Microwave cooking equipment

Abstract

The invention discloses microwave cooking equipment. The microwave cooking equipment comprises a cavity; a first microwave source; the first patch antenna is installed in the cavity and electrically connected with the first microwave source, and the first patch antenna comprises a rectangular first radiation element; the second patch antenna is installed in the cavity and electrically connected with the first microwave source, and the second patch antenna comprises a rectangular second radiation element; the long side of the first radiation element and the long side of the second radiation element are parallel to the first direction; on the same side, the wide edge of the first radiation element and the wide edge of the second radiation element deviate by a first distance in the first direction, and the first distance is odd times of one fourth of the working wavelength of the first microwave source. According to the microwave cooking equipment, current coupling between the two patch antennas can be reduced, and damage to the first microwave source is avoided to a certain extent.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a microwave cooking device. Background Art

[0002] Current microwave cooking devices primarily utilize a solid-state source to emit microwaves, which are then fed into a cavity via an antenna to heat the food. To improve heating uniformity, microwave cooking devices often include two antennas. However, when these two antennas feed microwaves into the cavity, co-frequency coupling can occur, causing radiated energy from one antenna to transfer to the other. If the radiated energy is excessive, antenna coupling can damage the solid-state source. Summary of the Invention

[0003] The embodiments of the present invention provide a microwave cooking device to solve at least one of the above-mentioned technical problems.

[0004] A microwave cooking device according to an embodiment of the present invention includes:

[0005] cavity;

[0006] First microwave source;

[0007] a first patch antenna, mounted in the cavity and electrically connected to the first microwave source, the first patch antenna comprising a rectangular first radiating element;

[0008] a second patch antenna, the second patch antenna being mounted in the cavity and electrically connected to the first microwave source, the second patch antenna comprising a rectangular second radiating element;

[0009] The long side of the first radiation element and the long side of the second radiation element are parallel to the first direction;

[0010] On the same side, the broadside of the first radiation element and the broadside of the second radiation element are offset by a first distance along the first direction, and the first distance is an odd multiple of one quarter of the operating wavelength of the first microwave source.

[0011] In the above-mentioned microwave cooking device, the wide sides of the radiating elements of the two patch antennas are offset by an odd multiple of one-quarter of the working wavelength to meet the quarter-wavelength converter principle, thereby converting the coupling between the two patch antennas into an open circuit process, thereby reducing the current coupling between the two patch antennas and avoiding damage to the first microwave source to a certain extent.

[0012] In some embodiments, the first distance is one quarter of an operating wavelength of the first microwave source.

[0013] In some embodiments, the first patch antenna and the second patch antenna are disposed on the top of the cavity, the cavity is provided with a chamber, and the first radiating element and the second radiating element are located in the chamber.

[0014] In some embodiments, the first patch antenna includes a first coaxial line connecting the first radiating element and the first microwave source, and the second patch antenna includes a second coaxial line connecting the second radiating element and the first microwave source.

[0015] In some embodiments, the width of the first radiation element is one-half or an even multiple of one-half of the operating wavelength of the first microwave source;

[0016] The width of the second radiation element is half of the working wavelength of the first microwave source or an even multiple of half.

[0017] In some embodiments, the microwave cooking device includes a second microwave source, the operating wavelength of the first microwave source is a first wavelength, the operating wavelength of the second microwave source is a second wavelength, and the relationship between the first wavelength and the second wavelength is not half, or an even multiple of not half.

[0018] In some embodiments, the frequency range corresponding to the second wavelength is [2400 MHz, 2500 MHz], and the frequency range corresponding to the first wavelength is [900 MHz, 930 MHz].

[0019] In some embodiments, the microwave cooking device includes a third antenna connected to the second microwave source, the third antenna is located at the bottom of the cavity, and the first patch antenna and the second patch antenna are located at the top of the cavity.

[0020] In some embodiments, the microwave cooking device includes a waveguide connecting the second microwave source and the third antenna, the waveguide being a bandpass filter that allows microwaves having the second wavelength to pass therethrough but does not allow microwaves having the first wavelength to pass therethrough.

[0021] In certain embodiments, the third antenna comprises a stirring antenna.

[0022] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 is a perspective view of a microwave cooking device according to an embodiment of the present invention;

[0025] Figure 2 A schematic structural diagram of a first patch antenna and a second patch antenna according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the offset between the first patch antenna and the second patch antenna according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the structure of a first patch antenna according to an embodiment of the present invention;

[0028] Figure 5 This is a diagram showing the decoupling results of two patch antennas according to an embodiment of the present invention;

[0029] Figure 6 Graphs showing S11 and S21 results of the patch antenna according to an embodiment of the present invention in the 2450 MHz frequency band;

[0030] Figure 7 This is a measured S11 diagram of the third antenna in the 915 MHz frequency band according to an embodiment of the present invention.

[0031] Description of main component reference numerals:

[0032] Microwave cooking device 100 , cavity 12 , first patch antenna 14 , second patch antenna 16 , first radiating element 18 , second radiating element 20 , cavity 21 , first metal ground plate 22 , first dielectric layer 24 , first coaxial line 26 , second coaxial line 28 , third antenna 30 , waveguide 32 . DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, removable connections, or integral connections. They may refer to mechanical connections or electrical connections. They may refer to direct connections or indirect connections through an intermediary, and they may refer to internal communication between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0037] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0038] Please refer to Figures 1 to 3 A microwave cooking device 100 provided in an embodiment of the present invention includes a cavity 12, a first microwave source (not shown), a first patch antenna 14, and a second patch antenna 16. The first patch antenna 14 is mounted in the cavity 12 and electrically connected to the first microwave source. The first patch antenna 14 includes a rectangular first radiating element 18. The second patch antenna 16 is mounted in the cavity 12 and electrically connected to the first microwave source. The second patch antenna 16 includes a rectangular second radiating element 20. The long side of the first radiating element 18 and the long side of the second radiating element 20 are parallel to a first direction. On the same side, the wide side of the first radiating element 18 and the wide side of the second radiating element 20 are offset along the first direction by a first distance D, where the first distance D is an odd integer multiple of one-quarter of the operating wavelength of the first microwave source.

[0039] In the above-mentioned microwave cooking device 100, the wide sides of the radiating elements of the two patch antennas are offset by an odd multiple of one-quarter of the working wavelength to meet the quarter-wavelength converter principle, and the coupling between the two patch antennas is converted into an open circuit process, thereby reducing the current coupling between the two patch antennas and avoiding damage to the first microwave source to a certain extent.

[0040] Specifically, the microwave cooking device 100 includes but is not limited to a microwave oven, a microwave steamer, a microwave oven, a microwave oven, etc. The microwave cooking device 100 can be an embedded microwave cooking device or a desktop microwave cooking device.

[0041] The cavity 12 is provided with a chamber 21 in which food can be placed for heating. When the first microwave source is in operation, microwaves are generated, which are fed into the chamber 21 via the first patch antenna 14 and the second patch antenna 16 to heat the food in the chamber 21.

[0042] The present invention does not specifically limit the shape and material of the cavity 12. Optionally, the shape of the cavity 12 can be substantially rectangular, and the material of the cavity 12 can be stainless steel. Optionally, the first microwave source can be installed on the top of the cavity 12.

[0043] Optionally, combine Figure 4 The first patch antenna 14 may include a first metal ground plane 22 and a first dielectric layer 24, wherein the first radiating element 18 and the first metal ground plane 22 are respectively provided on two opposite surfaces of the first dielectric layer 24 along the thickness direction of the first patch antenna 14. The second patch antenna 16 may include a second metal ground plane and a second dielectric layer, wherein the second radiating element 20 and the second metal ground plane are respectively provided on two opposite surfaces of the second dielectric layer along the thickness direction of the second patch antenna 16. The thickness direction may refer to Figure 4 The up and down directions in .

[0044] Optionally, the first patch antenna 14 and the second patch antenna 16 may share a dielectric layer and a metal ground plane. The first radiating element 18 and the second radiating element 20 are disposed on the same surface of the dielectric layer along the thickness direction of the patch antenna, and the metal ground plane is disposed on the other surface of the dielectric layer along the thickness direction of the patch antenna.

[0045] The first radiating element 18 and the second radiating element 20 can be positioned toward the interior of the chamber 21 to radiate microwaves into the chamber 21. When using patch antennas to feed microwave energy, current coupling is easily generated between the two same-frequency antennas, causing the radiated energy to be transferred from the first patch antenna 14 to the second patch antenna 16, and vice versa. When the radiated energy is too high, antenna coupling can damage the first microwave source (e.g., a solid-state source). Therefore, the issue of same-frequency decoupling needs to be considered during the design process.

[0046] Theoretically, the long side of the patch antenna does not radiate, but a corresponding current is generated at the wide side, which is radiated through current coupling. During the design process, due to the high reflections within the sealed cavity 12, in order to ensure the same-frequency decoupling effect, since the long side does not radiate, the wide side of the first radiating element 18 and the wide side of the second radiating element 20 are offset along the first direction by a first distance D on the same side. The first distance D is an odd multiple of one-quarter of the operating wavelength of the first microwave source, thereby satisfying the quarter-wavelength converter principle and converting the coupling between the two patch antennas into an open-circuit process, thereby reducing the current coupling between the two patch antennas, avoiding damage to the first microwave source to a certain extent, and at the same time, improving the radiation efficiency of the antenna.

[0047] exist Figure 3 In the embodiment shown, the first direction is the front-to-back direction. It is understood that in other embodiments, the first direction may also be other directions. On the same side, the wide side of the first radiating element 18 and the wide side of the second radiating element 20 are offset along the first direction by a first distance D, that is, the wide sides of the two radiating elements are staggered along the first direction by the first distance D. Figure 3On the rear side, the offset distance between the broadside of the first radiating element 18 and the broadside of the second radiating element 20 is equal to the offset distance between the broadside of the first radiating element 18 and the broadside of the second radiating element 20 on the front side, which is a first distance D. The offset refers to the offset that occurs when the broadside of the first radiating element 18 and the broadside of the second radiating element 18 are not aligned in the first direction when the broadside of the second radiating element 20 and the broadside of the first radiating element 18 are aligned in the first direction on the same side.

[0048] The operating frequency of the first microwave source is f1, and the operating wavelength of the first microwave source is a first wavelength λ1. λ1 = c / f1, where c is the speed of light. The first distance D is an odd integer multiple of one-quarter of the operating wavelength of the first microwave source, such as one-quarter (1 times), three-quarters (3 times), five-quarters (5 times), etc. In one example, the first microwave source is a solid-state source, the operating frequency f1 of the first microwave source is 915 MHz, and the first wavelength λ1 is approximately 32.79 centimeters (cm). In other words, the first distance D can be 32.79×1 / 4 cm, 32.79×3 / 4 cm, 32.79×5 / 4 cm, 32.79×7 / 4 cm, or other odd integer multiples of one-quarter of the first wavelength. It should be understood that the present invention does not specifically limit the operating frequency of the first microwave source.

[0049] In some embodiments, the first distance D is one quarter of the operating wavelength of the first microwave source.

[0050] Therefore, the space occupied by the patch antenna can be reduced while meeting the requirements of co-frequency decoupling.

[0051] Specifically, the first distance D is one quarter of the operating wavelength of the first microwave source, that is, the first distance D is 1 times one quarter of the operating wavelength of the first microwave source. In this way, while meeting the requirement of co-frequency decoupling, the offset of the first radiating element 18 and the second radiating element 20 along the first direction can be reduced, thereby reducing the space occupied by the patch antenna and making the microwave cooking device 100 more compact.

[0052] Please combine Figure 5 In one embodiment, the frequency range corresponding to the first wavelength is [900MHz, 930MHz], and three frequencies M1 = 902MHz, M2 = 915MHz, and M3 = 928MHz are selected respectively. From the S21 curve in the figure, it can be seen that S21 is below -10dB, indicating that 90% of the microwave energy is not coupled. Figures 5 to 7 In the figure, the horizontal axis represents frequency and the vertical axis represents energy.

[0053] In some embodiments, the first patch antenna 14 and the second patch antenna 16 are disposed on the top of the cavity 12 . The cavity 12 has a chamber 21 . The first radiating element 18 and the second radiating element 20 are located in the chamber 21 .

[0054] In this way, the food can be heated conveniently by microwave.

[0055] Specifically, the first patch antenna 14 and the second patch antenna 16 are disposed at the top of the cavity 12, and the food is placed on the bottom plate of the cavity 12. Microwaves heat the food from top to bottom, resulting in a wide heating range and good heating effect. Furthermore, the upward surface of the food is generally larger, allowing more microwaves to directly radiate to the surface of the food, thereby facilitating microwave heating of the food.

[0056] Please combine Figures 1 to 3 The first patch antenna 14 is offset backward by a first distance D compared to the second patch antenna 16 , or the second patch antenna 16 is offset forward by the first distance D compared to the first patch antenna 14 .

[0057] In some embodiments, first patch antenna 14 includes a first coaxial line 26 connecting first radiating element 18 and the first microwave source, and second patch antenna 16 includes a second coaxial line 28 connecting second radiating element 20 and the first microwave source.

[0058] Therefore, the radiating element can be fed by means of a coaxial line.

[0059] Specifically, after the first microwave source generates microwaves, the microwaves can be transmitted to the first radiation element 18 via the first coaxial line 26. The first radiation element 18 radiates the microwaves into the chamber 21. The microwaves are transmitted to the second radiation element 20 via the second coaxial line 28. The second radiation element 20 radiates the microwaves into the chamber 21.

[0060] In some embodiments, the size of the broadside of the first radiation element 18 is one-half or an even multiple of one-half of the operating wavelength of the first microwave source;

[0061] The width of the second radiation element 20 is half of the working wavelength of the first microwave source or an even multiple of half.

[0062] Thus, the first radiation element 18 and the second radiation element 20 can efficiently radiate the microwaves emitted by the first microwave source.

[0063] Specifically, according to the design principles of patch antennas, the width of the radiating element (radiating edge) is related to half the operating wavelength or an even multiple of half. Patch antennas are more efficient when the width of the radiating element is half the operating wavelength or an even multiple of half. Antenna efficiency measures its ability to convert input power into radiated power. Antenna efficiency is defined as the ratio of the antenna's radiated power to its input power, reflecting how effectively the antenna converts electromagnetic wave energy.

[0064] The width of the first radiation element 18 is W1. In some examples, W1 = 1 / 2×λ1, 2 / 2×λ1, 4 / 2×λ1, 6 / 2×λ1, 8 / 2×λ1 or other even multiples of half of λ1, where λ1 is the operating wavelength of the first microwave source.

[0065] The width of the second radiating element 20 is W2. In some examples, W2=1 / 2×λ1, 2 / 2×λ1, 4 / 2×λ1, 6 / 2×λ1, 8 / 2×λ1 or other even multiples of half of λ1.

[0066] Optionally, the width of the first radiating element 18 is equal to the width of the second radiating element 20. Optionally, the width of the first radiating element 18 is unequal to the width of the second radiating element 20.

[0067] In some embodiments, the microwave cooking device 100 includes a second microwave source, the operating wavelength of the first microwave source is a first wavelength, the operating wavelength of the second microwave source is a second wavelength, and the relationship between the first wavelength and the second wavelength is not half, or an even multiple of half.

[0068] In this way, inter-frequency decoupling can be achieved.

[0069] Specifically, in the related art, microwave cooking equipment is generally a microwave oven based on a single microwave source (such as a 2.45 GHz magnetron), and a low-frequency microwave cooking equipment based on a solid-state microwave source. There is no multi-band microwave cooking equipment, so the existing low-frequency microwave cooking equipment does not need to consider the coupling problem between the 2.45 GHz antenna and the low-frequency antenna.

[0070] In this embodiment, the microwave cooking device 100 is based on an ISM (Industrial Scientific Medical) multi-band microwave cooking system. Optionally, a first microwave source (such as a solid-state source) is used to emit energy at a low frequency and radiate it through a patch antenna, and a second microwave source (such as a magnetron) is used to emit energy at a high frequency and radiate it through a third antenna 30.

[0071] The multi-band microwave cooking device 100 can better combine the advantages of large wavelength in the low frequency band and small wavelength in the high frequency band, so that the electromagnetic field distribution in the closed cavity 12 is more uniform, achieving uniform thawing and heating of food, and consistent temperature inside and outside.

[0072] In the microwave cooking device 100, electromagnetic field energy is fed into the cavity 12 through an antenna or waveguide 32. Since it contains microwave sources of multiple frequency bands, an antenna is required to efficiently feed the electromagnetic field energy of one frequency band into the cavity 12 while suppressing the electromagnetic field energy of another frequency band to avoid interfering with or damaging the operation of the microwave source.

[0073] In this embodiment, the frequency corresponding to the first wavelength is the first frequency, and the frequency corresponding to the second wavelength is the second frequency. Because the relationship between the first wavelength and the second wavelength is not half, or an even multiple of half, the patch antenna corresponding to the first frequency does not meet the radiation range of the second frequency when designed. Therefore, the first patch antenna 14 and the second patch antenna 16 corresponding to the first frequency have poor radiation effects at the second frequency, indicating that the patch antenna receives less microwave energy generated by the second microwave source when operating, and has little or no impact on the normal operation of the first microwave source.

[0074] Optionally, the first frequency is less than the second frequency. Optionally, the microwave energy generated by the second microwave source is radiated through the stirring antenna. Similarly, the stirring antenna receives less microwave energy generated by the first microwave source when it is in operation, which has little impact on the normal operation of the second microwave source or is insufficient to affect the normal operation of the second microwave source.

[0075] In some embodiments, the second wavelength corresponds to a frequency range of [2400 MHz, 2500 MHz], and the first wavelength corresponds to a frequency range of [900 MHz, 930 MHz].

[0076] From this, the specific frequency range can be determined.

[0077] Specifically, the first frequency range is [900MHz, 930MHz], and the second frequency range is [2400MHz, 2500MHz]. According to the design principles of patch antennas, the length of the radiating edge (wide side) of the radiating element is related to half of the operating wavelength and its even multiples. When the first frequency is 915MHz and the second frequency is 2450MHz, the first wavelength is approximately 32.79cm and the second wavelength is approximately 12.24cm. The wavelength lengths corresponding to 915MHz and 2450MHz are approximately 2.7 times. Therefore, the 915MHz patch antenna design does not meet the 2450MHz radiation range, and the 915MHz patch antenna has poor radiation performance at 2450MHz. A similar understanding applies to other frequencies in the first frequency range and other frequencies in the second frequency range.

[0078] When the high-frequency antenna (corresponding to the second microwave source) is turned on, if the low-frequency antenna resonates at the high frequency, it is easy to receive energy from the high frequency band. Excessive energy will also cause damage to the first microwave source. Since the patch antenna corresponding to the first frequency (such as 915MHz) adopts a different frequency decoupling design, the resonance of the patch antenna at the second frequency (such as 2450MHz) is suppressed. Figure 6The S11 results in the figure show that the patch antenna resonates well at 915 MHz, with S11 < -10 dB. This indicates that the patch antenna resonates well at 915 MHz. At 2450 MHz, S11 is -1 dB, indicating that the patch antenna receives or radiates less energy at this frequency, insufficient to affect the first microwave source. The 2450 MHz frequency band can be referred to as [2400 MHz, 2500 MHz].

[0079] Optionally, the second frequency range is [2440 MHz, 2460 MHz].

[0080] In some examples, the first frequency is f1, where f1=900 MHz, 902 MHz, 910 MHz, 915 MHz, 920 MHz, 928 MHz, 930 MHz, or another frequency of [900 MHz, 930 MHz].

[0081] In some examples, the second frequency is f2, where f2=2400 MHz, 2420 MHz, 2440 MHz, 2450 MHz, 2460 MHz, 2480 MHz, 2500 MHz, or another frequency in the range of [2400 MHz, 2500 MHz].

[0082] In some embodiments, the microwave cooking device 100 includes a third antenna 30 connected to the second microwave source. The third antenna 30 is disposed at the bottom of the cavity 12 , and the first patch antenna 14 and the second patch antenna 16 are disposed at the top of the cavity 12 .

[0083] This allows the food to be heated more evenly.

[0084] Specifically, when the first microwave source is operating, part of the microwave energy generated can be radiated directly from the top of the cavity 12 to the top of the food, while another part can be radiated to the inner wall of the cavity 21 and reflected to the food. When the second microwave source is operating, part of the microwave energy generated can be radiated directly from the bottom of the cavity 12 to the bottom of the food, while another part can be radiated to the inner wall of the cavity 21 and reflected to the food. This allows both the top and bottom of the food to be directly heated by the microwave energy, thereby heating the food more evenly.

[0085] Furthermore, in an embodiment of the present invention, the microwave cooking device 100 adopts a design of synchronous decoupling and heterogeneous frequency decoupling, so that most of the microwave energy radiated by the first microwave source and the microwave energy radiated by the second microwave source can be absorbed by food. At the same time, damage to the first microwave source and the second microwave source can be avoided to a certain extent.

[0086] The present invention does not specifically limit the structure of the third antenna 30. Optionally, the third antenna 30 includes a stirring antenna. This can increase the radiation range of the microwave energy generated by the second microwave source, and heat the food more evenly.

[0087] Specifically, the stirring antenna may include a motor and an antenna, and the antenna is connected to the output shaft of the motor. When the second microwave source is working, the motor can be started to drive the antenna to rotate, thereby causing the microwave energy generated by the second microwave source to radiate into the cavity 12 from different directions, thereby increasing the radiation range of the microwave energy and making the heating effect on the food more uniform.

[0088] In some embodiments, the microwave cooking apparatus 100 includes a waveguide 32 connecting the second microwave source and the third antenna 30 , the waveguide 32 being a bandpass filter that allows microwaves having the second wavelength to pass therethrough but does not allow microwaves having the first wavelength to pass therethrough.

[0089] In this way, the third antenna 30 can be decoupled at different frequencies, thereby further reducing the microwave energy loss in the cavity 12 and avoiding damage to the second microwave source.

[0090] Specifically, the waveguide 32 connects the second microwave source and the third antenna 30. The microwave energy generated by the second microwave source when in operation is transmitted to the third antenna 30 via the waveguide 32 and radiated into the cavity 21. The microwave energy generated by the first microwave source when in operation is radiated into the cavity 21 via the first patch antenna 14 and the second patch antenna 16.

[0091] Since the waveguide 32 is a bandpass filter that allows microwaves with the second wavelength to pass through but does not allow microwaves with the first wavelength to pass through, the third antenna 30 cannot radiate microwave energy at the first wavelength, thereby reducing the loss of microwave energy in the cavity 12 caused by the microwave energy of the first wavelength being received by the third antenna 30, and also preventing the microwave energy of the first wavelength from damaging the second microwave source. Figure 7 The second wavelength corresponds to a frequency of 2450 MHz, the first wavelength corresponds to a frequency of 915 MHz, and the third antenna 30 cannot radiate at 915 MHz. The 915 MHz frequency band may refer to [900 MHz, 930 MHz].

[0092] Optionally, the second microwave source comprises a magnetron.

[0093] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative descriptions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0094] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A microwave cooking device, characterized in that: include: cavity; First microwave source; a first patch antenna, mounted in the cavity and electrically connected to the first microwave source, the first patch antenna comprising a rectangular first radiating element; a second patch antenna, the second patch antenna being mounted in the cavity and electrically connected to the first microwave source, the second patch antenna comprising a rectangular second radiating element; The long side of the first radiation element and the long side of the second radiation element are parallel to the first direction; On the same side, the broadside of the first radiation element and the broadside of the second radiation element are offset by a first distance along the first direction, and the first distance is an odd multiple of one quarter of the operating wavelength of the first microwave source.

2. The microwave cooking device according to claim 1, characterized in that The first distance is one quarter of the operating wavelength of the first microwave source.

3. The microwave cooking device according to claim 1, characterized in that: The first patch antenna and the second patch antenna are arranged on the top of the cavity, the cavity is provided with a cavity, and the first radiation element and the second radiation element are located in the cavity.

4. The microwave cooking device according to claim 1, wherein: The first patch antenna includes a first coaxial line connecting the first radiating element and the first microwave source, and the second patch antenna includes a second coaxial line connecting the second radiating element and the first microwave source.

5. The microwave cooking device according to claim 1, characterized in that: The width of the first radiation element is one-half of the operating wavelength of the first microwave source or an even multiple of one-half; The width of the second radiation element is half of the working wavelength of the first microwave source or an even multiple of half.

6. The microwave cooking device according to claim 1, characterized in that The microwave cooking device includes a second microwave source, the operating wavelength of the first microwave source is a first wavelength, the operating wavelength of the second microwave source is a second wavelength, and the relationship between the first wavelength and the second wavelength is not half, or an even multiple of not half.

7. The microwave cooking device according to claim 6, characterized in that The frequency range corresponding to the second wavelength is [2400 MHz, 2500 MHz], and the frequency range corresponding to the first wavelength is [900 MHz, 930 MHz].

8. The microwave cooking device according to claim 6, characterized in that The microwave cooking device includes a third antenna connected to the second microwave source. The third antenna is arranged at the bottom of the cavity, and the first patch antenna and the second patch antenna are arranged at the top of the cavity.

9. The microwave cooking device according to claim 8, characterized in that: The microwave cooking device includes a waveguide connecting the second microwave source and the third antenna, the waveguide being a bandpass filter that allows microwaves having the second wavelength to pass therethrough but does not allow microwaves having the first wavelength to pass therethrough.

10. The microwave cooking device according to claim 8, characterized in that The third antenna includes a stirring antenna.

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