Aerosol generation apparatus

Abstract

Disclosed in the present application is an aerosol generation apparatus. The aerosol generation apparatus comprises a microwave generation module and a microwave amplification module, wherein the microwave amplification module comprises a power amplifier used for performing power amplification on a microwave signal generated by the microwave generation module, and a filter connected to an output end of the power amplifier. The aerosol generation apparatus is characterized in that the filter comprises a plurality of filter units, which are respectively used for suppressing harmonic signals of different orders, wherein each filter unit comprises a filtering microstrip line and a filtering capacitor, the filtering microstrip lines in the filter units are sequentially connected end to end, so as to form an output-end microstrip line, and the filtering capacitor in each filter unit is connected between an output end of the filtering microstrip line and the ground.

Description

Aerosol forming apparatus Technical Field

[0001] This invention relates to the field of microwave heating, and more particularly to an aerosol forming apparatus. Background Technology

[0002] In microwave communication products, power amplifiers (PAs) are required to amplify microwave signals. To balance the linearity, distortion, and signal-to-noise ratio of microwave signals, the gain of power amplifiers is designed with a certain degree of backoff, resulting in a power amplifier efficiency (PAE) that is not at its maximum, typically only around 50%. However, in microwave heating products, the power amplifier, as a key component for energy conversion and output, needs to maximize its PAE, while other performance indicators are generally not a concern. Therefore, the design of power amplifiers in microwave heating products cannot directly use design examples from microwave communication products as a reference; the microstrip circuits matched to the input / output terminals of the power amplifier need to be redesigned.

[0003] In microwave heating products, suppressing out-of-band harmonics (HOBs) is a method to improve the added efficiency of power amplifiers. Currently, to suppress HOBs, microstrip circuit stubs, cavity filters, and other filtering devices are typically connected to the output of the power amplifier. However, connecting microstrip circuit stubs introduces additional insertion loss and increases the circuit area, which is detrimental to product miniaturization design; while cavity filters have lower insertion loss, they result in excessive size and high cost. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide an aerosol forming device that addresses the technical defects of existing technologies, such as low efficiency, large area, large volume, and high cost.

[0005] The technical solution adopted by this application to solve its technical problem is as follows: an aerosol forming device is constructed, including a microwave generating module and a microwave amplification module. The microwave amplification module includes a power amplifier for amplifying the power of the input microwave signal and a filter connected to the output terminal of the power amplifier. The filter includes multiple filter units for suppressing different harmonic signals. Each filter unit includes a filter microstrip line and a filter capacitor. The filter microstrip lines in each filter unit are connected end to end in sequence to form an output microstrip line. The filter capacitor in each filter unit is connected between the output terminal of the filter microstrip line and ground.

[0006] Optionally, the number of filtering units is three, four, or five.

[0007] Optionally, it also includes an input microstrip line connected to the input terminal of the power amplifier, wherein the width of the input microstrip line increases in a stepped manner and the width of the output microstrip line decreases in a stepped manner.

[0008] Optionally, the number of filtering units is four, and the width of the filtering microstrip line of the first two filtering units is 2-3 mm, and the width of the filtering microstrip line of the last two filtering units is 0.8-1.2 mm.

[0009] Optionally, the input microstrip line includes a first microstrip line and a second microstrip line connected together, wherein the width of the first microstrip line is 0.8-1.2 mm and the width of the second microstrip line is 1-2.5 mm.

[0010] Optionally, it also includes a power supply unit, which includes a power supply microstrip line and a decoupling capacitor. The first end of the power supply microstrip line is connected to the output terminal of the power amplifier, the second end of the power supply microstrip line is connected to a DC power supply, the first end of the decoupling capacitor is connected to the second end of the second microstrip line, the second end of the decoupling capacitor is grounded, and the length of the power supply microstrip line is related to 1 / 4 of the fundamental wavelength of the microwave signal.

[0011] Optionally, the power supply unit further includes a power microstrip line with an impedance of 50 ohms, and the power microstrip line is connected between the second end of the power supply microstrip line and the DC power supply.

[0012] Optionally, it also includes:

[0013] The output coupling capacitor connected to the microstrip line at the output terminal; and / or,

[0014] The input coupling capacitor is connected to the microstrip line at the input terminal.

[0015] Optionally, the output coupling capacitor is disposed at the rear section of the microstrip line at the output terminal; and / or,

[0016] The input coupling capacitor is located at the front end of the microstrip line at the input terminal.

[0017] Optionally, the microwave amplification module further includes a dielectric layer and a ground layer respectively disposed below the input microstrip line and the output microstrip line. Through the technical solution of this application, by combining capacitors of appropriate parameters at different length positions of the output microstrip line, an equivalent low-pass, low-impedance multi-order filter is formed at the output of the power amplifier, which can effectively suppress out-of-band harmonics, thereby improving the additional efficiency of the power amplifier. Furthermore, compared with existing microstrip circuit stubs, cavity filters, and other filter devices, it is not only smaller in size and volume, meeting the design trend of product miniaturization, but also has lower circuit costs. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0019] Figure 1 is a circuit diagram of the microwave amplification module of an aerosol forming apparatus in one embodiment of this application;

[0020] Figure 2 is a physical diagram of the microwave amplification module of the aerosol forming apparatus in one embodiment of this application;

[0021] Figure 3 is a schematic diagram of microstrip lines laid out on a PCB board in one embodiment of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The aerosol forming apparatus of this application includes a microwave generating module and a microwave amplification module. The microwave generating module generates a microwave signal, and the microwave amplification module amplifies the microwave signal generated by the microwave generating module. Referring to Figures 1 and 2, in one embodiment, the microwave amplification module includes a power amplifier 10 and a filter 20. The power amplifier 10 amplifies the power of the input microwave signal, and the frequency band of the input microwave signal (i.e., the operating signal of the power amplifier 10) is, for example, 2.4 GHz to 2.5 GHz. The filter 20 is connected to the output terminal of the power amplifier 10 and is used to suppress out-of-band harmonics.

[0024] The filter 20 includes four filter units, each used to suppress different harmonic signals. Each filter unit includes a filter microstrip line and a filter capacitor. The filter microstrip lines in each filter unit are connected end-to-end to form an output microstrip line. The filter capacitor in each filter unit is connected between the output terminal of the filter microstrip line and ground. Specifically, referring to Figures 1 and 2, the first filter unit includes a filter microstrip line MSL5 and a filter capacitor C2; the second filter unit includes a filter microstrip line MSL6 and a filter capacitor C3; the third filter unit includes a filter microstrip line MSL7 and a filter capacitor C4; and the fourth filter unit includes filter microstrip lines MSL8 and MSL9 (filter microstrip lines MSL8 and MSL9 can be equivalent to a single microstrip line segment) and a filter capacitor C6. Furthermore, the filter microstrip lines MSL5, MSL6, MSL7, MSL8, and MSL9 are connected end-to-end to form an output microstrip line. Filter capacitor C2 is connected between the output terminal of filter microstrip line MSL5 and ground; filter capacitor C3 is connected between the output terminal of filter microstrip line MSL6 and ground; filter capacitor C4 is connected between the output terminal of filter microstrip line MSL7 and ground; and filter capacitor C6 is connected between the output terminal of filter microstrip line MSL9 and ground.

[0025] In addition, in each filtering unit, the length of the filtering microstrip line and the capacitance value of the filtering capacitor are related to the frequency of the harmonic signal suppressed by the corresponding filtering unit. Specifically, the length of the filtering microstrip line MSL5 and the capacitance value of the filtering capacitor C2 are related to the frequency of the first harmonic signal of the operating signal (e.g., 4.8 GHz to 5 GHz). For example, the length of the filtering microstrip line MSL5 is 1.0-2.0 mm, and the filtering capacitor C2 is a high-Q capacitor with a capacitance value of 0.5-4.0 pF, and is connected between the output terminal of the filtering microstrip line MSL5 and ground, forming a first-order LC low-pass filter unit equivalent to the filtering microstrip line MSL5. The length of the filter microstrip line MSL6 and the capacitance value of the filter capacitor C3 are related to the frequency of the second harmonic signal of the operating signal. For example, the length of the filter microstrip line MSL6 is 4.0-6.0 mm, and the filter capacitor C3 is a high-Q capacitor with a capacitance value of 0.5-4.0 pF, connected between the output terminal of the filter microstrip line MSL6 and ground, effectively forming a second-order LC low-pass filter unit with the filter microstrip line MSL6. The length of the filter microstrip line MSL7 and the capacitance value of the filter capacitor C4 are related to the frequency of the third harmonic signal of the operating signal. For example, the length of the filter microstrip line MSL7 is 2.0-3.0 mm, and the filter capacitor C4 is a high-Q capacitor with a capacitance value of 0.5-4.0 pF, connected between the output terminal of the filter microstrip line MSL7 and ground, effectively forming a third-order LC low-pass filter unit with the filter microstrip line MSL7. The lengths of the filter microstrip lines MSL8 and MSL9, and the capacitance value of the filter capacitor C6, are related to the frequency of the fourth harmonic signal of the working signal. For example, the total length of the filter microstrip lines MSL8 and MSL9 is 4.0-6.0 mm, and the filter capacitor C6 is a capacitor with a capacitance value of 0.2-1.0 pF, which is connected between the output terminal of the filter microstrip line MSL9 and ground, and together with the filter microstrip lines MSL8 and MSL9, they form an equivalent fourth-order LC low-pass filter unit.

[0026] Regarding this embodiment, it should be noted that each filtering unit is an equivalent LC low-pass filter unit, and four filtering units constitute a fourth-order low-pass filter. It should be understood that although this embodiment shows a fourth-order filter, in other embodiments, the order of the filter can be other numbers, such as third-order, fifth-order, etc. Correspondingly, the number of filtering units can also be three, five, etc. It should also be noted that, theoretically, the higher the order of the filter, the higher the suppression of harmonic orders, and the higher the efficiency of the microwave amplification module. However, in practical applications, considering that harmonic energy is mainly concentrated in low-order harmonics, and the energy distribution of higher-order harmonics (e.g., above the 6th order) is relatively small, and that if the number of filtering units is too large, it will also increase the size and cost of the microwave amplification module, therefore, the number of filtering units can be three, four, or five, preferably four. Furthermore, since each filter unit has its own energy loss, when more filter units are set, the energy loss of the corresponding filter unit may exceed the energy of the higher harmonics when suppressing higher harmonics. Therefore, a larger number of filter units does not actually improve efficiency.

[0027] Furthermore, in this embodiment, the width of the output microstrip lines (e.g., MSL5, MSL6, MSL7, MSL8, and MSL9 connected end-to-end) decreases in a stepped manner. Additionally, the microwave amplification module in this embodiment also includes an input microstrip line connected to the input of the power amplifier 10, and the width of this input microstrip line increases in a stepped manner. Regarding this embodiment, it should first be noted that since the internal impedance of the power amplifier (e.g., 8.5 + j * 27.486 ohms) is smaller than the external line impedance (50 ohms), impedance matching is required at the input and output of the power amplifier when designing the microwave amplification module. Moreover, since the impedance of the microstrip line is mainly related to its width, and also to its thickness, the thickness of the line and the ground medium, and the dielectric constant of the dielectric, when the thickness of the microstrip line, the thickness of the line and the ground medium, and the dielectric constant of the dielectric are determined, the closer the microstrip line is to the power amplifier, the larger its width, and the closer its impedance is to the internal impedance of the power amplifier; the farther away from the power amplifier, the smaller the width of the microstrip line, and the closer its impedance is to the external line impedance. Therefore, this stepped input and output microstrip line can reduce the power loss of microwave signals, thereby improving the additional efficiency of the power amplifier.

[0028] It should also be noted that the impedances at the input and output terminals of the power amplifier are not exactly equal. The impedance at the input terminal is slightly greater than that at the output terminal. Therefore, when designing the input and output microstrip lines, as shown in Figure 2, the width of the end of the input microstrip line should be slightly smaller than the width of the beginning segment of the input microstrip line.

[0029] Furthermore, referring to Figures 1 and 2, when the number of filter units is four, the width of the filter microstrip lines (i.e., filter microstrip lines MSL5 and MSL6) in the first two filter units is 2-3 mm; the width of the filter microstrip lines (i.e., filter microstrip lines MSL7, MSL8, and MSL9) in the last two filter units is 0.8-1.2 mm. In this embodiment, the output microstrip line composed of filter microstrip lines MSL5, MSL6, MSL7, MSL8, and MSL9 can be equivalently represented as an inductor, forming an LC filter network with each filter capacitor, and can also be equivalently represented as an impedance, using impedance gradients to perform impedance matching for the power amplifier. In other words, while achieving out-of-band harmonic suppression, good impedance matching can also be achieved. Moreover, during impedance matching, filter microstrip line MSL5 serves as the impedance transformation line at the output of the power amplifier, enabling impedance matching with the output of the power amplifier. From the MSL6 to the MSL7 microstrip line, the linewidth decreases in a stepped manner, achieving a gradual change in impedance, which can be used for impedance matching with external lines.

[0030] Furthermore, referring to Figures 1 and 2, the input microstrip line includes a first microstrip line MSL1 and a second microstrip line MSL2 connected together. The width of the first microstrip line MSL1 is 0.8-1.2 mm, and the width of the second microstrip line MSL2 is 1-2.5 mm. In this embodiment, the first microstrip line MSL1 is a 50Ω impedance line, and its length is not required; the second microstrip line MSL2 is an input impedance transformation line, and its length can be 1.0-3.0 mm.

[0031] Furthermore, referring to Figures 1 and 2, the microwave amplification module of this embodiment also includes a feeding unit 30, which includes a feeding microstrip line MSL3 and a decoupling capacitor C1. The decoupling capacitor C1 can be, for example, a high-Q capacitor of 5.6pF to 15pF. The first end of the feeding microstrip line MSL3 is connected to the output terminal (drain) of the power amplifier 10, and the second end of the feeding microstrip line MSL3 is connected to the DC power supply Vd. The first end of the decoupling capacitor C1 is connected to the second end of the feeding microstrip line MSL3, and the second end of the decoupling capacitor C1 is grounded. The length of the feeding microstrip line MSL3 is related to 1 / 4 of the fundamental wavelength of the microwave signal, for example, 12.0-16.0 mm. Additionally, its width is 0.8-1.2 mm, and its resistance is 50 ohms.

[0032] In this embodiment, the feed microstrip line MSL3 serves as the feed line to the drain of the power amplifier. Its length is related to 1 / 4 of the fundamental wavelength (λ) of the microwave signal; that is, a λ / 4 microstrip line is used to feed the power amplifier. For the fundamental signal in the microwave signal, the feed unit appears as an open circuit when viewed from the drain of the power amplifier transistor, preventing it from conducting. Therefore, it prevents the fundamental signal from leaking to the DC power supply, thus reducing fundamental signal loss and preventing the DC power supply from being affected by the fundamental signal. Simultaneously, for the second harmonic signal in the microwave signal, the feed unit appears as a short circuit, preventing the second harmonic from flowing out through the DC path. In summary, the feed microstrip line MSL3 can transmit the DC voltage signal from the DC power supply to the drain of the power amplifier 10, but the microwave signal cannot flow out from the feed unit. This not only makes the DC power supply more stable, ensuring good performance of the power system, but also reduces microwave power loss and improves the additional efficiency of the power amplifier.

[0033] Furthermore, referring to Figures 1 and 2, the power supply unit 30 also includes a power microstrip line MSL4 with an impedance of 50 ohms, and the power microstrip line MSL4 is connected between the second end of the power supply microstrip line MSL3 and the DC power supply. This power microstrip line MSL4 is used for impedance matching with external lines, and its length is not required.

[0034] Furthermore, since the DC power signal output by the DC power supply can reach the output port (OUT) of the microwave amplification module and the input port (IN) of the microwave amplification module along the output microstrip line through the feed unit 30 and the power amplifier 10, in order to prevent the DC power signal from reaching the output port and the input port, referring to Figures 1 and 2, the microwave amplification module in this embodiment also includes an output coupling capacitor C5 and an input coupling capacitor C7 (not shown in Figure 1, refer to Figure 2), wherein the output coupling capacitor C5 is connected to the output microstrip line and the input coupling capacitor C7 is connected to the input microstrip line. In this embodiment, the output coupling capacitor C5 and the input coupling capacitor C7 can isolate the DC power signal respectively to prevent the DC power signal from reaching the output port and the input port of the microwave amplification module.

[0035] Furthermore, referring to Figures 1 and 2, the output coupling capacitor C5 is located at the rear section of the output microstrip line, and the input coupling capacitor C7 is located at the front section of the input microstrip line. In this embodiment, the closer the microstrip line is to the rear section of the output microstrip line, the closer its resistance is to 50 ohms, and the better it matches the impedance of the DC power supply. Similarly, the closer the microstrip line is to the front section of the input microstrip line, the closer its resistance is to 50 ohms, and the better it matches the impedance of the DC power supply. Therefore, by placing the output coupling capacitor C5 at the rear section of the output microstrip line and the input coupling capacitor C7 at the front section of the input microstrip line, the DC power supply signal can be more effectively prevented from reaching the output and input ports of the microwave amplifier module.

[0036] Finally, regarding the microstrip lines in this embodiment, such as MSL1, MSL2, MSL3, MSL4, MSL5, MSL6, MSL7, MSL8, and MSL9, it should be noted that, referring to Figure 3, when laying out the microstrip lines on the PCB board, three parts are arranged sequentially from top to bottom: microstrip line 1, dielectric layer 2, and copper foil layer (ground layer) 3. Furthermore, microstrip line 1 and the ground layer can, for example, use copper foil with a thickness of 0.035 mm, and the dielectric layer can be made of RO4350B circuit board material with a thickness of 0.508 mm. Additionally, the shapes of all microstrip lines (MSL1, MSL2, MSL3, MSL4, MSL5, MSL6, MSL7, MSL8, and MSL9) in this embodiment include, but are not limited to, straight lines, arcs, serpentine lines, and right-angle bends / cuts.

[0037] In summary, the technical solutions of the above embodiments improve the additional efficiency of the power amplifier through the following improvements:

[0038] 1. Harmonic suppression: By combining capacitors of appropriate parameters at different lengths of the microstrip line at the output end, an equivalent low-pass, low-impedance fourth-order LC filter is formed, which can effectively suppress out-of-band harmonics, thereby improving the additional efficiency of the power amplifier.

[0039] 2. Impedance matching: A stepped microstrip line is used to achieve impedance gradation, thereby matching the input / output terminals of the power amplifier and improving the additional efficiency of the power amplifier.

[0040] 3. Using λ / 4 microstrip lines for power feeding: This prevents the fundamental frequency signal of the microwave signal from leaking to the DC power supply, reduces the loss of the fundamental frequency signal, and thus improves the additional efficiency of the power amplifier.

[0041] Test results show that by implementing the technical solution of the above embodiments, the additional efficiency of the power amplifier can be increased to 78%~80%, which is much greater than 50%.

[0042] In addition, the technical solution of this embodiment, besides improving the additional efficiency of the power amplifier, also has the following beneficial effects:

[0043] 1. The length of the microstrip line in both the horizontal and vertical directions does not exceed λ / 2. Compared with existing microstrip circuit stubs, cavity filters and other filter devices, the size and volume are smaller, which meets the design trend of product miniaturization.

[0044] 2. The microwave power amplifier module can be directly designed onto the PCB board. Compared with existing cavity filters and other filter devices, it does not require special substrates such as silicon, sapphire or diamond, resulting in lower circuit costs.

[0045] 3. It can prevent microwave signals from leaking to the DC power supply, thus ensuring the good performance of the power supply system.

[0046] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An aerosol forming apparatus, comprising a microwave generating module and a microwave amplification module, wherein the microwave amplification module includes a power amplifier for amplifying the microwave signal generated by the microwave generating module and a filter connected to the output terminal of the power amplifier, characterized in that, The filter includes multiple filter units for suppressing different harmonic signals. Each filter unit includes a filter microstrip line and a filter capacitor. The filter microstrip lines in each filter unit are connected end to end to form an output microstrip line. The filter capacitor in each filter unit is connected between the output end of the filter microstrip line and ground.

2. The aerosol forming apparatus according to claim 1, characterized in that, The number of filtering units is three, four, or five.

3. The aerosol forming apparatus according to claim 1 or 2, characterized in that, The microwave amplification module also includes an input microstrip line connected to the input terminal of the power amplifier, wherein the width of the input microstrip line increases in a stepped manner, and the width of the output microstrip line decreases in a stepped manner.

4. The aerosol forming apparatus according to claim 3, characterized in that, The number of filter units is four, and the width of the filter microstrip line of the first two filter units is 2-3mm, while the width of the filter microstrip line of the last two filter units is 0.8-1.2mm.

5. The aerosol forming apparatus according to claim 3, characterized in that, The input microstrip line includes a first microstrip line and a second microstrip line connected together. The width of the first microstrip line is 0.8-1.2 mm, and the width of the second microstrip line is 1-2.5 mm.

6. The aerosol forming apparatus according to claim 3, characterized in that, The microwave amplification module further includes a power feeding unit, which includes a power feeding microstrip line and a decoupling capacitor. The first end of the power feeding microstrip line is connected to the output terminal of the power amplifier, and the second end of the power feeding microstrip line is connected to a DC power supply. The first end of the decoupling capacitor is connected to the second end of the second microstrip line, and the second end of the decoupling capacitor is grounded. The length of the power feeding microstrip line is related to 1 / 4 of the fundamental wavelength of the microwave signal.

7. The aerosol forming apparatus according to claim 6, characterized in that, The power supply unit also includes a power microstrip line with an impedance of 50 ohms, and the power microstrip line is connected between the second end of the power supply microstrip line and the DC power supply.

8. The aerosol forming apparatus according to claim 6, characterized in that, The microwave amplification module also includes: The output coupling capacitor (C5) is connected to the microstrip line at the output terminal; and / or, The input coupling capacitor (C7) is connected to the microstrip line at the input terminal.

9. The aerosol forming apparatus according to claim 8, characterized in that, The output coupling capacitor (C5) is located at the rear section of the microstrip line at the output terminal; and / or, The input coupling capacitor (C7) is located at the front end of the microstrip line at the input terminal.

10. The aerosol forming apparatus according to claim 3, characterized in that, The microwave amplification module also includes a dielectric layer and a ground layer respectively disposed below the input microstrip line and the output microstrip line.

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