Active harmonic injection broadband high efficiency power amplifier based on fundamental recovery and single-ended driving

Abstract

The application belongs to the technical field of microwave and radio frequency power amplifier, and discloses an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recycling and single-end driving, wherein the radio frequency signal is distributed to a main amplifier and an auxiliary amplifier through an input power divider, a harmonic separation network is arranged at the output end of the auxiliary amplifier, the second harmonic generated by the auxiliary amplifier is fed into the drain of the main amplifier after phase adjustment through the harmonic injection network, and the fundamental wave power generated by the auxiliary amplifier is delivered to an output power combiner through a fundamental wave power recycling branch, and the fundamental wave power of the main amplifier is combined in phase to be output to a load. The power amplifier can simplify the system complexity, effectively suppress the nonlinear distortion and parasitic loss without the premise of double radio frequency sources or frequency multipliers, greatly improve the total output power and working efficiency, and realize the compactness and low cost of the broadband high-efficiency high-power transmitter.

Description

Technical Field

[0001] This invention belongs to the field of microwave and radio frequency power amplifier technology, and particularly relates to an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive. Background Technology

[0002] With the continuous development of wireless communication systems, the performance requirements for RF power amplifiers, as core components of wireless transmitters, are constantly increasing, demanding wider bandwidth and higher efficiency. Continuous-mode power amplifiers, such as continuous Class B / J and continuous Class F / inverse Class F amplifiers, have become important technical means to achieve broadband and efficient operation by expanding the impedance design space. To overcome the performance limitations of traditional passive matching networks, active harmonic injection technology has been proposed and continuously studied. This technology achieves precise waveform shaping by injecting harmonic signals into the power amplifier. Related research has covered multiple directions, including ultra-wideband operation, linearity optimization, and continuous operating mode expansion, which can break through the efficiency limits of traditional continuous-mode power amplifiers and has significant performance improvement potential.

[0003] Traditional continuous-mode power amplifiers heavily rely on complex passive harmonic control circuits, which not only increase circuit size and parasitic losses but also easily induce nonlinear distortion. Meanwhile, broadband passive matching networks typically require performance trade-offs when handling high- and low-frequency impedances, making it difficult to achieve optimal efficiency termination across the entire frequency band. Existing active harmonic injection circuits still face two major technical bottlenecks in engineering applications: first, the system architecture is complex, with current solutions often relying on dual RF source drives or frequency multipliers to generate harmonic signals. The frequency multipliers suffer from nonlinear conversion losses, significantly increasing the complexity and cost of the transmitter system; second, there is severe fundamental energy waste, with the auxiliary power amplifier used only as a harmonic signal generator. A large amount of high-energy fundamental components generated are blocked by the filtering network or dissipated in the dummy load, failing to transmit to the final load, resulting in significant energy loss and directly limiting further improvements in the total output power and overall efficiency of the power amplifier system.

[0004] It is evident that in existing broadband high-efficiency power amplifier technologies, passive harmonic control schemes suffer from high circuit complexity, large parasitic losses, and difficulty in achieving optimal efficiency across the entire frequency band. Active harmonic injection schemes, on the other hand, suffer from technical bottlenecks such as complex system drive architecture and significant waste of fundamental energy in the auxiliary power amplifier. Neither approach can simultaneously achieve high efficiency and high power output across a wide frequency band while maintaining control system complexity and cost. Summary of the Invention

[0005] This invention provides an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive. This power amplifier addresses the problems of high circuit complexity, large parasitic losses, and difficulty in achieving optimal full-band efficiency in existing broadband high-efficiency power amplifier technologies using passive harmonic control schemes. It also solves the problems of complex system drive architecture and significant waste of fundamental frequency energy in active harmonic injection schemes. This power amplifier achieves a performance improvement of high efficiency and high power output across a wide frequency band while maintaining control system complexity and cost.

[0006] To achieve the above objectives, the present invention employs the following technical content: An active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive includes an RF input port, an input power divider, a main amplifier circuit, an auxiliary amplifier circuit, a harmonic separation network, a harmonic injection network, and an output power combiner. The radio frequency input port is connected to the input terminal of the input power divider, and the output terminal of the input power divider is connected to the input terminals of the main amplifier circuit and the auxiliary amplifier circuit, respectively. The output terminal of the main amplifier circuit is connected to the first input terminal of the output power combiner. The output terminal of the auxiliary amplifier circuit is connected to the input terminal of the harmonic separation network; The harmonic separation network has two output branches: a second harmonic output branch and a fundamental power recovery branch. The second harmonic output branch is connected to the input terminal of the harmonic injection network, and the output terminal of the harmonic injection network is connected to the drain of the main amplifier in the main amplifier circuit, for injecting the phase-shifted second harmonic into the main amplifier. The fundamental power recovery branch is connected to the second input terminal of the output power combiner, for extracting the fundamental power generated by the auxiliary amplifier circuit and outputting it to the output power combiner. The output power combiner is used to combine the fundamental power output from the main amplifier circuit with the fundamental power output from the fundamental power recovery branch in phase and then output it to the load.

[0007] Furthermore, the main amplifier circuit includes a main amplifier input matching network, a main amplifier, and a main amplifier output matching network; The gate of the main amplifier is connected to the first output terminal of the input power divider through the main amplifier input matching network, the drain of the main amplifier is connected to one end of the main amplifier output matching network, and the other end of the main amplifier output matching network is connected to the first input terminal of the output power combiner. The auxiliary amplifier circuit includes an auxiliary amplifier input matching network and an auxiliary amplifier; the gate of the auxiliary amplifier is connected to the second output terminal of the input power divider through the auxiliary amplifier input matching network, and the drain of the auxiliary amplifier is connected to the input terminal of the harmonic separation network.

[0008] Furthermore, the fundamental power recovery branch is connected in series with an auxiliary amplifier output matching network and a phase offset microstrip line to compensate for the phase difference between the main and auxiliary fundamental signals, so that the two fundamental power signals are superimposed in phase at the output power synthesizer.

[0009] Furthermore, the harmonic separation network adopts a microstrip line network; the microstrip line network includes quarter-wavelength microstrip lines operating at the fundamental frequency and the second harmonic frequency, respectively, to achieve physical isolation and lossless distribution of the fundamental power and second harmonic power output from the drain of the auxiliary amplifier.

[0010] A design method for an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive is provided, for designing the aforementioned active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive, comprising: Introducing voltage distribution ratio coefficient k The drain voltage waveform of the auxiliary amplifier is mathematically reconstructed. Combined with auxiliary amplifier to recover fundamental power P 1f,A , fundamental frequency output power of main amplifier P 1f,M DC power consumption of main amplifier P dc,M and auxiliary amplifier DC power consumption P dc,A Establish a voltage distribution ratio coefficient k The analytical equation for the overall system efficiency; Adjust the bias and matching networks of the main amplifier branch and the auxiliary amplifier branch to adjust the voltage distribution ratio. k Operating within a safe range ensures the waveform shaping effect of the main amplifier while maximizing the overall system efficiency.

[0011] Furthermore, the mathematical reconstruction of the drain voltage waveform of the auxiliary amplifier includes: When the auxiliary amplifier is biased in the Class C operating region, its drain voltage time-domain equation is defined as:

[0012] in, v ds,A (θ) This is the drain voltage of the auxiliary amplifier. θ 1 and θ2 represents the phase offset between the fundamental component and the second harmonic component, respectively; V dd,A This is the drain bias voltage for the auxiliary power amplifier; The fundamental voltage amplitude, Let be the amplitude of the second harmonic voltage, and satisfy:

[0013] in, k The range of values ​​is 0 < k <1.

[0014] Furthermore, the auxiliary amplifier recovers the fundamental power. P 1f,A Based on the fundamental power extracted from the auxiliary amplifier, the specific expression is as follows:

[0015] in, α 1,A The Fourier coefficients of the fundamental current of the auxiliary power amplifier, I max,A This is the maximum drain current of the auxiliary amplifier; The auxiliary power amplifier is used to inject second harmonic power into the main power amplifier. P 2f,A The expression for the second harmonic power is:

[0016] in, α 2,A The Fourier coefficients of the second harmonic current of the auxiliary power amplifier.

[0017] Furthermore, the specific expression of the analytical equation for the overall system efficiency is as follows:

[0018] In the formula, The overall system efficiency; According to the principle of energy conservation, the second harmonic power separated by the auxiliary amplifier satisfies the injection power required for the main amplifier to reconstruct the optimal waveform. .

[0019] Furthermore, when the main amplifier is in continuous operation mode and its output efficiency is at its highest, its various power parameters are set as prerequisite boundary conditions, specifically: The expression for the DC power consumption of the main amplifier is: ; The expression for the fundamental output power of the main amplifier is: ; The expression for the second harmonic injection power required by the main amplifier is: ; in, V dd,M This is the drain bias voltage of the main amplifier. I max,M This is the maximum drain current of the main amplifier.

[0020] A transmitter comprising the aforementioned active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive; The RF signal output terminal of the transmitter is connected to the RF input port of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive. The output terminal of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive is connected to the transmitting load for outputting the amplified RF signal.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive. An input power divider distributes the RF signal to the main amplifier and auxiliary amplifier. A harmonic separation network is set at the output of the auxiliary amplifier, and the second harmonic generated therefrom is phase-adjusted by the harmonic injection network before being fed into the drain of the main amplifier. Simultaneously, the fundamental frequency power generated by the auxiliary amplifier is sent to the output power combiner via a fundamental frequency power recovery branch. This power is then combined in phase with the fundamental frequency power of the main amplifier and output to the load. The harmonic separation network simultaneously achieves harmonic injection and fundamental frequency recovery: on the one hand, the actively injected second harmonic optimizes the drain voltage waveform of the main amplifier, reducing its conduction angle and power consumption, thus approaching optimal efficiency termination across the entire frequency band and eliminating reliance on complex passive harmonic control circuits; on the other hand, it recovers the high-energy fundamental frequency component that would otherwise be wasted by the auxiliary amplifier and participates in power combining, avoiding the problem of fundamental frequency energy dissipation in dummy loads in traditional active solutions. This power amplifier significantly simplifies system complexity, effectively suppresses nonlinear distortion and parasitic losses without requiring dual RF sources or frequency multipliers, and greatly improves total output power and operating efficiency, achieving a compact and low-cost broadband high-efficiency high-power transmitter.

[0022] This invention also provides a design method for an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive. This method introduces a voltage distribution ratio coefficient. k The drain voltage waveform of the auxiliary amplifier is mathematically reconstructed, and combined with the fundamental output power and DC power consumption of the main amplifier, as well as the fundamental power and DC power consumption recovered by the auxiliary amplifier, a system is established that includes... k The system's overall efficiency analytical equation was obtained; subsequently, by adjusting the bias and matching networks of the main and auxiliary amplifier branches, the system efficiency was improved. kStable within the safe operating range. Mathematical reconstruction can accurately quantify the voltage distribution relationship of the auxiliary amplifier when generating second harmonics and recovering the fundamental frequency, thereby simultaneously optimizing the enhancement effect of harmonic injection on the waveform shaping of the main amplifier and the additional power contribution brought by fundamental frequency recovery in the analytical model; through constraints k The safe operating range ensures that the main amplifier receives sufficient harmonic injection to improve efficiency, while preventing damage to the auxiliary amplifier due to excessive voltage stress. This method effectively overcomes the limitations of traditional designs that rely on trial and error based on experience, achieving theoretically guided optimization of the overall system efficiency. While simplifying the debugging process, it takes into account both harmonic injection effectiveness and fundamental frequency energy recovery efficiency, thus achieving a comprehensive performance improvement of high efficiency and high power output with low complexity over a wide frequency band.

[0023] This invention also provides a transmitter that integrates the aforementioned active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive into the system. The RF signal is input from the power amplifier's RF input port, amplified internally, and then directly drives the transmitting load from the output. Based on the core architecture of the power amplifier: the second harmonic generated by the auxiliary amplifier is phase-adjusted by the harmonic injection network and injected into the drain of the main amplifier, optimizing its voltage waveform to improve efficiency. Simultaneously, the fundamental wave power recovery branch extracts the fundamental wave energy that was originally wasted by the auxiliary amplifier and synthesizes it in phase with the fundamental wave of the main amplifier, both outputting to the load. This design allows the transmitter to achieve efficient termination and high-power synthesis across the entire frequency band without relying on complex passive harmonic control circuits or dual RF source drive architectures. While maintaining system simplicity and low cost, this transmitter significantly reduces parasitic losses and nonlinear distortion, greatly improving total output power and operating efficiency, making it particularly suitable for practical engineering deployments of broadband, high-efficiency, and high-power communication systems. Attached Figure Description

[0024] Figure 1 A circuit topology diagram of an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive is provided for an embodiment of the present invention. Figure 2 This is a partially enlarged schematic diagram of the harmonic separation network microstrip line structure provided in an embodiment of the present invention; Figure 3 This is a partially enlarged schematic diagram of the harmonic injection network microstrip line structure provided in an embodiment of the present invention; Figure 4 The schematic diagram of a specific implementation circuit for an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive provided in an embodiment of the present invention; Figure 5 The theoretical derivation of the overall system efficiency provided for embodiments of the present invention η sys According to voltage distribution ratio k A graph showing the changing functional relationship; Figure 6 The voltage distribution ratio provided for the embodiments of the present invention is as follows: k Comparison of theoretical and simulation results of drain voltage and current of main power amplifier at 0.6; where (a) is drain voltage; (b) is drain current; Figure 7 The voltage distribution ratio provided for the embodiments of the present invention is as follows: k Comparison of theoretical and simulation results of drain voltage and current of auxiliary power amplifier at 0.6; where (a) is drain voltage and (b) is drain current. Detailed Implementation

[0025] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] As described in the background section, existing active harmonic injection circuits still face two major technical bottlenecks in engineering applications: First, the system architecture is complex. Existing technologies either rely on dual RF source drive or frequency multipliers (which suffer from nonlinear conversion losses), greatly increasing the complexity of the transmitter. There is an urgent need for a simplified architecture with single-ended drive to improve engineering practicality. Second, there is significant waste of fundamental power. The auxiliary power amplifier is only used as a "harmonic generator" to provide the injection signal. A large amount of high-energy fundamental components generated are blocked by the filter network or dissipated in the dummy load, failing to reach the final load. This severe energy waste significantly drags down the total output power and overall efficiency of the PA system. Therefore, if this wasted energy can be effectively recovered as fundamental power and superimposed in phase with the main signal, the advantages of active harmonic injection technology can be further leveraged, thereby achieving a significant improvement in high efficiency and high power output over a wide bandwidth.

[0030] To achieve the above objectives, this embodiment provides an active harmonic injection broadband high-efficiency power amplifier based on fundamental power recovery and single-ended drive, specifically an active second harmonic injection broadband high-efficiency power amplifier based on fundamental power recovery and single-ended drive. This power amplifier effectively solves the complex problem of dual-ended drive, recovers the fundamental power of the auxiliary power amplifier, and significantly improves the overall efficiency and output power of the broadband system.

[0031] Combination Figure 1 and Figure 4 As shown, this embodiment provides an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive. The radio frequency input signal (RF Input) is divided into two equal paths by the input power divider (WPD), which drive the main amplifier branch (Main PA) and the auxiliary amplifier branch (Auxiliary PA) respectively, thus realizing complete single-ended drive.

[0032] In the main amplifier branch, the signal sequentially passes through the main amplifier input matching network (IMN), the RC stabilization network, and the DC blocking capacitor before entering the gate of the main power transistor. The drain of the main transistor is the injection point for the second harmonic. The amplified fundamental signal from the main amplifier is then sent to the Wilkinson power combiner on the output side via the main amplifier output matching network (OMN).

[0033] The drain output signal of the auxiliary amplifier transistor contains abundant fundamental and second harmonic components. This embodiment employs a harmonic separation network (HSN) to process these signals. Figure 2 As shown in the enlarged schematic diagram, the HSN in this embodiment uses a network composed of quarter-wavelength microstrip lines operating at the fundamental frequency and the second harmonic frequency, similar to a duplexer structure, to precisely separate the two signals: The first branch (second harmonic injection path): This branch consists of a quarter-wavelength series microstrip line operating at the fundamental frequency and a parallel open-circuit stub. Since this open-circuit stub is equivalent to a short circuit at the fundamental frequency, after impedance transformation by the series quarter-wavelength microstrip line, it presents extremely high impedance to the fundamental frequency at the shunt node, thus preventing the fundamental frequency from entering. The separated second harmonic is transmitted losslessly through this branch. After necessary impedance transformation and phase shift adjustment by the second harmonic matching network and the phase-shifting microstrip line, it enters the independent harmonic injection network. For example... Figure 3 As shown in the enlarged schematic diagram, HIN also consists of four intersecting microstrip lines: on the path from the drain of the main power amplifier to the fundamental matching network, a quarter-wavelength series-parallel microstrip line operating at the second harmonic frequency is used to block the leakage of the second harmonic to the fundamental load; on the upward injection path of the second harmonic, a quarter-wavelength series-parallel microstrip line operating at the fundamental frequency is used to block the fundamental frequency of the main power amplifier from flowing back into the injection branch. Ultimately, HIN achieves bidirectional physical isolation between the fundamental and harmonic frequencies while injecting the precisely phase-modulated second harmonic into the drain of the main amplifier, using this injection voltage to efficiently reconstruct the operating waveform of the main amplifier.

[0034] The second branch (fundamental power recovery path): This branch consists of a quarter-wavelength series microstrip line operating at the second harmonic frequency and a parallel open-circuit stub. Similarly, it presents high impedance to the second harmonic. The fundamental component generated by the auxiliary power amplifier is smoothly extracted through this recovery branch, and after passing through the auxiliary path's output matching network (OMN) and phase-shifted microstrip line, it is delivered to the Wilkinson power combiner on the output side.

[0035] Finally, the fundamental power output by the main amplifier and the fundamental power recovered by the auxiliary amplifier are superimposed in phase at the power combiner and output to the load together. This structure not only solves the dual-source drive problem, but also eliminates the waste of fundamental power in the auxiliary power amplifier.

[0036] As an optimized solution in this embodiment, the specific structure of this power amplifier is as follows: The circuit includes an RF input port, an input power divider, a main amplifier circuit, an auxiliary amplifier circuit, a harmonic separation network, a harmonic injection network, and an output power combiner.

[0037] The radio frequency input port is connected to the input terminal of the input power divider, which splits the radio frequency signal into two paths, which are fed into the input terminals of the main amplifier circuit and the auxiliary amplifier circuit, respectively.

[0038] The main amplifier circuit includes a main amplifier and a main amplifier output matching network. The drain of the main amplifier is connected to one end of the main amplifier output matching network, and the other end of the output matching network is connected to the first input terminal of the output power combiner.

[0039] The auxiliary amplifier circuit includes an auxiliary amplifier, the drain of which is connected to the input of the harmonic separation network.

[0040] The harmonic separation network has two output branches: the first branch is a second harmonic output branch, used to extract the second harmonic generated by the auxiliary amplifier. This branch is connected to the input terminal of the harmonic injection network, and the output terminal of the harmonic injection network is connected to the drain of the main amplifier, thereby injecting the phase-shifted second harmonic into the main amplifier; the second branch is a fundamental power recovery branch, used to extract the fundamental power generated by the auxiliary amplifier. This branch is connected to the second input terminal of the output power combiner.

[0041] The output terminals of the main amplifier circuit and the fundamental output terminals of the auxiliary amplifier circuit are both connected to the output power combiner. The two fundamental power signals are combined in phase at the output power combiner and then transmitted to the final load.

[0042] Furthermore, the main amplifier circuit also includes a main amplifier input matching network, and the auxiliary amplifier circuit also includes an auxiliary amplifier input matching network; the gate of the main amplifier is connected to the first output terminal of the input power divider through the main amplifier input matching network, and the gate of the auxiliary amplifier is connected to the second output terminal of the input power divider through the auxiliary amplifier input matching network.

[0043] Furthermore, the fundamental power recovery branch is also connected in series with an auxiliary amplifier output matching network and a phase offset microstrip line to compensate for the phase difference between the two fundamental signals, ensuring that they are superimposed in phase at the output power combiner.

[0044] Furthermore, the harmonic separation network is a microstrip line network. In a preferred embodiment, the network includes quarter-wavelength microstrip lines operating at the fundamental frequency and the second harmonic frequency, respectively, to achieve physical isolation and lossless distribution of the fundamental power and second harmonic power at the drain output of the auxiliary amplifier. For broadband applications, this network can be replaced by a broadband duplexer, a bandpass / lowpass filter bank, or a broadband directional coupler.

[0045] Furthermore, both the output power combiner and the input power divider are Wilkinson power dividers / combiners.

[0046] For example, based on the above architecture, this embodiment also provides a theoretical reconstruction and parameter optimization method, namely, a design method for an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive. This method takes the existing optimal operating state of the main amplifier as a prerequisite boundary condition, and focuses on introducing a voltage distribution ratio coefficient. k The specific steps for reconstructing the drain waveform and energy distribution model of the auxiliary amplifier are as follows: Step 1: Mathematical setting of the boundary conditions for the main amplifier: According to existing high-efficiency power amplifier theory, when the main amplifier reaches its optimal output state, its output waveform and power parameters are derived constants. In a typical embodiment of this invention, when the main amplifier is in its optimal continuous operating mode and has the highest output efficiency, its normalized drain voltage waveform theoretically satisfies the following mathematical reconstruction relationship: (1) in, v ds,M (θ) This is the drain voltage of the main amplifier.

[0047] At this time, the fundamental power output by the main amplifier to the load P 1f,M DC power consumption of the device itself P dc,M And the second harmonic injection power that it must absorb from the outside when reconstructing the optimal voltage waveform, as well as the second harmonic injection power it needs to reconstruct. P 2f,M The following formulas are given respectively: in, V dd,M This is the drain bias voltage of the main amplifier. I max,M This is the maximum drain current of the main amplifier.

[0048] The DC power consumption of the main power amplifier is shown in the following formula: (2) The fundamental output power of the main power amplifier is shown in the following formula: (3) The required harmonic injection power for the main power amplifier is shown in the following formula: (4) This invention uses the above parameters directly as prerequisite boundary conditions for subsequent power closed-loop balance calculations.

[0049] Step 2: Theoretical innovation and reconstruction of the drain waveform of the auxiliary amplifier: In order to accurately supply the above-mentioned required power to the main amplifier P 2f,M At the same time, to maximize the recoverable fundamental power of the auxiliary amplifier itself, the core of the theory of this invention lies in the innovative mathematical reconstruction of the drain waveform of the auxiliary amplifier.

[0050] To obtain a richer harmonic spectrum for harmonic injection, this embodiment biases the auxiliary power amplifier in the Class C operating region. A voltage distribution ratio factor is introduced. k (0< k<1), the time-domain equation for the drain voltage of the auxiliary power amplifier is redefined as: (5) in, v ds,A (θ) This is the drain voltage of the auxiliary amplifier. θ 1 and θ 2 represents the phase offset between the fundamental component and the second harmonic component, respectively.

[0051] Among them, the fundamental voltage amplitude With second harmonic voltage amplitude The allocation satisfies: (6) in, k This is the voltage distribution ratio coefficient. V dd,A The drain bias voltage of the auxiliary power amplifier V 1,A To assist the fundamental amplitude of the power amplifier drain voltage, V 2,A This is to assist the second harmonic amplitude of the power amplifier drain voltage.

[0052] When the auxiliary power amplifier is biased to Class C, its drain current time-domain equation can be expressed as a truncated cosine wave, as shown in the following equation: (7) Its DC component, obtained by integration, is shown in the following equation: (8) Through Fourier series expansion, its harmonic components are shown in the following equation: (9) For each harmonic, we have: (10) With a typical Class C conduction angle of 2 θ c Taking 120° as an example, its DC value can be calculated. α 0,A , fundamental wave α 1,A and second harmonic α 2,A The current Fourier coefficient constant (derived here as) α 0,A =0.218, α 1,A =0.391, α 2,A =0.276).

[0053] Therefore, the DC power consumption of the auxiliary amplifier is as follows: (11) in, P dc,A DC power consumption of the auxiliary power amplifier α 0,A The Fourier coefficients of the DC current of the auxiliary power amplifier, I max,A This is the maximum drain current of the auxiliary amplifier.

[0054] With the help of the harmonic separation network in Example 1, the fundamental power generated by the drain of the auxiliary power amplifier can be extracted and utilized (i.e., fundamental power recovery). The fundamental power generated by the drain of the auxiliary power amplifier is shown in the following formula: (12) in, P 1f,A The fundamental power extracted by the auxiliary amplifier itself, i.e., the fundamental power recovered in this patent, α 1,A The Fourier coefficients of the fundamental current of the auxiliary power amplifier.

[0055] Meanwhile, the second harmonic power injected into the main power amplifier by the auxiliary power amplifier is shown in the following formula: (13) in, P 2f,M The second harmonic power that must be absorbed from the outside to reconstruct the optimal waveform for the main amplifier is the second harmonic power that needs to be injected.

[0056] Step 3: Power balance, overall system efficiency optimization model and safe operating range verification According to the principle of energy conservation, the second harmonic power separated by the auxiliary amplifier must meet the requirements of the main amplifier, that is: (14) This equation establishes the binding relationship between the current limits of the primary and secondary transistors. In this embodiment, the auxiliary power amplifier is theoretically considered as an energy mixing generator, recovering the fundamental power. P 1f,A This weighted value is directly added to the total system output. Therefore, this invention proposes a novel overall system efficiency. η sys Define the model: (15) Substituting the power expressions derived in steps 1 and 2 (Equations 2, 3, 4, 11, 12, 13, and 14) into the overall system efficiency model (Equation 15), the overall system efficiency with respect to the voltage distribution coefficient can be obtained. kThe analytical equation.

[0057] Taking the continuous waveform injection state in this embodiment as an example, after substituting constants and simplifying, the analytical equation is as follows:

[0058] (16) like Figure 5 The figure shows the theoretically derived overall system efficiency in this embodiment. η sys According to voltage distribution ratio k The changing functional relationship curve, the overall system efficiency with k The increase is showing an upward trend.

[0059] For example, an experimental verification was conducted on the power amplifier provided in this embodiment, and the specific implementation process is as follows: Combination Figure 6 Middle (a) to Figure 7 Based on the theoretical and simulation waveforms in (b) and the specific power and efficiency data in Table 1, the following two conclusions can be drawn through comparative analysis of the above results: First, it verified the effectiveness of broadband efficient waveform reconstruction and fundamental power recovery. For example... Figure 6 (a) and Figure 6 The main amplifier waveform shown in (b) and Figure 7 (a) and Figure 7 The auxiliary amplifier waveform shown in (b) is used to verify the parameters. k When the value is 0.6, both the voltage and current waveforms closely approximate the expected optimal injection and reconfiguration states. Regarding system power and efficiency data: when... k When the efficiency is 0.6, the theoretical overall efficiency is 88.3%, and the large-signal simulation efficiency using ideal devices is 87.5%, with an output power of 1.165W in both cases. This fully demonstrates the effectiveness of the system based on... k The waveform assignment and active injection mechanism can not only achieve fine waveform shaping, but also significantly improve total power and total efficiency in practical broadband systems.

[0060] Secondly, the simulation results show extremely small relative errors compared to theoretical calculations, and the physical mechanism is reasonably explained. The simulated values ​​of system output power and total efficiency maintain a very high consistency with the theoretical values ​​(relative error less than 1%). The physical root cause of this extremely small error lies in the fact that the analytical derivation model is based on pure low-order waveform truncation (i.e., only DC, fundamental, and second harmonics are considered). However, in large-signal harmonic balance simulations, the intrinsic nonlinearity of the transistor will inevitably excite weak third and higher harmonic energy. This uncontrolled high-order harmonic energy causes slight energy leakage, resulting in the simulated total efficiency being slightly lower than the purely theoretical calculation value. This extremely small deviation is completely consistent with the actual physical laws of microwave engineering, thus proving the validity of the self-derived model of this invention. k The theoretical model and analytical equations have extremely high theoretical accuracy and are valuable for guiding practical engineering circuit design.

[0061] Furthermore, this embodiment also provides a transmitter, including the aforementioned active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive; wherein: the transmitter's RF signal output terminal is connected to the RF input port of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive, and the output terminal of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive is connected to the transmitting load for outputting the amplified RF signal. This transmitter can significantly reduce parasitic losses and nonlinear distortion, greatly improve the total output power and operating efficiency, and is particularly suitable for practical engineering deployments of broadband, high-efficiency, and high-power communication systems.

[0062] In summary, compared with existing technologies, the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive provided by this invention has the following advantages: First, this invention innovatively treats the auxiliary power amplifier as a "hybrid generator". Through a harmonic separation network, the originally wasted fundamental power is extracted and combined with the main circuit, so that this part of the power is converted into effective system output power, which greatly improves the overall efficiency and output power of the system, thereby effectively breaking through the efficiency bottleneck of traditional power amplifier design.

[0063] Secondly, this invention utilizes an input power divider to achieve single-RF port driving, completely eliminating the dependence of traditional active harmonic injection circuits on dual-RF source driving and complex external phase synchronization calibration. This not only greatly simplifies the overall system architecture but also significantly improves the engineering applicability of this technology in actual industrial scenarios such as base station transmitters.

[0064] Third, this invention employs a high-efficiency harmonic separation network at the output of the auxiliary power amplifier to achieve physical isolation between the fundamental wave and the second harmonic, ensuring the accuracy of active waveform shaping and the stability of the system under wideband operation.

[0065] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. An active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive, characterized in that, It includes an RF input port, an input power divider, a main amplifier circuit, an auxiliary amplifier circuit, a harmonic separation network, a harmonic injection network, and an output power combiner; The radio frequency input port is connected to the input terminal of the input power divider, and the output terminal of the input power divider is connected to the input terminals of the main amplifier circuit and the auxiliary amplifier circuit, respectively. The output terminal of the main amplifier circuit is connected to the first input terminal of the output power combiner. The output terminal of the auxiliary amplifier circuit is connected to the input terminal of the harmonic separation network; The harmonic separation network has two output branches: a second harmonic output branch and a fundamental power recovery branch. The second harmonic output branch is connected to the input terminal of the harmonic injection network, and the output terminal of the harmonic injection network is connected to the drain of the main amplifier in the main amplifier circuit, for injecting the phase-shifted second harmonic into the main amplifier. The fundamental power recovery branch is connected to the second input terminal of the output power combiner, for extracting the fundamental power generated by the auxiliary amplifier circuit and outputting it to the output power combiner. The output power combiner is used to combine the fundamental power output from the main amplifier circuit with the fundamental power output from the fundamental power recovery branch in phase and then output it to the load.

2. The active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive according to claim 1, characterized in that, The main amplifier circuit includes a main amplifier input matching network, a main amplifier, and a main amplifier output matching network; The gate of the main amplifier is connected to the first output terminal of the input power divider through the main amplifier input matching network, the drain of the main amplifier is connected to one end of the main amplifier output matching network, and the other end of the main amplifier output matching network is connected to the first input terminal of the output power combiner. The auxiliary amplifier circuit includes an auxiliary amplifier input matching network and an auxiliary amplifier; the gate of the auxiliary amplifier is connected to the second output terminal of the input power divider through the auxiliary amplifier input matching network, and the drain of the auxiliary amplifier is connected to the input terminal of the harmonic separation network.

3. The active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive according to claim 1, characterized in that, The fundamental power recovery branch is connected in series with an auxiliary amplifier output matching network and a phase offset microstrip line to compensate for the phase difference between the main and auxiliary fundamental signals, so that the two fundamental power signals are superimposed in phase at the output power synthesizer.

4. The active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive according to claim 1, characterized in that, The harmonic separation network adopts a microstrip line network; the microstrip line network includes quarter-wavelength microstrip lines operating at the fundamental frequency and the second harmonic frequency, respectively, to achieve physical isolation and lossless distribution of the fundamental power and second harmonic power output from the drain of the auxiliary amplifier.

5. A design method for an active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive, used to design the active harmonic injection broadband high-efficiency power amplifier based on fundamental frequency recovery and single-ended drive as described in any one of claims 1-4, characterized in that, include: Introducing voltage distribution ratio coefficient k The drain voltage waveform of the auxiliary amplifier is mathematically reconstructed. Combined with auxiliary amplifier to recover fundamental power P 1f,A , fundamental frequency output power of main amplifier P 1f,M DC power consumption of main amplifier P dc,M and auxiliary amplifier DC power consumption P dc,A Establish a voltage distribution ratio coefficient k The analytical equation for the overall system efficiency; Adjust the bias and matching networks of the main amplifier branch and the auxiliary amplifier branch to adjust the voltage distribution ratio. k Operating within a safe operating range ensures the waveform shaping effect of the main amplifier while maximizing the overall system efficiency.

6. The design method of an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive according to claim 5, characterized in that, The mathematical reconstruction of the drain voltage waveform of the auxiliary amplifier includes: When the auxiliary amplifier is biased in the Class C operating region, its drain voltage time-domain equation is defined as: in, v ds,A (θ) This is the drain voltage of the auxiliary amplifier. θ 1 and θ 2 represents the phase offset between the fundamental component and the second harmonic component, respectively; V dd,A This is the drain bias voltage for the auxiliary power amplifier; The fundamental voltage amplitude, Let be the amplitude of the second harmonic voltage, and satisfy: in, k The range of values ​​is 0 < k <1.

7. The design method of an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive according to claim 6, characterized in that, The auxiliary amplifier recovers fundamental power. P 1f,A Based on the fundamental power extracted from the auxiliary amplifier, the specific expression is as follows: in, α 1,A The Fourier coefficients of the fundamental current of the auxiliary power amplifier, I max,A This is the maximum drain current of the auxiliary amplifier; The auxiliary power amplifier is used to inject second harmonic power into the main power amplifier. P 2f,A The expression for the second harmonic power is: in, α 2,A The Fourier coefficients of the second harmonic current of the auxiliary power amplifier.

8. The design method of an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive according to claim 7, characterized in that, The specific expression of the analytical equation for the overall system efficiency is as follows: In the formula, The overall system efficiency; According to the principle of energy conservation, the second harmonic power separated by the auxiliary amplifier satisfies the injection power required for the main amplifier to reconstruct the optimal waveform. .

9. The design method of an active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive according to claim 7, characterized in that, When the main amplifier is in continuous operation mode and its output efficiency is at its highest, its various power parameters are used as prerequisite boundary conditions, specifically: The expression for the DC power consumption of the main amplifier is: ； The expression for the fundamental output power of the main amplifier is: ； The expression for the second harmonic injection power required by the main amplifier is: ； in, V dd,M This is the drain bias voltage of the main amplifier. I max,M This is the maximum drain current of the main amplifier.

10. A transmitter, characterized in that, Includes the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive as described in any one of claims 1-4; The RF signal output terminal of the transmitter is connected to the RF input port of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive. The output terminal of the active harmonic injection broadband high-efficiency power amplifier based on fundamental wave recovery and single-ended drive is connected to the transmitting load for outputting the amplified RF signal.

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