A radio frequency power amplifier with load impedance detection function and a detection method

Abstract

The application relates to the field of radio frequency power amplifier design, in particular to a radio frequency power amplifier with a load impedance detection function and a detection method. The radio frequency power amplifier comprises an input matching network IMN, an input end of the input matching network IMN is connected with a radio frequency input signal RF; a radio frequency power tube PA, an input end of the radio frequency power tube PA is connected with an output end of the input matching network IMN; an output matching network OMN, an input end of the output matching network OMN is connected with an output end of the radio frequency power tube PA, an output end of the output matching network OMN is connected with a load, and the output matching network OMN comprises a first sampler group S1, a second sampler group S2 and a third sampler group S3. Through the cooperative architecture of the input matching network IMN, the radio frequency power tube PA and the output matching network OMN, efficient amplification of the radio frequency signal and real-time detection of the load impedance are realized. The architecture does not need an additional detection module, the system complexity is significantly reduced, and the reliability and integration of the power amplifier are improved.

Description

Technical Field

[0001] The present application relates to the field of radio frequency power amplifier design, and in particular to a radio frequency power amplifier with a load impedance detection function and a detection method. Background Art

[0002] With the evolution of wireless communication technology, next-generation radio systems are increasingly reliant on phased arrays and multiple-input, multiple-output (MIMO) systems, driven by their significant advantages in spatial power combination. However, in phased array applications, dynamic changes in scanning angle can alter the coupling characteristics between array elements, directly leading to dynamic fluctuations in the antenna drive-point impedance. Furthermore, load impedance fluctuations are common in mobile devices (such as cell phones), RF plasma generation equipment, and medical applications such as RF tumor ablation.

[0003] As a core component in the RF transmit chain, the impedance matching of the power amplifier significantly impacts its performance. Dynamic changes in load impedance not only reduce output power and efficiency, but also threaten system stability. Furthermore, mismatched loads distort the nonlinear characteristics of the power amplifier, causing linearity degradation. While digital pre-distortion (DPD) technology can partially compensate for these issues, its effective implementation requires accurate load impedance information.

[0004] Existing power amplifiers face performance compensation drawbacks such as high cost, high losses, and poor integration when faced with dynamic changes in load impedance. For example, existing technologies install isolators between the power amplifier and the load, leveraging the isolator's unidirectional transmission characteristics to mitigate the effects of mismatch. However, this solution introduces additional losses and increases the size and cost of the transmitter, making it difficult to adapt to applications such as phased arrays that require stringent integration and lightweight design. Research and development of load monitoring and control technologies, typically including mixer-based complex impedance measurement solutions and directional coupler-based load sensing methods, are also underway. However, inserting devices such as cascaded couplers into the RF signal path inevitably increases circuit losses and hardware size, contradicting the design requirements of miniaturization and efficiency. Summary of the Invention

[0005] In order to solve the problem that the power amplifier lacks a suitable load impedance detection function, the present application provides a radio frequency power amplifier with a load impedance detection function and a detection method.

[0006] In a first aspect, the present application provides a radio frequency power amplifier with load impedance detection function, comprising: an input matching network IMN, an input end of the input matching network IMN being connected with a radio frequency input signal RF; a radio frequency power tube PA, an input end of the radio frequency power tube PA being connected with an output end of the input matching network IMN; and an output matching network OMN, an input end of the output matching network OMN being connected with an output end of the radio frequency power tube PA, an output end of the output matching network OMN being connected with a load, the output matching network OMN comprising a first sampler group S1, a second sampler group S2 and a third sampler group S3.

[0007] By adopting the above technical solution, the input matching network IMN, the radio frequency power tube PA and the output matching network OMN are cooperatively arranged to realize efficient amplification of the radio frequency signal and real-time detection of the load impedance. The input matching network IMN can optimize the signal transmission efficiency and reduce the reflection loss; the radio frequency power tube PA provides stable gain; and the output matching network OMN integrates the samplers, which can convert the radio frequency signal that cannot be directly measured into detectable electrical parameters, thereby laying a foundation for accurate measurement of the load impedance. The architecture does not need additional detection modules, significantly reduces the system complexity and improves the reliability and integration of the power amplifier.

[0008] In a specific implementation, the first sampler group S1 is connected with a main transmission line of the output matching network OMN and is connected between the radio frequency power tube PA and a direct current bias circuit of the output matching network OMN, the direct current bias circuit being connected with a power supply and being grounded through a capacitor; the second sampler group S2 is connected with the main transmission line and is connected between the direct current bias circuit and the load; and the third sampler group S3 is connected with a short circuit line of the output matching network OMN.

[0009] By adopting the above technical solution, the spatial layout design of the three samplers realizes signal collection at different positions of the output matching network OMN. The first sampler group S1 is close to the radio frequency power tube PA and can detect the initial reflected signal; the second sampler group S2 is located at the load side and reflects the final load matching state; and the third sampler group S3 samples through the short circuit line and provides additional phase information. The multi-position sampling forms complementary data, enhances the sensing ability of the system to the complex load change, and greatly improves the comprehensiveness and accuracy of the impedance detection.

[0010] In a specific implementation, the first sampler group S1, the second sampler group S2 and the third sampler group S3 comprise a plurality of samplers, and the samplers comprise a diode detector D, a coupling capacitor C coup , a coupling resistor R coup , a filter capacitor C1, a filter capacitor C2 and an isolation resistor R ISOAnd DC resistance R DC .

[0011] By adopting the above technical solution and utilizing the nonlinear characteristics of the diode, high-precision detection of RF signals can be achieved. coup With coupling resistor R coup The combination of can flexibly adjust the detection sensitivity, and the filter circuit effectively filters out high-frequency noise, ensuring that the output DC voltage accurately reflects the amplitude change of the RF signal. This design maintains good linearity and dynamic range within a wide frequency band and is suitable for a variety of RF application scenarios. In a specific implementation scheme, the signal input end of the sampler is connected to the coupling capacitor C coup The first end of the coupling capacitor C coup The second end is connected to the coupling resistor R coup The first end of the coupling resistor R coup The second end of the isolation resistor R ISO The first end of the filter capacitor C1 is connected to the coupling resistor R coup The second end of the filter capacitor C1 is grounded; the cathode of the diode detector D is connected to the isolation resistor R ISO The first end of the filter capacitor C2 is connected to the isolation resistor R ISO The second end of the filter capacitor C2 is grounded; the DC resistor R DC The first end is connected to the isolation resistor R ISO Between the second end of the sampler and the signal output end, the DC resistor R DC The second end is grounded.

[0012] By adopting the above technical solution, the coupling capacitor C coup , coupling resistor R coup The specific connection method with the diode detector ensures effective coupling of the RF signal while preventing the effects of DC bias on the detection circuit. The parallel design of the filter circuit further smooths the detection signal, reduces ripple interference, and improves the stability of the DC voltage output. This circuit is compact, easy to integrate, and has strong anti-interference capabilities, ensuring reliable operation in complex electromagnetic environments.

[0013] In a specific implementation scheme, the output matching network OMN is in a linear relationship, and the standing waves corresponding to the samplers, as well as the standing waves and the voltage reflected waves and incident waves of the load are in a linear relationship.

[0014] By employing this technical solution, the linear characteristics of the output matching network (OMN) ensure a stable linear relationship between the standing wave signal at each sampling point and the reflected and incident waves from the load, providing a theoretical basis for subsequent mathematical modeling. This characteristic transforms complex RF impedance detection problems into a system of linear equations, significantly simplifying the calculation process and improving detection speed and accuracy. This design avoids the iterative calculations of traditional nonlinear models, reduces system computing power requirements, and is suitable for real-time monitoring applications.

[0015] In a specific feasible implementation scheme, in the output matching network OMN, the electrical length of the line segment set at one end of the RF power tube PA is Φ1, the electrical length of the line segment set at one end of the load is Φ2, the electrical length of the line segment corresponding to the first sampler group S1 is θ1, the electrical length of the line segment corresponding to the second sampler group S2 is θ2, and the electrical length of the line segment corresponding to the third sampler group S3 is θ3.

[0016] By employing this technical solution and properly setting the electrical length of each line segment, the transmission phase and amplitude distribution of the RF signal in the output matching network (OMN) can be precisely controlled. This specific electrical length design enables the sampler to capture signal characteristics at the optimal location, optimizing detection sensitivity and resolution. This parameter design also suppresses harmonic interference, improves the spectral purity of the power amplifier, and enhances overall performance.

[0017] In a specific implementation scheme, the output matching network OMN includes a first branch and a second branch. The inductive reactance of the first branch is B1, and the inductive reactance of the second branch is B2.

[0018] By adopting this technical solution, the dual-parallel-stub inductive reactance design provides flexible impedance matching capabilities, allowing dynamic adjustment of matching network parameters for varying load characteristics. This design enhances the power amplifier's adaptability to load changes, broadens its operating bandwidth, and reduces power reflections in mismatched conditions, improving energy transmission efficiency and extending the life of the power tubes.

[0019] In the second aspect, the present application also provides a detection method, including: collecting the DC voltage output by each sampler and calculating the voltage ratio; based on the linear characteristics of the output matching network OMN, combined with the voltage ratio, establishing a complex plane circle equation; based on the complex plane circle equation, finding the intersection points of each circle and determining the standing wave ratio; mapping the standing wave ratio to the complex reflection coefficient plane, and calculating the load reflection coefficient and impedance.

[0020] By adopting the technical scheme, the detection method converts the radio frequency impedance detection into mathematical model solving by collecting the voltage ratio and combining the linear characteristics of the output matching network (OMN), and realizes the non-intrusive measurement of the load impedance. The establishment and solving process of the complex plane circle equation intuitively presents the impedance characteristics by using the geometric method, avoids the direct measurement of complex physical quantities, and reduces the detection difficulty. The application of the short open load method further calibrates the system error and improves the measurement accuracy, so that the method is suitable for the impedance monitoring and adaptive matching control of various radio frequency power amplifiers.

[0021] In a specific implementable scheme, the establishing the complex plane circle equation comprises: collecting the sampling voltage under each load, and fitting an ellipse on the complex reflection coefficient plane; and calculating the parameters of the complex plane circle equation according to the ellipse coefficients.

[0022] By adopting the technical scheme, the sampling voltage and the standing wave ratio are associated, an ellipse is fitted on the complex reflection coefficient plane, and is converted into a circle equation, so that effective conversion from discrete sampling data to continuous mathematical model is realized. The method fully utilizes the linear characteristics of the output matching network (OMN), maps the multi-dimensional impedance parameters to a two-dimensional plane, simplifies the calculation complexity while retaining the key information. The accurate calculation of the circle equation parameters ensures the accuracy of the subsequent impedance solving, and provides a reliable basis for the load characteristic analysis.

[0023] In a specific implementable scheme, the calculating the load reflection coefficient comprises: determining the bilinear transformation of the standing wave ratio to the complex reflection coefficient plane by the short open load method.

[0024] By adopting the technical scheme, the bilinear transformation maps the standing wave ratio to the complex reflection coefficient plane, realizes the conversion from scalar measurement to complex parameter, and completely characterizes the amplitude and phase characteristics of the load impedance. The calculation method of the complex reflection coefficient circle radius directly solves the reflection coefficient by using the geometric relationship, avoids complex algebraic operation, and improves the calculation efficiency. The method maintains good linearity and resolution in a wide impedance range, can quickly respond to load changes, and meets the real-time monitoring demand.

[0025] In summary, the present application has at least one of the following beneficial effects: the present application obtains the standing wave signals at different positions of the output matching network (OMN) by the multi-position sampler layout, forms complementary detection data. Combined with the linear characteristics of the output matching network (OMN) and the complex plane circle equation solving method, the complex radio frequency signal is converted into a calculable mathematical model, and the error accumulation caused by nonlinear factors in the traditional detection method is avoided. This detection method can quickly and accurately capture the slight changes of the load impedance, and can realize high-precision detection whether it is a static load or a dynamically changing load. Based on the detection result, the system can adjust the power amplifier parameters in time, optimize the power transmission efficiency, reduce the energy loss caused by mismatch, and ensure the stable and efficient operation of the equipment.

[0026] This application integrates the sampler into the output matching network OMN. Through parallel coupling and a specific layout design, the addition of the sampler does not affect the size of the original RF circuit. This highly integrated design not only reduces the space occupied by the external detection circuit, but also avoids the signal interference introduced by the additional modules, improving the stability and reliability of the system. At the same time, this architecture can adapt to a variety of RF power amplifier types and different frequency band application scenarios without the need for large-scale modification of the original circuit, significantly enhancing the compatibility and versatility of the solution and reducing the cost of equipment upgrades.

[0027] This application uses a sampler and basic circuit components with a simple structure and low cost. The detection method is based on linear network theory and geometric solution, which avoids complex numerical calculations and iterative processes. It has low requirements on system computing power, and ordinary processors can achieve fast calculations, further saving equipment resources. In addition, the circuit design and algorithm flow of this solution are easy to understand and implement, and engineering personnel can master it without complex training. In the application scenarios of RF power amplifiers such as communication base stations, radar equipment, and mobile terminals, it can be quickly deployed, effectively shortening the R&D cycle, and has extremely high engineering application value and promotion potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural diagram of a radio frequency power amplifier with a load impedance detection function provided in an embodiment of the present application.

[0029] Figure 2 This is another structural diagram of a radio frequency power amplifier with a load impedance detection function provided in an embodiment of the present application.

[0030] Figure 3 It is a structural diagram of the sampler provided in an embodiment of the present application.

[0031] Figure 4 It is a flow chart of a detection method provided in an embodiment of the present application.

[0032] Figure 5 It is a planar schematic diagram of the complex plane circle equation provided in an embodiment of the present application.

[0033] Figure 6 This is a signal diagram of a radio frequency power amplifier with a load impedance detection function provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The terms used in the following examples of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification of the present application, the singular expressions "a", "an", "above", "the", and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present application refers to any or all possible combinations of one or more of the listed items.

[0035] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0036] The following will provide a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0037] See also Figure 1 and Figure 2 , Figure 1 A schematic structural diagram of a radio frequency power amplifier with a load impedance detection function according to an embodiment of the present application is provided. Figure 2 Another structural schematic diagram of a radio frequency power amplifier is provided.

[0038] like Figure 1 and Figure 2 As shown, the RF power amplifier with load impedance detection function includes: an input matching network IMN, the input end of the input matching network IMN is connected to the RF input signal RF; an RF power transistor PA, the input end of the RF power transistor PA is connected to the output end of the input matching network IMN; an output matching network OMN, the input end of the output matching network OMN is connected to the output end of the RF power transistor PA, and the output end of the output matching network OMN is connected to the load, and the output matching network OMN includes a first sampler group S1, a second sampler group S2 and a third sampler group S3.

[0039] In this embodiment, the input matching network (IMN) is a passive network located between the RF input signal and the power transistor. It is used to convert the source impedance of the RF input signal into the optimal impedance at the input of the RF power transistor (PA), ensuring efficient signal transmission to the power transistor. Furthermore, the input matching network (IMN) suppresses noise and harmonic interference outside the operating frequency band of the power amplifier.

[0040] In the present embodiment, the RF input signal RF refers to a high-frequency AC signal that is input to the power amplifier. The RF input signal serves as the original signal source to be amplified, and the frequency and power of the RF input signal meet the operating range of the power amplifier.

[0041] In the present embodiment, the RF power transistor PA refers to a core active device, a high-power transistor. The RF power transistor PA is used to amplify the input low-power RF signal to the required high power level and convert DC bias energy into RF output energy.

[0042] In this embodiment, the output matching network (OMN) refers to an impedance matching network with integrated sampling functionality. The OMN is used to convert the high output impedance of the power tube to the standard impedance of the load, maximizing power transmission efficiency and enabling real-time monitoring of the load impedance through a built-in sampler.

[0043] Based on the above embodiment, as another optional embodiment, the load is a variable load (VariableLoad).

[0044] In some embodiments, the output matching network OMN may further include an impedance matching capacitor C match , impedance matching resistor R match , impedance matching capacitor C match , impedance matching resistor R match Connected in series between the main transmission line and the load of the output matching network OMN.

[0045] The collaborative architecture of the present invention's input matching network (IMN), RF power transistor (PA), and output matching network (OMN) enables efficient amplification of RF signals and real-time detection of load impedance. The IMN optimizes signal transmission efficiency and reduces reflection loss; the PA provides stable gain; and the OMN integrates a sampler to convert directly measurable RF signals into detectable electrical parameters, laying the foundation for accurate load impedance measurement. This architecture eliminates the need for additional detection modules, significantly reducing system complexity and improving the reliability and integration of the power amplifier.

[0046] Based on the above embodiment, as another optional embodiment, the first sampler group S1 is connected to the main transmission line of the output matching network OMN, and is connected between the RF power tube PA and the DC bias circuit (Bias) of the output matching network OMN. The DC bias circuit is connected to the power supply and grounded through a capacitor; the second sampler group S2 is connected to the main transmission line, and is connected between the DC bias circuit and the load; and the third sampler group S3 is connected to the short-circuit line of the output matching network OMN.

[0047] The first sampler group S1 detects the standing wave in the first section of the main transmission line. The standing wave is formed by the interaction between the output impedance of the power tube and the network. The first sampler group S1 can be used to capture the high impedance fluctuation near the power tube and is sensitive to load changes.

[0048] The second sampler group S2 detects the mixed standing wave in the middle section of the main transmission line, which is affected by the impedance of the two stubs. The second sampler group S2 can reflect the intermediate state of impedance transformation and balance the near- and far-end information.

[0049] The third sampler group S3 detects a pure standing wave on the short-circuit line, which is formed by the load reflection wave. The third sampler group S3 can directly respond to the load reflection characteristics and is most sensitive to the change of the final impedance.

[0050] By deploying samplers in partitioned locations, the present invention builds a full-path standing wave monitoring system within the output matching network (OMN). A first sampler group (S1) is deployed near the output to capture the coupling effects of power tubes, a second sampler group (S2) is deployed midway to monitor the impedance transformation process, and a third sampler group (S3) is deployed far away to track direct reflections from the load. Multi-location sampling generates complementary data, enhancing the system's ability to detect complex load variations and significantly improving the comprehensiveness and accuracy of impedance detection.

[0051] refer to Figure 3 Based on the above embodiment, as another optional embodiment, the first sampler group S1, the second sampler group S2, and the third sampler group S3 include multiple samplers, each of which includes a diode detector D, a coupling capacitor C coup , coupling resistor R coup , filter capacitor C1, filter capacitor C2, isolation resistor R ISO And DC resistance R DC .

[0052] The signal input of the sampler is connected to the coupling capacitor C coup The first end of the coupling capacitor C coup The second end is connected to the coupling resistor R coup The first end of the coupling resistor R coup The second end of the isolation resistor R ISO The first end of the filter capacitor C1 is connected to the coupling resistor R coup The second end of the filter capacitor C1 is grounded; the cathode of the diode detector D is connected to the isolation resistor R ISO The first end of the filter capacitor C2 is connected to the isolation resistor R ISO The second end of the filter capacitor C2 is grounded; the DC resistor R DC The first end is connected to the isolation resistor R ISO Between the second end and the signal output end of the sampler, the DC resistance RDC The second end is grounded.

[0053] In this embodiment, a sampler refers to a signal acquisition unit embedded in the output matching network (OMN) and is used to extract the amplitude information of the RF standing wave. The sampler converts RF energy into a DC voltage, and the load reflection coefficient is calculated by comparing the voltages at multiple sampling points. The sampler can be a square-law detector, whose output voltage is proportional to the square of the standing wave amplitude.

[0054] The diode detector D can be a Schottky diode. Schottky diodes have low power consumption, zero bias detection capability, and a small size of 0201 package. Specifically, the size of the 0201 package is 0.6 mm × 0.3 mm. The coupling capacitor C coup For DC blocking, coupling resistor R coup Used to adjust and further reduce coupling.

[0055] Specifically, the filter capacitor C1 is used to attenuate the harmonics coupled from the output of the power amplifier. The self-resonant frequencies of the filter capacitors C1 and C2 are the second harmonic frequency and the fundamental frequency, respectively, to provide a filtering effect. ISO is selected to be large enough to ensure that the RF signal on the detector is isolated from the filter capacitor C2, and the isolation resistor R ISO The size of the DC resistor R DC Small by several orders of magnitude so that as much of the detector output as possible appears at the DC resistance R DC Both ends.

[0056] Coupling capacitor C coup , coupling resistor R coup The specific connection method with the diode detector D ensures effective coupling of the RF signal while avoiding the influence of DC bias on the detection circuit. The design of filter capacitors C1 and C2 further smoothes the detection signal, reduces ripple interference, and improves the stability of the DC voltage output. The circuit has a compact structure, is easy to integrate, and has strong anti-interference ability, ensuring reliable operation in complex electromagnetic environments. coup It can isolate the power amplifier drain bias voltage from the sampler and only allow AC RF signals to enter the detector. coup The larger the resistance value, the smaller the power coupled to the detector, and the coupling resistor R coup It can work together with capacitors to maintain the stability of the matching network.

[0057] The sampler can use a square law detector to achieve high-precision detection of RF signals by utilizing the nonlinear characteristics of the diode. coup With coupling resistor R coupThe combination of the two allows for flexible adjustment of detection sensitivity, while the filter circuit effectively removes high-frequency noise, ensuring that the output DC voltage accurately reflects changes in the RF signal amplitude. This design maintains excellent linearity and dynamic range across a wide frequency band, making it suitable for a variety of RF applications.

[0058] like Figure 1 As shown, in the embodiment of the present application, the output matching network OMN includes a total of eight samplers, which are represented by digital numbers 1-8, and the output voltages of the eight samplers are represented by V1-V8. The first sampler group S1 may include samplers 1-4, the second sampler group S2 may include sampler 5, and the third sampler group S3 may include samplers 6-8.

[0059] In some embodiments, the RF power amplifier may further include other samplers. The addition of the samplers does not affect the size of the original RF circuit board.

[0060] Based on the above embodiment, as another optional embodiment, the output matching network OMN is in a linear relationship, and the standing waves corresponding to the samplers and the standing waves and the voltage reflected waves and incident waves of the load are all in a linear relationship.

[0061] The output matching network (OMN) is composed of linear passive components, which adhere to the superposition principle. Proportional changes in the input signal result in proportional changes in the output response. Due to its time-invariance, the network parameters of the output matching network (OMN), such as electrical length and susceptance, do not change over time.

[0062] The linear characteristics of the output matching network (OMN) ensure a stable linear relationship between the standing wave signal at each sampling point and the reflected and incident waves from the load, providing a theoretical basis for subsequent mathematical modeling. This characteristic transforms complex RF impedance detection problems into a system of linear equations, significantly simplifying the calculation process and improving detection speed and accuracy. This design avoids the iterative calculations required by traditional nonlinear models, reduces system computing power requirements, and is suitable for real-time monitoring applications.

[0063] like Figure 2 As shown, based on the above embodiment, as another optional embodiment, in the output matching network OMN, the electrical length of the line segment set at one end of the RF power tube PA is Φ1, the electrical length of the line segment set at one end of the load is Φ2, the electrical length of the line segment corresponding to the first sampler group S1 is θ1, the electrical length of the line segment corresponding to the second sampler group S2 is θ2, and the electrical length of the line segment corresponding to the third sampler group S3 is θ3.

[0064] like Figure 2 As shown, based on the above embodiment, as another optional embodiment, the output matching network OMN includes a first branch and a second branch, the inductive reactance of the first branch is B1, and the inductive reactance of the second branch is B2. The second branch is the short-circuit of the output matching network OMN.

[0065] Specifically, the electrical length Φ1 of the line segment at one end of the RF power tube PA in this embodiment refers to the transmission line connecting the first branch to the second branch, which is used to provide initial impedance transformation, match the high output impedance of the power tube, and affect the linear coefficient of all samplers.

[0066] In the embodiment of the present application, the load-side line segment electrical length ψ refers to the total electrical length of the short-circuit line, which is used to form a load-side impedance tuning network, adjust B2 by changing ψ, and determine the standing wave characteristics of the third sampler group S3.

[0067] The electrical length θ1 of the first sampler group S1 is located on the line segment to the left of the Φ1 line segment; the electrical length θ2 of the second sampler group S2 is located on the Φ1 line segment; the electrical length θ3 of the third sampler group S3 is located on the ψ short-circuit branch. Figure 2 , n=1, 2, 3, 4, corresponding to 4 sampling points, namely samplers 1-4; m=6, 7, 8, corresponding to 3 sampling points, namely samplers 6-8.

[0068] By properly setting the electrical length of each line segment, the transmission phase and amplitude distribution of the RF signal in the output matching network (OMN) can be precisely controlled. The specific electrical length design enables the sampler to capture signal characteristics at the optimal location, optimizing detection sensitivity and resolution. This parameter design also suppresses harmonic interference, improves the power amplifier's spectral purity, and enhances overall performance. The dual-parallel branch inductive reactance design provides flexible impedance matching capabilities, allowing dynamic adjustment of matching network parameters for varying load characteristics. This design enhances the power amplifier's adaptability to load changes, broadens the operating bandwidth, reduces power reflections in the event of mismatch, improves energy transmission efficiency, and extends the life of the power tube.

[0069] refer to Figure 4 , Figure 4 The following is a flow chart of a detection method provided by an embodiment of the present application. The detection method is applied to a radio frequency power amplifier with a load impedance detection function. The method can be implemented by a computer program, a single-chip microcomputer, or a system. The computer program can be integrated into a computer device or run as an independent tool application. Specifically, the method includes S100 to S400, and the above steps are as follows:

[0070] S100, collecting the DC voltage output by each sampler and calculating the voltage ratio;

[0071] The sampler in this embodiment of the application is a square law detector, that is, the output voltage value of each sampler is proportional to the square of the input standing wave or input power, that is, . V i is the output DC voltage value of sampler i, b iis the standing wave at sampler i, where i = 1 to 8. Each network corresponding to each sampler position has a sampled b-wave output. The sampled b-wave is the standing wave at each sampling position, i.e., the sum of the forward and reverse traveling waves.

[0072] In this embodiment, the forward traveling wave refers to the electromagnetic wave propagating from the power transistor toward the load, carrying energy to the load, i.e., the incident wave. The reverse traveling wave refers to the electromagnetic wave reflected by the load and propagating toward the power transistor, representing the portion of energy not absorbed by the load, i.e., the voltage reflected wave. The standing wave at the sampling point is the instantaneous vector sum of the forward and reverse traveling waves and directly represents the load impedance change.

[0073] S200, establishing a complex plane circle equation based on the linear characteristics of the output matching network OMN and the voltage ratio;

[0074] Specifically, the output matching network OMN is linearly related to each sampled b wave, and between the sampled b wave and the voltage reflection wave a. L and the incident wave b L There is a linear relationship between them. , so the ratio of any two sampled b waves is proportional to the load reflection coefficient T L There is a linear relationship.

[0075] Samplers 1 and 2 can be selected to determine the target ratio load reflection coefficient T to be solved L ,definition: (1)

[0076] Where b1 is the standing wave of sampler 1, b2 is the standing wave of sampler 2, ω L Defined as the ratio of the standing wave signals of the two samplers in the output matching network OMN, ω L The amplitude and phase of contain the information of load impedance. Based on the square law detection characteristics, through ω L The DC voltage measurement of the sampler can be converted into parameters of the complex reflection coefficient plane, and then the load impedance can be solved. To determine the load reflection coefficient T L , first we need to solve ω L , and then transform it to a flat surface.

[0077] The complex reflection coefficient plane is based on the load reflection coefficient T L is the complex coordinate system of the variable. The real axis is the real part of the load reflection coefficient, and the imaginary axis is the imaginary part of the load reflection coefficient.

[0078] Since the sampled b-waves are linearly related, each b-wave can be represented by b1 and b2: (2)

[0079] Among them, b i is the standing wave of sampler i, i=1~8, Ki and L i is the sampled b i The linear parameters of the output matching network OMN associated with b1 and b2. Equation (2) can be expressed as: (3)

[0080] Depend on , the output voltage ratio of sampler i and sampler 1 is , and formula (3) can be expressed as , we can get the measured sampler output voltage V i With ω L The associated equation is: (4)

[0081] Among them, ω i In the embodiment of the present application, it refers to the coordinates of the center of the sampler i on the complex plane, which is determined by the output matching network OMN structure. ;

[0082] ξ i In the embodiment of the present application, it refers to the signal attenuation coefficient of the output matching network OMN for the sampler i, which is determined by the network topology. .

[0083] Equation (4) describes the equation of a circle on the complex plane, whose center is ω L =ω i , the radius is .

[0084] In formula (2), when i=1:

[0085] We get K1=0,L1=1.

[0086] When i=2:

[0087] We get K2=1, L2=0.

[0088] In formula (4), when i=2:

[0089] Will , Substituting in: ,

[0090] We get ω2=0.

[0091] In formula (4), when i=1:

[0092] because , so i=2 corresponds to the first circle on the complex plane, which has the origin as its center.

[0093] Based on the above embodiment, as another optional embodiment, establishing the complex plane original equation may include: collecting the sampled voltages under each of the loads, and fitting an ellipse on the complex reflection coefficient plane;

[0094] Parameters of the complex plane circle equation are calculated based on the ellipse coefficients.

[0095] Determine the unknown parameter ω i and ξ i The method is to measure the sampler voltage under multiple loads on the circle of the complex reflection coefficient plane, and take (V2 / V1, V i / V1) point to fit the ellipse equation, and then calculate ω based on the coefficient of the i-th ellipse i=3~8 i and ξ i .

[0096] By correlating the sampled voltage with the standing wave ratio, an ellipse is fitted on the complex reflection coefficient plane and converted into a circular equation, effectively transforming discrete sampled data into a continuous mathematical model. This method leverages the linear characteristics of the output matching network (OMN) to map multidimensional impedance parameters onto a two-dimensional plane, simplifying computational complexity while preserving key information. The precise calculation of the circular equation parameters ensures the accuracy of subsequent impedance solutions, providing a reliable basis for load characteristic analysis.

[0097] S300, based on the complex plane circle equation, finding the intersection points of each circle and determining the standing wave ratio;

[0098] refer to Figure 5 , based on the ellipse equation fitting ω i and ξ i (i=3~8), all circles can be drawn on the complex plane, since these circles intersect at ω L , so the standing wave ratio can be solved by their intersection, that is, the complex number ω L .

[0099] Although there are two ω at the intersection of the two circles L value, but due to the load reflection coefficient T of all loads L The values ​​are mapped to the negative imaginary plane of the complex plane, so of the two intersection points that exist, only the one below the real axis is valid. L At least two circles are required; additional circles provide redundancy and improve accuracy.

[0100] refer to Figure 6 Based on the signal flow graph and Mason gain formula, the b-waves of the three sampler regions are calculated as:

[0101] (5)

[0102] (6)

[0103] (7)

[0104] Among them, , Z L is the load impedance, Z0 is the characteristic impedance; the Mason gain formula is a core tool for linear system signal flow graph analysis, used to directly calculate the transfer function from the input node to the output node; n = 1, 2, 3, 4, m = 6, 7, 8. As mentioned above, the b-wave expression can be written as follows: (8)

[0105] Among them, A i and B i is a in formula (5), (6), (7) L and b L Substitute equation (8) into equation (2) and divide it into a L and b L Term, we get the following system of equations:

[0106] (9)

[0107] K i and L i It can be solved from formula (9), and then according to and Calculate ω i and ξ i Expand A according to equations (5) to (7): i and B i Then we get: (10)

[0108] (11)

[0109] (12)

[0110] Among them, n is the signal attenuation coefficient of the first sampler group S1, ζ5 is the signal attenuation coefficient of the second sampler group S2, m is the signal attenuation coefficient of the third sampler group S3. n=1, 2, 3, 4, m=6, 7, 8. i The values ​​are all real numbers, so all the circle centers fall on the real axis of the complex plane.

[0111] Calculate ω according to equations (10) to (12) i and ξ i, and recorded in Table 1 together with the measured values ​​under 6dBm CW PA excitation.

[0112] Table 1 ω i and ξ i Comparison of theoretical and measured values

[0113]

[0114] Among them, ω i is the real coordinate of the complex plane center of sampler i, ξ i (i.e. ζ i ) is the signal attenuation coefficient of sampler i.

[0115] Sampler 2 is a reference point and is not included in the comparison between theoretical and measured values.

[0116] Sampler 3, ω i The error between theory and measurement is +11.9%, ξ i The error between theory and measurement is +33.6%.

[0117] Sampler 4, ω i The error between theory and measurement is +21.8%, ξ i The error between theory and measurement is +58.5%.

[0118] Sampler 5, ω i The error between theory and measurement is +6.1%, ξ i The error between theory and measurement is -23.3%.

[0119] Sampler 6, ω i The error between theory and measurement is -3.3%, ξ i The error between theory and measurement is +1.2%.

[0120] Sampler 7, ω i The error between theory and measurement is +3.8%, ξ i The error between theory and measurement is -9.1%.

[0121] Sampler 8, ω i The error between theory and measurement is -1.6%, ξ i The error between theory and measurement is +14.6%.

[0122] By Omega i Comparison of theoretical and measured results validated the accuracy of the theoretical model. Sampler 5 exhibited an error of only 6.1%, demonstrating that the modeling of the second sampler group S2 was accurate at the midsection. Samplers 6-8 exhibited an error of <4%, indicating that the third sampler group S3 exhibited stable characteristics at the distal short-circuit stub. Samplers 3-4 exhibited an error of >11%, suggesting that the first sampler group S1 may be significantly affected by the microstrip dielectric constant tolerance near the power transistor.

[0123] By ξ i Theoretical and measured comparison, verify the reliability of the linear network assumption, the error of the sampler 6 is only 1.2%, and the linearity of the network is highly stable at the load end. The attenuation error of the sampler 3-4 is >33%, which may be caused by the near-end welding parasitic capacitance of the power tube.

[0124] According to the values of ω i And ξ i The corresponding circle of each sampler can be drawn on the complex plane, and the intersection of the negative virtual plane is ω L .

[0125] S400, map the standing wave ratio to the complex reflection coefficient plane, calculate the load reflection coefficient and impedance;

[0126] On the basis of the above embodiment, as another optional embodiment, calculating the load reflection coefficient can include: determining the bilinear transformation of the standing wave ratio to the complex reflection coefficient plane by the short circuit open circuit load method;

[0127] Specifically, the bilinear transformation formula of the standing wave ratio to the complex reflection coefficient plane is By the short circuit open circuit load method (short open load method), a short circuit load (T L =1), an open circuit load (T L =-1), a matching load (T L =0) are connected respectively, and ω Lshort , ω Lopen , ω Lmatch Measured under the three conditions, the values of a, b, c and d can be solved.

[0128] The bilinear transformation maps the standing wave ratio to the complex reflection coefficient plane, realizes the conversion from scalar measurement to complex parameter, and fully characterizes the amplitude and phase characteristics of the load impedance. The calculation method of the complex reflection coefficient circle radius directly solves the reflection coefficient by using the geometric relationship, avoids complex algebraic operation, and improves the calculation efficiency. This method maintains good linearity and resolution in a wide impedance range, can quickly respond to load changes, and meets the real-time monitoring requirements.

[0129] Substitute the measured ω L Into the bilinear transformation equation to get the load reflection coefficient T L . The load impedance . Among them, Z0 is the characteristic impedance, and the resistance and reactance components of Z L Are solved by the real part and the imaginary part of T L .

[0130] By collecting voltage ratios and combining them with the linear characteristics of the output matching network (OMN), RF impedance detection is converted into a mathematical model for solution, enabling non-invasive measurement of load impedance. The establishment and solution of the complex plane circle equation utilizes geometric methods to intuitively present impedance characteristics, avoiding direct measurement of complex physical quantities and reducing detection difficulty. The application of the short open-load method further calibrates system errors and improves measurement accuracy, making this method suitable for impedance monitoring and adaptive matching control of various RF power amplifiers.

[0131] Based on the above embodiment, as another optional embodiment, the embodiment of the present application may also include a computer storage medium, which may store multiple instructions, and the instructions are suitable for being loaded by a processor and executing a detection method of the above embodiment. The specific execution process can be found in the specific description of the above embodiment, which will not be repeated here.

[0132] Based on the above embodiment, as another optional embodiment, the embodiment of the present application may further include an electronic device. The electronic device may include: at least one processor, at least one communication bus, a user interface, at least one network interface, and a memory.

[0133] The communication bus is used to realize the connection and communication between these components.

[0134] The user interface may include a display screen (Display) and a camera (Camera). Optional user interfaces may also include a standard wired interface and a wireless interface.

[0135] The network interface may include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0136] The processor may include one or more processing cores. The processor utilizes various interfaces and circuits to connect various components within the server. It executes instructions, programs, code sets, or instruction sets stored in memory, and accesses data stored in memory to perform various server functions and process data. Optionally, the processor may be implemented using at least one of the following hardware forms: a digital signal processing (DSP), a field-programmable gate array (FPGA), or a programmable logic array (PLA). The processor may integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. The CPU primarily processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing content displayed on the display; and the modem handles wireless communications. It is understood that the modem may also be implemented as a separate chip, rather than integrated into the processor.

[0137] The memory may include random access memory (RAM) or read-only memory (ROM). Optionally, the memory may include non-transitory computer-readable storage medium. The memory may be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, sound playback function, image playback function, etc.), instructions for implementing each of the above-mentioned method embodiments, etc.; the data storage area may store data related to each of the above-mentioned method embodiments, etc. The memory may also optionally be at least one storage device located remotely from the aforementioned processor. The memory, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an application program for a detection method.

[0138] In an electronic device, a user interface is mainly used to provide an input interface for the user and obtain data input by the user; and a processor can be used to call an application program storing a detection method in a memory, and when executed by one or more processors, the electronic device executes one or more methods such as those in the above embodiments. It should be noted that for the aforementioned method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the described order of actions, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required for this application.

[0139] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0140] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely schematic, such as the division of units, which is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interface, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0141] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0142] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0143] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of this application, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of this application. The aforementioned memory includes various media that can store program code, such as USB flash drives, mobile hard drives, magnetic disks, or optical disks.

[0144] The above are merely exemplary embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. In other words, any equivalent variations and modifications made in accordance with the teachings of the present disclosure are still within the scope of the present disclosure. Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the disclosure and the practical implications thereof.

[0145] This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not described herein. The description and examples are to be considered as exemplary only, and the scope and spirit of the present disclosure are to be defined by the claims.

Claims

1. A radio frequency power amplifier with a load impedance detection function, characterized in that: include: an input matching network IMN, wherein an input end of the input matching network IMN is connected to a radio frequency input signal RF; A radio frequency power transistor PA, wherein an input end of the radio frequency power transistor PA is connected to an output end of the input matching network IMN; an output matching network OMN, wherein an input end of the output matching network OMN is connected to an output end of the radio frequency power tube PA, an output end of the output matching network OMN is connected to a load, and the output matching network OMN includes a first sampler group S1, a second sampler group S2, and a third sampler group S3; The first sampler group S1 is connected to the main transmission line of the output matching network OMN and is connected between the RF power transistor PA and the DC bias circuit of the output matching network OMN. The DC bias circuit is connected to a power supply and grounded via a capacitor. The first sampler group S1 detects a standing wave in a first section of the main transmission line. The second sampler group S2 is connected to the main transmission line and is connected between the DC bias circuit and the load, and the second sampler group S2 detects the mixed standing wave in the middle section of the main transmission line; The third sampler group S3 is connected to the short circuit line of the output matching network OMN, and the third sampler group S3 detects the pure standing wave on the short circuit line; The first sampler group S1, the second sampler group S2, and the third sampler group S3 include multiple samplers, each of which includes a diode detector D, a coupling capacitor C coup , coupling resistor R coup , filter capacitor C1, filter capacitor C2, isolation resistor R ISO And DC resistance R DC .

2. The radio frequency power amplifier with load impedance detection function according to claim 1, wherein: The signal input terminal of the sampler is connected to the coupling capacitor C coup The first end of the coupling capacitor C coup The second end is connected to the coupling resistor R coup The first end of the coupling resistor R coup The second end of the isolation resistor R ISO The first end of the connection; The first end of the filter capacitor C1 is connected to the coupling resistor R coup The second end of the filter capacitor C1 is grounded; The cathode of the diode detector D is connected to the isolation resistor R ISO The first end of the diode detector D is connected to the ground; The first end of the filter capacitor C2 is connected to the isolation resistor R ISO The second end of the filter capacitor C2 is grounded; The DC resistance R DC The first end is connected to the isolation resistor R ISO Between the second end and the signal output end of the sampler, the DC resistor R DC The second end is grounded.

3. The radio frequency power amplifier with load impedance detection function according to claim 1, wherein: The output matching network OMN is in a linear relationship, and the standing waves corresponding to the samplers, as well as the standing waves and the voltage reflected waves and incident waves of the load are all in a linear relationship.

4. The radio frequency power amplifier with load impedance detection function according to claim 1, wherein: In the output matching network OMN, the electrical length of the line segment set at one end of the RF power tube PA is Φ1, the electrical length of the line segment set at one end of the load is Φ2, the electrical length of the line segment corresponding to the first sampler group S1 is θ1, the electrical length of the line segment corresponding to the second sampler group S2 is θ2, and the electrical length of the line segment corresponding to the third sampler group S3 is θ3.

5. The radio frequency power amplifier with load impedance detection function according to claim 1, wherein: The output matching network OMN includes a first branch and a second branch. The inductive reactance of the first branch is B1, and the inductive reactance of the second branch is B2.

6. A detection method, applied to the radio frequency power amplifier with load impedance detection function according to any one of claims 1 to 5, characterized in that: include: Collect the DC voltage output by each sampler and calculate the voltage ratio; Based on the linear characteristics of the output matching network OMN and in combination with the voltage ratio, a complex plane circle equation is established; Based on the complex plane circle equation, find the intersection points of each circle and determine the standing wave ratio; The standing wave ratio is mapped to the complex reflection coefficient plane, and the load reflection coefficient and impedance are calculated.

7. The detection method according to claim 6, characterized in that The establishment of the complex plane circle equation comprises: collecting the sampled voltages under the loads, and fitting an ellipse on the complex reflection coefficient plane; Parameters of the complex plane circle equation are calculated based on the ellipse coefficients.

8. The detection method according to claim 6, characterized in that The calculating of the load reflection coefficient includes: determining a bilinear transformation of the standing wave ratio to a complex reflection coefficient plane by a short-circuit open-circuit load method.

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