Electric stirring solid microwave heating device

Abstract

An electrically-stirred solid-state microwave heating device comprises a solid-state microwave source, microwaves generated by the solid-state microwave source are radiated into a heating cavity or a heating space through an antenna array, an antenna housing is arranged between the antenna array and the heating cavity or the heating space, and a metal heat dissipation plate is attached to the side, away from the antenna housing, of the solid-state microwave source. A heat dissipation air channel is further arranged between the solid-state microwave source and the metal heat dissipation plate. Multiple paths of microwave signals with adjustable frequencies, amplitudes and phases are generated through a solid-state microwave source and are fed into an antenna array, electromagnetic energy of multiple branches is synthesized in space, different radiation states are generated according to control signals, and the heating effect of electric stirring is achieved; the metal heat dissipation plate and the heat dissipation air channel can timely dissipate heat generated by loss of the solid-state microwave source; electromagnetic energy radiated by the antenna array passes through the antenna housing, and the antenna housing can package the antenna array. The device has the advantages of being uniform in heating, good in heat dissipation performance, compact in structure and high in cleanliness.

Description

Technical Field

[0001] The invention relates to the technical field of microwave heating, in particular to an electrically stirred solid-state microwave heating device. Background Art

[0002] Microwave heating is a method of heating objects by electromagnetic fields. Microwaves can penetrate objects and produce thermal effects inside them, heating the inside of the object evenly, avoiding the problem of the surface being easily burnt and the inside being undercooked in traditional heating methods. It has a wide range of applications in household and industrial heating fields.

[0003] In the current common microwave heating systems, magnetrons are mostly used as microwave energy generators. After the energy is coupled into the waveguide, it is transmitted and fed into the metal cavity to heat the object in the cavity. The magnetron is a large-volume vacuum device that occupies a large space and requires a high-voltage working power supply, and has high requirements for heat dissipation. With the development of high-power semiconductor devices such as GaN, solid-state microwave circuits have replaced traditional magnetrons in many fields due to their small size, long life, easy control, and no need for high-voltage power supply. For example, in radar systems, the previous magnetron feed source is now mostly replaced by a solid-state microwave source. Using solid-state microwave sources as feed sources for heating systems is an important development direction in the future.

[0004] According to electromagnetic field theory, the electromagnetic field in a metal cavity has a fixed resonance mode, which causes the electromagnetic field to be unevenly distributed in space, which is not conducive to uniform heating. Therefore, current household microwave heating systems mostly use mechanical stirring. One type is to place the food on a turntable so that the food is evenly heated during rotation, but this method requires a large space in the cavity, and the oil generated during the heating process easily leaks into the microwave feed port, making it difficult to clean. Another mechanical stirring method is to place the stirrer under the glass partition of the food, and improve the heating uniformity by changing the electromagnetic field resonance distribution in the cavity, but it still has the disadvantages of being large in size and easy to ignite. Using multiple feed sources is another way to improve the uniformity of the electromagnetic field in the cavity, but due to the lack of active stirring, the heating uniformity of this method is not optimistic.

[0005] Wang Zhuangfei (Wang Zhuangfei, Xu Dongyuan, Huang Jie, et al. Application of variable frequency phase-modulated power-dividing feeding network in microwave directional heating [J]. Vacuum Electronics Technology, 2022, (02): 77-81. DOI: 10.16540 / j.cnki.cn11-2485 / tn.2022.02.12.) proposed a microwave directional heating method based on a variable frequency phase-modulated power-dividing feeding network. By changing the frequency of the solid-state microwave source, the phase of the radiating antenna unit is indirectly changed to achieve the change of the radiation energy direction, and a good heating and stirring effect is achieved in the three-zone heating system in the cavity; however, this method can only control the frequency of the solid-state microwave source, and the control method is limited. The control ability for the multi-antenna system is limited. At the same time, due to the large power of the single solid-state microwave source and the inconsistent phase on the power-dividing network, there will be a large power loss on the isolation resistor. Summary of the invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide an electrically stirred solid-state microwave heating device, which generates multi-channel microwave signals with adjustable frequency, amplitude and phase through a solid-state microwave source, and feeds them into an antenna array. The electromagnetic energy of multiple branches is synthesized in space, and different radiation states are generated according to the control signal to achieve the heating effect of electrical stirring; the metal heat sink and the heat dissipation duct can dissipate the heat generated by the loss of the solid-state microwave source in time; the electromagnetic energy radiated by the antenna array passes through the antenna cover, and the antenna cover can also encapsulate the antenna array; the device has the characteristics of uniform heating, good heat dissipation, compact structure and high cleanliness, and can be widely used in technical fields such as microwave heating.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] An electrically stirred solid-state microwave heating device comprises a solid-state microwave source 3, wherein the solid-state microwave source 3 generates microwaves which are radiated into a heating cavity or a heating space through an antenna array 2, an antenna cover 1 is arranged between the antenna array 2 and the heating cavity or the heating space, a metal heat sink 5 is attached to a side of the solid-state microwave source 3 which is away from the antenna cover 1, and a heat dissipation duct 4 is also arranged between the solid-state microwave source 3 and the metal heat sink 5.

[0009] Furthermore, the antenna array 2 includes an antenna unit 21 , a feeding probe 22 and an antenna ground plane 23 ; the feeding probe 22 is connected to the antenna unit 21 through the antenna ground plane 23 ; and the antenna unit 21 is connected to the solid-state microwave source 3 through the feeding probe 22 .

[0010] Furthermore, the solid-state microwave source 3 includes a frequency synthesis module 31, a feeding network module 32, multiple solid-state power amplifier modules 33 and a control circuit 34; the signal output end of the frequency synthesis module 31 is connected to the signal input end of the feeding network module 32, the signal output end of the feeding network module 32 is respectively connected to the signal input end of the multiple solid-state power amplifier modules 33, and the control circuit 34 is respectively signal-connected to the frequency synthesis module 31, the feeding network module 32, and the multiple solid-state power amplifier modules 33.

[0011] Furthermore, the frequency synthesis module 31 includes an integrated phase-locked loop chip 311 and a preliminary amplifying circuit 312; the signal output end of the integrated phase-locked loop chip 311 is connected to the signal input end of the preliminary amplifying circuit 312;

[0012] The feed network module 32 includes a power divider 321 and a plurality of phase shifters 322; the signal output end of the preliminary amplification circuit 312 is connected to the signal input end of the power divider 321, and the signal output end of the power divider 321 is respectively connected to the signal input ends of the plurality of phase shifters 322;

[0013] The solid-state power amplifier module 33 includes an adjustable attenuator 331, a primary power amplifier 332 and a secondary power amplifier 333; the signal output end of the phase shifter 322 is connected to the signal input end of the adjustable attenuator 331, the signal output end of the adjustable attenuator 331 is connected to the signal input end of the primary power amplifier 332, and the signal output end of the primary power amplifier 332 is connected to the signal input end of the secondary power amplifier 333;

[0014] The control circuit 34 is respectively connected to the integrated phase-locked loop chip 311 , the plurality of phase shifters 322 , and the plurality of adjustable attenuators 331 in phase signal connection.

[0015] Furthermore, the antenna array 2 uses multiple antenna units 21 arranged in a phased array manner, including but not limited to a linear array, a planar array or a curved array layout.

[0016] Furthermore, the antenna unit 21 adopts a patch antenna or a suspended plate antenna, and the operating frequency band is 2400-2500 MHz.

[0017] Furthermore, the input reflection coefficient of the antenna array 2 is less than -10 dB within the operating frequency band.

[0018] Furthermore, the control circuit 34 includes a single chip microcomputer for controlling the working state of the solid-state microwave source 3 .

[0019] Furthermore, the primary power amplifier 332 and the secondary power amplifier 333 are constructed using semiconductor devices; the semiconductor devices include but are not limited to GaN semiconductor devices.

[0020] Furthermore, the antenna array 2 and the solid-state microwave source 3 are integrated into one by using a PCB process.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention adopts a solid-state microwave source 3 to replace the traditional magnetron feed source. Under the premise of multi-channel energy feeding, a circuit is used to control the state of energy in different channels, and different electromagnetic field distributions are synthesized in the heating cavity or heating space to achieve electric stirring. While improving the heating uniformity, the volume occupied by the equipment can be reduced, thereby increasing the service life of the equipment. In addition, by replacing a single magnetron with multiple solid-state power amplifier modules 33, a large heat source is replaced with multiple small heat sources, which can achieve distributed heat dissipation and reduce heat dissipation pressure.

[0023] 2. The present invention combines multiple antenna arrays 2 and multiple solid-state microwave sources 3 to replace traditional mechanical stirring. The amplitude, phase, and frequency of microwave energy are controlled by the control circuit 34 to change the radiation energy state, thereby realizing electric stirring of microwave heating and reducing the problems of ignition and oil cleaning.

[0024] 3. The antenna array 2 and the solid-state microwave source 3 can be integrated into one, and the whole board can be realized by mature PCB technology, with a compact structure, which significantly reduces the volume and weight of the whole system and is easy to disassemble, assemble and replace.

[0025] In summary, the present invention uses phased array antenna scanning technology for microwave heating, generates multi-channel microwave signals with adjustable frequency, amplitude and phase through a solid-state microwave source 3, and feeds them into the antenna array 2. The electromagnetic energy of multiple branches is synthesized in space, and different radiation states are generated according to the control signal to achieve the heating effect of electric stirring. Compared with traditional mechanical stirring, it improves the heating uniformity while avoiding problems such as sparks; by designing a metal heat sink 5 and a heat dissipation duct 4, the heat generated by the loss of the solid-state microwave source 3 can be dissipated in time. At the same time, due to the distributed operation of multiple solid-state power amplifier modules 33, the heat dissipation pressure of a single tube is reduced, and it can be widely used in technical fields such as microwave heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the electrically stirred solid-state microwave heating device of the present invention.

[0027] Figure 2 It is the appearance diagram of the antenna array 2 in the present invention.

[0028] Figure 3 It is a schematic diagram of the structure of the solid-state microwave source 3 in the present invention.

[0029] Figure 4 This is the radiation gain state 1 of the antenna array 2 in the present invention.

[0030] Figure 5 This is the radiation gain state 2 of the antenna array 2 in the present invention.

[0031] Figure 6 is the input reflection coefficient of the antenna array 2 in the present invention.

[0032] In the figure: 1. Radome; 2. Antenna array; 21. Antenna unit; 22. Feed probe; 23. Antenna ground plane; 3. Solid-state microwave source; 31. Frequency synthesis module; 311. Integrated phase-locked loop chip; 312. Preliminary amplification circuit; 32. Feed network module; 321. Power divider; 322. Phase shifter; 33. Solid-state power amplifier module; 331. Adjustable attenuator; 332. Primary power amplifier; 333. Secondary power amplifier; 34. Control circuit; 4. Heat dissipation duct; 5. Metal heat sink. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0034] See also Figure 1 , an electrically stirred solid-state microwave heating device, comprising a solid-state microwave source 3, wherein the solid-state microwave source 3 generates microwaves which are radiated into a heating cavity or a heating space through an antenna array 2, an antenna cover 1 is arranged between the antenna array 2 and the heating cavity or the heating space, a metal heat sink 5 is attached to the side of the solid-state microwave source 3 facing away from the antenna cover 1, and a heat dissipation duct 4 is also arranged between the solid-state microwave source 3 and the metal heat sink 5.

[0035] This embodiment aims to replace the traditional magnetron with a solid-state microwave source 3, and replace the traditional mechanical stirring with electric stirring to improve the heating effect. The solid-state microwave source 3 generates multi-channel microwave energy, and changes the amplitude, phase, and frequency of the energy fed into the antenna array 2 through the control circuit 34 of the solid-state microwave source 3 itself. According to the phased array antenna theory, the energy radiated by multiple antennas will be synthesized in the heating cavity or space, generating different microwave energy radiation directions and states, thereby realizing the electric stirring of the electromagnetic energy of the heating cavity or heating space; the antenna cover 1 is installed between the antenna array 2 and the heating cavity or heating space, and the electromagnetic energy radiated by the antenna array 2 can pass through the antenna cover 1 normally, and the antenna cover 1 can encapsulate the antenna array 2. The solid-state microwave source 3 is connected to the metal heat sink 5 by heat dissipation silicone grease, and the heat of the solid-state microwave source is timely introduced into the metal heat sink 5, and a heat dissipation duct 4 is provided between the solid-state microwave source 3 and the metal heat sink 5, which can timely take away the heat generated by the loss of the solid-state microwave source 3, thereby realizing the encapsulation and heat dissipation of the entire device.

[0036] like Figure 2The antenna array 2 includes an antenna unit 21 , a feeding probe 22 and an antenna ground plane 23 ; the feeding probe 22 is connected to the antenna unit 21 through the antenna ground plane 23 ; and the antenna unit 21 is connected to the solid-state microwave source 3 through the feeding probe 22 .

[0037] The antenna array 2 uses multiple antenna units 21 arranged in a phased array manner, including but not limited to a linear array, a planar array or a curved array layout.

[0038] The antenna units 21 of this embodiment are arranged in a 4*4 planar array, which can perform radiation scanning in a two-dimensional direction and effectively reduce the heat dissipation pressure of a single solid-state power amplifier module. The unit spacing is 0.5 wavelengths, which belongs to the normal phased array antenna unit layout spacing (in order to avoid grating lobes, the general spacing is less than or equal to 0.5 wavelengths); the feeding probe 22 passes through the antenna ground plane 23 and feeds the antenna unit 21, and the solid-state microwave source 3 is connected to the antenna array 2 through the feeding probe 22. The antenna array 2 radiates the microwaves generated by the solid-state microwave source 3 to the heating cavity or heating space, and synthesizes electromagnetic energy in the space, thereby realizing electric stirring of microwave heating.

[0039] The antenna unit 21 adopts a patch antenna or a suspended plate antenna, and selects an S-band operating frequency band of 2400-2500 MHz.

[0040] like Figure 3 As shown, the solid-state microwave source 3 includes a frequency synthesis module 31, a feeding network module 32, a plurality of solid-state power amplifier modules 33 and a control circuit 34; the signal output end of the frequency synthesis module 31 is connected to the signal input end of the feeding network module 32, the signal output end of the feeding network module 32 is respectively connected to the signal input end of the plurality of solid-state power amplifier modules 33, and the control circuit 34 is respectively signal-connected to the frequency synthesis module 31, the feeding network module 32, and the plurality of solid-state power amplifier modules 33.

[0041] In this embodiment, the frequency synthesis module 31 generates microwave energy and feeds it into the feeding network module 32. The feeding network module 32 divides the microwave energy into multiple microwave energies and connects them to the solid-state power amplifier module 33. The solid-state power amplifier module 33 amplifies the multiple microwave energies. The control circuit 34 is respectively connected to the frequency synthesis module 31, the feeding network module 32, and the solid-state power amplifier module 33, and is used to control the working state of the entire solid-state microwave source 3.

[0042] The frequency synthesis module 31 includes an integrated phase-locked loop chip 311 and a preliminary amplifying circuit 312; the signal output end of the integrated phase-locked loop chip 311 is connected to the signal input end of the preliminary amplifying circuit 312; the integrated phase-locked loop chip 311 generates microwave energy according to the signal sent by the control circuit 34, and the preliminary amplifying circuit 312 performs preliminary amplification on the microwave energy.

[0043] The feed network module 32 includes a power divider 321 and a plurality of phase shifters 322; the signal output end of the preliminary amplification circuit 312 is connected to the signal input end of the power divider 321, and the signal output end of the power divider 321 is respectively connected to the signal input ends of the plurality of phase shifters 322;

[0044] The power divider 321 of this embodiment is a 1-to-16 power divider. The types of the power divider 321 include but are not limited to Wilkinson power dividers. Gysel power dividers and T-type power dividers can all be used as the power divider of this embodiment. The branch structure of the power divider 321 includes but is not limited to an equal-division structure and an unequal-division structure. Both a one-to-two and a one-to-many-path structure can be used as the branch structure of the power divider 321 of this embodiment. The routing form of the power divider 321 includes but is not limited to a microstrip line, a strip line, and a grounded coplanar waveguide form. After receiving the microwave energy preliminarily amplified by the preliminary amplification circuit 312, the power divider 321 divides the input single-path microwave energy into 16 paths, and changes the phase of the 16 paths of microwave energy through the phase shifter 322 added at the end of each branch of the power divider 321.

[0045] The solid-state power amplifier module 33 includes an adjustable attenuator 331, a first-stage power amplifier 332 and a second-stage power amplifier 333; the signal output end of the phase shifter 322 is connected to the signal input end of the adjustable attenuator 331, the signal output end of the adjustable attenuator 331 is connected to the signal input end of the first-stage power amplifier 332, and the signal output end of the first-stage power amplifier 332 is connected to the signal input end of the second-stage power amplifier 333.

[0046] The solid-state power amplifier module 33 of this embodiment includes a two-stage power amplifier and an adjustable attenuator 331. After receiving the microwave signal with changed phase, the adjustable attenuator 331 adjusts the output power of the microwave signal according to the signal sent by the control circuit 34, and transmits it to the first-stage power amplifier 332 and the second-stage power amplifier 333 in sequence to further amplify the microwave signal.

[0047] The control circuit 34 is respectively connected to the integrated phase-locked loop chip 311, the multiple phase shifters 322 and the adjustable attenuator 331 by phase signals. The control circuit 34 is connected to the integrated phase-locked loop chip 311 by phase signals to control the frequency and power of the main signal output by the integrated phase-locked loop chip 311; the control circuit 34 is connected to the phase shifter 322 by phase signals to control the phase of each branch microwave energy; the control circuit 34 is connected to the adjustable attenuator 331 by phase signals to control the amplitude of each branch microwave energy.

[0048] The control circuit 34 includes a single chip microcomputer, which is used to control the working state of the solid-state microwave source 3. The control signal line of the single chip microcomputer is connected to the control pins of the integrated phase-locked loop chip 311, the phase shifter 322 and the adjustable attenuator 331 inside the solid-state microwave source 3, and the serial communication protocol is used to control the working state of the chip.

[0049] The primary power amplifier 332 and the secondary power amplifier 333 are constructed using semiconductor devices; the semiconductor devices include but are not limited to GaN semiconductor devices, LDMOS semiconductor devices, GaAs semiconductor devices, and SiGe semiconductor devices can all be used as semiconductor devices in this embodiment.

[0050] The antenna array 2 and the solid-state microwave source 3 are integrated into one body through PCB technology, and have a compact structure, which significantly reduces the volume and weight of the entire system and facilitates disassembly, assembly and replacement.

[0051] In order to control the amplitude, phase, and frequency of the radiated energy fed into each antenna, two different radiation states are synthesized in space; Figure 4 It is the radiation gain state 1, and the maximum radiation direction is located in the normal direction of the antenna array; Figure 5 It is the radiation gain state two, the maximum radiation direction is below the normal, the electromagnetic field distribution of the heating cavity or space changes, and the heating area changes according to the control signal.

[0052] like Figure 6 As shown, the input reflection coefficient of the antenna array 2 is less than -10dB within the working frequency band, so that most of the electromagnetic energy can be radiated into the heating cavity or space, which can meet the normal working requirements of the entire heating device.

[0053] The working principle of the present invention is:

[0054] Phased array antenna scanning technology is used for microwave heating. First, a solid-state microwave source 3 is used to generate multi-channel microwave signals with adjustable frequency, amplitude and phase, and the signals are fed into the antenna array 2. The electromagnetic energy of multiple branches is synthesized in space, and different radiation states are generated according to the control signal to achieve an electric stirring heating effect. An antenna cover 1 is installed between the antenna array 2 and the heating cavity or heating space. The electromagnetic energy radiated by the antenna array 2 can pass through the antenna cover 1 normally, and the antenna cover 1 can encapsulate the antenna array 2. The heat generated by the loss of the solid-state microwave source 3 is dissipated in time by designing a metal heat sink 5 and a heat dissipation duct 4. At the same time, multiple solid-state power amplifier modules 33 are used to work in a distributed manner to reduce the heat dissipation pressure of a single tube.

[0055] The above embodiments are merely detailed descriptions of the present invention, but the present invention is not limited to the above embodiments. Any modifications, substitutions and changes made to the present invention within the spirit of the present invention and the protection scope of the claims are within the protection scope of the present invention.

Claims

1. An electrically stirred solid-state microwave heating device, characterized in that: The invention comprises a solid-state microwave source (3), wherein the solid-state microwave source (3) generates microwaves which are radiated into a heating cavity or a heating space through an antenna array (2), an antenna cover (1) is arranged between the antenna array (2) and the heating cavity or the heating space, a metal heat dissipation plate (5) is attached to a side of the solid-state microwave source (3) facing away from the antenna cover (1), and a heat dissipation duct (4) is also arranged between the solid-state microwave source (3) and the metal heat dissipation plate (5).

2. The electrically stirred solid-state microwave heating device according to claim 1, characterized in that: The antenna array (2) comprises an antenna unit (21), a feeding probe (22) and an antenna ground plane (23); the feeding probe (22) passes through the antenna ground plane (23) to be connected to the antenna unit (21); and the antenna unit (21) is connected to a solid-state microwave source (3) via the feeding probe (22).

3. An electrically stirred solid-state microwave heating device according to claim 1 or 2, characterized in that: The solid-state microwave source (3) comprises a frequency synthesizer module (31), a feed network module (32), a plurality of solid-state power amplifier modules (33) and a control circuit (34); the signal output end of the frequency synthesizer module (31) is connected to the signal input end of the feed network module (32), the signal output end of the feed network module (32) is respectively connected to the signal input ends of the plurality of solid-state power amplifier modules (33), and the control circuit (34) is respectively signal-connected to the frequency synthesizer module (31), the feed network module (32) and the plurality of solid-state power amplifier modules (33).

4. The electrically stirred solid-state microwave heating device according to claim 3, characterized in that: The frequency synthesizer module (31) comprises an integrated phase-locked loop chip (311) and a preliminary amplifying circuit (312); the signal output end of the integrated phase-locked loop chip (311) is connected to the signal input end of the preliminary amplifying circuit (312); The feed network module (32) comprises a power divider (321) and a plurality of phase shifters (322); the signal output end of the preliminary amplification circuit (312) is connected to the signal input end of the power divider (321), and the signal output end of the power divider (321) is respectively connected to the signal input ends of the plurality of phase shifters (322); The solid-state power amplifier module (33) comprises an adjustable attenuator (331), a primary power amplifier (332) and a secondary power amplifier (333); the signal output end of the phase shifter (322) is connected to the signal input end of the adjustable attenuator (331), the signal output end of the adjustable attenuator (331) is connected to the signal input end of the primary power amplifier (332), and the signal output end of the primary power amplifier (332) is connected to the signal input end of the secondary power amplifier (333); The control circuit (34) is respectively connected to the integrated phase-locked loop chip (311), a plurality of phase shifters (322) and a plurality of adjustable attenuators (331) in phase signal communication.

5. The electrically stirred solid-state microwave heating device according to claim 2, characterized in that: The antenna array (2) uses a plurality of antenna units (21) arranged in a phased array manner, including but not limited to a linear array, a planar array or a curved array layout.

6. An electrically stirred solid-state microwave heating device according to claim 2 or 5, characterized in that: The antenna unit (21) adopts a patch antenna or a suspended plate antenna, and the operating frequency band is 2400-2500 MHz.

7. The electrically stirred solid-state microwave heating device according to claim 1, characterized in that: The input reflection coefficient of the antenna array (2) is less than -10 dB within the working frequency band.

8. The electrically stirred solid-state microwave heating device according to claim 4, characterized in that: The control circuit (34) comprises a single chip microcomputer, and is used to control the working state of the solid-state microwave source (3).

9. The electrically stirred solid-state microwave heating device according to claim 4, characterized in that: The primary power amplifier (332) and the secondary power amplifier (333) are constructed using semiconductor devices; the semiconductor devices include but are not limited to GaN semiconductor devices.

10. The electrically stirred solid-state microwave heating device according to claim 1, characterized in that: The antenna array (2) and the solid-state microwave source (3) are integrated into one body through a PCB process.

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