Millimeter wave GaN power amplifier and heat dissipation structure thereof

Abstract

The utility model belongs to the field of power amplifiers, and particularly relates to a millimeter wave GaN power amplifier and a heat dissipation structure thereof, which comprise a power amplification circuit, and are characterized in that the input end of the power amplification circuit is connected with a porcelain input matching circuit, and the output end of the power amplification circuit is connected with a porcelain output matching circuit; the output end of the output matching circuit is connected with a waveguide module, and the waveguide module is connected with a waveguide coaxial adapter. The drain electrode input end of the power amplification circuit is coupled with a protection circuit. According to the protection circuit disclosed by the utility model, the gate voltage and the stable output state of the enable signal in the protection circuit are used as trigger signals through the logic control circuit to control the opening of the drain voltage, and the protection circuit can convert and generate the gate voltage required by the gate of the radio frequency power amplifier; therefore, a protection effect on the power amplifier is achieved, and the power amplifier circuit and the power amplifier are prevented from being damaged by overhigh voltage caused by power-on time sequence errors and misoperation in the power-on process.

Description

Technical Field

[0001] The utility model relates to the technical field of power amplifiers, in particular to a millimeter wave GaN power amplifier and a heat dissipation structure thereof. Background Art

[0002] With the development of 5G communication technology, the demand for higher data transmission rates and lower latency is growing, which makes the millimeter wave frequency band one of the research areas that has attracted much attention. Due to its large bandwidth and frequency resources, the 24-27GHz frequency band is widely considered to be an important part of the 5G system, which can support high-speed data transmission and large-capacity communication needs.

[0003] In the communication system of 24-27GHz frequency band, the power amplifier is one of the key radio frequency (RF) front-end components, which plays a vital role in signal enhancement and transmission. GaN technology can work in a higher frequency range, which enables GaN RF power amplifiers to adapt to the high frequency operation required by 5G communication systems. However, GaN power amplifiers are depletion-type devices, and their gate voltage and drain voltage have extremely stringent requirements on power-on and power-off timing. When powering on, the GaN power amplifier needs the gate voltage to power on before the drain voltage; when powering off, the GaN power amplifier needs the gate voltage to power off after the drain voltage. If the gate and drain of the GaN power amplifier have power-on timing errors or logical confusion, the GaN power amplifier will burn out and fail to work. Utility Model Content

[0004] The utility model aims to provide a millimeter wave GaN power amplifier and a heat dissipation structure thereof, which can solve the problem of device burning caused by the power-on timing of the power amplifier.

[0005] To this end, the technical solution adopted in this utility model is:

[0006] A millimeter wave GaN power amplifier, comprising a power amplifier circuit, characterized in that the input end of the power amplifier circuit is connected to a ceramic input matching circuit, the output end is connected to a ceramic output matching circuit, the output end of the ceramic output matching circuit is connected to a waveguide module, and the waveguide module is connected to a waveguide coaxial conversion head;

[0007] The drain input terminal of the power amplifier circuit is coupled to a protection circuit, and the protection circuit uses the gate voltage and the stable output state of the enable signal inside the protection circuit as a trigger signal to control the opening of the drain voltage.

[0008] Based on the above technical solution, its use principle and the technical effects produced are as follows:

[0009] In actual use, the power amplifier circuit will generate a judgment voltage through U2, U6, U1 and U3, such as the -6V voltage in the figure. If the voltage generated by the U3 unit is equal to -6V, it will generate the gate voltage of the amplifier circuit through U5 to power the gate. Figure 2 The -1.2V voltage generated as shown in the figure is the gate voltage of the amplifier circuit; if the voltage generated by U3 is not equal to -6V, the situation where a voltage not equal to -6V is generated here generally only occurs when the external supply drain voltage is too high. At this time, the circuit protection mechanism will react and completely shut down the entire circuit, thereby protecting the entire power amplifier.

[0010] In a preferred example, the utility model can be further configured as follows: the interior of the waveguide module is set as a cavity, the waveguide module includes a first rectangular segment, the end of the first rectangular segment is connected to a first circular arc segment, the end of the first circular arc segment is connected to a second rectangular segment, the end of the second rectangular segment is connected to a second circular arc segment, the end of the second circular arc segment is connected to a third circular arc segment, and the end of the third circular arc segment is connected to a third rectangular segment.

[0011] In a preferred example, the utility model can be further configured as follows: the cross-sectional shapes of the first arc segment and the second arc segment are both quarter arcs, and the inner arc radius of the first arc segment, the second arc segment and the third arc segment is 3 mm, and the outer arc radius is 6.56 mm;

[0012] The lengths of the first rectangular segment, the second rectangular segment, and the third rectangular segment are 8.29 mm, 1 mm, and 4.16 mm, respectively, and the widths of the first rectangular segment, the second rectangular segment, and the third rectangular segment are all 3.56 mm.

[0013] In a preferred example, the utility model can be further configured as follows: the protection circuit includes:

[0014] An overcurrent detection protection circuit, for receiving an adjusted bias voltage;

[0015] A negative feedback regulation circuit, used for receiving and regulating the enable voltage signal, and generating an overcurrent signal according to the enable signal;

[0016] The control module is used to receive the overcurrent signal to control the working state of the radio frequency power amplifier.

[0017] In a preferred example, the utility model can be further configured as follows: the overcurrent detection protection circuit includes U2, U6 and U1, the input end of U2 is connected to the external drain power input end for receiving the drain voltage, the output end of U2 is connected to the input end of U6, the output end of U6 is connected to the input end of U1, and U6 also receives an external high-level signal, the high-level signal is input to U6 from the high voltage side, and the phase is kept unchanged by U6 to output a stable voltage to power U1.

[0018] In a preferred example, the utility model can be further configured as follows: the protection circuit also includes U3, which is connected to the output end of U1 and is used to receive the output voltage of U1 and generate a reverse voltage of constant magnitude, and the output end of U3 is connected to the negative feedback regulation circuit (32).

[0019] In a preferred example, the utility model can be further configured as follows: the negative feedback regulation circuit includes U5, U7 and U2, the output end of U5 is connected to the input end of U7, the output end of U7 is connected to the enable input end of U2, and the output voltage signal of U7 and the output voltage signal of U6 jointly generate an enable signal that enters the enable input end of U2.

[0020] In a preferred example, the utility model can be further configured as follows: the control module (33) includes U1 and U2, wherein U1 is a linear regulator and U2 is a voltage regulator.

[0021] In a preferred example, the utility model can be further configured as follows: the power amplifier circuit is a three-stage amplifier circuit, and the power amplifier circuit is connected to the ceramic input matching circuit and the ceramic output matching circuit through bonding wires.

[0022] According to one aspect of the utility model, the utility model provides a radio frequency power amplifier heat dissipation mechanism, which is applied to a millimeter wave GaN power amplifier and includes multiple groups of heat dissipation fins, and the multiple groups of heat dissipation fins are all fixed on the outer side wall of the radio frequency power amplifier.

[0023] Furthermore: the heat sink fins are made of copper, and the heat sink fins are overall configured in a plate shape.

[0024] The nouns, conjunctions or adjectives involved in the above technical solution are explained as follows:

[0025] Fixed connection refers to a connection in which parts or components are fixed without any relative movement. There are two types of connection: detachable and non-detachable.

[0026] (1) A removable connection is a connection that uses screws, splines, wedge pins, etc. to hold parts together. This type of connection can be disassembled for maintenance without damaging the parts. However, the specifications of the connectors used must be correct (such as the length of the bolts, keys, and wedge pins) and they must be properly tightened.

[0027] (2) Non-detachable connections mainly refer to welding, riveting and tenoning. Since they need to be disassembled by forging, sawing or oxygen cutting for maintenance or replacement, spare parts generally cannot be reused. At the same time, when making connections, attention should be paid to process quality, technical inspection and remedial measures (such as calibration, polishing, etc.);

[0028] An active connection is a connection in which parts or components are fixed so that they can move relative to each other.

[0029] The above technical solution of the utility model has the following beneficial technical effects:

[0030] 1. A protection circuit is provided in the utility model. The protection circuit controls the opening of the drain voltage by using the gate voltage and the stable output state of the enable signal inside the protection circuit as a trigger signal through a logic control circuit. The protection circuit can convert and generate the gate voltage required by the gate of the RF power amplifier, thereby playing a protective role for the power amplifier device and will not cause damage to the power amplifier circuit and the device due to excessive voltage caused by power-on timing errors and erroneous operations during the power-on process.

[0031] 2. The heat dissipation mechanism described in the utility model can effectively dissipate the heat of the power amplifier, ensuring that the power amplifier will not cause irreversible damage to the device due to excessively high temperature during long-term operation, thereby effectively improving the linear power of the RF power amplifier and meeting the requirements of the 5G communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the overall circuit diagram of the radio frequency power amplifier of the utility model;

[0033] Figure 2 A circuit diagram of the protection circuit of the utility model;

[0034] Figure 3 This is a schematic diagram of the actual test of the radio frequency power amplifier of the utility model;

[0035] Figure 4 This is the 24GHz input-gain relationship curve of the utility model;

[0036] Figure 5 It is a structural schematic diagram of the waveguide module of the utility model;

[0037] Figure 6 This is a schematic diagram of simulation results of the waveguide module of the utility model;

[0038] Figure 7 This is a schematic diagram of the structure of the radio frequency power amplifier of the utility model;

[0039] Figure 8 This is a schematic diagram of the structure of the heat dissipation fin of the utility model;

[0040] Fig. 9 Schematic diagram of thermal simulation using heat dissipation structure for RF power amplifier;

[0041] Fig.10 Schematic diagram of thermal simulation of an RF power amplifier without a heat dissipation structure.

[0042] Reference numerals:

[0043] 1. Power amplifier circuit; 2. Waveguide module; 21. First rectangular segment; 22. First circular segment; 23. Second rectangular segment; 24. Second circular segment; 25. Third circular segment; 26. Third rectangular segment; 3. Protection circuit; 31. Overcurrent detection protection circuit; 32. Negative feedback regulation circuit; 33. Control module; 4. Ceramic input matching circuit; 5. Ceramic output matching circuit; 6. Waveguide coaxial conversion head. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments of the present utility model and the features in the embodiments can be combined with each other without conflict.

[0045] Embodiment 1:

[0046] According to the concept of this application, Figures 1 to 6 An embodiment of a millimeter-wave GaN power amplifier for preventing device damage caused by misoperation is described. Specifically, the millimeter-wave GaN power amplifier is constructed as an integrated structure, which has a power amplifier circuit 1, a waveguide module 2, and a protection circuit 3. The protection circuit 3 uses the gate voltage and the stable output state of the enable signal inside the protection circuit 3 as a trigger signal through a logic control circuit to control the opening of the drain voltage. The protection circuit 3 can convert and generate the gate voltage required by the gate of the RF power amplifier, and play a protective role for the power amplifier device, and will not cause damage to the power amplifier circuit 1 and the device due to power-on timing errors and excessive voltages caused by erroneous operations during the power-on process.

[0047] In order to prevent the amplifier from being damaged due to misoperation during power-on, protective measures are taken in the power management part of the amplifier to ensure that the power-on sequence will not affect the amplifier module. The basic design idea is to use the logic control circuit to use the stable output state of the gate voltage as a trigger signal to control the opening of the drain voltage. The circuit structure of the GaN power amplifier is as follows: Figure 1 As shown, VD is the drain power supply port of the GaN power amplifier, VG1 is the gate power supply port of the amplifier, and VD and VG1 generate the gate voltage VG of the GaN power amplifier through the protection circuit 3.

[0048] Combination Figure 1-6 As shown, the millimeter wave GaN power amplifier provided by the utility model includes a power amplifier circuit 1, the input end of the power amplifier circuit 1 is connected to a ceramic input matching circuit 4, the output end is connected to a ceramic output matching circuit 5, the output end of the ceramic output matching circuit 5 is connected to a waveguide module 2, and the waveguide module 2 is connected to a waveguide coaxial conversion head;

[0049] The drain input terminal of the power amplifier circuit 1 is coupled to a protection circuit 3 . The protection circuit 3 uses the gate voltage and the stable output state of the enable signal inside the protection circuit 3 as a trigger signal to control the opening of the drain voltage.

[0050] According to the technical solution of this embodiment, the power amplifier circuit 1 is a three-stage amplifier circuit, and the power amplifier circuit 1 is connected to the ceramic input matching circuit 4 and the ceramic output matching circuit 5 through bonding gold wires. The RF signal directly enters the GaN RF power amplifier circuit 1 through the ceramic input matching circuit 4, flows through the waveguide, and then passes through the ceramic output matching circuit 5 to the waveguide coaxial adapter through the connection method of bonding gold wires to generate an RF output signal.

[0051] For the technical solution of this embodiment, Figure 5 The interior of the waveguide module 2 is configured as a cavity, and the waveguide module 2 includes a first rectangular segment 21, an end of the first rectangular segment 21 is connected to a first arc segment 22, an end of the first arc segment 22 is connected to a second rectangular segment 23, an end of the second rectangular segment 23 is connected to a second arc segment 24, an end of the second arc segment 24 is connected to a third arc segment 25, and an end of the third arc segment 25 is connected to a third rectangular segment 26.

[0052] Furthermore, the cross-sectional shapes of the first arc segment 22 and the second arc segment 24 are both quarter arcs, and the inner arc radius of the first arc segment 22, the second arc segment 24 and the third arc segment 25 is 3 mm, and the outer arc radius is 6.56 mm;

[0053] The lengths of the first rectangular segment 21, the second rectangular segment 23, and the third rectangular segment 26 are 8.29 mm, 1 mm, and 4.16 mm, respectively, and the widths of the first rectangular segment 21, the second rectangular segment 23, and the third rectangular segment 26 are all 3.56 mm.

[0054] Specifically, the ports of the waveguide module 2 are all processed with tiny arc chamfers, and the upper channel of the waveguide is a structure of two quarter arcs, namely, the first arc segment 22 and the second arc segment 24. The purpose of such processing is to reduce the reflection and scattering of the signal, minimize the signal loss, and improve the performance and efficiency of the waveguide.

[0055] Regarding the preparation of the waveguide module 2, considering the production process, the use of arc structures and partial rectangles can greatly reduce the difficulty of the manufacturing process, thereby ensuring the accuracy of the geometric process. The material of this section of the waveguide module 2 is CuMoCu copper alloy, which is easy to process and form, can realize complex waveguide design, and has good conductivity to effectively transmit radio frequency signals, which helps to reduce the loss during signal transmission;

[0056] It should be further explained that the operating frequency range of the waveguide module 2 is 24 GHz-27 GHz. After simulation testing, the loss of this section of the output waveguide at 24 GHz and 27 GHz is very small and can be ignored; (S11 (reflection coefficient) is negligible; S21 (transmission coefficient) has very small losses at 24 GHz and 27 GHz and can be ignored).

[0057] According to the technical solution of this embodiment, the protection circuit 3 uses the stable output state of the gate voltage as a trigger signal through the logic control circuit to control the opening of the drain voltage. The 100pF capacitors of the protection circuit 3 are all filter capacitors around the power supply to ensure efficient and smooth DC output of the power supply.

[0058] The protection circuit 3 comprises:

[0059] An overcurrent detection protection circuit 31 is used to receive an adjustment bias voltage;

[0060] A negative feedback regulation circuit 32, for receiving and regulating an enable voltage signal, and generating an overcurrent signal according to the enable signal;

[0061] The control module 33 is used to receive the overcurrent signal to control the working state of the RF power amplifier.

[0062] Among them, Figure 2As shown, the overcurrent detection protection circuit 31 includes U2, U6 and U1, the input end of U2 is connected to the external drain power input end for receiving the drain voltage, the output end of U2 is connected to the input end of U6, the output end of U6 is connected to the input end of U1, the input end of U2 receives the external VD=22V drain voltage, and then the output end of U2 generates a 20V voltage connected to the gate drive output end of U6, and at the same time, U6 requires an external high-level signal, which is used as a high-side non-reversing logic input. The signal is input from the high voltage side to U6, and U6 keeps the phase unchanged and outputs a 12V voltage to power U1;

[0063] It should be noted that the control module 33 includes U1 and U2, U2 is a voltage regulator, and U1 is a low-noise, low-dropout linear regulator. When the output voltage generated by U6 is higher than the U1 threshold or U1 receives an erroneous reverse voltage, the overcurrent signal is valid. At this time, the negative feedback circuit will not generate an enable signal, and the bias drive circuit stops working. At this time, the RF power amplifier enters the circuit protection mode.

[0064] Furthermore, the internal circuit of U1 not only has reverse voltage, current limiting and reverse current protection, but U1 also has over-temperature protection. The integrated circuit includes over-temperature protection to protect the device in the event of a momentary overload.

[0065] Among them, Figure 2 As shown, the protection circuit 3 also includes U3, which acts as a bridge in the entire protection circuit 3. U3 is connected to the output end of U1, receives the output voltage of U1, and generates a reverse voltage of constant magnitude. If the generated reverse voltage is within the threshold range of U5, the output voltage of U3 becomes the input voltage of U5; if the generated reverse voltage is not within the threshold range of U5, the circuit starts the protection mode, does not generate the gate voltage, and turns off the drain power supply; a part of U5 output generates the required gate voltage by controlling the size of different voltage-dividing resistors, and the other part of U5 output voltage is directly used as the input voltage of U7.

[0066] Among them, Figure 2As shown, the negative feedback regulation circuit 32 includes U5, U7 and U2. The output voltage signal of U7 and the output voltage signal of U6 jointly generate an enable signal and enter the enable input terminal of U2. The entire protection circuit 3 controls the working state of the RF power amplifier mainly through negative feedback regulation and multi-voltage coordination; (for example, the normality of U3 output voltage can directly trigger the protection mechanism; whether U5 can generate gate voltage controls the switch closure of drain voltage; U1's own overvoltage and overcurrent protection aims to prevent sudden surge in external voltage from directly damaging the RF circuit; whether U7 can normally generate enable signal controls the normal closed-loop operation of the entire protection circuit 3), U5 outputs -5V voltage, and the output terminal of U5 is connected to the input terminal of U7. U7 converts and generates enable signal and enters the enable input terminal of U2. U2 receives the enable signal to form a closed-loop stable working state of the entire protection circuit 3. The enable signal and the generated gate voltage can both be used as control signals for the drain voltage switch.

[0067] It should be further explained that U2 is a high-current, high-precision, low-dropout voltage regulator. U2 has an enable (EN) signal that allows the device to be controlled on / off. In the protection circuit 3, U2 can detect when the power amplifier temperature exceeds +125°C, and the thermal shutdown causes the device to fail. In addition, if the input voltage exceeds about 32V in the line transient protection, the overvoltage sensor disables the regulator and causes the device to fail. U6 is a 125V / 3A, high-speed, half-bridge MOSFET driver. IN_H is a high-side non-inverting logic input driven by voltage VG1. The signal is input into the circuit from the high voltage side and maintains the phase unchanged after passing through the circuit, ultimately generating a 12V voltage. U1 is a low-dropout linear regulator with very low output noise Due to this feature, it is very suitable for the application of this power amplifier power supply. The internal integrated circuit of U1 contains current limiting, reverse current and over-temperature protection, which can protect the GaN device when the maximum operating environment temperature exceeds 125℃ or in the case of instantaneous overload; U3 is a switched capacitor voltage converter that can be used to invert the input power supply voltage and can convert +6V voltage into -6V voltage; U5 is a micro-power low-noise, low-dropout negative regulator. U5 has a fixed output voltage of -5V and an adjustable reference voltage of -1.22V. Finally, the actual gate voltage VG=-1.2V is generated by U5. Therefore, during use, since the protection circuit 3 is designed for the GaN power amplifier circuit 1, there is actually no requirement for the power-on timing of VG1 and VD.

[0068] Specifically, if Figure 2 As shown, in actual use, the power amplifier circuit 1 will generate a judgment voltage through U2, U6, U1 and U3, such as the -6V voltage in the figure. If the voltage generated by the U3 unit is equal to -6V, it will generate the gate voltage of the amplifier circuit through U5 to power the gate, such as Figure 2The -1.2V voltage generated as shown in the figure is the gate voltage of the amplifier circuit; if the voltage generated by U3 is not equal to -6V, the situation where a voltage not equal to -6V is generated here generally only occurs when the external supply drain voltage is too high. At this time, the circuit protection mechanism will react and completely shut down the entire circuit, thereby protecting the entire power amplifier.

[0069] like Figure 3 As shown, a millimeter-wave GaN power amplifier in the present application is subjected to actual RF performance test, and a schematic diagram of the actual test of the RF power amplifier is shown. After completing the assembly and connection of the RF and power supply parts of the power amplifier module, a static power-on test is performed on the power amplifier module. Before power-on, the gate and drain resistances of the power amplifier chip are checked. Under normal circumstances, the gate resistance should be in the tens of megohms level, and the drain resistance is about 1 ohm. After confirming that there is no abnormality, power can be applied, and a 6V voltage is provided to the gate of the GaN chip and a 22V voltage is provided to the drain of the GaN chip. The RF input port is connected to a signal generator, and the RF output port is connected to a spectrum analyzer. The computer is connected to the USB interface of the spectrum analyzer to save the test data.

[0070] Under the condition of test frequency of 24GHz, the input-gain relationship curve is drawn according to the test results. Figure 4 As shown, the maximum gain of the power amplifier exceeds 28.6dB when it is working normally. The test results show that the amplification performance of the GaN power amplifier is far superior to that of the traditional RF power amplifier. The technical solution of this application can effectively improve the linear power of the RF power amplifier and has good heat dissipation performance, thereby meeting the requirements of the 5G communication system.

[0071] The millimeter wave GaN power amplifier provided by the present invention is further described below in conjunction with the accompanying drawings and implementation modes.

[0072] A millimeter wave GaN power amplifier comprises a power amplifier circuit 1, wherein the input end of the power amplifier circuit 1 is connected to a ceramic input matching circuit 4, the output end is connected to a ceramic output matching circuit 5, the output end of the output matching circuit is connected to a waveguide module 2, and the waveguide module 2 is connected to a waveguide coaxial conversion head;

[0073] The drain input terminal of the power amplifier circuit 1 is coupled to a protection circuit 3 . The protection circuit 3 uses the gate voltage and the stable output state of the enable signal inside the protection circuit 3 as a trigger signal to control the opening of the drain voltage.

[0074] Embodiment 2:

[0075] According to one aspect of the utility model, the utility model provides a radio frequency power amplifier heat dissipation mechanism, including multiple groups of heat dissipation fins, and the multiple groups of heat dissipation fins are all fixed on the outer side wall of the radio frequency power amplifier.

[0076] Furthermore: the heat sink fins are made of copper, and the heat sink fins are overall configured in a plate shape.

[0077] For the technical solution of this embodiment, Figure 8 As shown, the spacing between each group of heat sink fins is as equal as possible to avoid uneven heat dissipation caused by too large or too small spacing, and the heat sink fins are mainly made of copper alloy, and the lower cover and the side wall of the power amplifier are made of heat dissipation holes and metalized.

[0078] It should be noted that after the power chip is packaged into the tube shell, the entire power amplifier circuit 1 is Figure 7 As shown, the overall area of ​​the amplifier is 53*40mm. In the process of designing the power amplifier, it is considered that the waveguide and the interconnected bonding wires will increase the loss, especially the microstrip and waveguide from the chip to the output port at the output end of the GaN power amplifier circuit 1 will cause impedance mismatch. Therefore, in terms of circuit design, on the one hand, the heating of the GaN chip should be considered, and the length and curvature of the bonding wire should be simulated according to the space conditions of the chip, protection circuit 3, bonding wire, filter capacitor, tube shell, and SMA connector. The operating frequency band of the power amplifier is above the Ku band, so a 125μm low-loss and low-dielectric constant material microstrip line is bonded / sintered on the carrier to reduce transmission loss, and the length of the input and output bonding wires is controlled within 350μm. It is particularly important to note that eight gold wires need to be welded at the VD end and the RF output end to minimize the RF loss from the bonding gold wires and the output end of the GaN RF amplifier circuit to the SMA connector end. Finally, eight 25μm bonding gold wires are connected in parallel to match the input and output port impedance of the entire circuit to the optimal state of 50 ohms, ensuring high-power and high-efficiency output of the packaged chip.

[0079] like Figure 8 As shown in the figure, the main material of the heat dissipation structure of the RF power amplifier device is copper. The heat dissipation structure adopts a three-dimensional design, which can achieve more efficient heat dissipation in a limited space; secondly, the structure has a larger surface area and a more complex heat conduction path, so it can improve the heat dissipation performance; the irregular tooth structure is to increase the heat conduction path, reduce thermal resistance, and thus improve the heat conduction efficiency. This effectively solves the heat dissipation problem of high-power equipment such as power amplifiers and improves the stability and reliability of the equipment.

[0080] like Fig. 9As shown in the figure, the RF power amplifier is thermally simulated in Ansys. Steady-state thermal and transient thermal simulations are mainly performed in Ansys. The main parameters to be set are heat flow, heat flux, internal heat generation and convection. Heat flow is the heat dissipation power consumption of the chip. The specific parameters are calculated as follows:

[0081] Chip volume: V = 3.57 × 3.17 × 0.10 mm

[0082] Internal heat generation:

[0083] Heat flow: In actual analysis, it is necessary to convert it into heat flux (area) or internal heat generation (volume) according to the area or volume used. The heat dissipation power consumption of GaN chip is 25W, so the internal heat generation is 2.209×10 10 w / m 3 .

[0084] In order to compare and analyze the heat dissipation performance of power amplifiers, such as Figure 9-10 As shown, when the RF power amplifier device is thermally simulated with a fin-shaped heat dissipation structure, the heating temperature of the chip is 88°C to 100.4°C; under the same simulation parameter conditions, the power amplifier circuit 1 without a fin-shaped heat dissipation structure is thermally simulated as a whole. When the fin-shaped heat dissipation structure is not added, the heating temperature of the chip is 125°C-137.6°C; the results show that the heat dissipation structure can effectively solve the heat dissipation problem and effectively ensure that the heating temperature of the amplifier as a whole is far lower than the maximum storage temperature of the power amplifier of 150°C. The RF power amplifier has good overall heat dissipation. This structure is of great significance to extending the service life of the GaN chip and improving the thermal reliability of the device.

[0085] It should be noted that the other parts of the millimeter wave GaN power amplifier and the RF power amplifier heat dissipation mechanism provided by this application can be designed, manufactured and sold separately, or they can be assembled together and then sold as a whole. Regardless of the monomers formed before the combination or the whole formed after the combination, they all fall within the protection scope of this application.

[0086] In the present utility model, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The term "and / or" used in this article includes any and all combinations of one or more related listed items. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0087] It should be noted that when an element is referred to as being "assembled on", "installed on", "fixed on" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0088] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0089] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A millimeter wave GaN power amplifier, comprising a power amplifier circuit (1), characterized in that: The input end of the power amplifier circuit (1) is connected to a ceramic input matching circuit (4), and the output end is connected to a ceramic output matching circuit (5); the output end of the ceramic output matching circuit (5) is connected to a waveguide module (2), and the waveguide module (2) is connected to a waveguide coaxial conversion head; The drain input terminal of the power amplifier circuit (1) is coupled to a protection circuit (3), and the protection circuit (3) uses the gate voltage and the stable output state of the enable signal inside the protection circuit (3) as a trigger signal to control the opening of the drain voltage.

2. A millimeter wave GaN power amplifier according to claim 1, characterized in that: The interior of the waveguide module (2) is arranged as a cavity. The waveguide module (2) comprises a first rectangular segment (21), the end of the first rectangular segment (21) is connected to a first circular arc segment (22), the end of the first circular arc segment (22) is connected to a second rectangular segment (23), the end of the second rectangular segment (23) is connected to a second circular arc segment (24), the end of the second circular arc segment (24) is connected to a third circular arc segment (25), and the end of the third circular arc segment (25) is connected to a third rectangular segment (26).

3. A millimeter wave GaN power amplifier according to claim 2, characterized in that: The cross-sectional shapes of the first arc segment (22) and the second arc segment (24) are both quarter arcs, and the inner arc radius of the first arc segment (22), the second arc segment (24) and the third arc segment (25) is 3 mm, and the outer arc radius is 6.56 mm; The lengths of the first rectangular segment (21), the second rectangular segment (23), and the third rectangular segment (26) are 8.29 mm, 1 mm, and 4.16 mm, respectively, and the widths of the first rectangular segment (21), the second rectangular segment (23), and the third rectangular segment (26) are all 3.56 mm.

4. The millimeter wave GaN power amplifier according to claim 1, characterized in that: The protection circuit (3) comprises: An overcurrent detection protection circuit (31) is used to receive an adjusted bias voltage; A negative feedback regulation circuit (32) is used to receive and regulate an enable voltage signal, and generate an overcurrent signal according to the enable voltage signal; The control module (33) is used to receive an overcurrent signal to control the working state of the radio frequency power amplifier.

5. The millimeter wave GaN power amplifier according to claim 4, characterized in that: The overcurrent detection protection circuit (31) comprises U2, U6 and U1, wherein the input end of U2 is connected to the input end of an external drain power supply for receiving a drain voltage, the output end of U2 is connected to the input end of U6, the output end of U6 is connected to the input end of U1, and U6 also receives an external high-level signal, which is input to U6 from the high voltage side, and outputs a stable voltage through U6 while maintaining a constant phase to supply power to U1.

6. The millimeter wave GaN power amplifier according to claim 5, characterized in that: The protection circuit (3) further comprises U3, which is connected to the output end of U1 and is used to receive the output voltage of U1 and generate a reverse voltage of constant magnitude, and the output end of U3 is connected to a negative feedback regulation circuit (32) (32).

7. The millimeter wave GaN power amplifier according to claim 6, characterized in that: The negative feedback regulation circuit (32) comprises U5, U7 and U2, the output end of U5 is connected to the input end of U7, the output end of U7 is connected to the enable input end of U2, and the output voltage signal of U7 and the output voltage signal of U6 jointly generate an enable signal which enters the enable input end of U2.

8. The millimeter wave GaN power amplifier according to claim 7, characterized in that: The control module (33) (33) includes U1 and U2, wherein U1 is a linear regulator and U2 is a voltage regulator.

9. The millimeter wave GaN power amplifier according to claim 1, characterized in that: The power amplifier circuit (1) is a three-stage amplifier circuit, and the power amplifier circuit (1) is connected to the ceramic component input matching circuit (4) and the ceramic component output matching circuit (5) through bonding gold wires.

10. A radio frequency power amplifier heat dissipation structure, applied to a millimeter wave GaN power amplifier according to any one of claims 1 to 9, characterized in that: It comprises a plurality of groups of heat dissipation fins, and the plurality of groups of heat dissipation fins are all fixed on the outer side wall of the radio frequency power amplifier.

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