High-linearity radio frequency amplifier with self-adaptive biasing circuit

Abstract

The invention discloses a high-linearity radio frequency amplifier with a self-adaptive biasing circuit. According to the technical scheme, the high-linearity radio frequency amplifier with the self-adaptive bias circuit comprises a bias voltage reference source circuit, the self-adaptive bias circuit and a radio frequency amplifier body. The bias voltage reference source circuit is adopted to provide bias voltage irrelevant to power supply voltage for the radio-frequency amplifier, it can be guaranteed that an HBT crystal amplifier tube of the amplifier keeps relatively constant transconductance, and the radio-frequency amplifier with relatively constant gain is achieved. The reference voltage following circuit is adopted to provide a bias voltage which is dynamically adjusted along with the change of an input signal for the radio frequency amplifier, so that the problem of gain compression of the radio frequency amplifier when the input power is increased under the low-power-consumption bias voltage is solved, and the linearity of the low-power-consumption radio frequency amplifier is greatly improved. The invention relates to the technical field of radio frequency integrated circuits, in particular to a high-linearity radio frequency amplifier with a self-adaptive biasing circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency integrated circuits, and more specifically, to a high-linearity radio frequency amplifier with an adaptive bias circuit. Background Art

[0002] Radio Frequency (RF) signal amplifiers are an important part of various wireless receivers. RF, that is, Radio Frequency, is usually abbreviated as RF, which represents the electromagnetic frequency that can be radiated into space, and the frequency range is between 300 KHz and 30 GHz. RF is radio frequency electromagnetic wave, which is an abbreviation of a high-frequency alternating current changing electromagnetic wave. The RF signal is the same as the RF concept, that is, the modulated radio wave with a certain transmission frequency. We call the high-frequency electromagnetic wave with long-distance transmission ability RF, and RF technology is widely used in the field of wireless communication. An RF amplifier is a finely tuned amplifier that can amplify the high-frequency signals used in radio communication. Wireless communication systems often need to receive signals with different strengths, and require the amplifiers in the receivers to be able to process signals with different strengths without distortion, and maintain high linearity under large dynamic range input signals, which is very crucial for dealing with complex communication environments.

[0003] In the field of electronic engineering, HBT refers to Heterojunction Bipolar Transistor. This is a special bipolar transistor, and different semiconductor materials are used in its emitter region and base region. Since the emitter junction, that is, the PN junction between the emitter region and the base region forms a heterojunction, this transistor has some unique electrical properties, such as high transconductance, high frequency characteristics, etc. Therefore, HBT has a wide range of applications in radio frequency electronic devices.

[0004] In the design of traditional HBT amplifiers, there are mainly three ways to implement the bias circuit. The first way is that an off-chip circuit provides the bias voltage for the base of each stage of amplifier transistors. One of its disadvantages is that the off-chip circuit needs to provide an accurate bias voltage additionally, which will increase the product cost and reduce the product integration. Second, under the condition of a constant bias voltage, the threshold voltage and mobility of the amplifier transistors will change with temperature, resulting in the deterioration of the amplifier gain and linearity performance. Third, the bias voltage provided for the base of each stage of amplifier transistors cannot be dynamically adjusted following the change of the input signal. The second way is to provide the bias voltage for the base of each stage of amplifier transistors by voltage division of the power supply voltage through resistors or current mirrors with resistive loads. One of its disadvantages is that in order to obtain an accurate bias voltage, an accurate power supply voltage needs to be provided off-chip. Second, under the condition of a constant power supply voltage, the threshold voltage and mobility of the amplifier transistors change with temperature, resulting in the deterioration of the amplifier gain and linearity performance. Third, the bias voltage provided for the base of each stage of amplifier transistors cannot be dynamically adjusted following the change of the input signal. The third way is that an on-chip reference circuit provides a reference voltage to provide a bias voltage independent of the power supply voltage for the base of HBT amplifier transistors, without the need to provide an accurate power supply voltage off-chip. Its disadvantage is that the bias voltage provided for the base of the amplifier transistors cannot be dynamically adjusted following the change of the input signal. Especially when the input signal continuously increases, the effective value of the bias voltage at the base of the HBT amplifier transistors will gradually decrease, resulting in a slow compression of the amplifier gain.

[0005] To avoid the situation that when the input signal continuously increases, the effective value of the bias voltage at the base of the amplifier transistors decreases, resulting in a slow compression of the amplifier gain, the traditional approach is to directly increase the bias voltage of the HBT transistors, but this will greatly increase the power consumption of the amplifier and reduce the back-off efficiency of the amplifier. Therefore, for the application scenario where the input signal power changes significantly, how to design an adaptive bias circuit for a high-linearity RF amplifier is a major challenge in the field of RF integrated circuit design. Summary of the Invention

[0006] The object of the present invention is to provide an on-chip fully integrated adaptive bias circuit applied to a high-linearity RF amplifier to provide a bias voltage independent of the power supply voltage and dynamically adjustable following the change of the input signal for the base of the RF amplifier.

[0007] To achieve the above object, the present invention adopts the following technical solution: a high-linearity radio frequency amplifier with an adaptive bias circuit, comprising: a bias voltage reference source circuit, an adaptive bias circuit, and a radio frequency amplifier. The bias voltage reference source circuit provides a reference voltage Vref independent of the power supply voltage for the adaptive bias circuit, and at the same time provides a bias voltage Vb2 for the adaptive bias circuit; the adaptive bias circuit makes the effective value of the bias voltage Vb1 provided for the radio frequency amplifier always follow the reference voltage Vref through a negative feedback loop.

[0008] The present invention has the following advantages compared with the prior art: all circuits and devices involved in the present invention can be implemented on a chip using HBT technology, with small size, light weight, and low cost. Using a bias voltage reference source circuit to provide a bias voltage independent of the power supply voltage for the radio frequency amplifier can ensure that the HBT crystal amplifier tube of the amplifier maintains a relatively constant transconductance and realizes a radio frequency amplifier with a relatively constant gain. Using a reference voltage follower circuit to provide a bias voltage that dynamically adjusts with the input signal for the radio frequency amplifier solves the problem of gain compression in the radio frequency amplifier under a low-power bias voltage when the input power increases, and greatly improves the linearity of the low-power radio frequency amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of the principle of a traditional radio frequency amplifier with a resistor load bias circuit.

[0010] Figure 2 is a system block diagram of the high-linearity radio frequency amplifier with an adaptive bias circuit of the present invention.

[0011] Figure 3 is a schematic diagram of the principle of the high-linearity radio frequency amplifier with an adaptive bias circuit of the present invention.

[0012] Figure 4 is the comparison between the present invention and Figure 1 in the case of gradually increasing the input radio frequency signal, the simulation result comparison of the DC bias voltage at the base of the amplifier tube.

[0013] Figure 5 is the comparison between the present invention and Figure 1 in the case of gradually increasing the input radio frequency signal, the simulation result comparison of the gain compression characteristics. DETAILED DESCRIPTION OF THE INVENTION

[0014] Refer to Figure 2。In a best embodiment described in the following embodiments, a high-linearity radio frequency amplifier with an adaptive bias circuit includes: a bias voltage reference source circuit, an adaptive bias circuit, and a radio frequency amplifier connected in parallel between a common terminal GND and a power supply terminal VDD. The reference voltage Vref output terminal of the bias voltage reference source circuit is connected to the reference voltage Vref input terminal of the adaptive bias circuit; the bias voltage Vb2 output terminal of the bias voltage reference source circuit is connected to the bias voltage Vb2 input terminal of the adaptive bias circuit; the bias voltage Vb1 output terminal of the adaptive bias circuit is connected to the bias voltage Vb1 input terminal of the radio frequency amplifier.

[0015] Refer to Figure 3。The bias voltage reference source circuit includes HBT transistors Q1, Q2, Q3, Q4, Q5, resistor R1, the reference voltage Vref output terminal of the bias voltage reference source circuit, and the bias voltage Vb2 output terminal of the bias voltage reference source circuit. Among them, the collector of HBT transistor Q1 is connected to the collector of HBT transistor Q4, the base of HBT transistor Q4, the base of HBT transistor Q5, and the reference voltage Vref output terminal of the bias voltage reference source circuit. The base of HBT transistor Q1 is connected to the base of HBT transistor Q2, the emitter of HBT transistor Q3, and the bias voltage Vb2 output terminal of the bias voltage reference source circuit. The emitter of HBT transistor Q1 is connected to the power supply terminal VDD. The collector of HBT transistor Q2 is connected to the base of HBT transistor Q3 and the collector of HBT transistor Q5. The base of HBT transistor Q2 is connected to the base of HBT transistor Q1, the emitter of HBT transistor Q3, and the bias voltage Vb2 output terminal of the bias voltage reference source circuit. The emitter of HBT transistor Q2 is connected to the power supply terminal VDD. The collector of HBT transistor Q3 is connected to the bases of HBT transistors Q1 and Q2 and the bias voltage Vb2 output terminal of the bias voltage reference source circuit. The base of HBT transistor Q3 is connected to the collector of HBT transistor Q2. The emitter of HBT transistor Q3 is connected to the common terminal GND. The collector of HBT transistor Q4 is connected to the base of HBT transistor Q4, the collector of HBT transistor Q1, the base of HBT transistor Q5, and the reference voltage Vref output terminal of the bias voltage reference source circuit. The emitter of HBT transistor Q4 is connected to the common terminal GND. The collector of HBT transistor Q5 is connected to the base of HBT transistor Q3 and the collector of HBT transistor Q2. The base of HBT transistor Q5 is connected to the base of HBT transistor Q4, the collector of HBT transistor Q4, the collector of HBT transistor Q1, and the reference voltage Vref output terminal of the bias voltage reference source circuit. The emitter of HBT transistor Q5 is connected to one end of resistor R1. One end of resistor R1 is connected to the emitter of HBT transistor Q5, and the other end of resistor R1 is connected to the common terminal GND.

[0016] For the bias voltage reference source circuit, transistors Q1 and Q2 with their bases connected back-to-back, and their emitters connected to the power supply terminal VDD. Transistors Q1 and Q2 with the same size form a current mirror to force the currents flowing through the collectors of transistors Q4 and Q5 to be equal. Q3 serves as an auxiliary transistor to improve the accuracy of the current replication ratio of the current mirror formed by Q1 and Q2.

[0017] Refer to Figure 3。An adaptive bias circuit, including HBT transistors Q6, Q8, Q9, Q10, Q11, Q12, Q13, Q14, Q15, resistors R2, R3, R4, capacitor C3, a reference voltage Vref input terminal of the adaptive bias circuit, a bias voltage Vb2 input terminal of the adaptive bias circuit, and a bias voltage Vb1 output terminal of the adaptive bias circuit. Among them, the collector of HBT transistor Q8 is connected to the emitters of HBT transistors Q9 and Q10, the base of HBT transistor Q8 is connected to the bases of HBT transistors Q14 and the bias voltage Vb2 input terminal of the adaptive bias circuit, and the emitter of HBT transistor Q8 is connected to the power supply terminal VDD; the collector of HBT transistor Q9 is connected to the bases of HBT transistors Q11 and Q12, the base of HBT transistor Q9 is connected to one end of resistor R2, and the emitter of HBT transistor Q9 is connected to the collector of HBT transistor Q8 and the emitters of HBT transistors Q10; the collector of HBT transistor Q10 is connected to the bases of HBT transistors Q15 and Q13 and one end of capacitor C3, the base of HBT transistor Q10 is connected to one end of resistor R3, and the emitter of HBT transistor Q10 is connected to the collector of HBT transistor Q8 and the emitters of HBT transistors Q9; the collector of HBT transistor Q11 is connected to the power supply terminal VDD, the base of HBT transistor Q11 is connected to the collectors of HBT transistors Q9 and Q12, and the emitter of HBT transistor Q11 is connected to the bases of HBT transistors Q12 and Q13; the collector of HBT transistor Q12 is connected to the bases of HBT transistors Q11 and Q9, the base of HBT transistor Q12 is connected to the emitters of HBT transistors Q11 and Q13, and the emitter of HBT transistor Q12 is connected to the common terminal GND; the collector of HBT transistor Q13 is connected to the bases of HBT transistors Q15 and Q10 and one end of capacitor C3, the base of HBT transistor Q13 is connected to the emitters of HBT transistors Q11 and Q12, and the emitter of HBT transistor Q13 is connected to the common terminal GND; the collector of HBT transistor Q14 is connected to the collectors of HBT transistors Q15, the base of HBT transistor Q6, and the other end of capacitor C3, the base of HBT transistor Q14 is connected to the base of HBT transistor Q8 and the bias voltage Vb2 input terminal of the adaptive bias circuit, and the emitter of HBT transistor Q14 is connected to the power supply terminal VDD;The collector of HBT transistor Q15 is connected to the collector of HBT transistor Q14, the base of HBT transistor Q6, and the other end of capacitor C3. The base of HBT transistor Q15 is connected to the collector of HBT transistor Q10, the collector of HBT transistor Q13, and one end of capacitor C3. The emitter of HBT transistor Q15 is connected to the common terminal GND. The collector of HBT transistor Q6 is connected to the power supply terminal VDD. The base of HBT transistor Q6 is connected to the collector of HBT transistor Q14, the collector of HBT transistor Q15, and the other end of capacitor C3. The emitter of HBT transistor Q6 is connected to one end of resistor R4. One end of resistor R2 is connected to the base of HBT transistor Q9, and the other end is connected to the reference voltage Vref input terminal of the adaptive bias circuit. One end of resistor R3 is connected to the base of HBT transistor Q10, and the other end is connected to the other end of resistor R4 and the bias voltage Vb1 output terminal of the adaptive bias circuit. One end of resistor R4 is connected to the emitter of HBT transistor Q6, and the other end is connected to the other end of resistor R3 and the bias voltage Vb1 output terminal of the adaptive bias circuit. One end of capacitor C3 is connected to the collector of HBT transistor Q13, the base of HBT transistor Q15, and the collector of HBT transistor Q10, and the other end of capacitor C3 is connected to the base of HBT transistor Q6, the collector of HBT transistor Q14, and the collector of HBT transistor Q15.

[0018] For the adaptive bias circuit, transistors Q12 and Q13 with their bases connected back-to-back have their emitters connected to the common terminal GND line. Transistors Q12 and Q13 with the same size form a current mirror to force the currents flowing through the collectors of transistors Q9 and Q10 to be equal. Transistor Q11 serves as an auxiliary transistor to improve the accuracy of the current replication ratio of the current mirror formed by Q12 and Q13.

[0019] Refer to Figure 3。The RF amplifier includes an HBT transistor Q7, an inductor L1, a capacitor C1, a capacitor C2, an RF signal input terminal RFin, an RF signal output terminal RFout, and a bias voltage Vb1 input terminal of the RF amplifier. Among them, the collector of the HBT transistor Q7 is connected to one end of the inductor L1 and one end of the capacitor C2, the base of the HBT transistor Q7 is connected to one end of the capacitor C1 and the bias voltage Vb1 input terminal of the RF amplifier, and the emitter of the HBT transistor Q6 is connected to the common terminal GND; one end of the inductor L1 is connected to the collector of the HBT transistor Q7 and one end of the capacitor C2, and the other end of the inductor L1 is connected to the power supply terminal VDD; one end of the capacitor C1 is connected to the base of the HBT transistor Q7 and the bias voltage Vb1 input terminal of the RF amplifier, and the other end of the capacitor C1 is connected to the RF signal input terminal RFin; one end of the capacitor C2 is connected to the collector of the HBT transistor Q7 and one end of the inductor L1, and the other end of the capacitor C2 is connected to the RF signal output terminal RFout.

[0020] Based on the above circuit structure, the working mechanism of the high-linearity RF amplifier with an adaptive bias circuit of the present invention is as follows: When the RF input signal is small, the Vb1 of the bias voltage is equivalent to the reference voltage Vref provided by the bias voltage reference source circuit; as the RF input signal gradually increases, the effective value of the Vb1 of the bias voltage will gradually decrease to be less than Vref. At this time, the base voltage of the HBT transistor Q15 in the adaptive bias circuit will decrease, driving the base voltage of the HBT transistor Q6 in the adaptive bias circuit to increase, thereby increasing the emitter current of the HBT transistor Q6, and finally raising Vb1 to a level equivalent to Vref.

[0021] Refer to Figure 4 。To verify the above mechanism, the present invention has carried out a simulation comparison of the bias voltage with the Figure 1 RF amplifier a therein. When the input RF signal gradually increases, the DC bias voltage Vb1 remains constant all the time, while the DC bias voltage Vb1a gradually decreases.

[0022] Refer to Figure 5 。To verify the improvement of the linearity performance of the present invention, the present invention has carried out a simulation comparison of the gain compression with the Figure 1 RF amplifier a therein. The RF amplifier a shows gain compression when the input RF signal is greater than -30 dBm, while the RF amplifier described in the present invention shows gain compression when the input RF signal is greater than -15 dBm.

[0023] In summary, the present invention uses a bias voltage reference source circuit to provide a bias voltage independent of the power supply voltage for the radio frequency amplifier, which can ensure that the HBT crystal amplifier of the amplifier maintains a relatively constant transconductance and realizes a radio frequency amplifier with a relatively constant gain. The reference voltage follower circuit is used to provide a bias voltage for the radio frequency amplifier that dynamically adjusts with the input signal, solving the problem of gain compression in the radio frequency amplifier under a low-power bias voltage when the input power increases, and greatly improving the linearity of the low-power radio frequency amplifier.

[0024] Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined by the present invention can be implemented in other embodiments without departing from the spirit or scope of the present invention. The scope of the present invention is not limited to the specific technical solutions described. Any technical solution obtained by making the same or equivalent substitutions for the technical elements in the described specific technical solutions or any technical solution that can be obtained by those skilled in the art without creative labor based on the described specific technical solutions shall be regarded as falling within the protection scope of the present invention.

Claims

1. A high linearity radio frequency amplifier with an adaptive bias circuit, characterized in that: It includes a bias voltage reference source circuit, an adaptive bias circuit and a radio frequency amplifier connected in parallel between a common terminal GND and a power supply terminal VDD; The reference voltage Vref output terminal of the bias voltage reference source circuit is connected to the reference voltage Vref input terminal of the adaptive bias circuit; The bias voltage Vb2 output terminal of the bias voltage reference source circuit is connected to the bias voltage Vb2 input terminal of the adaptive bias circuit; The bias voltage Vb1 output terminal of the adaptive bias circuit is connected to the bias voltage Vb1 input terminal of the radio frequency amplifier.

2. The bias voltage reference source circuit according to claim 1, characterized in that: It includes an HBT transistor Q1, an HBT transistor Q2, an HBT transistor Q3, an HBT transistor Q4, an HBT transistor Q5, a resistor R1, a reference voltage Vref output terminal of a bias voltage reference source circuit, and a bias voltage Vb2 output terminal of the bias voltage reference source circuit; The collector of the HBT transistor Q1 is connected to the collector of the HBT transistor Q4, the base of the HBT transistor Q4, the base of the HBT transistor Q5, and the reference voltage Vref output terminal of the bias voltage reference source circuit, the base of the HBT transistor Q1 is connected to the base of the HBT transistor Q2, the emitter of the HBT transistor Q3, and the bias voltage Vb2 output terminal of the bias voltage reference source circuit, and the emitter of the HBT transistor Q1 is connected to the power supply terminal VDD; The collector of the HBT transistor Q2 is connected to the base of the HBT transistor Q3 and the collector of the HBT transistor Q5, the base of the HBT transistor Q2 is connected to the base of the HBT transistor Q1, the emitter of the HBT transistor Q3, and the bias voltage Vb2 output terminal of the bias voltage reference source circuit, and the emitter of the HBT transistor Q2 is connected to the power supply terminal VDD; The collector of the HBT transistor Q3 is connected to the bases of the HBT transistors Q1 and Q2 and the bias voltage Vb2 output terminal of the bias voltage reference source circuit, the base of the HBT transistor Q3 is connected to the collector of the HBT transistor Q2, and the emitter of the HBT transistor Q3 is connected to the common terminal GND; The collector of the HBT transistor Q4 is connected to the base of the HBT transistor Q4, the collector of the HBT transistor Q1, the base of the HBT transistor Q5, and the reference voltage Vref output terminal of the bias voltage reference source circuit, and the emitter of the HBT transistor Q4 is connected to the common terminal GND; The collector of the HBT transistor Q5 is connected to the base of the HBT transistor Q3 and the collector of the HBT transistor Q2, the base of the HBT transistor Q5 is connected to the base of the HBT transistor Q4, the collector of the HBT transistor Q4, the collector of the HBT transistor Q1, and the reference voltage Vref output end of the bias voltage reference source circuit, and the emitter of the HBT transistor Q5 is connected to one end of the resistor R1; One end of the resistor R1 is connected to the emitter of the HBT transistor Q5 , and the other end of the resistor R1 is connected to the common terminal GND.

3. The adaptive bias circuit according to claim 1, wherein: Includes HBT transistor Q6, HBT transistor Q8, HBT transistor Q9, HBT transistor Q10, HBT transistor Q11, HBT transistor Q12, HBT transistor Q13, HBT transistor Q14, HBT transistor Q15, resistor R2, resistor R3, resistor R4, capacitor C3, reference voltage Vref input terminal of adaptive bias circuit, bias voltage Vb2 input terminal of adaptive bias circuit, bias voltage Vb1 output terminal of adaptive bias circuit; The collector of the HBT transistor Q8 is connected to the emitter of the HBT transistor Q9 and the emitter of the HBT transistor Q10, the base of the HBT transistor Q8 is connected to the base of the HBT transistor Q14 and the bias voltage Vb2 input terminal of the adaptive bias circuit, and the emitter of the HBT transistor Q8 is connected to the power supply terminal VDD; The collector of the HBT transistor Q9 is connected to the base of the HBT transistor Q11 and the collector of the HBT transistor Q12, the base of the HBT transistor Q9 is connected to one end of the resistor R2, and the emitter of the HBT transistor Q9 is connected to the collector of the HBT transistor Q8 and the emitter of the HBT transistor Q10; The collector of the HBT transistor Q10 is connected to the base of the HBT transistor Q15, the collector of the HBT transistor Q13, and one end of the capacitor C3, the base of the HBT transistor Q10 is connected to one end of the resistor R3, and the emitter of the HBT transistor Q10 is connected to the collector of the HBT transistor Q8 and the emitter of the HBT transistor Q9; The collector of the HBT transistor Q11 is connected to the power supply terminal VDD, the base of the HBT transistor Q11 is connected to the collector of the HBT transistor Q9 and the collector of the HBT transistor Q12, and the emitter of the HBT transistor Q11 is connected to the base of the HBT transistor Q12 and the base of the HBT transistor Q13; The collector of the HBT transistor Q12 is connected to the base of the HBT transistor Q11 and the collector of the HBT transistor Q9, the base of the HBT transistor Q12 is connected to the emitter of the HBT transistor Q11 and the base of the HBT transistor Q13, and the emitter of the HBT transistor Q12 is connected to the common terminal GND; The collector of the HBT transistor Q13 is connected to the base of the HBT transistor Q15, the collector of the HBT transistor Q10, and one end of the capacitor C3, the base of the HBT transistor Q13 is connected to the emitter of the HBT transistor Q11 and the base of the HBT transistor Q12, and the emitter of the HBT transistor Q13 is connected to the common terminal GND; The collector of the HBT transistor Q14 is connected to the collector of the HBT transistor Q15, the base of the HBT transistor Q6, and the other end of the capacitor C3, the base of the HBT transistor Q14 is connected to the base of the HBT transistor Q8 and the bias voltage Vb2 input end of the adaptive bias circuit, and the emitter of the HBT transistor Q14 is connected to the power supply terminal VDD; The collector of the HBT transistor Q15 is connected to the collector of the HBT transistor Q14, the base of the HBT transistor Q6, and the other end of the capacitor C3, the base of the HBT transistor Q15 is connected to the collector of the HBT transistor Q10, the collector of the HBT transistor Q13, and one end of the capacitor C3, and the emitter of the HBT transistor Q15 is connected to the common terminal GND; The collector of the HBT transistor Q6 is connected to the power supply terminal VDD, the base of the HBT transistor Q6 is connected to the collector of the HBT transistor Q14, the collector of the HBT transistor Q15, and the other end of the capacitor C3, and the emitter of the HBT transistor Q6 is connected to one end of the resistor R4; one end of the resistor R2 is connected to the base of the HBT transistor Q9, and the other end of the resistor R2 is connected to the reference voltage Vref input end of the adaptive bias circuit; One end of the resistor R3 is connected to the base of the HBT transistor Q10, and the other end of the resistor R3 is connected to the other end of the resistor R4 and the bias voltage Vb1 output end of the adaptive bias circuit; One end of the resistor R4 is connected to the emitter of the HBT transistor Q6, and the other end of the resistor R4 is connected to the other end of the resistor R3 and the bias voltage Vb1 output end of the adaptive bias circuit; One end of the capacitor C3 is connected to the collector of the HBT transistor Q13, the base of the HBT transistor Q15, and the collector of the HBT transistor Q10, and the other end of the capacitor C3 is connected to the base of the HBT transistor Q6, the collector of the HBT transistor Q14, and the collector of the HBT transistor Q15.

4. The radio frequency amplifier according to claim 1, characterized in that: It includes an HBT transistor Q7, an inductor L1, a capacitor C1, a capacitor C2, a radio frequency signal input terminal RFin, a radio frequency signal output terminal RFout, and a bias voltage Vb1 input terminal of the radio frequency amplifier; The collector of the HBT transistor Q7 is connected to one end of the inductor L1 and one end of the capacitor C2, the base of the HBT transistor Q7 is connected to one end of the capacitor C1 and the bias voltage Vb1 input end of the RF amplifier, and the emitter of the HBT transistor Q7 is connected to the common terminal GND; One end of the inductor L1 is connected to the collector of the HBT transistor Q7 and one end of the capacitor C2, and the other end of the inductor L1 is connected to the power supply terminal VDD; One end of the capacitor C1 is connected to the base of the HBT transistor Q7 and the bias voltage Vb1 input end of the RF amplifier, and the other end of the capacitor C1 is connected to the RF signal input end RFin; One end of the capacitor C2 is connected to the collector of the HBT transistor Q7 and one end of the inductor L1 , and the other end of the capacitor C2 is connected to the radio frequency signal output terminal RFout.

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