CN106257827A - Symmetrical Doherty Doherty power amplifier device and power amplifier - Google Patents

Abstract

The present invention provides a symmetrical Doherty power amplifier circuit device and a power amplifier, wherein the symmetrical Doherty power amplifier includes: a main power amplification channel and one or more auxiliary power amplification channels, and the DOHERTY power amplifier also includes: a reactance The power-variable network is set on the auxiliary power amplification channel; the additional phase-shifting network is set on the main power amplification channel, wherein the first phase is the input signal received by the input end of the main power amplification channel and the auxiliary power amplification channel. The input terminal receives the phase difference between the input signals, and the second phase is the phase difference between the output signal output from the output terminal of the main power amplifying channel and the output signal output from the output terminal of the auxiliary power amplifying channel. The problem that the symmetrical DOHERTY power amplifier circuit in the related art cannot meet the higher peak-to-average ratio requirement is solved.

Description

Symmetrical Doherty Power Amplifier Circuit Device and Power Amplifier

technical field

The invention relates to the communication field, in particular to a symmetrical Doherty power amplifier circuit device and a power amplifier.

Background technique

At present, with the increasingly fierce competition in the wireless communication market, the performance of base station products has become the main focus of competition in the industry. As an important part of the base station, the power amplifier (referred to as the power amplifier) is directly related to the quality of the base station's transmitted signal and the communication effect. In order to increase the transmission rate and utilize spectrum resources more effectively, base stations currently widely adopt Orthogonal Frequency Division Multiplexing (OFDM for short) and Quadrature Phase Shift Keying (Quadrature Phase Shift Keyin for short). QPSK) and other peak-to-average ratio modulation methods, so the power amplifier is required to work normally under the peak-to-average ratio condition, not only to meet the linear index requirements, but also to achieve high work efficiency. At this stage, DOHERTY power amplifiers cooperate with digital pre-distortion technology (Digital Pre -distortion, referred to as DPD) can better meet the above requirements, therefore, Doherty power amplifier has become a research hotspot in base station applications.

FIG. 1 is a schematic circuit diagram of a Doherty power amplifier in the related art. As shown in FIG. 1 , it consists of two or more power amplifier tubes, which are divided into a main power amplifier PA1 and an auxiliary power amplifier PA2. The input signal is sent to the main power amplifier PA1 and the auxiliary power amplifier PA2 through the bridge separation, and then synthesized into one after being amplified by two channels respectively. In order to compensate for the 90° phase difference brought by the bridge, the output of the main power amplifier PA1 needs to be phase aligned through a 1/4 wavelength microstrip line. Symmetrical DOHERTY power amplifier, since the main power amplifier PA1 and the auxiliary power amplifier PA2 both use the same power tube and basically the same structure, it has the characteristics of relatively easy design and good production consistency. has been widely applied. In this case, when the output power of the main power amplifier PA1 is small, the auxiliary power amplifier PA2 is in the off state. In order to reduce the influence of the auxiliary power amplifier PA2 on the main power amplifier PA1 at this time, it is necessary to use an OFFSET impedance line with an appropriate electrical length to reduce the power of the auxiliary power amplifier PA2. The turn-off impedance of the tube is transformed to make it present a high-impedance open circuit state to the main power amplifier PA1 at the junction point of the power synthesis unit, and when the output power of the main power amplifier PA1 gradually increases, the auxiliary power amplifier PA2 starts to work, and at the same time PA1 carries out load modulation so that the output impedance of the main power amplifier PA1 power tube continuously shifts from the highest efficiency point to the maximum power point, and finally reaches the maximum power point output impedance together with the auxiliary power amplifier PA2 power tube. In this case, the symmetrical Doherty power tube saturation power The impedance of the maximum efficiency point and the impedance of the maximum efficiency point need to meet the impedance relationship of the standing wave ratio of 2:1, and the impedance relationship of the power tube of the main power amplifier is required to be greater than 2:1 in the peak-to-average ratio application. However, due to the symmetrical Doherty main power amplifier PA1 at this time The output impedance of the power tube cannot meet the requirement of greater than the standing wave 2:1 impedance when the auxiliary power amplifier is working for load modulation, which will affect the efficiency or output power of the symmetrical DOHERTY power amplifier.

At the same time, in practical applications, the impedance relationship between the maximum saturated power point and the maximum efficiency point of some power tubes is greater than 2:1 VSWR. Select the appropriate impedance in the area near the point to make a performance compromise, so that the two can meet the 2:1 standing wave ratio relationship, which will also lose some output power and work efficiency.

Aiming at the problem in the related art that the symmetrical DOHERTY power amplifier circuit cannot meet the higher peak-to-average ratio requirement, no effective solution has been proposed yet.

Contents of the invention

The present invention provides a symmetrical Doherty power amplifier circuit device and a power amplifier to at least solve the problem in the related art that the symmetrical DOHERTY power amplifier circuit cannot meet the higher peak-to-average ratio requirement.

According to one aspect of the present invention, a symmetrical Doherty power amplifier circuit device is provided, including: a power distribution unit, which is used to distribute the input signal into multiple signals with a predetermined phase difference, and output them to the main amplification channel and the auxiliary signal respectively. Amplifying channel; main amplifying channel, comprising: an additional phase-shifting network, a main amplifying channel microstrip line connected to the additional phase-shifting network, a main amplifier connected to the main amplifying channel microstrip line, for passing through the additional The phase-shifting network and the microstrip line of the main amplification channel perform phase alignment of the signal of the main amplification channel and the signal of the auxiliary amplification channel, and the power amplification of the signal of the main amplification channel is performed through the main amplifier; at least one auxiliary amplification channel includes: auxiliary amplification channel The microstrip line, the auxiliary amplifier connected to the auxiliary amplifier channel microstrip line, and the reactance variable network connected to the auxiliary amplifier channel are used to communicate the auxiliary amplifier channel signal with the main channel signal through the auxiliary amplifier channel microstrip line. The phase alignment of the amplified channel signal is carried out through the auxiliary amplifier to amplify the power of the auxiliary amplified channel signal. In the high-efficiency working state of the small signal of the main amplifier, the reactance is reduced by the network that changes with the output power when the auxiliary amplifier is cut off. The turn-off impedance of the waypoint reaches a predetermined value; the power combination unit is used to combine the signals input by the main amplification channel and the auxiliary amplification channel into one signal at the combination point and then output it.

Optionally, the phase characteristic of the additional phase shifting network is the same as that of the reactance varying with output power network.

Optionally, the additional phase-shifting network is used for: offsetting the phase difference caused by the reactance varying with the output power network.

Optionally, the microstrip line of the main amplification channel is used to cancel the predetermined phase difference and the phase difference caused by the microstrip line of the auxiliary amplification channel and the auxiliary amplifier.

Optionally, the microstrip line of the auxiliary amplification channel is used to cancel the phase difference caused by the microstrip line of the main amplification channel and the main amplifier.

Optionally, the reactance varying with output power network is used to: reduce the turn-off impedance to a predetermined value.

Optionally, the additional phase-shifting network is: a biased microstrip line, an inductor-capacitor LC phase-shifting network, or a resistor-capacitor RC phase-shifting network.

Optionally, the reactance varying with output power network is: a bias microstrip line, a varactor diode, or a variable reactance circuit.

Optionally, the main amplification channel microstrip line includes: a first biased microstrip line connected to the additional phase-shifting network, a second biased microstrip line connected to the output end of the main amplifier, and a A 1/4 wavelength microstrip line connected to the second biased microstrip line.

Optionally, the microstrip line of the auxiliary amplification channel includes: a third biased microstrip line connected to the power distribution unit, and a fourth biased microstrip line connected to the reactance varying with output power network.

According to another aspect of the present invention, there is also provided a symmetrical Doherty power amplifier, including: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel includes: sequentially connected in series The first compensation microstrip line, the main power amplifier and the second compensation microstrip line; each of the auxiliary power amplification channels includes: the third compensation microstrip line, the auxiliary power amplifier and the fourth compensation microstrip line connected in series in sequence , wherein the DOHERTY power amplifier further includes: a reactance varying with power network, disposed on the auxiliary power amplification channel, wherein the reactance varying with power network is used to set the turn-off impedance of the auxiliary power amplifier to The first predetermined threshold; an additional phase-shifting network, set on the main power amplification channel, wherein the additional phase-shifting network is used to make the first phase difference the same as the second phase difference, wherein the first phase is The phase difference between the input signal received by the input end of the main power amplifying channel and the input signal received by the input end of the auxiliary power amplifying channel, the second phase is output by the output end of the main power amplifying channel The phase difference between the output signal of and the output signal output from the output terminal of the auxiliary power amplification channel.

Optionally, the reactance varying with power network is connected between the auxiliary power amplifier and the fourth compensation microstrip line, or, the reactance varying with power network is connected between the fourth compensation microstrip line and between the output ends of the auxiliary power amplification channels.

Optionally, the additional phase-shifting network is connected between the input end of the main power amplification channel and the first compensation microstrip line, or, the additional phase-shifting network is connected between the first compensation microstrip line line and the main power amplifier.

Optionally, the phase and frequency characteristics of the additional phase shifting network are the same as the phase and frequency characteristics of the reactance varying with power network.

Optionally, the reactance varies with power network, the additional phase shifting network, the first compensation microstrip line, the second compensation microstrip line, the third compensation microstrip line and the fourth Compensating microstrip lines are commonly used to make the first phase difference the same as the second phase difference.

Optionally, the fourth compensation microstrip line is used to make the impedance of the auxiliary power amplification channel be a second predetermined threshold and adjust the shutdown impedance of the auxiliary power amplifier to a third predetermined threshold, wherein the The third predetermined threshold is greater than the first predetermined threshold.

Optionally, the DOHERTY power amplifier further includes: a power distribution unit for distributing power, wherein the input end of the power distribution unit is used to receive an input signal, and the first output end of the power distribution unit is connected to the The input terminal of the additional phase-shifting network, the second output terminal of the power distribution unit is connected to the third compensation microstrip line; the power combination unit for combining power, wherein the first input of the power combination unit terminal is connected to the second compensation microstrip line through a microstrip impedance transformation line, the second input terminal of the power combining unit is connected to the fourth compensation microstrip line, or the second input terminal of the power combining unit Connect with the reactance varying with power network.

Optionally, the power distribution unit distributes the input signal into multiple signals with a phase difference of 90°, and inputs the multiple signals to the main power amplification channel and the one or more auxiliary channels respectively. Power amplification channel.

Optionally, the power of each signal of the multiple signals is 1/N of the power of the input signal, where N is the number of the multiple signals.

Optionally, the power distribution unit includes a bridge.

Optionally, the additional phase-shifting network includes at least one of the following: a microstrip line; an LC phase-shifting network composed of an inductor and a capacitor; an RC phase-shifting network composed of a capacitor and a resistor.

Optionally, the reactance varying with power network includes at least one of the following: a microstrip line; a varactor diode; and a reactance circuit.

Through the present invention, a symmetrical Doherty DOHERTY power amplifier is adopted, including: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel includes: first compensation microstrip lines connected in series in sequence, The main power amplifier and the second compensation microstrip line; each auxiliary power amplification channel includes: the third compensation microstrip line, the auxiliary power amplifier and the fourth compensation microstrip line connected in series in sequence, wherein the DOHERTY power amplifier also includes: reactance The power-variable network is set on the auxiliary power amplification channel, wherein the reactance power-variable network is used to set the turn-off impedance of the auxiliary power amplifier to a first predetermined threshold; the additional phase-shifting network is set on the main power amplification channel, Wherein, the additional phase-shifting network is used to make the first phase difference the same as the second phase difference, wherein the first phase receives the input signal received by the input end of the main power amplification channel and the input signal received by the input end of the auxiliary power amplification channel The second phase is the phase difference between the output signal output from the output terminal of the main power amplifying channel and the output signal output from the output terminal of the auxiliary power amplifying channel. It solves the problem that the symmetrical DOHERTY power amplifier circuit in the related art cannot adapt to the higher peak-to-average ratio requirements, and then achieves the relationship between the saturation power of the main power amplifier and the impedance of the maximum efficiency point, and expands the application of the symmetrical DOHERTY power amplifier circuit. range, it can improve the efficiency of the symmetrical DOHERTY power amplifier circuit in the peak-to-average ratio application, so that the symmetrical DOHERTY power amplifier circuit can adapt to the higher peak-to-average ratio requirements, and at the same time it can improve the linearity of the power amplifier to a certain extent.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

FIG. 1 is a schematic circuit diagram of a Doherty power amplifier in the related art;

Fig. 2 is a schematic structural diagram of a DOHERTY power amplifier according to an embodiment of the present invention;

3 is a schematic diagram (1) of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention;

4 is a schematic diagram (2) of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention;

5 is a schematic diagram of the off-impedance when the auxiliary amplifier is off in the related art;

6 is a schematic diagram of an auxiliary amplifier turn-off impedance according to an embodiment of the present invention;

7 is a schematic diagram of the impedance of the junction point when the auxiliary amplifier transitions from the cut-off working state to the high power output state according to an embodiment of the present invention;

Fig. 8 is a characteristic curve diagram of the output power and the additional phase shift introduced by the reactance with the power variation network according to an embodiment of the present invention;

Fig. 9 is a characteristic curve diagram of DOHERTY power amplifier output power and additional phase shift in the related art;

Fig. 10 is a characteristic curve diagram of output power and additional phase shift of a DOHERTY power amplifier according to an embodiment of the present invention.

detailed description

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence.

In this embodiment, a symmetrical Doherty DOHERTY power amplifier is provided. FIG. 2 is a schematic structural diagram of a DOHERTY power amplifier according to an embodiment of the present invention. As shown in FIG. 2 , it includes: a main power amplification channel 22 and one or more Auxiliary power amplifying channels 24, wherein the main power amplifying channel 22 includes: first compensation microstrip lines, main power amplifiers and second compensation microstrip lines connected in series; each auxiliary power amplifying channel 24 includes: sequentially connected in series The third compensation microstrip line, the auxiliary power amplifier and the fourth compensation microstrip line, wherein the DOHERTY power amplifier also includes: a reactance varying with power network 242, which is arranged on the auxiliary power amplification channel 24, wherein the reactance varies with power network 242 is used to set the turn-off impedance of the auxiliary power amplifier to the first predetermined threshold; the additional phase shifting network 222 is arranged on the main power amplification channel 22, wherein the additional phase shifting network 222 is used to make the first phase difference and the second The phase difference is the same, wherein, the first phase is the phase difference between the input signal received by the input end of the main power amplification channel and the input signal received by the input end of the auxiliary power amplification channel, and the second phase is the phase difference between the input signal received by the input end of the main power amplification channel. The phase difference between the output signal output from the output terminal of the power amplifying channel and the output signal output from the output terminal of the auxiliary power amplifying channel.

Through the additional phase-shifting network added to the main power amplification channel in the above-mentioned DOHERTY power amplifier and the reactance change network added to the auxiliary power amplification channel, through the adjustment of the additional phase-shifting network and the auxiliary power amplification channel, the symmetrical DOHERTY in the related art is solved. The power amplifier circuit cannot adapt to the higher peak-to-average ratio requirements, thereby improving the relationship between the saturation power of the main power amplifier and the impedance of the maximum efficiency point, expanding the application range of the symmetrical DOHERTY power amplifier circuit, and improving the peak performance of the symmetrical DOHERTY power amplifier circuit. The efficiency of the average ratio application enables the symmetrical DOHERTY power amplifier circuit to adapt to the higher peak-to-average ratio requirements, and at the same time it has the effect of improving the linearity of the power amplifier.

The reactance varying with power network 242 is arranged on the auxiliary power amplification channel 24. In an optional embodiment, the reactance varying with power network 242 is connected between the auxiliary power amplifier and the fourth compensation microstrip line, or the reactance varies with power The network 242 is connected between the fourth compensation microstrip line and the output terminal of the auxiliary power amplification channel.

The additional phase shifting network 222 is arranged on the main power amplification channel 22. In an optional embodiment, the additional phase shifting network 222 is connected between the input end of the main power amplification channel 22 and the first compensation microstrip line, or the additional phase shifting network 222 The phase network 222 is connected between the first compensation microstrip line and the main power amplifier.

In an alternative embodiment, the phase and frequency characteristics of the additional phase shifting network 222 are the same as the phase and frequency characteristics of the reactance versus power network 242 .

In an optional embodiment, the reactance varying with power network 242, the additional phase shifting network 222, the first compensation microstrip line, the second compensation microstrip line, the third compensation microstrip line and the fourth compensation microstrip line are commonly used In order to make the first phase difference the same as the second phase difference.

In an optional embodiment, the fourth compensation microstrip line is used to make the impedance of the auxiliary power amplification channel be the second predetermined threshold and adjust the turn-off impedance of the auxiliary power amplifier to the third predetermined threshold, wherein the third The predetermined threshold is greater than the first predetermined threshold.

The DOHERTY power amplifier also includes other parts in order to better make the symmetrical DOHERTY power amplifier circuit adapt to higher peak-to-average ratio requirements. In an optional embodiment, the DOHERTY power amplifier further includes a power distribution unit for distributing power, wherein the input terminal of the power distribution unit is used to receive the input signal, and the first output terminal of the power distribution unit is connected to the additional phase-shifting unit. The input end of the network, the second output end of the power distribution unit is connected to the third compensation microstrip line; the power combination unit for synthesizing power, wherein, the first input end of the power combination unit is connected to the third compensation microstrip line through the microstrip impedance transformation line The second compensation microstrip line is connected, and the second input end of the power combining unit is connected with the fourth compensation microstrip line, or the second input end of the power combining unit is connected with the reactance varying with power network.

In an optional embodiment, the power distribution unit distributes the input signal into multiple signals with a phase difference of 90°, and inputs the multiple signals to the main power amplification channel and the one or more auxiliary power channels respectively. Zoom in on the channel.

In an optional embodiment, the power of each signal of the multiple signals is 1/N of the power of the input signal, where N is the number of the multiple signals.

In an alternative embodiment, the power distribution unit comprises an electrical bridge.

The aforementioned additional phase-shifting network 222 can be composed in various ways, which will be illustrated below with examples. In an optional embodiment, the additional phase-shifting network 222 includes at least one of the following: a microstrip line; an LC phase-shifting network composed of an inductor and a capacitor; and an RC phase-shifting network composed of a capacitor and a resistor.

The above-mentioned reactance varying with power network 224 may also have various composition modes, which will be described with examples below. In an optional embodiment, the reactance varying with power network 224 includes at least one of the following: a microstrip line; a varactor diode; and a reactance circuit.

In this embodiment, a symmetrical Doherty power amplifier circuit device is also provided, which is used to implement the above embodiments and preferred implementation modes, and those that have already been described will not be repeated. As used below, the term "module" may be a combination of software and/or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated.

In this embodiment, a symmetrical Doherty power amplifier circuit device is also provided, including: a power distribution unit, which is used to distribute the input signal into multiple signals with a predetermined phase difference, and output them to the main amplification channel and the auxiliary amplification channel respectively channel; the main amplification channel, including: an additional phase-shifting network, a main amplification channel microstrip line connected to the additional phase-shifting network, and a main amplifier connected to the main amplification channel microstrip line for passing through the additional phase-shifting network, and the main amplifier channel microstrip line for phase alignment of the main amplifier channel signal and the auxiliary amplifier channel signal, through which the main amplifier performs power amplification on the main amplifier channel signal; at least one auxiliary amplifier channel includes: the auxiliary amplifier channel microstrip line, and The auxiliary amplifier connected to the microstrip line of the auxiliary amplification channel, and the reactance change network connected to the auxiliary amplifier with the output power are used for phase alignment of the signal of the auxiliary amplification channel and the signal of the main amplification channel through the microstrip line of the auxiliary amplification channel. The auxiliary amplifier amplifies the power of the auxiliary amplifier channel signal, and in the high-efficiency working state of the main amplifier small signal, through the reactance and output power variation network, the shutdown impedance of the auxiliary amplifier at the junction point is reduced to a predetermined value when the auxiliary amplifier is cut off; the power The combining unit is used to combine the signals input by the main amplification channel and the auxiliary amplification channel into one signal at the combining point and then output it.

Through the additional phase-shifting network added to the main power amplification channel in the above-mentioned DOHERTY power amplifier circuit device and the reactance varying with power network added to the auxiliary power amplification channel, through the adjustment of the additional phase-shifting network and the auxiliary power amplification channel, the symmetry in the related art is solved. The DOHERTY power amplifier circuit cannot adapt to the higher peak-to-average ratio requirements, thereby improving the relationship between the saturation power of the main power amplifier and the impedance of the maximum efficiency point, expanding the application range of the symmetrical DOHERTY power amplifier circuit, and improving the performance of the symmetrical DOHERTY power amplifier circuit. The efficiency of the peak-to-average ratio application enables the symmetrical DOHERTY power amplifier circuit to adapt to the higher peak-to-average ratio requirements, and at the same time, it can also improve the linearity of the power amplifier to a certain extent.

In an optional embodiment, the phase characteristic of the additional phase shifting network is the same as that of the reactance varying with output power network.

In an optional embodiment, the additional phase shifting network is used to cancel the phase difference caused by the reactance varying with output power network.

In an optional embodiment, the microstrip line of the main amplifying channel is used to cancel the predetermined phase difference and the phase difference caused by the microstrip line of the auxiliary amplifying channel and the auxiliary amplifier.

In an optional embodiment, the microstrip line of the auxiliary amplification channel is used to cancel the phase difference caused by the microstrip line of the main amplification channel and the main amplifier.

In an optional embodiment, the reactance varying with output power network is used to reduce the value of the inductive impedance or capacitive impedance at the junction point by controlling the value of the inductive impedance or capacitive impedance caused by the main amplifier in the small-signal high-efficiency working state Off impedance to a predetermined value.

In an optional embodiment, the additional phase-shifting network is: a biased microstrip line, an inductor-capacitor LC phase-shifting network, or a resistor-capacitor RC phase-shifting network.

In an optional embodiment, the reactance varying with output power network is: a bias microstrip line, a varactor diode, or a variable reactance circuit.

In an optional embodiment, the main amplification channel microstrip line includes: a first biased microstrip line connected to the additional phase-shifting network, a second biased microstrip line connected to the output end of the main amplifier, and a The second biased microstrip line is connected to a 1/4 wavelength microstrip line.

In an optional embodiment, the microstrip line of the auxiliary amplification channel includes: a third biased microstrip line connected to the power distribution unit, and a fourth biased microstrip line connected to the reactance varying with output power network.

The main purpose of the optional embodiment of the present invention is to provide a symmetrical DOHERTY power amplifier circuit, aiming at improving the efficiency of the symmetrical DOHERTY power amplifier circuit in peak-to-average ratio applications, and at the same time having the effect of improving the linearity of the power amplifier.

An optional embodiment of the present invention proposes a DOHERTY power amplifier circuit. Figure 3 is a schematic diagram of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention. 4 and at least one auxiliary amplifying unit 3 and an additional phase-shifting network 8 connected in series to the main amplifying unit 2 and a reactance varying with output power network 9 connected in series at the output end of the auxiliary amplifier, and related OFFSET connecting lines 6, 7, 10, 11 and 1/4 wavelength impedance transformation lines 5. The additional phase shifting network 8 has the same phase characteristics as the reactance varying with output power network 9 and is used to offset the phase difference introduced by increasing the reactance varying with output power network 9 .

The power distribution unit 1 includes an electric bridge, the input end of the electric bridge is connected with the input signal, and the two output ends are respectively connected with the additional phase-shifting network 8 of the main amplifying unit and the input OFFSET line 6 of the auxiliary amplifying unit.

Main amplifying unit 2 comprises main amplifier, and auxiliary amplifying unit 3 comprises auxiliary amplifier, and additional phase-shifting network 8 is connected to the output end of electric bridge, and the input end of main amplifier is connected with additional phase-shifting network 8 by OFFSET line 7, and main amplifier PA3 A 1/4 wavelength microstrip impedance transformation line 5 is connected between the output end and the power combining unit 4 .

Fig. 4 further refines the block diagram of Fig. 3 combined with specific examples. The power distribution unit distributes the input signal into several signals with a phase difference of 90°, and then outputs them to the main amplifier unit and the auxiliary amplifier unit for amplification;

The main amplification channel is composed of an additional phase-shifting network 8, an input OFFSET line 7, a main amplifier PA3, an output OFFSET line 10, and a 1/4 wavelength microstrip impedance conversion line 5, and an input offset line 6, an auxiliary amplifier PA4, and The reactance varies with output power network 9 and the auxiliary amplification path composed of the output offset line 11, between the input terminal of the auxiliary amplifier PA4 and the output terminal of the electric bridge, and between the output terminal of the auxiliary amplifier PA4 and the reactance varies with output power unit 9, And the OFFSET compensation microstrip line connected between the reactance varying with output power unit 9 and the power combining unit 4 . Among them, the OFFSET line 6 mainly plays the role of phase alignment with the main channel, and the OFFSET line 11 mainly completes impedance matching and improves the off-impedance when PA4 is cut off.

By reasonably selecting the lengths of OFFSET lines 6, 7, 10, and 11 and the phase characteristics of the additional phase-shifting network 8 and the network 9 whose reactance varies with output power, the phase alignment of the main amplification path and the auxiliary amplification path can be realized, and the phase difference can be offset The main channel and the auxiliary channel signals are synthesized into one signal and then output by the combining unit 4.

In the usual design, the auxiliary power amplifier PA4 needs to pass a suitable OFFSET 11 impedance line to make its off impedance close to the open state at the junction point, as shown in Figure 5, so that the impedance of the main amplifier path and the auxiliary amplifier path at the junction point is at the output of the power amplifier. The conditions of large and small signals are basically the same, that is, the standing wave ratio of the front and rear is 1:1. At this time, the saturated power of the symmetrical Doherty power tube and the impedance of the maximum efficiency point need to meet the impedance relationship of the standing wave ratio of 2:1.

A power amplifier circuit, a power amplifier device, and a matching method thereof proposed in an optional embodiment of the present invention, by adding a reactance-according to output power change network 9 behind the auxiliary power amplifier PA4, the closing impedance of the closing point is properly deviated from the open-circuit state, so that when the main When the power amplifier PA3 works in the small-signal high-efficiency state, the auxiliary power amplifier PA4 and the reactance network 9 will introduce a certain inductive or capacitive impedance at the junction point as shown in Figure 6. Controlling the reactance value at this point can reduce the main The impedance of the combining point when the power amplifier works with small signal and high efficiency.

However, when the main power amplifier PA3 is working at high power, due to the load-drawing effect of the auxiliary power amplifier PA4 and the reactance network 9 as the output power changes, the parallel impedance of the auxiliary amplifier PA4 at the junction point will be transformed between the impedance value of the cut-off state and the impedance value of the high-power state. The result is shown in Figure 7. Here, the load value of the capacitive load cut-off state is used as an example. At this time, the combined point is at the impedance value corresponding to the maximum output power and the low power condition. Because the auxiliary power amplifier PA4 and the reactance change with the output power The VSWR of the combined point impedance value caused by the decrease of the combined point impedance caused by the network 9 will increase, and the corresponding standing wave ratio value corresponding to the maximum output power of the power tube of the Doherty main amplifier and the maximum output efficiency impedance can be increased, so that the auxiliary After the expansion of the main power amplifier VSWR range caused by the power amplifier load modulation, it can meet the requirement that the relationship between the unpaired impedance VSWR ratio is greater than 2:1, so while ensuring the saturation power and efficiency, the application range of the peak-to-average ratio of the symmetrical DOHERTY power amplifier circuit is expanded. , at the same time, because the reactance of the network 9 can be adjusted according to the change of the reactance with the output power, the inductive or capacitive reactance can be flexibly introduced, so that when the signal is small, it is equivalent to equivalently connecting the inductor or capacitor to the ground in the output combiner unit, which can The initial phase of the small signal output is additionally advanced or lagged by a certain angle, and when the power amplifier outputs a large signal, the parallel reactance disappears due to the load pulling effect of the auxiliary power amplifier PA4 and the reactance network 9 that changes with the output power, and the previously added phase shift angle Also along with eliminating as shown in Figure 8, the reactance that is connected with the auxiliary power amplifier PA4 can be changed with the output power through a reasonable design network 9, which can make the phase shift angle opposite to the AM-PM characteristic of the usual DOHERTY power amplifier (as shown in Figure 9), A certain degree of mutual cancellation between the two can improve the AM-PM distortion of the entire power amplifier, thereby improving the linearity index of the power amplifier. After the embodiment, the variation range of the AM-PM characteristic of the power amplifier with the power of the power amplifier can be reduced from 0-0.3 (radian) to 0.22-0.35. The reduction of the variation range of AM-PM indicates that the AM-PM characteristic has been improved.

Fig. 4 is the power amplifier DOHERTY power amplifier circuit schematic diagram (two) according to the embodiment of the present invention, as shown in Fig. 4:

Power distribution unit 1, additional phase shifting network 8, 50 ohm microstrip line OFFSET 7, main amplifier PA3, 50 ohm microstrip line OFFSET 10, 50 ohm 1/4 wavelength microstrip line 5 constitute the main amplification path.

50 ohm microstrip line OFFSET 6. Auxiliary amplifier PA4, reactance varying with output power network 9, 50 ohm microstrip line OFFSET 11 constitutes an auxiliary amplification path. The main amplifying path and the auxiliary amplifying path are respectively connected with the power distribution unit 1 and the power combining unit 4 to form a 50 ohm 2-way symmetrical Doherty circuit.

The power distribution unit 1 is composed of a bridge and its peripheral circuits. It should be noted that the bridge in this example can be a bridge of 3dB, 5dB or other specifications, which is not limited here. For the convenience of description, in this example, only The bridge is a 3dB bridge as an example for illustration. The input terminal of the 3dB electric bridge is connected with the input signal, and the two output ends of the 3dB electric bridge are respectively connected with the additional phase-shifting network 8 and the OFFSET line 6 of the auxiliary amplifying unit 3 .

The additional phase-shifting network 8 in this example is formed by a section of microstrip line. It should be noted that this network can also be composed of an LC phase-shifting network composed of an inductor and a capacitor or a capacitor, and an RC phase-shifting network composed of a resistor. The phase characteristics need to be the same as the phase shift characteristics of the network 9 whose reactance varies with the output power, and the specific form is not limited here. The network is connected to the main amplifier PA3 through OFFSET 7, and the input terminal of the auxiliary amplifier PA4 is connected to the output terminal of the 3dB bridge They are connected through OFFSET 6, the output terminal of the auxiliary amplifier amplifier PA4 is connected to the combined output unit 4 through the reactance varying with output power network 9, and the output OFFSET 11, when the DOHERTY circuit is working, the reactance varies with the output power network 9 and the auxiliary power amplifier unit 4 change the impedance of the junction point (point P in the accompanying drawings) along with the auxiliary power amplifier PA4 operating state change and output power change. In this example, the reactance varies with the output power. The network 9 is formed by a suitable electrical length In other cases, it can also be composed of voltage-controlled varactor diodes or other controlled variable reactance circuits.

In this example, adjusting the length of the 50 ohm microstrip line of the power change network 9 connected to the auxiliary amplifier PA4 can make the power tube turn-off impedance of the auxiliary amplifier PA4 present a capacitive reactance at the junction point, and an initial -12° Phase shift. At this time, the impedance relationship between the saturated power point and the maximum efficiency point of the main power amplifier PA3 power tube satisfies the asymmetric ratio relationship of 2.5:1, which can better meet the peak-to-average ratio requirement of about 8dB. Since the main power amplifier PA3 and the auxiliary power amplifier PA4 both use the same power tube and the same circuit structure, this circuit expands the application range of the symmetrical DOHERTY in peak-to-average ratio (PAR>6dB), and the corresponding initial phase shift can compensate the circuit AM to a certain extent -PM distortion, thereby improving the linearity index of the circuit.

For a power amplifying device provided in an optional embodiment of the present invention, the circuit structure and principle of the power amplifying circuit can be referred to above, and will not be repeated here. Due to the above-mentioned power amplifier circuit, the output power and efficiency are improved, the adaptability of the power amplifier circuit to the peak-to-average ratio signal is expanded, and the AM-PM characteristics are improved to a certain extent, and the linearity index of the Doherty power amplifier is improved.

The above-mentioned power amplifier circuit, power amplifier device and its design method, by adding additional phase-shifting network and reactance change network with output power in the main power amplifier unit and auxiliary power amplifier unit respectively, control the impedance characteristic when the power tube of the auxiliary amplifier power tube of the junction point is cut off. The relationship between the saturation power of the main power amplifier and the impedance of the maximum efficiency point is improved, and the application range of the symmetrical DOHERTY power amplifier circuit is expanded, so that the symmetrical DOHERTY power amplifier circuit can adapt to higher peak-to-average ratio requirements.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases, in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (22)

1. a symmetrical Doherty Doherty power amplifier device, it is characterised in that including:

Power distributing unit, for input signal is assigned as the multiple signals of predetermined phase difference, and is respectively outputted to Main amplification channel and auxiliary amplification channel；

Main amplification channel, including: added phase shift network, micro-with the main amplification channel that described added phase shift network is connected Band wire, the main amplifier being connected with described main amplification channel microstrip line, for by described added phase shift network, with And main amplification channel microstrip line carries out the phase alignment of main amplification channel signal and auxiliary amplification channel signal, by institute State main amplifier and main amplification channel signal is carried out power amplification；

At least one assists amplification channel, including: auxiliary amplification channel microstrip line is micro-with described auxiliary amplification channel Booster amplifier, the reactance that is connected with described booster amplifier that band wire is connected change network with output, are used for The phase place pair assisting amplification channel signal with main amplification channel signal is carried out by described auxiliary amplification channel microstrip line Together, by described booster amplifier, auxiliary amplification channel signal is carried out power amplification, high at main amplifier small-signal Under efficiency duty, by described reactance with output change network reduce described booster amplifier cut-off time Close the shutoff impedance of waypoint to predetermined value；

Power combing unit, for closing the letter that described main amplification channel and described auxiliary amplification channel are inputted by waypoint Number synthesis one road signal after export.

Device the most according to claim 1, it is characterised in that the phase characteristic of described added phase shift network and described electricity The anti-phase characteristic with output change network is identical.

Device the most according to claim 1, it is characterised in that described added phase shift network is used for: offset by reactance with Output change phase contrast caused by network.

Device the most according to claim 1, it is characterised in that described main amplification channel microstrip line is used for: offset described Predetermined phase is poor and by the phase contrast caused by described auxiliary amplification channel microstrip line and booster amplifier.

Device the most according to claim 1, it is characterised in that described auxiliary amplification channel microstrip line is used for, offset by Phase contrast caused by described main amplification channel microstrip line and main amplifier.

Device the most according to claim 1, it is characterised in that described reactance is used for output change network: Under main amplifier small-signal efficiency operation state, by controlling its emotional resistance in conjunction waypoint caused or capacitive The value of impedance, reduces described shutoff impedance to predetermined value.

Device the most according to claim 1, it is characterised in that described added phase shift network is: biasing microstrip line, electricity Electrification holds LC phase-shift network or resistance capacitance RC phase-shift network.

Device the most according to claim 1, it is characterised in that described reactance with output change network is: biasing Microstrip line, varactor or variable reactance circuit.

Device the most according to claim 1, it is characterised in that described main amplification channel microstrip line includes: attached with described Add phase-shift network be connected first biasing microstrip line, be connected with described main amplifier outfan second bias microstrip line, And bias, with described second, the 1/4 wave microstrip line that microstrip line is connected.

Device the most according to claim 1, it is characterised in that described auxiliary amplification channel microstrip line includes: with described The 3rd biasing microstrip line that power distributing unit is connected and being connected with output change network with described reactance 4th biasing microstrip line.

11. 1 kinds of symmetrical Doherty DOHERTY power amplifiers, it is characterised in that including: main power amplification passage and one Individual or multiple auxiliary power amplification channels, wherein, described main power amplification passage includes: be sequentially connected in series First compensated microstrip line, main power amplifier and the second compensated microstrip line；Each described auxiliary power amplification channel bag Include: the 3rd compensated microstrip line, auxiliary power amplifier and the 4th compensated microstrip line being sequentially connected in series, wherein, Described DOHERTY power amplifier also includes:

Reactance, with changed power network, is arranged on described auxiliary power amplification channel, and wherein, described reactance is with merit Rate change network is for arranging the first predetermined threshold by the shutoff impedance of described auxiliary power amplifier；

Added phase shift network, is arranged on described main power amplification passage, and wherein, described added phase shift network is used for Making first phase difference poor with second phase identical, wherein, described first phase is described main power amplification passage Input signal and the input of described auxiliary power amplification channel that input receives receive between input signal Phase contrast, described second phase be described main power amplification passage outfan output output signal auxiliary with described Phase contrast between the output signal of the outfan output of assist rate amplification channel.

12. DOHERTY power amplifiers according to claim 11, it is characterised in that described reactance is with changed power Network is connected between described auxiliary power amplifier and described 4th compensated microstrip line, or, described reactance is with merit Rate change network is connected between described 4th compensated microstrip line and the outfan of described auxiliary power amplification channel.

13. DOHERTY power amplifiers according to claim 11, it is characterised in that described added phase shift network is even It is connected between input and described first compensated microstrip line of described main power amplification passage, or, described additional shifting Phase network is connected between described first compensated microstrip line and described main power amplifier.

14. DOHERTY power amplifiers according to claim 11, it is characterised in that described added phase shift network Phase and frequency characteristic is identical with the phase and frequency characteristic of changed power network with described reactance.

15. DOHERTY power amplifiers according to claim 11, it is characterised in that described reactance is with changed power Network, described added phase shift network, described first compensated microstrip line, described second compensated microstrip line, the described 3rd Compensated microstrip line and described 4th compensated microstrip line are provided commonly for so that poor and described second phase of described first phase Potential difference is identical.

16. DOHERTY power amplifiers according to claim 11, it is characterised in that described 4th compensated microstrip line For making the impedance of described auxiliary power amplification channel be the second predetermined threshold and described auxiliary power being amplified The shutoff impedance of device is adjusted to the 3rd predetermined threshold, and wherein, described 3rd predetermined threshold is more than described first predetermined threshold Value.

17. DOHERTY power amplifiers according to claim 11, it is characterised in that described DOHERTY power Amplifier also includes:

For distributing the power distributing unit of power, wherein, the input of described power distributing unit is used for receiving defeated Entering signal, the first outfan of described power distributing unit is connected to the input of described added phase shift network, described Second outfan of power distributing unit is connected to described 3rd compensated microstrip line；

For synthesizing the power combing unit of power, wherein, the first input end of described power combing unit is by micro- Band impedance transformation line is connected with described second compensated microstrip line, and the second input of described power combing unit is with described 4th compensated microstrip line connects, or the second input of described power combing unit and described reactance are with changed power Network connects.

18. DOHERTY power amplifiers according to claim 17, it is characterised in that described power distributing unit will Described input signal is assigned as the multiple signals that phase contrast is 90 °, and described multiple signals are separately input into institute State main power amplification passage and one or more auxiliary power amplification channel.

19. DOHERTY power amplifiers according to claim 18, it is characterised in that every road of described multiple signals The power of signal is the 1/N of described input signal power, and wherein, N is the quantity of described multiple signals.

20. DOHERTY power amplifiers according to claim 17, it is characterised in that described power distributing unit bag Include electric bridge.

21. DOHERTY power amplifiers according to claim 11, it is characterised in that described added phase shift network packet Include at least one of:

Microstrip line；

Inductance and the LC phase-shift network of electric capacity composition；

Electric capacity and the RC phase-shift network of resistance composition.

22. DOHERTY power amplifiers according to claim 11, it is characterised in that described reactance is with changed power Network includes at least one of:

Microstrip line；

Varactor；

Reactance circuit.