Matching structure and power amplifier

Abstract

The invention relates to a matching structure and a power amplifier, and is applied to the technical field of electronic devices, the matching structure is applied to the power amplifier, the power amplifier comprises a power amplifier tube, and the matching structure comprises a first fundamental wave matching network, a second fundamental wave matching network and a dispersion compensation network; the first fundamental wave matching network is connected with the input end of the power amplifier tube; the second fundamental wave matching network is connected with the output end of the power amplifier tube; and the dispersion compensation network is connected with the second fundamental wave matching network and is used for compensating linear frequency dispersion in the power amplifier. The problem that in the prior art, internal parasitic parameters and a matching structure of a power amplifier tube in a power amplifier can cause frequency dispersion, and consequently impedance and phase dispersion of the power amplifier are not beneficial to broadband is solved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic devices, and in particular to a matching structure and a power amplifier. Background Art

[0002] In order to meet the growing demand for high data rates, high spectrum utilization and large capacity, modern communication systems are increasingly adopting complex and high-order modulation methods. Especially in the 5G era, with the widespread application of Massive MIMO technology, people have experienced the ultimate experience brought by high speed, large connection and large capacity. 5G uses higher-order orthogonal amplitude modulation (64 / 256QAM) and multi-carrier aggregation (CA). These advanced solutions will introduce a series of problems such as higher peak-to-average ratio (PAPR) and larger bandwidth modulated signals and smaller error vector magnitude (EVM) standards. Among them, higher signal peak-to-average ratio means that the system link needs to have high linearity within a larger power back-off range, larger signal bandwidth requires broadbandization of 5G MassiveMIMO systems, and smaller error vector magnitude standards bring greater challenges to system linearity.

[0003] The power amplifier is the most energy-consuming and most nonlinear module in the RF system. It is usually located at the RF front end, and its performance directly affects the system performance.

[0004] In the related art, the internal parasitic parameters and matching structure of the power amplifier tube in the power amplifier will cause frequency dispersion, resulting in impedance and phase dispersion of the power amplifier, which is not conducive to broadbandization. Summary of the invention

[0005] The present application provides a matching structure and a power amplifier to solve the problem in the prior art that the internal parasitic parameters and matching structure of the power amplifier tube in the power amplifier may cause frequency dispersion, resulting in impedance and phase dispersion of the power amplifier, which is not conducive to broadbandization.

[0006] In a first aspect, an embodiment of the present application provides a matching structure, which is applied to a power amplifier, wherein the power amplifier includes a power amplifier tube, and the matching structure includes: a first fundamental wave matching network, a second fundamental wave matching network, and a dispersion compensation network;

[0007] The first fundamental wave matching network is connected to the input end of the power amplifier tube;

[0008] The second fundamental wave matching network is connected to the output end of the power amplifier tube;

[0009] The dispersion compensation network is connected to the second fundamental wave matching network and is used to compensate for the linear frequency dispersion in the power amplifier.

[0010] In a second aspect, an embodiment of the present application provides a power amplifier, characterized in that it includes: the matching structure and power amplifier tube described in the first aspect.

[0011] The above technical solution provided by the embodiment of the present application has the following advantages over the prior art: the matching structure provided by the embodiment of the present application is applied to a power amplifier through a matching structure, the power amplifier includes a power amplifier tube, and the matching structure includes: a first fundamental matching network, a second fundamental matching network and a dispersion compensation network; the first fundamental matching network is connected to the input end of the power amplifier tube; the second fundamental matching network is connected to the output end of the power amplifier tube; the dispersion compensation network is connected to the second fundamental matching network, and is used to compensate for the linear frequency dispersion in the power amplifier. In this way, by setting a dispersion compensation network, the linear frequency dispersion in the power amplifier can be compensated, so that the output phase of the power amplifier is flatter within the working frequency band, and the output impedance is more concentrated, thereby improving the matching friendliness of the output end of the power amplifier and realizing the bandwidth expansion of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0014] Figure 1 A schematic diagram of a matching structure provided in one embodiment of the present application;

[0015] Figure 2 It is a structural diagram of the dispersion compensation network principle;

[0016] Figure 3 (a) is a schematic diagram of the dispersion compensation effect of phase dispersion;

[0017] Figure 3 (b) is a schematic diagram of the dispersion compensation effect of impedance dispersion;

[0018] Figure 4 (a) is a schematic diagram of a structure of a dispersion compensation network implementation;

[0019] Figure 4 (b) is a schematic diagram of the structure of another implementation of the dispersion compensation network;

[0020] Figure 4(c) is a schematic diagram of the structure of another implementation of the dispersion compensation network;

[0021] Figure 4 (d) is a schematic diagram of the structure of another implementation of the dispersion compensation network;

[0022] Figure 4 (e) is a schematic diagram of the structure of another implementation of the dispersion compensation network;

[0023] Figure 5 A schematic diagram of a matching structure provided in another embodiment of the present application;

[0024] Figure 6 Circuit diagram of input parasitic capacitance and output parasitic capacitance of power amplifier tube

[0025] Figure 7 (a) is a schematic diagram of a structure of a notch network implementation;

[0026] Figure 7 (b) is a schematic diagram of another implementation of a notch network;

[0027] Figure 7 (c) is a schematic diagram of another implementation of a notch network;

[0028] Figure 7 (d) is a schematic diagram of another implementation of a notch network;

[0029] Figure 8 It is a schematic diagram of the notch network transfer function;

[0030] Fig. 9 A schematic diagram of a specific implementation of a matching structure provided in an embodiment of the present application;

[0031] Fig.10 A structural diagram of a specific implementation method of a matching structure provided in another embodiment of the present application.

[0032] Power amplifier tube-1, first fundamental wave matching network-2, second fundamental wave matching network-3, dispersion compensation network-4, first notch network-5, second notch network-6. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] According to an embodiment of the present application, a matching structure is provided, which is applied to a power amplifier, wherein the power amplifier includes a power amplifier tube 1, see Figure 1 , the matching structure includes:

[0035] The matching structure includes: a first fundamental wave matching network 2, a second fundamental wave matching network 3 and a dispersion compensation network 4;

[0036] The first fundamental wave matching network is connected to the input end of the power amplifier tube;

[0037] The second fundamental wave matching network is connected to the output end of the power amplifier tube;

[0038] The dispersion compensation network is connected to the second fundamental wave matching network and is used to compensate for the linear frequency dispersion in the power amplifier.

[0039] The first fundamental wave matching network and the second fundamental wave matching network have the same function, both of which are used to perform fundamental wave matching on the signal in the power amplifier. The specific structure thereof can be found in the related art and will not be described in detail here.

[0040] By setting up a dispersion compensation network, the network has a left-hand transmission characteristic of nonlinear dispersion, and its phase constant is inversely proportional to the frequency. Therefore, it can be used to compensate for the linear frequency dispersion caused by the parasitic capacitance of the pre-stage network and the power amplifier tube itself, making the output phase of the power amplifier flatter within the operating frequency band and the output impedance more concentrated, thereby improving the matching friendliness of the power amplifier output end and realizing the bandwidth expansion of the power amplifier.

[0041] The preceding network refers to a network connected before the input end of the dispersion compensation network. For example, the preceding network may include a second fundamental wave matching network.

[0042] In an optional embodiment, the dispersion compensation network adjusts the phase at both ends of the dispersion compensation network by changing its own network parameters so that the target phase produces a frequency offset in the opposite direction to the phase of the preceding network, and the preceding network includes the second fundamental matching network.

[0043] In some embodiments, Figure 2 For a schematic diagram of the dispersion compensation network principle, see Figure 2 By changing its network parameters, the phase Phase32 between the two ports Port3 and Port2 of the network can be controlled to produce a frequency shift in the opposite direction of the phase Phase21 between the previous network (including the second fundamental matching network and the second notch network) and the output parasitic capacitor, thereby achieving the effect of compensating for the dispersion.

[0044] Figure 3Schematic diagram of dispersion compensation effect in two cases: phase dispersion and impedance dispersion. Figure 3 It can be determined that the dispersion compensation effect is achieved by setting up a dispersion compensation network.

[0045] In an optional embodiment, the dispersion compensation network includes a combination of one or more of a lumped element, a microstrip structure with interdigital capacitors and a stub.

[0046] The specific implementation of the dispersion compensation network can be found in Figure 4 , including but not limited to implementation with lumped elements, implementation with microstrip structures with interdigital capacitors and short stubs, or a combination of the above implementation methods. Among them, the three lumped element implementation methods all achieve left-handed transmission characteristics with nonlinear frequency dispersion by setting appropriate capacitance and inductance values. The microstrip structure implementation method is essentially an LC circuit, which achieves left-handed transmission characteristics by changing its microstrip size to have specific inductance and capacitance values.

[0047] in, Figure 4 (a) Figure 4 (b) and Figure 4 (c) are all lumped element implementations. Figure 4 (d) and Figure 4 (e) are all implementation methods of microstrip structure.

[0048] In an alternative embodiment, see Figure 5 , the network structure also includes: a first notch network 5 and a second notch network 6;

[0049] The first notch network is connected to the input end of the power amplifier tube;

[0050] The second notch network is connected to the second fundamental wave matching network and the dispersion compensation network;

[0051] The first notch network is used to perform notch processing on the nonlinear component generated by the input parasitic capacitance of the power amplifier tube, and the second notch network is used to perform notch processing on the nonlinear component generated by the output parasitic capacitance of the power amplifier tube.

[0052] In some embodiments, by setting a notch network (i.e., a first notch network and a second notch network) at both the input and output ends of the power amplifier tube, the network can perform notch processing on the nonlinear components generated by the input and output parasitic capacitances of the power amplifier tube by short-circuiting the second harmonic, thereby making the power amplifier exhibit high notch characteristics at the second harmonic and improving the linearity of the power amplifier.

[0053] See also Figure 6 , Figure 6 This is a circuit diagram of the input parasitic capacitance and output parasitic capacitance of the power amplifier tube.

[0054] In an optional embodiment, the first notch network and the second notch network include a combination of one or more of a lumped element, a microstrip stub, a defective ground structure, and a defective microstrip structure.

[0055] The specific implementation of the notch network can be found in Figure 7 , including but not limited to implementation by lumped elements, implementation by microstrip stubs, implementation by defective ground structures, implementation by defective microstrip structures and similar related combinations. Among them, Figure 7 (a) is the implementation method of lumped elements, Figure 7 (b) is the implementation method of open circuit stub, Figure 7 (c) is the implementation method of the defective ground structure, Figure 7 (d) is the implementation method of the defective microstrip structure.

[0056] Among them, the lumped element adopts LC series resonance. When the inductance and capacitance values ​​meet (where L1 represents the inductance value in the lumped element, C1 represents the capacitance value in the lumped element, and F0 represents the operating frequency of the power amplifier tube), the second harmonic can be short-circuited to ground. When an open-circuited stub is used, when its electrical length is equal to 90 degrees at the second harmonic, the impedance transformation from open circuit to short circuit can be achieved. In addition, the defective ground structure and defective microstrip structure are essentially a kind of LC resonant circuit. When their equivalent inductance and capacitance values ​​meet (Among them, L equal Indicates the equivalent inductance value in the defective ground structure or defective microstrip structure, C equal When represents the equivalent capacitance value in a defective ground structure or a defective microstrip structure), the second harmonic can be short-circuited to ground.

[0057] In an optional embodiment, the resonant frequency of the first notch network is twice the minimum value at the second harmonic of the operating frequency of the power amplifier tube;

[0058] The resonant frequency of the second notch network is twice the maximum value of the second harmonic of the operating frequency of the power amplifier tube.

[0059] In some embodiments, the resonant frequencies of the first notch network and the second notch network are respectively set at the second harmonic frequencies 2F1 and 2F2 of the upper and lower operating frequencies, where F1 and F2 represent the operating frequencies of the power amplifier tube. The above settings are intended to reduce the memory effect of the power amplifier.

[0060] The memory effect is one of the important factors affecting the linearity of power amplifiers. It is mainly caused by the second harmonics and other components generated by the power amplifier tube itself. These components will generate intermodulation components of adjacent channels after passing through nonlinear elements, increase the adjacent channel power ratio (ACPR), and deteriorate the linearity index. When the signal bandwidth increases, the power amplifier is insufficient to suppress the second harmonics in the wide band, which will easily lead to further deterioration of the linearity. Therefore, the present application sets different short-circuit resonant frequencies in the input and output notch networks (i.e., the first notch network and the second notch network) so that the transfer function of the power amplifier has two transmission zeros TZ1 and TZ2 near 2F1 and 2F2, thereby forming a wider, flatter and more highly suppressed second harmonic stopband, thereby improving the linearity of the power amplifier in a wide band. The corresponding transmission function diagram is shown in FIG. Figure 8 .

[0061] Based on the above-mentioned related embodiments, the various implementations of the dispersion compensation network and the notch network can be combined in any way in practical applications to achieve the best effect of the power amplifier. Fig. 9 For example, the network structure is entirely implemented using a microstrip structure, which is mainly used in board-level circuits of high-power base station systems that do not require high size. It has the characteristics of good thermal stability, large power capacity and low loss. Fig.10 Another network structure is shown, which is implemented with lumped components and is mainly used in board-level circuits of microwave integrated circuits or mobile phone RF systems to achieve circuit miniaturization.

[0062] In an alternative embodiment, see Fig. 9 and Fig.10 , also includes: DC blocking capacitors and power supply inductors;

[0063] The DC blocking capacitor is connected to the second fundamental matching network and the dispersion compensation network;

[0064] One end of the power supply inductor is connected to the second fundamental wave matching network, and the other end is connected to electricity.

[0065] In some embodiments, a DC blocking capacitor and a power supply inductor may be further provided at the input end of the first fundamental wave matching network.

[0066] In a specific embodiment, the matching structure of the present application can be a low-frequency dispersion matching structure with high notch characteristics, which is arranged at the input and output ends of the power amplifier tube, including a fundamental wave matching network, a notch network and a dispersion compensation network between the power amplifier tube and the output load, and an input notch network and a fundamental wave matching network connected to the input end of the power amplifier tube.

[0067] Among them, the fundamental wave matching network between the power amplifier tube and the output load and the output parasitic capacitance of the power amplifier tube are equivalent to a characteristic impedance of The electrical length of the transmission line is 90 degrees; the input and output notch networks are both resonant circuits, and their resonant frequencies are 2F1 and 2F2 at the second harmonics of the upper and lower operating frequencies, respectively, to achieve a high notch effect of the second harmonic in a wide frequency band; the output dispersion compensation network has a left-handed transmission characteristic, which makes the output impedance of the power amplifier tube equal to the load impedance in a wide frequency band, and the output phase is consistent.

[0068] Among them, the output parasitic capacitance of the power amplifier tube is absorbed and considered in the output fundamental matching network. The input parasitic capacitance of the power amplifier tube is absorbed and considered in the input fundamental matching network.

[0069] The matching structure also includes the possible required DC blocking capacitors and supply inductors, which are absorbed and taken into account in the dispersion compensation network.

[0070] When the power amplifier operates at the best efficiency or maximum output power state, the impedance seen from the root of the power amplifier output end is R opt , and the load impedance at the output end is R L Therefore, the output parasitic capacitance and fundamental wave matching network after the power amplifier tube root should be a characteristic impedance of An equivalent transmission line with an electrical length of 90°.

[0071] Assuming that the operating frequency range of the power amplifier is (F1, F2), the input and output notch networks are resonant circuits with resonant frequencies of 2F1 and 2F2, respectively. This can form a short-circuit effect at the input and output ends of the power amplifier at the second harmonic, filtering out the nonlinear components generated by the parasitic capacitance of the power amplifier tube. In addition, by controlling the resonance of the input and output notch networks at different frequencies, the power amplifier can have two transmission zeros TZ1 and TZ2, generating a wider stopband and higher notch characteristics at the second harmonic, thereby achieving high linearity in a wide frequency band.

[0072] A dispersion compensation network is connected after the notch network at the output end of the power amplifier tube and before the load. The network has a left-hand transmission characteristic of nonlinear dispersion. The frequency dispersion caused by the previous network and the output parasitic capacitance can be compensated by controlling the phase Phase32 between Port3 and Port2, balancing the phase phase31 of the entire power amplifier output end, so that the output impedance converges to the load impedance, thereby playing a role in expanding the bandwidth of the power amplifier. The corresponding power amplifier dispersion compensation principle schematic diagram is shown in Figure 2 shown.

[0073] This application first proposed a low-frequency dispersion matching structure with high notch characteristics. By adding a notch network at the input and output ends, the second harmonic component in a wide band can be filtered out, thereby reducing the linear deterioration caused by the memory effect of the power amplifier; by adding a dispersion compensation network after the power amplifier tube to compensate for the dispersion of the previous stage, the overall output phase of the power amplifier is consistent and the impedance converges. The linearity of the power amplifier in a wide band is improved by notching the second harmonics of the input and output of the power amplifier tube, and the frequency dispersion generated at the output end of the power amplifier tube is compensated to achieve broadband power amplifier, which solves the technical bottleneck of 5G broadband linear power amplifiers and has great practical value for achieving high linearity and broadband power amplifiers.

[0074] Based on the same concept, a power amplifier is provided in an embodiment of the present application, which includes the matching structure and power amplifier tube described in the above-mentioned related embodiments. The specific implementation of the matching structure can refer to the description of the matching structure embodiment part, and the repeated parts will not be repeated.

[0075] The power amplifier in the present application may be, but is not limited to, a microwave power amplifier, which is mainly used in the transmission links of communication equipment such as base stations and mobile phones.

[0076] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0077] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A matching structure, characterized in that: The matching structure is applied to a power amplifier, the power amplifier includes a power amplifier tube, and the matching structure includes: a first fundamental wave matching network, a second fundamental wave matching network and a dispersion compensation network; The first fundamental wave matching network is connected to the input end of the power amplifier tube; The second fundamental wave matching network is connected to the output end of the power amplifier tube; The dispersion compensation network is connected to the second fundamental wave matching network and is used to compensate for the linear frequency dispersion in the power amplifier.

2. The matching structure according to claim 1, characterized in that: Also includes: A first notch network and a second notch network; The first notch network is connected to the input end of the power amplifier tube; The second notch network is connected to the second fundamental wave matching network and the dispersion compensation network; The first notch network is used to perform notch processing on the nonlinear component generated by the input parasitic capacitance of the power amplifier tube, and the second notch network is used to perform notch processing on the nonlinear component generated by the output parasitic capacitance of the power amplifier tube.

3. The matching structure according to claim 2, characterized in that: The first notch network and the second notch network are both resonant circuits, and the resonant frequencies of the two are different.

4. The matching structure according to claim 3, characterized in that: The resonant frequency of the first notch network is twice the minimum value at the second harmonic of the operating frequency of the power amplifier; The resonant frequency of the second notch network is twice the maximum value at the second harmonic of the operating frequency of the power amplifier.

5. The matching structure according to claim 1, characterized in that: The dispersion compensation network adjusts the phases at both ends of the dispersion compensation network by changing its own network parameters so that the target phase produces a frequency offset in the opposite direction to the phase of the preceding network, and the preceding network is a network connected before the input end of the dispersion compensation network.

6. The matching structure according to claim 2, characterized in that: The first notch network and the second notch network include a combination of one or more of a lumped element, a microstrip stub, a defective ground structure, and a defective microstrip structure.

7. The matching structure according to claim 1, characterized in that: The dispersion compensation network includes a combination of one or more of a lumped element and a microstrip structure.

8. The matching structure according to claim 1, characterized in that: When the power amplifier operates at the best efficiency or maximum output power state, the output parasitic capacitance of the power amplifier tube and the impedance of the second fundamental matching network are The equivalent transmission line with an electrical length of 90°, where R opt Represents the equivalent impedance of the output end of the power amplifier tube, R L Represents the load impedance at the output.

9. The matching structure according to claim 1, characterized in that: Also includes: DC blocking capacitors and power supply inductors; The DC blocking capacitor is connected to the second fundamental matching network and the dispersion compensation network; One end of the power supply inductor is connected to the second fundamental wave matching network, and the other end is connected to electricity.

10. A power amplifier, characterized in that: include: The matching structure and power amplifier tube as described in any one of claims 1 to 9.

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