LDO (Low Dropout Regulator)-based temperature control resonant cavity high frequency sweep circuit design and

Abstract

The invention discloses a high sweep frequency circuit design and PCB layout method based on an LDO temperature control resonant cavity, and the method comprises the steps: 1, carrying out the layout design of a PCB structure, sequentially arranging a radio frequency module, a main control module and a data collection module in parallel at the lower part of a PCB, and arranging an LDO template at the upper part of the PCB; 2, arranging a radio frequency chip close to a terminal interface of the radio frequency chip, and arranging a data acquisition chip including a detection chip and an analog-to-digital conversion chip close to the terminal interface of the radio frequency chip; 3, arranging a main control chip included in the main control module between the radio frequency chip and the data acquisition chip, and controlling normal power supply of the radio frequency chip and the data acquisition chip; fourthly, the LDO chip is arranged above the PCB and used for supplying power to the whole system, the LDO template reserves a space above the PCB to serve as a heat dissipation area, and temperature control of the LDO is facilitated. The technical problems that high frequency sweep in a closed space is prone to environmental temperature change, impedance matching is carried out on different loads, and the PCB layout wiring length, the electromagnetic interference, the signal quality and the like are solved.

Description

Technical Field

[0001] The present invention relates to the field of electronic communication technology. More specifically, the present invention relates to a high-frequency sweep circuit design and PCB layout method based on an LDO temperature-controlled resonant cavity. Background Art

[0002] A frequency sweep circuit changes the output frequency within a predetermined frequency range and obtains the frequency response of a device at different frequencies. High-frequency frequency sweep circuits are primarily used in microwave bands and high-frequency electronic devices, such as testing the resonance point of a microwave resonant cavity.

[0003] Traditional high-frequency sweep circuits typically consist of multiple modules. First, a frequency synthesizer or direct digital synthesizer (DDS) with good phase noise and frequency stability is typically used as the signal source. Second, an amplifier module, typically an RF amplifier, is used to boost signal strength. Then, an appropriate detector (such as a power meter or spectrum analyzer) is selected to monitor the resonant cavity's response to the swept signal. Finally, a data acquisition system (such as an ADC interface) is used to record and analyze the resonant cavity's response data.

[0004] There are some defects in traditional high-frequency circuit design: (1) Traditional frequency sweep circuits often require multiple discrete components, resulting in a larger system size and higher power consumption.

[0005] (2) The performance of traditional frequency sweep circuits is often affected by temperature changes.

[0006] (3) Due to impedance matching problems in traditional high-frequency sweep designs, such as signal reflection, the quality of the RF signal is reduced.

[0007] To address these issues, researchers have proposed various solutions, such as replacing DDS and RF amplifier modules with RF modules to reduce the number of discrete components, optimizing PCB heat dissipation to control temperature, and selecting low-power devices. Impedance mismatches can be addressed by adding impedance-matching resistors between the source and load. While these solutions can alleviate the aforementioned issues to a certain extent, prolonged high-frequency sweeps in a confined space increase the temperature over time, and this temperature instability can severely impact the sweep results. Furthermore, when the load changes, the previously matched impedance becomes mismatched, degrading signal quality.

[0008] In the design of high-frequency sweep circuits, PCB (printed circuit board) layout and routing are crucial, directly impacting circuit performance, signal quality, and interference immunity. High-frequency signal PCB layout design prioritizes signal integrity, especially for high-frequency signals, ensuring impedance matching between the source and load. Secondly, minimize high-frequency signal trace lengths. Finally, utilize grounding to reduce electromagnetic interference. Finally, ensure optimal heat dissipation.

[0009] However, there are some difficulties in high-frequency signal layout and routing: (1) Component layout is difficult. To minimize signal trace length, components need to be placed densely. However, to reduce electromagnetic interference, the wiring spacing should not be too small, which makes component layout difficult.

[0010] (2) Component routing is difficult. Routing requires consideration of specific impedance matching and precise control of signal line width and structure, which makes routing difficult. In addition, differential routing is generally used to improve signal anti-interference performance, which also increases routing difficulties. Summary of the Invention

[0011] One purpose of the present invention is to provide a high-frequency sweep circuit design and PCB layout method based on an LDO temperature-controlled resonant cavity, which solves technical problems such as the susceptibility of high-frequency sweeping in a confined space to ambient temperature changes, impedance matching of different loads, PCB layout and wiring length, electromagnetic interference, and signal quality.

[0012] In order to solve the above technical problems, the present invention provides a high-frequency sweep circuit design and PCB layout method based on an LDO temperature-controlled resonant cavity, comprising the following steps: Step 1: PCB structure layout design: The RF module, main control module, and data acquisition module are arranged in parallel on the lower part of the PCB board. The LDO template is set on the upper part of the PCB board. The data acquisition module includes a detection module and an analog-to-digital conversion module arranged in sequence; Step 2: Place the RF chip included in the RF module close to its terminal interface, and the data acquisition chip corresponding to the data acquisition module, including the detection chip and the analog-to-digital conversion chip, also close to its terminal interface; Step 3: The main control chip included in the main control module is set between the radio frequency chip and the data acquisition chip to control the normal power supply of the radio frequency chip and the data acquisition chip; Step 4: The LDO chip corresponding to the LDO template is set above the PCB board to power the entire system. The LDO template reserves space above the PCB board as a heat dissipation area to facilitate temperature control of the LDO.

[0013] Preferably, the main control chip, radio frequency chip and data acquisition chip, and the filter decoupling capacitors corresponding to each chip are all set close to the corresponding chip power supply pins, and the remaining peripheral components of each chip are evenly distributed on the periphery of the corresponding chip and wiring positions and heat dissipation areas are reserved.

[0014] Preferably, the PCB wiring method is specifically as follows: First, high-frequency signal lines are routed using a parallel routing strategy. Each chip and the corresponding output terminal interface are placed close together for the shortest routing possible. High-frequency signal lines are shielded using copper wrapping. Secondly, the clock signal of the main control chip is routed first, followed by the data line. In addition, the power line, i.e. the LDO line, is routed with a thicker line than the higher-frequency signal line. Finally, the low-frequency signal lines are routed according to the set line spacing, and the low-frequency signal lines do not cross with the power lines and high-frequency signal lines.

[0015] Preferably, for the processing of ground lines, first, the digital ground and the analog ground are separated to prevent the noise of digital signals from interfering with the analog signals; second, the analog ground and the digital ground are connected at a single grounding point to reduce the noise conduction caused by the ground loop; finally, a ground plane is used in the high-frequency loop to reduce electromagnetic interference.

[0016] Preferably, the heat dissipation area is made of high thermal conductivity material, and the top and bottom layers of the double-layer PCB are paved with high thermal conductivity material to cover the entire PCB area; thermal holes or heat dissipation channels are added on the ground plane close to the LDO module.

[0017] Preferably, a programmable adjustable resistor is connected in parallel in the output circuit of the LDO temperature control circuit, which is used to adjust the load current and control temperature changes; the LDO module is also provided with a temperature monitoring chip, which is arranged next to the LDO chip. The temperature monitoring chip is used to monitor temperature changes and transmit them to the main control chip. The resistance of the programmable adjustable resistor is controlled by programming through the main control chip.

[0018] Preferably, the LDO temperature control process is as follows: S01: Initialize the temperature monitoring chip device and programmable load resistor; S02: Obtain the ambient temperature value through the temperature monitoring chip; S03: Determine whether the ambient temperature value is the same as the preset temperature value. If they are the same, jump to S07; otherwise, jump to S04; S04: Determine whether the ambient temperature is lower than the preset temperature. If the ambient temperature is lower than the preset temperature, the process jumps to S05; otherwise, the process jumps to S06. S05: Use the main control chip to control and reduce the adjustable load resistance value; S06: Use the main control chip to control and increase the adjustable load resistance value; S07: When the ambient temperature value is equal to the preset temperature value, the temperature control is ended.

[0019] Preferably, the RF module adopts single-ended output, an unknown load is connected between the RF chip and the detection chip, and a programmable adjustable matching resistor is connected in parallel between the RF chip output and the unknown load to realize dynamic adaptive matching resistance.

[0020] Preferably, the dynamic adaptive matching resistor implementation process is as follows: S01: Initialize the RF chip, detection chip, and analog-to-digital conversion chip, configure their registers, make the RF chip enter the frequency sweep mode, and initialize the value of the programmable adjustable matching resistor to its minimum value; S02: Send a start command via the serial port to start the dynamic adaptive impedance matching operation; S03: Increase the programmable matching resistance value in the smallest step through the main control chip; S04: Under the current matching resistance value, the RF chip is used to perform a frequency sweep within a given frequency range, and then the voltage value after detection is obtained by the analog-to-digital conversion module, and the return loss of the signal is obtained by conversion; S05: Determine whether the programmable resistor reaches the end of adjustment, that is, whether the resistance value of the programmable resistor reaches the maximum value of the preset structure. If not, jump to S03, otherwise jump to S06; S06: Optimize and find the resistance value with the smallest echo coefficient, and use it as the matching impedance value of the current load, and adjust the programmable resistor to this value; S07: End.

[0021] The present invention has at least the following beneficial effects: 1. The present invention connects a programmable adjustable resistor in parallel to the LDO output to adjust the load current and control temperature changes. At the same time, in addition to adding the programmable resistor, the complexity of other circuits is not increased, and the technical problem that high frequency sweeping in a confined space is easily affected by ambient temperature changes is solved.

[0022] 2. The present invention proposes dynamic adaptive impedance matching. By replacing traditional impedance matching resistors with programmable adjustable resistors, there is no need to strictly consider the impedance matching problem during layout and routing. When the load changes, dynamic adaptive impedance matching is performed first. At the same time, this method greatly simplifies the trouble of impedance matching in layout and routing and the impedance matching problem when facing unknown loads, solving the technical difficulty of impedance matching for different loads.

[0023] 3. The present invention proposes a set of general wiring principles to reduce the length of high-frequency signal traces, reduce electromagnetic interference, and perform heat dissipation design, thereby improving the heat dissipation of LDO and the quality of high-frequency signals.

[0024] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the design diagram of the LDO temperature control circuit of the present invention; Figure 2This is a temperature monitoring circuit diagram of the present invention; Figure 3 This is the LDO temperature control flow chart of the present invention; Figure 4 This is a schematic diagram of the dynamic adaptive matching impedance adjustment principle of the present invention; Figure 5 This is a flow chart of the dynamic adaptive matching impedance adjustment of the present invention; Figure 6 This is the PCB layout and wiring process of the present invention; Figure 7 This is a schematic diagram of the PCB layout and wiring of the present invention. DETAILED DESCRIPTION

[0026] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below with reference to the accompanying drawings so that those skilled in the art can implement it according to the description.

[0027] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "horizontal", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 a limitation to the present invention.

[0028] The present invention proposes a high-frequency sweep circuit design and PCB layout method based on an LDO-based temperature-controlled resonant cavity.

[0029] First, in order to solve the technical problem that high frequency sweep in a confined space is easily affected by ambient temperature changes, a low-voltage linear regulator is proposed for temperature compensation and a feedback mechanism is introduced. LDO uses voltage difference to generate heat. The power calculation formula is: P=UI As we can see, changing the LDO's voltage drop or load current can alter its power, effectively controlling its heat generation. Therefore, changing the load current is used to control heat generation. The load current of the operating circuit is fixed, so a programmable resistor is connected in parallel with the LDO output to adjust the load current and control temperature fluctuations. Another purpose of the LDO is to power other chips, so, aside from adding a programmable resistor, it does not increase the complexity of other circuits.

[0030] Secondly, to address the technical difficulty of impedance matching for different loads, dynamic adaptive impedance matching was proposed. By replacing traditional impedance matching resistors with programmable adjustable matching resistors, there is no need to strictly consider impedance matching during layout and routing. When the load changes, dynamic adaptive impedance matching is first performed, that is, the resistance value of the matching impedance is continuously changed to obtain its return loss, that is, the intensity difference of the high-frequency signal from the source to the target and back again is measured. The greater the return loss, the stronger the reflected signal. The resistance value at the minimum return loss is used as the current matching impedance. This method greatly simplifies the trouble of impedance matching in layout and routing and the impedance matching problem when facing unknown loads.

[0031] Finally, to improve LDO heat dissipation and high-frequency signal quality, a set of general wiring guidelines are proposed. It's important to note that since impedance matching is optimized within the circuit, it's not necessary to consider it during layout and routing. The PCB layout includes the following structure, along with the corresponding routing settings.

[0032] RF chip. First, place the output end of the RF chip as close as possible to the output RF terminal, and the programmable adjustable matching resistor as close as possible to the other terminal. Second, the decoupling capacitor needs to be as close as possible to the power supply end of the RF chip to ensure the power supply quality of the chip. Then, other peripheral components of the RF chip should be evenly distributed around the RF chip, making sure to leave space for wiring and heat dissipation, about 0.5cm is sufficient.

[0033] Data acquisition chip. Place the data acquisition chip parallel to the RF chip and as close to the receiving terminal as possible (the received signal is also a high-frequency signal). Similarly, place the decoupling capacitor close to the power supply pin, and place the remaining peripheral components evenly around the chip.

[0034] Main control chip. The main control chip is mainly used to control the normal operation of the entire system. The main control chip is placed between the RF chip and the data acquisition chip to control the normal power supply of the RF chip and the data acquisition chip. The decoupling capacitor is close to the power supply pin of the main control chip, and the components are evenly placed around the chip.

[0035] For the LDO, choose a chip with a wide operating range. Place the LDO chip above the PCB, leaving a large enough heat dissipation area for the LDO to control its temperature. Similarly, place the temperature monitoring chip next to the LDO.

[0036] Wiring. First, high-frequency signals should be routed as short as possible. Since the layout is as close to the output terminals as possible, this ensures that the high-frequency signal traces are sufficiently short and uses a parallel routing strategy. Secondly, the clock signal of the main control chip should be routed first, followed by the data line. Furthermore, the power line, i.e., the LDO trace, should be as thick as possible to reduce voltage loss along the wire.

[0037] Ground processing. First, separate the digital ground from the analog ground to prevent digital noise from interfering with the analog signal. Second, connect the analog and digital grounds at a single ground point to reduce noise conduction caused by ground loops. Use ground planes in high-frequency loops to reduce electromagnetic interference. Specific embodiments

[0038] In this embodiment, the RF chip used is the ADF4351. The data acquisition chip used is composed of the AD8362 for detection and the ADS1116 for analog-to-digital conversion. The temperature monitoring chip used is the DS18B20, and the LDO chip is the AS1117. The programmable resistor is the AD5220. All of the aforementioned chips can be replaced with chips of equal or superior performance.

[0039] The design of LDO temperature control compensation circuit is shown in the attached Figure 1 As shown. The LDO temperature control circuit mainly consists of the AMS1117 step-down chip, the programmable adjustable resistor AD5220 and the filter capacitor. The main control can program the AD5220 through the IIC interface to control its resistance value, thereby changing the load current and controlling the heating power. Figure 2 This is the temperature monitoring circuit design diagram, which is composed of DS18B20. The LDO temperature control flow chart is as shown in the attached figure. Figure 3 shown.

[0040] S01: Initialize DS18B120 device, programmable load resistor.

[0041] S02: Obtain the ambient temperature value through the temperature monitoring chip.

[0042] S03: Determine whether the ambient temperature value is the same as the preset temperature value. If they are the same, jump to S07; otherwise, jump to S04.

[0043] S04: Determine whether the ambient temperature is lower than a preset temperature. If the ambient temperature is lower than the preset temperature, the process jumps to S05; otherwise, the process jumps to S06.

[0044] S05: Use the IIC interface to control and reduce the adjustable load resistance value.

[0045] S06: Use the IIC interface to control and increase the adjustable load resistance value.

[0046] S07: When the ambient temperature value is equal to the preset temperature value, the temperature control is ended.

[0047] The dynamic adaptive impedance matching principle of RF chip is shown in the attached Figure 4 As shown in the figure, it is completed by the RF module and the data acquisition module (detection module and analog-to-digital conversion module). The RF module uses a single-ended output and adds an adjustable resistor for dynamic impedance matching at the output. The dynamic adaptive matching resistor implementation process is shown in the attached figure. Figure 5 The process is as follows: S01: Initialize the ADF4351 RF chip, the AD8362 detector, and the ADS1116 analog-to-digital converter, configuring their registers to put the ADF4351 into sweep mode. Initialize the programmable resistor to its minimum value.

[0048] S02: Send a start command via the serial port to start the dynamic adaptive impedance matching operation.

[0049] S03: Use the IIC interface to increase the programmable adjustable resistance value in the smallest step.

[0050] S04: Under the current matching resistance value, the RF chip is used to perform frequency sweeping within a given frequency range, and then the voltage value after detection is obtained by the analog-to-digital conversion module, and the return loss of the signal is obtained by conversion.

[0051] S05: Determine whether the programmable resistor has reached the end of adjustment, that is, whether the resistance of the programmable resistor is the maximum value of the preset structure. If not, jump to S03, otherwise jump to S06.

[0052] S06: Optimize and find the resistance value with the smallest echo coefficient, use it as the matching impedance value of the current load, and adjust the programmable resistor to this value.

[0053] S07: End.

[0054] In order to ensure signal quality and heat dissipation effect, the proposed layout strategy process is as shown in the attached Figure 6 shown.

[0055] S01: Start PCB design and complete the update from schematic to PCB.

[0056] S02: For the high-frequency modules, namely the RF module, the detection module, and the analog-to-digital conversion module, place the high-frequency chips corresponding to the RF module, the detection module, and the analog-to-digital conversion module close to their respective terminal interfaces. The filter decoupling capacitors are placed close to the chip power pins. In addition, other peripheral components are evenly distributed about 0.5 cm around the chip. Layout reference attachment Figure 7 .

[0057] S03: Other modules, including the main control module and LDO module, control the normal operation of the system and are placed between the RF module and the detection module. Peripheral components are evenly distributed around the main control box. The filter decoupling capacitors need to be close to the power supply pins of the main control. The LDO is placed above the high-frequency module to power the entire system. At the same time, most of the space above is reserved as the heat dissipation area of ​​the PCB board, and high thermal conductivity materials such as copper are selected to increase heat dissipation. Layout reference Figure 7 .

[0058] S04: Route high-frequency signal lines first, keeping them as short as possible and ensuring they are as parallel as possible to reduce electromagnetic interference. Shield high-frequency signal lines with copper to prevent crosstalk. Next, route the power lines. Power lines should be as wide as possible to reduce voltage differences across the wires and maximize heat dissipation. Finally, route the low-frequency signal lines. Keep them as close together as possible to avoid crossing with power lines and high-frequency signal lines.

[0059] S05: First, to maximize heat dissipation, create a large copper ground plane on both the top and bottom layers of a double-layer PCB, ensuring that the entire PCB surface is covered as much as possible. This ensures that the signal line's return path can effectively extend along the ground plane. Additionally, thermal vias or heat dissipation channels should be added to the ground plane, particularly near the LDO, to enhance heat conduction and dissipation.

[0060] S06: PCB layout and routing completed.

[0061] It will be understood that the present invention is described by way of some embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and embodiments. They can be fully applied to various fields suitable for the present invention, and further modifications can be easily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. Based on the LDO temperature-controlled resonant cavity high-sweep frequency circuit design and PCB layout method, it is characterized by: The steps include: Step 1: PCB structure layout design: The RF module, main control module, and data acquisition module are arranged in parallel on the lower part of the PCB board. The LDO template is set on the upper part of the PCB board. The data acquisition module includes a detection module and an analog-to-digital conversion module arranged in sequence; Step 2: Place the RF chip included in the RF module close to its terminal interface, and the data acquisition chip corresponding to the data acquisition module, including the detection chip and the analog-to-digital conversion chip, also close to its terminal interface; Step 3: The main control chip included in the main control module is set between the radio frequency chip and the data acquisition chip to control the normal power supply of the radio frequency chip and the data acquisition chip; Step 4: The LDO chip corresponding to the LDO template is set above the PCB board to power the entire system. The LDO template reserves space above the PCB board as a heat dissipation area to facilitate temperature control of the LDO.

2. The LDO temperature-controlled resonant cavity high-sweep frequency circuit design and PCB layout method according to claim 1, wherein: The main control chip, RF chip and data acquisition chip, and the filter decoupling capacitors corresponding to each chip are all set close to the corresponding chip power supply pins. The remaining peripheral components of each chip are evenly distributed on the periphery of the corresponding chip and wiring positions and heat dissipation areas are reserved.

3. The LDO temperature-controlled resonant cavity high-sweep frequency circuit design and PCB layout method according to claim 1, wherein: The specific PCB wiring method is: First, high-frequency signal lines are routed using a parallel routing strategy. Each chip and the corresponding output terminal interface are placed close together for the shortest routing possible. High-frequency signal lines are shielded using copper wrapping. Secondly, the clock signal of the main control chip is routed first, followed by the data line. In addition, the power line, i.e. the LDO line, is routed with a thicker line than the higher-frequency signal line. Finally, the low-frequency signal lines are routed according to the set line spacing, and the low-frequency signal lines do not cross with the power lines and high-frequency signal lines.

4. The method for designing a high-frequency sweep circuit based on an LDO temperature-controlled resonant cavity and a PCB layout as claimed in claim 3, wherein: Regarding ground processing, first, the digital ground is separated from the analog ground to prevent the noise of the digital signal from interfering with the analog signal; second, the analog ground and the digital ground are connected at a single grounding point to reduce the noise conduction caused by the ground loop; finally, a ground plane is used in the high-frequency loop to reduce electromagnetic interference.

5. The LDO temperature-controlled resonant cavity high-sweep frequency circuit design and PCB layout method according to claim 1, wherein: The heat dissipation area uses high thermal conductivity materials. The top and bottom layers of the double-layer PCB are paved with high thermal conductivity materials to cover the entire PCB area. Thermal holes or heat dissipation channels are added on the ground plane near the LDO module.

6. The method for designing a high-frequency sweep circuit based on an LDO temperature-controlled resonant cavity and a PCB layout as claimed in claim 1, wherein: A programmable adjustable resistor is connected in parallel to the output circuit of the LDO temperature control circuit, which is used to adjust the load current and control temperature changes. The LDO module is also provided with a temperature monitoring chip, which is arranged next to the LDO chip. The temperature monitoring chip is used to monitor temperature changes and transmit them to the main control chip. The programmable adjustable resistor is programmed by the main control chip to control its resistance.

7. The method for designing a high-frequency sweep circuit based on an LDO temperature-controlled resonant cavity and a PCB layout as claimed in claim 6, wherein: The LDO temperature control process is as follows: S01: Initialize the temperature monitoring chip device and programmable load resistor; S02: Obtain the ambient temperature value through the temperature monitoring chip; S03: Determine whether the ambient temperature value is the same as the preset temperature value. If they are the same, jump to S07; otherwise, jump to S04; S04: Determine whether the ambient temperature is lower than the preset temperature. If the ambient temperature is lower than the preset temperature, the process jumps to S05; otherwise, the process jumps to S06. S05: Use the main control chip to control and reduce the adjustable load resistance value; S06: Use the main control chip to control and increase the adjustable load resistance value; S07: When the ambient temperature value is equal to the preset temperature value, the temperature control is ended.

8. The LDO temperature-controlled resonant cavity high-sweep frequency circuit design and PCB layout method according to claim 2, wherein: The RF module uses single-ended output. An unknown load is connected between the RF chip and the detection chip. A programmable adjustable matching resistor is connected in parallel between the RF chip output and the unknown load to achieve dynamic adaptive matching resistance.

9. The method for designing a high-frequency sweep circuit based on an LDO temperature-controlled resonant cavity and a PCB layout as claimed in claim 8, wherein: The implementation process of dynamic adaptive matching resistor is as follows: S01: Initialize the RF chip, detection chip, and analog-to-digital conversion chip, configure their registers, make the RF chip enter the frequency sweep mode, and initialize the value of the programmable adjustable matching resistor to its minimum value; S02: Send a start command via the serial port to start the dynamic adaptive impedance matching operation; S03: Increase the programmable matching resistance value in the smallest step through the main control chip; S04: Under the current matching resistance value, the RF chip is used to perform a frequency sweep within a given frequency range, and then the voltage value after detection is obtained by the analog-to-digital conversion module, and the return loss of the signal is obtained by conversion; S05: Determine whether the programmable resistor reaches the end of adjustment, that is, whether the resistance value of the programmable resistor reaches the maximum value of the preset structure. If not, jump to S03, otherwise jump to S06; S06: Optimize and find the resistance value with the smallest echo coefficient, and use it as the matching impedance value of the current load, and adjust the programmable resistor to this value; S07: End.

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