High linearity power amplifier based on adjustable supersaturation preamplifier tube and its design method

Abstract

The present invention provides a high linearity power amplifier based on an adjustable supersaturation preamplifier tube and a design method, wherein the high linearity power amplifier comprises a power division module, a main power amplifier module, a phase shift module, a nonlinear signal generation module, a phase compensation module, an auxiliary power amplifier module and an impedance conversion module. The entire power amplifier is divided into two branches, and the input initial radio frequency signal is divided into two paths. In the first branch, the radio frequency signal component is amplified and phase adjusted in sequence to obtain a first intermediate radio frequency signal. In the second branch, the radio frequency signal component acts on the adjustable supersaturation preamplifier tube to generate a third-order intermodulation nonlinear signal. After the third-order intermodulation nonlinear signal is phase compensated and amplified in sequence, a second intermediate radio frequency signal is obtained. Subsequently, the output signals of the two branches are superimposed and combined, so that the third-order intermodulation components of the second intermediate radio frequency signal and the first intermediate radio frequency signal cancel each other, thereby improving the linearity of the power amplifier.

Description

Technical Field

[0001] The invention relates to the field of microwave technology, and in particular to a high-linearity power amplifier based on an adjustable supersaturation preamplifier tube and a design method thereof. Background Art

[0002] The maturity of wireless communication technology has brought about the broadband and diversified development of wireless services. The base station structure is constantly evolving. The power amplifier is the device with the largest energy consumption and the highest nonlinearity in the base station. Its performance directly affects the transmission distance and signal quality of the RF signal. In order to save energy, the power amplifier in the base station should have both high output efficiency and high linearity indicators. The Doherty power amplifier can maintain high efficiency within a large power back-off range, taking into account both efficiency and linearity indicators, but its linearity still needs to be improved.

[0003] At present, the improvement of the linearity of power amplifiers is generally based on the following two perspectives: on the one hand, from the perspective of process, high-linearity materials such as GaN and GaAs are used; on the other hand, from the perspective of circuit design, feedforward technology, negative feedback technology, pre-distortion technology, etc. are used to improve linearity. In recent years, various linearization technologies and efficiency improvement technologies have shown a trend of integration. For example, the integration of pre-distortion technology into Doherty power amplifiers can improve linearity while maintaining high efficiency of the power amplifier. This is also in line with the trend of future development of power amplifiers towards high linearity, high efficiency and small size. However, even if various linearization technologies are integrated together, the improvement of the linearity of the power amplifier is still limited, and the corresponding power amplifier has a complex structure and high cost.

[0004] Therefore, there is an urgent need for a power amplifier technology solution with a simple structure and high linearity. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a technical solution for a power amplifier based on field effect transistors to achieve third-order intermodulation component compensation, so as to solve the above-mentioned technical problems.

[0006] To achieve the above-mentioned purpose and other related purposes, the technical solution provided by the present invention is as follows.

[0007] A high linearity power amplifier based on an adjustable supersaturation preamplifier tube, comprising:

[0008] A power division module, whose input end serves as the input end of the high linearity power amplifier and whose input end is connected to the initial radio frequency signal;

[0009] A main power amplifier module, whose input end is connected to the first output end of the power division module;

[0010] A phase shift module, whose input end is connected to the output end of the main power amplifier module;

[0011] A nonlinear signal generating module, whose input end is connected to the second output end of the power dividing module;

[0012] A phase compensation module, whose input end is connected to the output end of the nonlinear signal generating module;

[0013] An auxiliary power amplifier module, whose input end is connected to the output end of the phase compensation module;

[0014] An impedance transformation module, whose input end is respectively connected to the output end of the phase shift module and the output end of the auxiliary power amplifier module, whose output end serves as the output end of the high linearity power amplifier, and whose output end outputs the target radio frequency signal;

[0015] Wherein, the nonlinear signal generating module comprises an adjustable oversaturation field effect transistor, the gate of the adjustable oversaturation field effect transistor is connected to the second output end of the power division module, the drain of the adjustable oversaturation field effect transistor generates a third-order intermodulation nonlinear signal, and the third-order intermodulation nonlinear signal is successively subjected to the phase compensation processing of the phase compensation module and the amplification processing of the auxiliary power amplifier module, and then offsets the third-order intermodulation component of the signal output by the main power amplifier module and subjected to the phase adjustment processing of the phase shift module.

[0016] Optionally, the power division module comprises an unequally divided Wilkinson power division module.

[0017] Optionally, the power division module, the main power amplifier module, the phase shift module, the nonlinear signal generation module, the phase compensation module, the auxiliary power amplifier module, and the impedance transformation module all use a Rogers 4350 dielectric substrate with a thickness of 0.508 mm and a dielectric constant of 3.48.

[0018] Optionally, the main power amplifier module includes a power amplifier tube based on LDMOS technology, and the auxiliary power amplifier module includes a power amplifier tube based on LDMOS technology.

[0019] Optionally, the adjustable oversaturation field effect transistor includes an N-channel high electron mobility transistor, and the nonlinear signal generating module also includes a bias unit, the bias unit includes a first microstrip transmission line, a second microstrip transmission line, a first filter capacitor, a second filter capacitor, a third filter capacitor, a fourth filter capacitor, a fifth filter capacitor and a sixth filter capacitor, the gate of the N-channel high electron mobility transistor is connected to the second output end of the power division module via the first microstrip transmission line connected in series, one end of the first filter capacitor is connected to the first microstrip transmission line and the other end is grounded, the second filter capacitor and the third filter capacitor are respectively connected in parallel with the first filter capacitor, the source of the N-channel high electron mobility transistor is grounded, the drain of the N-channel high electron mobility transistor is connected to the input end of the phase compensation module via the second microstrip transmission line connected in series, one end of the fourth filter capacitor is connected to the second microstrip transmission line and the other end is grounded, and the fifth filter capacitor and the sixth filter capacitor are respectively connected in parallel with the fourth filter capacitor.

[0020] Optionally, the width of the first microstrip transmission line is smaller than the width of the second microstrip transmission line, and the length of the first microstrip transmission line is smaller than the length of the second microstrip transmission line.

[0021] Optionally, the capacitance value of the first filter capacitor is equal to the capacitance value of the fourth filter capacitor, the capacitance value of the second filter capacitor is equal to the capacitance value of the fifth filter capacitor, and the capacitance value of the third filter capacitor is equal to the capacitance value of the sixth filter capacitor.

[0022] Optionally, the capacitance value of the first filter capacitor is 10 pf, the capacitance value of the second filter capacitor is 100 pf, and the capacitance value of the third filter capacitor is 1000 pf.

[0023] A high linearity power amplifier design method based on an adjustable supersaturation preamplifier tube, comprising:

[0024] A two-branch power amplifier structure is designed, which includes a power division module, a main power amplifier module, a phase shift module, a phase compensation module, an auxiliary power amplifier module and an impedance transformation module. The first output end of the power division module is connected to the first input end of the impedance transformation module via the main power amplifier module and the phase shift module connected in series in sequence, forming a first branch. The second output end of the power division module is connected to the second input end of the impedance transformation module via the phase compensation module and the auxiliary power amplifier module connected in series in sequence, forming a second branch.

[0025] In the second branch, a nonlinear signal generating module is serially connected between the second output end of the power dividing module and the input end of the phase compensation module, and the input radio frequency signal is acted on the nonlinear signal generating module after being processed by the power dividing module, and a third-order intermodulation nonlinear signal is generated by the nonlinear signal generating module. The third-order intermodulation nonlinear signal is sequentially processed by the phase compensation module and the amplification module of the auxiliary power amplifier module, and then the third-order intermodulation component of the signal output by the main power amplifier module and processed by the phase adjustment module is offset against each other;

[0026] Wherein, the nonlinear signal generating module comprises an adjustable oversaturation field effect transistor, and the third-order intermodulation nonlinear signal is generated by the adjustable oversaturation field effect transistor in front of the second branch.

[0027] As described above, the high linearity power amplifier and design method based on the adjustable supersaturation pre-amplifier tube provided by the present invention have at least the following beneficial effects:

[0028] The power amplifier structure is divided into two branches, and the input initial RF signal is divided into two paths. The first RF signal component is sequentially amplified by the main power amplifier module and phase adjusted by the phase shift module to obtain a first intermediate RF signal. The second RF signal component acts on the field effect transistor in the nonlinear signal generation module to generate a third-order intermodulation nonlinear signal. The third-order intermodulation nonlinear signal is sequentially phase compensated by the phase compensation module and amplified by the auxiliary power amplifier module to obtain a second intermediate RF signal. The amplitude of the second intermediate RF signal is equal to the amplitude of the third-order intermodulation component of the first intermediate RF signal, and the phase of the second intermediate RF signal is opposite to the phase of the third-order intermodulation component of the first intermediate RF signal. Subsequently, the output signals of the two branches are superimposed and combined, so that the third-order intermodulation components of the second intermediate RF signal and the first intermediate RF signal cancel each other, and a target RF signal with high linearity is obtained, which effectively improves the linearity of the power amplifier. The structure is simple, no other complex control circuits are required, the volume is small, and it is easy to integrate with other microwave circuits, and it has strong practicality and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the high linearity power amplifier in the present invention.

[0030] Figure 2 for Figure 1 Schematic diagram of the structure of the nonlinear signal generating module 4. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0032] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0033] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] As mentioned in the background technology above, when studying the linearity problem of power amplifiers, the inventors found that the current process means or circuit design means are used to improve the linearity of power amplifiers, but the degree of linearity improvement is limited, and the corresponding power amplifiers have complex structural principles and high costs; this is mainly because the nonlinear influencing factors are not corrected or eliminated from the root.

[0035] Based on this, the present invention proposes a technical solution for improving the linearity of a power amplifier: since the third-order intermodulation component is the main factor affecting the linearity of the radio frequency signal, the present invention designs two branches and divides the input initial radio frequency signal into a first radio frequency signal and a second radio frequency signal, performs power amplification processing on the first radio frequency signal through one branch to obtain a first intermediate radio frequency signal, generates a third-order intermodulation nonlinear signal based on the second radio frequency signal through another branch, performs phase compensation adjustment and power amplification processing on the third-order intermodulation nonlinear signal to obtain a second intermediate radio frequency signal that is an anti-phase signal to the third-order intermodulation component of the first radio frequency signal, and finally combines the outputs of the two branches to cancel out the third-order intermodulation components of the second intermediate radio frequency signal and the first intermediate radio frequency signal to obtain a target radio frequency signal with high linearity.

[0036] First, if Figure 1 As shown, the present invention provides a high linearity power amplifier based on an adjustable supersaturation preamplifier tube, which comprises:

[0037] The power division module 1 has an input end serving as an input end of a high linearity power amplifier, and its input end is connected to an initial radio frequency signal V0;

[0038] A main power amplifier module 2, whose input terminal is connected to the first output terminal of the power divider module 1;

[0039] A phase shift module 3, whose input end is connected to the output end of the main power amplifier module 2;

[0040] A nonlinear signal generating module 4, whose input end is connected to the second output end of the power dividing module 1;

[0041] A phase compensation module 5, whose input end is connected to the output end of the nonlinear signal generating module 4;

[0042] An auxiliary power amplifier module 6, whose input terminal is connected to the output terminal of the phase compensation module 5;

[0043] The impedance transformation module 7, whose input end is respectively connected to the output end of the phase shift module 3 and the output end of the auxiliary power amplifier module 6, and whose output end serves as the output end of the high linearity power amplifier, outputs the target radio frequency signal V1;

[0044] Among them, the nonlinear signal generating module 4 includes an adjustable oversaturated field effect transistor, the gate of the adjustable oversaturated field effect transistor is connected to the second output end of the power division module 1, and the drain of the adjustable oversaturated field effect transistor generates a third-order intermodulation nonlinear signal V04. After the third-order intermodulation nonlinear signal V04 is successively processed by the phase compensation module 5 and the amplification processing of the auxiliary power amplifier module 6, it offsets the third-order intermodulation component of the signal output by the main power amplifier module 2 and processed by the phase adjustment of the phase shift module 3.

[0045] In detail, Figure 1 As shown, the power division module 1 includes an unequally divided Wilkinson power division module. The power division module 1 includes a dielectric substrate, a transmission line and a resistor. The transmission line and the resistor are arranged on the dielectric substrate. The power division module 1 has an input end and two output ends. The power division module 1 divides the initial RF signal V0 into a first RF signal V01 and a second RF signal V02.

[0046] In detail, Figure 1 As shown, the main power amplifier module 2 performs power amplification on the first RF signal V01, and the auxiliary power amplifier module 6 performs power amplification on the RF signal output by the phase compensation module 5 to obtain a second intermediate RF signal V05; the main power amplifier module 2 may include a power amplifier tube based on the LDMOS process, and the auxiliary power amplifier module 6 may also include a power amplifier tube based on the LDMOS process. For example, the LDMOS process transistor of the MRF8P26080 model manufactured by Freescale may be used, which is not limited here.

[0047] In detail, the phase shift module 3 and the phase compensation module 5 are mainly used to compensate and adjust the phase of the input RF signal. The phase shift module 3 performs a phase shift operation on the output signal of the main power amplifier module 2 to obtain a first intermediate RF signal V03. The phase compensation module 5 performs a phase shift operation on the third-order intermodulation nonlinear signal V04 generated by the nonlinear signal generation module 4, and transmits the phase shift operation to the auxiliary power amplifier module 6. The phase shift module 3 and the phase compensation module 5 can adopt an analog phase shift circuit based on a conventional RC or LC structure, or a digital phase shifter designed based on a standard logic device, which is not limited here.

[0048] In detail, the nonlinear signal generating module 4 is mainly used to generate a third-order intermodulation nonlinear signal, which is connected to the second RF signal V02 and generates a third-order intermodulation nonlinear signal V04 according to the second RF signal V02.

[0049] In more detail, Figure 2As shown, the adjustable supersaturation field effect transistor includes an N-channel high electron mobility transistor Q1, and the nonlinear signal generating module 4 also includes a bias unit, which includes a first microstrip transmission line D1, a second microstrip transmission line D2, a first filter capacitor C1, a second filter capacitor C2, a third filter capacitor C3, a fourth filter capacitor C4, a fifth filter capacitor C5 and a sixth filter capacitor C6. The gate of the N-channel high electron mobility transistor Q1 is connected to the second output end of the power division module 1 (i.e., connected to the second RF signal V02) via the first microstrip transmission line D1 connected in series, and the first filter capacitor One end of C1 is connected to the first microstrip transmission line D1, and the other end is grounded. The second filter capacitor C2 and the third filter capacitor C3 are respectively connected in parallel with the first filter capacitor C1. The source of the N-channel high electron mobility transistor Q1 is grounded. The drain of the N-channel high electron mobility transistor Q1 is connected to the input end of the phase compensation module 5 (i.e., outputs the third-order intermodulation nonlinear signal V04) via the second microstrip transmission line D2 connected in series. One end of the fourth filter capacitor C4 is connected to the second microstrip transmission line D2, and the other end is grounded. The fifth filter capacitor C5 and the sixth filter capacitor C6 are respectively connected in parallel with the fourth filter capacitor C4.

[0050] The N-channel high electron mobility transistor Q1 may be a CGH40010 GaN process HEMT produced by CREE, which is not limited here. The width W of the first microstrip transmission line D1 is D1 Smaller than the width W of the second microstrip transmission line D2 D2 , the length L of the first microstrip transmission line D1 D1 is smaller than the length L of the second microstrip transmission line D2 D2 The capacitance value of the first filter capacitor C1 is equal to the capacitance value of the fourth filter capacitor C4, the capacitance value of the second filter capacitor C2 is equal to the capacitance value of the fifth filter capacitor C5, and the capacitance value of the third filter capacitor C3 is equal to the capacitance value of the sixth filter capacitor C6.

[0051] In an optional embodiment of the present invention, the width W of the first microstrip transmission line D1 is D1 is 0.67 mm, and the length L of the first microstrip transmission line D1 is D1 The width W of the second microstrip transmission line D2 is 16.8 mm. D2 is 1.24 mm, and the length L of the second microstrip transmission line D2 is D2 is 17.9mm; the capacitance value of the first filter capacitor C1 is 10pf, the capacitance value of the second filter capacitor C2 is 100pf, and the capacitance value of the third filter capacitor C3 is 1000pf.

[0052] In more detail, Figure 2As shown, the gate of the N-channel high electron mobility transistor Q1 is connected to the second RF signal V02. Under the control of the second RF signal V02, a third-order intermodulation nonlinear signal V04 can be generated at its drain. The amplitude and phase of the third-order intermodulation nonlinear signal V04 can be adjusted by adjusting the size of the second RF signal V02. After the phase is finely adjusted by the phase compensation module 5 and amplified by the auxiliary power amplifier module 6, a second intermediate RF signal V05 is obtained. After the first RF signal V01 is amplified by the main power amplifier module 2 and the phase is finely adjusted by the phase shift module 3, a first intermediate RF signal V03 is obtained. By setting and adjusting the parameters of the power division module 1, the N-channel high electron mobility transistor Q1, the phase shift module 3 and the phase compensation module 5, the second intermediate RF signal V05 can just cancel the third-order intermodulation component of the first intermediate RF signal V03, and the target RF signal V1 with higher linearity is output after superposition.

[0053] Among them, with respect to the linear distortion of the output signal of the first RF signal V01 (main power amplifier), the output of the third-order intermodulation nonlinear signal V04 is affected by tuning the supply voltage and matching circuit of the front field effect transistor of the second RF signal V02 (auxiliary power amplifier), thereby flexibly adjusting the linearity of the entire Doherty power amplifier.

[0054] It should be noted that adjustable supersaturation field effect transistors are not limited to Figure 2 The N-channel high electron mobility transistor shown may also be a field effect transistor of other structures, as long as it can generate a third-order intermodulation nonlinear signal at the drain under the control of the second RF signal V02 at the gate, and the present invention is not limited to this.

[0055] In detail, the impedance transformation module 7 provides an adjustable output impedance, and the target radio frequency signal V1 is output externally after passing through the impedance transformation module 7. The impedance transformation module 7 can be an adjustable impedance matching circuit based on an RLC network, which will not be described in detail here.

[0056] In detail, the power division module 1, the main power amplifier module 2, the phase shift module 3, the nonlinear signal generation module 4, the phase compensation module 5, the auxiliary power amplifier module 6, and the impedance transformation module 7 can all adopt a component integrated structure, such as a Rogers 4350 dielectric substrate with a thickness of 0.508 mm and a dielectric constant of 3.48 and various components for integrated design. The modules are independently integrated and manufactured, and each module includes a dielectric substrate and components arranged on the dielectric substrate. Finally, the modules are integrated and assembled to form a complete power amplifier.

[0057] Therefore, on the basis of effectively improving the linearity of the power amplifier, the entire power amplifier has a simple structure, does not require other complex control circuits, and has a highly integrated design. It is small in size and easy to integrate with other microwave circuits, and has strong practicality and application prospects.

[0058] Secondly, based on the same design concept as the above-mentioned high linearity power amplifier, the present invention also provides a high linearity power amplifier design method based on an adjustable supersaturation pre-amplifier tube, comprising the steps of:

[0059] S1. Design a two-branch power amplifier structure, which includes a power division module, a main power amplifier module, a phase shift module, a phase compensation module, an auxiliary power amplifier module and an impedance transformation module. The first output end of the power division module is connected to the first input end of the impedance transformation module via the main power amplifier module and the phase shift module connected in series in sequence, forming a first branch. The second output end of the power division module is connected to the second input end of the impedance transformation module via the phase compensation module and the auxiliary power amplifier module connected in series in sequence, forming a second branch.

[0060] S2, in the second branch, a nonlinear signal generating module is serially connected between the second output end of the power division module and the input end of the phase compensation module, the input RF signal is processed by the power division module and acts on the nonlinear signal generating module, and a third-order intermodulation nonlinear signal is generated by the nonlinear signal generating module, and the third-order intermodulation nonlinear signal is successively processed by the phase compensation of the phase compensation module and the amplification of the auxiliary power amplifier module, and then the third-order intermodulation component of the signal output by the main power amplifier module and processed by the phase adjustment of the phase shift module is offset against each other;

[0061] The nonlinear signal generation module includes an adjustable oversaturation field effect transistor, and generates a third-order intermodulation nonlinear signal through the adjustable oversaturation field effect transistor in the front of the second branch.

[0062] In an optional embodiment of the present invention, the adjustable oversaturation field effect transistor includes an adjustable oversaturation N-channel field effect transistor; the source of the adjustable oversaturation N-channel field effect transistor is grounded, and the gate of the adjustable oversaturation N-channel field effect transistor is connected to a second radio frequency signal, and the third-order intermodulation nonlinear signal is generated at the drain of the adjustable oversaturation N-channel field effect transistor by utilizing the characteristics of the adjustable oversaturation N-channel field effect transistor.

[0063] In the above-mentioned high-linearity power amplifier design method based on an adjustable supersaturation pre-power amplifier tube, the power amplifier structure first divides the input initial RF signal into a first RF signal and a second RF signal, then performs power amplification and phase adjustment processing on the first RF signal through the first branch to obtain a first intermediate RF signal, and then generates a third-order intermodulation nonlinear signal based on the second RF signal based on the adjustable supersaturation pre-power amplifier tube in the second branch, and performs phase compensation adjustment and power amplification processing on the third-order intermodulation nonlinear signal based on the second branch to obtain a second intermediate RF signal that is an anti-phase signal with the third-order intermodulation component of the first RF signal, and finally combines the two signals at the impedance conversion module to cancel the third-order intermodulation components of the second intermediate RF signal and the first intermediate RF signal to obtain a target RF signal with high linearity, thereby effectively improving the linearity of the power amplifier.

[0064] Among them, in view of the linear distortion of the output signal of the first RF signal (main power amplifier), the output of the third-order intermodulation nonlinear signal can be affected by tuning the supply voltage and matching circuit of the front field effect transistor (that is, the adjustable oversaturation N-channel field effect transistor) of the second RF signal (auxiliary power amplifier), so as to flexibly adjust the linearity of the entire Doherty power amplifier.

[0065] In summary, in the high linearity power amplifier and design method based on adjustable supersaturation preamplifier tube provided by the present invention, the entire power amplifier structure is divided into two branches, and the input initial RF signal is divided into two paths. In the first branch, the first RF signal component is sequentially subjected to power amplification processing of the main power amplifier module and phase adjustment processing of the phase shift module to obtain a first intermediate RF signal. In the second branch, the second RF signal component acts on the field effect transistor in the nonlinear signal generation module to generate a third-order intermodulation nonlinear signal. The third-order intermodulation nonlinear signal is sequentially subjected to phase compensation processing of the phase compensation module, amplification processing of the auxiliary power amplifier module, and the like. After the large processing, a second intermediate RF signal is obtained, the amplitude of the second intermediate RF signal is equal to the amplitude of the third-order intermodulation component of the first intermediate RF signal, and the phase of the second intermediate RF signal is opposite to the phase of the third-order intermodulation component of the first intermediate RF signal. Subsequently, the output signals of the two branches are superimposed and combined, so that the third-order intermodulation components of the second intermediate RF signal and the first intermediate RF signal cancel each other out, and a target RF signal with high linearity is obtained, which effectively improves the linearity of the power amplifier, and has a simple structure, no need for other complex control circuits, small size, and is easy to integrate with other microwave circuits, and has strong practicality and application prospects.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A high linearity power amplifier based on an adjustable supersaturation preamplifier tube, characterized in that: include: A power division module, whose input end serves as the input end of the high linearity power amplifier and whose input end is connected to the initial radio frequency signal; A main power amplifier module, whose input end is connected to the first output end of the power division module; A phase shift module, whose input end is connected to the output end of the main power amplifier module; A nonlinear signal generating module, whose input end is connected to the second output end of the power dividing module; A phase compensation module, whose input end is connected to the output end of the nonlinear signal generating module; An auxiliary power amplifier module, whose input end is connected to the output end of the phase compensation module; An impedance transformation module, whose input end is respectively connected to the output end of the phase shift module and the output end of the auxiliary power amplifier module, whose output end serves as the output end of the high linearity power amplifier, and whose output end outputs the target radio frequency signal; Wherein, the nonlinear signal generating module comprises an adjustable oversaturation field effect transistor, the gate of the adjustable oversaturation field effect transistor is connected to the second output terminal of the power division module, the drain of the adjustable oversaturation field effect transistor generates a third-order intermodulation nonlinear signal, and the third-order intermodulation nonlinear signal is successively subjected to the phase compensation processing of the phase compensation module and the amplification processing of the auxiliary power amplifier module, and then the third-order intermodulation component of the signal output by the main power amplifier module and subjected to the phase adjustment processing of the phase shift module is offset against each other; Wherein, the adjustable oversaturation field effect transistor includes an N-channel high electron mobility transistor, the nonlinear signal generating module also includes a bias unit, the bias unit includes a first microstrip transmission line, a second microstrip transmission line, a first filter capacitor, a second filter capacitor, a third filter capacitor, a fourth filter capacitor, a fifth filter capacitor and a sixth filter capacitor, the gate of the N-channel high electron mobility transistor is connected to the second output end of the power division module via the first microstrip transmission line connected in series, one end of the first filter capacitor is connected to the first microstrip transmission line and the other end is grounded, the second filter capacitor and the third filter capacitor are respectively connected in parallel with the first filter capacitor, the source of the N-channel high electron mobility transistor is grounded, the drain of the N-channel high electron mobility transistor is connected to the input end of the phase compensation module via the second microstrip transmission line connected in series, one end of the fourth filter capacitor is connected to the second microstrip transmission line and the other end is grounded, the fifth filter capacitor and the sixth filter capacitor are respectively connected in parallel with the fourth filter capacitor.

2. The high linearity power amplifier based on an adjustable supersaturation preamplifier tube according to claim 1, characterized in that: The width of the first microstrip transmission line is smaller than the width of the second microstrip transmission line, and the length of the first microstrip transmission line is smaller than the length of the second microstrip transmission line.

3. The high linearity power amplifier based on an adjustable supersaturation preamplifier tube according to claim 1, characterized in that: The capacitance value of the first filter capacitor is equal to the capacitance value of the fourth filter capacitor, the capacitance value of the second filter capacitor is equal to the capacitance value of the fifth filter capacitor, and the capacitance value of the third filter capacitor is equal to the capacitance value of the sixth filter capacitor.

4. A high linearity power amplifier design method based on an adjustable supersaturation preamplifier tube, characterized in that: include: A two-branch power amplifier structure is designed, which includes a power division module, a main power amplifier module, a phase shift module, a phase compensation module, an auxiliary power amplifier module and an impedance transformation module. The first output end of the power division module is connected to the first input end of the impedance transformation module via the main power amplifier module and the phase shift module connected in series in sequence, forming a first branch. The second output end of the power division module is connected to the second input end of the impedance transformation module via the phase compensation module and the auxiliary power amplifier module connected in series in sequence, forming a second branch. In the second branch, a nonlinear signal generating module is serially connected between the second output end of the power dividing module and the input end of the phase compensation module, and the input radio frequency signal is acted on the nonlinear signal generating module after being processed by the power dividing module, and a third-order intermodulation nonlinear signal is generated by the nonlinear signal generating module. The third-order intermodulation nonlinear signal is sequentially processed by the phase compensation module and the amplification module of the auxiliary power amplifier module, and then the third-order intermodulation component of the signal output by the main power amplifier module and processed by the phase adjustment module is offset against each other; Wherein, the nonlinear signal generating module includes an adjustable oversaturation field effect transistor, and the third-order intermodulation nonlinear signal is generated by the adjustable oversaturation field effect transistor in the front of the second branch; Wherein, the adjustable oversaturation field effect transistor includes an N-channel high electron mobility transistor, the nonlinear signal generating module also includes a bias unit, the bias unit includes a first microstrip transmission line, a second microstrip transmission line, a first filter capacitor, a second filter capacitor, a third filter capacitor, a fourth filter capacitor, a fifth filter capacitor and a sixth filter capacitor, the gate of the N-channel high electron mobility transistor is connected to the second output end of the power division module via the first microstrip transmission line connected in series, one end of the first filter capacitor is connected to the first microstrip transmission line and the other end is grounded, the second filter capacitor and the third filter capacitor are respectively connected in parallel with the first filter capacitor, the source of the N-channel high electron mobility transistor is grounded, the drain of the N-channel high electron mobility transistor is connected to the input end of the phase compensation module via the second microstrip transmission line connected in series, one end of the fourth filter capacitor is connected to the second microstrip transmission line and the other end is grounded, the fifth filter capacitor and the sixth filter capacitor are respectively connected in parallel with the fourth filter capacitor.

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