Method for calibrating effective efficiency correction factor

Abstract

The invention provides a method for calibrating an effective efficiency correction factor, and belongs to the technical field of coaxial microwave power benchmark, and the method comprises the steps: collecting a radio frequency transient thermoelectric force change curve of a power sensor under radio frequency power and a direct current transient thermoelectric force change curve under direct current power through a millivoltmeter; the radio-frequency steady-state temperature rise potential in the radio-frequency transient thermoelectric force change curve is used as a steady-state value, the direct-current transient thermoelectric force change curve is normalized and then used as an initial reference curve, and a compression coefficient is calculated through early-stage data and steady-state values of the radio-frequency transient thermoelectric force change curve and the direct-current transient thermoelectric force change curve; and based on the compression coefficient, compressing the initial reference curve through an iterative algorithm, carrying out convergence to obtain a convergence reference curve, and carrying out calculation according to the convergence reference curve to obtain an effective efficiency correction factor. The problems that a traditional effective efficiency correction factor calibration method is large in uncertainty and not easy to obtain, and the obtaining difficulty is increased along with frequency increase are solved.

Description

Technical Field

[0001] This invention belongs to the field of coaxial microwave power reference technology, and particularly relates to a method for calibration effective efficiency correction factor. Background Technology

[0002] In recent decades, research progress on calibration methods for coaxial microwave power references has lagged behind industrial technological advancements, becoming a key bottleneck restricting the traceability of coaxial microwave / millimeter-wave power. Specifically, the highest operating frequency of currently commercially available coaxial power sensors has reached 110 GHz (1.0 mm connector), but the upper limit of reported coaxial power references is only 50 GHz (2.4 mm connector), while key international comparisons remain at the N-type (18 GHz) level completed in 2000 (CCEM.RF-K8.CL).

[0003] The core issue behind this lag lies in the technical bottleneck in determining the effective efficiency correction factor g. g corrects the impact of thermal insulation transmission line loss on calorimetric results. The methods for obtaining g in waveguide and coaxial references are as follows: waveguide references can achieve signal isolation through short-circuit tests, directly determining the correction factor g; coaxial references, due to the difficulty in achieving ideal short-circuit or open-circuit states online, rely instead on spatial isolation methods such as back-to-back tests and short-circuit / open-circuit tests to measure the impact of the thermal insulation section separately, indirectly determining the correction factor g.

[0004] However, as the frequency increases, the loss of the insulation section increases significantly, making it difficult to meet the mirror conditions required for back-to-back experiments, and the preparation of ideal short-circuit / open-circuit sockets also faces challenges; the technical route of obtaining effective efficiency correction factors by relying on physical isolation methods has encountered an insurmountable bottleneck in the development of millimeter-wave coaxial power references. Summary of the Invention

[0005] To address the aforementioned shortcomings in existing technologies, this invention provides a method for calibrating the effective efficiency correction factor, which solves the problems of large uncertainty, difficulty in obtaining the corrected factor, and increasing difficulty in obtaining the corrected factor as the frequency increases in traditional calibration methods.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a method for calibrating an effective efficiency correction factor, comprising the following steps: Radio frequency power is input to the power sensor under calibration, and the radio frequency transient thermoelectric potential change curve is obtained by a millivoltmeter. The radio frequency steady-state temperature rise potential in the radio frequency transient thermoelectric potential change curve is taken as the steady-state value. DC power is input to the power sensor under test, and the DC transient thermoelectric potential change curve is acquired by a millivoltmeter. The DC transient thermoelectric potential change curve is then normalized to obtain an initial reference curve. Calculate the maximum difference between the early stage of the radio frequency transient temperature rise potential in the radio frequency transient thermoelectric potential change curve and the early stage of the DC transient temperature rise potential in the DC transient thermoelectric potential change curve, and use the ratio of the maximum difference value to the steady-state value as the compression coefficient. Based on the compression coefficient, the initial reference curve is compressed using an iterative algorithm. The thermoelectric potential of the heat insulation section and the thermoelectric potential of the transmission line inside the base of the power sensor are separated from the steady-state value to obtain the convergence reference curve. Based on the convergence reference curve, the transmission line loss within the power sensor is calculated to obtain the effective efficiency correction factor.

[0007] To address the inaccuracy of the effective efficiency correction factor calculated by traditional physical isolation methods in high-frequency scenarios, this invention provides a method for calibrating the effective efficiency correction factor without relying on physical isolation. It uses a calorimeter to collect the transient temperature rise potential of the power sensor under RF power and the transient temperature rise potential of the load acting alone under DC power. Through iterative decoupling and separation of the coupling loss between the insulation section and the transmission line inside the mounting base, and combined with the calculation of the transmission line loss inside the power sensor, it achieves accurate calibration of the effective efficiency correction factor without physical isolation. This overcomes the failure bottleneck of traditional physical isolation methods at high frequencies and improves the traceability accuracy of coaxial microwave and millimeter-wave power references.

[0008] Furthermore, the expression for the convergence reference curve is as follows:

[0009]

[0010] in, For the first The new reference curve for the next iteration As the initial reference curve, This is the steady-state value. For the first The difference in the next iteration. For the first Compression coefficient of the next iteration For the first The thermoelectric potential generated by the insulation section in the next iteration For the first Thermoelectric potential generated by the transmission line within the next iteration seat. This is the radio frequency temperature rise potential curve.

[0011] The convergence criterion for the new reference curve is expressed as follows:

[0012] in, For the first The difference in the next iteration. The convergence reference curve is obtained when the convergence criterion of the new reference curve is satisfied, which is the convergence threshold.

[0013] Furthermore, the expression for the effective efficiency correction factor is as follows:

[0014]

[0015]

[0016] in, As an effective efficiency correction factor, This is the thermal equivalent factor for power loss on the transmission line within the power sensor. This is the thermal equivalent factor for the power loss in the insulation section. This refers to the power loss ratio of the transmission line within the power sensor. The power loss ratio of the heat insulation section of the power sensor. This represents the steady-state value of the RF temperature rise potential curve. To converge the steady-state value of the reference curve, This refers to the power loss on the transmission line within the power sensor. This is the net power loss of the power sensor. This represents the power loss of the insulation section.

[0017] The beneficial effects of this invention are as follows: This invention provides a calibration effective efficiency correction factor method that overcomes the bottleneck of traditional physical isolation methods failing in high-frequency scenarios. It extends the upper limit of coaxial microwave and millimeter-wave power benchmark calibration to higher frequency bands, providing traceability for high-frequency power benchmarks. By collecting thermal information from the temperature rise curve after adding radio frequency power, it uses an iterative algorithm to decouple the heat sources in the calorimeter and determine the effective efficiency correction factor, ultimately determining the effective efficiency of the power sensor being calibrated. This eliminates the need to prepare ideal short-circuit / open-circuit sockets and build complex physical isolation devices; the calibration effective efficiency correction factor can be achieved simply through conventional data acquisition and algorithms, simplifying the calibration process and reducing computational costs. Furthermore, this invention can be used with various coaxial connectors and a wide frequency range, expanding the frequency application scenarios. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for adjusting the effective efficiency factor in calibration. Detailed Implementation

[0019] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0020] Example 1 like Figure 1 The diagram shown is a flowchart of a method for adjusting the calibration effectiveness efficiency factor. This invention provides a method for adjusting the calibration effectiveness efficiency factor, comprising the following steps: Radio frequency power is input to the power sensor under calibration, and the radio frequency transient thermoelectric potential change curve is obtained by a millivoltmeter. The radio frequency steady-state temperature rise potential in the radio frequency transient thermoelectric potential change curve is taken as the steady-state value. DC power is input to the power sensor under test, and the DC transient thermoelectric potential change curve is acquired by a millivoltmeter. The DC transient thermoelectric potential change curve is then normalized to obtain an initial reference curve. Calculate the maximum difference between the early stage of the radio frequency transient temperature rise potential in the radio frequency transient thermoelectric potential change curve and the early stage of the DC transient temperature rise potential in the DC transient thermoelectric potential change curve, and use the ratio of the maximum difference value to the steady-state value as the compression coefficient. Based on the compression coefficient, the initial reference curve is compressed using an iterative algorithm. The thermoelectric potential of the heat insulation section and the thermoelectric potential of the transmission line inside the base of the power sensor are separated from the steady-state value to obtain the convergence reference curve. Based on the convergence reference curve, the transmission line loss within the power sensor is calculated to obtain the effective efficiency correction factor.

[0021] This invention proposes a method to determine the effective efficiency of a power sensor under calibration without relying on physical isolation. This method involves acquiring thermal information from the temperature rise curve after the addition of radio frequency power, using an iterative algorithm to decouple heat sources within a calorimeter, determine a correction factor, and ultimately establish the effective efficiency of the calibrated power sensor. According to the first law of thermodynamics—the law of conservation of energy—when a power sensor absorbs power, the energy is expressed as heat. The microcalorimeter measures the actual power absorbed by the power sensor by measuring the change in heat, directly measuring the uncorrected effective efficiency of the calibrated power sensor. Multiplying this by the correction factor yields the effective efficiency of the calibrated sensor.

[0022] In conventional technical solutions, the purpose of developing a power reference is to determine the effective efficiency of the power sensor being calibrated. Effective efficiency is defined as the sensor's indicated power. With net power The ratio is denoted as Its expression is as follows:

[0023] A sensor whose effective efficiency is determined by a benchmark can be used as a transfer standard to transfer the measurement value of the standard measuring instrument to be tested. The benchmark determines the net power loss of the sensor being calibrated by calorimetry. In order to improve the sensitivity of calorimetry, the sensor being calibrated is connected to the thermal ground through a transmission line in the calorimeter.

[0024] After adding radio frequency power, the temperature rise potential measured by the thermopile includes the contribution of the power loss in the insulation section. Due to the different heat transfer paths, the power absorbed by the power sensor and the power loss in the insulation transmission line have different effects on the temperature rise of the thermopile, as expressed below:

[0025] in, This is the change in electric potential due to temperature rise. The sensitivity of the thermopile to DC power loss from the load. The thermal equivalent factor of the power lost under load. This is the thermal equivalent factor for the power loss on the transmission line within the sensor. The thermal equivalent factor for the power loss in the insulation section. The power lost by the load. This refers to the power loss on the transmission line within the sensor. This refers to the power loss in the insulation section; make Then we can get:

[0026] Meanwhile, the heat generated by the load loss RF power and the DC power has the same heat conduction path, therefore According to the physical definition ,but , bring in expressions and The expression can ultimately be obtained as follows:

[0027] in, This is the uncorrected effective efficiency, which can be obtained directly from calorimetric results. This refers to the effective efficiency correction factor. The purpose of this invention is to reasonably and accurately calibrate the effective efficiency correction factor. .

[0028] In low-frequency systems, the power loss ratio of the transmission line within the power sensor is... The value is very small, generally less than 1%, therefore, in existing technologies such as waveguide systems, the thermal equivalence factor of the power loss on the transmission line within the sensor is very small. We can take 0, and get:

[0029] As technology advances, the frequency of coaxial microwave / millimeter-wave power is also increasing, currently reaching a maximum of 110 GHz. However, at 50 GHz, the loss in the heat-insulating section increases significantly, and the power loss of the transmission line within the power sensor is higher than that of the standard power sensor. The value will gradually increase, and the accuracy of traditional effective efficiency correction factor calibration methods is difficult to guarantee.

[0030] In conventional coaxial microwave and millimeter-wave power references, the thermoelectric potential change curve measured by the thermopile after adding radio frequency power contains important information about the sensor being calibrated. However, previous reference development only focused on the steady-state thermoelectric potential after thermal equilibrium and calculated the uncorrected effective efficiency accordingly, neglecting the important information hidden in the early transient thermal response. This information corresponds to the effective efficiency of the sensor being calibrated. This invention utilizes this important information to reflect the changes in transient thermoelectric potential under radio frequency power and DC power by collecting radio frequency transient thermoelectric potential change curves and DC transient thermoelectric potential change curves. By analyzing the differences in the early data of the two data sets, an iterative algorithm is used to separate the thermal contribution of the power sensor load, thereby decoupling the thermal effects between the insulation section, the transmission line inside the base, and the load. Finally, the effective efficiency correction factor is calculated.

[0031] In one embodiment of the present invention, when using a coaxial microwave millimeter-wave power reference calibration power sensor, the total steady-state temperature rise potential after adding radio frequency power is the sum of the thermoelectric potentials generated by the independent action of each heating element, which can be expressed as:

[0032] in, For the total temperature rise potential, The thermoelectric potential generated by the insulation section, The thermoelectric potential generated by the transmission lines inside the seat, The thermoelectric potential contributed by the load as it travels along a fast path. The thermoelectric potential contributed by the load through the slow path; therefore, the thermal contributions of the insulation section and the transmission line within the seat, which need to be separated, can be expressed as:

[0033] The thermoelectric potential generated by the load acting alone after the addition of radio frequency power is unknown, but the steady-state thermoelectric potential generated by the load acting alone when DC power is added can be expressed as:

[0034] If it can be achieved The target value can be obtained by subtracting a suitable DC transient temperature rise potential from the RF transient temperature rise potential. That is, the contribution of load heating is deducted. However, the RF transient temperature rise potential is greater than the load contribution during the RF experiment. In order to perform the peeling calculation, the accurate DC transient temperature rise potential must be found. Therefore, the DC transient temperature rise potential needs to be compressed. However, the compression cannot be done in one step. It is done step by step. Therefore, this process is called iteration.

[0035] The iterative algorithm of this invention finds the optimal DC steady-state temperature rise potential and uses the normalized DC transient thermoelectric potential change curve as the initial reference curve. The steady-state temperature rise potential of radio frequency is taken as the steady-state value. Let A be the thermoelectric potential of the insulation section and the transmission line inside the seat. The convergence reference curve is obtained by separating the thermoelectric potential from the steady-state value through an iterative algorithm. In the first iteration, the difference between the early-stage RF transient temperature rise potential in the RF transient thermoelectric potential change curve and the early-stage DC transient temperature rise potential in the initial reference curve is calculated, and the maximum value obtained is the difference value of the first iteration. The expression is as follows:

[0036] Through the first iteration difference The new reference curve for the first iteration can then be calculated. The expression is as follows:

[0037] in, This is the steady-state value. This is the compression factor for the first iteration. The thermoelectric potential generated by the insulation section in the first iteration. For the first Thermoelectric potential generated by the transmission line within the next iteration seat. This is the radio frequency temperature rise potential curve.

[0038] In the second iteration, the steady-state value is subtracted from the new reference curve from the first iteration to obtain the difference for the second iteration. The expression is as follows:

[0039] Through the second iteration difference The new reference curve for the second iteration can then be calculated. The expression is as follows:

[0040] Therefore, after the first The next iteration is calculated when the following condition is met: hour, For the first The difference in the next iteration. For the first The difference in the next iteration. The convergence threshold can be set to 0.0001, which yields a convergence reference curve. The expression for the convergence reference curve is as follows:

[0041]

[0042] in, For the first The new reference curve for the next iteration As the initial reference curve, This is the steady-state value. For the first The difference in the next iteration. For the first Compression coefficient of the next iteration For the first The thermoelectric potential generated by the insulation section in the next iteration For the first Thermoelectric potential generated by the transmission line within the next iteration seat. This is the radio frequency temperature rise potential curve.

[0043] In one embodiment of the present invention, the in-seat transmission line loss of the power sensor is calculated based on the convergence reference curve to obtain an effective efficiency correction factor.

[0044] according to From the definition, we can obtain:

[0045] After the iterative algorithm of this invention is completed, Substituting the values, we get:

[0046] The approximation is:

[0047] in, This refers to the power loss ratio of the transmission line within the power sensor. The result comes from the evaluation of the power loss of the internal transmission lines of the sensor. It can be taken from the statistical average of the calibration results of multiple power sensors of the same type. Each power sensor's... These are all considered as a set of definite values ​​corresponding to the model number, thus the expression for the effective efficiency correction factor is obtained as follows:

[0048] in, As an effective efficiency correction factor, This is the thermal equivalent factor for power loss on the transmission line within the power sensor. This is the thermal equivalent factor for the power loss in the insulation section. This refers to the power loss ratio of the transmission line within the power sensor. The power loss ratio of the heat insulation section of the power sensor. This represents the steady-state value of the RF temperature rise potential curve. The steady-state value of the convergence reference curve.

[0049] The beneficial effects of this invention are as follows: This invention provides a calibration effective efficiency correction factor method that overcomes the bottleneck of traditional physical isolation methods failing in high-frequency scenarios. It extends the upper limit of coaxial microwave and millimeter-wave power benchmark calibration to higher frequency bands, providing traceability for high-frequency power benchmarks. By collecting thermal information from the temperature rise curve after adding radio frequency power, it uses an iterative algorithm to decouple the heat sources in the calorimeter and determine the effective efficiency correction factor, ultimately determining the effective efficiency of the power sensor being calibrated. This eliminates the need to prepare ideal short-circuit / open-circuit sockets and build complex physical isolation devices; the calibration effective efficiency correction factor can be achieved simply through conventional data acquisition and algorithms, simplifying the calibration process and reducing computational costs. Furthermore, this invention can be used with various coaxial connectors and a wide frequency range, expanding the frequency application scenarios.

Claims

1. A method for calibration of effective efficiency correction factors, characterized in that, Includes the following steps: Radio frequency power is input to the power sensor under calibration, and the radio frequency transient thermoelectric potential change curve is obtained by a millivoltmeter. The radio frequency steady-state temperature rise potential in the radio frequency transient thermoelectric potential change curve is taken as the steady-state value. DC power is input to the power sensor under test, and the DC transient thermoelectric potential change curve is acquired by a millivoltmeter. The DC transient thermoelectric potential change curve is then normalized to obtain an initial reference curve. Calculate the maximum difference between the early stage of the radio frequency transient temperature rise potential in the radio frequency transient thermoelectric potential change curve and the early stage of the DC transient temperature rise potential in the DC transient thermoelectric potential change curve, and use the ratio of the maximum difference value to the steady-state value as the compression coefficient. Based on the compression coefficient, the initial reference curve is compressed using an iterative algorithm. The thermoelectric potential of the heat insulation section and the thermoelectric potential of the transmission line inside the base of the power sensor are separated from the steady-state value to obtain the convergence reference curve. Based on the convergence reference curve, the transmission line loss within the power sensor is calculated to obtain the effective efficiency correction factor.

2. The calibration efficiency correction factor method according to claim 1, characterized in that, The expression for compressing the initial reference curve using an iterative algorithm is as follows: in, For the first The new reference curve for the next iteration As the initial reference curve, This is the steady-state value. For the first The difference in the next iteration. For the first Compression coefficient of the next iteration For the first The thermoelectric potential generated by the insulation section in the next iteration For the first Thermoelectric potential generated by the transmission line within the next iteration seat. This is the radio frequency temperature rise potential curve. The convergence criterion for the new reference curve is expressed as follows: in, For the first The difference in the next iteration. The convergence reference curve is obtained when the convergence criterion of the new reference curve is satisfied, which is the convergence threshold.

3. The calibration efficiency correction factor method according to claim 1, characterized in that, The expression for the effective efficiency correction factor is as follows: in, As an effective efficiency correction factor, This is the thermal equivalent factor for power loss on the transmission line within the power sensor. This is the thermal equivalent factor for the power loss in the insulation section. This refers to the power loss ratio of the transmission line within the power sensor. The power loss ratio of the heat insulation section of the power sensor. This represents the steady-state value of the RF temperature rise potential curve. To converge the steady-state value of the reference curve, This refers to the power loss on the transmission line within the power sensor. This is the net power loss of the power sensor. This represents the power loss of the insulation section.

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