Microwave power detection system and multi-channel microwave power detection consistency control method

Abstract

The present invention discloses a microwave power detection system and a multi-channel microwave power detection consistency control method, which determines the π decay initial values ​​of multiple branch detection modules by performing π decay tests on multiple resistance value combinations through a π decay test circuit unit in the microwave power detection system, and performs multi-channel microwave power detection according to the π decay initial values, and then selects the branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit, and adjusts other branch detection modules based on this to complete the consistency setting of multi-channel microwave power detection. The present invention can effectively eliminate the differences between the branches in the multi-channel microwave power detection process, can better control the consistency of multi-channel microwave power detection, and improve the accuracy and reliability of multi-channel microwave power detection.

Description

Technical Field

[0001] The invention relates to the technical field of microwave power detection, and in particular to a microwave power detection system and a multi-channel microwave power detection consistency control method. Background Art

[0002] With the continuous development of science and technology, the requirements for microwave power detection are increasing, especially in complex systems that require multi-channel high-power microwave power detection.

[0003] On the one hand, high-power microwave systems need to test dozens or even hundreds of microwave signals. Since high-precision testers are only suitable for a very small number of channel test experiments, it is impossible to use high-precision testers to collect dozens or even hundreds of microwave signals. However, traditional microwave power detection systems have great limitations in detection accuracy, especially in high-power microwave systems in high-energy physics and industrial applications, which are difficult to meet high-precision detection requirements. On the other hand, in high-power microwave systems, microwave heating of several kilowatts or even several megawatts must involve dozens of microwave sources for joint heating. The microwave source input power, transmission loss power, and reflected power often require dozens or even hundreds of microwave detection devices. The actual output microwave power is the same, but the difference caused by the internal inconsistency of the microwave detection device will increase the workload of subsequent feedback control. Summary of the invention

[0004] The purpose to be achieved by the present invention is to provide a microwave power detection system and a multi-channel microwave power detection consistency control method to improve the detection accuracy and consistency of multi-channel microwave power detection.

[0005] To achieve the above objectives, an embodiment of the present invention provides a microwave power detection system, including a microwave signal input unit, a power detection unit, a π-decay test circuit unit, and a signal processing and control unit;

[0006] The microwave signal input unit is used to receive a microwave signal and input the microwave signal into the power detection unit;

[0007] The power detection unit includes a plurality of branch detection modules, each of which includes a π decay circuit, a detection circuit and an exponential detector; the π decay circuit is used to process the input microwave signal, the detection circuit is used to receive the microwave signal processed by the π decay circuit, and the exponential detector is used to process the microwave signal processed by the detection circuit into an electrical signal, and output the electrical signal to the signal processing and control unit;

[0008] The signal processing and control unit is used to process and analyze the electrical signal output by the exponential detector to achieve consistency control during multi-channel microwave power detection;

[0009] The π-decay test circuit unit is used to test the π-decay circuit to determine the actual attenuation value and resistance selection value of the π-decay circuit.

[0010] In an optional embodiment, the π-decay test circuit unit includes a test circuit board, and the test circuit board includes a π-decay circuit to be tested, a microstrip impedance matching structure, a fixing device and a test instrument interface;

[0011] The input and output microstrip impedance of the microstrip impedance matching structure is 50 ohms;

[0012] The fixing device is used to fix the two ends of the test circuit board to the copper block through microwave high-frequency connectors;

[0013] The test instrument interface is used to connect to a vector network analyzer so as to test the π-attenuation circuit through the vector network analyzer.

[0014] In an optional embodiment, the exponential detector uses an exponential detector similar to the ADL5501 detector.

[0015] In an optional embodiment, each branch detection module is provided with a voltage stabilizing circuit, and the voltage stabilizing circuit includes a plurality of multi-working voltage detection chips;

[0016] Wherein, each of the multi-operating voltage detection chips is designed and mounted using the same batch of chips.

[0017] In an optional embodiment, the microwave power detection system is powered by a linear power supply.

[0018] In an optional embodiment, the package of the π-decay circuit to be tested includes one of 0603, 0402, 0805 and 1206.

[0019] To achieve the above objectives, an embodiment of the present invention further provides a multi-channel microwave power detection consistency control method, which is applied to the microwave power detection system as described in any one of the above items, comprising:

[0020] Determine the π attenuation range based on test requirements and the linear region of the detector chip;

[0021] Select multiple resistance value combinations according to the π attenuation value range, perform π attenuation tests on the multiple resistance value combinations through the π attenuation test circuit unit, and determine the π attenuation initial values ​​of multiple branch detection modules;

[0022] Perform multi-channel microwave power detection according to the π attenuation initial value to obtain multi-channel microwave power test data, and select a branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit;

[0023] Based on the reference circuit, the π attenuation value in each branch detection module is changed to adjust multiple branch detection modules except the reference circuit to control the consistency of multi-channel microwave power detection.

[0024] In an optional embodiment, the step of selecting a plurality of resistance value combinations according to the π attenuation value range, performing a π attenuation test on the plurality of resistance value combinations through the π attenuation test circuit unit, and determining the π attenuation initial values ​​of the plurality of branch detection modules includes:

[0025] Calculating two types of corresponding π-attenuation resistance values ​​according to the π-attenuation value range, selecting at least two resistance values ​​close to the π-attenuation resistance value for each type of the π-attenuation resistance value, and combining the selected resistance values ​​in pairs to obtain multiple resistance value combinations;

[0026] The π-attenuation test circuit unit performs a π-attenuation test on the plurality of resistance value combinations to obtain actual attenuation values ​​of the plurality of resistance value combinations, and uses the middle value of the actual attenuation value as the π-attenuation initial value of the plurality of branch detection modules.

[0027] In an optional embodiment, the multi-channel microwave power detection is performed according to the π attenuation initial value to obtain multi-channel microwave power test data, and the branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data is selected as the reference circuit, including:

[0028] Using the same signal source, within the power output range of the signal source, with a step length of 1 dBm, test the output voltage data of each detection module to obtain multiple groups of test data corresponding to each detection channel;

[0029] Fitting multiple groups of test data corresponding to each detection channel to obtain a measured output voltage curve of each detection channel;

[0030] The average value curve of the measured output voltage curve of each detection path is calculated, and the detection path of the branch whose measured output voltage curve is closest to the average value curve is selected as the reference circuit.

[0031] In an optional embodiment, after changing the π attenuation value in each branch detection module based on the reference circuit to adjust multiple branch detection modules other than the reference circuit to control the consistency of multi-channel microwave power detection, the method further includes:

[0032] Recheck and test the detection modules of multiple branches to ensure that the acquisition of multiple microwave powers corresponds to the same input and output formula.

[0033] Compared with the prior art, the microwave power detection system and the multi-channel microwave power detection consistency control method provided in the embodiment of the present invention can process the input microwave signal through the π decay circuit, and can adjust the power of the microwave signal to a suitable range, so as to ensure that the subsequent detection circuit and the exponential detector can work normally, thereby improving the accuracy and stability of the detection. In addition, the π decay circuit is tested through the π decay test circuit unit to determine its actual attenuation value and the resistance selection value, thereby further improving the accuracy and consistency of the multi-channel microwave power detection. The multi-channel microwave power detection consistency control method determines the π decay initial values ​​of multiple branch detection modules by performing π decay tests on multiple resistance value combinations through a π decay test circuit unit, which can provide accurate basic data for subsequent power detection and reduce the detection error caused by inaccurate π decay values; and selects the branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit, and adjusts other branch detection modules based on this, which can effectively eliminate the differences between the branches, better control the consistency of multi-channel microwave power detection, make the detection results of each channel closer to the true value, and further improve the accuracy and reliability of multi-channel microwave power detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the present invention, the drawings used in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 is a structural block diagram of a microwave power detection system provided by an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a conventional π decay circuit provided by an embodiment of the present invention;

[0037] Figure 3 The present invention provides a flowchart of a method for controlling the consistency of multi-channel microwave power detection. DETAILED DESCRIPTION

[0038] 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.

[0039] It should be noted that when an element is referred to as being "connected to" another element, it can be directly connected to another element or indirectly connected to the other element. It is understandable that the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the connected circuits, modules, units, etc. have the transmission of electrical signals or data to each other. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. "At least one" means one or more, and "multiple" means two or more.

[0040] The simplest microwave power detection is composed of a detector diode and an auxiliary circuit. However, with the development of semiconductor technology, the detector diode and the auxiliary circuit are integrated into a detector chip, which can more conveniently realize the detection function. At the same time, there are also many ready-made power acquisition devices, which can directly read the power value through certain software, which greatly facilitates microwave power detection. Microwave power test accuracy is the core indicator of microwave detection devices. For simple microwave heating experiments and industrial microwave drying and freezing, the microwave power accuracy does not need to be too high, and it is enough to meet basic needs. However, for some high-energy physics and microwave coating applications that require precision control changes at the W level, higher accuracy is required. For example, in the process of preparing diamonds by microwave plasma method, the range of change cannot exceed 10W when the microwave power is constant, and the quality of diamond coating will be greatly affected. For microwave systems of tens of kilowatts, the change of no more than 10W gives strict requirements for the stability of the microwave source, and also poses a high challenge to the power detection system.

[0041] There are some high-precision microwave power testers, such as Agilent's U2000 series, which have high measurement accuracy and fully meet the accuracy requirements. However, this type of tester is expensive and bulky. It is no problem to test one or two in the laboratory, but it is undoubtedly costly and bulky for high-power microwave systems involving multiple or even dozens of microwave sources. This high-precision microwave power tester is only suitable for power testing of a few channels. For multiple microwave sources, such as the 10MW microwave heating system in the artificial solar nuclear fusion EAST device, it also includes hundreds of kilowatts of solid-state microwave sources that require dozens of microwave synthesis. These high-power microwave systems need to test dozens or even hundreds of microwave signals. Commercial high-precision testers are obviously not suitable for collecting these numbers of microwave signals. Commercial high-precision testers are only suitable for use in very few channel test experiments. They are obviously not suitable for high-power microwave systems in these high-energy physics and industrial applications.

[0042] In the existing high-power microwave system, due to the large number of microwave sources, the power needs to be detected at each level of the power amplifier at the same time, which often requires dozens or even hundreds of power detections. At present, the basic method is online detection, which is to reflect the incident power through microstrip coupling. The basic coupling circuit can be designed by professional simulation software in the early stage, so that the effective accuracy can be guaranteed when detecting low power (generally <10W). However, when designing online detection for tens of watts or hundreds of watts, the results of professional simulation software designing high-power microwave circuits can only provide a general direction, and the simulation value will be very different from the theoretical value, such as after actual adjustment. In the high-power microwave state, the accuracy of online detection is affected by many factors such as cavity material, cavity height, shielding cavity size, etc., and the accuracy is difficult to guarantee. In addition, in high-power microwave systems, microwave heating of several kilowatts or even several megawatts must involve dozens of microwave sources for joint heating. The input power of the microwave source, the power loss during the transmission process, and the reflected power often require dozens or even hundreds of microwave detection devices. The actual output microwave power is the same, but the difference caused by the internal inconsistency of the microwave detection device will increase the workload of subsequent feedback control. Therefore, how to improve the consistency of power detection in high-power microwave systems is also a prominent issue.

[0043] Based on the above-mentioned problems existing in the prior art, the embodiments of the present invention, in combination with the accompanying drawings, propose a microwave power detection system and a multi-channel microwave power detection consistency control method, which will be described in detail below.

[0044] See also Figure 1 , Figure 1 is a structural block diagram of a microwave power detection system provided by an embodiment of the present invention. Figure 1 As shown, the microwave power detection system includes a microwave signal input unit 1, a power detection unit 2, a π decay test circuit unit 3, and a signal processing and control unit 4;

[0045] The microwave signal input unit 1 is used to receive a microwave signal and input the microwave signal to the power detection unit 2;

[0046] The power detection unit 2 includes a plurality of branch detection modules 21-2n, each branch detection module 2n includes a π decay circuit 21n, a detection circuit 22n and an exponential detector 23n; the π decay circuit is used to process the input microwave signal, the detection circuit is used to receive the microwave signal processed by the π decay circuit, and the exponential detector is used to process the microwave signal processed by the detection circuit into an electrical signal, and output the electrical signal to the signal processing and control unit;

[0047] The signal processing and control unit 4 is used to process and analyze the electrical signal output by the exponential detector to achieve consistency control during multi-channel microwave power detection;

[0048] The π-decay test circuit unit 3 is used to test the π-decay circuit to determine the actual attenuation value and resistance selection value of the π-decay circuit.

[0049] Exemplarily, the system consists of a microwave signal input unit, a power detection unit, a π-decay test circuit unit, and a signal processing and control unit. The microwave signal input unit is connected to an external microwave source to introduce the microwave signal into the system; the power detection unit includes N branch detection modules, which are responsible for power detection of microwave signals; the π-decay test circuit unit is used to accurately measure the parameters of the π-decay circuit before performing multi-channel microwave power testing; the signal processing and control unit analyzes and processes the detection data to achieve consistency control of multi-channel detection.

[0050] It should be noted that in traditional microwave power detection systems, the commonly used detector is a logarithmic detector.

[0051] However, the power difference corresponding to the change in the detection voltage of the logarithmic detector is large, resulting in an unstable detection voltage output. During the microwave power detection process, this large power difference change will cause the output voltage to fluctuate significantly. At the same time, the logarithmic detector response value does not conform to the forward logic, which is not conducive to the operator's intuitive understanding and analysis of the detection results during actual operation and data processing.

[0052] In this regard, in order to increase the smoothness of power detection, the embodiment of the present invention no longer uses a logarithmic detector such as AD8139, but uses an exponential detector instead of a logarithmic detector. Because the power difference corresponding to the detection voltage change of the exponential detector is much smaller, the output detection voltage is more stable, which is extremely beneficial to subsequent control work and can significantly reduce the workload of consistency control. At the same time, in comparison, the response value of the exponential detector is more in line with the forward logic, which is convenient for operators to quickly understand the power changes represented by the detection data, and has more advantages in data processing and system control.

[0053] In an optional embodiment, the exponential detector uses an exponential detector similar to the ADL5501 detector.

[0054] It should be noted that the ADL5501 is a mean-response power detector, which is suitable for measuring high crest factor signals, with an operating frequency range of 50MHz to 6GHz and excellent temperature stability within 30dB. Therefore, the use of similar exponential detectors can also accurately measure power when facing these complex modern communication waveforms, cover a wider frequency range, maintain relatively stable performance under different ambient temperatures, ensure the accuracy and reliability of the measurement results, and reduce the impact of temperature on system performance.

[0055] It should be noted that, in general, the required resistance composition of the π decay circuit is calculated by the required attenuation value. Figure 2 As shown in the figure, the conventional π attenuation circuit is composed of three resistors, namely R1, R2 and R3. Among them, R2 and R3 are connected between the input and output terminals and the ground respectively, and R1 is connected between the input and output terminals, forming a π-shaped circuit structure. Based on the principle of resistor voltage division, when the signal passes through the π-type attenuation circuit, the input signal first passes through a series resistor R2, which will have a certain voltage division effect on the signal, reducing the signal voltage. Then the signal passes through the parallel resistor R1, and part of the signal is shunted to the ground, further reducing the amplitude of the output signal. Finally, the signal passes through a series resistor R3 and is divided again, thereby achieving the attenuation of the signal amplitude. By reasonably selecting the resistance values ​​of the three resistors, the precise control of the signal attenuation can be achieved.

[0056] For example, if the attenuation value needs to be 11dB, according to calculation, the recommended value is series resistance R1=81.66; two ground resistances R2=R3=89.24 to form a π attenuation circuit to achieve an attenuation value of 11dB. However, in reality, such resistance values ​​basically do not exist, or there are only resistors with a resistance value accuracy of approximately 0.1% but are expensive. In general, the actual attenuation of the π attenuation resistor is 0.1-0.3dB different from the calculated value. For low power of tens of watts, these differences do not matter, but for high-power microwave system measurements of several kilowatts and megawatts, this difference is unacceptable. Therefore, in order to improve the detection accuracy, the actual attenuation value of the π attenuation circuit must be clearly defined, and the signal cannot be adjusted according to the default attenuation value.

[0057] Meanwhile, conventional π decay measurements are all online measurements, that is, in real-time measurements, the π decay circuit is mainly measured through probes or leads, but the measurement results may vary due to the firmness of the angle welding of the probes or leads.

[0058] Therefore, in view of the above problems in the prior art, in order to accurately test the actual attenuation value of the π-decay circuit, the embodiment of the present invention specially makes a π-decay test circuit unit for the π-decay circuit.

[0059] In an optional embodiment, the π-decay test circuit unit includes a test circuit board, and the test circuit board includes a π-decay circuit to be tested, a microstrip impedance matching structure, a fixing device and a test instrument interface;

[0060] The input and output microstrip impedance of the microstrip impedance matching structure is 50 ohms;

[0061] The fixing device is used to fix the two ends of the test circuit board to the copper block through microwave high-frequency connectors;

[0062] The test instrument interface is used to connect to a vector network analyzer so as to test the π-attenuation circuit through the vector network analyzer.

[0063] It can be understood that the intermediate circuit of the test circuit is the π-attenuation circuit to be tested. According to the test circuit board design, the input and output microstrip impedance is a standard 50 ohms, and the test circuit board is fixed on a copper block, and its two ends are fixed with microwave high-frequency connectors SMA connectors, and then the π-attenuation test is performed on the π-attenuation circuit to be tested by connecting to a vector network analyzer.

[0064] When performing multi-channel microwave power detection, appropriate resistor combinations can be selected in advance according to the required attenuation value, and then the actual attenuation values ​​of these resistor combinations can be tested through the π attenuation test circuit unit, and then the resistor combination corresponding to the middle value of the attenuation value is selected and uniformly welded to form a π attenuation circuit in the N branch detection modules. Compared with conventional online measurements, the results of multi-channel microwave power tests are the most accurate, and the attenuation value of the π attenuation circuit will not be affected by differences in probe or lead welding lengths.

[0065] Specifically, the package of the π decay circuit to be tested can be 0603, but is not limited to 0603, and can also be 0402 / 0805 / 1206, etc. Specifically, the 0402 package is a smaller package type, which occupies a small space, and the 0603 package size is moderate, taking into account a certain power carrying capacity and space occupancy. Compared with the 0402 package, it can withstand higher power, has better current carrying capacity and heat dissipation performance, and does not occupy too much space on the circuit board. The 0805 package is relatively large in size, can provide higher power handling capacity and greater current carrying capacity, and has better heat dissipation performance. In terms of high-frequency characteristics, compared with smaller packages, it can reduce the influence of parasitic effects to a certain extent. 1206 is one of the larger packages among these packages, has strong power carrying capacity and current handling capacity, can withstand large power loss, and has good heat dissipation performance. In specific implementation, a suitable package form can be selected according to power requirements.

[0066] In an optional embodiment, each of the detection modules is provided with a voltage stabilizing circuit, and the voltage stabilizing circuit includes a plurality of multi-working voltage detection chips;

[0067] Wherein, each of the multi-operating voltage detection chips is designed and mounted using the same batch of chips.

[0068] In an optional embodiment, the microwave power detection system is powered by a linear power supply.

[0069] It is worth noting that the inventors found in actual tests that the power supply ripple has a great influence on the detection output voltage. Therefore, when performing multi-channel microwave power detection, it is recommended to use a unified power supply and a linear power supply with a small ripple, so as to avoid the interference noise introduced by the switching power supply as much as possible. At the same time, in the microwave power detection system, in order to further avoid the detection output fluctuation caused by power supply noise, a voltage stabilizing circuit can be used again inside each branch detection module, so that the detection output fluctuation can be reduced to a minimum, thereby further improving the measurement accuracy and detection consistency.

[0070] On the basis of the above system item embodiment, in order to further improve the accuracy of multi-channel microwave power detection and the consistency of multi-channel microwave power detection, the embodiment of the present invention provides a multi-channel microwave power detection consistency control method.

[0071] See also Figure 3 , Figure 3 FIG. 1 is a flow chart of a multi-channel microwave power detection consistency control method provided by an embodiment of the present invention. Figure 3 As shown, the multi-channel microwave power detection consistency control method includes steps S1 to S4:

[0072] S1. Determine the π attenuation range according to the test requirements and the linear region of the detector chip;

[0073] Understandably, the π attenuation value range needs to be determined first, which can be determined based on the system test requirements and the linear region of the detector chip. For example, if it is necessary to simultaneously collect multiple 1kW (60dBm, i.e. 60 decibel milliwatt) powers, the coupler coupling is 40dB, and the selected detector chip ADL5501 has an input range of about -25dBm to 10dBm that is basically linear with the output voltage.

[0074] For a 1kW amplifier, we hope to detect a power of 0-1kW during testing, but the actual output may be larger, so the detection range should be able to collect a maximum of about 1.25kW (61dBm), and the detection range can be determined to be between 0dBm (1mW)-61dBm. For an input power of 0dBm (1mW) -61dBm, after 40dB coupling, the coupled power is between -40dBm and 21dBm. For high-power measurement, an accuracy of 20dBm (0.1W) is actually very high in industry, so we need to focus on the range of -20dBm-21dBm. Then, based on the linear range of the selected chip being -25dBm-10dBm (that is, the goal is to attenuate the signal from -20dBm to 21dBm through the π attenuation circuit to the linear range of the detection chip -25dBm to 10dBm), considering the most extreme case, the 21dBm signal needs to be attenuated to about 10dBm, so the attenuation required is 21-10=11dB (the difference between 21dBm and 10dBm represents the relative change in power, so it is expressed in dB). Then, we can basically determine that the value of π attenuation is around 11dB.

[0075] S2, selecting a plurality of resistance value combinations according to the π attenuation value range, performing a π attenuation test on the plurality of resistance value combinations through the π attenuation test circuit unit, and determining the π attenuation initial values ​​of the plurality of branch detection modules;

[0076] In an optional embodiment, the step of selecting a plurality of resistance value combinations according to the π attenuation value range, performing a π attenuation test on the plurality of resistance value combinations through the π attenuation test circuit unit, and determining the π attenuation initial values ​​of the plurality of branch detection modules includes:

[0077] Calculating two types of corresponding π-attenuation resistance values ​​according to the π-attenuation value range, selecting at least two resistance values ​​close to the π-attenuation resistance value for each type of the π-attenuation resistance value, and combining the selected resistance values ​​in pairs to obtain multiple resistance value combinations;

[0078] The π-attenuation test circuit unit performs a π-attenuation test on the plurality of resistance value combinations to obtain actual attenuation values ​​of the plurality of resistance value combinations, and uses the middle value of the actual attenuation value as the π-attenuation initial value of the plurality of branch detection modules.

[0079] It can be understood that most of the π decay resistors are non-integer values, and some non-integer values ​​of π decay are rare in the market, or the price is extremely high. For these unconventional values, the embodiments of the present invention try to select similar non-integer resistors. Taking the determination of the π decay value of 11dB as an example, it is generally recommended that two numerical resistors of 89.24 and 81.66 are required, but in practice such resistance values ​​basically do not exist. However, in practice, integer resistance values ​​of 91 or 82 are very common and suitable for batch processing, but through testing on the π decay test circuit unit of the embodiment of the present invention, the actual attenuation value of this resistor combination is only 10.73. Therefore, the embodiment of the present invention continues to try to select similar resistors in stock on the market for fine-tuning. For example, the resistance values ​​near 81.66 and 89.24 are very common except for 82 and 91, and others such as 86.6 and 88.7 are also relatively easy to obtain on the market, and are cheaper and have a shorter delivery time than other resistance values.

[0080] Therefore, the embodiment of the present invention selects 4 resistors with resistance values ​​of 82, 86.6, 88.7 and 91. After the 4 resistors are combined in pairs, there are 16 combinations. Through the π decay test circuit of the embodiment of the present invention, the attenuation values ​​of the 16 combinations are measured by a vector network analyzer, and the characteristic impedance is measured. See Table 1, which shows the actual attenuation value and impedance corresponding to the π decay circuit after each resistor combination provided by the embodiment of the present invention.

[0081] Table 1 Actual attenuation value and impedance of the π decay circuit corresponding to each resistance combination

[0082]

[0083] It can be seen from Table 1 that among the test values ​​of 16 resistance combinations, the measured π decay median value is 11.18, and the corresponding three π decay resistors are all 82 ohms. Therefore, in the embodiment of the present invention, these three resistors with a resistance value of 82 ohms form a π decay circuit in each branch detection circuit, and 11.18dB is used as the π decay initial value of each branch. Initially, these multiple paths (N paths) use the same π decay initial value.

[0084] It is worth noting that the impedance corresponding to the classic value of π decay is 50 ohms, and the actual value of the resistor is definitely different from the theoretical value. From the measured values ​​in Table 1, it can be seen that the impedance is greater than 50 ohms, with a maximum of 60.9 ohms; the minimum attenuation is 10.73dB and the maximum is 11.67dB. Because in practical applications such as multi-channel microwave power detection, multiple π decay circuits are required to process signals from different channels, and these π decay circuits have different impedances and attenuations due to differences in resistor selection. Through the actual data obtained from this test, these π decay circuits can be adjusted in subsequent work in combination with the test data in Table 1 to make their performance (such as impedance matching and attenuation) more consistent. For example, by fine-tuning the resistance value or adopting other compensation measures, multiple π decay circuits can achieve similar performance in practical applications, thereby improving the consistency and accuracy of the entire multi-channel microwave power detection system. Therefore, these test data are also prepared for the subsequent consistency adjustment of multi-channel microwave power detection.

[0085] It is worth noting that the π-attenuation test method adopted in the embodiment of the present invention is not only applicable to the consistency adjustment of multi-channel microwave power detection in the embodiment of the present invention, but can also be applied to π-attenuation circuits in other microwave circuits as isolation, pre-stage attenuation and other applications.

[0086] S3, performing multi-channel microwave power detection according to the π attenuation initial value to obtain multi-channel microwave power test data, and selecting a branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit;

[0087] In an optional embodiment, the multi-channel microwave power detection is performed according to the π attenuation initial value to obtain multi-channel microwave power test data, and the branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data is selected as the reference circuit, including:

[0088] Using the same signal source, within the power output range of the signal source, with a step length of 1 dBm, test the output voltage data of each detection module to obtain multiple groups of test data corresponding to each detection channel;

[0089] Fitting multiple groups of test data corresponding to each detection channel to obtain a measured output voltage curve of each detection channel;

[0090] The average value curve of the measured output voltage curve of each detection path is calculated, and the detection path of the branch whose measured output voltage curve is closest to the average value curve is selected as the reference circuit.

[0091] For example, N-channel detection is tested, and the same signal source is used as the test source. The test range is -20dBm (the lowest value of the signal source used) to 25dBm (the highest value of the signal source used), and the step is 1dBm. The output voltage data of the N-channel detection module is tested and recorded, and the N-channel input and output data are fitted. Since the power supply of the detection chip is provided by the internal voltage regulator circuit of the module, the internal voltage regulator circuit theoretically outputs 3.3V, and the test results show that it varies from 3.1 to 3.35V. At the same time, the accuracy of the π decay resistor affects the output curve, which is understandable. The highest value and the lowest value of the N-channel test data can be removed, and the average value can be removed. The data of the N-channel test data that is closest to the average value is selected as the benchmark. In practice, each detection module tests a total of 45 data from -20 to 25, and a total of N*45 groups of data are measured. After removing the two maximum values ​​at each power level, the average value is taken, and the branch closest to the average value curve in the measured curve is selected as the benchmark circuit.

[0092] S4. Based on the reference circuit, the π attenuation value in each branch detection module is changed to adjust multiple branch detection modules except the reference circuit to control the consistency of multi-channel microwave power detection.

[0093] In an optional embodiment, after the step of changing the π attenuation value in each branch detection module based on the reference circuit to adjust multiple branch detection modules other than the reference circuit to control the consistency of multi-channel microwave power detection, the method further includes:

[0094] Recheck and test the detection modules of multiple branches to ensure that the acquisition of multiple microwave powers corresponds to the same input and output formula.

[0095] Specifically, based on the reference circuit, the other N-1 channels except the reference circuit are adjusted respectively. The adjustment is mainly completed by changing the π attenuation, which is also the reason why the π attenuation selection value is initially set to the middle value, so as to facilitate subsequent fine-tuning. In addition, each channel after adjustment should be measured to record whether the curve is consistent with the reference curve. Finally, after the N channels are adjusted, the N channels are re-checked and tested, the detection results between the channels are compared, the consistency of the entire multi-channel microwave power detection system is analyzed, and the consistency setting is completed. After completing the consistency setting, the N-channel acquisition channels can be described by the same input and output formula. That is, no matter which channel, given the same input microwave power signal, the corresponding output detection result can be calculated by this unified formula. The advantage of this is that when designing the system and processing data, there is no need to establish complex and different mathematical models and calculation methods for each channel separately, which greatly simplifies the theoretical architecture and actual operation process of the system.

[0096] In summary, a microwave power detection system and a multi-channel microwave power detection consistency control method provided by an embodiment of the present invention, the microwave power detection system realizes a complete process from microwave signal input to final power detection result output through the orderly cooperation of a microwave signal input unit, a power detection unit, a π decay test circuit unit, and a signal processing and control unit, and each unit has a clear division of labor, ensuring the accuracy and reliability of microwave power detection. Among them, the power detection unit includes multiple branch detection modules, which can detect multiple microwave signals at the same time, meet the needs of power detection of multiple microwave signals in practical applications, and improve the detection efficiency and the practicality of the system. At the same time, the input microwave signal can be processed by the π decay circuit, and the power of the microwave signal can be adjusted to a suitable range, ensuring that the subsequent detection circuit and the exponential detector can work normally, and improving the accuracy and stability of the detection. In addition, the π decay circuit is tested by the π decay test circuit unit to determine its actual attenuation value and resistance selection value, further improving the accuracy and consistency of multi-channel microwave power detection.

[0097] The multi-channel microwave power detection consistency control method first determines the π decay value range according to the test requirements and the linear region of the detection chip, which can ensure that the microwave signal is processed within the linear working region of the detection chip, avoids the signal from being distorted or errored due to exceeding the linear region, and thus improves the accuracy of power detection; performs π decay tests on multiple resistance value combinations through a π decay test circuit unit to determine the π decay initial values ​​of multiple branch detection modules, which can provide accurate basic data for subsequent power detection and reduce the detection error caused by inaccurate π decay values; and selects the branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit, and adjusts other branch detection modules based on this, which can effectively eliminate the differences between the branches, can better control the consistency of the multi-channel microwave power detection, make the detection results of each channel closer to the true value, and further improve the accuracy and reliability of the multi-channel microwave power detection.

[0098] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A multi-channel microwave power detection consistency control method, characterized in that: Applied to a microwave power detection system, the microwave power detection system comprising: Microwave signal input unit, power detection unit, π decay test circuit unit, signal processing and control unit; The microwave signal input unit is used to receive a microwave signal and input the microwave signal into the power detection unit; The power detection unit includes a plurality of branch detection modules, each of which includes a π decay circuit, a detection circuit and an exponential detector; the π decay circuit is used to process the input microwave signal, the detection circuit is used to receive the microwave signal processed by the π decay circuit, and the exponential detector is used to process the microwave signal processed by the detection circuit into an electrical signal, and output the electrical signal to the signal processing and control unit; The signal processing and control unit is used to process and analyze the electrical signal output by the exponential detector to achieve consistency control during multi-channel microwave power detection; The π decay test circuit unit is used to test the π decay circuit to determine the actual attenuation value and resistance selection value of the π decay circuit; The multi-channel microwave power detection consistency control method comprises: Determine the π attenuation range based on test requirements and the linear region of the detector chip; Select multiple resistance value combinations according to the π attenuation value range, perform π attenuation tests on the multiple resistance value combinations through the π attenuation test circuit unit, and determine the π attenuation initial values ​​of multiple branch detection modules; Perform multi-channel microwave power detection according to the π attenuation initial value to obtain multi-channel microwave power test data, and select a branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit; Based on the reference circuit, the π attenuation value in each branch detection module is changed to adjust multiple branch detection modules except the reference circuit to control the consistency of multi-channel microwave power detection.

2. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: The step of selecting a plurality of resistance value combinations according to the π attenuation value range, performing π attenuation tests on the plurality of resistance value combinations through the π attenuation test circuit unit, and determining the π attenuation initial values ​​of the plurality of branch detection modules includes: Calculating two types of corresponding π-attenuation resistance values ​​according to the π-attenuation value range, selecting at least two resistance values ​​close to the π-attenuation resistance value for each type of the π-attenuation resistance value, and combining the selected resistance values ​​in pairs to obtain multiple resistance value combinations; The π-attenuation test circuit unit performs a π-attenuation test on the plurality of resistance value combinations to obtain actual attenuation values ​​of the plurality of resistance value combinations, and uses the middle value of the actual attenuation value as the π-attenuation initial value of the plurality of branch detection modules.

3. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: The method of performing multi-channel microwave power detection according to the π attenuation initial value to obtain multi-channel microwave power test data, and selecting a branch detection module whose microwave power test data is closest to the average value of the multi-channel microwave power test data as a reference circuit, comprises: Using the same signal source, within the power output range of the signal source, with a step length of 1 dBm, test the output voltage data of each detection module to obtain multiple groups of test data corresponding to each detection channel; Fitting multiple groups of test data corresponding to each detection channel to obtain a measured output voltage curve of each detection channel; The average value curve of the measured output voltage curve of each detection path is calculated, and the detection path of the branch whose measured output voltage curve is closest to the average value curve is selected as the reference circuit.

4. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: After changing the π attenuation value in each branch detection module based on the reference circuit to adjust multiple branch detection modules except the reference circuit to control the consistency of multi-channel microwave power detection, the method further includes: Recheck and test the detection modules of multiple branches to ensure that the acquisition of multiple microwave powers corresponds to the same input and output formula.

5. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: The π-decay test circuit unit comprises a test circuit board, and the test circuit board comprises a π-decay circuit to be tested, a microstrip impedance matching structure, a fixing device and a test instrument interface; The input and output microstrip impedance of the microstrip impedance matching structure is 50 ohms; The fixing device is used to fix the two ends of the test circuit board to the copper block through microwave high-frequency connectors; The test instrument interface is used to connect to a vector network analyzer so as to test the π-attenuation circuit through the vector network analyzer.

6. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: The exponential detector operates in a frequency range of 50 MHz to 6 GHz.

7. The multi-channel microwave power detection consistency control method according to claim 1, characterized in that: Each branch detection module is provided with a voltage stabilizing circuit, and the voltage stabilizing circuit includes a plurality of multi-working voltage detection chips; Wherein, each of the multi-operating voltage detection chips is designed and mounted using the same batch of chips.

8. The multi-channel microwave power detection consistency control method according to claim 5, characterized in that: The microwave power detection system is powered by a linear power supply.

9. The multi-channel microwave power detection consistency control method according to claim 5, characterized in that: The package of the π-decay circuit to be tested includes one of 0603, 0402, 0805 and 1206.

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