Device and method for efficiently measuring microwave surface impedance of high-temperature superconducting film

Abstract

The invention discloses a device and method for efficiently measuring microwave surface impedance of a high-temperature superconducting thin film, and belongs to the technical field of electronics, the device comprises a test probe, a calibration probe, a metal plate and a sealing cavity, the open bottom end face of the test probe is a test plane, and the calibration probe and the test probe are identical in structure; the two are in mirror symmetry about a test plane; the microwave surface resistance of the metal plate is known; a calibration probe, a metal plate or a to-be-tested HTS film is detachably placed on a test plane, is covered by a sealing cavity, is placed at the working temperature of the to-be-tested HTS film and is subjected to no-load quality factor and resonance frequency tests respectively, and RS and XS of the front and back surfaces of the to-be-tested HTS film are calculated. According to the invention, the microwave surface impedance of the front side and the back side of the to-be-tested HTS film can be simultaneously tested, the accuracy of a test result is ensured, the test efficiency is greatly improved, and the device is suitable for large-scale industrial test of the HTS film and is suitable for widely used HTS films with the size of 2 inches and the size of above 2 inches.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronics, and particularly relates to a device and method for efficiently measuring the microwave surface impedance of high-temperature superconducting thin films. Background Art

[0002] Since the emergence of the worldwide research boom on high-temperature superconductors (HTS), as an application of high-temperature superconductors, high-temperature superconducting thin films have become a hot topic in the field of electronic materials research. HTS thin films have a very low microwave surface resistance R S and a surface penetration depth λ independent of frequency, and are mainly used to fabricate microwave passive devices such as resonators, filters, antennas, etc. The microwave surface reactance Z S As one of the most important parameters of HTS thin films, its value is closely related to the performance of high-temperature superconducting microwave passive devices. Therefore, it is particularly important to measure the microwave surface reactance Zs of HTS thin films.

[0003] Z S =R S +jXs, X S =ωμ 0 λ; where, R S is the microwave surface resistance, characterizing the microwave loss of the HTS thin film and reflecting the density of quasiparticles; X S is the microwave surface reactance, proportional to the magnetic penetration depth λ and reflecting the density of Cooper pairs. From its variation relationship with temperature, information about the superconducting energy gap can be obtained. Therefore, accurately measuring the microwave surface impedance (including R S and X S ) is of great significance for understanding the physical and electronic properties of materials, developing new materials, and designing superconducting electronic components.

[0004] Currently, the test method of HTS thin films in the R S international test standard is the dual dielectric resonator method, and this method adopts two resonator structures as shown in Figure 1 . Each resonator is composed of two HTS thin films and a sapphire dielectric column therebetween. The two sapphire dielectric columns have the same dielectric constant ε, loss tangent tanδ, and diameter d, and the heights are h and 3h respectively, and their resonance modes are TE 011 and TE 013 . However, this method requires two temperature cycles for the two resonators respectively, that is, two temperature cycles for the HTS thin film to be measured, in order to obtain the R S, the testing process is time-consuming. For example, during testing, the testing device needs to be immersed in liquid nitrogen to cool down the HTS thin film to be tested using liquid nitrogen. After the test is completed, the testing device needs to be reheated to room temperature. This process is one temperature cycle and takes at least one hour. Moreover, the result of this method of testing is the average value of two HTS thin films to be tested. If we want to obtain the R of one side of a single sample S , at least three superconducting samples are required, and six temperature cycles are carried out, resulting in low testing efficiency.

[0005] Generally, for the measurement of R S and X S of HTS thin films, the same resonant structure needs to be used. Therefore, for the measurement of X S of HTS thin films, the dielectric resonator method is generally adopted internationally at present, as Figure 2 shown. By measuring the relationship between the resonant frequency f 0 of the entire resonant device and the change in temperature, the X S of the HTS thin film to be tested can be obtained. As Figure 2 (a) shows, first, metal plates of good conductors are loaded at both ends of the sapphire dielectric column, and the relationship between the resonant frequency of the entire resonant device and the change in temperature f 1 (T) is measured; then the metal plates are replaced with the HTS thin film to be tested, as Figure 2 (b) shows, and the relationship between the resonant frequency of the entire resonant device and the change in temperature f 2 (T) is measured. Finally, the difference between f 1 (T) and f 2 (T) is taken to calculate X S . However, this method introduces test errors caused by the metal plates during the testing process. Therefore, it is also necessary to separately test the relationship between the microwave surface reactance X S of the metal plates and the change in temperature, that is, three heating / cooling processes are required to measure the X S of the HTS thin film to be tested, and the testing efficiency is also low.

[0006] However, the above method can only measure the microwave surface impedance of one side of the HTS thin film to be tested, and currently, no method has been proposed to simultaneously measure the microwave surface impedance of both the front and back sides of the HTS thin film to be tested. Summary of the Invention

[0007] Aiming at the problem of low testing efficiency of the microwave surface impedance of the existing HTS thin film to be tested, the present invention provides a device and method for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film, which can simultaneously measure the microwave surface impedance of both the front and back sides of the HTS thin film to be tested. While ensuring the accuracy of the test results, the testing efficiency is greatly improved, which is suitable for large-scale industrial testing of HTS thin films and applicable to HTS thin films with a size of 2 inches and above that are widely used.

[0008] The technical solution adopted by the present invention is as follows:

[0009] An apparatus for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film, comprising a test probe, a calibration probe, a metal plate, and a sealed cavity;

[0010] The open bottom end face of the test probe is a test plane. The calibration probe has the same structure as the test probe, and the two are mirror-symmetric with respect to the test plane;

[0011] The microwave surface resistance of the metal plate is known;

[0012] The sealed cavity is used to cover the test plane;

[0013] By detachably placing the calibration probe, the metal plate, or the HTS thin film to be measured on the test plane, covering it with the sealed cavity, and performing unloaded quality factor tests respectively below the operating temperature of the HTS thin film to be measured, the microwave surface resistance R S and microwave surface reactance X S .

[0014] Further, the test probe includes a shield cavity with an open bottom end face, a dielectric column, a dielectric clamping ring, an input coupling structure, and an output coupling structure; the dielectric column is located at the center inside the shield cavity and is fixed to the shield cavity through the dielectric clamping ring; the bottom end face of the dielectric column and the bottom end face of the shield cavity are in the same plane, jointly constituting the test plane of the test probe; the input coupling structure and the output coupling structure are symmetrically distributed on both sides of the shield cavity.

[0015] Further, the shield cavity, the dielectric column, and the dielectric clamping ring are coaxial.

[0016] Further, both the input coupling structure and the output coupling structure adopt a coupling ring structure, and the plane where the coupling ring is located is parallel to the test plane.

[0017] Further, the shield cavity is made of brass as the processing material, and the surface treatment uses a silver plating process; the dielectric column uses a high-Q material with low loss and high dielectric constant, such as sapphire; the dielectric clamping ring uses a low-loss material with low dielectric constant, such as nylon, polytetrafluoroethylene, etc.

[0018] Further, the diameter of the HTS thin film to be measured is more than 2 inches, and the film thickness is not less than 200 nm.

[0019] Further, the method for efficiently measuring the microwave surface resistance of a high-temperature superconducting thin film specifically includes the following steps:

[0020] Step A1: Load the calibration probe onto the bottom end face of the test probe. The two are mirror-symmetric with respect to the test plane. Then cover the calibration probe with a sealed chamber. After sealing, introduce a protective gas. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and measure the unloaded quality factor Q 0H ;

[0021] Step A2: Heat the test device obtained in Step A1 to room temperature and remove the calibration probe. Then load a metal plate with a microwave surface resistance of R SN onto the bottom end face of the test probe. Cover the metal plate with a sealed chamber. After sealing, introduce a protective gas. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and measure the unloaded quality factor Q 0N ;

[0022] Step A3: Heat the test device obtained in Step A2 to room temperature and remove the metal plate. Then load the front side of the HTS thin film to be measured onto the bottom end face of the test probe, and then load the calibration probe onto the back side of the HTS thin film to be measured. The test probe and the calibration probe are mirror-symmetric with respect to the HTS thin film to be measured. Cover the calibration probe with a sealed chamber. After sealing, introduce a protective gas. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and respectively measure the unloaded quality factor Q 0T of the test probe and the unloaded quality factor Q 0C of the calibration probe;

[0023] Step A4: According to the formula

[0024]

[0025] calculate the microwave surface resistance R S1 of the front side of the HTS thin film to be measured;

[0026] Step A5: According to the formula

[0027]

[0028] calculate the microwave surface resistance R S2 of the back side of the HTS thin film to be measured.

[0029] Furthermore, by performing only one temperature cycle on the HTS thin film to be measured, the microwave surface resistances of both the front and back sides of the HTS thin film to be measured can be measured simultaneously; and for other HTS thin films to be measured, it is only necessary to repeat Steps A3 - A5, that is, perform one temperature cycle, to simultaneously measure the microwave surface resistances of both the front and back sides of the HTS thin film to be measured.

[0030] Further, the method for efficiently measuring the microwave surface reactance of a high-temperature superconducting thin film specifically includes the following steps:

[0031] Step B1: Load the calibration probe onto the bottom end face of the test probe. The two are mirror-symmetrical with respect to the test plane. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and measure the unloaded quality factor Q 0H Variation curve of Q with temperature T 0H (T), and the resonance frequency f 01 Variation curve of f with temperature T 01 (T). This step is called calibration process one;

[0032] Step B2: Heat the test device obtained in step B1 to room temperature and remove the calibration probe; then load the metal plate onto the bottom end face of the test probe. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and test to obtain the unloaded quality factor Q 0N Variation curve of Q with temperature T 0N (T). This step is called calibration process two;

[0033] Step B3: Heat the test device obtained in step B2 to room temperature and remove the metal plate; then load the front side of the HTS thin film to be measured onto the bottom end face of the test probe, and load the calibration probe onto the back side of the HTS thin film to be measured. The test probe and the calibration probe are mirror-symmetrical with respect to the HTS thin film to be measured. Place the obtained test device below the operating temperature of the HTS thin film to be measured, and respectively test to obtain the unloaded quality factor Q 0T Variation curve of Q with temperature T 0T (T), the resonance frequency f of the test probe 0T Variation curve of f with temperature T 0T (T), the unloaded quality factor Q of the calibration probe 0C Variation curve of Q with temperature T 0C (T), and the resonance frequency f of the calibration probe 0C Variation curve of f with temperature T 0C (T);

[0034] Step B4: Calculate the front-side microwave surface resistance R c of the HTS thin film to be measured at the quench temperature T S1 (T c );

[0035] According to the formula

[0036]

[0037] Calculate the relative value ΔX S1 (T) of the front-side microwave surface reactance of the HTS thin film to be measured varying with temperature T;

[0038] In the formula, T min is the lowest test temperature; f 0T (T min ) is Tmin The resonant frequency f of the test probe under 0T ; f 01 (T min ) is the resonant frequency f under T min ; 01 ;

[0039] Since the absolute value X S1 (T) of the microwave surface reactance of the front side of the HTS film to be measured changes with temperature and ΔX S1 (T) exist

[0040] ΔX S1 (T) = X S1 (T) - X S1 (T min ) (26)

[0041] And when the HTS film to be measured quenches, it satisfies

[0042] X S1 (T C ) = R S1 (T C ) (5)

[0043] Calculate X S1 (T);

[0044] In the formula, X S1 (T min ) is the microwave surface reactance of the front side of the HTS film to be measured at temperature T min ; X S1 (T c ) is the microwave surface reactance of the front side of the HTS film to be measured at T c ;

[0045] Step B5, calculate the reverse microwave surface resistance R c of the HTS film to be measured at T S2 (T c );

[0046] According to the formula

[0047]

[0048] Calculate the relative value ΔX S2 (T) of the reverse microwave surface reactance of the HTS film to be measured changing with temperature T;

[0049] In the formula, f 0C (T min ) is the calibration probe resonant frequency f at T min ; 0C ;

[0050] Due to the absolute value X of the microwave surface reactance of the reverse side of the HTS thin film to be measured varying with temperature S2 (T) and ΔX S2 (T) exist

[0051] ΔX S2 (T) = X S2 (T) - X S2 (T min ) (27)

[0052] And when the HTS thin film to be measured quenches, it satisfies

[0053] X S2 (T C ) = R S2 (T C ) (8)

[0054] Calculate to obtain X S2 (T);

[0055] In the formula, X S2 (T min ) is the microwave surface reactance of the reverse side of the HTS thin film to be measured at temperature T min ; X S2 (T c ) is the microwave surface reactance of the reverse side of the HTS thin film to be measured at T c .

[0056] Furthermore, through two calibration processes, and only performing one heating / cooling process on the HTS thin film to be measured, the microwave surface reactances of both the front and back sides of the HTS thin film to be measured can be measured simultaneously; and for other HTS thin films to be measured, only by repeating steps B3 - B5, that is, performing one heating / cooling process, the microwave surface reactances of both the front and back sides of the HTS thin film to be measured can be measured simultaneously.

[0057] Further, the formula for calculating R S1 (T c ) in step B4 is:[[]]

[0058]

[0059] In the formula, R SN (T) is the microwave surface resistance of the metal plate varying with temperature T; Q 0T (T c ) is the unloaded quality factor Q c of the test probe at T 0T ; Q 0H (T c ) is the unloaded quality factor Q c at T 0H ; Q 0N (T c ) is Tc No-load quality factor Q under 0N ;

[0060] Calculating R in step B5 S2 (T c ) is given by the formula:

[0061]

[0062] Where Q 0C (T c ) is the no-load quality factor Q of the test probe under T c . 0C .

[0063] Furthermore, steps B1 - B3 complete the heating and cooling tests by loading the corresponding test device into the refrigerator.

[0064] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0065] The present invention proposes a device and method for efficiently measuring the microwave surface impedance of high-temperature superconducting thin films, called the improved mirror dielectric resonator method. On the one hand, compared with the national standard test method - the double dielectric resonator method, the present invention only needs to perform one temperature cycle on the HTS thin film to be measured, and can simultaneously measure the microwave surface resistance of both sides of the HTS thin film to be measured. While ensuring high test sensitivity and accuracy, it greatly improves the test efficiency and avoids film damage caused by repeatedly putting the HTS thin film to be measured into liquid nitrogen for testing. It is especially suitable for widely used HTS thin films with a size of 2 inches or more and is suitable for large-scale industrial testing. On the other hand, compared with the national standard test method - the dielectric resonator method, the present invention deducts the influence brought by the drift of the resonator frequency due to the change of the dielectric constant of the dielectric column with temperature through two calibration processes, reduces the test error, and ensures the accuracy of the test results. After that, only one heating / cooling process needs to be performed on the HTS thin film to be measured, and the microwave surface reactance of both sides of the HTS thin film to be measured can be simultaneously measured, greatly improving the test efficiency of the microwave surface reactance of the HTS thin film to be measured. Description of the Drawings

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0067] Figure 1 Schematic structural diagram of measuring microwave surface resistance by the double dielectric resonator method;

[0068] Figure 2 Schematic diagram of the structure for measuring microwave surface reactance by the dielectric resonator method; among them, (a) is the resonator structure loaded with a metal plate; (b) is the resonator structure loaded with the HTS thin film to be measured.

[0069] Figure 3 Cross-sectional structure diagram of the test probe in the device for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film proposed in Embodiment 1 of the present invention.

[0070] Figure 4 Cross-sectional structure diagram of the test device after the test probe in the device for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film proposed in Embodiment 1 of the present invention is loaded with a calibration probe.

[0071] Figure 5 Cross-sectional structure diagram of the test device after the test probe in the device for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film proposed in Embodiment 1 of the present invention is loaded with a metal plate.

[0072] Figure 6 Cross-sectional structure diagram of the test device after the test probe in the device for efficiently measuring the microwave surface impedance of a high-temperature superconducting thin film proposed in Embodiment 1 of the present invention is successively loaded with the HTS thin film to be measured and a calibration probe.

[0073] Figure 7 is the curve of the resonance frequency of the test device varying with temperature after the test probe in Embodiment 3 of the present invention is successively loaded with the HTS thin film to be measured and a calibration probe; among them, (a) is the curve corresponding to the front side of the HTS thin film to be measured; (b) is the curve corresponding to the back side of the HTS thin film to be measured.

[0074] Figure 8 Curve of the relationship between the relative value of the microwave surface reactance of the front and back sides of the HTS thin film to be measured measured in Embodiment 3 of the present invention and temperature.

[0075] Figure 9 Curve of the variation of the microwave surface resistance and the absolute value of the microwave surface reactance of the front and back sides of the HTS thin film to be measured measured in Embodiment 3 of the present invention with temperature.

[0076] The explanations of each mark in the drawings are as follows:

[0077] 1 - Test probe; 2 - Shielding cavity; 3 - Dielectric clamping ring; 4 - Dielectric column; 5 - Input coupling structure; 6 - Output coupling structure; 7 - Metal plate; 8 - Sealing cavity; 9 - Calibration probe; 10 - HTS thin film to be measured; 11 - Front side of the HTS thin film to be measured; 12 - Back side of the HTS thin film to be measured. Detailed implementation manners

[0078] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0079] There are no particular restrictions on the sources of all raw materials of the present invention, and they can be purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0080] There are no particular restrictions on the purity of all raw materials of the present invention. The present invention preferably adopts analytical pure or the conventional purity requirements in the field of atomic layer deposition.

[0081] All raw materials and process procedures of the present invention, their grades or abbreviations all belong to the conventional grades or abbreviations in the field, and each grade or abbreviation is clear and definite in the field of its related uses. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the grade, abbreviation and corresponding uses, or implement them with corresponding equipment.

[0082] The present invention will be further described in detail below in conjunction with examples:

[0083] Example 1

[0084] This example proposes a device for efficiently measuring the microwave surface impedance of high-temperature superconducting thin films, including a test probe 1, a calibration probe 9, a sealed cavity 8 and a metal plate 7.

[0085] The structure of the test probe 1 is as Figure 3 shown, including a shielding cavity 2 with an open bottom end face, a dielectric clamping ring 3, a dielectric column 4, an input coupling structure 5 and an output coupling structure 6; wherein, the dielectric column 4 is located inside the shielding cavity 2 and is fixed to the shielding cavity through the dielectric clamping ring 3; the bottom end face of the dielectric column 4 and the bottom end face of the shielding cavity 2 are in the same plane, jointly constituting the test plane of the test probe 1; the input coupling structure 5 and the output coupling structure 6 are arranged on both sides of the shielding cavity 2, symmetrically distributed, both adopting a coupling ring structure, and the plane where the coupling ring is located is parallel to the test plane of the test probe; the test probe 1, the dielectric column 4 and the dielectric clamping ring 3 are coaxial.

[0086] The sealed cavity 8 is used to cover the test plane.

[0087] The calibration probe 9 has exactly the same structure and size as the test probe 1; as Figure 4 shown, the calibration probe 9 can be loaded on the bottom end face of the test probe 1, and the two are mirror-symmetrical about the test plane. The sealed cavity 8 is detachably arranged on the extension of the bottom end face of the test probe 1 to cover the calibration probe 9.

[0088] The microwave surface resistance R of the metal plate 7 SNIt is known that in order to ensure the stability of the microwave surface resistance of the metal plate 7, the gold plating process is used for the surface treatment of the metal plate; as Figure 5 shown, the metal plate 7 can be loaded on the bottom end face of the test probe 1, and the sealing cavity 8 is detachably arranged on the extension of the bottom end face of the test probe 1 to cover the metal plate 7.

[0089] The diameter of the HTS thin film 10 to be measured is 2 inches or more, and the coating thickness d is 200 nm or more; as Figure 6 shown, the front side 11 of the HTS thin film to be measured is loaded on the bottom end face of the test probe 1, the calibration probe 9 is loaded onto the back side 12 of the HTS thin film to be measured, and the sealing cavity 8 is detachably arranged on the extension of the bottom end face of the test probe 1 to cover the calibration probe 9 and the HTS thin film 10 to be measured.

[0090] In this embodiment, both the test probe 1 and the calibration probe 9 are made of brass material, with a silver plating on the surface. The main cavity is a cylindrical structure, with a diameter of about 35 mm and a height of 10 mm; the dielectric column 4 is made of a high-Q material with low loss and high dielectric constant, specifically sapphire, and its surface must be polished, with a diameter of about 8 mm and a height of about 6 mm; the dielectric clamping ring 3 is made of a low-loss material with low dielectric constant, specifically polytetrafluoroethylene.

[0091] In this embodiment, the HTS thin film 10 to be measured and both the test probe 1 and the calibration probe 9 form a dielectric resonator with a working mode of TE 011 mode, with a working frequency of 12 GHz. The unloaded quality factor Q 0 of the dielectric resonator and the microwave surface resistance R S of the HTS thin film 10 to be measured have the following relationship:

[0092]

[0093] where A and B are both geometric factors of the resonant cavity, independent of the microwave surface resistance R S of the HTS thin film 10 to be measured, and are determined by the measurement method.

[0094] Embodiment 2

[0095] Based on the device for efficiently measuring the microwave surface impedance of high-temperature superconducting thin films in Embodiment 1, this embodiment proposes a method for efficiently measuring the microwave surface resistance of high-temperature superconducting thin films, including the following steps:

[0096] Step A1: Load the calibration probe 9 onto the bottom end face of the test probe 1, and the two are mirror-symmetrical with respect to the test plane. The resistance R Sis 0; The calibration probe 9 is covered by the sealing cavity 8, specifically covering the bottom end faces of the calibration probe 9 and the test probe 1. After sealing, a protective gas is introduced, and the sealing cavity 8 of the obtained test device is immersed in liquid nitrogen, that is, placed at a temperature lower than the operating temperature (i.e., the quench temperature T c ) of the HTS thin film 10 to be measured. Connect the test instrument, and measure the unloaded quality factor Q 0H ;

[0097] According to the formula

[0098]

[0099] the A value of the improved image dielectric resonator can be obtained;

[0100] Step A2: Heat the test device obtained in Step A1 to room temperature, and remove the calibration probe 9; then load the metal plate 7 with a microwave surface resistance of R SN onto the bottom end face of the test probe 1, and cover the metal plate 7 with the sealing cavity 8, specifically covering the bottom end faces of the metal plate 7 and the test probe 1. After sealing, a protective gas is introduced, and the sealing cavity 8 of the obtained test device is immersed in liquid nitrogen, that is, placed at a temperature lower than the operating temperature of the HTS thin film 10 to be measured. Connect the test instrument, and measure the unloaded quality factor Q 0N ;

[0101] According to the formula

[0102]

[0103] the B value of the improved image dielectric resonator can be obtained;

[0104] Step A3: Heat the test device obtained in Step A2 to room temperature, and remove the metal plate 7; then load the front side 11 of the HTS thin film to be measured onto the bottom end face of the test probe 1, and then load the calibration probe 9 onto the back side 12 of the HTS thin film to be measured. The test probe 1 and the calibration probe 9 are mirror-symmetrical with respect to the HTS thin film 10 to be measured. Cover the calibration probe 9 with the sealing cavity 8, specifically covering the bottom end faces of the calibration probe 9 and the test probe 1. After sealing, a protective gas is introduced, and the sealing cavity 8 of the obtained test device is immersed in liquid nitrogen, that is, placed at a temperature lower than the operating temperature of the HTS thin film 10 to be measured. Connect the test instrument, and respectively measure the unloaded quality factor Q 0T of the test probe and the unloaded quality factor Q 0C of the calibration probe;

[0105] Step A4: According to the formula

[0106]

[0107] calculate to obtain the microwave surface resistance R c of the front side 11 of the HTS thin film to be measured at the quench temperature TS1 ;

[0108] Step A5. According to the formula

[0109]

[0110] calculate to obtain the quench temperature T c of the reverse side 12 of the HTS thin film to be measured under the following S2 .

[0111] Furthermore, by only performing one temperature cycle on the HTS thin film 10 to be measured, the microwave surface resistances of both the front and back sides of the HTS thin film 10 to be measured can be measured simultaneously; and for other HTS thin films to be measured, only need to repeat steps A3 - A5, that is, perform one temperature cycle, then the microwave surface resistances of both the front and back sides of the HTS thin film to be measured can be measured simultaneously.

[0112] In step 1, if the tangent of the loss angle tanδ of the dielectric column 4 used in the test probe 1 and the calibration probe 9 is different, it will cause asymmetry between the test probe 1 and the calibration probe 9, resulting in R S ≠0 at the mirror surface. R S = 0 at the mirror surface is the theoretical basis for accurately calculating the value of A, and the calculation of the value of B is also based on the premise that A is an accurate value. Therefore, verifying whether R S at the mirror surface is 0 can verify whether the model and theoretical derivation of the method for efficiently measuring the microwave surface resistance of high - temperature superconducting thin films proposed in this embodiment are correct.

[0113] Further, in order to verify whether R S at the mirror surface of the device used in this embodiment is 0, that is, the consistency of the tangent of the loss angle tanδ of the dielectric column 4 used in the test probe 1 and the calibration probe 9, step A6 is given based on step A3, and then the microwave surface resistances of both the front and back sides of the HTS thin film 10 to be measured are calculated respectively to compare the differences in the test results of measuring the same side of the HTS thin film 10 with the test probe 1 and the calibration probe 9 respectively. The specific operations are as follows:

[0114] Step A6. Flip the HTS thin film 10 in step A3, that is, load the reverse side 12 of the HTS thin film to be measured onto the bottom end face of the test probe 1, then load the calibration probe 9 onto the front side 11 of the HTS thin film to be measured. The test probe 1 and the calibration probe 9 are mirror - symmetric with respect to the HTS thin film 10, and use the sealed cavity 8 to cover the calibration probe 9. After sealing, introduce a protective gas, immerse the sealed cavity 8 of the obtained test device in liquid nitrogen, that is, place it below the operating temperature of the HTS thin film 10 to be measured, connect the test instrument, and respectively measure to obtain the unloaded quality factor Q' 0T of the test probe and the unloaded quality factor Q' 0C ;

[0115] Step A7. Calculate the microwave surface resistance R

[0116]

[0117] ′ of the front side of the HTS thin film to be measured according to the formula S ′ 1 ;

[0118] Step A8. Calculate the microwave surface resistance R

[0119]

[0120] ′ of the back side of the HTS thin film to be measured according to the formula S ′ 2 .

[0121] Furthermore, according to the measured values R S1 , R S2 , R S ′ 1 and R S ′ 2 , calculate the actual values of the microwave surface resistance of the front and back sides of the HTS thin film 10 to be measured. The derivation process is as follows:

[0122] In Figure 6 , the HTS thin film 10 to be measured and the test probe 1 and the calibration probe 9 respectively form two upper and lower dielectric resonators. The unloaded quality factor Q 0 of the dielectric resonator has the following relationship with the loss inside the corresponding dielectric resonator

[0123]

[0124] where ω 0 is the resonant angular frequency; P m is the power consumed by the shielding cavity 2; P d is the power consumed by the corresponding dielectric column 4 in the two upper and lower dielectric resonators; P sr is the power consumed by the dielectric clamping ring 3; P s is the power consumed by the microwave surface resistance R S of the HTS thin film 10 to be measured; W is the average energy stored in the resonant cavity in one resonant period in the TE 011 mode.

[0125] According to formula (9), denote

[0126]

[0127]

[0128] In Figure 4Among them, when considering the test probe 1 alone, its unloaded quality factor Q T The relationship with the internal power loss of the probe

[0129]

[0130] Where P T = P m + P dT + P sr P dT is the power consumed by the dielectric column 4 of the test probe 1.

[0131] In Figure 4 when considering the calibration probe 9 alone, its unloaded quality factor Q C The relationship with the internal power loss of the probe

[0132]

[0133] Where P C = P m + P dC + P sr P dC is the power consumed by the dielectric column 4 of the calibration probe 9.

[0134] Since the loss tangent of the dielectric column 4 of the test probe 1 and the calibration probe 9 is different, the consumed power is also different. Therefore, P dT ≠ P dC .

[0135] In Figure 4 for the entire test device, its unloaded quality factor Q 0H

[0136]

[0137] Therefore, from formulas (17) to (19), formula (20) can be obtained

[0138]

[0139] In Figure 6 after loading the HTS thin film 10 to be measured, when considering the dielectric resonator formed by the front side 11 of the HTS thin film to be measured and the test probe 1 alone, its unloaded quality factor Q 0T

[0140]

[0141] In Figure 6 after turning over the HTS thin film 10 to be measured, when considering the dielectric resonator formed by the front side 11 of the HTS thin film to be measured and the calibration probe 9 alone, its unloaded quality factor Q' 0C

[0142]

[0143] Therefore, from formulas (1), (13), and (20) - (22), the microwave surface resistance R of the front side of the HTS thin film to be measured can be calculated. S The actual value is

[0144]

[0145] According to formulas (1) and (13), the relationship between the actual value and the measured value of the microwave surface resistance R of the front side of the HTS thin film to be measured can be obtained. S The relationship between the actual value and the measured value of

[0146]

[0147] That is, the actual value of the microwave surface resistance R of the front side of the HTS thin film to be measured S is the average value of the measured values obtained by measuring with the test probe 1 and the calibration probe 9 respectively.

[0148] Similarly, the relationship between the actual value and the measured value of the microwave surface resistance R of the back side of the HTS thin film to be measured can be obtained. S The relationship between the actual value and the measured value of

[0149]

[0150] Using the method for efficiently measuring the microwave surface resistance of a high-temperature superconducting thin film described in this embodiment, the front and back sides of the same HTS thin film 10 to be measured are measured 6 times each in a liquid nitrogen environment using the test probe 1 and the calibration probe 9, and the obtained R S The test results are shown in Table 1.

[0151] For the front and back sides of the HTS thin film 10 to be measured, the two sets of data with the largest difference in the test results obtained by using the test probe 1 and the calibration probe 9 respectively are compared, and using formulas (24) and (25), the relative deviation between the average value (considered as the actual value) and the measured value of R is compared, as shown in Table 2. S The average value (considered as the actual value) and the relative deviation of the measured value are shown in Table 2.

[0152] The six test results obtained by using the test probe 1 and the calibration probe 9 respectively for the same side of the HTS thin film 10 to be measured are sorted again, and the standard deviation (precision) in the national standard GB / T 22586 - 2018 is used to measure the test error of the measured value, as shown in Table 3.

[0153] It can be found that for the same side of the same HTS thin film 10 to be measured, whether the test results are verified by the method for efficiently measuring the microwave surface resistance of high-temperature superconducting thin films described in this embodiment, or the standard deviation in the national standard GB / T 22586-2018 is used to measure the test error (generally required not to exceed 20%), when using the test probe 1 and the calibration probe 9 to measure R S the relative deviation of the results is very small, all within 6%, indicating that the method for efficiently measuring the microwave surface resistance of high-temperature superconducting thin films described in this embodiment has high test accuracy and repeatability.

[0154] Table 1

[0155]

[0156] Table 2

[0157]

[0158]

[0159] Table 3

[0160]

[0161] The method for efficiently measuring the microwave surface resistance of high-temperature superconducting thin films described in this embodiment has outstanding advantages compared with the test methods in international standards. Specifically: The dual dielectric resonator method requires two temperature cycles, and the test result is the average value of R of two HTS thin films to be measured. It is necessary to exchange the HTS thin films to be measured multiple times to obtain the R of a single sample S , with low test efficiency. And this test method does not consider the error introduced by different radial radiation losses of TE S and TE 011 and TE 013 In one temperature cycle of the HTS thin film 10 to be measured, the method for efficiently measuring the microwave surface resistance of high-temperature superconducting thin films described in this embodiment can measure the R of the front and back sides of a single HTS thin film 10 to be measured S , and gives a method to verify the test error between the test value and the actual value of R S , which not only improves the test efficiency but also ensures the accuracy of the test results, and is suitable for large-scale industrial testing.

[0162] Example 3

[0163] Based on the device for efficiently measuring the microwave surface impedance of high-temperature superconducting thin films in Example 1, this embodiment proposes a method for efficiently measuring the microwave surface reactance of high-temperature superconducting thin films. Among them, the resonant frequency f of the dielectric resonator formed by the HTS thin film 10 to be measured, the test probe 1 and the calibration probe 9 0The relative value ΔX of the microwave surface reactance of the HTS thin film 10 to be measured S The relationship with the temperature T is as follows:

[0164]

[0165] In the formula, A S is determined by the electromagnetic field distribution inside the resonator and has nothing to do with the HTS thin film 10 to be measured. In this embodiment, the value of A S is equal to B; Δf(T) is the frequency shift caused by the change of the frequency of the HTS thin film 10 to be measured with the temperature T; f 0 is the resonance frequency of the dielectric resonator when working at the lowest test temperature.

[0166] The method for efficiently measuring the microwave surface reactance of a high-temperature superconducting thin film proposed in this embodiment specifically includes the following steps:

[0167] Step B1: Load the calibration probe 9 onto the bottom end face of the test probe 1. The two are mirror-symmetrical about the test plane. Load the obtained test device into the refrigerator, connect the test instrument, and use the refrigerator to raise and lower the temperature, that is, place it below the working temperature of the HTS thin film 10 to be measured, and measure the unloaded quality factor Q 0H The curve of Q 0H changing with the temperature T, Q 01 The curve of f 01 changing with the temperature T, f

[0168] This step is called the first calibration process;

[0168] Step B2: Heat the test device obtained in step B1 to room temperature and remove the calibration probe 9; then load the metal plate 7 onto the bottom end face of the test probe 1. Load the obtained test device into the refrigerator, connect the test instrument, and use the refrigerator to raise and lower the temperature, that is, place it below the working temperature of the HTS thin film 10 to be measured, and test and obtain the unloaded quality factor Q 0N The curve of Q 0N changing with the temperature T, Q 0T This step is called the second calibration process;

[0169] Step B3: Heat the test device obtained in step B2 to room temperature and remove the metal plate 7; then load the front side 11 of the HTS thin film to be measured onto the bottom end face of the test probe 1, and then load the calibration probe 9 onto the back side 12 of the HTS thin film to be measured. The test probe 1 and the calibration probe 9 are mirror-symmetrical about the HTS thin film 10 to be measured. Load the obtained test device into the refrigerator, connect the test instrument, and use the refrigerator to raise and lower the temperature, that is, place it below the working temperature of the HTS thin film 10 to be measured, and respectively test and obtain the unloaded quality factor Q 0T The curve of Q 0T changing with the temperature T, Q 0T The curve of the resonance frequency f 0T changing with the temperature T, f0T (T), the unloaded quality factor Q of the calibration probe 0C The curve of Q varying with temperature T 0C (T), and the resonant frequency f of the calibration probe 0C The curve of f varying with temperature T 0C (T);

[0170] Step B4. Calculate the front microwave surface resistance R of the HTS thin film 10 to be measured at the quench temperature T c The formula is as follows: S1 (T c ) is:

[0171]

[0172] In the formula, R SN (T C ) is the microwave surface resistance of the metal plate at T c ; Q 0T (T c ) is the unloaded quality factor Q of the test probe at T c ; Q 0T ; Q 0H (T c ) is the unloaded quality factor Q at T c ; Q 0H ; Q 0N (T c ) is the unloaded quality factor Q at T c ; 0N ;

[0173] According to the formula

[0174]

[0175] Calculate the relative value ΔX of the front microwave surface reactance of the HTS thin film 11 to be measured varying with temperature T S1 (T);

[0176] In the formula, T min is the lowest test temperature; f 0T (T min ) is the resonant frequency f of the test probe 1 at T min ; f 0T ; f 01 (T min ) is the resonant frequency f at T min ; 01 ;

[0177] Since the absolute value X S1 (T) of the front microwave surface reactance of the HTS thin film 11 to be measured varying with temperature and ΔX S1 (T) have

[0178] ΔX S1 (T) = X S1 (T) - X S1 (T min ) (26)

[0179] And when the HTS thin film 10 to be measured quenches, it satisfies

[0180] X S1 (T C ) = R S1 (T C ) (5)

[0181] Calculate to obtain X S1 (T);

[0182] In the formula, X S1 (T min ) is the microwave surface reactance of the front side 11 of the HTS thin film to be measured at temperature T min ; X S1 (T c ) is the microwave surface reactance of the front side 11 of the HTS thin film to be measured at T c ;

[0183] Step B5, calculate the reverse microwave surface resistance R c of the HTS thin film 10 to be measured at T S2 (T c ), and the formula is:

[0184]

[0185] In the formula, Q 0C (T c ) is the unloaded quality factor Q c of the test probe at T 0C ;

[0186] According to the formula

[0187]

[0188] Calculate to obtain the relative value ΔX S2 (T) of the reverse microwave surface reactance of the HTS thin film to be measured varying with temperature T;

[0189] In the formula, f 0C (T min ) is the resonance frequency f min of the calibration probe 9 at T 0C ;

[0190] Since the absolute value X S2 (T) of the reverse microwave surface reactance of the HTS thin film to be measured varying with temperature and ΔX S2(T) exists

[0191] ΔX S2 (T) = X S2 (T) - X S2 (T min ) (27)

[0192] And when the HTS thin film 10 to be measured quenches, it satisfies

[0193] X S2 (T C ) = R S2 (T C ) (8)

[0194] Calculate to obtain X S2 (T);

[0195] In the formula, X S2 (T min ) is the microwave surface reactance of the back side 12 of the HTS thin film to be measured at temperature T min ; X S2 (T c ) is the microwave surface reactance of the back side 12 of the HTS thin film to be measured at T c .

[0196] Furthermore, through two calibration processes, and only performing one heating / cooling process on the HTS thin film 10 to be measured, the microwave surface reactances of both the front and back sides of the HTS thin film 10 to be measured can be measured simultaneously; and for other HTS thin films to be measured, only need to repeat steps B3 - B5, that is, perform one heating / cooling process, then the microwave surface reactances of both the front and back sides of the HTS thin film to be measured can be measured simultaneously.

[0197] In this embodiment, the interval of the test temperature is 1K, the lowest test temperature is 77K, and the highest test temperature is the quench temperature of the HTS thin film 10 to be measured. Among them, the quench temperature of the front side 11 of the HTS thin film to be measured is 106K, and the quench temperature of the back side 12 of the HTS thin film to be measured is 102K.

[0198] Figure 7 is the curve of the resonant frequency ΔF varying with temperature of the test device with the test probe 1 alone loading the calibration probe 9 and the test device jointly loading the HTS thin film 10 to be measured and the calibration probe 9 in this embodiment, ΔF = f 0 (T) - f 0 (T min ). Further, (a) of Figure 7 is the curve corresponding to the front side 11 of the HTS thin film to be measured, where the curve ΔF corresponding to the test probe is ΔF 01 = f 01 (T) - f 01 (T min ), and the curve ΔF corresponding to the front side of the HTS thin film to be measured is ΔF0T = f 0T (T) - f 0T (T min ), and the curve ΔF corresponding to the difference between the two is ΔF = ΔF 0T -ΔF 01 . Figure 7(b) shows the curve corresponding to the reverse side 12 of the HTS thin film to be measured. Among them, the curve ΔF corresponding to the test probe is ΔF 01 = f 01 (T) - f 01 (T min ), and the curve ΔF corresponding to the reverse side of the HTS thin film to be measured is ΔF 0C = f 0C (T) - f 0C (T min ), and the curve ΔF corresponding to the difference between the two is ΔF = ΔF 0C -ΔF 01 .

[0199] Figure 8 This is the curve of the relationship between the relative value of the microwave surface reactance of the front and back sides of the HTS thin film 10 to be measured and the temperature measured in this embodiment. Figure 9 This is the curve of the change of the microwave surface resistance and the absolute value of the microwave surface reactance of the front and back sides of the HTS thin film 10 to be measured with temperature measured in this embodiment.

[0200] The curve ΔF corresponding to the front side 11 of the HTS thin film to be measured is shown in Figure 7(a). Using formula (4), the relative value ΔX S1 (T) of the microwave surface reactance of the front side 11 of the HTS thin film to be measured relative to the lowest test temperature can be obtained, as Figure 8 shown; similarly, the curve ΔF corresponding to the reverse side 12 of the HTS thin film to be measured is shown in Figure 7(b). Using formula (7), the relative value ΔX S2 (T) of the microwave surface reactance of the reverse side 12 of the HTS thin film to be measured relative to the lowest test temperature is calculated, as Figure 8 shown. Then, according to formulas (5) and (8) satisfied when the HTS thin film 10 quenches, the microwave surface reactance X S1 (T) of the front side 11 of the HTS thin film to be measured and the microwave surface reactance X S2 (T) of the reverse side 12 of the HTS thin film to be measured are calculated, as Figure 9 shown.

[0201] In summary, in this embodiment, after performing two calibrations by respectively loading the calibration probe 9 and the metal plate 7 on the test probe 1, during one heating / cooling process, the microwave surface reactance X of the front and back sides of the HTS thin film 10 to be measured can be obtained S, it greatly improves the test efficiency of the microwave surface reactance of HTS thin films and is suitable for large-scale industrial testing; in addition, through two calibration processes, the test error caused by the drift of the resonator frequency due to the change of the dielectric constant of the dielectric column with temperature can be deducted to ensure the accuracy of the test results.

[0202] In this article, specific examples are used to elaborate on the principles and implementation methods of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention, including the best mode, and also enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films, characterized in that: Includes test probe, calibration probe, metal plate and sealed chamber; The open bottom end surface of the test probe is a test plane, and the calibration probe and the test probe have the same structure, and the two are mirror-symmetrical about the test plane; The microwave surface resistance of the metal plate is known; The sealed cavity is used to cover the test plane; The calibration probe, metal plate or HTS film to be tested is detachably placed on the test plane and covered with a sealed cavity. The no-load quality factor and resonant frequency tests are performed below the working temperature of the HTS film to be tested. The microwave surface resistance R of the front and back sides of the HTS film to be tested is calculated. S and microwave surface reactance X S .

2. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 1, characterized in that: The test probe comprises a shielding cavity with an open bottom end surface, a dielectric column, a dielectric clamping ring, an input coupling structure and an output coupling structure; the dielectric column is located at the center of the shielding cavity and is fixed to the shielding cavity through the dielectric clamping ring; the bottom end surface of the dielectric column and the bottom end surface of the shielding cavity are in the same plane, together forming a test plane of the test probe; the input coupling structure and the output coupling structure are symmetrically distributed on both sides of the shielding cavity.

3. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 2, characterized in that: The shielding cavity, the dielectric column and the dielectric clamping ring are coaxial.

4. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 2, characterized in that: The input coupling structure and the output coupling structure both adopt coupling ring structures, and the plane where the coupling ring is located is parallel to the test plane.

5. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 2, characterized in that: The shielding cavity uses brass as a processing material, and the surface treatment uses a silver plating process; the material of the dielectric column is sapphire; the material of the dielectric clamping ring is nylon or polytetrafluoroethylene.

6. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 2, characterized in that: It is used to efficiently measure the microwave surface resistance of high-temperature superconducting thin films, and specifically includes the following steps: Step A1: Load the calibration probe onto the bottom end surface of the test probe. The two are mirror-symmetrical about the test plane. Use a sealed cavity to cover the calibration probe. After sealing, introduce protective gas. Place the obtained test device below the working temperature of the HTS film to be tested. Test to obtain the no-load quality factor Q 0H ; Step A2: Heat the test device obtained in step A1 to room temperature, remove the calibration probe, and then measure the microwave surface resistance R SN The metal plate is loaded onto the bottom surface of the test probe, and the metal plate is covered with a sealed cavity. After sealing, a protective gas is introduced. The obtained test device is placed below the working temperature of the HTS film to be tested, and the no-load quality factor Q is obtained by testing. 0N ; Step A3, heating the test device obtained in step A2 to room temperature, removing the metal plate; then loading the front side of the HTS film to be tested onto the bottom end face of the test probe, and then loading the calibration probe onto the back side of the HTS film to be tested, the test probe and the calibration probe are mirror-symmetrical about the HTS film to be tested, and a sealed cavity is used to cover the calibration probe, and after sealing, a protective gas is introduced, and the obtained test device is placed below the working temperature of the HTS film to be tested, and the no-load quality factor Q of the test probe is obtained by testing respectively. 0T And calibrate the probe unloaded quality factor Q 0C ; Step A4: According to the formula The microwave surface resistance R of the HTS film to be tested is calculated. S1 ; Step A5: According to the formula The microwave surface resistance R of the reverse side of the HTS film to be tested is calculated S2 .

7. The device for efficiently measuring microwave surface impedance of high-temperature superconducting thin films according to claim 2, characterized in that: It is used to efficiently measure the microwave surface reactance of high-temperature superconducting thin films, and specifically includes the following steps: Step B1: Load the calibration probe onto the bottom surface of the test probe, and the two are mirror-symmetrical about the test plane. Place the obtained test device below the working temperature of the HTS film to be tested, and measure the no-load quality factor Q 0H Curve Q changes with temperature T 0H (T), and the resonant frequency f 01 Curve f changes with temperature T 01 (T); Step B2: Heat the test device obtained in step B1 to room temperature and remove the calibration probe; then load the metal plate onto the bottom surface of the test probe, place the obtained test device below the working temperature of the HTS film to be tested, and test to obtain the no-load quality factor Q 0N Curve Q changes with temperature T 0N (T); Step B3, heat the test device obtained in step B2 to room temperature, remove the metal plate; then load the front side of the HTS film to be tested to the bottom end face of the test probe, and then load the calibration probe to the back side of the HTS film to be tested. The test probe and the calibration probe are mirror-symmetrical about the HTS film to be tested. Place the obtained test device below the working temperature of the HTS film to be tested, and test and obtain the no-load quality factor Q of the test probe respectively. 0T Curve Q changes with temperature T 0T (T), test probe resonant frequency f 0T Curve f changes with temperature T 0T (T), calibration probe unloaded quality factor Q 0C Curve Q changes with temperature T 0C (T), and the calibration probe resonant frequency f 0C Curve f changes with temperature T 0C (T); Step B4: Calculate the quench temperature T of the HTS film to be tested. c The surface resistance R of the microwave S1 (T c ); According to the formula The relative value ΔX of the microwave surface reactance of the HTS film to be tested changing with temperature T is calculated. S1 (T); Where, T min is the minimum test temperature; f 0T (T min ) is T min The test probe resonant frequency f 0T ;f 01 (T min ) is T min The resonant frequency f 01 ; Since the absolute value of the microwave surface reactance of the HTS film to be tested changes with temperature, X S1 (T) and ΔX S1 (T) Existence ΔX S1 (T)=X S1 (T)-X S1 (T min ) And the HTS film to be tested meets the following conditions when it fails: X S1 (T C )=R S1 (T C ) Calculate X S1 (T); In the formula, X S1 (T min ) is the temperature T min The microwave surface reactance of the HTS film under test; X S1 (T c ) is T c The microwave surface reactance of the front side of the HTS film under test; Step B5: Calculate the HTS film to be tested at T c The reverse microwave surface resistance R S2 (T c ); According to the formula The relative value ΔX of the microwave surface reactance of the back side of the HTS film to be tested as a function of temperature T is calculated. S2 (T); In the formula, f 0C (T min ) is T min The calibration probe resonant frequency f 0C ; Since the absolute value of the microwave surface reactance of the HTS film to be tested changes with temperature, X S2 (T) and ΔX S2 (T) Existence ΔX S2 (T)=X S2 (T)-X S2 (T min ) And the HTS film to be tested meets the following conditions when it fails: X S2 (T C )=R S2 (T C ) Calculate X S2 (T); In the formula, X S2 (T min ) is the temperature T min The microwave surface reactance of the reverse side of the HTS film under test; X S2 (T c ) is T c Microwave surface reactance of the back side of the HTS film under test.

8. The device for efficiently measuring microwave surface impedance of a high-temperature superconducting thin film according to claim 7, characterized in that: Calculate R in step B4 S1 (T c ) is: In the formula, R SN (T) is the microwave surface resistance of the metal plate that changes with temperature T; Q 0T (T c ) is T c The test probe is unloaded with a quality factor Q 0T ;Q 0H (T c ) is T c The no-load quality factor Q 0H ;Q 0N (T c ) is T c The no-load quality factor Q 0N ; Calculate R in step B5 S2 (T c ) is: In the formula, Q 0C (T c ) is T c The test probe is unloaded with a quality factor Q 0C .

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