Solid-state microwave source

Abstract

The invention belongs to the field of microwave heating, and discloses a solid-state microwave source which comprises a circuit board and a radio frequency connector connected with the circuit board, a heating element is arranged on the circuit board and connected with a first heat dissipation component through a heat sink, and one side, away from the first heat dissipation component, of the circuit board is detachably connected with a cover plate. An installation step is arranged on the surface of the first heat dissipation component and extends to at least one side edge of the first heat dissipation component, the heat sink is arranged in the installation step, and a second heat dissipation component is fixedly connected in the installation step and outside the side edge of the heat sink. The heat sink is arranged on the surface of the heat dissipation component through an open type step structure, the heat dissipation effect is further enhanced, a heating component and a radio frequency load which are prone to damage can be independently pulled out under the condition that a cover plate is not opened, replacement is more convenient, repeated work of secondary melting of welding spots to release stress is avoided, and the service life of the heat sink is prolonged. And the microwave oven is better in safety performance, free of maintenance, long in service life and suitable for microwave generation.

Description

Technical Field

[0001] The invention belongs to the field of microwave heating, in particular to a solid-state microwave source. Background Art

[0002] In recent years, the microwave heating market has expanded year by year, and the demand for solid-state microwave sources has also increased day by day. With the advancement of gallium nitride material technology, especially the rapid development of high-power gallium nitride RF chips driven by 5G technology, the power level of solid-state microwave sources has also gradually increased. With the advantages of controllable power, frequency and phase, solid-state microwave sources are showing a trend of replacing old heating technologies such as magnetrons in the field of microwave heating.

[0003] However, during the operation of the solid-state microwave source, the final power amplifier tube in the radio frequency circuit generates a large amount of heat, making the heat dissipation capacity the main reason restricting the development of the solid-state microwave source. The Chinese utility model patent with the authorization announcement number CN212277180 discloses a solid-state source and cooking equipment, which improves the heat dissipation capacity of the solid-state source by a substrate attached to the heating element. Although the heat dissipation is enhanced to a certain extent, the heat dissipation effect is still limited. Summary of the invention

[0004] In order to solve the above deficiencies in the prior art, the present invention aims to provide a solid-state microwave source to further enhance the heat dissipation effect.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a solid-state microwave source, including a circuit board and a radio frequency connector connected to the circuit board, a heating element is provided on the circuit board, the heating element is connected to a first heat dissipation component through a heat sink, a cover plate is detachably connected to the side of the circuit board away from the first heat dissipation component, a mounting step is provided on the surface of the first heat dissipation component, the mounting step extends to at least one side edge of the first heat dissipation component, the heat sink is arranged in the mounting step, and a second heat dissipation component is fixedly connected inside the mounting step and outside the side edge of the heat sink.

[0006] As a limitation of the present invention: the second heat dissipation component is adapted to the side edge size of the heat sink, and a tooth-shaped heat dissipation structure is formed on the second heat dissipation component.

[0007] As a limitation of the present invention: the mounting step extends to two adjacent outer edges of the first heat dissipation component, the second heat dissipation component is fixed at one of the outer edges of the mounting step, and the edge of the heat sink extends to the other outer edge of the mounting step; The circuit board comprises a disassembly plate fixedly connected to the heat sink and flush with the outer edge of the heat sink, and a control board fixedly connected to the first heat dissipation component, so that the heat sink, the disassembly plate and the heat-generating component can be withdrawn from the solid-state microwave source together.

[0008] As a limitation of the present invention: the disassembly version includes a power amplifier matching circuit board for setting a heating element, and also includes a radio frequency load circuit board for setting a radio frequency load, and the power amplifier matching circuit board and the radio frequency load circuit board are independent of each other; the heat sink includes a power amplifier matching heat sink flush with the power amplifier matching circuit board, and also includes a radio frequency load heat sink flush with the radio frequency load circuit board, and the power amplifier matching heat sink and the radio frequency load heat sink are independent of each other, so that the power amplifier matching circuit board and the power amplifier matching heat sink can be pulled out from the solid-state microwave source together, and the radio frequency load circuit board and the radio frequency load heat sink can be pulled out from the solid-state microwave source together.

[0009] As a limitation of the present invention: the radio frequency connector is connected to the circuit board by extending to the outer edge of the mounting step through the heat sink.

[0010] As a limitation of the present invention: a flexible metal is filled between the heat sink and the first heat dissipation component.

[0011] As a limitation of the present invention: a connector bracket is fixedly connected to the edge of the heat sink, so that the lower part of the RF connector is fixedly connected to the heat sink, and the upper part is fixedly connected to the connector bracket.

[0012] As a limitation of the present invention: the connector bracket is provided with an avoidance groove for facilitating the connection of the radio frequency connector with the ceramic strip line of the circuit board.

[0013] As a limitation of the present invention: the cover plate is an integrated cover plate, and a partition wall for dividing the cavity is arranged on the side of the cover plate facing the circuit board.

[0014] As a limitation of the present invention: the heat sink is a copper plate.

[0015] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: (1) The heat sink of the present invention is arranged on the surface of the heat dissipation component through an open "step" structure. Compared with the closed "cavity" structure, the open "step" structure not only enables the heat sink to dissipate heat to one side of the first heat dissipation component, but also to dissipate heat to the outer edge of the open structure, thereby improving "single-sided heat dissipation" to "three-sided heat dissipation". At the same time, a second heat dissipation component with a toothed heat dissipation structure is arranged on the outer edge of the open structure, further enhancing the heat dissipation effect; (2) The heat sink and circuit board of the present invention are both modularly designed, so that the easily damaged heat-generating components and RF loads can be independently pulled out without opening the cover. The design is ingenious and replacement is more convenient; (3) A connector bracket is provided between the RF connector and the heat sink of the present invention, so that the lower part of the RF connector is fixedly connected to the heat sink, and the upper part is fixedly connected to the connector bracket. When the solid-state microwave source is assembled, the four fixing points of the RF connector can be installed at one time, which not only avoids the repeated work of melting the solder joints to release stress when the upper part of the RF connector is connected to the cover plate, but also eliminates the need to design the cover plate separately, so that the cover plate is improved to an integrated structure, which not only reduces the production cost, but also reduces the gap of the microwave source, reduces the radiation power value, and further avoids the leakage of microwaves, which has better safety performance for civilian scenarios; (4) The present invention innovatively uses flexible metal as an interface filler between the heat sink and the first heat dissipation component to replace thermal grease or thermal pads. While reaching or exceeding the thermal conductivity of the latter, it avoids the influence of the drying and aging phenomenon of the thermal grease and thermal pads caused by long-term use on the heat dissipation effect (generally, the life of a solid-state microwave source is about ten years, but the thermal grease and thermal pads will dry and age in the third year), greatly improving the maintenance-free service life of the solid-state microwave source.

[0016] In summary, the heat sink of the present invention is arranged on the surface of the heat dissipation component through an open "step" structure, which further enhances the heat dissipation effect, so that the fragile heat-generating components and RF loads can be independently withdrawn without opening the cover, making replacement more convenient, and avoiding the repeated work of secondary melting of solder joints to release stress. It also has better safety performance, maintenance-free and long service life, and is suitable for the generation of microwaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 A three-dimensional diagram of an embodiment of the present invention; Figure 2 An exploded view of an embodiment of the present invention; Figure 3 This is a three-dimensional diagram of a cover plate of an embodiment of the present invention when it is not shown; Figure 4 The figure is a schematic diagram of the installation of the radio frequency connector in the embodiment of the present invention.

[0019] In the figure: 1-first heat dissipation component, 2-installation step, 3-heat sink, 31-power amplifier matching heat sink, 32-RF load heat sink, 4-second heat dissipation component, 5-heating element, 6-RF load, 7-circuit board, 71-control board, 72-power amplifier matching circuit board, 73-RF load circuit board, 8-flexible metal, 9-RF connector, 91-connection hole, 92-connection line, 10-connector bracket, 101-avoidance groove, 11-ceramic strip line, 12-cover plate. DETAILED DESCRIPTION

[0020] The preferred embodiment of the present invention is described below in conjunction with the accompanying drawings. It should be understood that the solid-state microwave source described herein is a preferred embodiment, which is only used to illustrate and explain the present invention and does not constitute a limitation to the present invention.

[0021] The directional terms or positional relationships such as "up", "down", "left" and "right" described in the present invention are based on the directional relationships in the drawings of the present invention specification and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the content protected by the present invention. Example

[0022] In this embodiment, Figure 1-Figure 4 As shown, a solid-state microwave source includes a circuit board 7 and a radio frequency connector 9 connected to the circuit board 7. A heating element 5 is provided on the circuit board 7. The heating element 5 is connected to a first heat dissipation component 1 through a heat sink 3. A cover plate 12 is detachably connected to the side of the circuit board 7 away from the first heat dissipation component 1.

[0023] Specifically, the first heat dissipation component 1 in this embodiment is a cubic aluminum component, and a plurality of heat dissipation teeth arranged in parallel are formed at the lower end of the first heat dissipation component 1 to increase the heat dissipation area and improve the heat dissipation effect. Of course, the first heat dissipation component 1 can also be an alloy component. An installation step 2 is provided on the upper surface of the first heat dissipation component 1, and a heat sink 3 is arranged in the installation step 2.

[0024] The mounting step 2 is an open structure, extending to at least one side edge of the first heat dissipation component 1, that is, the mounting step 2 forms a plane lower than the upper surface of the first heat dissipation component 1, and the lower plane penetrates to at least one side edge of the first heat dissipation component 1. When the heat sink 3 is arranged in the mounting step 2, the side edge of the heat sink 3 can be exposed from the side edge of the first heat dissipation component 1. The solid-state microwave source in this embodiment is a symmetrical structure, and two mounting steps 2 are symmetrically arranged on the upper surface of the first heat dissipation component 1, and each mounting step 2 extends to the front edge and the corresponding left and right sides of the first heat dissipation component 1. Similarly, the heat sink 3 is also symmetrically arranged in the mounting step 2, and the specific shape of the mounting step 2 is adapted to the shape of the heat sink 3.

[0025] The heat sink 3 is preferably a copper plate. In the front-to-back direction, the size of the heat sink 3 is equal to the size of the mounting step 2, so that the front edge of the heat sink 3 is flush with the front edge of the first heat dissipation component 1. In the left-to-right direction, the size of the heat sink 3 is slightly smaller than the size of the mounting step 2. When the heat sink 3 is set in the mounting step 2, the left and right ends of the two heat sinks 3 will be retracted to the left and right edges of the first heat dissipation component 1. Inside the mounting step 2 and outside the left and right edges of the heat sink 3, a second heat dissipation component 4 for further heat dissipation is detachably fixed. The second heat dissipation component 4 is a strip structure, and a plurality of heat dissipation teeth arranged in parallel in the front-to-back direction are formed on the lower end surface. The size of the second heat dissipation component 4 in the front-to-back direction is adapted to the size of the heat sink 3 in the front-to-back direction, and the size in the left-to-right direction corresponds to the size of the heat sink 3 retracted in the first heat dissipation component 1, so that after the second heat dissipation component 4 is installed, it is flush with the left and right edges of the first heat dissipation component 1. With this arrangement, the original "single-sided heat dissipation" of the heat sink 3 to the first heat dissipation component 1 is improved to "three-sided heat dissipation" to the first heat dissipation component 1, the second heat dissipation component 4 on the left, and the second heat dissipation component 4 on the right, thereby further enhancing the heat dissipation effect.

[0026] The heating element 5 in this embodiment is a final-stage gallium nitride power amplifier tube, which is nested in the circuit board 7 and electrically connected to the circuit board 7. At the same time, the lower end surface of the final-stage gallium nitride power amplifier tube is fixedly mounted on the heat sink 3, so that the heat sink 3 can quickly conduct a large amount of heat emitted by the final-stage gallium nitride power amplifier tube. In order to facilitate the individual removal of the fragile final-stage gallium nitride power amplifier tube and the RF load 6 in the solid-state source, the circuit board 7 and the heat sink 3 in this embodiment are both modularly designed. Specifically, the circuit board 7 includes a disassembly plate that is fixedly connected to the heat sink 3 and flush with the outer edge of the heat sink 3, and a control board 71 that is fixedly connected to the first heat dissipation component 1, so that the heat sink 3, the disassembly plate and the heating component can be pulled out of the solid-state microwave source together. Furthermore, in order to remove the heating element 5 and the RF load 6 separately, the disassembly plate includes a power amplifier matching circuit board 72 for setting the final-stage gallium nitride power amplifier tube, and a RF load circuit board 73 for setting the RF load 6. The power amplifier matching circuit board 72 and the RF load circuit board 73 are independent of each other. Correspondingly, the heat sink 3 includes a power amplifier matching heat sink 31 flush with the power amplifier matching circuit board 72, and also includes a RF load heat sink 32 flush with the RF load circuit board 73. The power amplifier matching heat sink 31 and the RF load heat sink 32 are independent of each other, so that the power amplifier matching circuit board 72 and the power amplifier matching heat sink 31 can be pulled out from the solid-state microwave source together, and the RF load circuit board 73 and the RF load heat sink 32 can be pulled out from the solid-state microwave source together. The plug-in modular design is ingeniously conceived, which is not only convenient for production and installation, but also convenient for the individual replacement of vulnerable parts.

[0027] like Figure 2As shown, a flexible metal 8 is filled between the heat sink 3 and the first heat dissipation component 1 as an interface filler to replace thermal grease or thermal pad. The flexible metal 8 in this embodiment is a lead-free solder sheet with a model of SAC305 and a melting point of 217°C. While reaching or exceeding the thermal conductivity of the thermal grease or thermal pad, it avoids the influence of the long-term drying and aging of the thermal grease and the thermal pad on the heat dissipation effect, thereby greatly improving the maintenance-free service life of the solid-state microwave source.

[0028] The RF connector 9 extends through the heat sink 3 to the outer edge of the mounting step 2 and is connected to the circuit board 7. A connector bracket 10 is fixedly connected to the upper end of the outer edge of the heat sink 3. The heat sink 3 is provided with a first mounting hole that penetrates the heat sink 3 in the height direction. The lower end surface of the connector bracket 10 is provided with a second mounting hole (not shown in the figure) that matches the mounting hole. The connector bracket 10 is installed on the heat sink 3 by threaded fasteners. The end surface of the RF connector 9 used to connect to the solid-state microwave source is a rectangular plane, and a connecting hole 91 is provided at each of the four corners of the rectangular plane. The two connecting holes 91 at the lower part of the RF connector 9 are fixedly connected to the front end surface of the heat sink 3 by threaded fasteners, and the two connecting holes 91 at the upper part are fixedly connected to the front end surface of the connector bracket 10 by threaded fasteners. In the prior art, after the RF connector 9 is installed, its connecting wire 92 needs to be sintered together with the ceramic strip wire 11 of the circuit board 7. Therefore, the cover plate 12 is generally designed as a split structure, including a pressing frame and a closing plate on the top of the pressing frame. When installing the RF connector 9, the two connecting holes 91 below the RF connector 9 are first fixed to the front end surface of the heat sink 3 by threaded fasteners, and the pressing frame is installed on the first heat dissipation component 1. Since the pressing frame is a frame structure, the connecting wire 92 and the ceramic strip wire 11 of the RF connector 9 are exposed at this time. After the connecting wire 92 and the ceramic strip wire 11 of the RF connector 9 are sintered, the two connecting holes 91 on the upper part of the RF connector 9 are fixed to the pressing frame by threaded fasteners. However, when connecting the upper threaded fasteners, stress will appear between the two upper connection points and the two lower connection points. After all four connection points are connected, the solder joints of the connecting wire 92 and the ceramic strip wire 11 of the RF connector 9 need to be melted a second time to release the above stress. In this embodiment, Figure 4As shown, since the connector bracket 10 is provided and the connector bracket 10 is directly connected to the heat sink 3, when the RF connector 9 needs to be installed, the four connecting holes 91 of the RF connector 9 can be fixed at one time, and then the connecting wire 92 and the ceramic strip wire 11 can be sintered, thereby avoiding the work of secondary melting of the solder joint to release stress. Furthermore, an avoidance groove 101 is opened in the middle of the connector bracket 10 for connecting the RF connector 9 with the ceramic strip line 11 of the circuit board 7. The avoidance groove 101 is a through groove, which can be used to weld the RF connector 9 connecting line 92 and the ceramic strip line 11 when the connectors are installed. In this way, the cover plate 12 can be integrated into an integrated structure. A partition wall for dividing the cavity is provided on the side of the cover plate 12 facing the circuit board 7. When the RF connector 9 is connected to the heat sink 3 and the connector connecting block, the fixation is completed. The RF connector 9 connecting line 92 can be directly sintered on the ceramic strip line 11, and the cover plate 12 can be buckled separately, which not only reduces the production cost, but also reduces the gap of the microwave source, reduces the radiation power value, and further avoids the leakage of microwaves, which has better safety performance for civilian scenarios.

[0029] When assembling this embodiment, firstly, the heating element 5, the RF load 6 and other components are sintered and welded on the circuit board 7, the circuit board 7 is connected to the heat sink 3 by sintering or threaded fastening, the joint bracket 10 is placed and connected to the heat sink 3 by threaded fastening, the RF connector 9 is installed and the connecting wire 92 is welded, and finally, the flexible metal 8 is clamped between the heat sink 3 and the first heat dissipation component 1, and the heat sink 3 connected with the above components is connected to the first heat dissipation component 1 by threaded fastening. After the production test is completed, the second heat dissipation component 4 and the cover plate 12 with shielding glue applied are installed.

Claims

1. A solid-state microwave source, comprising a circuit board and a radio frequency connector connected to the circuit board, a heating element is provided on the circuit board, the heating element is connected to a first heat dissipation component through a heat sink, and a cover plate is detachably connected to a side of the circuit board away from the first heat dissipation component, characterized in that: The surface of the first heat dissipation component is provided with an installation step, which extends to at least one side edge of the first heat dissipation component. The heat sink is arranged in the installation step, and a second heat dissipation component is fixedly connected inside the installation step and outside the side edge of the heat sink.

2. A solid-state microwave source according to claim 1, characterized in that: The second heat dissipation component is adapted to the side edge size of the heat sink, and a tooth-shaped heat dissipation structure is formed on the second heat dissipation component.

3. A solid-state microwave source according to claim 2, characterized in that: The mounting step extends to two adjacent outer edges of the first heat dissipation component, the second heat dissipation component is fixed at one of the outer edges of the mounting step, and the edge of the heat sink extends to the other outer edge of the mounting step; The circuit board comprises a disassembly plate fixedly connected to the heat sink and flush with the outer edge of the heat sink, and a control board fixedly connected to the first heat dissipation component, so that the heat sink, the disassembly plate and the heat-generating component can be withdrawn from the solid-state microwave source together.

4. A solid-state microwave source according to claim 3, characterized in that: The disassembly version includes a power amplifier matching circuit board for setting a heating element, and also includes a radio frequency load circuit board for setting a radio frequency load, and the power amplifier matching circuit board and the radio frequency load circuit board are independent of each other; the heat sink includes a power amplifier matching heat sink flush with the power amplifier matching circuit board, and also includes a radio frequency load heat sink flush with the radio frequency load circuit board, and the power amplifier matching heat sink and the radio frequency load heat sink are independent of each other, so that the power amplifier matching circuit board and the power amplifier matching heat sink can be pulled out from the solid-state microwave source together, and the radio frequency load circuit board and the radio frequency load heat sink can be pulled out from the solid-state microwave source together.

5. A solid-state microwave source according to claim 4, characterized in that: The radio frequency connector is extended to the outer edge of the mounting step through the heat sink and connected to the circuit board.

6. A solid-state microwave source according to claim 1, characterized in that: Flexible metal is filled between the heat sink and the first heat dissipation component.

7. A solid-state microwave source according to any one of claims 1 to 6, characterized in that: The edge of the heat sink is fixedly connected with a joint bracket, so that the lower part of the radio frequency connector is fixedly connected to the heat sink, and the upper part is fixedly connected to the joint bracket.

8. A solid-state microwave source according to claim 7, characterized in that: The connector bracket is provided with an avoidance groove for connecting the radio frequency connector with the ceramic strip line of the circuit board.

9. A solid-state microwave source according to claim 8, characterized in that: The cover plate is an integrated cover plate, and a partition wall for dividing the cavity is arranged on one side of the cover plate facing the circuit board.

10. A solid-state microwave source according to claim 1, characterized in that: The heat sink is a copper plate.

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