonic of band 1 It was revealed that it is difficult to set the termination impedance of the termination operation to a sufficiently low value when performing the termination operation of the second harmonic. By saying that the termination impedance of the termination operation of the second harmonic frequency termination circuit is high, it is impossible to sufficiently attenuate the second harmonic frequency.

  On the other hand, when the termination impedance of the termination operation of the second harmonic frequency termination circuit is excessively low as a result of studies by the inventors prior to the present invention, the power added efficiency (PAE) characteristic is Although it was good, the problem that the distortion characteristic called Adjacent Channel Leakage Ratio (ACLR) deteriorated was clarified.

  The present invention has been made as a result of the examination by the present inventors prior to the present invention as described above.

  Accordingly, an object of the present invention is to perform a termination operation of a plurality of second harmonics of a plurality of transmission RF frequencies of an RF transmission output signal generated by an RF power amplifier by a common second harmonic frequency termination circuit. In this case, the termination impedance of the termination operation of the common second harmonic frequency termination circuit is to be reduced.

  Another object of the present invention is to perform a termination operation of a plurality of second harmonics of a plurality of transmission RF frequencies of an RF transmission output signal generated by an RF power amplifier by a common second harmonic frequency termination circuit. It is to improve both power added efficiency (PAE) and adjacent channel leakage ratio (ACLR) characteristics when executing.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  A typical one of the inventions disclosed in the present application will be briefly described as follows.

  That is, a typical embodiment of the present invention is an RF power amplifier including an RF amplifier circuit (100) and a second harmonic termination circuit (102).

  When an RF input signal having a plurality of RF frequency bands is supplied to an input terminal of the RF amplifier circuit (100), the RF amplifier circuit (100) performs power amplification of the RF input signal.

  The plurality of RF frequency bands include at least a first frequency band (band 3) having a predetermined frequency band and a second frequency band (band 1) having a frequency band having a frequency higher than the predetermined frequency band. .

  The second harmonic termination circuit (102) includes a capacitor (C5) and an inductor (L3) connected in series between the output terminal of the RF amplifier circuit (100) and a ground potential (GND).

The series resonance frequency (f ₀ ) determined by the capacitance value of the capacitor (C5) of the second harmonic termination circuit (102) and the inductance value of the inductor (L3) is substantially equal to the first frequency band. The lowest frequency (3420 Hz) of the first second harmonic component having twice the frequency and the highest frequency (3960 Hz) of the second second harmonic component having a frequency substantially twice that of the second frequency band. Is set to a set frequency (3495 Hz).

The capacitance (C5) of the second harmonic termination circuit (102) at the lowest frequency, the first series connection impedance (Z _{2HD_L} ) of the inductor (L3), and the second harmonic termination circuit at the highest frequency The capacitance value of the capacitor (C5) is set so that the second series connection impedance (Z _{2HD_H} ) of the capacitor (C5) of (102) and the inductor (L3) is smaller than a predetermined value. (See FIG. 1).

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, according to the present invention, when the second harmonic termination operation of the plurality of transmission RF frequencies of the RF transmission output signal generated by the RF power amplifier is performed by the common second harmonic frequency termination circuit. The termination impedance of the termination operation of the common second harmonic frequency termination circuit can be reduced.

FIG. 1 is a diagram showing a basic configuration of an RF power amplifier according to Embodiment 1 of the present invention. FIG. 2 is a diagram showing a specific configuration of the RF power amplifier according to the first embodiment of the present invention shown in FIG. FIG. 3 shows the series resonant impedance of the second harmonic frequency termination circuit 102 and the capacitance C5 of the second harmonic frequency termination circuit 102 of the RF power amplifier according to the first embodiment of the present invention shown in FIGS. It is a figure which shows the relationship with a capacitance value. FIG. 4 is a diagram showing a Smith chart for explaining the characteristics of the second harmonic frequency termination circuit 102 of the RF power amplifier according to the first embodiment of the present invention shown in FIG. 1 and FIG. FIG. 5 is a diagram showing a basic configuration of an RF power amplifier according to the second embodiment of the present invention.

1. First, an outline of a typical embodiment of the invention disclosed in the present application will be described. Reference numerals in the drawings referred to with parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

  [1] A typical embodiment of the present invention is an RF power amplifier including an RF amplifier circuit (100) and a second harmonic termination circuit (102).

  When an RF input signal having a plurality of RF frequency bands is supplied to an input terminal of the RF amplifier circuit (100), the RF amplifier circuit (100) performs power amplification of the RF input signal.

  The plurality of RF frequency bands include at least a first frequency band (band 3) having a predetermined frequency band and a second frequency band (band 1) having a frequency band having a frequency higher than the predetermined frequency band. .

  The second harmonic termination circuit (102) includes a capacitor (C5) and an inductor (L3) connected in series between the output terminal of the RF amplifier circuit (100) and a ground potential (GND).

The series resonance frequency (f ₀ ) determined by the capacitance value of the capacitor (C5) of the second harmonic termination circuit (102) and the inductance value of the inductor (L3) is substantially equal to the first frequency band. The lowest frequency (3420 Hz) of the first second harmonic component having twice the frequency and the highest frequency (3960 Hz) of the second second harmonic component having a frequency substantially twice that of the second frequency band. Is set to a set frequency (3495 Hz).

The capacitance (C5) of the second harmonic termination circuit (102) at the lowest frequency, the first series connection impedance (Z _{2HD_L} ) of the inductor (L3), and the second harmonic termination circuit at the highest frequency The capacitance value of the capacitor (C5) is set so that the second series connection impedance (Z _{2HD_H} ) of the capacitor (C5) of (102) and the inductor (L3) is smaller than a predetermined value. (See FIG. 1).

  According to the embodiment, when the termination operation of the plurality of second harmonics of the plurality of transmission RF frequencies of the RF transmission output signal generated by the RF power amplifier is performed by the common second harmonic frequency termination circuit. The termination impedance of the termination operation of the common second harmonic frequency termination circuit can be reduced.

  The RF power amplifier according to the preferred embodiment further comprises an output matching circuit (101).

  An input terminal of the output matching circuit (101) is connected to an output terminal of the RF amplifier circuit (100), and an output terminal of the output matching circuit (101) can be connected to an antenna via a front end module. The output matching circuit (101) performs impedance conversion from the impedance of the output terminal of the RF amplifier circuit (100) to the impedance of the front end module.

  The output matching circuit (101) is a low-pass filter type output matching circuit including at least a filter inductor (L2) and a filter capacitor (C3).

  The low-pass filter type output matching circuit (101) has a function of bypassing the second second harmonic component generated from the output terminal of the RF amplifier circuit (100) to the ground potential (GND). (See FIG. 1).

  In another preferred embodiment, the RF input signal is a transmission signal from an LTE mobile phone terminal to a base station.

  The first frequency band having the predetermined frequency band is an LTE band 3.

  The second frequency band having a frequency band higher than the predetermined frequency band is the LTE band 1.

  The plurality of RF frequency bands of the RF input signal further includes a third frequency band having a frequency band which is LTE band 2.

  The output matching circuit (101) performs termination processing of a third second harmonic component having a frequency substantially twice as high as the third frequency band (see FIG. 1). ).

In still another preferred embodiment, the series resonance frequency (determined by the capacitance value of the capacitance (C5) of the second harmonic termination circuit (102) and the inductance value of the inductor (L3) ( f ₀ ) is set to another set frequency having a substantially intermediate frequency (3495 MHz) in the frequency band (3420 to 3570 Hz) of the first second harmonic component. (See Figure 1).

In a more preferred embodiment, the series resonance frequency (f ₀ ) is larger by a predetermined magnitude (ΔL3) than the inductance value of the inductor (L3) for setting the other set frequency (3495 MHz). An inductance is used for the inductor (L3) of the second harmonic termination circuit (102) (see FIG. 1).

In another more preferred embodiment, an inductance larger by the predetermined magnitude (ΔL3) is used for the inductor (L3) of the second harmonic termination circuit (102), so that the series resonance frequency ( The series resonant impedance (Z ₀ ) of the capacitor (C5) and the inductor (L3) of the second harmonic termination circuit (102) at f ₀ ) is the first operating point (P ₀ ) of the Smith chart. Move to 2 operating points (P ₁ ).

The first operating point and the second operating point are respectively a point (P ₀ ) having a resistance value substantially zero in the Smith chart and a constant resistance circle having a resistance value substantially zero in the Smith chart. And an operating point (P ₁ ) located between the intersection of the constant reactance arcs whose reactance is substantially j4Ω and the resistance value is substantially zero in the Smith chart. Yes (see FIG. 4).

  The RF power amplifier according to still another more preferred embodiment further includes another RF amplifier circuit (100_L), another second harmonic termination circuit (102_L), and another output matching circuit (101_L). .

  When another RF input signal having a plurality of other RF frequency bands is supplied to the input terminal of the other RF amplifier circuit (100_L), the other RF amplifier circuit amplifies the power of the other RF input signal. Execute.

  The plurality of RF frequency bands include an LTE band 5 frequency band and an LTE band 8 frequency band.

  The other second harmonic termination circuit (102_L) includes another capacitor (C5L) connected in series between the output terminal of the other RF amplifier circuit (100_L) and the ground potential (GND) and the other Including an inductor (L3L).

  The input terminal of the other output matching circuit (101_L) is connected to the output terminal of the other RF amplifier circuit (100_L), and the output terminal of the other output matching circuit (101) can be connected to the antenna. The other output matching circuit (101_L) performs impedance conversion from the impedance of the output terminal of the other RF amplifier circuit (100_L) to the impedance of the antenna (see FIG. 5). ).

  In a specific embodiment, the other output matching circuit (101_L) is another low-pass filter type output matching circuit including at least another filter inductor (L2L) and another filter capacitor (C3L). (Refer to FIG. 5).

2. Details of Embodiment Next, the embodiment will be described in more detail. In all the drawings for explaining the best mode for carrying out the invention, components having the same functions as those in the above-mentioned drawings are denoted by the same reference numerals, and repeated description thereof is omitted.

[Embodiment 1]
<< Basic configuration of RF power amplifier >>
FIG. 1 is a diagram showing a basic configuration of an RF power amplifier according to Embodiment 1 of the present invention.

  The RF power amplifier according to the first embodiment of the present invention shown in FIG. 1 includes an RF amplifier circuit 100, a load circuit / output matching circuit 101, and a second harmonic frequency termination circuit 102.

<< RF amplifier circuit >>
An input terminal Input of the RF amplifier circuit 100 is supplied with a high-band transmission frequency input signal having a triple-band transmission RF frequency which is an LTE high band including the LTE band 1, band 2 and band 3, and the RF amplifier circuit. 100 executes power amplification of the high-band transmission frequency input signal.

<< Load circuit / Output matching circuit >>
The load circuit / output matching circuit 101 includes three inductors L1, L2, and L4 and four capacitors C1, C2, C3, and C4. The inductor L1 functions as an RF choke coil as a load of the RF amplifier circuit 100, and the capacitor C1 functions as a decoupling capacitor for attenuating the power supply ripple component included in the power supply voltage Vcc supplied to one end of the inductor L1. .

  The inductor L4 indicates the parasitic inductance of the wiring that connects the output terminal of the RF amplifier circuit 100 and the other end of the inductor L1. The inductor L2, the parasitic inductance L4, and the two capacitors C2 and C3 constitute a low-pass filter (LPF) type output matching circuit. This LPF type output matching circuit performs impedance conversion from a low output impedance of several Ω of the RF amplifier circuit 100 to a front-end module connected to 50 Ω of the antenna of the mobile phone terminal on which the RF power amplifier of FIG. 1 is mounted. Run. The capacitor C4 prevents the DC voltage of the power supply voltage Vcc from being supplied to the antenna of the mobile phone terminal connected to the output terminal Output via the front end module, while the RF amplified output signal of the RF amplifier circuit 100 is supplied to this antenna. Functions as a coupling capacity to supply.

《Second harmonic frequency termination circuit》
The second harmonic frequency termination circuit 102 includes a capacitor C5 and an inductor L3 connected in series between the output terminal of the RF amplifier circuit 100 and the ground potential GND. Due to the low series resonance impedance at the series resonance frequency determined by the capacitor C5 and the inductor L3, the second harmonic component of the RF amplified output signal of the RF amplifier circuit 100 is bypassed to the ground potential GND and transmitted to the output terminal Output. It becomes possible to attenuate the second harmonic output component.

  The second harmonic frequency termination circuit 102 is a common second harmonic that performs the termination operation of all the second harmonics of the triple-band transmission RF frequency of the above-described LTE band 1, band 2, and band 3. Functions as a frequency termination circuit. The transmission RF frequency of LTE system band 1 is 1920 to 1980 MHz, the transmission RF frequency of band 2 of LTE system is 1850 to 1910 MHz, and the transmission RF frequency of band 3 of LTE system is 1710 to 1785 MHz. Accordingly, the second harmonic frequency of the LTE band 1 is 3840 to 3960 MHz, the second harmonic frequency of the LTE band 2 is 3700 to 3820 MHz, and the second harmonic frequency of the LTE band 3 is 3420 to 3920 MHz. 3570 MHz.

  In addition, the second harmonic frequency termination circuit 102 has a unique configuration described below, which is 540 MHz from the lowest frequency of the second harmonic of band 3420 MHz to the highest frequency of the second harmonic of band 1 3960 MHz. When the termination operation of all the second harmonics having a wide frequency band is executed, the termination impedance of the termination operation can be set to a sufficiently low value.

<< Specific configuration of RF power amplifier >>
FIG. 2 is a diagram showing a specific configuration of the RF power amplifier according to the first embodiment of the present invention shown in FIG.

  The RF power amplifier according to the first embodiment of the present invention shown in FIG. 2 includes an RF power module wiring board 200 and a microwave monolithic integrated circuit (MMIC) 201.

<Microwave monolithic integrated circuit chip>
The microwave monolithic integrated circuit chip 201 includes a heterojunction bipolar transistor Q as a final stage amplification element of the RF amplification circuit 100 configured by a multistage amplification circuit and a capacitor C5 of the second harmonic frequency termination circuit 102. For example, the capacitor C5 has a laminated structure of metal, insulator, and metal (MIM: Metal Insulator Metal) integrated on the microwave monolithic integrated circuit chip 201 by a semiconductor manufacturing process.

<< RF power module wiring board >>
The RF power module wiring board 200 includes three inductors L1, L2, and L4 of the load circuit / output matching circuit 101, four capacitors C1, C2, C3, and C4, and an inductor L3 of the second harmonic frequency termination circuit 102. Including. The two inductors L1 and L2 of the load circuit / output matching circuit 101 are constituted by chip inductors which are surface mounted components (SMD: Surface Mount Device), and the four capacitors C1, C2, C3 and C4 are constituted by chip capacitors which are surface mounted components (SMD). The two inductors L3 and L4 are configured by parasitic inductance of bonding wires connected between the pads of the microwave monolithic integrated circuit chip 201 and the pads of the RF power module wiring board 200.

《Details of second harmonic frequency termination circuit》
Next, the second harmonic frequency termination circuit 102 of the RF power amplifier according to the first embodiment of the present invention shown in FIGS. 1 and 2 will be described in detail.

As described above, the second harmonic frequency termination circuit 102 includes the capacitor C5 and the inductor L3 connected in series between the output terminal of the RF amplifier circuit 100 and the ground potential GND. Therefore, the series resonance frequency f ₀ determined by the capacitor C5 and the inductor L3 is expressed by the following equation (1).

Therefore, the series resonance angular frequency ω ₀ corresponding to the series resonance frequency f ₀ is expressed by the following equation (2).

  Therefore, the inductor L3 is expressed by the following equation (3) from the above equation (2).

As a result, the series resonance impedance Z _0, which is determined by the capacitor C5 and the inductor L3 is represented by the following equation (4).

Therefore, from the above equation (4), it is understood that the series resonance impedance Z ₀ of the second harmonic frequency termination circuit 102 becomes zero at the frequency f corresponding to the angular frequency ω equal to the series resonance angular frequency ω _0. The

On the other hand, the frequency and the angular frequency of the lowest frequency 3420 MHz of the second harmonic of the band 3 are set to f _{2HD_L} and ω _{2HD_L} , respectively.

As an example, the series resonance frequency f ₀ determined by the capacitor C5 of the second harmonic frequency termination circuit 102 and the inductor L3 is set to an intermediate frequency of 3495 MHz of 3420 to 3570 MHz as the second harmonic frequency of the LTE band 3. The relationship of f _{2HD_L} <f ₀ is established between the frequency f _{2HD_L} of the lowest frequency 3420 MHz of the second harmonic of the band 3 and the series resonance frequency f ₀ of 3495 MHz of the second harmonic frequency termination circuit 102.

Therefore, the series resonant impedance Z _{2HD_L} determined by the capacitance C5 of the second harmonic frequency termination circuit 102 and the inductor L3 at the frequency f _{2HD_L} of the lowest frequency 3420 MHz of the second harmonic of the band 3 is _{expressed by} the following equation (5). It is.

Therefore, the series resonance impedance Z _{2HD_L} of the second harmonic frequency termination circuit 102 at the frequency f _{2HD_L} of the lowest frequency 3420 MHz of the band 3 second harmonic given by the above equation (5) is, for example, a predetermined value of _0.5Ω . The capacitance value of the capacitor C5 of the second harmonic frequency termination circuit 102 is set to a sufficiently large value so as to be less than the impedance. As a result, by setting the capacitance value of the capacitor C5 to a sufficiently large value, the inductance value of the inductor L3 of the second harmonic frequency termination circuit 102 is set to a sufficiently small value from the above equation (3).

On the other hand, the frequency and the angular frequency of the highest frequency 3960 MHz of the second harmonic of the band 1 are set to f _{2HD_H} and ω _{2HD_H} , respectively. Therefore, the series resonance impedance Z _{2HD_H} determined by the capacitor C 5 of the second harmonic frequency termination circuit 102 and the inductor L 3 at the frequency f _{2HD_H} of the highest frequency 3960 MHz of the second harmonic of the band 1 is _{expressed by} the following equation (6). It is.

Accordingly, the series resonance impedance Z _{2HD_H} of the second harmonic frequency termination circuit 102 at the frequency f _{2HD_H} of the highest frequency 3960 MHz of the second harmonic of the band 1 given by the above equation (6) is, for example, a predetermined value of _0.5Ω . The capacitance value of the capacitor C5 of the second harmonic frequency termination circuit 102 is set to a sufficiently large value so as to be less than the impedance. As a result of setting the capacitance value of the capacitor C5 to a sufficiently large value, the inductance value of the inductor L3 of the second harmonic frequency termination circuit 102 is set to a sufficiently small value from the above equation (3).

《Capacitance dependence of series resonance impedance of second harmonic frequency termination circuit》
FIG. 3 shows the series resonant impedance of the second harmonic frequency termination circuit 102 and the capacitance C5 of the second harmonic frequency termination circuit 102 of the RF power amplifier according to the first embodiment of the present invention shown in FIGS. It is a figure which shows the relationship with a capacitance value.

  The vertical axis in FIG. 3 indicates the value of the series resonance impedance of the second harmonic frequency termination circuit 102, while the horizontal axis in FIG. 3 indicates the frequency of the second harmonic.

As shown in FIG. 3, the value of the series resonance impedance of the second harmonic frequency termination circuit 102 is substantially _zero ohms at the series resonance frequency f ₀ having a frequency of 3495 MHz close to the frequency of 3.5 GHz. The series resonance frequency f ₀ of the frequency 3495 MHz that approximates the frequency 3.5 GHz is determined by the capacitor C5 of the second harmonic frequency termination circuit 102 and the inductor L3, and the second harmonic frequency of the LTE system band 3 is The intermediate frequency of 3420 to 3570 MHz is 3495 MHz.

As shown in FIG. 3, the second harmonic capacitance value of the capacitor C5 of the frequency termination circuit 102 6pF, 8 pF, 10 pF, when the small and 12pF is wider frequency around the series resonance frequency _{f 0} of the frequency 3495MHz In the band, the value of the series resonance impedance of the second harmonic frequency termination circuit 102 does not become a sufficiently low value.

However, as shown in FIG. 3, in the case where the capacitance value of the capacitor C5 of the second harmonic frequency termination circuit 102 is as large as 14 pF, in a wide frequency band centered on the series resonance frequency f ₀ at a frequency of 3495 MHz, The value of the series resonance impedance of the second harmonic frequency termination circuit 102 can be set to a sufficiently low value.

<< Attenuation of second harmonic by LPF type output matching circuit >>
The inductor L2, the parasitic inductance L4, and the two capacitors C2 and C3 of the load circuit / output matching circuit 101 of the RF power amplifier according to the first embodiment of the present invention shown in FIGS. 1 and 2 are a low-pass filter (LPF) type. Output matching circuit.

  This LPF type output matching circuit performs impedance conversion from a low output impedance of several Ω of the RF amplifier circuit 100 to a front-end module connected to 50 Ω of the antenna of the mobile phone terminal on which the RF power amplifier of FIG. 1 is mounted. Thus, the output matching operation is executed, and the second harmonic attenuating operation is executed by the filter characteristic of the low pass filter (LPF). That is, the cutoff frequency of this LPF type output matching circuit is the lower one of the higher frequency 3570 MHz of the third harmonic frequency of the LTE band 3 of 3420 to 3570 MHz and the lower frequency of the second harmonic frequency of the band 2 of 3700 to 3820 MHz. The frequency is set to an intermediate value of 3700 MHz. Therefore, this LPF type output matching circuit grounds the component of the band 2 second harmonic frequency 3700 to 3820 MHz and the component of the band 1 second harmonic frequency 3840 to 3960 MHz included in the output signal of the RF amplifier circuit 100. It also has a function of bypassing to the potential GND. As a result, this LPF type output matching circuit can attenuate the second harmonic output components of band 1 and band 2 transmitted to the output terminal Output.

<< Improvement of ACLR characteristics >>
FIG. 4 is a diagram showing a Smith chart for explaining the characteristics of the second harmonic frequency termination circuit 102 of the RF power amplifier according to the first embodiment of the present invention shown in FIG. 1 and FIG.

  In the Smith chart shown in FIG. 4, the point of normalization (1) at the midpoint of the straight line connecting the point where the resistance value is zero (0) and the point where the resistance value is infinite (∞) is 4Ω. . In the normal Smith chart, the point of normalization (1) at the midpoint of the straight line connecting the point where the resistance value is zero (0) and the point where the resistance value is infinite (∞) is 50Ω. Note that the Smith chart shown in FIG. 4 is different.

The operating point P ₀ of the Smith chart shown in FIG. 4 is the series resonance impedance of the second harmonic frequency termination circuit 102 at the frequency f corresponding to the angular frequency ω equal to the series resonance angular frequency ω ₀ according to the above equation (4). The operating point at which Z ₀ is zero is shown.

According to the study by the present inventors, at the operating point P ₀ of the Smith chart shown in FIG. 4, the power added efficiency (PAE) is good, but the adjacent channel leakage ratio (ACLR) characteristic indicating the distortion characteristic is not good. It has been made clear. An RF power amplifier mounted on a mobile phone terminal that employs a W-CDMA system, a CDMA2000 system, an LTE system, or the like is used to improve a transfer rate of a transmission signal transmitted to a base station. And need to send. Therefore, since this type of RF power amplifier needs to execute a linear amplification operation having high linearity, the adjacent channel leakage ratio (ACLR) characteristic showing the distortion characteristic needs to be good.

  On the other hand, in the second generation (2G) GSM system, if it is not the EDGE system, only the phase modulation signal needs to be transmitted, and there is no need to transmit the amplitude modulation signal. Note that EDGE is an abbreviation for Enhanced Data rate for GSM Evolution. As a result, an RF power amplifier mounted on a mobile phone terminal adopting a normal GSM system performs a saturation amplification operation having nonlinear characteristics in order to transmit only a phase modulation signal. Therefore, an RF power amplifier mounted on a mobile phone terminal that employs a normal GSM system by saturation amplification operation has a good power added efficiency (PAE) characteristic. Further, this type of RF power amplifier is not required to have good adjacent channel leakage ratio (ACLR) characteristics indicating distortion characteristics.

  On the other hand, RF power amplifiers mounted on mobile phone terminals adopting W-CDMA, CDMA2000, or LTE systems should have good power added efficiency (PAE) and adjacent channel leakage ratio (ACLR) characteristics. Is needed.

  As a result of studies by the present inventors, it has been clarified that it is possible to improve both power added efficiency (PAE) and adjacent channel leakage ratio (ACLR) characteristics by making the following design changes. .

That is, starting from the operating point P ₀ of the Smith chart shown in FIG. 4, it is to increase the predetermined value ΔL3 minutes than the design value as described above inductance value of the inductor L3 of the secondary harmonic frequency termination circuit 102. As a result, after a predetermined value increase ΔL3 minutes, the impedance of the secondary harmonic frequency termination circuit 102 is shifted to the operating point P _1. The shift amount from the operating point P ₀ to the operating point P ₁ is jωΔL3. In the example shown in FIG. 4, jωΔL3 is j2Ω. Accordingly, the operating point P ₁ is the intersection of the resistance value and the constant reactance arc 0.5 in the Smith chart shown in FIG. 4 is a constant resistance circle of zero (0).

According to the study by the present inventors, the operating point P ₂ that is the intersection of the constant reactance arc of 1.0 and the resistance circle of zero (0) in the Smith chart shown in FIG. 4 where jωΔL3 is j4Ω. It has been clarified that both the power added efficiency (PAE) and the adjacent channel leakage ratio (ACLR) can be made good between the operating point P ₀ and the operating point P ₀ .

Further, as a result of investigations by the present inventors, the operating point of the movement destination, which is the impedance of the second harmonic frequency termination circuit 102, is the Smith chart shown in FIG. 4 and the resistance value is zero (0) and infinity (∞). It is confirmed that the characteristic of the adjacent channel leakage ratio (ACLR) is deteriorated in comparison with the operating point P ₀ when it exists in a region below the straight line connecting the point.

Note that, by increasing the inductance value of the inductor L3 of the second harmonic frequency termination circuit 102 by a predetermined value ΔL3 from the above-described design value, the resonance frequency f _{0 of the} second harmonic frequency termination circuit 102 according to the above equation (1). Decreases from the original frequency value. However, as described above, the impedance shift amount jωΔL3 due to the increase ΔL3 in the inductance value of the inductor L3 is as small as j4Ω at the maximum.

  On the other hand, in the first embodiment of the present invention, as described above, the band 3 is generated by the action of the capacitor C5 whose capacitance value is set to a sufficiently large value in the second harmonic frequency termination circuit 102 and the LPF type output matching circuit. In a very wide frequency band of 540 MHz from the lowest frequency of the second harmonic of 3420 MHz to the highest frequency of the second harmonic of Band 1 of 3960 MHz, the termination impedance of the termination operation can be made sufficiently low. Therefore, the second harmonic harmonic termination operation in a wide frequency band of the second harmonic frequency termination circuit 102 according to the first embodiment of the present invention is performed by the small impedance shift amount jωΔL3 due to the small increase ΔL3 of the inductance value of the inductor L3. The low impedance characteristic is not impaired.

[Embodiment 2]
<< Basic configuration of RF power amplifier >>
FIG. 5 is a diagram showing a basic configuration of an RF power amplifier according to the second embodiment of the present invention.

  The RF power amplifier according to the second embodiment of the present invention shown in FIG. 5 includes a first RF amplifier circuit 100_H, a first load circuit / output matching circuit 101_H, a first second harmonic frequency termination circuit 102_H, a second RF amplifier circuit 100_L, The circuit includes a second load circuit / output matching circuit 101_L and a second second harmonic frequency termination circuit 102_L.

  The first RF amplifier circuit 100_H, the first load circuit / output matching circuit 101_H, and the first second-harmonic frequency termination circuit 102_H are LTE high band transmission RF frequencies of band 1, band 2, and band 3 LTE. A first path for performing amplification of a high band transmission frequency having (1710 to 1980 MHz) is configured.

  The second RF amplifier circuit 100_L, the second load circuit / output matching circuit 101_L, and the second second-harmonic frequency termination circuit 102_L include the LTE low band transmission RF frequency (824 to 915 MHz) of the band 5 and the band 8 LTE. ) To perform amplification of the low-band transmission frequency. Accordingly, the first path and the second path constitute a dual amplifier architecture as a multiband RF power amplifier.

<< First RF amplifier circuit >>
The input terminal Input_H of the first RF amplifier circuit 100_H is supplied with a high-band transmission frequency input signal having a triple-band transmission RF frequency that is an LTE high-band including the LTE band 1, band 2, and band 3, and the first RF amplification The circuit 100_H performs power amplification of the high band transmission frequency input signal.

<< First load circuit / Output matching circuit >>
The first load circuit / output matching circuit 101_H includes three inductors L1H, L2H, and L4H and four capacitors C1H, C2H, C3H, and C4H. The inductor L1H functions as an RF choke coil as a load of the first RF amplifier circuit 100_H, and the capacitor C1H functions as a decoupling capacitor for attenuating a power supply ripple component included in the power supply voltage Vcc supplied to one end of the inductor L1H. To do.

  The inductor L4H indicates the parasitic inductance of the wiring connecting the output terminal of the first RF amplifier circuit 100_H and the other end of the inductor L1H. The inductor L2H, the parasitic inductance L4H, and the two capacitors C2H and C3H constitute a first low-pass filter (LPF) type output matching circuit. This first LPF type output matching circuit performs impedance conversion from the low output impedance of several Ω of the first RF amplifier circuit 100_H to the front-end module connected to 50Ω of the antenna of the mobile phone terminal. The capacitor C4H prevents the DC voltage of the power supply voltage Vcc from being supplied to the antenna of the mobile phone terminal connected to the output terminal Output_H, and the coupling for supplying the first RF amplified output signal of the first RF amplifier circuit 100_H to the antenna. Acts as a capacity.

<< 1st second harmonic frequency termination circuit >>
The first second harmonic frequency termination circuit 102_H includes a capacitor C5H and an inductor L3H connected in series between the output terminal of the first RF amplifier circuit 100_H and the ground potential GND. Due to the low series resonance impedance at the series resonance frequency determined by the capacitor C5H and the inductor L3H, the second harmonic component of the first RF amplification output signal of the first RF amplifier circuit 100_H is bypassed to the ground potential GND, and is connected to the first output terminal Output_H. The transmitted second harmonic output component can be attenuated.

  The first second-harmonic frequency termination circuit 102_H performs a common first-second termination operation for all the second-harmonic transmission frequencies of the above-described LTE band 1, band 2, and band 3 triple-band transmission RF frequencies. Functions as a second harmonic frequency termination circuit. The transmission RF frequency of LTE system band 1 is 1920 to 1980 MHz, the transmission RF frequency of band 2 of LTE system is 1850 to 1910 MHz, and the transmission RF frequency of band 3 of LTE system is 1710 to 1785 MHz. Accordingly, the second harmonic frequency of the LTE band 1 is 3840 to 3960 MHz, the second harmonic frequency of the LTE band 2 is 3700 to 3820 MHz, and the second harmonic frequency of the LTE band 3 is 3420 to 3920 MHz. 3570 MHz.

  Further, the first second harmonic frequency termination circuit 102_H has the same configuration as the second harmonic frequency termination circuit 102 according to the first embodiment of the present invention described above. Therefore, by using the first second harmonic frequency termination circuit 102_H, an extremely wide frequency band of 540 MHz from the lowest frequency 3420 MHz of the second harmonic of the band 3 to the highest frequency 3960 MHz of the second harmonic of the band 1 is obtained. When the termination operation of all the second harmonics having the above is executed, the termination impedance of the termination operation can be set to a sufficiently low value.

<< Second RF amplifier circuit >>
A low-band transmission frequency input signal having a dual-band transmission RF frequency which is an LTE low band including the LTE band 5 and the band 8 is supplied to the input terminal Input_L of the second RF amplifier circuit 100_L. The second RF amplifier circuit 100_L Performs power amplification of the transmission frequency input signal.

<< Second load circuit / Output matching circuit >>
The second load circuit / output matching circuit 101_L includes three inductors L1L, L2L, and L4L and four capacitors C1L, C2L, C3L, and C4L. The inductor L1L functions as an RF choke coil as a load of the second RF amplifier circuit 100_L, and the capacitor C1L functions as a decoupling capacitor for attenuating a power supply ripple component included in the power supply voltage Vcc supplied to one end of the inductor L1L. To do.

  The inductor L4L indicates the parasitic inductance of the wiring connecting the output terminal of the second RF amplifier circuit 100_L and the other end of the inductor L1L. The inductor L2L, the parasitic inductance L4L, and the two capacitors C2L and C3L constitute a second low-pass filter (LPF) type output matching circuit. The second LPF type output matching circuit performs impedance conversion from a low output impedance of several Ω of the second RF amplifier circuit 100_L to a front-end module connected to 50Ω of the antenna of the mobile phone terminal. The capacitor C4L prevents the DC voltage of the power supply voltage Vcc from being supplied to the antenna of the mobile phone terminal connected to the output terminal Output_H, and the coupling for supplying the second RF amplified output signal of the second RF amplifier circuit 100_L to the antenna. Acts as a capacity.

<< 2nd second harmonic frequency termination circuit >>
The second second harmonic frequency termination circuit 102_L includes a capacitor C5L and an inductor L3L connected in series between the output terminal of the second RF amplifier circuit 100_L and the ground potential GND. Due to the low series resonance impedance at the series resonance frequency determined by the capacitor C5L and the inductor L3L, the second harmonic component of the second RF amplification output signal of the second RF amplifier circuit 100_L is bypassed to the ground potential GND, and is connected to the second output terminal Output_L. The transmitted second harmonic output component can be attenuated.

  The second second harmonic frequency termination circuit 102_L is a common second second harmonic that performs the termination operation of all the second harmonics of the dual-band transmission RF frequencies of the LTE band 5 and band 8 described above. Functions as a frequency termination circuit. The transmission frequency of the LTE band 5 is 824 to 849 MH, and the transmission frequency of the LTE band 8 is 880 to 915 MHz. Therefore, the second harmonic frequency of LTE band 5 is 1648 to 1698 MHz, and the second harmonic frequency of band 8 of LTE is 1760 to 1830 MHz.

  Furthermore, the second second harmonic frequency termination circuit 102_L has substantially the same configuration as the second harmonic frequency termination circuit 102 of the first embodiment of the present invention described above. As a result, by using the second second harmonic frequency termination circuit 102_L, a relatively wide 176 MHz from the lowest frequency 1648 MHz of the second harmonic of the band 5 to the highest frequency 1824 MHz of the second harmonic of the band 8 is relatively wide. When the termination operation of all second harmonics having a frequency band is executed, the termination impedance of the termination operation can be set to a sufficiently low value.

  Although the invention made by the present inventor has been specifically described based on various embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the scope of the invention. Yes.

  For example, in the present invention, the final stage amplification element of the RF amplification circuit constituted by the multistage amplification circuit is not limited to the heterojunction bipolar transistor, but other LD (Laterally Diffused) type power MOS transistors, MESFETs, and the like. It is also possible to use transistors.

  The RF power amplifier according to the present invention further includes a first path for amplifying a high-band transmission frequency having a high-band transmission RF frequency of the LTE system and a low-band transmission frequency having a low-band transmission RF frequency of the LTE system. It is possible to include not only the second path to be performed but also other stages of multi-stage amplifier circuits for performing transmission frequency amplification of other systems. For example, the third path that performs amplification of the GSM low band transmission frequency of the GSM850 system and the GSM900 system and the fourth path that performs amplification of the GSM high band transmission frequency of the DCS1800 system and the PCS1900 system are described in the present invention. It is also possible for the RF power amplifier of the present invention to include. At that time, the second harmonic frequency termination circuit of each path of the third path and the fourth path is realized by substantially the same configuration as the second harmonic frequency termination circuit 102 of the first embodiment of the present invention described above. It is possible.

DESCRIPTION OF SYMBOLS 100 ... RF power amplifier circuit 101 ... Load circuit and output matching circuit 102 ... Second harmonic termination circuit L1-L4 ... Inductor C1-C5 ... Capacitance Vcc ... Power supply voltage GND ... Ground potential Input ... Input terminal Output ... Output terminal 200 ... RF power module wiring board 201 ... Microwave monolithic integrated circuit chip (MMIC)
DESCRIPTION OF SYMBOLS 100_H ... High band RF power amplifier circuit 101_H ... High band load circuit and output matching circuit 102_H ... High band 2nd harmonic termination circuit L1H-L4H ... High band inductor C1H-C5H ... High band capacity Input_H ... High band input terminal Output_H: High band output terminal 100_L ... Low band RF power amplifier circuit 101_L ... Low band load circuit / output matching circuit 102_L ... Low band second harmonic termination circuit L1H-L4L ... Low band inductor C1H-C5L ... Low band capacitance Input_L ... Low band input terminal Output_L: Low-band output terminal

Claims (8)

An RF power amplifier comprising an RF amplifier circuit and a second harmonic termination circuit,
By supplying an RF input signal having a plurality of RF frequency bands to the input terminal of the RF amplifier circuit, the RF amplifier circuit performs power amplification of the RF input signal,
The plurality of RF frequency bands include at least a first frequency band having a predetermined frequency band and a second frequency band having a frequency band having a frequency higher than the predetermined frequency band,
The second harmonic termination circuit includes a capacitor and an inductor connected in series between the output terminal of the RF amplifier circuit and a ground potential,
The series resonant frequency determined by the capacitance value of the capacitor of the second harmonic termination circuit and the inductance value of the inductor is a first second harmonic having a frequency substantially twice that of the first frequency band. Set to a set frequency between the lowest frequency of the component and the highest frequency of the second second harmonic component having a frequency substantially twice that of the second frequency band;
The capacitance of the second harmonic termination circuit at the lowest frequency and the first series connection impedance of the inductor, the capacitance of the second harmonic termination circuit at the highest frequency and the second series connection impedance of the inductor. An RF power amplifier, wherein the capacitance value of the capacitor is set to be smaller than a predetermined value. In claim 1,
The RF power amplifier further comprises an output matching circuit,
An input terminal of the output matching circuit is connected to an output terminal of the RF amplifier circuit, an output terminal of the output matching circuit is connectable to an antenna through a front end module, and the output matching circuit is connected to the RF amplifier circuit. Performing impedance conversion from the impedance of the output terminal to the impedance of the front end module;
The output matching circuit is a low-pass filter type output matching circuit including at least a filter inductor and a filter capacitor,
The low-pass filter type output matching circuit has a function of bypassing the second second harmonic component generated from the output terminal of the RF amplifier circuit to the ground potential. In claim 2,
The RF input signal is a transmission signal from an LTE mobile phone terminal to a base station,
The first frequency band having the predetermined frequency band is an LTE band 3;
The second frequency band having a frequency band higher than the predetermined frequency band is LTE band 1;
The plurality of RF frequency bands of the RF input signal further includes a third frequency band having a frequency band that is a band 2 of the LTE scheme,
The RF power amplifier, wherein the output matching circuit performs termination processing of a third second-order harmonic component having a frequency that is substantially twice the third frequency band. In claim 3,
The series resonance frequency determined by the capacitance value of the capacitance of the second harmonic termination circuit and the inductance value of the inductor is a substantially intermediate frequency in the frequency band of the first second harmonic component. An RF power amplifier set to another set frequency having In claim 4,
An inductance larger than the inductance value of the inductor for setting the series resonance frequency to the other set frequency by a predetermined magnitude is used for the inductor of the second harmonic termination circuit. RF power amplifier. In claim 5,
By using an inductance larger than the predetermined amount for the inductor of the second harmonic termination circuit, the capacitance of the second harmonic termination circuit and the series resonance impedance of the inductor at the series resonance frequency are , Move from the first operating point of the Smith chart to the second operating point,
The first operating point and the second operating point are respectively a point where the resistance value is substantially zero in the Smith chart, a constant resistance circle where the resistance value is substantially zero in the Smith chart, and the Smith chart. And an operating point located between an intersection of constant reactance arcs having a reactance of substantially j4Ω and the point having a resistance value of substantially zero. In claim 3,
The RF power amplifier further includes another RF amplifier circuit, another second harmonic termination circuit, and another output matching circuit,
When another RF input signal having a plurality of other RF frequency bands is supplied to the input terminal of the other RF amplifier circuit, the other RF amplifier circuit performs power amplification of the other RF input signal. And
The plurality of RF frequency bands include an LTE band 5 frequency band and an LTE band 8 frequency band,
The other second harmonic termination circuit includes another capacitor and another inductor connected in series between the output terminal of the other RF amplifier circuit and the ground potential,
An input terminal of the other output matching circuit is connected to the output terminal of the other RF amplifier circuit, an output terminal of the other output matching circuit is connectable to the antenna, and the other output matching circuit is An RF power amplifier that performs impedance conversion from the impedance of the output terminal of another RF amplifier circuit to the impedance of the antenna. In claim 7,
The RF power amplifier, wherein the other output matching circuit is another low-pass filter type output matching circuit including at least another filter inductor and another filter capacitor.

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