Tree-structure-based gallium nitride amplitude limiting circuit and gallium nitride amplitude limiting chip

Abstract

The invention discloses a gallium nitride amplitude limiting circuit and a gallium nitride amplitude limiting chip based on a tree structure. The circuit comprises a first-stage amplitude limiting unit, a second-stage amplitude limiting unit and a third-stage amplitude limiting unit which are connected in sequence, wherein the first-stage amplitude limiting unit comprises two groups of first-stage geminate transistors and a tree-shaped structure, the tree-shaped structure is connected with the two groups of first-stage geminate transistors, and the two groups of first-stage geminate transistors are located at two sides of the tree-shaped structure, and according to the gallium nitride amplitude limiting circuit disclosed by the invention, the complexity of a circuit process can be reduced while the power resistance of the gallium nitride amplitude limiting circuit can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of microwave technology, and particularly relates to a gallium nitride limiting amplifier circuit based on a tree structure and a gallium nitride limiting amplifier chip. BACKGROUND

[0002] The limiting amplifier chip is a key protection device in a radio frequency / microwave system, is usually arranged at the front end of a receiving link, and is used for enabling an input low-power microwave signal to pass through with small loss and input high-power microwave signals to be attenuated to a low-power level, so as to prevent sensitive devices such as a low-noise amplifier and a mixer in a later stage from being burned out due to overload.

[0003] Although the existing limiting amplifier chip can meet the requirement of low insertion loss, the limiting amplifier circuit of the existing limiting amplifier chip mainly adopts a PIN diode of gallium arsenide material. Since the thermal conductivity of the gallium arsenide material is low, the continuous wave power processing capacity of the limiting amplifier circuit is limited, that is, the power tolerance of the limiting amplifier circuit is low, so that the limiting amplifier chip cannot meet the requirement of a continuous high-power scene. Meanwhile, the existing limiting amplifier circuit needs to be conducted through an inductor, and when the input signal is a high-power microwave signal, a power amplifier structure needs to be used to divide the high-power microwave signal into two paths for limiting, and after the power is reduced, the power amplifier structure is used to combine the high-power microwave signal into one path for secondary limiting. The circuit process is relatively complex.

[0004] Therefore, how to improve the power tolerance of the limiting amplifier circuit while reducing the complexity of the circuit process is a technical problem to be solved at present. SUMMARY

[0005] In order to solve the problem of how to improve the power tolerance of the limiting amplifier circuit while reducing the complexity of the circuit process, the application provides a gallium nitride limiting amplifier circuit based on a tree structure and a gallium nitride limiting amplifier chip. The technical problem to be solved by the application is solved through the following technical scheme. The application provides a gallium nitride limiting amplifier circuit based on a tree structure, which comprises a first-stage limiting unit, a second-stage limiting unit and a third-stage limiting unit connected in sequence. The first-stage limiting unit comprises two groups of first-stage pairs and a tree structure, the tree structure is connected to the two groups of first-stage pairs, and the two groups of first-stage pairs are located on the two sides of the tree structure.

[0006] In an embodiment of the application, the tree structure comprises a first tree structure and a second tree structure. The first end of the first tree structure is connected to the first group of first-stage pairs, the second end of the first tree structure is connected to the second end of the second tree structure, and the first end of the second tree structure is connected to the second group of first-stage pairs.

[0007] In one embodiment of the present application, the first tree structure and the second tree structure are identical.

[0008] In one embodiment of the present application, the first group of first-stage pairs of diodes includes the first diode to the eighth diode, the second group of first-stage pairs of diodes includes the ninth diode to the sixteenth diode, and the first ends of the first tree structure and the second tree structure each include a first branch and a second branch. In one embodiment of the present application, the first group of first-stage pairs of diodes includes the first diode to the eighth diode, the second group of first-stage pairs of diodes includes the ninth diode to the sixteenth diode, and the first ends of the first tree structure and the second tree structure each include a first branch and a second branch. In one embodiment of the present application, the first group of first-stage pairs of diodes includes the first diode to the eighth diode, the second group of first-stage pairs of diodes includes the ninth diode to the sixteenth diode, and the first ends of the first tree structure and the second tree structure each include a first branch and a second branch.

[0009] In one embodiment of the present application, the first-stage limiting unit, the second-stage limiting unit, and the third-stage limiting unit are connected through a microstrip line.

[0010] In one embodiment of the present application, the second-stage limiting unit includes a group of second-stage pairs of diodes, and the third-stage limiting unit includes a group of third-stage pairs of diodes.

[0011] In one embodiment of the present application, the microstrip line includes a two-stage matching microstrip, a three-stage matching microstrip, and an output matching microstrip line, the second-stage pairs of diodes include the seventeenth diode to the twenty-second diode, and the third-stage pairs of diodes include the twenty-first diode and the twentieth-two diode. In one embodiment of the present application, the microstrip line includes a two-stage matching microstrip, a three-stage matching microstrip, and an output matching microstrip line, the second-stage pairs of diodes include the seventeenth diode to the twenty-second diode, and the third-stage pairs of diodes include the twenty-first diode and the twentieth-two diode. In one embodiment of the present application, the microstrip line includes a two-stage matching microstrip, a three-stage matching microstrip, and an output matching microstrip line, the second-stage pairs of diodes include the seventeenth diode to the twenty-second diode, and the third-stage pairs of diodes include the twenty-first diode and the twentieth-two diode.

[0012] In one embodiment of the present application, each group of first-stage pair tubes, each group of second-stage pair tubes and each group of third-stage pair tubes are gallium nitride Schottky diode pair tubes.

[0013] In one embodiment of the present application, the anode width of the gallium nitride Schottky diode in each group of first-stage pair tubes is 400 microns; the anode width of the gallium nitride Schottky diode in each group of second-stage pair tubes is 300 microns; the anode width of the gallium nitride Schottky diode in each group of third-stage pair tubes is 200 microns.

[0014] Another aspect of the present application provides a gallium nitride limiting amplifier chip, comprising the tree structure-based gallium nitride limiting amplifier circuit according to any one of the above embodiments.

[0015] Compared with the prior art, the present application has the following advantages: (1) The present application provides a tree structure-based gallium nitride limiting amplifier circuit, which increases a group of first-stage pair tubes in the first-stage limiting unit by means of the tree structure, i.e., the first-stage limiting unit comprises two groups of first-stage pair tubes, so that the power capacity of the limiting amplifier circuit can be improved while ensuring low insertion loss compared with the conventional limiting amplifier circuit.

[0016] (2) The present application connects two groups of first-stage pair tubes by means of the tree structure, which can uniformly distribute the microwave signal to different paths, which helps to disperse the energy of the input microwave signal and avoid a single path from bearing too high power, thereby improving the power handling capacity of the entire limiting amplifier circuit.

[0017] (3) The tree structure designed in the present application is conducive to better impedance matching, reducing reflection loss and ensuring efficient transmission of the microwave signal between limiting units at different levels, and good impedance matching is one of the key factors to maintain the stability of the radio frequency / microwave system and maximize power transmission, especially in high-power applications.

[0018] (4) Since electronic components are prone to nonlinear distortion under the condition of high-power microwave signals, the present application can make the load between the limiting units at different levels more balanced by reasonable tree structure design, reduce nonlinear problems caused by uneven power and ensure the quality of signal transmission.

[0019] (5) Compared with the prior art, the tree structure-based gallium nitride limiting amplifier circuit provided by the present application does not require additional inductors or power division and combination structures, so the circuit process is relatively simple, and the power capacity of the gallium nitride Schottky diode is also higher, which can greatly improve the power capacity of the gallium nitride limiting amplifier chip.

[0020] The application will be described in further detail in connection with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of a gallium nitride limiting amplifier circuit based on a tree structure provided by an embodiment of the application; Figure 2 is a schematic layout of a gallium nitride limiting amplifier chip provided by an embodiment of the application; Figure 3 is a simulation result diagram of the insertion loss of a gallium nitride limiting amplifier chip provided by an embodiment of the application; Figure 4 is a simulation result diagram of the input standing wave of a gallium nitride limiting amplifier chip provided by an embodiment of the application; Figure 5 is a simulation result diagram of the output power of a gallium nitride limiting amplifier chip provided by an embodiment of the application. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined object, a gallium nitride limiting amplifier circuit based on a tree structure according to the application is described in detail below in connection with the accompanying drawings and specific embodiments.

[0023] The foregoing and other technical contents, features and effects of the application can be clearly presented in the detailed description of the specific embodiments below in connection with the accompanying drawings. Through the description of the specific embodiments, the technical means and effects adopted by the application to achieve the predetermined object can be understood more deeply and specifically. However, the accompanying drawings are provided for reference and illustration only, and are not intended to limit the technical solutions of the application.

[0024] It should be noted that, in this document, relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0025] The application proposes a gallium nitride limiting amplifier circuit based on a tree structure to solve the problem of how to improve the power tolerance of the limiting amplifier circuit while reducing the complexity of the circuit process, please refer to Figure 1The circuit 100 comprises a first-stage limiting unit 101, a second-stage limiting unit 102, and a third-stage limiting unit 103 connected in sequence.

[0026] Specifically, as shown in Figure 1 the first-stage limiting unit 101 comprises two groups of first-stage pair tubes (i.e., a first group of first-stage pair tubes 1011 and a second group of first-stage pair tubes 1012) and a tree structure T, the tree structure T connects the two groups of first-stage pair tubes 1011, and the two groups of first-stage pair tubes 1011 are located on both sides of the tree structure T.

[0027] The tree structure T is a hierarchical and branched network layout, similar to the shape of a tree. It starts from a central node (root node), expands through multiple branch nodes, and finally reaches multiple end nodes (leaf nodes). The first group of first-stage pair tubes 1011 and the second group of first-stage pair tubes 1012 are both pair tubes formed by left and right links.

[0028] In some embodiments, as shown in Figure 1 the tree structure T comprises a first tree structure T1 and a second tree structure T2, a first end of the first tree structure T1 is connected to the first group of first-stage pair tubes 1011, a second end of the first tree structure T1 is connected to a second end of the second tree structure T2, and a first end of the second tree structure T2 is connected to the second group of first-stage pair tubes 1012.

[0029] It should be noted that in the embodiments of the present application, the first tree structure T1 and the second tree structure T2 have the same structure, which ensures that the input microwave signal is evenly distributed to the first group of first-stage pair tubes 1011 and the first group of first-stage pair tubes 1011, avoids the concentration of high-power microwave signals on a single path, makes the load between the first group of first-stage pair tubes 1011 and the first group of first-stage pair tubes 1011 more balanced, reduces the nonlinear problems caused by uneven power, and ensures the quality of signal transmission. The first tree structure T1 and the second tree structure T2 each comprise a plurality of microstrip lines.

[0030] In some embodiments, as shown in Figure 1 the first group of first-stage pair tubes 1011 comprises first to eighth diodes D1-D8, the second group of first-stage pair tubes 1012 comprises ninth to sixteenth diodes D9-D16, and the first ends of the first tree structure T1 and the second tree structure T2 each comprise a first branch and a second branch.

[0031] The first branch T11 of the first tree structure T1 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the cathode of the second diode D2, the anode of the second diode D2 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the cathode of the fourth diode D4, the anode of the fourth diode D4 is grounded, the first branch T12 of the first tree structure T1 is connected to the anode of the fifth diode D5, the cathode of the fifth diode D5 is connected to the anode of the sixth diode D6, the cathode of the sixth diode D6 is connected to the anode of the seventh diode D7, the cathode of the seventh diode D7 is connected to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is grounded. The first branch T21 of the second tree structure T2 is connected to the anode of the ninth diode D9, the cathode of the ninth diode D9 is connected to the anode of the twelfth diode D10, the cathode of the twelfth diode D10 is connected to the anode of the eleventh diode D11, the cathode of the eleventh diode D11 is connected to the anode of the twelfth diode D12, the cathode of the twelfth diode D12 is grounded, the first branch T22 of the second tree structure T2 is connected to the cathode of the thirteenth diode D13, the anode of the thirteenth diode D13 is connected to the cathode of the fourteenth diode D14, the anode of the fourteenth diode D14 is connected to the cathode of the fifteenth diode D15, the anode of the fifteenth diode D15 is connected to the cathode of the sixteenth diode D16, and the anode of the sixteenth diode D16 is grounded.

[0032] In some embodiments, as shown in FIG. 1, the first-stage limiting unit 101 includes a set of first-stage diodes 1011, the second-stage limiting unit 102 includes a set of second-stage diodes 1021, and the third-stage limiting unit 103 includes a set of third-stage diodes 1031. Figure 1

[0033] In some embodiments, as shown in FIG. 1, the first-stage limiting unit 101 includes a set of first-stage diodes 1011, the second-stage limiting unit 102 includes a set of second-stage diodes 1021, and the third-stage limiting unit 103 includes a set of third-stage diodes 1031. Figure 1

[0034] Specifically, the first-stage limiting unit 101 and the second-stage limiting unit 102 are connected through a first-stage-second-stage matching microstrip L2, and the second-stage limiting unit 102 and the third-stage limiting unit 103 are connected through a second-stage-third-stage matching microstrip L3.

[0035] In some embodiments, as shown in FIG. 1, the first-stage limiting unit 101 includes a set of first-stage diodes 1011, the second-stage limiting unit 102 includes a set of second-stage diodes 1021, and the third-stage limiting unit 103 includes a set of third-stage diodes 1031. Figure 1

[0036] Specifically, the input port 104 and the first-stage limiting unit 101 are connected through an input matching microstrip L1, and the output port 105 and the third-stage limiting unit 103 are connected through an output matching microstrip L4.

[0037] ​​​In some embodiments, the second-stage pair of tubes 1021 includes a seventeenth diode D17 and a twenty-second diode D20, and the third-stage pair of tubes 1031 includes a twenty-first diode D21 and a twentieth-two diode D22.

[0038] In some embodiments, the anode of the seventeenth diode D17 is connected to the cathode of an eighteenth diode D18, the anode of the eighteenth diode D18 is connected to ground, the cathode of the seventeenth diode D17 and the anode of a nineteenth diode D19 are connected between a first-stage matching microstrip L2 and a second-stage matching microstrip L3, the cathode of the nineteenth diode D19 is connected to the anode of the twenty-second diode D20, and the cathode of the twenty-second diode D20 is connected to ground.

[0039] In some embodiments, the anode of the twenty-first diode D21 is connected to ground, the cathode of the twenty-first diode D21 and the anode of the twentieth-two diode D22 are connected between the second-stage matching microstrip L3 and an output matching microstrip L4, and the cathode of the twentieth-two diode D22 is connected to ground.

[0040] In some embodiments, each of the first-stage pair of tubes 1101, each of the second-stage pair of tubes 1102, and each of the third-stage pair of tubes 1103 in the embodiments of the present application are gallium nitride Schottky diode pairs.

[0041] It should be noted that, since the gallium nitride material has a wider band gap than the traditional gallium arsenide material of the limiting amplifier circuit, the use of the gallium nitride material for the diodes can make the limiting amplifier circuit have higher power capacity, i.e., can improve the power tolerance of the limiting amplifier circuit; in addition, since the gallium nitride material has high thermal conductivity, combined with the distributed layout of the tree structure, heat can be more effectively dispersed, the risk of local overheating can be reduced, and thus the stability of the limiting amplifier circuit under high power conditions can be improved.

[0042] In addition, considering that the first-stage limiting unit 101 faces the maximum energy of the input microwave signal, a larger size device (i.e., a wider anode) is needed to withstand high power, as the microwave signal passes through each stage of the limiting unit, the power is gradually absorbed or clamped, and the power handling capability of the subsequent stage limiting unit decreases, a smaller size device can be used, therefore, in order to avoid overloading and damage of the first-stage limiting unit 101, the size of the second-stage limiting unit 102 and the third-stage limiting unit 103 is too large, which increases the parasitic effect and affects the high-frequency performance, in the embodiments of the present application, the anode width of the gallium nitride Schottky diode in each of the first-stage pair of tubes 1101 is 400 microns, the anode width of the gallium nitride Schottky diode in each of the second-stage pair of tubes 1102 is 300 microns, and the anode width of the gallium nitride Schottky diode in each of the third-stage pair of tubes 1103 is 200 microns, so as to improve the stability and life of the first-stage limiting unit 101, and to avoid the increase of the parasitic effect due to the size of the latter two limiting units being too large, and to reduce the area of the two limiting units.

[0043] In summary, the gallium nitride limiting circuit based on the tree structure provided by the embodiment of the application has the following advantages: (1) The first-stage limiting unit is increased with a group of first-stage pair tubes through the tree structure, that is, the first-stage limiting unit includes two groups of first-stage pair tubes, so that the power capacity of the limiting circuit can be improved while ensuring low insertion loss compared with the traditional limiting circuit.

[0044] (2) The two groups of first-stage pair tubes are connected through the tree structure, so that the microwave signal can be evenly distributed to different paths, which helps to disperse the energy of the input microwave signal and avoid a single path from bearing too high power, thereby improving the power handling capacity of the entire limiting circuit.

[0045] (3) The tree structure is conducive to better impedance matching, reduces reflection loss, and ensures efficient transmission of the microwave signal between different levels of limiting units.

[0046] (4) Since electronic components are prone to nonlinear distortion under high-power microwave signals, the reasonable tree structure design can make the load between the limiting units more balanced, reduce nonlinear problems caused by uneven power, and ensure the quality of signal transmission.

[0047] (5) Compared with the prior art, the gallium nitride limiting circuit based on the tree structure provided by the application does not require an additional inductor, the limiting circuit is simpler, and the power capacity of the gallium nitride Schottky diode is higher, which can greatly improve the power capacity of the gallium nitride limiter chip.

[0048] It should be understood that in the several embodiments provided by the application, the division of units / modules is only a logical functional division, and actual implementation can have another division manner, for example, multiple units / modules or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0049] Another embodiment of the application provides a gallium nitride limiting chip, which includes the gallium nitride limiting circuit based on the tree structure described in the above embodiments.

[0050] It should be noted that the tree structure T in the embodiment of the application can be provided in each level of limiting unit, and can also be nested as needed to directly greatly improve the power capacity of the first-stage limiting unit 101 without using power division and power combination structure, so as to facilitate the miniaturization of the gallium nitride limiter chip.

[0051] For example, please see Figure 2 , Figure 2 This is a schematic layout of a gallium nitride limiting chip provided in an embodiment of the present invention. Wherein, as... Figure 2 As shown, the size of the gallium nitride limiting chip is 3.1mm*1.6mm, which means that the overall size of the gallium nitride limiting circuit is relatively small. The dotted line part in the figure is a schematic physical diagram of the tree structure designed in this invention.

[0052] Figures 3-5 for Figure 3 The simulation performance of the gallium nitride limiting chip shown is as follows: Figure 3 As shown, at frequency ( Figure 3 When the frequency (freq) is 8GHz, S(2,1) = -0.531dB. The insertion loss of the gallium nitride (GaN) limiting chip is the absolute value of S(2,1), that is, the insertion loss m1 of the GaN limiting chip is 0.531dB. Similarly, at a frequency of 12GHz, the insertion loss m2 of the GaN limiting chip is 0.495dB. Therefore, it can be seen that the insertion loss of the GaN limiting chip is less than 0.55dB within the frequency range of 8~12GHz, meaning the insertion loss is relatively small. Figure 4 As shown, at frequency ( Figure 4 The freq in the figure represents the input standing wave ratio (VSWR) of the gallium nitride limiting chip at 8 GHz. Figure 4 The VSWR1)m3=1.723, and the input VSWR of the gallium nitride limiting chip at a frequency of 12GHz is m4=1.098. This shows that the input VSWR of the gallium nitride limiting chip is less than 1.75 within the frequency range of 8~12GHz, indicating a relatively small input VSWR. Figure 5 As shown, at the input power ( Figure 5 When the input power is 50dBm (100W), the output power m5 of the gallium nitride limiting chip at three different frequency measurement points is 26.877dBm, 25.832dBm and 24.588dBm, respectively. It can be seen that the output frequency m5 of the gallium nitride limiting chip is less than 27dBm (0.5W), that is, the output frequency is much less than the input power of 50dBm.

[0053] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A tree-structure-based gallium nitride limiter circuit, comprising: The application relates to a tree-shaped gallium nitride limiting circuit. The first limiting unit comprises two groups of first-stage pairs of tubes and a tree-shaped structure, the tree-shaped structure is connected with the two groups of first-stage pairs of tubes, and the two groups of first-stage pairs of tubes are located on two sides of the tree-shaped structure. The tree-shaped structure comprises a first tree-shaped structure and a second tree-shaped structure.

2. The tree structure based GaN limiting circuit of claim 1, wherein, The first end of the first tree-shaped structure is connected with a first group of first-stage pairs of tubes, the second end of the first tree-shaped structure is connected with the second end of the second tree-shaped structure, and the first end of the second tree-shaped structure is connected with a second group of first-stage pairs of tubes. The first tree-shaped structure and the second tree-shaped structure are identical.

3. The tree structure based GaN limiting circuit of claim 2, wherein, The first group of first-stage pairs of tubes comprises a first diode to an eighth diode, the second group of first-stage pairs of tubes comprises a ninth diode to a sixteenth diode, and the first end of the first tree-shaped structure and the first end of the second tree-shaped structure each comprise a first branch and a second branch.

4. The tree structure based GaN limiting circuit of claim 2, wherein, The first branch of the first tree-shaped structure is connected with the cathode of the first diode, the anode of the first diode is connected with the cathode of a second diode, the anode of the second diode is connected with the cathode of a third diode, the anode of the third diode is connected with the cathode of a fourth diode, the anode of the fourth diode is grounded, the second branch of the first tree-shaped structure is connected with the anode of a fifth diode, the cathode of the fifth diode is connected with the anode of a sixth diode, the cathode of the sixth diode is connected with the anode of a seventh diode, the cathode of the seventh diode is connected with the anode of an eighth diode, and the cathode of the eighth diode is grounded. The first branch of the second tree-shaped structure is connected with the anode of a ninth diode, the cathode of the ninth diode is connected with the anode of a twelfth diode, the cathode of the twelfth diode is connected with the anode of an eleventh diode, the cathode of the eleventh diode is connected with the anode of a tenth diode, the cathode of the tenth diode is grounded, the second branch of the second tree-shaped structure is connected with the anode of a thirteenth diode, the cathode of the thirteenth diode is connected with the anode of a fourteenth diode, the anode of the fourteenth diode is connected with the cathode of a fifteenth diode, the anode of the fifteenth diode is connected with the cathode of a sixteenth diode, and the anode of the sixteenth diode is grounded. The first limiting unit, the second limiting unit and the third limiting unit are connected through a microstrip line. The second limiting unit comprises a group of second-stage pairs of tubes, and the third limiting unit comprises a group of third-stage pairs of tubes. The microstrip line comprises a two-stage matching microstrip, a three-stage matching microstrip and an output matching microstrip line, the second-stage pairs of tubes comprise a seventeenth diode to a twenty-second diode, and the third-stage pairs of tubes comprise a twenty-first diode and a twentieth-two diode.

6. The tree structure based GaN limiting circuit of claim 5, wherein, ​ 7. The tree structure based GaN limiting circuit of claim 6, wherein, ​ An anode of the seventeenth diode is connected to a cathode of an eighteenth diode, an anode of the eighteenth diode is grounded, a cathode of the seventeenth diode and an anode of a nineteenth diode are connected between the first-level matching microstrip and the second-level third-level matching microstrip, a cathode of the nineteenth diode is connected to an anode of a twenty-second diode, and a cathode of the twenty-second diode is grounded. An anode of a twenty-first diode is grounded, a cathode of the twenty-first diode and an anode of a twentieth-two diode are connected between the second-level third-level matching microstrip and the output matching microstrip line, and a cathode of the twentieth-two diode is grounded. 8.The tree-structure-based gallium nitride limiting amplifier circuit of claim 6, wherein each of the first-stage pair of diodes, each of the second-stage pair of diodes, and each of the third-stage pair of diodes is a pair of gallium nitride Schottky diodes. 9.The tree-structure-based gallium nitride limiting amplifier circuit of claim 6, wherein an anode width of each of the gallium nitride Schottky diodes in the first-stage pair of diodes is 400 micrometers. 10.A gallium nitride limiting amplifier chip comprising the tree-structure-based gallium nitride limiting amplifier circuit of any one of claims 1 to 9. ​ ​ ​ ​

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