An automatic matching design method for RF circuits based on optimization algorithm

Abstract

The present invention discloses an automatic matching design method for radio frequency circuits based on an optimization algorithm. Aiming at microwave systems used in the field of wireless transceivers, this method can easily solve the design problems of multi-band radio frequency circuits, antennas, etc. By designing and optimizing the matching circuit of the optimized radio frequency system and adopting the optimization of the analog search algorithm, the radio frequency circuit matching is automatically optimized, and the operating frequency band of the system or antenna is tuned. This design method overcomes the time-consuming and labor-intensive problem of manual tuning in circuit optimization. To implement the radio frequency system design, it is only necessary to design the corresponding one-stage or multi-stage matching circuit model, and set the numerical range of components such as capacitors, inductors, and resistors, and the required circuit value can be obtained through automatic optimization.

Description

Technical Field

[0001] The present invention relates to the field of Internet of Things, and more specifically, to an automatic matching design method for radio frequency circuits based on an optimization algorithm. Background Art

[0002] At present, the structure of mobile phones, tablets and other IoT (Internet of Things) terminals is becoming more and more complex and compact. The space for antenna design to achieve specific radiation performance has also become smaller, and the antenna design and RF circuit matching design are extremely difficult. Therefore, in a specific wireless transceiver terminal system, it is very meaningful to design a miniaturized antenna that uses smaller discrete components in the matching circuit to tune the antenna operating frequency to achieve specific antenna radiation performance. This design method can realize the movement of the antenna operating frequency in a limited space, thereby greatly reducing the dependence of the antenna design on the space size.

[0003] However, the current method of using multiple discrete components involves multiple types of components in the optimization process, and the range of value variation of discrete capacitors, inductors and resistors is very large, which makes manual adjustment difficult; and the method of using analytical methods to solve circuit matching, the theoretical values ​​obtained can only be used as a reference in practical applications, and when multiple frequency bands are involved, the solution process is very complicated.

[0004] Therefore, the use of automatic tuning of antenna operating frequency can greatly save debugging and testing time. Especially for dual-frequency and multi-frequency antenna designs, the use of automatic circuit matching tuning can greatly improve the tuning efficiency of the RF circuit system. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an automatic matching design method for radio frequency circuits based on an optimization algorithm. The method achieves precise movement of the antenna operating frequency point and optimized design of the matching circuit through efficient algorithm processing.

[0006] The method of the present invention obtains the electromagnetic scattering parameter results of the antenna or radio frequency circuit. This step is usually completed through electromagnetic simulation software or actual measurement, and an initial matching circuit design is established based on this.

[0007] Furthermore, the method of the present invention will load radio frequency components to perform standard matching circuit design. These components include resistors, capacitors, inductors, etc., and their types and values ​​will be preliminarily determined through the standard matching circuit design process.

[0008] Furthermore, the method of the present invention utilizes discrete components to tune the radio frequency circuit. During the tuning process, the parameters of these components, such as capacitance and inductance, are changed to observe changes in circuit performance.

[0009] Furthermore, the method of the present invention can optimize the parameters of components through a pattern search algorithm. The pattern search algorithm is an iterative algorithm for finding the minimum value of a function, which can automatically search and find the combination of component parameters that optimizes the matching performance of the radio frequency circuit.

[0010] Through the above steps, the method of the present invention can optimize the matching performance of the radio frequency circuit, thereby greatly reducing the dependence of the antenna design on the space size and improving the tuning efficiency of the radio frequency circuit system.

[0011] The method of the present invention exhibits significant beneficial effects in many aspects:

[0012] 1. The matching circuit is optimized and designed in an automated way, which greatly improves the design efficiency. Traditional RF circuit design often requires manual adjustment of component parameters, which is a cumbersome and error-prone process. The present invention uses a pattern search algorithm to automatically optimize parameters, which greatly reduces the designer's workload and improves the accuracy and efficiency of the design.

[0013] 2. The method of the present invention broadens the scope of application. Due to the use of an automated design method, the method is not only applicable to antenna design, but can also be applied to the automated matching of all radio frequency circuits. Whether it is wireless communication equipment, radar systems or other radio frequency applications, the method of the present invention can be used to optimize the design of matching circuits.

[0014] 3. By optimizing the matching circuit, the method of the present invention can achieve resonance of the wireless transceiver system within a specific frequency band, thereby improving the performance of the system. The optimized design of the matching circuit can reduce energy loss, improve signal transmission efficiency and quality, and thus improve the performance of the entire wireless transceiver system.

[0015] In summary, the present invention provides a radio frequency circuit matching design method based on a pattern search algorithm, which provides important practical value for the design of wireless transceiver terminal systems in the field of the Internet of Things through automated design methods, a wide range of applications, and excellent performance optimization effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of the overall design of the present invention;

[0017] Figure 2 This is the overall structure diagram of the dual-frequency antenna;

[0018] Figure 3 Load the antenna intrinsics before matching the circuit ;

[0019] Figure 4 is the radiation pattern of the antenna at 433MHz;

[0020] Figure 5 is the radiation pattern of the antenna at 868MHz;

[0021] Figure 6 It is a schematic diagram of dual-frequency radio frequency link matching;

[0022] Figure 7 After loading the matching circuit, the optimized ;

[0023] Figure 8 This is the curve of system working efficiency changing with frequency after loading the matching link;

[0024] Fig. 9 It is a 868MHz single-band antenna;

[0025] Fig.10 is the antenna's intrinsic resonant frequency, corresponding to ;

[0026] Fig.11 To load the matching circuit, the wireless transceiver link operating frequency band . DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the 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 a limitation on the present invention.

[0029] The embodiment of the present invention uses the pattern search method as an example to perform automatic circuit matching design, but the specific content of the invention is not limited to the pattern search method.

[0030] Example 1: Dual-band UHF antenna impedance matching design

[0031] For wireless radio frequency communication bands below 1 GHz (Sub-1 GHz), antenna design is very challenging. In wireless communication terminal systems used for short-range transmission and reception, the ISM band (Industrial Scientific Medical Band) allocated by the International Telecommunication Union (ITU) is often used, including radio communication bands such as 315 MHz, 433 MHz, 868 MHz and 915 MHz. In addition, one or more working frequency bands are often required in wireless systems. Since electromagnetic waves have strong interference in low-frequency bands and are prone to electromagnetic diffraction and electromagnetic interference, it is usually necessary to introduce an RF matching circuit to tune the intrinsic resonant frequency of the antenna, thereby changing the overall resonant frequency band of the wireless transceiver system.

[0032] This embodiment describes an intelligent RF circuit network matching method based on a pattern search method, and the optimization algorithm for this application type is not limited to the pattern search method. The pattern search method in this embodiment only provides a feasible method. The optimization algorithm can be a conjugate gradient method, Newton's method, square method, genetic algorithm, ant colony algorithm, particle swarm algorithm, simulated annealing algorithm and neural network algorithm.

[0033] In the embodiment, the antenna is used as an example, and the pattern search method is used to match and tune the system circuit. In the specific implementation process, this method is not limited to solving the matching problem of the antenna by intelligently loading the matching circuit, but can also be used for the automatic matching of all RF circuits to achieve the tuning of the corresponding working frequency bands such as antennas and RF circuits. Thereby, the impedance matching of the RF circuit network is achieved, and the purpose of the RF circuit network resonating in the corresponding frequency band is achieved. This kind of automatic matching method is used to accelerate the design process of the wireless transceiver link and ensure that the wireless transceiver system signal is more effectively transmitted in the circuit channel.

[0034] In this method, first, based on the antenna simulation model, RF circuit simulation model or electromagnetic scattering parameter results obtained by testing with instruments such as network analyzers, RF components are loaded for standard matching circuit design, and RF circuit tuning is performed using discrete components. Component parameters are optimized based on the pattern search algorithm to automatically achieve the optimal RF circuit matching performance, thereby avoiding the problem of difficulty in debugging and achieving performance targets caused by manual tuning or experimental testing methods.

[0035] In this embodiment, a dual-band UHF antenna is designed, which supports both 433MHz (corresponding to a frequency range of 433.05MHz~434.7HMz) and 868MHz (corresponding to a frequency range of 863MHz~870HMz) operating frequency bands. The design indicators meet the requirements of antenna size, material, radiation performance, etc. This design method can greatly save the design cost of the link transceiver circuit from the antenna front end to the module receiving end.

[0036] For this design method, a dual-band antenna is used. Figure 6 The matching circuit 1 in the circuit achieves dual-frequency circuit performance matching in the 433MHz and 868MHz frequency bands, and realizes the transformation of the antenna's intrinsic impedance to the circuit's 50 ohm impedance. At the same time, the entire circuit adopts a dual-frequency filter and amplifier to reduce the complexity of link design, avoid the use of distributed impedance transformation transmission lines, reduce the impact of transmission line radiation on components, and improve electromagnetic compatibility performance.

[0037] Ansys Ansoft Electronic is used to model the antenna model, and the electromagnetic radiation performance, field distribution and electromagnetic scattering parameters are calculated. The actual antenna or microwave circuit system modeling is not limited to Ansys Ansoft Electronics, but can also use other microwave modeling simulation software or microwave simulation tools, such as Dassault Computational Simulation Technology (CST), COMSOL Multiphysics, etc., and can also use programs written based on electromagnetic field numerical algorithms to solve field distribution.

[0038] Design the initial antenna structure, the design principles are:

[0039] 1) Ensure that the dual-band antenna operates in a frequency band as close to 433MHz and 868MHz as possible, and that the simulated antenna The parameters are as small as possible. For wireless transceiver antennas used in the field of Internet of Things, The value is required to be less than -6dB.

[0040] 2) Achieve broadband effect as much as possible, that is, design a wider bandwidth near the working frequency band to meet Less than -10dB. Also, try to achieve as few parasitic bands as possible near the working frequency band to facilitate easy tuning of the subsequent matching circuit.

[0041] 3) The antenna pattern is an intrinsic property of the antenna. At the beginning of the design, it should meet the design requirements. For antennas used in the Internet of Things, their radiation pattern should achieve omnidirectional radiation as much as possible.

[0042] 4) In order to solve the problem of low radiation efficiency of Sub-1GHz electrically small-size antennas, the antenna should be designed to achieve as high radiation efficiency as possible to obtain higher electromagnetic wave energy utilization, and ensure that the electromagnetic wave signal can propagate far enough to achieve excellent wireless transmission performance of receiving and transmitting terminal signals.

[0043] In this embodiment, Ansoft Electronics microwave simulation software is used for antenna design, and synchronous parametric modeling and full-wave electromagnetic wave simulation calculation are performed. After the calculation is completed, the calculation process and simulation results are exported as a VBScript script file using the script recording method, and then optimized using the Matlab language. Antenna design modeling, simulation, result export and post-processing are not limited to Ansoft Electronics. This embodiment uses Ansoft Electronics as an example to introduce the implementation method. The electromagnetic wave field radiation and field distribution use the finite element method (Finite Element Methods) to perform full-wave electromagnetic wave simulation calculation. In actual operation, it is not limited to the use of the finite element method for full-wave simulation calculation, and any other electromagnetic field calculation method can also be used. After the model simulation is completed, select the post-processing tool, export the model file as a vbs file, and record all operation records in the script file. In the script program model, define the parameter information of the model and the optimized electromagnetic variable information.

[0044] By running the program through a pre-set script and calling Ansoft Electronics to perform operations, it can be very efficient and accurate, and can save a lot of repetitive operations. This method is very suitable for using third-party algorithms to call scripts to achieve parameter optimization design of complex microwave system models and microwave system models that require more calculated variables. Then, through other computer languages, the vbs script language is called to achieve automatic modeling and optimization of antennas or other microwave systems. In this embodiment, the Matlab language is used to call the vbs script. This embodiment provides a calling method, which is not limited to the Matlab language in the specific implementation process.

[0045] The external function calling process is: initialize the antenna model design, set the electromagnetic wave radiation and solve the boundary conditions, design the antenna structure and working frequency band, set the antenna excitation port, use the finite element method to calculate and solve the antenna radiation pattern, export the vbs script program, use the Matlab language to call the vbs script program, calculate the electromagnetic field distribution, use the set optimization algorithm according to the calculation results, realize the antenna structure design with the best performance, return the calculation results to the model variables, export the antenna structure information, close the Matlab language file, and realize the final model solution. Figure 1The antenna matching circuit design flow chart based on this embodiment is shown.

[0046] When the antenna pattern, directional gain and electromagnetic scattering parameters meet the design requirements, the antenna’s The parameters are S1P files, which store the electromagnetic parameter information of the antenna. Currently, mainstream commercial software on the market supports reading electromagnetic scattering parameter information in S1P parameter format. The electromagnetic field simulation software is used to read the initial electromagnetic scattering parameter information of the antenna without a matching circuit.

[0047] As shown in Figure 2. The antenna feeding point involved in this embodiment is located at the zero point of the x-axis. The area where x>0 is the ground plane of the antenna, and the area where x<0 is the radiation arm of the antenna. The inverted PIFA structure is used to achieve dual-band radiation, improve bandwidth, and achieve higher radiation efficiency. This embodiment provides an antenna structure design method, but in actual application scenarios, it is not limited to the antenna design method of this form. Any antenna structure can also be used to achieve effective radiation of electromagnetic waves to meet design requirements. As shown in Figure 3, the original antenna structure based on the antenna involved is shown in Figure 3. Parameter information. Its operating frequency band is not within the design requirements of 433MHz and 868MHz, so it is necessary to use a matching circuit loading method to coordinate the working frequency band of the antenna to the required frequency band.

[0048] Figure 4 The 433MHz antenna radiation pattern is shown. Figure 5 The radiation pattern of the 868MHz antenna is shown. The radiation pattern is the physical property of the antenna radiation and will not change due to the introduction of the matching circuit. The antenna radiation pattern in this embodiment meets the radiation requirements of the omnidirectional antenna to achieve omnidirectional reception and transmission of signals by the wireless transceiver system for the UHF band.

[0049] like Figure 6 The matching circuit 1 and the matching circuit 2 shown in the figure use discrete components. The capacitance, inductance and resistance values ​​are optimized appropriately to tune the resistance, capacitance and inductance characteristics of the circuit to achieve the adjustment of the resonant frequency. For the mode search optimization algorithm, there is no need to find the derivative of the calculated function, so it is particularly suitable for solving the extreme value of unconstrained optimization problems in random parameters. For complex matching circuit design, since there are many components involved and each component affects each other, the mode search method is used to optimize the optimal component combination that can match the circuit. The form of all matching circuits is not limited, and π-type, L-type, or any other form of matching circuit design can be used. In the matching circuit design, the components used include capacitors, inductors, resistors, attenuators, diodes, transistors, amplifiers, couplers, power dividers, bridges and filters.

[0050] The purpose of the second matching circuit is to achieve impedance matching from the back end of the circuit to the input end of the module. Type circuit matching method.

[0051] In this embodiment, the optimization design is mainly aimed at circuit 1 to achieve the matching between the antenna end and the circuit input end. In this embodiment, N-level matching circuits are used. In each set of matching circuits, the capacitance values ​​of the optimized capacitor components are set to C1, C2, ..., C N , the unit is set to picofarad ( ); Set the inductance value of the optimized inductor components to L1, L2...L N (Unit is set to nanohenry ), the resistance values ​​of the optimized resistor components are set to R1, R2...R N (Units are set in ohms ). All capacitors, resistors, and inductors correspond to A vector direction.

[0052] As shown in Figure 6, in the matching circuit, for each component position, capacitors, inductors, and resistors are used to represent them, and they can be randomly replaced during the optimization process, and their values ​​can also be continuously optimized to continuously obtain more optimized calculation results. And the corresponding component type at any position is not fixed, and the corresponding component type can be capacitors, inductors, or resistors, and the size can be adjusted at will to achieve the best matching effect.

[0053] At the antenna feed port, set the initial values ​​of capacitor C0, inductor L0, and resistor R0 to load the initial circuit. In the theoretical design, the matching circuit adopts a multi-stage method of parallel and series connection, and the components at each position can be replaced with capacitors, inductors, and resistors. The multi-stage cascade method can achieve a wider matching bandwidth, but at the same time it will bring greater energy loss to the RF link. Fewer cascades result in poorer matching performance, but less impact on system loss.

[0054] This embodiment adopts Figure 6 In Type circuit matching method. A total of three matching circuits are used, using parallel capacitors and series inductors. The signal input from the antenna end is connected to the corresponding module end through the matching circuit, filter, amplifier, and then connected to the corresponding module end to realize signal collection and transmission. The circuit system uses dual-frequency amplifiers and filters that meet both the 433MHz and 868MHz frequency bands. The link system adopts a one-way dual-frequency design method, replacing the commonly used two-way transceiver system design method, saving the overall design cost of the RF transceiver system.

[0055] Matching circuit 1 and matching circuit 2 can also be connected to any one or more of couplers, filters, attenuators, diodes, triodes and power dividers other than filters and amplifiers, which are used to realize the components of the radio frequency circuit transceiver function. The purpose of matching circuit 1 is to achieve matching from the front-end signal input to the circuit, and matching circuit 2 is to achieve matching from the circuit input to the transceiver chip at the back end.

[0056] In this embodiment, the parameter variation range capacitance is [1pF, 300pF], the inductance is [0nH, 300nH], the resistance is [0Ω, 200Ω], and the design optimization step is 1. In this embodiment, based on the designed antenna initial frequency band operating near 433MHz, 700MHz and 900MHz, a three-level matching method is adopted to achieve the tuning of the dual-frequency resonant frequency of the transceiver system. For each optimized discrete device, it is set to [x1, x2, x3, x4, x5, x6, x7, x8, x9]. There are 9 optimized elements, corresponding to 9 optimized vector directions. Set the shrinkage factor is 0.25, and the calculation convergence error limit is set to , that is, when the error between two consecutive calculations obtained by optimization is less than 0.001, the optimization is stopped and the optimal solution is given.

[0057] The optimization goal of the optimal solution is set as .in, and The corresponding electromagnetic scattering at 433MHz and 868MHz respectively Parameter value, and They are the corresponding operating bandwidths at 433MHz and 868MHz respectively. are weight coefficients of the corresponding optimized values. Right now ,symbol To take the absolute value.

[0058] In this optimization scheme, the larger G value corresponds to , , , The comprehensive result after weighing. For the optimization result, we tend to choose the maximum Value. Larger value, corresponding to a larger , i.e. the smaller (because is a negative value less than 0), and corresponds to a larger bandwidth. The larger the coefficient value, the optimization process will tend to select variables with larger coefficient weights. In this embodiment, since the intrinsic bandwidth of the antenna is narrow at 433MHz, a larger coefficient is selected. , which is 0.35. The antenna has a wide bandwidth at 868MHz and a smaller , so its coefficient and bandwidth factor Select a smaller value.

[0059] The working frequency band of 433MHz is 433.05MHz~434.7HMz (with 1.65MHz bandwidth), and the corresponding frequency range of 868MHz band is 863MHz~870HMz (with 7MHz bandwidth), so in the optimization process, A weight coefficient of 0.05 was selected and set The weight coefficient is 0.1, which will result in a larger bandwidth optimization result in the 868MHz frequency band. Since the electromagnetic scattering parameter is a very important indicator for the UHF working frequency band, the electromagnetic scattering parameter is used in the optimization process. is assigned a larger weight coefficient.

[0060] With the first parameter As the benchmark, the step length is Optimize until the boundary range of the corresponding values ​​of capacitance, inductance, and resistance is optimized. For each corresponding value, calculate the corresponding electromagnetic scattering parameters of the corresponding antenna after the matching circuit is loaded. If the specified parameters are optimized The boundary of If the value is the minimum, then exit The optimization of the base vector is performed with the second parameter Based on the optimization, the mode is moved. If it is within the boundary range, select The minimum position of the vector basis corresponding to the reference, that is, the corresponding .by As a benchmark, Corresponding As the starting point, proceed with the second parameter The optimization based on the benchmark is the mode shift. For the calculation of this step, if The corresponding minimum value of electromagnetic scattering parameters and the initial value obtained by the first mode shift The absolute value of the difference , then in the second optimization process, the calculation step size is Multiply by the shrink factor, which is set to , and conduct the second round of optimization calculations.

[0061] By analogy, all dimensions are solved and calculated, that is, all vector directions are optimized. In this implementation, there are 9 elements in total, so there are 9 vector directions in total. In the physical sense, in order to achieve the value search for the capacitor, inductor, and resistor corresponding to each position, until the minimum and second minimum values ​​are found. , stop the calculation and get the corresponding optimal solution.

[0062] The device values ​​used in this embodiment are as follows: Device 1 capacitor , Device 2 resistance Component 3 Inductor ; Component 4 capacitor , Component 5 Resistor ; Component 6 resistor ; Components 7 Capacitor , Components 8 Resistors , Components 9 Inductor .

[0063] Return the parameter values ​​corresponding to the optimal solution obtained by optimization to the circuit settings. According to the obtained capacitance, inductance, and resistance values, reverse matching circuit modeling is performed to achieve the final matching in the 433MHz and 868MHz operating frequency bands. Parameters such as Figure 7 As shown. According to the matching effect, the original intrinsic working frequency band of the antenna is located near 425MHz, 760MHz, and 990MHz. After loading the matching circuit, the resonant center resonant frequency band of the wireless transceiver system after loading the antenna is located near 43MHz and 868MHz. After loading the matching RF circuit, the three-frequency resonant frequency band of the antenna becomes a dual-frequency working frequency band that meets the working frequency band requirements. , at 433MHz and 868MHz, the original -4.7dB and -15dB are added to the matching circuit, and the overall circuit It becomes -20.1dB and -8.3dB after tuning. For the UHF working band where the 433MHz and 868MHz bands are located, the requirements of the RF transceiver link system are met.

[0064] Verify the radiation efficiency after loading the matching circuit. Figure 8As shown in the figure, after loading the matching circuit, the radiation efficiency at 433MHz is 31.2%, and the gain is -3.1dBi; the radiation efficiency at 868MHz is 58.5%, and the gain is 1.2dBi. After loading the matching circuit, the actual test shows that the radiation efficiency at 433MHz is 0.21%, and the gain is -1.14dBi; the radiation efficiency at 868MHz is 30%, and the gain is -0.57dBi. In this implementation, after loading the matching circuit, the overall system Parameters, as well as the system transceiver efficiency, effectively meet the UHF band link transceiver system index requirements.

[0065] Embodiment 2: 868MHz frequency band circuit matching

[0066] Based on Example 1, a single-frequency wireless transceiver system operating in the 868MHz frequency band (corresponding to a frequency range of 863MHz~870HMz) is designed. As shown in Figure 9, the antenna is grounded based on the monopole antenna technology and uses an inverted PIFA three-dimensional structure antenna to achieve a relatively wide operating bandwidth in the 868MHz frequency band. After the design is completed, it can be seen from Figure 10 that the intrinsic operating frequency of the antenna is near 1GHz. Near the 1GHz center frequency, The bandwidth of 200MHz is below -6dB. Based on this antenna feature, a first-level matching circuit is used to adjust the antenna circuit matching and resonance point.

[0067] Using the matching circuit design method shown in Figure 6, the matching circuit is loaded at the antenna receiving end, and the module is connected during the loading of the filter and amplifier to realize signal reception and transmission. Type matching circuit design method. Use capacitors ,resistance ,inductance to load.

[0068] Will , and As the optimized variable, the value range of the three elements is set to , , The three elements are regarded as three vector directions, and the pattern search method is used to perform numerical optimization for each vector direction. Referring to the first embodiment, since the original antenna itself has a small and a larger bandwidth, and its bandwidth near 1GHz far exceeds the required bandwidth of 863MHz~870HMz. Therefore, the optimization function adopts , tend to get better value.

[0069] Based on implementation 1, perform iteration and convergence to determine the capacitance ,resistance and The calculation result is returned to the circuit system for link simulation to obtain the optimized As shown in Figure 11.

[0070] The automated circuit matching method based on pattern search in this implementation is faster and more efficient than the traditional RF link design method. More importantly, this method can try optimization multiple times within the required frequency band, change the weight function, and obtain the optimal solution.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatic matching design of radio frequency circuits based on an optimization algorithm, characterized in that: The following steps are involved: a. Build a simulation model of the RF system or antenna and obtain its electromagnetic scattering parameters; b. Design one or more matching circuit models and set the value ranges of capacitors, inductors and resistors; c. Use optimization algorithms to optimize the parameters of components in the matching circuit to automatically optimize the matching performance of the RF circuit; d. The circuit value obtained through automatic optimization is loaded into the actual circuit of the RF circuit or antenna to achieve tuning of the operating frequency band of the system or antenna; In step c, the parameters of capacitance, inductance and resistance are randomly replaced during the optimization process, and their values ​​can be continuously optimized to continuously obtain more optimized calculation results; and the corresponding component type at any position is not fixed, and the corresponding component type is capacitance, inductance or resistance, and the size can be adjusted at will to achieve the best matching effect; A simulation model of a radio frequency system or antenna is constructed through simulation software. The operation process performed by the simulation software is to initialize the antenna model design, set electromagnetic wave radiation and solve boundary conditions, design the antenna structure and working frequency band, set the antenna excitation port, use the finite element method to calculate and solve the antenna radiation pattern, export the vbs script program, use the Matlab language to call the vbs script program, calculate the electromagnetic field distribution, use the set optimization algorithm according to the calculation results, realize the antenna structure design with the best performance, return the calculation results to the model variables, export the antenna structure information, close the Matlab language file and realize the final model solution.

2. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 1, characterized in that: The matching circuit model adopts a multi-stage method of parallel and series connection, and the components at each position are replaced by capacitors, inductors or resistors.

3. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 1, characterized in that: The radio frequency system includes an antenna, a matching circuit 1, a matching circuit 2 and a module which are electrically connected in sequence. Matching circuit 1 is used to achieve multi-band circuit performance matching, realize the transformation of the intrinsic impedance of the antenna to the 50 ohm impedance of the circuit, and realize the matching from the front-end signal input to the circuit; Matching circuit 2 is used to achieve impedance matching from the back end of the circuit to the input end of the module; The first matching circuit and the second matching circuit adopt a π-type or L-type circuit.

4. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 3, characterized in that: In the radio frequency system, any one or more of a filter, an amplifier, a coupler, a filter, an attenuator, a diode, a triode and a power divider are connected between the matching circuit 1 and the matching circuit 2 to realize the transceiver function of the radio frequency circuit.

5. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 2 or 3, characterized in that: Matching circuit 1 and matching circuit 2 use separate components, and the values ​​of capacitors, inductors and resistors are optimized to tune the resistance, capacitance and inductance characteristics of the circuits to achieve adjustment of the resonant frequency.

6. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 1, characterized in that: The simulation software uses Ansys Ansoft Electronic, Dassault Computational Simulation Technology or COMSOL Multiphysics simulation software to model the antenna or radio frequency circuit model, and calculate the electromagnetic radiation performance, field distribution and electromagnetic scattering parameters.

7. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 1, characterized in that: The optimization algorithm is a pattern search algorithm, a conjugate gradient method, a Newton method, a square method, a genetic algorithm, an ant colony algorithm, a particle swarm algorithm, a simulated annealing algorithm or a neural network algorithm.

8. The method for automatic matching design of radio frequency circuit based on optimization algorithm according to claim 6, characterized in that: By writing a numerical calculation algorithm, the field distribution and electromagnetic scattering parameters of the antenna are obtained.

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