阅读说明：本技术 控制方法和微波烹饪设备 (Control method and microwave cooking equipment ) 是由 方友平 吴添洪 陈茂顺 唐相伟 于 2020-06-30 设计创作，主要内容包括：本发明提供了一种控制方法和微波烹饪设备。微波烹饪设备包括微波源、放大器和天线。放大器连接微波源和天线,微波源包括数字信号链路单元。控制方法包括：对数字信号链路单元产生的中频信号进行预失真处理,以使得输入放大器的微波信号在谐波频段相位与放大器输出的微波信号的相位相反且幅度相同,进而抵消放大器产生的高次谐波。上述控制方法中,预失真处理可在设计阶段进行仿真,指导实际设计,抑制度可量化设计,预失真处理算法无需增加硬件成本,对有用信号功率造成损失的较小。(The invention provides a control method and microwave cooking equipment. The microwave cooking apparatus includes a microwave source, an amplifier, and an antenna. The amplifier is connected with the microwave source and the antenna, and the microwave source comprises a digital signal link unit. The control method comprises the following steps: the intermediate frequency signal generated by the digital signal link unit is subjected to predistortion treatment, so that the phase of the microwave signal input into the amplifier is opposite to that of the microwave signal output by the amplifier in the harmonic frequency band, and the amplitude of the microwave signal is the same, and then the higher harmonic generated by the amplifier is counteracted. In the control method, the predistortion treatment can be simulated in the design stage to guide the actual design, the suppression degree can be quantitatively designed, the predistortion treatment algorithm does not need to increase the hardware cost, and the loss of the useful signal power is less.)

1. A control method for a microwave cooking apparatus, the microwave cooking apparatus comprising a microwave source, an amplifier and an antenna, the amplifier connecting the microwave source and the antenna, the microwave source comprising a digital signal link unit, the control method comprising:

and pre-distortion processing is carried out on the intermediate frequency signal generated by the digital signal link unit, so that the phase of the microwave signal input into the amplifier in a harmonic frequency band is opposite to that of the microwave signal output by the amplifier in phase and has the same amplitude, and the higher harmonic generated by the amplifier is further counteracted.

2. The control method of claim 1, wherein the microwave source comprises a microwave signal generator, the control method comprising:

performing digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal;

mixing the analog intermediate frequency signal with a microwave signal generated by the microwave signal generator and generating a microwave signal input to the amplifier.

3. The control method according to claim 1, wherein the microwave cooking apparatus includes a coupler and a detector, the coupler connects the amplifier and the antenna, the detector connects the coupler, the control method includes:

and controlling the operation of the microwave source according to the electric signal output by the detector.

4. The control method of claim 3, wherein controlling the operation of the microwave source based on the electrical signal output by the detector comprises: and determining whether the amplitude of the signal output by the digital signal link unit needs to be adjusted or determining whether the gain of the amplifier needs to be adjusted or determining whether the amplitude of the signal output by the digital signal link unit needs to be adjusted and the gain of the amplifier needs to be adjusted according to the electric signal output by the detector.

5. The control method according to claim 1, wherein the microwave cooking apparatus includes a filter connecting an output of the amplifier and the antenna.

6. The microwave cooking equipment is characterized by comprising a microwave source, an amplifier, an antenna and a processor, wherein the processor is connected with the microwave source, the amplifier is connected with the microwave source and the antenna, the microwave source comprises a digital signal link unit, and the processor is used for carrying out pre-distortion processing on an intermediate frequency signal generated by the digital signal link unit, so that the phase of the microwave signal input into the amplifier is opposite to that of the microwave signal output by the amplifier in a harmonic frequency band, and the amplitude of the microwave signal is the same, and further, higher harmonics generated by the amplifier are counteracted.

7. Microwave cooking device according to claim 6, characterized in that the microwave source comprises a microwave signal generator, a digital-to-analog converter and a mixer, the digital-to-analog converter being connected to the digital signal link unit and the mixer, the mixer being connected to the microwave signal generator,

the digital-to-analog converter is used for performing digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal;

the mixer is used for mixing the analog intermediate frequency signal with the microwave signal generated by the microwave signal generator and generating a microwave signal which is input to the amplifier.

8. A microwave cooking apparatus according to claim 6, wherein the microwave cooking apparatus includes a coupler and a detector, the coupler being connected to the amplifier and the antenna, the detector being connected to the coupler, the processor being configured to control operation of the microwave source in dependence on an electrical signal output by the detector.

9. The microwave cooking apparatus according to claim 8, wherein the processor is configured to determine whether the amplitude of the signal output from the digital signal link unit needs to be adjusted, or determine whether the gain of the amplifier needs to be adjusted, or determine whether the amplitude of the signal output from the digital signal link unit needs to be adjusted and the gain of the amplifier needs to be adjusted, based on the electrical signal output from the detector.

10. Microwave cooking device according to claim 6, characterized in that it comprises a filter connecting the output of the amplifier and the antenna.

Technical Field

The invention relates to the field of microwave heating, in particular to a control method and microwave cooking equipment.

Background

In the related art, electronic and household electrical products need to meet EMC test requirements, and household electrical products applying microwave signals in ISM frequency band need to meet the conventional limit value of 30 MHz-1 GHz and the limit value requirement of higher harmonic. The conventional method for inhibiting the higher harmonics of the microwave source comprises the first step of adjusting the structural size of the door teeth on the oven door to strengthen the microwave leakage inhibition, the second step of strengthening the shell grounding of the whole machine to improve the microwave inhibition degree of the shell, and the third step of adjusting the input-output matching circuit of the final amplifier in the microwave source to reduce the output amplitude of the harmonics.

However, the first method and the second method need to adjust the structural design of the whole machine, a large number of test tests and verifications are needed, and different platforms and models have no reproducibility, so that the method belongs to blind tuning optimization. In the third method, by adjusting an input-output matching circuit of a final amplifier in the microwave source, the useful signal power and efficiency are also deteriorated while the harmonic amplitude is suppressed, and compromise treatment needs to be balanced on three parameters of the harmonic amplitude, the output power and the module efficiency.

Disclosure of Invention

The embodiment of the invention provides a control method and microwave cooking equipment.

The control method of the embodiment of the invention is used for microwave cooking equipment, the microwave cooking equipment comprises a microwave source, an amplifier and an antenna, the amplifier is connected with the microwave source and the antenna, the microwave source comprises a digital signal link unit, and the control method comprises the following steps: and pre-distortion processing is carried out on the intermediate frequency signal generated by the digital signal link unit, so that the phase of the microwave signal input into the amplifier in a harmonic frequency band is opposite to that of the microwave signal output by the amplifier in phase and has the same amplitude, and the higher harmonic generated by the amplifier is further counteracted.

In the control method, the predistortion treatment can be simulated in the design stage to guide the actual design, the suppression degree can be quantitatively designed, the predistortion treatment algorithm does not need to increase the hardware cost, and the loss of the useful signal power is less.

In some embodiments, the microwave source comprises a microwave signal generator, and the control method comprises: performing digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal; mixing the analog intermediate frequency signal with a microwave signal generated by the microwave signal generator and generating a microwave signal input to the amplifier.

In some embodiments, the microwave cooking apparatus includes a coupler and a detector, the coupler connects the amplifier and the antenna, the detector connects the coupler, the control method includes: and controlling the operation of the microwave source according to the electric signal output by the detector.

In some embodiments, controlling the operation of the microwave source in response to the electrical signal output by the detector comprises: and determining whether the amplitude of the signal output by the digital signal link unit needs to be adjusted or determining whether the gain of the amplifier needs to be adjusted or determining whether the amplitude of the signal output by the digital signal link unit needs to be adjusted and the gain of the amplifier needs to be adjusted according to the electric signal output by the detector.

In some embodiments, the microwave cooking apparatus includes a filter connecting the output of the amplifier and the antenna.

The microwave cooking equipment comprises a microwave source, an amplifier, an antenna and a processor. The processor is connected with the microwave source, the amplifier is connected with the microwave source and the antenna, and the microwave source comprises a digital signal link unit. The processor is used for carrying out pre-distortion processing on the intermediate frequency signals generated by the digital signal link unit, so that the phases of the microwave signals input into the amplifier in a harmonic frequency band are opposite to the phases of the microwave signals output by the amplifier and have the same amplitude, and further, higher harmonics generated by the amplifier are counteracted.

In the microwave cooking equipment, the predistortion treatment can be simulated in the design stage to guide the actual design, the suppression degree can be quantitatively designed, the predistortion treatment algorithm does not need to increase the hardware cost, and the loss of the useful signal power is small.

In some embodiments, the microwave source includes a microwave signal generator, a digital-to-analog converter and a mixer, the digital-to-analog converter is connected to the digital signal link unit and the mixer, the mixer is connected to the microwave signal generator, and the digital-to-analog converter is configured to perform digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal; the mixer is used for mixing the analog intermediate frequency signal with the microwave signal generated by the microwave signal generator and generating a microwave signal which is input to the amplifier.

In some embodiments, the microwave cooking device comprises a coupler and a detector, the coupler is connected with the amplifier and the antenna, the detector is connected with the coupler, and the processor is used for controlling the operation of the microwave source according to an electric signal output by the detector.

In some embodiments, the processor is configured to determine whether an adjustment of the amplitude of the signal output by the digital signal link unit is required, or determine whether an adjustment of the gain of the amplifier is required, or determine whether an adjustment of the amplitude of the signal output by the digital signal link unit and an adjustment of the gain of the amplifier are required, based on the electrical signal output by the detector.

In some embodiments, the microwave cooking apparatus includes a filter connecting the output of the amplifier and the antenna.

Additional aspects and advantages of embodiments of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the present application.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic block diagram of a microwave cooking apparatus according to an embodiment of the present invention;

fig. 2 to 4 are frequency spectrum diagrams of a microwave cooking apparatus according to an embodiment of the present invention;

fig. 5 to 6 are block schematic views of a microwave cooking apparatus according to an embodiment of the present invention;

FIG. 7 is a voltage versus power relationship diagram of a microwave cooking device according to an embodiment of the present invention;

fig. 8 to 10 are block schematic views of a microwave cooking apparatus according to an embodiment of the present invention;

fig. 11 is a schematic circuit diagram of a filter of a microwave cooking apparatus according to an embodiment of the present invention;

fig. 12 is a graph of microwave frequency versus degree of suppression for a microwave cooking device in accordance with an embodiment of the present invention.

Description of the main element symbols: a microwave cooking apparatus 100;

microwave source 10, digital signal link unit 12, microwave signal generator 14, digital-to-analog converter 16, mixer 18, amplifier 20, cavity 30, antenna 40, processor 50, coupler 60, detector 70, filter 80.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the present description, "plurality" means two or more unless specifically defined otherwise.

In this specification, unless explicitly stated or limited otherwise, the first feature "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact with each other through another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

A control method of an embodiment of the present invention is applied to a microwave cooking apparatus 100. Referring to fig. 1, a microwave cooking apparatus 100 includes a microwave source 10, an amplifier 20, and an antenna 40. An amplifier 20 is connected to the microwave source 10 and the antenna 40, the microwave source 10 including a digital signal link unit 12. The control method comprises the following steps: the intermediate frequency signal generated by the digital signal link unit 12 is subjected to predistortion processing, so that the phase of the microwave signal input to the amplifier 20 is opposite to the phase of the microwave signal output by the amplifier 20 and the amplitude of the microwave signal is the same in the harmonic frequency band, and the higher harmonics generated by the amplifier 20 are cancelled.

Referring to fig. 1, a control method according to an embodiment of the present invention may be implemented by a microwave cooking apparatus 100 according to an embodiment of the present invention. Specifically, the microwave cooking apparatus 100 includes a microwave source 10, an amplifier 20, an antenna 40, and a processor 50. The processor 50 is connected to the microwave source 10, and the amplifier 20 is connected to the microwave source 10 and the antenna 40. The microwave source 10 includes a digital signal link unit 12. The processor 50 is configured to perform predistortion processing on the intermediate frequency signal generated by the digital signal link unit 12, so that the phase of the microwave signal input to the amplifier 20 is opposite to the phase of the microwave signal output from the amplifier 20 and the amplitude of the microwave signal is the same in the harmonic frequency band, thereby canceling out the higher harmonics generated by the amplifier 20.

In the control method and the microwave cooking device 100, the predistortion processing can be simulated in the design stage to guide the actual design, the suppression degree can be quantitatively designed, the predistortion processing algorithm does not need to increase the hardware cost, and the loss of the useful signal power is small.

Specifically, referring to fig. 1, the microwave cooking apparatus 100 may include a cavity 30, the cavity 30 may be used for containing food to be cooked, and an antenna 40 is installed in the cavity 30. The microwave source 10 may be a semiconductor microwave source 10, and the microwave source 10 may be used to generate microwave energy for heating food. The microwave source 10 includes a digital signal link unit 12, the digital signal link unit 12 may be a digital signal generator, the digital signal link unit 12 may implement signal output of any waveform, and the digital signal link unit 12 may output an intermediate frequency signal after predistortion processing, that is, output the intermediate frequency signal. The processor 50 is connected to the microwave source 10, and can perform predistortion processing on the intermediate frequency signal generated by the digital signal link unit 12, so that the phase of the microwave signal input to the amplifier 20 is opposite to the phase of the microwave signal output from the amplifier 20 and the amplitude of the microwave signal is the same in the harmonic frequency band, and the higher harmonics generated by the amplifier 20 are cancelled, so that the microwave signal amplified by the amplifier 20 is input to the antenna 40, and the antenna 40 radiates the microwave signal into the cavity 30 to cook food in the cavity 30. In the embodiment of the present invention, the amplifier 20 is a final amplifier 20. The amplitudes are the same, it being understood that the amplitudes are exactly the same or deviate within a desired range.

The predistortion treatment can be used for preprocessing a distorted signal generated when a microwave signal passes through the amplifier 20, after a small signal emitted by the microwave source 10 is amplified by the amplifier 20, because the nonlinear effect of the amplifier 20 can generate a plurality of distorted products such as spurs and higher harmonics, before the small signal enters the amplifier 20, the microwave signal is predistorted, a frequency component capable of canceling the distortion is added to the microwave signal, so that after the microwave small signal with additional frequency passes through the amplifier 20, the additional frequency component of the microwave signal is opposite in phase and the same in amplitude with the distorted product generated by the amplifier 20, namely, the amplitude of the superimposed additional frequency component and the distorted product is 0, and the superimposed additional frequency component and the distorted product are cancelled with each other, so that the distorted products such as the higher harmonics generated by the amplifier 20 are cancelled, and the microwave cooking device 100 can effectively suppress the higher harmonics without increasing any hardware cost, without loss of useful microwave signal power while ensuring the heating efficiency of the microwave source 10.

Referring to fig. 2 to 4, fig. 2 is a graph of an output spectrum of the microwave source 10 without pre-distortion, where an abscissa is a frequency of a microwave signal and an ordinate is an amplitude of the microwave signal, and as shown in fig. 2, in the case of no pre-distortion, a baseband intermediate frequency spectrum is consistent with an output spectrum of the microwave source 10, an absolute frequency of the baseband intermediate frequency spectrum is low, and an absolute frequency of the output spectrum of the microwave source 10 is high; fig. 3 is a diagram of a baseband intermediate frequency spectrum of a predistortion process, in which the abscissa represents the frequency of an intermediate frequency signal and the ordinate represents the amplitude of the intermediate frequency signal, fig. 4 is a diagram of an output spectrum of a microwave source 10 after the predistortion process, in which the abscissa represents the frequency of a microwave signal and the ordinate represents the amplitude of a microwave signal, and it can be seen from fig. 3 that, in the case of the predistortion process, the baseband intermediate frequency spectrum has more harmonic frequency components with opposite phases on both sides than the output frequency spectrum of the microwave source 10. In this way, in the process of amplifying the baseband intermediate frequency signal after the predistortion processing by the amplifier 20, the distortion products such as higher harmonics generated by the amplifier 20 can be cancelled, so that the microwave cooking apparatus 100 can effectively suppress the higher harmonics.

Referring to fig. 5, in some embodiments, the microwave source 10 includes a microwave signal generator 14, and the control method includes:

performing digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal;

mixes the analog intermediate frequency signal with the microwave signal generated by the microwave signal generator 14 and generates a microwave signal that is input to the amplifier 20. In this way, the digital signal after the predistortion processing is converted into an analog intermediate frequency signal by the digital-to-analog converter 16, so that the analog intermediate frequency signal can be mixed and adjusted with the microwave signal in the mixer 18, and the analog intermediate frequency signal is up-converted into a useful microwave signal (radio frequency signal).

The control method of the embodiment of the present invention may be implemented by the microwave cooking apparatus 100 of the embodiment of the present invention. In particular, the microwave source 10 includes a microwave signal generator 14, a digital-to-analog converter 16, and a mixer 18. The digital-to-analog converter 16 is connected to the digital signal link unit 12 and the mixer 18, the mixer 18 is connected to the microwave signal generator 14, and the digital-to-analog converter 16 is configured to perform digital-to-analog conversion on the intermediate frequency signal to obtain an analog intermediate frequency signal. The mixer 18 is used to mix the analog intermediate frequency signal with the microwave signal generated by the microwave signal generator 14 and generate a microwave signal that is input to the amplifier 20.

Referring to fig. 7, the output end of the digital signal link unit 12 is connected to the input end of the digital-to-analog converter 16, and the if signal output by the digital signal link unit 12 can be digital-to-analog converted in the digital-to-analog converter 16 and output through the output end of the digital-to-analog converter 16, so as to obtain an analog if signal. The mixer 18 has two input terminals connected to the digital-to-analog converter 16 and the microwave signal generator 14, respectively. The digital-to-analog converter 16 may generate an analog intermediate frequency signal, the microwave signal generator 14 may generate a microwave signal, and the analog intermediate frequency signal and the microwave signal may be modulated and mixed in the mixer 18 to obtain a radio frequency signal. The amplifier 20 may be connected to the mixer 18, and the rf signal output from the mixer 18 is input to the amplifier 20, and the amplifier 20 amplifies power, that is, in the embodiment of the present invention, the rf signal may be understood as a microwave signal input to the amplifier 20.

In some embodiments, referring to fig. 6, microwave cooking apparatus 100 includes coupler 60 and detector 70. Coupler 60 connects amplifier 20 to antenna 40, and detector 70 connects coupler 60. The control method comprises the following steps: the operation of the microwave source 10 is controlled in accordance with the electrical signal output by the detector 70. Thus, sampling by coupler 60 allows detector 70 to detect the electrical signal of the microwave signal, which in turn controls the operation of microwave source 10.

Referring to fig. 6, the control method according to the embodiment of the present invention can be implemented by the microwave cooking apparatus 100 according to the embodiment of the present invention. Specifically, the microwave cooking apparatus 100 includes a coupler 60 and a detector 70, the coupler 60 is connected to the amplifier 20 and the antenna 40, the detector 70 is connected to the coupler 60, and the processor 50 is configured to control the operation of the microwave source 10 according to an electrical signal output from the detector 70. Coupler 60, detector 70 and processor 50 have inputs and outputs. The coupler 60 is provided with two output terminals and one input terminal. Coupler 60 has an input connected to the output of amplifier 20, one output of coupler 60 connected to antenna 40 and the other output connected to the input of detector 70. The coupler 60 can output a portion of the rf signal incident on the cavity 30 and convert the rf signal into an electrical signal via the detector 70, so that the detector 70 can output the electrical signal to control the operation of the microwave source 10. Wherein the coupler 60 samples a portion of the rf signal and inputs the portion of the rf signal to the detector 70 for conversion. The electrical signal may be a voltage signal or a current signal.

In some embodiments, controlling the operation of the microwave source 10 based on the electrical signal output by the detector 70 includes: it is determined whether the amplitude of the signal output by the digital signal link unit 12 needs to be adjusted or whether the gain of the amplifier 20 needs to be adjusted or whether the amplitude of the signal output by the digital signal link unit 12 needs to be adjusted and the gain of the amplifier 20 needs to be adjusted based on the electrical signal output by the detector 70. In this manner, by adjusting the amplitude of the signal output by the digital signal link unit 12 and/or adjusting the gain of the amplifier 20, the higher harmonics output by the microwave source 10 of the microwave cooking apparatus 100 can be effectively suppressed.

The control method of the embodiment of the present invention may be implemented by the microwave cooking apparatus 100 of the embodiment of the present invention. Specifically, processor 50 is configured to determine whether an adjustment of the amplitude of the signal output by digital signal link element 12 is required, or whether an adjustment of the gain of amplifier 20 is required, or whether an adjustment of the amplitude of the signal output by digital signal link element 12 and an adjustment of the gain of amplifier 20 are required, based on the electrical signal output by detector 70.

The output terminal of the detector 70 is connected to the input terminal of the processor 50, so that the rf signal separated by the coupler 60 can enter the detector 70 and be converted into an electrical signal, the electrical signal output by the detector 70 can be transmitted to the processor 50, the processor 50 can determine the amplitude of the signal according to the magnitude (e.g., voltage magnitude) of the electrical signal, determine whether the amplitude of the signal output by the digital signal link unit 12 needs to be adjusted and/or adjust the gain of the amplifier 20, and further enable the processor 50 to perform predistortion processing on the if signal generated by the digital signal link unit 12, so that the phase of the microwave signal input to the amplifier 20 in the harmonic frequency band is opposite to the phase and the amplitude of the microwave signal output by the amplifier 20 is the same, and further, the higher harmonics generated by the amplifier 20 are cancelled.

Referring to fig. 7, different voltage levels correspond to different output power levels, and the output power of the microwave signal is the amplitude of the microwave signal. When the processor 50 can judge that the amplitude of the signal becomes larger according to the magnitude of the voltage, the amplitude of the signal output by the digital signal link unit 12 can be reduced, or the gain of the amplifier 20 can be reduced, or both the amplitude of the signal output by the digital signal link unit 12 and the gain of the amplifier 20 can be reduced. When the processor 50 can judge that the amplitude of the signal becomes smaller according to the magnitude of the voltage, the amplitude of the signal output by the digital signal link unit 12 can be increased, or the gain of the amplifier 20 can be increased, or both the amplitude of the signal output by the digital signal link unit 12 and the gain of the amplifier 20 can be increased. It should be noted that the data shown in fig. 7 is an example of the present embodiment, and should be understood as being for explaining the relationship between power and voltage, and not limiting the scope of the present invention.

Referring to fig. 8, in an embodiment, the microwave signal generator 14 of the microwave source 10 may emit a microwave signal, which is input to the amplifier 20 through the mixer 18 for small signal power amplification, and then is coupled to the detector 70 through the coupler 60 for conversion of the electrical signal, and the detector 70 may output an electrical signal to the processor 50 for pre-distortion processing of the microwave signal, so that the phase of the microwave signal input to the amplifier 20 is opposite to the phase of the microwave signal output from the amplifier 20 and the amplitude of the microwave signal is the same in the harmonic frequency band, thereby canceling the higher harmonics generated by the amplifier 20. Then, the digital signal link unit 12 can output a baseband digital signal (intermediate frequency signal), which can be converted into an analog intermediate frequency signal by the digital-to-analog converter 16, and then converted into a radio frequency signal by the mixer 18. Then, the amplitude of the radio frequency signal is amplified by the amplifier 20, a small part of radio frequency energy is separated again before the radio frequency signal with the amplified amplitude enters the antenna 40, and then the radio frequency energy is transmitted to the detector 70 for voltage signal conversion, and then the processor 50 controls the operation of the microwave source 10 according to the electric signal output by the detector 70, so that the microwave cooking device 100 can effectively suppress the harmonic amplitude of the port of the antenna 40.

Referring to fig. 9 and 10, in some embodiments, the microwave cooking apparatus 100 includes a filter 80, and the filter 80 is connected to the output of the amplifier 20 and the antenna 40. In this way, the harmonics output by the microwave source 10 can be further suppressed by the filtering of the filter 80.

In the embodiment of fig. 10, a filter 80 is connected between the amplifier 20 and the coupler 60. The filter 80 may be a passive LC filter, the filter 80 having an input and an output. An input terminal of the filter 80 may be connected to an output terminal of the final amplifier 20 of the microwave cooking apparatus 100, and an output terminal of the filter 80 may be connected to the antenna 40. The filter 80 may be constructed using a plurality of rf capacitors and inductors with high power capacity, and referring to fig. 11, in one example, the filter 80 may include three capacitors and two inductors, and the circuit diagram of the filter 80 may be constructed in simulation software. In the simulation process, simulation can be performed according to the established circuit diagram, and the filter 80 is used for filtering the microwave signals of different frequency bands, so that the suppression degree of the microwave signals of the harmonic frequency band can be known in advance, and a suppression degree curve diagram corresponding to multiple harmonic signals can be obtained. Referring to fig. 12, in the illustrated embodiment, the abscissa represents the frequency of the microwave signal, and the ordinate represents the degree of suppression of the filter 80 corresponding to different frequencies. In one example, the frequency of the microwave signal emitted from the microwave source 10 may be 2.5GHZ, the frequency corresponding to 3 th harmonic is 7.5GHZ, the frequency corresponding to 5 th harmonic is 12.5GHZ, and the frequency corresponding to 7 th harmonic is 17.5GHZ, and the suppression degree corresponding to 3 rd harmonic, 5 th harmonic, and 7 th harmonic can be known from fig. 12. When the fact that the harmonic exceeds the limit is known through actual measurement, namely, redundant harmonic leakage is known, the effect of effective suppression can be achieved by improving the suppression degree of the filter 80 at the corresponding frequency point. Thus, simulation can be performed in the design stage of the microwave cooking apparatus 100, and the actual design can be guided, so that the suppression degree can be quantitatively designed.

In the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "an illustrative embodiment", "an example", "a specific example", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.