CN117811507A - Radio frequency power amplifier and wireless signal transmitting system - Google Patents

Abstract

The application relates to the technical field of radio, in particular to a radio frequency power amplifier and a wireless signal transmitting system, wherein the radio frequency power amplifier comprises a first amplifying branch, an input end and a second amplifying branch, wherein the input end is used for receiving part of signals output by radio frequency output equipment; the input end of the second amplifying branch is used for receiving part of signals output by the radio frequency output equipment; one end of the combined impedance matching circuit is respectively connected with the output end of the first amplifying branch and the output end of the second amplifying branch, and the other end of the combined impedance matching circuit is used for being connected with signal transmitting equipment; wherein in a back-off power state, the combined impedance is matched to powerImpedance of the path is regulated to alpha.R _opt The alpha takes a value of 0.25 to 0.4, and the R _opt The load impedance of the first amplifying branch in the saturated power state. This makes it possible to improve the operation efficiency when the drain voltage is lower.

Description

Radio frequency power amplifier and wireless signal transmitting system

Technical Field

The application relates to the technical field of radio, in particular to a radio frequency power amplifier and a wireless signal transmitting system.

Background

Radio frequency power amplifiers are one of the most important components in radio frequency front-end systems, and amplifiers have found wide use in existing communication systems. In order to meet the requirements of high power, high efficiency and miniaturization, as shown in fig. 1, fig. 1 is a schematic circuit diagram of a radio frequency power amplifier in the prior art, and the radio frequency power amplifier can realize high-efficiency operation from back-off power to saturated power.

The first amplifying branch 101 and the second amplifying branch 102 each comprise a transistor, the radio frequency input signal is connected to the input end of the amplifying unit through a power divider and a phase shifter, the output end comprises an impedance transformer and a drain voltage bias network, the impedance of the combining point of the output ends of the first amplifying branch 101 and the second amplifying branch 102 is a specific impedance, so that the load traction condition required by the radio frequency power amplifier is realized, and the current circuit architecture is suitable for working under the fixed drain voltage bias condition.

The 5G system, the bluetooth system, the WIFI system, and the like have low power operation scenes in which it is necessary to reduce the operation voltage (drain voltage) of the transistor to reduce the output power and the power consumption. As shown in fig. 2, fig. 2 is a diagram illustrating the operation efficiency of the rf power amplifier in different power scenarios in the prior art. As can be seen from fig. 2, the normal operating voltage of the corresponding transistor under the high power curve 201 is the first point 203, the operating voltage of the corresponding transistor under the high power curve 201 is the third point 205 under the signal modulation of the low power consumption operating scene, and the operating efficiencies corresponding to the first point 203 and the third point 205 are both higher than 50%; the normal operating voltage of the transistor corresponding to the low power curve 202 (e.g. during night operation) is the second point 204, the corresponding operating efficiency is still higher than 50%, the operating voltage of the transistor corresponding to the low power curve 202 is the fourth point 206 under the signal modulation in the low power operating scenario, and the corresponding operating efficiency is lower than 50%, even lower than 20%, so that the rf power amplifier consumes more dc power.

Disclosure of Invention

In order to solve one of the technical drawbacks, an embodiment of the present application provides a radio frequency power amplifier and a wireless signal transmitting system, where the technical scheme is as follows:

according to a first aspect of embodiments of the present application, there is provided a radio frequency power amplifier, the radio frequency power amplifier comprising,

the input end of the first amplifying branch is used for receiving part of signals output by the radio frequency output equipment; the input end of the second amplifying branch is used for receiving part of signals output by the radio frequency output equipment; one end of the combined impedance matching circuit is respectively connected with the output end of the first amplifying branch and the output end of the second amplifying branch, and the other end of the combined impedance matching circuit is used for being connected with signal transmitting equipment; wherein the combined impedance matching circuit adjusts the combined impedance to alpha R in a back-off power state _opt The alpha takes a value of 0.25 to 0.4, and the R _opt Is the load impedance of the first amplification branch in the saturated power state.

According to a second aspect of embodiments of the present application, there is provided a wireless signal transmission system including:

radio frequency output equipment and signal transmitting equipment; the radio frequency power amplifier is respectively connected with the radio frequency output equipment and the signal transmitting equipment.

By adopting the radio frequency power amplifier provided by the embodiment of the application, the first amplifying branch and the second amplifying branch are adopted to amplify the signals, the signals are output by utilizing the combined impedance matching circuit, and the combined impedance matching circuit adjusts the combined impedance alpha R under the back-off power _opt The value of alpha is 0.25-0.4, so that the impedance of the first amplifying branch is larger, and the improvement of the working efficiency in the backspacing state can be realized under the condition that the drain voltage is lower.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

FIG. 1 is a schematic circuit diagram of a prior art RF power amplifier;

FIG. 2 is a graph of the efficiency of a prior art RF power amplifier under different power scenarios;

FIG. 3 is a schematic diagram of an RF power amplifier;

fig. 4 is a schematic diagram of yet another configuration of a radio frequency power amplifier;

FIG. 5 is a schematic diagram of the working states of the first amplifying branch and the second amplifying branch;

FIG. 6 is a graph of experimental control obtained using the solution of the present application;

fig. 7 is a further experimental control chart obtained by adopting the technical scheme of the application.

Detailed Description

In order to make the technical solutions and advantages of the embodiments of the present application more apparent, the following detailed description of exemplary embodiments of the present application is given with reference to the accompanying drawings, and it is apparent that the described embodiments are only some of the embodiments of the present application and not exhaustive of all the embodiments. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

Radio frequency power amplifiers are increasingly being developed towards high power, high efficiency and miniaturization as an important component of wireless communications. As shown in fig. 1, the radio frequency power amplifier encapsulates two transistors in the same carrier in parallel, and can realize efficient operation from back-off power to saturated power by adapting a proper combining and synthesizing circuit network. However, the rf power amplifier needs to reduce the operating voltage (drain voltage) of the transistor to reduce the output power and power consumption in the face of an operating scenario with low power such as a 5G system, a bluetooth system, and a WIFI system.

As shown in fig. 2, fig. 2 shows an operational efficiency diagram of a conventional rf power amplifier in high power and low power scenarios. The drain voltage is larger under high power operation, for example, in order to maintain the intensity of wireless signals in daytime, the drain voltage needs to be larger; and the intensity of the wireless signal can be reduced at night, thereby reducing the drain voltage. For the high power curve 201, the peak voltage of the rf power amplifier corresponds to the first point 203, but the operating voltage of the rf power amplifier at this time corresponds to the third point 205 under modulation of, for example, a 5GNR modulation signal. At this time, the operating efficiency of both the first point 203 and the third point 205 is maintained at a high level (typically greater than 50%). For the low power curve 202, the voltage of the rf power amplifier corresponds to the second point 204, but the operating voltage of the rf power amplifier at this time corresponds to the fourth point 206 under modulation of, for example, a 5GNR modulation signal. However, at this time, the working efficiency corresponding to the fourth point 206 is significantly lower.

In the present application, a radio frequency power amplifier is provided, as shown in fig. 3 and fig. 4, where fig. 3 is a schematic structural diagram of the radio frequency power amplifier, and fig. 4 is a schematic structural diagram of the radio frequency power amplifier. The rf power amplifier includes a first amplifying branch 101, a second amplifying branch 102 and a combined impedance matching circuit 104, where an input end of the first amplifying branch 101 and an input end of the second amplifying branch 102 may be connected to an output end of the power distribution circuit 105, respectively, and an input end of the power distribution circuit 105 may be connected to an rf output device, so that the first amplifying branch 101 and the second amplifying branch 102 respectively receive a part of signals output by the rf output device. The radio frequency power amplifier may be a Doherty amplifier.

The first amplifying branch 101 amplifies the signal and outputs the signal through the output end of the first amplifying branch 101, and the second amplifying branch 102 amplifies the signal and outputs the signal through the output end of the second amplifying branch 102. The output end of the first amplifying branch 101 and the output end of the second amplifying branch 102 are connected to a combined impedance matching circuit 104, and the combined impedance matching circuit 104 may be connected to a signal transmitting device (not shown), that is, after the signals are amplified by the first amplifying branch 101 and the second amplifying branch 102, the signals are transmitted to the signal transmitting device through the combined impedance matching circuit 104, so that the signals can be received by the user terminal.

In one or more embodiments, the combined impedance matching circuit 104 may adjust the combined impedance to a·r in the back-off power state _opt Wherein alpha is takenThe value is 0.25 to 0.4, R _opt The load impedance of the first amplifying branch in the saturated power state.

In one or more embodiments, the impedance of the combined impedance matching circuit may be adjusted to 1.25 Ω to 32 Ω, i.e., the impedance of the combined impedance matching circuit may include, but is not limited to, 1.5 Ω, 2 Ω, 2.5 Ω, 3.0 Ω, 3.5 Ω, 4.0 Ω, 4.5 Ω, 5.0 Ω, 5.5 Ω, 6.0 Ω, 6.5 Ω, 7.0 Ω, 7.5 Ω, 8.0 Ω, 8.5 Ω, 9.0 Ω, 10.0 Ω, 13.0 Ω, 17.0 Ω, 20.0 Ω, 23.0 Ω, 25.0 Ω, 27.0 Ω, and 30.0 Ω, and in some embodiments, the combined impedance matching circuit 104 may adjust the impedance of the combined impedance matching circuit to 5 Ω to 20 Ω or 12 Ω to 19 Ω.

As shown in fig. 5, fig. 5 is a schematic diagram of the working states of the first amplifying branch and the second amplifying branch. The optimal load impedance of the first transistor is R _opt The maximum power and the efficiency of the first transistor under the saturated power can be ensured to work; the optimal load impedance of the second transistor is R _optA The maximum power and the efficiency of the auxiliary transistor under saturated power can be ensured. R is equal to the maximum power level of the two transistors _opt ＝R _optA Otherwise satisfy: maximum power of the first transistor: maximum power of second transistor=r _optA :R _opt 。

In the high power state (i.e., saturated power state): the first transistor and the second transistor are operated at full power, the combined impedance is modulated by two paths of current, and the impedance of the first amplifying branch is R _opt And provides a load R for the first transistor after the first microstrip line conversion _opt The method comprises the steps of carrying out a first treatment on the surface of the At the second amplifying branch impedance of R _optA And provides a load R for the second transistor after microstrip line conversion _optA The method comprises the steps of carrying out a first treatment on the surface of the Thus, for example, a peak in efficiency corresponding to the first point 203 in FIG. 2 may be achieved; and may, for example, achieve a peak in efficiency corresponding to the second point 204 in fig. 2.

In a low power state (i.e., a back-off power state): the second transistor is not opened, the equivalent output impedance is open, and the impedance Z is changed into impedance Z through the second microstrip line _out Parallel to the combining point, the first amplifying branch circuit combines the impedance alpha R according to the microstrip line impedance transformation principle _opt //Z _out Conversion to (1/alpha) R _opt Because the value of alpha is 0.25-0.4, the impedance of the first amplifying branch is higher, and the higher impedance can ensure that the first transistor works with high efficiency under the condition of low power, thereby realizing the efficiency peak corresponding to the third point 205 in fig. 2; and for example, may achieve a peak in efficiency corresponding to fourth point 206 in fig. 2.

It can be seen that the first amplification branch and the second amplification branch are used to amplify the signal, the signal is output by the combined impedance matching circuit, and the combined impedance matching circuit adjusts the combined impedance by α·r under the back-off power _opt The value of alpha is 0.25-0.4, so that the impedance of the first amplifying branch is larger, and the improvement of the working efficiency in the backspacing state can be realized under the condition that the drain voltage is lower.

The output end of the first amplifying branch 101 may include a first output matching circuit outputting an amplified signal, the output end of the second amplifying branch 102 may include a second output matching circuit outputting an amplified signal, and the combined impedance matching circuit 104 is connected to the first output matching circuit and the second output matching circuit, respectively, to receive the amplified signals output by the first output matching circuit and the second output matching circuit, and output the amplified signals to the signal transmitting device.

As shown in fig. 3 and 4, the first output matching circuit includes a first microstrip line 1012, and the second output matching circuit includes a second microstrip line 1022. In one or more embodiments, the electrical length of the first microstrip line 1012 may be 30 ° to 85 °, i.e., the electrical length of the first microstrip line 1012 may include, but is not limited to: 35 °, 40 °, 45 °, 50 °, 55 °, 60 °, 65 °, 70 °, and 75 °. In some embodiments, the electrical length of the first microstrip line 1012 may also be 50 ° to 70 °.

In one or more embodiments, the electrical length of the second microstrip line 1022 is: 120 deg. to 170 deg., i.e., the electrical length of the second microstrip line 1022 may include, but is not limited to: 125 °, 130 °, 135 °, 140 °, 145 °, 150 °, 155 °, 160 °, and 165 °. In some embodiments, the electrical length of the second microstrip line 1022 may also be 140 ° to 160 °.

In the conventional technical scheme, the electrical length of the second microstrip line is 180 degrees, the open circuit is still converted into the open circuit, and the electrical length of the first microstrip line is 90 degrees, the combined impedance alpha R _opt Conversion to (1/α) R _opt The method comprises the steps of carrying out a first treatment on the surface of the In the technical scheme of the application, the electrical length of the first microstrip line is 30-85 degrees, the electrical length of the second microstrip line is 120-170 degrees, and the complex combined impedance (alpha R) _opt //Z _out ) Conversion to (1/alpha) R _opt Thereby further achieving an improvement in the working efficiency.

As shown in fig. 3 and 4, the radio frequency power amplifier further includes a drain bias circuit 103, and one end of the drain bias circuit 103 may be connected to a third power supply (not shown). The first amplifying branch 101 may further include a first transistor 1011, a first gate bias circuit, and a first input matching circuit, where a drain of the first transistor 1011 may be connected to the other end of the drain bias circuit 103, and a drain of the first transistor 1011 may be connected to the first output matching circuit, that is, the drain of the first transistor 1011 is connected to the other end of the drain bias circuit 103 and the first output distribution circuit, respectively, and the third power supply provides a drain voltage to the first transistor 1011 through the drain bias circuit 103. In this embodiment, the drain of the first transistor 1011 is connected to the other ends of the first microstrip line 1012 and the drain bias circuit 103, respectively. The first transistor 1011 may be a field effect transistor, a BJT transistor, a HEMT transistor, a HBT transistor, or the like.

Load impedance R of first amplifying branch in saturated power state _opt Determined by the choice of transistor, the value of which is R _opt ＝VDD/I _max Wherein VDD is the drain DC bias voltage of the transistor, I _max Maximum current for the transistor drain.

The gate of the first transistor 1011 may be connected to the first gate bias circuit, and the gate of the first transistor 1011 may also be connected to one end of the first input matching circuit, that is, the gate of the first transistor 1011 is connected to the first gate bias circuit and the first input matching circuit, respectively. The first gate bias circuit is also connected to a first power supply (not shown) that supplies a gate voltage to the gate of the first transistor 1011 through the first gate bias circuit. The first input matching circuit is further connected to the rf output device, so as to receive a part of the signal output by the rf output device, and send the signal to the first transistor 1011, where the signal is amplified and then output to the first output power distribution circuit.

The first input matching circuit may further include a phase shifter 1013, wherein a phase shift length of the phase shifter 1013 may be a difference between an electrical length of the second microstrip line and an electrical length of the first microstrip line. That is, the phase shift length of the phase shifter 1013 may be 35 ° to 140 °, or 70 ° to 110 °. The phase shift length of the phase shifter 1013 may be the difference between the electrical length of the second microstrip line and the electrical length of the first microstrip line, so as to ensure that the output currents of the two transistors are combined in phase at the combining point under the saturated power, thereby combining the impedance 1/α×r _opt Accurate modulation as R _opt (for the first amplifying circuit) and R _optA (for the second amplifying circuit).

In one or more embodiments, as shown in fig. 3 and 4, the second amplifying branch 102 includes a second transistor 1021, a second gate bias circuit, and a second input matching circuit, where a drain of the second transistor 1021 is connected to the drain bias circuit 103, and a drain of the second transistor 1021 is also connected to the second output matching circuit, that is, the drain of the second transistor 1021 is connected to the drain bias circuit 103 and the second output matching circuit, respectively, and a third power supply supplies a voltage to the drain of the second transistor 1021 through the drain bias circuit 103. The second transistor 1021 may be a field effect transistor, a BJT transistor, a HEMT transistor, an HBT transistor, or the like. And the first transistor 1011 and the second transistor 1021 may be packaged in a transistor chip.

One end of the second gate bias circuit may be connected to a second power supply (not shown), and the other end of the second gate bias circuit may be connected to the gate of the second transistor 1021, the second power supply providing a voltage to the gate of the second transistor 1021 via the second gate bias circuit. One end of the second input matching circuit may be connected to the rf output device, the other end of the second input matching circuit may be connected to the gate of the second transistor 1021, and a signal output from the rf output device may be input to the second transistor 1021 by the second input matching circuit, amplified by the second transistor 1021, and output to the second output matching circuit.

In one or more embodiments, the drain bias circuit 103 may be a voltage adjustable bias circuit. The power state of the rf power amplifier is changed by adjusting the voltages output to the drain of the first transistor 1012 and the drain of the second microstrip line 1022. For example, the first period of time may adjust the voltage at the drain of the first transistor 1012 and the drain of the second microstrip line 1022 to 48V by the drain bias circuit 103; the second period of time may regulate the voltages of the drain of the first transistor 1012 and the drain of the second microstrip line 1022 to 24V by the drain bias circuit 103.

As shown in fig. 4, the rf power amplifier may be formed on the printed circuit board 10, i.e., the respective components of the rf power amplifier are disposed on the printed circuit board 10, and the drain bias circuit 103 may include a via, a voltage adjustment module 1032, and a second filter capacitor 1031. The through hole is disposed on the printed circuit board 10, one end of the voltage regulation module 1032 is connected to a third power supply, the other end of the voltage regulation module 1032 is connected to the first output power distribution circuit (i.e., the first microstrip line 1012), the printed circuit board 10 may further include a third voltage source port 1033, and the third voltage source port 1033 is connected to the third power supply and the voltage regulation module 1032, respectively. That is, the third power supply is connected to the voltage adjusting module 1032 through the third voltage source port 1033, and the voltage of the drain of the first transistor 1011 and the voltage of the drain of the second transistor 1021 are adjusted by the voltage adjusting module 1032.

The first end of the second filter capacitor 1031 is connected with the through hole, and the second end of the second filter capacitor 1031 is connected between the voltage adjusting module and the first output power distribution circuit (i.e., the first microstrip line). The number of the second filter capacitors 1031 may include one or a plurality, for example, 3 or 4. When the second filter capacitance 1031 includes a plurality, the plurality of second filter capacitances are connected in parallel. The second filter capacitor 1031 may be connected in parallel to a ground capacitor, where the rf frequency is equivalently connected to ground, but the dc signal is not connected to ground, and may provide a path for the rf signal to ground, so as to ensure that the subsequent circuit devices and dc voltage source do not affect the operation of the rf signal.

In one or more embodiments, as shown in fig. 4, the combined impedance matching circuit 104 includes a signal output port 1044, a third microstrip line 1041, a first blocking capacitor 1043, and a first filter capacitor 1042. One end of the signal output port 1044 may be connected to a signal transmitting device (not shown), the other end of the signal output port 1044 is connected to a first end of the first blocking capacitor 1043, a second end of the first blocking capacitor 1043 is connected to a second end of the third microstrip line 1041, and the first end of the third microstrip line 1041 is connected to an output end of the first amplifying branch (i.e., the first microstrip line 1012) and an output end of the second amplifying branch (i.e., the second microstrip line 1022), that is, the third microstrip line 1041, the first blocking capacitor 1043, and the signal output port 1044 are sequentially connected to transmit the amplified signal to the signal transmitting device.

The first end of the first filter capacitor 1042 is grounded (i.e. equivalently connected to ground with a via connection), and the second end of the first filter capacitor 1042 is connected to the third microstrip line 1041. The first filter capacitor 1042 may be one or more. When the first filter capacitor 1042 is plural, the plural first filter capacitors are connected in parallel. The first filter capacitor 1042 may be connected in parallel to a ground capacitor, and the rf frequency is equivalently connected to ground, but the dc signal is not connected to the ground, and the first filter capacitor may provide a ground path for the rf signal, so as to ensure that the subsequent circuit device and the dc voltage source do not affect the operation of the rf signal.

In one or more embodiments, as shown in fig. 4, the radio frequency power amplifier further comprises a power splitting circuit 105, the power splitting circuit 105 comprising a resistor 1052 and a power splitter 1052, a first end of the power splitter 1052 being connectable to a radio frequency output device (not shown), a second end of the power splitter 1052 being connectable to the resistor 1052, a third end of the power splitter 1052 being connectable to an input of the first amplification branch 101, and a fourth end of the power splitter 1052 being connectable to an input of the second amplification branch 102. The printed circuit board 10 may also be provided with a signal input port 1053 and the first end of the power divider 1052 may be connected to the radio frequency output device via the signal input port 1053. The key to the rf power amplifier is to design an impedance matching circuit, and in any rf power amplifier, incorrect impedance matching will make the circuit unstable, and at the same time, reduce the circuit efficiency and increase the nonlinear distortion. When designing the power amplifier matching circuit, the matching circuit should meet the requirements of matching, harmonic attenuation, bandwidth, small standing wave, linearity, actual size and the like.

In one or more embodiments, as shown in fig. 4, the first gate bias circuit includes a third filter capacitor 1017, a first feed inductance 1015, and a first voltage source port 1016, a first end of the first feed inductance 1015 is connected to the first voltage source port 1016, a second end of the first feed inductance 1015 is connected to a gate of the first transistor 1011, the first voltage source port 1016 is connected to a first power source, and the first power source supplies power to the gate of the first transistor 1011 through the first voltage source port 1016 and the first feed inductance 1015. The first end of the third filter capacitor 1017 is grounded (i.e., connected to a via), and the second end of the third filter capacitor 1017 is connected between the first voltage source port 1016 and the first end of the first feed inductance 1015. In some embodiments, the first feed inductance 1015 may also be replaced with a resistor.

The third filter capacitor 1017 may be one or more. When the third filter capacitance 1017 is plural, the plural third filter capacitances are connected in parallel. The third filter capacitor 1017 may be connected in parallel to a ground capacitor, where the rf frequency is equivalently connected to ground, but the dc signal is not connected to ground, and may provide a path for the rf signal to ground, so as to ensure that the subsequent circuit devices and dc voltage source do not affect the operation of the rf signal.

In one or more embodiments, as shown in fig. 4, the second gate bias circuit includes a fourth filter capacitor 1027, a second feed inductance 1025, and a second voltage source port 1026, a first end of the second feed inductance 1025 is connected to the second voltage source port 1026, a second end of the second feed inductance 1025 is connected to the gate of the second transistor 1021, the second voltage source port 1026 is connected to a second power supply, and the second power supply supplies power to the gate of the second transistor 1021 through the second voltage source port 1026 and the second feed inductance 1025. The first end of the fourth filter capacitor 1027 is grounded (i.e., connected to a via), and the second end of the fourth filter capacitor 1027 is connected between the second voltage source port 1026 and the first end of the second feed inductance 1025. In some embodiments, the second feed inductance 1025 may also be replaced with a resistor.

The number of the fourth filter capacitors 1027 may be one or plural. When the fourth filter capacitor 1027 is plural, the plural fourth filter capacitors are connected in parallel. The fourth filter capacitor 1027 may be connected in parallel to a ground capacitor, where the rf frequency is equivalently connected to ground, but the dc signal is not connected to ground, and may provide a path for the rf signal to ground, so as to ensure that the subsequent circuit devices and dc voltage source do not affect the operation of the rf signal.

In one or more embodiments, as shown in FIG. 4, the first input matching circuit further includes a second blocking capacitor 1014. A first terminal of the second blocking capacitor 1014 is connected to the phase shifter 1013, and a second terminal of the second blocking capacitor 1014 is connected to the gate of the first transistor 1011. I.e. one end of the phase shifter 1013 is connected to the third end of the power divider 1051 and the other end of the phase shifter 1013 is connected to the first end of the second blocking capacitor 1014.

The second input matching circuit includes a fourth microstrip line 1023 and a third blocking capacitor 1024, one end of the fourth microstrip line 1023 is connected to the fourth end of the power divider 1051, the other end of the fourth microstrip line 1023 is connected to the first end of the third blocking capacitor 1024, and the second end of the third blocking capacitor 1024 is connected to the gate of the second transistor 1021.

For example, between times t1 and t2 (e.g., 21:00-6:00 during night), the drain voltage is reduced to V2 (e.g., 28-36V), while at other times the drain voltage is V1 (e.g., 48V). As shown in fig. 6, fig. 6 is an experimental control chart obtained by adopting the technical scheme of the application. From this, it can be seen that when the drain voltage is V1, the working efficiency is the working efficiency corresponding to the first point 203, and when the 5G modulation signal is modulated, the working efficiency is the working efficiency corresponding to the third point 205, and the efficiency is still kept at a high level (generally > 50%). In a low power scenario (i.e., time t 1-t 2), the drain voltage is reduced to V2, the peak operating efficiency is reduced to the operating efficiency corresponding to the second point 204, and the operating efficiency is the operating efficiency corresponding to the fourth point 206 under modulation of the 5G modulation signal. Therefore, compared with the traditional efficiency, the working efficiency of the technical scheme is greatly improved (> 30%), so that the direct current consumption power in a low power mode is obviously reduced, and the power consumption of the base station can be reduced.

For another example, the drain voltage is reduced to V2 (e.g., between 28 and 36V) between times t1 and t2 (e.g., between 21:00 and 24:00 during the night), the drain voltage is reduced to V3 (e.g., between 14 and 20V) between times t2 and t3 (e.g., between 0:00 and 6:00 during the early morning), and the supply voltage is V1 (e.g., 48V) at other times. As shown in fig. 7, fig. 7 is a further experimental control chart obtained by adopting the technical scheme of the present application.

Unlike fig. 6, fig. 7 shows a V3 curve with a lower drain voltage, where the V3 curve with a lower drain voltage corresponds to the peak operating efficiency of the fifth point 207, and the operating efficiency of the fifth point 208 corresponds to the operating efficiency of the fifth point 208 under modulation of the 5G modulation signal. Therefore, compared with the traditional efficiency, the working efficiency of the technical scheme is greatly improved (for example, more than 20%), so that the direct current consumption power in the extremely low power mode is obviously reduced, and the power consumption of the base station in early morning time can be further reduced.

For another example, a 100W saturated power RF power amplifier may be used in a 3.5GHz MIMO base station system. The saturated power of the first transistor is 40W, the saturated power of the second transistor is 60W, the first transistor and the second transistor can be HEMT transistors based on GaN gallium nitride technology, and the drain voltage is 48V. According to the design principle, the impedance R of the first amplifying branch _opt The impedance R of the second amplifying branch =28.8Ω _opt A=19.2Ω, α=0.4 (conventional scheme), and α=0.3 is selected in this scheme, so the combined impedance is 8.64Ω; according to the calculation, the electrical length of the first microstrip line is 80 DEG, the electrical length of the second microstrip line is 160 DEG, and the phase shift length of the phase shifter is 80 deg.

In this case, the efficiency can be about 70% at saturated power and about 60% at the back-off power in the case where the drain voltage is 48V. Under the condition that the drain voltage is reduced to 24V, the efficiency can reach about 70% under saturated power, and under the condition of back-off power, the efficiency can reach about 45%, and the efficiency is greatly improved, so that high-efficiency work under a low-power scene is realized, and the power consumption is reduced.

The present application also provides a wireless signal transmission system comprising the aforementioned radio frequency power amplifier, a radio frequency output device (not shown) and a signal transmission device (not shown). The radio frequency power amplifier is respectively connected with the radio frequency output device and the signal transmitting device, the radio frequency output device outputs radio frequency signals to the radio frequency power amplifier, the radio frequency power amplifier amplifies the received signals and then outputs the signals to the signal transmitting device, and the signal transmitting device transmits the signals to the user terminal.

In the description of the present application, it should be understood that the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", "a third", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "coupled," "connected," and the like are to be construed broadly, and may be either a fixed connection or a removable connection, for example; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims (10)

1. A radio frequency power amplifier, characterized in that the radio frequency power amplifier comprises,

the input end of the first amplifying branch is used for receiving part of signals output by the radio frequency output equipment;

the input end of the second amplifying branch is used for receiving part of signals output by the radio frequency output equipment;

one end of the combined impedance matching circuit is respectively connected with the output end of the first amplifying branch and the output end of the second amplifying branch, and the other end of the combined impedance matching circuit is used for being connected with signal transmitting equipment;

wherein the combined impedance matching circuit adjusts the combined impedance to alpha R in a back-off power state _opt The alpha takes a value of 0.25 to 0.4, and the R _opt Is the load impedance of the first amplification branch in the saturated power state.

2. The radio frequency power amplifier of claim 1, wherein the output of the first amplification branch comprises a first output matching circuit outputting an amplified signal, and the output of the second amplification branch comprises a second output matching circuit outputting an amplified signal;

the combined impedance matching circuit is respectively connected with the first output matching circuit and the second output matching circuit, and is used for outputting signals amplified by the first amplifying branch and the second amplifying branch; the first output matching circuit comprises a first microstrip line, and the electrical length of the first microstrip line is as follows: 30-85 degrees; the second output matching circuit comprises a second microstrip line, and the electrical length of the second microstrip line is as follows: 120-170 degrees.

3. The radio frequency power amplifier of claim 2, wherein the first microstrip line has an electrical length of: 50-70 degrees; the electrical length of the second microstrip line is as follows: 140-160 deg.

4. A radio frequency power amplifier according to claim 2 or 3, further comprising a drain bias circuit having one end for connection to a third power supply, the first amplification branch further comprising:

the drain electrode of the first transistor is respectively connected with the other ends of the first output matching circuit and the drain electrode bias circuit;

a first gate bias circuit having one end connected to a first power supply and the other end connected to a gate of the first transistor;

one end of the first input matching circuit is used for receiving part of signals output by the radio frequency output device, and the other end of the first input matching circuit is connected with the grid electrode of the first transistor;

the first input matching circuit comprises a phase shifter, and the phase shift length of the phase shifter is the difference between the electrical length of the second microstrip line and the electrical length of the first microstrip line.

5. The radio frequency power amplifier of claim 4, wherein the second amplification branch comprises:

the drain electrode of the second transistor is connected with the second output matching circuit and the other end of the drain electrode bias circuit;

a second gate bias circuit having one end connected to a second power supply and the other end connected to the gate of the second transistor;

and one end of the second input matching circuit is used for receiving part of signals output by the radio frequency output device, and the other end of the second input matching circuit is connected with the grid electrode of the second transistor.

6. The radio frequency power amplifier according to claim 4 or 5, wherein the drain bias circuit is a voltage adjustable bias circuit.

7. The radio frequency power amplifier of claim 6, wherein the radio frequency power amplifier is formed on a printed circuit board, the drain bias circuit comprising:

a through hole disposed on the printed circuit board;

one end of the voltage regulating module is used for being connected with the third power supply, and the other end of the voltage regulating module is connected with the first microstrip line;

and the first end of the second filter capacitor is connected with the through hole, and the other end of the second filter capacitor is connected between the voltage regulating module and the first microstrip line.

8. The radio frequency power amplifier according to any one of claims 1 to 7, wherein the combined impedance matching circuit comprises:

a signal output port for connecting the signal transmitting device;

the first end of the third microstrip line is respectively connected with the output end of the first amplifying branch and the output end of the second amplifying branch;

the first end of the first blocking capacitor is connected with the signal output port, and the second end of the first blocking capacitor is connected with the second end of the third microstrip line;

and the first filter capacitor is grounded at the first end, and the second end is connected with the third microstrip line.

9. The radio frequency power amplifier according to any one of claims 1 to 8, further comprising a power distribution circuit comprising:

a resistor;

the power distributor is characterized in that a first end of the power distributor is connected with the radio frequency output device, a second end of the power distributor is connected with the resistor, a third end of the power distributor is connected with the input end of the first amplifying branch, and a fourth end of the power distributor is connected with the input end of the second amplifying branch.

10. A wireless signal transmission system, the wireless signal transmission system comprising:

radio frequency output equipment and signal transmitting equipment;

the radio frequency power amplifier of any of claims 1 to 9, being connected to the radio frequency output device, the signal transmitting device, respectively.