High-linearity and high-power GaAs HBT power amplifier with power detection function

Abstract

The invention discloses a high-linearity and high-power GaAs HBT (Heterojunction Bipolar Transistor) power amplifier with a power detection function. The high-linearity and high-power GaAs HBT power amplifier comprises a radio frequency path, a bias module and a power detection circuit, the radio frequency path is used for performing power amplification on a radio frequency signal, improving the stability and expanding the bandwidth by using a negative feedback network, and improving the overall linearity by second harmonic suppression; the bias circuit is used for providing bias voltage dynamically changing along with input power for the three-stage amplification circuit, so that the problems of linearity deterioration and current instability caused by a self-heating effect under high-power input of the GaAs HBT transistor are solved, and amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier are improved; and the power detection circuit is used for outputting a direct-current voltage which is positively correlated with the output power so as to realize accurate control on the output power of the power amplifier. According to the invention, negative feedback, dynamic bias and harmonic suppression technologies are fully combined, and the overall linearity of the amplifier is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of analog and radio frequency circuits, and in particular relates to a high-linearity and high-power GaAs HBT power amplifier with power detection. Background Art

[0002] With the growing demand for wireless communications, wireless LANs are being more widely used in various high-speed wireless communication scenarios such as computers, mobile handheld devices, and the Internet of Things. The power amplifier, or PA for short, is a key component in a wireless communication transceiver system, and its function is to amplify the radio frequency signal. The performance parameters of the power amplifier, such as gain, linearity, gain added efficiency, and output power, have a significant impact on the performance of the system. The GaAs HBT process is widely used to make power amplifiers due to its advantages such as high cutoff frequency, high linearity, high efficiency, and high power density.

[0003] When the amplitude of the input signal is large, the nonlinearity of the power amplifier will have a great impact on the amplification effect; in addition, with the continuous improvement of modulation technology, such as quadrature amplitude modulation (QAM) and orthogonal frequency division multiple access (OFDMA), the linearity requirements of the power amplifier are constantly increasing.

[0004] The linearization technologies of power amplifiers generally include: digital pre-distortion, negative feedback, power back-off, dynamic bias and harmonic suppression. Among them, although digital pre-distortion can optimize the linearity of PA at high power output by compensating for the distortion of peak signals in the nonlinear region, it will increase the complexity of the system and the cost is also high; the stability of negative feedback technology is better, but the degree of improvement in linearity is poor; the power back-off method has poor power added efficiency (PAE); while the dynamic bias and harmonic suppression methods improve the linearity of power amplifiers, various indicators such as PAE, bandwidth, and stability have better performance. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention proposes a high-linearity and high-power GaAs HBT power amplifier design with power detection, which fully combines negative feedback, dynamic bias and harmonic suppression technology to improve the overall linearity of the amplifier, and integrates a power detection circuit at the output port to achieve precise control of the amplifier output power.

[0006] The present invention discloses a high-linearity and high-power GaAs HBT power amplifier with power detection, wherein the GaAs HBT power amplifier comprises a radio frequency path, a bias module and a power detection circuit;

[0007] The radio frequency path includes an input matching circuit, a first amplifying unit, a first interstage matching circuit, a second amplifying unit, a second interstage matching circuit, a third amplifying unit, an output matching circuit, a first negative feedback network, a second negative feedback network and an electrostatic protection circuit which are connected in sequence; the input matching circuit, the first amplifying unit, the first interstage matching circuit, the second amplifying unit, the second interstage matching circuit, the third amplifying unit and the output matching circuit are connected in sequence, the first negative feedback network is connected in parallel to the first amplifying unit, and the second negative feedback network is connected in parallel to the second amplifying unit; the radio frequency path is used to power amplify the input radio frequency signal; the electrostatic protection circuit is respectively connected to the first interstage matching circuit, the second interstage matching circuit and the output matching circuit to construct an electrostatic release path;

[0008] The bias module includes a first dynamic linearization bias circuit, a second dynamic linearization bias circuit and a third dynamic linearization bias circuit; two input ends of the first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit are respectively connected to a DC voltage Vref and a DC voltage Vbatt, and output ends of the first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit are respectively connected to input ends of a first amplification unit, a second amplification unit and a third amplification unit, so as to provide a bias voltage that changes dynamically with input power for the first amplification unit, the second amplification unit and the third amplification unit;

[0009] The power detection circuit is connected to the output end of the third amplifying unit and is used to output a DC voltage that is positively correlated with the output power.

[0010] As a preferred example, the first amplifying unit, the second amplifying unit and the third amplifying unit have the same structure, and each amplifying unit includes n-stage parallel transistors [Q1, Q2, ... Q n ]; The transistor triode is a GaAs HBT crystal triode; the size of each transistor triode and the number n of GaAs HBT transistors connected in parallel are selected according to the power requirements set by each level of amplifier.

[0011] As a preferred example, the first negative feedback network and the second negative feedback network have the same structure; each negative feedback network includes a first resistor R connected in sequence F , feedback inductor L F and the first capacitor C F ; The first resistor R F Keep away from feedback inductor L F One end of the first capacitor C is connected to the input end of the corresponding amplification unit. F Keep away from feedback inductor L F One end of is connected to the output end of the corresponding amplifying unit.

[0012] As a preferred example, the input matching circuit includes a first inductor L1, a second inductor L2, a second capacitor C2 and a third capacitor C3; wherein the two ends of the second capacitor C2 are respectively connected to the input end and the output end of the input matching circuit; the first end of the first inductor L1 is connected to the input end of the input matching circuit, and the second end is grounded; the first end of the third capacitor C3 is connected to the output end of the input matching circuit, and the second end is grounded through the second inductor L2.

[0013] As a preferred example, the first inter-stage matching circuit includes a third inductor L3, a fourth inductor L4, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6; wherein the first end of the third inductor L3 and the first end of the fourth capacitor C4 are connected to the input end of the first inter-stage matching circuit; the second end of the third inductor L3 is connected to the first end of the fifth capacitor C5 and the power supply end of the first inter-stage matching circuit; the second end of the fifth capacitor C5 is grounded; the second end of the fourth capacitor C4 is connected to the first end of the fourth inductor L4 and the first end of the sixth capacitor C6; the second end of the fourth inductor L4 is grounded; and the second end of the sixth capacitor C6 is connected to the output end of the first inter-stage matching circuit.

[0014] As a preferred example, the second inter-stage matching circuit includes a fifth inductor L5, a sixth inductor L6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9 and a tenth capacitor C 10 ; wherein the first end of the fifth inductor L5 and the first end of the seventh capacitor C7 are connected to the input end of the second inter-stage matching circuit; the second end of the fifth inductor L5 is connected to the first end of the eighth capacitor C8 and the power supply end of the second inter-stage matching circuit; the second end of the eighth capacitor C8 is grounded; the second end of the seventh capacitor C7 is connected to the first end of the ninth capacitor C9, the first end of the sixth inductor L6, and the tenth capacitor C 10 The first end of the ninth capacitor C9 is connected to the ground; the second end of the sixth inductor L6 is grounded; the tenth capacitor C 10 The second end of is connected to the output end of the second inter-stage matching circuit.

[0015] As a preferred example, the output matching circuit includes a seventh inductor L7, an eighth inductor L8, a ninth inductor L9, a tenth inductor L 10 11th inductor L 11 , 12th inductor L 12 11th capacitor C 11 , the twelfth capacitor C 12 、Thirteenth capacitor C 13 , Fourteenth capacitor C 14 、15th capacitor C 15 and the sixteenth capacitor C 16; The eleventh capacitor C 11 The first end of the twelfth capacitor C 12 The first end of the ninth inductor L9, the first end of the twelfth inductor L 12 The first end of is connected to the input end of the output matching circuit; the eleventh capacitor C 11 The second end of the twelfth capacitor C is connected to the first end of the seventh inductor L7; the second end of the seventh inductor L7 is grounded; 12 The second end of the twelfth inductor L8 is connected to the first end of the eighth inductor L8; the second end of the eighth inductor L8 is grounded; 12 The second end and the sixteenth capacitor C 16 The first end of the output matching circuit is connected to the power supply end; the sixteenth capacitor C 16 The second end of the ninth inductor L9 is connected to the thirteenth capacitor C 13 The first end of the fourteenth capacitor C 14 The first end of the thirteenth capacitor C 13 The second end of the fourteenth capacitor C is grounded; 14 The second end and the tenth inductor L 10 The first end of the eleventh inductor L 11 The first end of the fifteenth capacitor C 15 The first end of the tenth inductor L 10 The second end of the eleventh inductor L is grounded; 11 The second end of the fifteenth capacitor C 15 The second end of is connected to the output end of the output matching circuit.

[0016] As a preferred example, the electrostatic protection circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6; wherein the first diode D1, the second diode D2, the third diode D3, the fourth diode D4 and the fifth diode D5 are forward biased and connected in series, the positive electrode of the first diode D1 is connected to the electrostatic discharge end of the electrostatic protection circuit, and the negative electrode of the fifth diode D5 is grounded; the sixth diode D6 is reverse biased, the positive electrode of the sixth diode D6 is connected to the electrostatic discharge end of the electrostatic protection circuit, and the negative electrode is grounded.

[0017] As a preferred example, the first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit have the same structure;

[0018] Each dynamic linearization bias circuit includes a second resistor R2, a third resistor R3, a fourth resistor R4, a sixteenth capacitor C p, a first transistor T1, a second transistor T2 and a third transistor T3; wherein the base of the first transistor T1 is respectively connected to the base and collector of the second transistor T2, the first end of the second resistor R2, the sixteenth capacitor C p The emitter of the first transistor T1 is connected to the first end of the fourth resistor R4; the collector of the first transistor T1 is connected to the first end of the third resistor R3; the second end of the fourth resistor R4 is connected to the output end of the dynamic linearization bias circuit; the sixteenth capacitor C p The second end of the third transistor T3 is connected to the emitter of the third transistor T3 and is grounded; the base and collector of the third transistor T3 are connected to the emitter of the second transistor T2; the second end of the second resistor R2 is connected to the first input end of the dynamic linearization bias circuit; the second end of the third resistor R3 is connected to the second input end of the dynamic linearization bias circuit; the first input end of the dynamic linearization bias circuit is connected to the power supply terminal V ref The second input terminal of the dynamic linearization bias circuit is connected to the power supply terminal V batt .

[0019] As a preferred example, the power detection circuit includes a seventeenth capacitor C 17 , the eighteenth capacitor C 18 , the seventh diode D p , a fifth resistor R5 and a sixth resistor R6; wherein a seventeenth capacitor C 17 The first end of is connected to the voltage detection input end of the power detection circuit; the seventeenth capacitor C 17 The second end of the seventh diode D p The anode of the seventh diode D p The negative electrode and the eighteenth capacitor C 18 The first end of the eighth capacitor C is connected to the first end of the fifth resistor R5; 18 The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the voltage detection output end of the power amplifier circuit respectively; the second end of the sixth resistor R6 is grounded.

[0020] The beneficial effects of the present invention are:

[0021] First, the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention utilizes a negative feedback network to improve stability and expand bandwidth, and second harmonic suppression to improve overall linearity, and also has an electrostatic protection circuit to protect the overall circuit from being damaged by electrostatic current; in addition, a bias circuit is used to provide a bias voltage that dynamically changes with the input power for the three-stage amplifier circuit to solve the linearity deterioration and current instability problems caused by the self-heating effect under high-power input of the GaAs HBT transistor, improve the overall linearity of the power amplifier, and improve the amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier; thereby fully combining negative feedback, dynamic biasing and harmonic suppression technology to improve the overall linearity of the amplifier.

[0022] Secondly, the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention provides a power detection circuit for outputting a DC voltage that is positively correlated with the output power, so as to achieve precise control of the output power of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The schematic diagram of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention is shown in FIG.

[0024] Figure 2 This is a schematic diagram of the amplification unit of the present invention;

[0025] Figure 3 It is the principle diagram of the negative feedback network of the present invention;

[0026] Figure 4 is a schematic diagram of an input matching circuit of the present invention;

[0027] Figure 5 is a schematic diagram of a first-stage inter-stage matching circuit of the present invention;

[0028] Figure 6 is a schematic diagram of a second inter-stage matching circuit of the present invention;

[0029] Figure 7 is a schematic diagram of an output matching circuit of the present invention;

[0030] Figure 8 It is the principle diagram of the electrostatic protection circuit of the present invention;

[0031] Fig. 9 The schematic diagram of the dynamic linearization bias circuit of the present invention;

[0032] Fig.10 It is the principle diagram of the power detection circuit of the present invention;

[0033] Fig.10 It is the principle diagram of the power detection circuit of the present invention;

[0034] Fig.11 It is an S parameter simulation diagram of the high linearity and high power GaAs HBT power amplifier with power detection of the present invention;

[0035] Fig.12 A simulated amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) distortion diagram of a high-linearity, high-power GaAs HBT power amplifier with power detection according to the present invention;

[0036] Fig.13 It is a second harmonic power simulation diagram of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention;

[0037] Fig.14 It is a simulation diagram of the power detection voltage of the power detection circuit of the present invention changing with the output power;

[0038] Fig.15 It is a simulation diagram of input power (Pin)-output power (Pout) of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention;

[0039] Fig.16 It is a simulation diagram of output power (Pout)-power added efficiency (PAE) of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention;

[0040] Fig.17 It is a simulation diagram of the output power 1dB compression point of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention. DETAILED DESCRIPTION

[0041] The following examples will enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0042] Figure 1 It is a principle block diagram of a high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; in this embodiment, the power amplifier includes a first amplification unit, a second amplification unit, a third amplification unit, an input matching circuit, a first negative feedback network, a second negative feedback network, an input matching circuit, a first inter-stage matching circuit, a second inter-stage matching circuit, an output matching circuit, an electrostatic protection circuit, a first dynamic linearization bias circuit, a second dynamic linearization bias circuit, a third dynamic linearization bias circuit, and a power detection circuit, a total of 14 parts.

[0043] See also Figure 1, each amplification unit includes terminal 1 and terminal 2, each negative feedback network includes terminal 1 and terminal 2, the input matching circuit includes terminal 1 and terminal 2, the matching networks between each stage include terminal 1, terminal 2 and terminal 3, the output matching circuit includes terminal 1, terminal 2 and terminal 3, the electrostatic protection circuit includes terminal 1, each dynamic linearization bias circuit includes terminal 1, terminal 2 and terminal 3, and the power detection circuit includes terminal 1 and terminal 2.

[0044] Among them, one end (signal input end) of the input matching circuit is connected to the input end of the overall circuit; two ends (signal output end) of the input matching circuit are connected to one end (signal input end) of the first-stage amplifying unit, one end (signal output end) of the first-stage negative feedback network and one end (signal input end) of the first-stage dynamic linearization bias circuit; two ends (signal output end) of the first-stage amplifying unit are connected to one end (signal input end) of the first-stage interstage matching network and two ends (signal input end) of the first-stage negative feedback network; two ends (signal output end) of the first-stage interstage matching network are connected to one end (signal input end) of the second-stage amplifying unit, one end (signal output end) of the second-stage negative feedback network and one end (signal input end) of the second-stage dynamic linearization bias circuit; three ends (power supply end) of the first interstage matching circuit are connected to the DC voltage Vdd and one end (static discharge end) of the electrostatic protection circuit; two ends (signal output end) of the second-stage amplifying unit are connected to the second interstage matching circuit. The first terminal (signal input terminal) of the second-stage negative feedback network is connected to the first terminal (signal input terminal) of the third-stage amplification unit and the first terminal (signal input terminal) of the third-stage dynamic linearization bias circuit; the second terminal (signal output terminal) of the second-stage inter-matching circuit is connected to the first terminal (signal input terminal) of the third-stage amplification unit and the first terminal (signal input terminal) of the third-stage dynamic linearization bias circuit; the third terminal (power supply terminal) of the second-stage inter-matching circuit is connected to the DC voltage Vdd and the first terminal (static discharge terminal) of the electrostatic protection circuit; the second terminal (signal output terminal) of the third-stage amplification unit is connected to the first terminal (signal input terminal) of the output matching circuit and the first terminal (voltage detection input terminal) of the power detection circuit; the second terminal (signal output terminal) of the output matching circuit is connected to the output terminal of the overall circuit; the third terminal (power supply terminal) of the output matching circuit is connected to the DC voltage Vdd and the first terminal (static discharge terminal) of the electrostatic protection circuit; the second terminal (voltage detection output terminal) of the power detection circuit is connected to the power detection voltage; the second and third terminals (power supply terminals) of the three-stage dynamic linearization bias circuit are respectively connected to the DC voltage V ref and V batt connected.

[0045] The working principle of the GaAs HBT power amplifier of the present invention is as follows: a radio frequency signal enters the power amplifier through an input end, and then is amplified by a three-stage amplification unit to an output end to output an amplified signal; wherein a radio frequency signal path composed of a first amplification unit, a second amplification unit, a third amplification unit, an input matching circuit, a first inter-stage matching circuit, a second inter-stage matching circuit, an output matching circuit, a first negative feedback network, and a second negative feedback network realizes wide frequency bandwidth signal amplification; a first dynamic linearization bias circuit, a second dynamic linearization bias circuit, and a third dynamic linearization bias circuit respectively provide biases to the first amplification unit, the second amplification unit, and the third amplification unit, and improves the linearity of the power amplifier through the nonlinear compensation characteristics of the active bias, thereby improving the amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier; an electrostatic protection circuit provides an electrostatic release path for the power amplifier, thereby protecting the overall circuit; a power detection circuit is used to output a DC voltage that is positively correlated with the output power, so as to realize precise control of the output power of the power amplifier;

[0046] Figure 2 The schematic diagram of the amplification unit of the present invention; each amplification unit includes n-stage parallel transistors [Q1, ...Q n ]; the transistor triode is a GaAs HBT crystal triode; the size of each GaAsHBT transistor and the number of transistors connected in parallel n are selected according to the power required at each level; in this embodiment, the collector width of each GaAs HBT transistor in the first amplification unit is 2um, the length is 25um, the interpolation index is 2, and the number of transistors connected in parallel is 2; the collector width of each GaAs HBT transistor in the second amplification unit is 2um, the length is 25um, the interpolation index is 2, and the number of transistors connected in parallel is 4; the collector width of each GaAs HBT transistor in the third amplification unit is 3um, the length is 35um, the interpolation index is 3, and the number of transistors connected in parallel is 16.

[0047] Figure 3 The negative feedback network schematic diagram of the present invention; each negative feedback network adopts the same RLC structure, including a resistor R F 、Inductance L F and capacitor C F The resistor R F One end is connected to the 1st end of the negative feedback network; the resistor R F The other end is connected to the inductor L F Connected; inductor L F The other end is connected to two ends of the negative feedback network. By adopting this negative feedback structure, the bandwidth of the power amplifier can be effectively broadened, the flatness of the gain can be improved, and the stability of the circuit can be significantly improved. The negative feedback network not only enhances the performance of the circuit, but also ensures consistency and reliability at different frequencies.

[0048] Figure 4 The input matching circuit schematic diagram of the present invention includes an inductor L1, an inductor L2, a capacitor C2 and a capacitor C3; wherein one end of the inductor L1 and the capacitor C2 is connected to the end 1 of the input matching circuit; the other end of the inductor L1 is grounded; the other end of the capacitor C2 is connected to the capacitor C3 and the end 2 of the input matching circuit; the other end of the capacitor C3 is connected to the inductor L2; the other end of the inductor L2 is grounded; by reasonably selecting the values ​​of each capacitor and inductor, the impedance from the end 2 can be transformed to about 50 ohms, thereby achieving good input impedance matching; this matching can not only reduce the loss of the input signal, but also improve the overall performance of the system, and ensure the high efficiency and stability of signal transmission.

[0049] Figure 5 The first inter-stage matching circuit schematic diagram of the present invention includes an inductor L3, an inductor L4, a capacitor C4, a capacitor C5 and a capacitor C6; wherein one end of the inductor L3 and the capacitor C4 is connected to the end 1 of the first inter-stage matching circuit; the other end of the inductor L3 is connected to the capacitor C5 and the end 3 of the first inter-stage matching circuit; the other end of the capacitor C5 is grounded; the other end of the capacitor C4 is connected to the inductor L4 and the capacitor C6; the other end of the inductor L4 is grounded; the other end of the capacitor C6 is connected to the end 2 of the first inter-stage matching circuit; by reasonably selecting the values ​​of each capacitor and inductor, the impedance from the two ends can be transformed to near the appropriate optimal impedance, forming a good inter-stage impedance matching, reducing the input signal loss, and improving the performance and efficiency of the entire system.

[0050] Figure 6 The schematic diagram of the second inter-stage matching circuit of the present invention includes an inductor L5, an inductor L6, a capacitor C7, a capacitor C8, a capacitor C9 and a capacitor C 10 ; One end of the inductor L5 and the capacitor C7 are connected to the 1 end of the second inter-stage matching circuit; the other end of the inductor L5 is connected to the capacitor C8 and the 3 end of the second inter-stage matching circuit; the other end of the capacitor C8 is grounded; the other end of the capacitor C7 is connected to the capacitor C9, the inductor L6, and the capacitor C 10 The other end of capacitor C9 is grounded; the other end of inductor L6 is grounded; capacitor C 10 The other end is connected to the two ends of the second inter-stage matching circuit; by reasonably selecting the values ​​of each capacitor and inductor, the impedance from the two ends can be transformed to near the appropriate optimal impedance, forming a good inter-stage impedance matching, reducing input signal loss, and improving the performance and efficiency of the entire system.

[0051] Figure 7 The output matching circuit schematic diagram of the present invention includes inductors L7, L8, L9, and L 10 、Inductance L 11 、Inductance L 12 , capacitor C 11 , capacitor C 12 , capacitor C13 , capacitor C 14 , capacitor C 15 , capacitor C 16 ; Wherein the capacitor C 11 , capacitor C 12 , inductor L9, inductor L 12 Connected to terminal 1 of the output matching circuit; capacitor C 11 The other end is connected to the inductor L7; the other end of the inductor L7 is grounded; the capacitor C 12 The other end is connected to the inductor L8; the other end of the inductor L8 is grounded; 12 The other end is connected to the capacitor C 16 , the 3 terminals of the output matching circuit are connected; capacitor C 16 The other end is grounded; the other end of the inductor L9 is connected to the capacitor C 13 , capacitor C 14 Connected; capacitor C 13 The other end is grounded; capacitor C 14 The other end is connected to the inductor L 10 、Inductance L 11 , capacitor C 15 Connected; inductor L 10 The other end is grounded; the inductor L 11 , capacitor C 15 The other end is connected to the 2 ends of the output matching circuit; L9, C 13 and C 14 , L 10 A second-order L-type matching network is formed, and the values ​​of each inductor and capacitor are determined by load pulling to form a good output impedance matching, thereby maximizing the saturated output power and the maximum power added efficiency; C 11 , L7 and C 12 , L8 form a series resonance, the resonant frequency is at the second harmonic, which is used to short-circuit the second harmonic; C 15 , L 11 A parallel resonance is formed, and the resonant frequency is at the second harmonic, which is used to open the second harmonic; the second harmonic suppression function of the output matching circuit improves the overall linearity of the power amplifier.

[0052] Figure 8 The schematic diagram of the electrostatic protection circuit of the present invention includes diodes D1 to D6; wherein diodes D1 to D5 are forward biased and connected in series, the positive electrode of diode D1 is connected to one end of the electrostatic protection circuit, and the negative electrode of diode D5 is grounded; diode D6 is reverse biased, the positive electrode is connected to one end of the electrostatic protection circuit, and the negative electrode is grounded; when static electricity occurs, it is greater than the turn-on voltage, the forward diodes D1 to D5 are turned on, and at the same time, the reverse diode D6 is avalanche-broken and turned on, and the current goes to the ground to protect the internal circuit.

[0053] Fig. 9The schematic diagram of the dynamic linearization bias circuit of the present invention; the bias circuit includes a resistor R2, a resistor R3, a resistor R4, a capacitor C p , transistor T1, transistor T2, transistor T3; wherein the base of transistor T1 and the base and collector of transistor T2, resistor R2, capacitor C p The emitter of transistor T1 is connected to resistor R4; the collector of transistor T1 is connected to resistor R3; the other end of resistor R4 is connected to terminal 1 of the dynamic linearization bias circuit; capacitor C p The other end of the resistor R2 is connected to the emitter of the transistor T3 and grounded; the base and collector of the transistor T3 are connected to the emitter of the transistor T2; the other end of the resistor R2 is connected to the 2nd end of the dynamic linearization bias circuit; the other end of the resistor R3 is connected to the 3rd end of the dynamic linearization bias circuit; as the RF power increases, a small part of the RF power will leak into the bias circuit, and after passing through the transistor T1, it will be connected to the linear capacitor C p Bypass to ground, therefore, the base potential Vb1 of T1 will remain unchanged. The leaked power increases the DC current of transistor T1, and the DC rectification of transistor T1 reduces the DC component Vbe1 of the base-emitter junction voltage. Since the potential Vb1 remains unchanged, the emitter potential of T1, i.e., the potential Ve1 of terminal 1 of the dynamic linearization bias circuit, is raised, thereby compensating for the problem of the potential reduction of terminal 1 of the bias circuit caused by the increase of RF power; at the same time, resistor R4 can suppress the instability of the bias circuit caused by the self-heating effect; the dynamic linearization bias circuit improves the overall linearity of the power amplifier and improves the amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier.

[0054] Fig.10 The power detection circuit schematic diagram of the present invention includes a capacitor C 17 , capacitor C 18 、Diode D p , resistor R5, resistor R6; capacitor C 17 Connected to terminal 1 of the power detection circuit; capacitor C 17 The other end is connected to the diode D p Connected to diode D p Connect the other end to the capacitor C 18 , resistor R5 is connected; capacitor C 18 The other end is grounded; the other end of resistor R5 is connected to one end of resistor R6 and two ends of the power amplifier circuit; the other end of resistor R6 is grounded. 17 The RF signal is coupled to the power detection circuit; due to the diode D p Due to the nonlinear resistance effect, the diode output current will have the nth harmonic current of the RF signal; through the capacitor C 18The high frequency components are filtered out, and the resistors R5 and R6 are used as loads, and a DC voltage that is positively correlated with the output power is output at two ends of the power detection circuit.

[0055] Fig.11 This is an S parameter simulation diagram of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; within the operating frequency band of 5-6GHz, the gain S21 parameter of the power amplifier is about 34dB, and the gain variation value is less than 0.5dB, reflecting the large gain provided by the three-stage amplification unit and the good gain flatness of the power amplifier provided by the negative feedback network; the S11 and S22 parameters of the power amplifier are both less than -10dB, reflecting the extremely low input and output reflection losses of the power amplifier.

[0056] Fig.12 The present invention provides simulated amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) distortion diagrams of a high-linearity and high-power GaAs HBT power amplifier with power detection. Compared with a case without a dynamic linearization bias circuit, the dynamic linearization bias circuit improves the linearity deterioration and current instability problems caused by the self-heating effect under high-power input of the GaAs HBT transistor by providing a bias voltage that changes dynamically with the input power, thereby improving the amplitude-amplitude distortion and amplitude-phase distortion of the power amplifier. Simulation results show that when the input power is -0.5dBm, the dynamic linearization bias circuit improves the amplitude distortion of the power amplifier from 0.57 to 0.64, and the phase distortion from 1.97dB to 1.20dB.

[0057] Fig.13 It is a simulation diagram of the second harmonic power of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; compared with the case without harmonic suppression, the output matching circuit with harmonic suppression short-circuits and opens the second harmonic respectively through the series resonance and parallel resonance of the inductor and capacitor, thereby greatly reducing the second harmonic power at the output end and improving the overall linearity of the power amplifier; the simulation results show that when the output power is 33dBm, the harmonic suppression reduces the output second harmonic power of the power amplifier from -8.75dBm to -26.11dBm.

[0058] Fig.14 The power detection voltage of the power detection circuit of the present invention varies with the simulation diagram of the output power; the capacitor C17 couples the radio frequency signal to the power detection circuit. Due to the nonlinear resistance of the diode Dp, the diode output current will have the nth harmonic current of the radio frequency signal. The capacitor C18 is introduced to form a low-pass filter. After filtering out the high-frequency component, the remaining DC voltage is proportional to the power of the radio frequency signal, and the power of the radio frequency signal can be detected.

[0059] Fig.15 It is a simulation diagram of input power (Pin)-output power (Pout) of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; the simulation results are consistent at different frequencies, reflecting the consistency of the performance of the power amplifier in the working frequency band of 5-6GHz; the output power 1dB compression point is between 32-33dBm, reflecting the high linearity of the power amplifier.

[0060] Fig.16 This is a simulation diagram of the output power (Pout)-power added efficiency (PAE) of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; the simulation results are consistent at different frequencies, reflecting the consistency of the performance of the power amplifier in the operating frequency band of 5-6GHz; the maximum value of the power added efficiency is about 37%, reflecting the high efficiency of the power amplifier.

[0061] Fig.17 The figure is a simulation diagram of the output power 1dB compression point of the high-linearity and high-power GaAs HBT power amplifier with power detection of the present invention; within the working frequency band of 5-6GHz, the output power 1dB compression point is maintained above 32dBm, reflecting the significant effect of the harmonic suppression effect of the output matching circuit and the dynamic linearization bias circuit on improving the linearity of the power amplifier;

[0062] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A high linearity and high power GaAs HBT power amplifier with power detection, characterized in that: The GaAs HBT power amplifier includes a radio frequency path, a bias module and a power detection circuit; The radio frequency path includes an input matching circuit, a first amplifying unit, a first interstage matching circuit, a second amplifying unit, a second interstage matching circuit, a third amplifying unit, an output matching circuit, a first negative feedback network, a second negative feedback network and an electrostatic protection circuit which are connected in sequence; the input matching circuit, the first amplifying unit, the first interstage matching circuit, the second amplifying unit, the second interstage matching circuit, the third amplifying unit and the output matching circuit are connected in sequence, the first negative feedback network is connected in parallel to the first amplifying unit, and the second negative feedback network is connected in parallel to the second amplifying unit; the radio frequency path is used to power amplify the input radio frequency signal; the electrostatic protection circuit is respectively connected to the first interstage matching circuit, the second interstage matching circuit and the output matching circuit to construct an electrostatic release path; The bias module includes a first dynamic linearization bias circuit, a second dynamic linearization bias circuit and a third dynamic linearization bias circuit; two input ends of the first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit are respectively connected to a DC voltage Vref and a DC voltage Vbatt, and output ends of the first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit are respectively connected to input ends of a first amplification unit, a second amplification unit and a third amplification unit, so as to provide a bias voltage that changes dynamically with input power for the first amplification unit, the second amplification unit and the third amplification unit; The power detection circuit is connected to the output end of the third amplifying unit and is used to output a DC voltage that is positively correlated with the output power.

2. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The first amplifying unit, the second amplifying unit and the third amplifying unit have the same structure, and each amplifying unit includes n-stage parallel transistors [Q1, Q2, ... Q n ]; The transistor triode is a GaAs HBT crystal triode; the size of each transistor triode and the number n of GaAs HBT transistors connected in parallel are selected according to the power requirements set by each level of amplifier.

3. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The first negative feedback network and the second negative feedback network have the same structure; each negative feedback network includes a first resistor R connected in sequence F , feedback inductor L F and the first capacitor C F ; The first resistor R F Keep away from feedback inductor L F One end of the first capacitor C is connected to the input end of the corresponding amplification unit. F Keep away from feedback inductor L F One end of is connected to the output end of the corresponding amplifying unit.

4. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The input matching circuit includes a first inductor L1, a second inductor L2, a second capacitor C2 and a third capacitor C3; wherein two ends of the second capacitor C2 are respectively connected to the input end and the output end of the input matching circuit; a first end of the first inductor L1 is connected to the input end of the input matching circuit, and a second end is grounded; a first end of the third capacitor C3 is connected to the output end of the input matching circuit, and a second end is grounded through the second inductor L2.

5. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The first inter-stage matching circuit includes a third inductor L3, a fourth inductor L4, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6; wherein the first end of the third inductor L3 and the first end of the fourth capacitor C4 are connected to the input end of the first inter-stage matching circuit; the second end of the third inductor L3 is connected to the first end of the fifth capacitor C5 and the power supply end of the first inter-stage matching circuit; the second end of the fifth capacitor C5 is grounded; the second end of the fourth capacitor C4 is connected to the first end of the fourth inductor L4 and the first end of the sixth capacitor C6; the second end of the fourth inductor L4 is grounded; and the second end of the sixth capacitor C6 is connected to the output end of the first inter-stage matching circuit.

6. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The second inter-stage matching circuit includes a fifth inductor L5, a sixth inductor L6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9 and a tenth capacitor C 10 ; wherein the first end of the fifth inductor L5 and the first end of the seventh capacitor C7 are connected to the input end of the second inter-stage matching circuit; the second end of the fifth inductor L5 is connected to the first end of the eighth capacitor C8 and the power supply end of the second inter-stage matching circuit; the second end of the eighth capacitor C8 is grounded; the second end of the seventh capacitor C7 is connected to the first end of the ninth capacitor C9, the first end of the sixth inductor L6, and the tenth capacitor C 10 The first end of the ninth capacitor C9 is connected to the ground; the second end of the sixth inductor L6 is grounded; the tenth capacitor C 10 The second end of is connected to the output end of the second inter-stage matching circuit.

7. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The output matching circuit includes a seventh inductor L7, an eighth inductor L8, a ninth inductor L9, a tenth inductor L 10 11th inductor L 11 , 12th inductor L 12 、11th capacitor C 11 , the twelfth capacitor C 12 、Thirteenth capacitor C 13 , Fourteenth capacitor C 14 、15th capacitor C 15 and the sixteenth capacitor C 16 ; The eleventh capacitor C 11 The first end of the twelfth capacitor C 12 The first end of the ninth inductor L9, the first end of the twelfth inductor L 12 The first end of is connected to the input end of the output matching circuit; the eleventh capacitor C 11 The second end of the twelfth capacitor C is connected to the first end of the seventh inductor L7; the second end of the seventh inductor L7 is grounded; 12 The second end of the twelfth inductor L is connected to the first end of the eighth inductor L8; the second end of the eighth inductor L8 is grounded; 12 The second end and the sixteenth capacitor C 16 The first end of the output matching circuit is connected to the power supply end; the sixteenth capacitor C 16 The second end of the ninth inductor L9 is connected to the thirteenth capacitor C 13 The first end of the fourteenth capacitor C 14 The first end of the thirteenth capacitor C 13 The second end of the fourteenth capacitor C is grounded; 14 The second end and the tenth inductor L 10 The first end of the eleventh inductor L 11 The first end of the fifteenth capacitor C 15 The first end of the tenth inductor L 10 The second end of the eleventh inductor L is grounded; 11 The second end of the fifteenth capacitor C 15 The second end of the output is connected to the output end of the output matching circuit.

8. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The electrostatic protection circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6; wherein the first diode D1, the second diode D2, the third diode D3, the fourth diode D4 and the fifth diode D5 are forward biased and connected in series, the anode of the first diode D1 is connected to the electrostatic discharge end of the electrostatic protection circuit, and the cathode of the fifth diode D5 is grounded; the sixth diode D6 is reverse biased, the anode of the sixth diode D6 is connected to the electrostatic discharge end of the electrostatic protection circuit, and the cathode is grounded.

9. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The first dynamic linearization bias circuit, the second dynamic linearization bias circuit and the third dynamic linearization bias circuit have the same structure; Each dynamic linearization bias circuit includes a second resistor R2, a third resistor R3, a fourth resistor R4, a sixteenth capacitor C p , a first transistor T1, a second transistor T2 and a third transistor T3; wherein the base of the first transistor T1 is respectively connected to the base and collector of the second transistor T2, the first end of the second resistor R2, the sixteenth capacitor C p The emitter of the first transistor T1 is connected to the first end of the fourth resistor R4; the collector of the first transistor T1 is connected to the first end of the third resistor R3; the second end of the fourth resistor R4 is connected to the output end of the dynamic linearization bias circuit; the sixteenth capacitor C p The second end of the third transistor T3 is connected to the emitter of the third transistor T3 and is grounded; the base and collector of the third transistor T3 are connected to the emitter of the second transistor T2; the second end of the second resistor R2 is connected to the first input end of the dynamic linearization bias circuit; the second end of the third resistor R3 is connected to the second input end of the dynamic linearization bias circuit; the first input end of the dynamic linearization bias circuit is connected to the power supply terminal V ref The second input terminal of the dynamic linearization bias circuit is connected to the power supply terminal V batt .

10. The high linearity and high power GaAs HBT power amplifier with power detection according to claim 1, characterized in that: The power detection circuit includes a seventeenth capacitor C 17 , the eighteenth capacitor C 18 , the seventh diode D p , a fifth resistor R5 and a sixth resistor R6; wherein a seventeenth capacitor C 17 The first end of is connected to the voltage detection input end of the power detection circuit; the seventeenth capacitor C 17 The second end of the seventh diode D p The anode of the seventh diode D p The negative electrode and the eighteenth capacitor C 18 The first end of the eighth capacitor C is connected to the first end of the fifth resistor R5; 18 The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the voltage detection output end of the power amplifier circuit respectively; the second end of the sixth resistor R6 is grounded.

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