WO2024067147A1

WO2024067147A1 - Power amplifier

Info

Publication number: WO2024067147A1
Application number: PCT/CN2023/118933
Authority: WO
Inventors: 谈建国; 丁冲; 余敏德; 魏伟伟; 秦天银
Original assignee: 中兴通讯股份有限公司
Priority date: 2022-09-29
Filing date: 2023-09-14
Publication date: 2024-04-04
Also published as: CN117833831A

Abstract

Provided in the embodiments of the present disclosure is a power amplifier, comprising: a coupler and a harmonic generation network, the coupler being connected to the harmonic generation network, wherein the coupler is configured to couple a portion of input signals among input signals of the power amplifier, so as to obtain a fundamental-wave signal, and output the fundamental-wave signal to the harmonic generation network; and the harmonic generation network is configured to generate a harmonic component on the basis of the fundamental-wave signal, and input the harmonic component into a power-amplifier input circuit of the power amplifier.

Description

A power amplifier

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is based on Chinese patent application 202211219421.4 filed on September 29, 2022, with the invention name “A Power Amplifier”, and claims the priority of the patent application, and all the contents disclosed therein are incorporated into the present disclosure by reference.

Technical Field

The embodiments of the present disclosure relate to the field of signal processing, and in particular, to a power amplifier.

Background technique

When the working bandwidth of the power amplifier exceeds one octave, there must be a situation where the second harmonic frequency of some working frequency bands falls within the overall working bandwidth. In this case, the second harmonic impedance required for the corresponding working frequency band cannot be achieved through network matching, and because its impedance value is equal to a fundamental impedance value within the working frequency band, it has a large real part. This second harmonic impedance condition will greatly affect the efficiency index of the cross-octave power amplifier. Since this problem cannot be solved by using only a passive matching network, similar to active load modulation, second harmonic active load modulation can be introduced to change the second harmonic impedance to improve the efficiency index of the corresponding frequency band. In the related technology, the second harmonic component is injected into the output network of the power amplifier to perform second harmonic active load modulation. However, the second harmonic loading network used will inevitably affect the matching network of the original power amplifier, resulting in the difficulty of second harmonic active load modulation technology being set in an ultra-wideband power amplifier.

In view of the problem in the related art that injecting a second harmonic component into the output network of the power amplifier for second harmonic active load modulation is difficult to be set in an ultra-wideband power amplifier, no solution has been proposed yet.

Summary of the invention

The embodiments of the present disclosure provide a power amplifier to at least solve the problem in the related art that it is difficult to inject a second harmonic component into the output network of the power amplifier to perform second harmonic active load modulation in an ultra-wideband power amplifier.

According to an embodiment of the present disclosure, a power amplifier is provided, comprising: a coupler and a harmonic generation network, wherein the coupler is connected to the harmonic generation network, wherein:

A coupler is configured to couple a portion of the input signal from the input signal of the power amplifier to obtain a fundamental wave signal, and output the fundamental wave signal to the harmonic generation network;

The harmonic generation network is configured to generate harmonic components based on the fundamental wave signal and input the harmonic components into a power amplifier input circuit of the power amplifier.

The power amplifier of the embodiment of the present disclosure includes: a power amplifier, including: a coupler and a harmonic generating network, the coupler is connected to the harmonic generating network, wherein the coupler is configured to couple out a part of the input signal from the input signal of the power amplifier to obtain a fundamental signal, and output it to the harmonic generating network; the harmonic generating network is configured to generate harmonic components based on the fundamental signal, and input the harmonic components into the power amplifier input circuit of the power amplifier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of a power amplifier according to an embodiment of the present disclosure;

FIG2 is a block diagram of a power amplifier according to an exemplary embodiment of the present disclosure;

FIG3 is a second block diagram of a power amplifier according to an exemplary embodiment of the present disclosure;

FIG4 is a block diagram of a power amplifier according to an exemplary embodiment of the present disclosure;

FIG5 is a block diagram of a power amplifier based on harmonic injection of an LMBA architecture according to an exemplary embodiment of the present disclosure;

FIG6 is a functional block diagram of a coupler according to an exemplary embodiment of the present disclosure;

FIG7 is a schematic block diagram of a harmonic generation network according to an exemplary embodiment of the present disclosure;

FIG8 is a result block diagram of a circuit matching network IMN according to this embodiment;

FIG9 is a schematic diagram showing the effect of the phase and power of the loaded second harmonic on the performance of the power amplifier according to the present embodiment;

FIG10 is a schematic diagram of impedance distribution of a cross-octave power amplifier matching according to this embodiment;

FIG11 is a second block diagram of a power amplifier based on harmonic injection of an LMBA architecture according to an exemplary embodiment of the present disclosure;

FIG12 is a block diagram of a power amplifier based on harmonic injection of an LMBA architecture according to an exemplary embodiment of the present disclosure;

FIG. 13 is a block diagram of a power amplifier with harmonic injection based on a DEPA architecture according to this embodiment.

Detailed ways

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and in combination with the embodiments.

It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are set to distinguish similar objects, and are not necessarily set to describe a specific order or sequence.

An embodiment of the present disclosure provides a power amplifier. FIG1 is a block diagram of a power amplifier according to an embodiment of the present disclosure. As shown in FIG1 , the power amplifier includes: a coupler and a harmonic generating network. The coupler is connected to the harmonic generating network, wherein the coupler is configured to couple a portion of the input signal from the input signal of the power amplifier to obtain a fundamental signal, and output the fundamental signal to the harmonic generating network; the harmonic generating network is configured to generate a harmonic component based on the fundamental signal, and input the harmonic component into a power amplifier input circuit of the power amplifier.

Figure 2 is a block diagram of a power amplifier according to an exemplary embodiment of the present disclosure. As shown in Figure 2, the power amplifier also includes: a signal processing device, a plurality of RF channels and a first bridge, wherein the signal processing device is connected to the plurality of RF channels, and the plurality of RF channels are connected to the first bridge; at least one of the plurality of RF channels is provided with a harmonic generating network, a coupler is connected to the signal processing device, and each RF channel is provided with a power amplifier input circuit; the signal processing device is configured to divide an input signal into a plurality of input signals and input them into corresponding RF channels, and one input signal is input into one RF channel; the first bridge is configured to synthesize the multi-path signals of the plurality of RF channels into an output signal.

Figure 3 is a second block diagram of a power amplifier according to an exemplary embodiment of the present disclosure. As shown in Figure 3, the power amplifier input circuit includes: a power amplifier tube and a circuit matching network, wherein each RF channel is provided with a connected circuit matching network and a power amplifier tube, the signal processing device is respectively connected to a plurality of the circuit matching networks, and a plurality of the power amplifier tubes are connected to the first bridge, wherein each of the circuit matching networks is configured to match the input of the signal processing device and the power amplifier tube; and each of the power amplifier tubes is configured to amplify the input signal on the RF channel where it is located.

In one embodiment, the circuit matching network is configured to combine the input signal with the harmonic signal generated by the harmonic generating network and output them to the input end of the power amplifier tube; or to output the input signal to the input end of the power amplifier tube.

As shown in FIG. 3 , one end of the coupler is connected to the output end of the signal processing device, and the remaining ports are connected to the harmonic generating network and the circuit matching network respectively.

Figure 4 is a block diagram of the power amplifier according to an exemplary embodiment of the present disclosure. As shown in Figure 4, one end of the coupler is connected to the input end of the signal processing device, and the remaining ports are respectively connected to the harmonic generating network and the circuit matching network. The coupler is configured to select a partial frequency signal of the input signal to obtain a fundamental signal.

In this embodiment, the above-mentioned signal processing device may be a power divider or a second bridge.

The present embodiment is described below by taking the signal processing device as a power divider as an example.

The architecture of the load-modulated balanced power amplifier (LMBA) is that the input end divides the signal into multiple signals and transmits them to each RF channel through a bridge or a power divider, and then synthesizes them through a bridge at the output end. Figure 5 is a block diagram of a power amplifier with harmonic injection based on the LMBA architecture according to an exemplary embodiment of the present disclosure, as shown in Figure 5, and in order to improve and expand the limitation of the working frequency band of the LMBA, this embodiment introduces a harmonic generation network in the control branch to adjust the working state of the LMBA and improve its working performance. The power divider is used to divide the input signal into two or more channels to each RF channel; the coupler is used to couple a part of the signal into the harmonic generation network; the harmonic generation network: to generate harmonic components with specific amplitude and phase, and inject them into the control branch; the power amplifier tube is used to amplify the signal, and the bridge is used to synthesize or power distribute the signal (where the branch with the harmonic generation network is the control branch); IMN1/IMN2/IMN3 are circuit matching networks.

In broadband power amplifier design, the performance of some frequency bands will be far lower than the theoretical performance. As shown in the figure, by injecting harmonics at the input of the LMBA, the amplitude and phase of the harmonics are modulated at the output, which greatly improves the output power and efficiency of the LMBA power amplifier and significantly expands its operating bandwidth.

FIG6 is a principle block diagram of a coupler according to an exemplary embodiment of the present disclosure. As shown in FIG6 , the coupler includes: an input terminal 201, a through terminal 202, and a coupling terminal 203, wherein the fundamental wave signal is coupled from the input terminal 201 to the coupling terminal 203, and the fundamental wave signal is obtained by directing from the input terminal 201 to the through terminal 202 in the full frequency band. The coupling terminal of the coupler has a frequency selection characteristic: only part of the frequency can be coupled from the 201 port to the coupling 203 port; and the full frequency band is directly passed from the 201 port to the 202 port.

FIG7 is a principle block diagram of a harmonic generation network according to an exemplary embodiment of the present disclosure. As shown in FIG7 , the harmonic generation network includes a nonlinear circuit, a bandpass filter, a phase shifter and a harmonic gain amplifier connected in sequence. The harmonic gain amplifier is connected to the circuit matching network, wherein the nonlinear circuit is configured to perform nonlinear processing on the fundamental signal to generate multiple harmonic components; the bandpass filter is configured to select a target harmonic component from the multiple harmonic components; the phase shifter is configured to adjust the phase of the target harmonic component to obtain a harmonic signal; the harmonic gain amplifier is configured to amplify the harmonic signal and input it to the input end of the power amplifier tube. The coupled fundamental signal is input into a nonlinear circuit to generate rich harmonic components; the second and third harmonics are then selected through a bandpass filter; the residual signal is passed through a phase shifter to adjust the phase of the harmonic component (the shifted phase depends on the phase requirement of the harmonic injection); finally, the harmonic signal is amplified by the harmonic gain amplifier and input into the power amplifier input circuit.

FIG8 is a result block diagram of the circuit matching network IMN according to this embodiment. As shown in FIG8, the main function of IMN is to match the power divider at the input end with the input of the power amplifier tube, and has the function of connecting the harmonic generation network. Mode 1: When the low frequency band f1＜f0＜f2, the function of IMN is to combine the input signal and the harmonic signal and output them to the input end of the power amplifier tube; Mode 2: When the low frequency band f2＜f0＜f3, the function of IMN is to make the input signal as high as possible output to the input end of the power amplifier tube.

As shown in Figure 5, the second harmonic active load loading scheme, its second harmonic active load modulation process follows the same rule as the fundamental load modulation, that is, the impedance at the coupler port corresponding to the balanced power amplifier can be calculated by the following formula:

In the formula, _Z0 is the original port impedance of the coupler, _Ipk and _Iba are the output currents of the peak control amplifier and the single main amplifier, respectively, and is the current phase difference between the peak amplifier and the main amplifier at the relative port. It can be seen from the above formula that adjusting the phase and amplitude of the second harmonic current from the peak amplifier branch can perform second harmonic active load modulation on the impedance of the output port of the main amplifier. After transformation by the matching network, this modulation effect can be transmitted to the transistor (amplifier) port, thereby changing the performance of the main amplifier.

FIG9 is a schematic diagram of the effect of the phase and power of the loaded second harmonic on the performance of the power amplifier according to the present embodiment. As shown in FIG9 , for a high back-off efficiency power amplifier across octaves, it is unrealistic to enable the harmonic active load modulation technology in the entire operating frequency band. Outside the operating frequency band, the functions of active devices and circuits such as couplers used are not the same as those within the operating frequency band, which may render the harmonic active load modulation ineffective. In addition, the harmonic impedance outside the operating frequency band is likely to present a pure reactance characteristic, and harmonic active load modulation cannot be used for harmonic impedances with such characteristics. In view of this situation, harmonic impedance matching and harmonic active load modulation techniques can be used in different operating frequency bands, respectively, to globally optimize the performance of the designed power amplifier according to the characteristics of different operating frequency bands.

FIG10 is a schematic diagram of impedance distribution of a cross-octave power amplifier according to the present embodiment. As shown in FIG10 , the impedance solution region of the current source end face for the double-octave expansion is given. In order to ensure that the cross-octave power amplifier has a certain amount of output power, the fundamental impedance of each frequency point should converge into one region, that is, the real part of the fundamental impedance is within a limited range. As shown in FIG10 (a), when the frequency point of band 1 is working, when the power amplifier input end is not loaded with harmonics, the second or third harmonic impedance of band 1 is the position of band 3, which is bound to reduce the working efficiency of band 1. Therefore, when band 1 is working in the low frequency band, the second or third harmonic impedance of band 1 is located in the new impedance region by means of harmonic injection, as shown in FIG10 (b). In this way, when band 1 is working, the harmonic impedance of the power amplifier at the current source end face is pulled with the change of the injected harmonic signal, thereby improving the working efficiency of band 1.

In one embodiment, the multiple power amplifier tubes include one or more main power amplifier tubes and one or more peak power amplifier tubes, as shown in Figure 5, the harmonic generating network is arranged on the radio frequency channel where the one or more main power amplifier tubes are located, the power amplifier tube 3 is the main power amplifier tube, and the harmonic generating network is arranged on the radio frequency channel where the power amplifier tube 3 is located.

Figure 11 is a second block diagram of a power amplifier with harmonic injection based on an LMBA architecture according to an exemplary embodiment of the present disclosure. As shown in Figure 11, power amplifier tube 1 and power amplifier tube 2 are peak power amplifier tubes, and the harmonic generating network is arranged on the RF channel where the one or more peak power amplifier tubes are located, that is, on the RF channel where power amplifier tube 1 and power amplifier tube 2 are located.

FIG12 is a block diagram of a power amplifier based on harmonic injection of an LMBA architecture according to an exemplary embodiment of the present disclosure. As shown in FIG12 , relative to FIG11 , the placement position of the coupler places the coupler input end before the power divider. Similar to the coupling loading position in FIG5 , it can also be placed at the front end, even at the front end of the pre-stage driver amplifier.

When the structure is not an LMBA architecture, such as a distributed efficient power amplifier (DEPA) architecture, the cross-octave power amplifier can also be processed by the above method to perform low-frequency harmonic injection processing. Figure 13 is a block diagram of a power amplifier based on harmonic injection of the DEPA architecture according to this embodiment. As shown in Figure 13, the main power amplifier end signal of the harmonic injection is injected, and the similar signal coupling position can be the front input end of the module; the harmonic injection branch can also be changed to the peak branch.

For LMBA amplifiers that span octaves, harmonic injection is used to improve the degree of harmonic impedance mismatch and enhance the amplifier efficiency in the low-frequency band.

For the amplifier architecture with high efficiency across octaves, such as the LMBA architecture, when working in the low frequency band f1, its harmonics may be between the frequency bands f2-f3. Since the LMBA can work between f1-f3, the high-order harmonic impedance of f1 is the impedance between f2-f3 that satisfies the n*f1 frequency point. This impedance conflicts with the high-efficiency working state of the amplifier, and thus reduces the efficiency at the f1 frequency band. Therefore, by injecting harmonic components, the efficiency at the low frequency band f1 can be improved.

Compared with harmonic injection at the output of the power amplifier, the advantages of injecting harmonics at the input are as follows: when used in an inter-octave frequency band, the coupler is bidirectional. When the harmonic components generated by the frequency doubler can be coupled to the signal path, then when working in the high frequency band, its signal can also be coupled to the harmonic generation network. In this way, the harmonic generation network will additionally lose energy and reduce and deteriorate the efficiency and linearity of the high frequency band. On the other hand, under high power input, the devices used in the harmonic generation network need to meet the high power working requirements, which puts higher requirements on the devices of the harmonic generation network and directly increases the product cost.

The amplifiers in the amplifier architecture are divided into two categories: the main amplifiers work in both low-power and high-power states, and the peak amplifiers work only in high-power states; harmonic injection into the main amplifier helps to perform load harmonic modulation on the output of the amplifier at both low-power and high-power states; while harmonic injection into the peak amplifier only performs load modulation on the output of the amplifier at high-power states. The choice of a certain mode depends on which power area and which amplifier tube efficiency needs to be improved during the load modulation process: for example, through reasonable circuit design, the main amplifier can have high efficiency in both low-power and high-power states, and only the peak amplifier has deteriorated efficiency in the low-frequency band. At this time, only harmonic injection into the peak amplifier is needed to effectively improve the efficiency of the peak amplifier.

For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

Obviously, those skilled in the art should understand that the above modules or steps of the present disclosure can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present disclosure is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

A power amplifier comprises: a coupler and a harmonic generation network, wherein the coupler is connected to the harmonic generation network, wherein:

The coupler is configured to couple a portion of the input signal from the input signal of the power amplifier to obtain a fundamental wave signal, and output the fundamental wave signal to the harmonic generation network;

The harmonic generation network is configured to generate harmonic components based on the fundamental wave signal and input the harmonic components into a power amplifier input circuit of the power amplifier.
The power amplifier according to claim 1, wherein the power amplifier further comprises: a signal processing device, a plurality of RF channels and a first bridge, wherein the signal processing device is connected to the plurality of RF channels, and the plurality of RF channels are connected to the first bridge; at least one of the plurality of RF channels is provided with a harmonic generating network, the coupler is connected to the signal processing device, and each RF channel is provided with a power amplifier input circuit;

The signal processing device is configured to divide the input signal into multiple input signals and input them into corresponding radio frequency channels, and one input signal is input into one radio frequency channel;

The first bridge is configured to synthesize the multi-path signals of the multiple radio frequency channels into an output signal.
The power amplifier according to claim 2, wherein the power amplifier input circuit comprises: a power amplifier tube and a circuit matching network, wherein each RF channel is provided with a connected circuit matching network and a power amplifier tube, the signal processing device is respectively connected to a plurality of the circuit matching networks, and a plurality of the power amplifier tubes are connected to the first bridge, wherein,

Each of the circuit matching networks is configured to match the input of the signal processing device with the input of the power amplifier tube;

Each of the power amplifier tubes is configured to amplify the input signal on the radio frequency channel.
The power amplifier according to claim 3, wherein:

The circuit matching network is configured to combine the input signal with the harmonic signal generated by the harmonic generation network and output the combined signals to the input end of the power amplifier tube; or to output the input signal to the input end of the power amplifier tube.
The power amplifier according to claim 3, wherein the plurality of power amplifier tubes include one or more main power amplifier tubes and one or more peak power amplifier tubes, and the harmonic generating network is arranged on the radio frequency channel where the one or more main power amplifier tubes are located; or, the harmonic generating network is arranged on the radio frequency channel where the one or more peak power amplifier tubes are located.
The power amplifier according to claim 2, wherein one end of the coupler is connected to the output end of the signal processing device, and the remaining ports are respectively connected to the harmonic generating network and the circuit matching network.
The power amplifier according to claim 2, wherein one end of the coupler is connected to the input end of the signal processing device, and the remaining ports are respectively connected to the harmonic generating network and the circuit matching network.
The power amplifier according to claim 6 or 7, wherein:

The coupler comprises: an input end, a through end, and a coupling end, wherein the fundamental wave signal is coupled from the input end to the coupling end, and is directly passed from the input end to the through end in the full frequency band to obtain the fundamental wave signal.
The power amplifier according to claim 2, wherein the harmonic generation network comprises a nonlinear circuit, a bandpass filter, a phase shifter and a harmonic gain amplifier connected in sequence, and the harmonic gain amplifier is connected to the circuit matching network, wherein:

The nonlinear circuit is configured to perform nonlinear processing on the fundamental wave signal to generate a plurality of harmonic components;

The bandpass filter is configured to select a target harmonic component from the plurality of harmonic components;

The phase shifter is configured to adjust the phase of the target harmonic component to obtain a harmonic signal;

The harmonic gain amplifier is configured to amplify the harmonic signal and then input it into the input end of the power amplifier tube.
According to the power amplifier according to any one of claims 2 to 6 and 8 to 9, the signal processing device is a power divider or a second bridge.