Continuous class-F power amplifier based on output end active second harmonic injection

Abstract

The invention discloses a continuous class F power amplifier based on output end active second harmonic injection, which comprises a main amplifier circuit, a harmonic injection network and an auxiliary amplification circuit, and is characterized in that the output end of the main amplifier circuit is connected with the output end of the auxiliary amplification circuit through the harmonic injection network; the auxiliary amplifier injects second harmonics into the main amplifier through the harmonic injection network; the main amplifier circuit comprises a main amplifier, and the main amplifier is a continuous F-class amplifier; the drain electrode of the main amplifier is connected with one end of the main amplifier output matching circuit, the other end of the main amplifier output matching circuit is connected with the output end load, the grid electrode of the main amplifier is connected with one end of the main amplifier input matching circuit, and the other end of the main amplifier input matching circuit is connected with the first power source.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication power amplifiers, and particularly relates to a continuous class-F power amplifier based on active second-harmonic injection at the output end. Background Art

[0002] With the rapid development of wireless communication systems, higher requirements are put forward for the performance indicators of radio frequency front-end circuits. As a core functional module in base stations and mobile terminals, the performance of radio frequency power amplifiers directly determines the energy consumption level of the entire transmitting terminal. Therefore, how to design a high-efficiency power amplifier has become a hot topic of concern for power amplifier designers. At the same time, in order to support multiple frequency bands and different communication standards, the working bandwidth of power amplifiers needs to be greatly expanded.

[0003] Currently, the research on broadband high-power power amplifiers has tended to be mature, and the proposed B / J class power amplifiers, continuous class-F power amplifiers, and continuous inverse class-F power amplifiers have attracted the most attention. The continuous class-F power amplifier is inspired by the B / J class power amplifier. By introducing voltage waveform parameters ξ to reconstruct the drain voltage waveform of the transistor, the fundamental impedance and harmonic impedance are no longer fixed values, expanding the impedance space while maintaining high-efficiency operation. In recent years, in order to further improve the efficiency and output power of power amplifiers, a method of harmonic injection has been proposed. In 2010, Abdullah et al. proposed an active harmonic injection method for traditional class-J power amplifiers at a single frequency point, achieving both high power and high efficiency of the power amplifier. In 2017, Amirreza et al. first studied the theory of second-harmonic injection at the gate node of class-J power amplifiers and found that the injection of a half-sine waveform can greatly improve the power and efficiency of class-J power amplifiers. In the same year, Amirreza et al. studied the harmonic injection at the drain node of class-J power amplifiers and proposed the class-J2 power amplifier. By injecting current to reduce the conduction angle, the drain efficiency can be increased to 83%. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of low output power and efficiency of continuous class-F power amplifiers, and a continuous class-F power amplifier based on active second-harmonic injection at the output end is proposed.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A continuous class-F power amplifier based on active second-harmonic injection at the output end includes a main amplifier circuit, a harmonic injection network, and an auxiliary amplifier circuit. The output end of the main amplifier circuit is connected to the output end of the auxiliary amplifier circuit through the harmonic injection network; the auxiliary amplifier injects second harmonics into the main amplifier through the harmonic injection network; The main amplifier circuit includes a main amplifier, which is a continuous class-F amplifier; the drain of the main amplifier is connected to one end of the main amplifier output matching circuit, the other end of the main amplifier output matching circuit is connected to the output load, the gate of the main amplifier is connected to one end of the main amplifier input matching circuit, and the other end of the main amplifier input matching circuit is connected to the first power source.

[0006] Further, one end of the harmonic injection network is connected between the drain of the main amplifier and one end of the main amplifier output matching circuit, the other end of the harmonic injection network is connected to the drain of the auxiliary amplifier, the gate of the auxiliary amplifier is connected to one end of the auxiliary amplifier input matching circuit, and the other end of the auxiliary amplifier input matching circuit is connected to the second power source.

[0007] Further, the harmonic injection network includes a band-pass filter operating in the second harmonic frequency band.

[0008] A design method of a continuous class-F power amplifier based on active second harmonic injection at the output end, using the continuous class-F power amplifier based on active second harmonic injection at the output end described above, includes the following steps: According to the drain voltage normalization formula of the main amplifier introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, and the drain current normalization formula of the main amplifier introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, calculate the output power and drain efficiency of the continuous class-F power amplifier with active second harmonic injection at the output end.

[0009] Further, the drain voltage normalization formula of the main amplifier introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier is as follows:

[0010] Wherein, v ds (θ) is the drain voltage of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ is a parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; The drain current normalization formula of the continuous class-F amplifier introducing the optimal phase shift parameter between the drain voltage and drain current of the continuous class-F amplifier is as follows:

[0011] Among them, i ds (θ) is the drain current of the continuous class-F amplifier.

[0012] Furthermore, the output power and drain efficiency of the main amplifier are as follows:

[0013]

[0014] Among them, P out, f is the output power of the main amplifier, η is the drain efficiency of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter that constitutes the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; α 0 represents ; When α+α 0 = π / 2, the maximum drain efficiency of the main amplifier is as follows:

[0015] Among them, η max is the maximum drain efficiency of the main amplifier; When ξ ≠0, the maximum drain efficiency of the main amplifier η max is greater than the efficiency 90.7% of the traditional continuous class-F power amplifier; When ξ takes values in the range from -1 to -0.536 or 0.536 to 1, the maximum drain efficiency of the main amplifier η max is greater than 100%.

[0016] Furthermore, the second harmonic power provided by the auxiliary amplifier is as follows:

[0017] Among them, P out,2fThe second - harmonic power provided to the auxiliary amplifier; v 1 = , v 3 = / 9, α is the optimal phase - shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter that constitutes the drain - voltage waveform of the main amplifier, and its value range is from - 1 to 1; The DC power loss of the overall circuit structure of the continuous class - F power amplifier with active second - harmonic injection at the output terminal is shown as follows:

[0018] where, P DC_total is the DC power loss of the overall circuit structure of the continuous class - F power amplifier with active second - harmonic injection at the output terminal, P DC_main is the DC power loss of the main amplifier, η 2 is the drain efficiency of the auxiliary amplifier; P out,2f is the second - harmonic power provided to the auxiliary amplifier.

[0019] Furthermore, the total output power and the overall drain efficiency of the continuous class - F power amplifier with active second - harmonic injection at the output terminal are shown as follows:

[0020]

[0021] where, P out_total is the total output power of the continuous class - F power amplifier with active second - harmonic injection at the output terminal, η total is the overall drain efficiency of the continuous class - F power amplifier with active second - harmonic injection at the output terminal; v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase - shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter that constitutes the drain - voltage waveform of the main amplifier, and its value range is from - 1 to 1, η 2 is the drain efficiency of the auxiliary amplifier; When ξWhen ≠ 0, the total output power of the continuous class-F power amplifier with active second-harmonic injection at the output P out_total is greater than the output power of the traditional continuous class-F power amplifier; When ξ is -1 or 1, the total output power of the continuous class-F power amplifier with active second-harmonic injection at the output P out_total has a maximum value that is 1.323 times the output power of the traditional continuous class-F power amplifier; When η 2 is 100%, η total the overall drain efficiency of the continuous class-F power amplifier with active second-harmonic injection at the output is the theoretical maximum value of 98.16%.

[0022] Furthermore, the fundamental impedance and second-harmonic impedance of the main amplifier are as shown in the following formula:

[0023]

[0024] Among them, Z f0 is the fundamental impedance of the main amplifier, Z 2f0 is the second-harmonic impedance, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase-shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter that constitutes the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; When ξ ≠ 0, the real part of the second-harmonic impedance Z 2f0 is negative, and at this time the second harmonic is a power-generating component.

[0025] A transmitter includes the continuous class-F power amplifier based on active second-harmonic injection at the output described above.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects: The continuous class-F power amplifier based on active second-harmonic injection at the output proposed by the present invention injects a second-harmonic component into the drain node of the traditional continuous class-F power amplifier through an auxiliary power amplifier, changing the drain voltage vds (θ) and the drain current i ds (θ) The phase shift between them is used to improve the output power and efficiency of the continuous class-F power amplifier.

[0027] The present invention can select appropriate optimal phase shift parameters ξ for different parameters in the drain voltage formula of the continuous class-F power amplifier α and an auxiliary power amplifier operating at the second harmonic frequency of the required frequency band to improve the output power and efficiency of the continuous class-F power amplifier. At the same time, this design meets the requirements of the power amplifier for broadband operation, expanding the application scenarios and prospects of the continuous class-F power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments and descriptions thereof are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0029] Figure 1 FIG. is a schematic circuit diagram of a continuous class-F power amplifier based on active second harmonic injection at the output end according to the present invention.

[0030] Figure 2 FIG. is the overall drain efficiency of a continuous class-F power amplifier based on active second harmonic injection at the output end according to the present invention η total As the drain efficiency of the auxiliary power amplifier η 2 and the parameters of the continuous class-F drain voltage waveform ξ (-1 ≤ ξ ≤ 1) vary.

[0031] Figure 3 FIG. is the drain voltage ξ of a continuous class-F power amplifier based on active second harmonic injection at the output end when the parameters of the continuous class-F drain voltage waveform v ds (θ) vary from -1 to 1 with a step size of 0.5, and the theoretical waveforms of the drain current i ds (θ) and the theoretical waveform.

[0032] Figure 4a FIG. is a schematic ADS simulation diagram of a traditional continuous class-F power amplifier without harmonic injection; Figure 4b FIG. is a schematic ADS simulation diagram of a continuous class-F power amplifier based on active second harmonic injection at the output end according to the present invention; Figure 5aFor the parameters of the continuous class-F drain voltage waveform ξ When it is 1, the drain voltage of the continuous class-F power amplifier based on active second-harmonic injection at the output v ds (θ) Simulation waveforms and drain current i ds (θ) Simulation waveforms; Figure 5b When the parameters of the continuous class-F drain voltage waveform ξ are -1, the drain voltage of the continuous class-F power amplifier based on active second-harmonic injection at the output v ds (θ) Simulation waveforms and drain current i ds (θ) Simulation waveforms. Specific implementation manners

[0033] In order to enable those skilled in the art of the present technology to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] Embodiment 1 Refer to Figure 1 , a continuous class-F power amplifier based on active second-harmonic injection at the output, including a main amplifier circuit, a harmonic injection network, and an auxiliary amplifier circuit. The output end of the main amplifier circuit is connected to the output end of the auxiliary amplifier circuit through the harmonic injection network; the auxiliary amplifier injects second harmonics into the main amplifier through the harmonic injection network; The main amplifier circuit includes a main amplifier, which is a continuous class-F amplifier; the drain of the main amplifier is connected to one end of the main amplifier output matching circuit, the other end of the main amplifier output matching circuit is connected to the output load, the gate of the main amplifier is connected to one end of the main amplifier input matching circuit, and the other end of the main amplifier input matching circuit is connected to the first power source.

[0036] Preferably, one end of the harmonic injection network is connected between the drain of the main amplifier and one end of the main amplifier output matching circuit, the other end of the harmonic injection network is connected to the drain of the auxiliary amplifier, the gate of the auxiliary amplifier is connected to one end of the auxiliary amplifier input matching circuit, and the other end of the auxiliary amplifier input matching circuit is connected to the second power source. The power source generates the power required by the auxiliary amplifier.

[0037] Preferably, the harmonic injection network includes a band-pass filter operating in the second harmonic frequency band.

[0038] A design method of a continuous class-F power amplifier based on active second harmonic injection at the output end, using the continuous class-F power amplifier based on active second harmonic injection at the output end described above, includes the following steps: According to the main amplifier drain voltage normalization formula introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, and the main amplifier drain current normalization formula introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, calculate the output power and drain efficiency of the continuous class-F power amplifier with active second harmonic injection at the output end.

[0039] Preferably, the main amplifier drain voltage normalization formula introducing the optimal phase shift parameter between the drain voltage and drain current of the main amplifier is as follows:

[0040] Wherein, v ds (θ) is the drain voltage of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; The continuous class-F amplifier drain current normalization formula introducing the optimal phase shift parameter between the drain voltage and drain current of the continuous class-F amplifier is as follows:

[0041] Among them, i ds (θ) is the drain current of the continuous class-F amplifier.

[0042] Preferably, the output power and drain efficiency of the main amplifier are as follows:

[0043]

[0044] Among them, P out, f is the output power of the main amplifier, η is the drain efficiency of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter that constitutes the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; α 0 means ; When α+α 0 = π / 2, the maximum drain efficiency of the main amplifier is as follows:

[0045] Among them, η max is the maximum drain efficiency of the main amplifier; When ξ ≠0, the maximum drain efficiency of the main amplifier η max is greater than the efficiency 90.7% of the traditional continuous class-F power amplifier; When ξ takes values in the range from -1 to -0.536 or 0.536 to 1, the maximum drain efficiency of the main amplifier η max is greater than 100%.

[0046] Preferably, the second harmonic power provided by the auxiliary amplifier is as follows:

[0047] Among them, Pout,2f The second - harmonic power provided for the auxiliary amplifier; v 1 = , v 3 = / 9, α is the optimal phase - shift parameter between the drain voltage and the drain current of the main amplifier, ξ is a parameter that constitutes the drain - voltage waveform of the main amplifier, and its value range is from - 1 to 1; The DC power loss of the overall circuit structure of a continuous class - F power amplifier with active second - harmonic injection at the output end is shown as follows:

[0048] where, P DC_total is the DC power loss of the overall circuit structure of a continuous class - F power amplifier with active second - harmonic injection at the output end, P DC_main is the DC power loss of the main amplifier, η 2 is the drain efficiency of the auxiliary amplifier; P out,2f is the second - harmonic power provided for the auxiliary amplifier.

[0049] Preferably, the total output power and the overall drain efficiency of a continuous class - F power amplifier with active second - harmonic injection at the output end are shown as follows:

[0050]

[0051] where, P out_total is the total output power of a continuous class - F power amplifier with active second - harmonic injection at the output end, η total is the overall drain efficiency of a continuous class - F power amplifier with active second - harmonic injection at the output end; v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase - shift parameter between the drain voltage and the drain current of the main amplifier, ξ is a parameter that constitutes the drain - voltage waveform of the main amplifier, and its value range is from - 1 to 1, η 2 is the drain efficiency of the auxiliary amplifier; When ξWhen ≠ 0, the total output power of a continuous class - F power amplifier with active second - harmonic injection at the output P out_total is greater than the output power of a traditional continuous class - F power amplifier; When ξ is - 1 or 1, the total output power of a continuous class - F power amplifier with active second - harmonic injection at the output P out_total has a maximum value that is 1.323 times the output power of a traditional continuous class - F power amplifier; When η 2 is 100%, η total the overall drain efficiency of a continuous class - F power amplifier with active second - harmonic injection at the output is 98.16%, which is the theoretical maximum value.

[0052] Preferably, the fundamental - wave impedance and the second - harmonic impedance of the main amplifier are as shown in the following formula:

[0053]

[0054] Among them, Z f0 is the fundamental - wave impedance of the main amplifier, Z 2f0 is the second - harmonic impedance, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase - shift parameter between the drain voltage and the drain current of the main amplifier, ξ is a parameter that constitutes the drain - voltage waveform of the main amplifier, and its value range is from - 1 to 1; When ξ ≠0, the real part of the second - harmonic impedance Z 2f0 is negative, and at this time, the second - harmonic is a power - generating component.

[0055] A transmitter includes the continuous class - F power amplifier based on active second - harmonic injection at the output described above.

[0056] Example 2 A design method of a continuous class - F power amplifier based on active second - harmonic injection at the output, including: introducing the optimal phase - shift parameter between the drain voltage and the drain current of the continuous class - F main power amplifier α, the drain efficiency is calculated according to this parameter and the normalized drain voltage and drain current formulas. According to the above, there is an unreasonable phenomenon that the maximum drain efficiency is greater than 100%, indicating that the second harmonic is no longer a power-consuming component but a power-generating component at this time. Therefore, an auxiliary amplifier for providing the second harmonic component to the main amplifier is introduced. The output end of the auxiliary amplifier is connected to the output end of the main amplifier through a harmonic injection network, and the overall drain efficiency of the power amplifier with active second harmonic injection is calculated according to the above relationship.

[0057] The novel broadband high-efficiency continuous class-F power amplifier efficiency improvement theory and design method based on active second harmonic injection at the output end include the following steps: Introduce the optimal phase shift parameter between the drain voltage and drain current of the continuous class-F main power amplifier α , and calculate the drain efficiency according to this parameter and the normalized drain voltage and drain current formulas η , specifically, introduce the optimal phase shift parameter α , the drain voltage of the continuous class-F power amplifier v ds (θ) The normalization formula is shown as follows: (1) Where v DC = 1, v 1 = , v 3 = / 9, ξ is a parameter constituting the continuous class-F drain voltage waveform, and its value range is from -1 to 1; The drain current of the continuous class-F power amplifier i ds (θ) The normalization formula is shown as follows: (2) v ds (θ) and i ds (θ) The waveform is shown in Figure 3 ; According to Equation (1) and Equation (2), the output power P out, f and the drain efficiency η are shown as follows: (3) (4) Whereα 0 can be expressed as: (5) Furthermore, according to Equation (4), it can be calculated that when α+α 0 = is π / 2, the maximum drain efficiency η max is shown as follows: (6) According to Equation (6), it can be found that except for the case where ξ is 0, the maximum drain efficiency η max can all be improved to be greater than the efficiency (90.7%) of the traditional class-F continuous power amplifier by selecting appropriate optimal phase shift parameters α . However, when ξ takes values in the range from -1 to -0.536 or from 0.536 to 1, the maximum drain efficiency η max will be greater than 100%. For example, when ξ takes the value of -1 or 1, the maximum drain efficiency η max is 120%. This obviously unreasonable phenomenon is because after introducing the optimal phase shift parameter α , the second harmonic of the class-F continuous power amplifier is no longer a power-consuming component but a power-generating component.

[0058] Furthermore, an auxiliary amplifier is introduced to provide the second harmonic component to the main amplifier. The output end of the auxiliary amplifier is connected to the output end of the main amplifier through a harmonic injection network. According to the above relationship, the overall drain efficiency of the power amplifier with active second harmonic injection is calculated η total . In order to achieve the theoretical derivation after introducing the optimal phase shift parameter α , an auxiliary amplifier operating in the second harmonic frequency band needs to be added. The output end of the auxiliary amplifier provides the second harmonic component to the output end of the main amplifier through the harmonic injection network. The harmonic injection network is a band-pass filter operating in the second harmonic frequency band, aiming to inject the second harmonic component into the main amplifier without loss and prevent the fundamental power of the main amplifier from leaking to the auxiliary amplifier.

[0059] According to Equation (1) and Equation (2), the minimum second harmonic power that the auxiliary amplifier needs to provide can be calculated P out,2f as shown in the following equation: (7) At the same time, for the circuit structure after adding the harmonic injection of the auxiliary amplifier, the overall DC power loss P DC_totalAs shown in the following formula: (8) Wherein, P DC_main is the DC power loss of the main amplifier, η 2 is the drain efficiency of the auxiliary amplifier; According to Equations (3), (5), (7) and (8), the total output power of the power amplifier with active second-harmonic injection can be calculated P out_total and the overall drain efficiency η total as shown in the following formula: (9) (10) According to Equation (9), it can be found that except for the case where ξ is 0, the total output power P out_total is greater than the output power of the traditional continuous class-F power amplifier. Especially when ξ is -1 or 1, the maximum value of the total output power P out_total is 1.323 times that of the output power of the traditional continuous class-F power amplifier.

[0060] According to Equation (10), it can be found that the overall drain efficiency η total increases with the increase of the drain efficiency η 2 of the auxiliary amplifier. Especially when η 2 is 100%, the theoretical maximum drain efficiency can reach 98.16%. The waveform of the overall drain efficiency η total is shown in Figure 2 .

[0061] Furthermore, according to Equations (1), (2) and (5), the fundamental impedance Z f0 and the second-harmonic impedance Z 2f0 of the main amplifier can be calculated as shown in the following formula: (11) (12) According to Equations (11) and (12), it can be found that different from the traditional continuous class-F power amplifier, the fundamental impedance Z f0 of the main amplifier has no imaginary part, and except for the case where ξ is 0, the second-harmonic impedance Z 2f0The real parts are all negative values, confirming that the second harmonic is a power-producing component rather than a power-consuming component at this time. At the same time, as ξ varies from -1 to 1, different fundamental wave impedances and second harmonic impedances of the main amplifier can be obtained, indicating that a broad impedance space is provided, meeting the requirements of broadband power amplifiers.

[0062] The ADS simulation schematic diagram of the traditional class-F continuous power amplifier without harmonic injection is used to verify the theoretical analysis, as shown in Figure 4a . The specific ADS simulation settings in this embodiment are as shown in Figure 4b . The harmonic injection network uses a multiplexer composed of 4 λ / 4 ( λ is the wavelength) transmission lines, acting as a band-pass filter, allowing the fundamental wave signal to fully flow into the load and injecting the required second harmonic components into the main amplifier. To simplify the simulation, the Figure 1 auxiliary amplifier shown is replaced with a radio frequency signal source operating at the second harmonic frequency. The characteristics of the transistor used are also as shown in Figure 4b . The drain voltage is 5V, the gate voltage is 0V, the knee point voltage is 0V, and the maximum drain current is 0.5A. When the parameters ξ of the class-F continuous drain voltage waveform are 1 and -1 respectively at this time, the ideal fundamental wave impedance and harmonic impedance of the novel broadband and high-efficiency class-F power amplifier based on active second harmonic injection at the output end are shown in Table 1.

[0063] Table 1 Fundamental wave impedance and harmonic impedance when the parameters ξ of the class-F continuous drain voltage waveform are 1 and -1

[0064] According to Table 1, the load fundamental wave impedance and harmonic impedance are set to the ideal values, and simulation is carried out using lossless ideal passive components.

[0065] Based on the above design idea, when the parameters ξ of the class-F continuous drain voltage waveform are 1 or -1, the drain voltage v ds (θ) simulation waveform and drain current i ds (θ) simulation waveforms of the novel broadband and high-efficiency class-F power amplifier based on active second harmonic injection at the output end are as shown in Figure 5a and Figure 5b . The theoretical calculations and simulated drain efficiencies and output powers of the traditional class-F power amplifier without harmonic injection and the class-F power amplifier with active second harmonic injection at the output end are shown in Table 2.

[0066] Table 2 Theoretical and simulated drain efficiency and output power of traditional continuous class-F and after second-harmonic injection

[0067] From the comparison between the above simulation results and theoretical calculation results, the following conclusions can be drawn: 1. Compared with the performance of traditional continuous class-F power amplifiers, when the active second-harmonic injection is applied at the output end, when the parameter of the drain voltage waveform ξ is 1, the output power and drain efficiency increase by 33.1% and 9.7% respectively; when the parameter of the drain voltage waveform ξ is -1, the output power and drain efficiency increase by 31.3% and 9.4% respectively. Therefore, it can be proved that the method of active second-harmonic injection at the output end does improve the overall performance of continuous class-F power amplifiers, and further expands the application scenarios and prospects of continuous class-F high-efficiency power amplifiers.

[0068] 2. The relative errors between the simulation results and theoretical calculation results of the output power and drain efficiency are very small. When the parameter of the drain voltage waveform ξ is 1, the relative errors between the simulation results and theoretical calculation results of the output power and drain efficiency during second-harmonic injection are only 0.63% and 0.66% respectively; when the parameter of the drain voltage waveform ξ is -1, the relative errors between the simulation results and theoretical calculation results of the output power and drain efficiency during second-harmonic injection are only 1.99% and 0.96% respectively. Therefore, the correctness of the design method of the continuous class-F power amplifier based on active second-harmonic injection at the output end can be verified.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: after reading the present invention, various changes, modifications or equivalent replacements can still be made to the specific implementation manners of the invention, but these changes, modifications or equivalent replacements are all within the scope of the protection of the pending claims of the invention.

Claims

1. A continuous class F power amplifier based on active second harmonic injection at the output, characterized in that: It includes a main amplifier circuit, a harmonic injection network and an auxiliary amplifier circuit, wherein the output end of the main amplifier circuit is connected to the output end of the auxiliary amplifier circuit through the harmonic injection network; the auxiliary amplifier injects the second harmonic into the main amplifier through the harmonic injection network; The main amplifier circuit includes a main amplifier, which is a continuous class F amplifier; the drain of the main amplifier is connected to one end of the main amplifier output matching circuit, the other end of the main amplifier output matching circuit is connected to the output load, the gate of the main amplifier is connected to one end of the main amplifier input matching circuit, and the other end of the main amplifier input matching circuit is connected to the first power source.

2. The continuous class F power amplifier based on active second harmonic injection at the output end according to claim 1, characterized in that: One end of the harmonic injection network is connected between the drain of the main amplifier and one end of the main amplifier output matching circuit, the other end of the harmonic injection network is connected to the drain of the auxiliary amplifier, the gate of the auxiliary amplifier is connected to one end of the auxiliary amplifier input matching circuit, and the other end of the auxiliary amplifier input matching circuit is connected to the second power source.

3. The continuous class F power amplifier based on active second harmonic injection at the output end according to claim 1, characterized in that: The harmonic injection network includes a bandpass filter operating in the second harmonic frequency band.

4. A design method for a continuous class F power amplifier based on active second harmonic injection at the output end, using the continuous class F power amplifier based on active second harmonic injection at the output end as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: calculating the output power and drain efficiency of a continuous class F power amplifier with active second harmonic injection at the output end according to a drain voltage normalization formula of a main amplifier which introduces an optimal phase shift parameter between the drain voltage and the drain current of the main amplifier, and a drain current normalization formula of a main amplifier which introduces an optimal phase shift parameter between the drain voltage and the drain current of the main amplifier.

5. The design method of a continuous class F power amplifier based on active second harmonic injection at the output end according to claim 4, characterized in that: The drain voltage normalization formula of the main amplifier, which introduces the optimal phase shift parameter between the drain voltage and the drain current of the main amplifier, is as follows: in, v ds (θ) is the drain voltage of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ It is the parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; The drain current normalization formula of the main amplifier which introduces the optimal phase shift parameter between the drain voltage and the drain current of the main amplifier is as follows: in, i ds (θ) is the drain current of the main amplifier.

6. The design method of a continuous class F power amplifier based on active second harmonic injection at the output end according to claim 5, characterized in that: The output power and drain efficiency of the main amplifier are given by: in, P out, f is the output power of the main amplifier, η is the drain efficiency of the main amplifier, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ It is the parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; α 0 is represented by ; when α+α 0 = When π / 2, the maximum drain efficiency of the main amplifier is as follows: in, η max is the maximum drain efficiency of the main amplifier; when ξ ≠0, the maximum drain efficiency of the main amplifier η max Greater than the efficiency of traditional continuous Class F amplifiers, which is 90.7%; when ξ The maximum drain efficiency of the main amplifier is in the range of -1 to -0.536 or 0.536 to 1. η max Greater than 100%.

7. The design method of a continuous class F power amplifier based on active second harmonic injection at the output end according to claim 5, characterized in that: The second harmonic power provided by the auxiliary amplifier is shown in the following equation: in, P out,2f Second harmonic power provided to auxiliary amplifier; v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ It is the parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; The overall DC power loss of the circuit structure of a continuous class F power amplifier with active second harmonic injection at the output is shown as follows: in, P DC_total The overall DC power loss of the circuit structure of a continuous class F power amplifier with active second harmonic injection at the output, P DC_main is the DC power loss of the main amplifier, η 2 is the drain efficiency of the auxiliary amplifier; P out,2f Second harmonic power provided to auxiliary amplifier.

8. The design method of a continuous class F power amplifier based on active second harmonic injection at the output end according to claim 5, characterized in that: The total output power and overall drain efficiency of a continuous class F power amplifier with active second harmonic injection at the output are given by: in, P out_total is the total output power of a continuous class F power amplifier with active second harmonic injection at the output, η total Overall drain efficiency of a continuous class F power amplifier with active second harmonic injection at the output; v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ is the parameter of the drain voltage waveform of the main amplifier, and its value range is -1 to 1. η 2 is the drain efficiency of the auxiliary amplifier; when ξ ≠0, the total output power of the continuous class F power amplifier with active second harmonic injection at the output P out_total Greater than the output power of traditional continuous Class F amplifiers; when ξ The total output power of a continuous class F power amplifier with active second harmonic injection at the output is -1 or 1. P out_total The maximum value is 1.323 times the output power of the traditional continuous Class F amplifier; when η When 2 is 100%, η total The overall drain efficiency of the continuous class F power amplifier with active second harmonic injection at the output is 98.16% of the theoretical maximum value.

9. The design method of a continuous class F power amplifier based on active second harmonic injection at the output end according to claim 5, characterized in that: The fundamental impedance and second harmonic impedance of the main amplifier are shown as follows: in, Z f0 is the fundamental impedance of the main amplifier, Z 2f0 is the second harmonic impedance, v DC = 1, v 1 = , v 3 = / 9, α is the optimal phase shift parameter between the drain voltage and drain current of the main amplifier, ξ It is the parameter constituting the drain voltage waveform of the main amplifier, and its value range is from -1 to 1; when ξ ≠0, the second harmonic impedance Z 2f0 The real part of is negative, and the second harmonic is a production component.

10. A transmitter, characterized in that: The invention comprises a continuous class F power amplifier based on active second harmonic injection at the output end as described in any one of claims 1 to 3.

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