A subway communication signal power amplifier

Abstract

The present invention discloses a subway communication signal power amplifier, comprising: an input matching network, a transistor signal amplification module and an output matching network, wherein the subway communication signal is sequentially amplified through the input matching network, the transistor signal amplification module and the output matching network; the input matching network comprises a first fundamental modulation module and an input harmonic modulation module; the output matching network comprises a second fundamental modulation module and a load harmonic modulation module. The scheme adopts an output stopband network migration method to avoid the transmission zero point of the output network affecting the load impedance matching and improves the in-band performance; combined with a drain power supply switching method, the power amplifier can maintain a high efficiency state at different output powers.

Description

Technical Field

[0001] The invention relates to the technical field of power amplifiers, and in particular to a subway communication signal power amplifier. Background Art

[0002] In subway communication technology, communication signals are an important indicator to ensure driving safety. At present, 5G technology can be used as an important means of subway communication. However, the implementation of 5G technology requires a strong hardware infrastructure. Small base stations are one of the hardware infrastructures for implementing 5G technology. RF power amplifiers are the core components of 5G small base stations and play an important role in small base stations. In order to find an RF power amplifier architecture that can meet the current needs of 5G small base stations, RF power amplifiers based on Doherty architecture have gradually appeared in people's field of vision. The power amplifier of this architecture has higher efficiency and better linearity at the back-off working point, so the Doherty power amplifier has become a hot topic of current research.

[0003] With the rapid development of communication technology, power amplifiers, as the core components of the transmitter, are facing many design challenges while welcoming huge market prospects. How to solve the mutual constraints between conversion efficiency and working bandwidth of power amplifiers has become a key issue facing designers. Summary of the invention

[0004] The present invention provides a subway communication signal power amplifier to solve the above problems existing in the prior art.

[0005] The present invention provides a subway communication signal power amplifier, comprising:

[0006] An input matching network, a transistor signal amplification module and an output matching network, wherein the subway communication signal is sequentially amplified through the input matching network, the transistor signal amplification module and the output matching network;

[0007] The input matching network includes a first fundamental wave modulation module and an input harmonic modulation module; the output matching network includes a second fundamental wave modulation module and a load harmonic modulation module.

[0008] Preferably, the output matching network further includes:

[0009] The optimal impedance solution space module is used to keep the second harmonics of the power amplifier in the pure reactance area of ​​the Smith chart, and the fundamental impedance space is expanded to determine the complex impedance area on the equal resistance circle;

[0010] A common optimal impedance region determination module is used to obtain the efficiency of the package end face under two drain power supply conditions by using load pulling technology; determine the common optimal impedance region of the two drain power supply conditions; the two drain power supply conditions include: the drain voltages use two different voltages for power supply;

[0011] The boundary determination module is used to combine the impedance area required for different drain voltages with the boundary of the impedance solution space of the extended continuous class, expand the required impedance area, and finally design the load impedance near the common optimal impedance area and confined within the design boundary; the load impedance matching work is completed based on the selected topology structure.

[0012] Preferably, the output matching network also includes: an equivalent parasitic parameter network, which is used to determine the parasitic parameter network of the transistor to obtain the actual value of the output matching network's impedance at the current source end face; the output end of the equivalent parasitic parameter network is connected to the input end of the output matching network, and the equivalent parasitic parameter network obtains the actual impedance value of the output matching network at the current source end face from the current source end face toward the output matching network, and obtains the actual impedance value of the output matching network at the package end face from the package cross section toward the output matching network.

[0013] Preferably, a stop band is set in the input matching network to increase the degree of freedom of the output matching network; the input matching network also includes: a harmonic control circuit and a fundamental matching circuit;

[0014] The harmonic control circuit uses open branch lines at corresponding frequencies of 1.8 GHz and 4.2 GHz to create harmonic short-circuit points on the link; the open branch lines are connected in parallel to the transmission link, and when their resistance is less than a set resistance threshold, they affect the fundamental impedance of the entire input network; the characteristic impedance of the open branch lines is greater than or equal to a set value.

[0015] Preferably, in the input matching network, the drain voltage and current waveforms intuitively show the conduction and harmonic fundamental voltage ratio from the perspective of the waveforms, and the expressions of the drain voltage and current are decomposed to obtain various subcomponents, including: the DC component and the fundamental component of the drain voltage, and the DC component and the fundamental component of the drain current; through the changes of each subcomponent, the actual influence value of the conduction angle and the harmonic fundamental voltage ratio on the power amplifier is obtained, and by comparing and calculating each subcomponent with the theoretical value, the corresponding relationship between the output power and the drain efficiency and the conduction angle and the harmonic fundamental voltage ratio is obtained, and the degree of influence is quantitatively determined through the corresponding relationship.

[0016] Preferably, the transistor signal amplification module comprises: a peak power amplifier and a carrier power amplifier; the carrier power amplifier and the peak power amplifier perform active load modulation on each other in the entire back-off interval, so that the power amplifier is always kept in a high-efficiency state;

[0017] The output matching of the peak power amplifier is combined with the reflection coefficient required by the continuous class B carrier power amplifier; when the resistance value of the peak power amplifier is not infinite, there is a certain impedance solution space to make the carrier power amplifier work in a high-efficiency state.

[0018] Preferably, the impedance transformation requirement is met based on a low-order impedance inversion network by utilizing the auxiliary matching network and the back-off impedance solution space expanded by the continuous class;

[0019] The adopted network structure consists of an inductor and a capacitor, which are respectively connected in series and in parallel in the matching network. The whole structure is a low-order low-pass impedance inverter.

[0020] Preferably, the compensation line of the peak power amplifier branch and the reflection coefficient of the carrier power amplifier branch are adjusted so that the carrier power amplifier is in a continuous impedance solution space range at a set frequency point; after the peak power amplifier and the carrier power amplifier are synthesized, the impedance trajectory of the carrier power amplifier in saturation and back-off states is determined; in the saturated state, the impedance of the carrier power amplifier is within the required target impedance region, and both the carrier power amplifier and the peak power amplifier are in saturated output; in the back-off state, due to the wide bandwidth, the impedance of some frequency points in the low-frequency region is outside the optimal efficiency region, and the impedance trajectory is within the set range.

[0021] Preferably, the equivalent parasitic parameter network is obtained and used to calculate the optimal impedance of the package parameter end face, and the optimal impedance solution space is expanded based on the continuous class mode method to determine the impedance of the power amplifier in the saturation and fallback states.

[0022] Preferably, it also includes: a bias network, the bias network is set to a state where the fundamental wave is open-circuited and the second harmonic is short-circuited; the bias network does not affect the fundamental wave load impedance matching and does not require an additional circuit to achieve the function of harmonic tuning;

[0023] The output matching network of the peak power amplifier is consistent with the output matching network of the carrier power amplifier. The output matching network consists of two parts: a fundamental matching circuit and a harmonic control circuit. The bias network and the auxiliary matching network are both part of the harmonic control network.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention provides a subway communication signal power amplifier, comprising: an input matching network, a transistor signal amplification module and an output matching network, wherein the subway communication signal is sequentially amplified through the input matching network, the transistor signal amplification module and the output matching network; the input matching network comprises a first fundamental modulation module and an input harmonic modulation module; the output matching network comprises a second fundamental modulation module and a load harmonic modulation module. The scheme adopts an output stopband network migration method to avoid the transmission zero point of the output network affecting the load impedance matching and improves the in-band performance; combined with a drain power supply switching method, the power amplifier can maintain a high efficiency state at different output powers.

[0026] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. 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 specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the structure of a subway communication signal power amplifier according to an embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the structure of an equivalent parasitic parameter network in an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the structure of an input matching network in an embodiment of the present invention;

[0032] Figure 4 Schematic diagram of the structure of the auxiliary matching network in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0034] The embodiment of the present invention provides a subway communication signal power amplifier, please refer to Figure 1 , the subway communication signal power amplifier includes:

[0035] An input matching network, a transistor signal amplification module and an output matching network, wherein the subway communication signal is sequentially amplified through the input matching network, the transistor signal amplification module and the output matching network;

[0036] The input matching network includes a first fundamental wave modulation module and an input harmonic modulation module; the output matching network includes a second fundamental wave modulation module and a load harmonic modulation module.

[0037] The working principle of the above technical solution is: the solution adopted in this embodiment is an input matching network, a transistor signal amplification module and an output matching network, and the subway communication signal is amplified in turn through the input matching network, the transistor signal amplification module and the output matching network; the input matching network includes a first fundamental modulation module and an input harmonic modulation module; the output matching network includes: a second fundamental modulation module and a load harmonic modulation module.

[0038] The gate-source capacitance of commonly used RF field effect transistors usually exhibits very serious nonlinear characteristics near the threshold voltage. The hard turn-off of the gate-source capacitance near the threshold voltage is caused by the sudden withdrawal of the carriers in the channel from the shadow area of ​​the gate when the transistor is turned off. When the input voltage is less than the threshold voltage, the gate metallization only has the parasitic capacitance of the depletion layer at the edge of the gate. Taking Class B bias as an example, since the gate-source capacitance will store energy in the non-conducting half cycle of the transistor, it will cause the voltage waveform of the transistor gate to have a spike in the non-conducting part, that is, the gate input signal will be distorted.

[0039] The time-domain nonlinear characteristics of RF field-effect transistors need to be mapped to the frequency domain. The asymmetric distortion in the time domain can be considered as an increase in the second harmonic component of the gate input signal. Through the fundamental modulation module and the input harmonic modulation module, as well as the second fundamental modulation module and the load harmonic modulation module, the relationship between the input second harmonic component and the output power and efficiency is established by analyzing the changes in the actual conduction angle, drain voltage and current waveforms, and the efficiency is improved based on the joint control of the input harmonic and fundamental waves.

[0040] Therefore, the solution provided in this embodiment can adapt to the transmission requirements of different base stations and special equipment, and improve the energy efficiency conversion of the power amplifier. The solution adopts the output stopband network migration method to avoid the transmission zero point of the output network affecting the load impedance matching and improves the in-band performance; combined with the drain power supply switching method, the power amplifier can maintain a high efficiency state at different output powers.

[0041] In another embodiment, the output matching network further includes:

[0042] The optimal impedance solution space module is used to keep the second harmonics of the power amplifier in the pure reactance area of ​​the Smith chart, and the fundamental impedance space is expanded to determine the complex impedance area on the equal resistance circle;

[0043] A common optimal impedance region determination module is used to obtain the efficiency of the package end face under two drain power supply conditions by using load pulling technology; determine the common optimal impedance region of the two drain power supply conditions; the two drain power supply conditions include: the drain voltages use two different voltages for power supply;

[0044] The boundary determination module is used to combine the impedance area required for different drain voltages with the boundary of the impedance solution space of the extended continuous class, expand the required impedance area, and finally design the load impedance near the common optimal impedance area and confined within the design boundary; the load impedance matching work is completed based on the selected topology structure.

[0045] The working principle of the above technical solution is as follows: the solution adopted in this embodiment is an optimal impedance solution space module, which is used to keep the second harmonics of the power amplifier in the pure reactance area in the Smith chart, and the fundamental impedance space is expanded to determine the complex impedance area on the equal resistance circle; a common optimal impedance area determination module is used to obtain the efficiency of the package end face under two drain power supply conditions using load pulling technology; determine the common optimal impedance area of ​​the two drain power supply conditions; the two drain power supply conditions include: the drain voltage uses two different voltage power supply conditions respectively; a boundary determination module is used to combine the impedance area required for different drain voltages with the impedance solution space boundary of the extended continuous class, expand the required impedance area, and finally design the load impedance near the common optimal impedance area and limit it to the design boundary; complete the load impedance matching work based on the selected topology structure.

[0046] The RF power amplifier works in the linear region under the small signal state, and the optimal load impedance at this time is a relatively fixed value. However, as the input voltage continues to increase, the optimal load impedance of the power amplifier working in the nonlinear region will change with the change of the input signal power. Therefore, when designing the matching circuit of the power amplifier in the large signal mode, it is necessary to use the Smith chart to draw the equal output power curve under different load impedances for different RF input powers for each given input power, thereby obtaining the optimal load impedance under maximum output power. This technology is called load pull technology.

[0047] When the RF output power reaches the maximum, the efficiency of the power amplifier also reaches the maximum accordingly. In the power back-off state, as the output power decreases, the efficiency of the amplifier also decreases. The purpose of load-pull technology is to dynamically adjust the load impedance so that the voltage of the amplifier is always in a saturated state, thereby ensuring that high efficiency performance can be maintained under back-off power.

[0048] Although the optimal impedance of the third harmonic is still at infinity in the extended hybrid mode, both the fundamental and second harmonics have variable real and imaginary parts, which further increases the design freedom and provides more convenience for broadband design. The further expansion of the impedance solution space reduces the voltage amplitude, which will affect the final output power and efficiency of the power amplifier, so the appropriate expansion space needs to be considered during design.

[0049] In another embodiment, the output matching network further includes: an equivalent parasitic parameter network, which is used to determine the parasitic parameter network of the transistor to obtain the actual value of the output matching network's impedance at the current source end face; the output end of the equivalent parasitic parameter network is connected to the input end of the output matching network, and the equivalent parasitic parameter network obtains the actual impedance value of the output matching network at the current source end face from the current source end face toward the output matching network, and obtains the actual impedance value of the output matching network at the package end face from the package cross section toward the output matching network.

[0050] The transistor itself is not an ideal current source, and in practice it is often accompanied by parasitic capacitance. Therefore, if the hybrid continuous type technology is used in the power amplifier, the parameters of its internal parasitic and packaging network must be obtained. After obtaining the equivalent parasitic parameter network of the transistor, as long as its inverse network is cascaded at the drain of the transistor, and then the equivalent parasitic parameter network is cascaded, the required current source end face and packaging plane can be obtained. The hybrid continuous type mode has a strict range for the fundamental wave and each harmonic impedance of the power amplifier and requires a one-to-one correspondence between the fundamental wave and the harmonic. However, since the broadband power amplifier of this embodiment spans the octave, it is difficult to ensure that the fundamental wave and the harmonic wave are in the corresponding area and correspond one to one. In this case, since the fundamental wave impedance has a more obvious impact on the performance of the power amplifier, the matching result of the fundamental wave impedance is considered first, and then the distribution of the harmonic impedance is considered. Therefore, the harmonic impedance will be mismatched. Even if the one-to-one correspondence between the harmonic and the fundamental wave cannot be met, the harmonic cannot be allowed to fall in the low-efficiency impedance area, which deteriorates the efficiency of the power amplifier. Therefore, load-pull technology is used to assist the cross-octave power amplifier and design. Through the load-pull technique, the low efficiency area of ​​the second harmonic at the end face of the transistor package can be obtained. Figure 2As shown, the equivalent parasitic parameter network obtains the actual impedance value of the output matching network at the current source end face from the current source end face to the output matching network, and obtains the actual impedance value of the output matching network at the package end face from the package cross section to the output matching network.

[0051] In another embodiment, a stop band is set in the input matching network to increase the degree of freedom of the output matching network; the input matching network further includes: a harmonic control circuit and a fundamental matching circuit;

[0052] The harmonic control circuit uses open branch lines at corresponding frequencies of 1.8 GHz and 4.2 GHz to create harmonic short-circuit points on the link; the open branch lines are connected in parallel to the transmission link, and when their resistance is less than a set resistance threshold, they affect the fundamental impedance of the entire input network; the characteristic impedance of the open branch lines is greater than or equal to a set value.

[0053] Since the stopband design will bring about a transmission zero point, setting it in the output network will directly affect the load impedance matching. Taking a dual-band power amplifier as an example, the performance of this type of power amplifier is because the load impedance formed by the designed output matching network is a continuous curve with respect to frequency. When the interval between the two frequency bands f1 and f2 is wide, there is enough frequency design margin to design a stopband between the two frequency points without affecting the performance of the operating frequency point. However, when f1 and f2 are not wide enough, inserting a stopband design in the output matching network will inevitably interfere with the position and direction of the load impedance line, thereby affecting the performance of the designed frequency point.

[0054] like Figure 3 As shown, Figure 3 It is a schematic diagram of the structure of the input matching network. The two open branch lines and the gate bias line show a 90-degree phase shift at the second harmonics of 0.9, 1.5 and 2.1 GHz, so they achieve harmonic short circuit at points A, B and C in the figure.

[0055] In another embodiment, in the input matching network, the drain voltage and current waveforms show the conduction and harmonic fundamental voltage ratio from the perspective of the waveform, and the expressions of the drain voltage and current are decomposed to obtain various subcomponents, including: the DC component and the fundamental component of the drain voltage, and the DC component and the fundamental component of the drain current; through the changes of each subcomponent, the actual influence of the conduction angle and the harmonic fundamental voltage ratio on the power amplifier is obtained, and by comparing and calculating each subcomponent with the theoretical value, the corresponding relationship between the output power and the drain efficiency and the conduction angle and the harmonic fundamental voltage ratio is obtained, and the degree of influence is quantitatively determined through the corresponding relationship.

[0056] The DC component of the drain current increases with the increase of the conduction angle, which means that the DC power supply increases at this time, and the fundamental wave changes less with the increase of the conduction angle, which eventually leads to a decrease in the efficiency of the power amplifier, while the third harmonic component of the current does not change. Regardless of the conduction angle, the DC component of the drain current will increase significantly with the increase of the harmonic-to-fundamental voltage ratio, while the fundamental component of the drain current decreases or does not change much, which is also a manifestation of the decrease in the efficiency of the entire system.

[0057] In another embodiment, the transistor signal amplification module includes: a peak power amplifier and a carrier power amplifier; the carrier power amplifier and the peak power amplifier perform active load modulation on each other in the entire back-off interval, so that the power amplifier remains in a high-efficiency state;

[0058] The output matching of the peak power amplifier is combined with the reflection coefficient required by the continuous class B carrier power amplifier; when the resistance value of the peak power amplifier is not infinite, the impedance solution space is increased to make the efficiency state of the carrier power amplifier reach the set state.

[0059] The working principle of the above technical solution is: the solution adopted in this embodiment is that the transistor signal amplification module includes: a peak power amplifier and a carrier power amplifier; the carrier power amplifier and the peak power amplifier perform active load modulation on each other in the entire back-off interval, so that the power amplifier remains in a high-efficiency state; the output matching of the peak power amplifier is combined with the reflection coefficient required by the continuous Class B carrier power amplifier; when the resistance value of the peak power amplifier is not infinite, the impedance solution space is increased so that the efficiency state of the carrier power amplifier reaches the set state.

[0060] The equivalent parasitic parameter model of the transistor is extracted by de-embedding technology, and the circuit topology of the continuous-mode power amplifier is constructed. Combined with the proposed post-matching assisted harmonic control method, the design requirements of the load modulation network are simplified.

[0061] In another embodiment, the impedance transformation requirement is met based on a low-order impedance inversion network by utilizing an auxiliary matching network and a continuous-class expanded back-off impedance solution space;

[0062] The adopted network structure consists of an inductor and a capacitor, which are respectively connected in series and in parallel in the matching network, so the whole structure is a low-order-low-pass impedance inverter.

[0063] The working principle of the above technical solution is: the solution adopted in this embodiment is to utilize the back-off impedance solution space expanded by the auxiliary matching network and the continuous class, and meet the impedance transformation requirements based on the low-order impedance inverter network; the network structure adopted is composed of an inductor and a capacitor, and the inductor and the capacitor are respectively connected in series and in parallel in the matching network, so the entire structure is a low-order-low-pass impedance inverter.

[0064] The impedance change trend required for the power amplifier to go from the saturation state to the fallback state, and the design of the impedance inverter needs to be modified according to this change trend. In the design of traditional Doherty power amplifiers, since the impedance inversion network needs to complete a large impedance transformation, a high-order matching network structure is usually used. However, the broadband performance of high-order matching networks is poor, which is also one of the main limiting factors that prevent the bandwidth of traditional Doherty power amplifiers from being expanded. In addition, the high-order matching network has a complex structure, which increases the design cost. The introduction of the auxiliary matching network greatly reduces the impedance transformation ratio required by the matching network itself, thereby alleviating the pressure on the broadband design of the output matching network and making the design of broadband Doherty power amplifiers possible.

[0065] At each operating frequency point, the load impedance of the carrier power amplifier changes from saturation to back-off, the real part changes slightly, but the imaginary part changes significantly. At the same time, all designed impedances are within the target impedance range to be achieved, and the load impedance meets the impedance requirements for saturation and back-off within the design frequency band.

[0066] In another embodiment, the compensation line of the peak power amplifier branch and the reflection coefficient of the carrier power amplifier branch are adjusted so that the carrier power amplifier is in a continuous impedance solution space range at a set frequency point; after the peak power amplifier and the carrier power amplifier are synthesized, the impedance trajectory of the carrier power amplifier in saturation and back-off states is determined; in the saturated state, the impedance of the carrier power amplifier is within the required target impedance region, and both the carrier power amplifier and the peak power amplifier are in saturated output; in the back-off state, due to the wide bandwidth, the impedance of some frequency points in the low-frequency region is outside the optimal efficiency region, and the impedance trajectory is within the set range.

[0067] The working principle of the above technical solution is: the solution adopted in this embodiment is to adjust the compensation line of the peak branch and the reflection coefficient of the carrier power amplifier so that the carrier power amplifier is also near the continuous impedance solution space at the remaining design frequency points; after the two paths are synthesized, the impedance trajectory of the carrier power amplifier in the saturation and back-off states is determined; in the saturated state, the impedance of the carrier power amplifier is within the required target impedance region, and both it and the peak power amplifier are in saturated output; in the back-off state, due to the wide bandwidth, the impedance of some frequency points in the low-frequency region is outside the optimal efficiency region, and the impedance trajectory is within the set range.

[0068] The impedance transformation ratio required by the auxiliary matching network is also determined accordingly, and the design of the auxiliary matching network can be completed based on this transformation ratio. In order to achieve broadband design, the structure of the auxiliary matching network should also be simplified as much as possible. This part of the design is completed using an optimization algorithm. The final auxiliary matching network is as follows: Figure 4 As shown, Figure 4 It is a structural diagram of the auxiliary matching network.

[0069] In another embodiment, the equivalent parasitic parameter network is obtained and used to calculate the optimal impedance of the package parameter end face, and the optimal impedance solution space is expanded based on the continuous class mode method to determine the impedance of the power amplifier in the saturation and back-off states.

[0070] The working principle of the above technical solution is: the solution adopted in this embodiment is to obtain an equivalent parasitic parameter network, use the obtained equivalent parasitic parameter network to calculate the optimal impedance of the package parameter end face, expand the optimal impedance solution space based on the continuous class mode method, and determine the impedance of the power amplifier in the saturation and fallback states.

[0071] The impedance solution space of the continuous class theory is analyzed at the current source end face of the transistor. When using packaged transistors, due to the presence of parasitic parameters, the transistor needs to be de-embedded in the actual design. The gate bias voltage of the transistor is set to -9V to keep the transistor in deep class C, that is, in a completely pinched-off state. Since the corresponding equivalent parasitic parameter network model has been selected, the S parameters of the equivalent parasitic parameter network are approximated to the transistor model through parameter iteration.

[0072] The frequency band of this embodiment is the 5G FR1 n78 frequency band, so the frequency band of the S parameter simulation is selected from the designed frequency band to its second harmonic. Whether it is phase or amplitude, at the designed frequency band and its second harmonic, the extracted S parameters of the equivalent parasitic parameter network and the parameters of the transistor drain are basically consistent, among which there is almost no error in amplitude, the maximum phase error is 4°, and the maximum error is at 4-5GHz, which is outside the frequency range of the fundamental wave and harmonics of this embodiment.

[0073] By building an equivalent parasitic parameter network, the theoretical guidance of the continuous class can be linked to the transistor of the actual unknown packaging network, so that the current source end face and the package end face are mapped one by one.

[0074] In another embodiment, it further includes: a bias network, the bias network is set to a state where the fundamental wave is open circuited and the second harmonic is short circuited; the bias network can achieve the function of harmonic tuning without additional circuits while not affecting the fundamental wave load impedance matching;

[0075] The output matching network of the peak power amplifier is consistent with the carrier branch. The output matching network consists of two parts: a fundamental matching circuit and a harmonic control circuit. The bias network and the auxiliary matching network are both part of the harmonic control network.

[0076] The working principle of the above technical solution is: the solution adopted in this embodiment also includes: a bias network, the bias network is set to a state where the fundamental wave is open and the second harmonic is short-circuited; the bias network can realize the harmonic tuning function without an additional circuit without affecting the fundamental wave load impedance matching; the output matching network of the peak power amplifier is consistent with the carrier branch, the output matching network consists of two parts: a fundamental wave matching circuit and a harmonic control circuit, and the bias network and the auxiliary matching network are both part of the harmonic control network.

[0077] The beneficial effects of the above technical solution are: in order to further improve the in-band gain of the power amplifier, the solution provided by this embodiment is adopted, the equivalent parasitic parameter model of the transistor is extracted by using the de-embedding technology, and the circuit topology of the continuous-mode power amplifier is constructed, and a high-efficiency and high-gain common impedance space is obtained on the package end face. Combined with the proposed post-matching auxiliary harmonic control method, the design requirements of the load modulation network are simplified.

[0078] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A subway communication signal power amplifier, characterized in that: include: An input matching network, a transistor signal amplification module and an output matching network, wherein the subway communication signal is sequentially amplified through the input matching network, the transistor signal amplification module and the output matching network; The input matching network includes a first fundamental modulation module and an input harmonic modulation module; The output matching network includes: a second fundamental wave modulation module and a load harmonic modulation module; The output matching network also includes: The optimal impedance solution space module is used to keep the second harmonics of the power amplifier in the pure reactance area of ​​the Smith chart, and the fundamental impedance space is expanded to determine the complex impedance area on the equal resistance circle; A common optimal impedance region determination module is used to obtain the efficiency of the package end face under two drain power supply conditions by using load pulling technology; determine the common optimal impedance region of the two drain power supply conditions; the two drain power supply conditions include: the drain voltages use two different voltages for power supply; The boundary determination module is used to combine the impedance region required for different drain voltages with the boundary of the impedance solution space of the extended continuous class, expand the required impedance region, and finally design the load impedance near the common optimal impedance region and confined within the design boundary; and complete the load impedance matching work based on the selected topology structure; The output matching network further comprises: an equivalent parasitic parameter network, the equivalent parasitic parameter network is used to determine the parasitic parameter network of the transistor, and obtain the actual value of the impedance of the output matching network at the end face of the current source; the output end of the equivalent parasitic parameter network is connected to the input end of the output matching network, and the equivalent parasitic parameter network obtains the actual impedance value of the output matching network at the end face of the current source from the end face of the current source to the direction of the output matching network, and obtains the actual impedance value of the output matching network at the end face of the package from the direction of the package cross section to the output matching network; A stop band is set in the input matching network to increase the degree of freedom of the output matching network; the input matching network also includes: a harmonic control circuit and a fundamental wave matching circuit; The harmonic control circuit uses open branch lines at corresponding frequencies of 1.8 GHz and 4.2 GHz to create harmonic short-circuit points on the link; the open branch lines are connected in parallel to the transmission link, and when their resistance is less than a set resistance threshold, they affect the fundamental impedance of the entire input network; the characteristic impedance of the open branch lines is greater than or equal to a set value; The transistor signal amplification module includes: a peak power amplifier and a carrier power amplifier; the carrier power amplifier and the peak power amplifier perform active load modulation on each other in the entire back-off interval, so that the power amplifier remains in a high-efficiency state; Combine the output matching of the peak power amplifier with the reflection coefficient required by the continuous class B carrier power amplifier; when the peak power amplifier has a non-infinite resistance value, increase the impedance solution space so that the efficiency state of the carrier power amplifier reaches the set state; By using the auxiliary matching network and the continuous class-expanded back-off impedance solution space, the impedance transformation requirements are met based on the low-order impedance inversion network. The network structure used is composed of an inductor and a capacitor, which are connected in series and in parallel in the matching network respectively. The whole structure is a low-order low-pass impedance inverter. Also included: a bias network, the bias network is set to a state where the fundamental wave is open circuited and the second harmonic is short circuited; the bias network does not affect the fundamental wave load impedance matching and does not require an additional circuit to achieve a harmonic tuning function; The output matching network of the peak power amplifier is consistent with the output matching network of the carrier power amplifier. The output matching network consists of two parts: a fundamental matching circuit and a harmonic control circuit. The bias network and the auxiliary matching network are both part of the harmonic control network.

2. A subway communication signal power amplifier according to claim 1, characterized in that: In the input matching network, the drain voltage and current waveforms show the conduction and harmonic fundamental voltage ratio from the perspective of the waveform. The expressions of the drain voltage and current are decomposed to obtain various subcomponents, including: the DC component and the fundamental component of the drain voltage, and the DC component and the fundamental component of the drain current; through the changes of each subcomponent, the actual influence of the conduction angle and the harmonic fundamental voltage ratio on the power amplifier is obtained, and the corresponding relationship between the output power and the drain efficiency and the conduction angle and the harmonic fundamental voltage ratio is obtained by comparing and calculating each subcomponent with the theoretical value, and the degree of influence is quantitatively determined through the corresponding relationship.

3. The subway communication signal power amplifier according to claim 1, characterized in that: By adjusting the compensation line of the peak power amplifier branch and the reflection coefficient of the carrier power amplifier branch, the carrier power amplifier is placed in a continuous impedance solution space at a set frequency point; after the peak power amplifier and the carrier power amplifier are synthesized, the impedance trajectory of the carrier power amplifier in saturation and back-off states is determined; in the saturated state, the impedance of the carrier power amplifier is located in the required target impedance region, and both the carrier power amplifier and the peak power amplifier are in saturated output; in the back-off state, due to the wide bandwidth, the impedance of some frequency points in the low-frequency region is outside the optimal efficiency region, and the impedance trajectory is within the set range.

4. A subway communication signal power amplifier according to claim 3, characterized in that: By using the obtained equivalent parasitic parameter network, the optimal impedance of the package parameter end face is calculated, and the optimal impedance solution space is expanded based on the continuous class mode method to determine the impedance of the power amplifier in the saturation and back-off states.

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