Radio frequency probe calibration method and calibration device

Abstract

The present invention provides a radio frequency probe calibration method and calibration device, the device includes a radio frequency electric field measuring instrument, a rotating tray frame, a clamping rotating mechanism, a shear wave chamber, a radio frequency probe, a high frequency signal generator, a power amplifier, a high frequency millivoltmeter, an attenuator and a computer, the radio frequency electric field measuring instrument is installed on the rotating tray frame, the radio frequency electric field measuring instrument is connected to the radio frequency probe through a probe catheter; the probe catheter is installed on the clamping rotating mechanism, and the radio frequency probe is in the shear wave chamber; the output end of the high frequency signal generator is connected to the input end of the power amplifier, and the output end of the power amplifier is connected to one end of the shear wave chamber; the high frequency millivoltmeter is connected to the attenuator, and the attenuator is connected to the other end of the shear wave chamber; the radio frequency electric field measuring instrument is connected to the computer. The device structure has beautiful appearance, accurate and convenient operation, reduces labor intensity, and improves work efficiency and product qualification rate.

Description

Technical Field

[0001] The invention relates to the field of radio frequency probe calibration, and in particular to a radio frequency probe calibration method and a calibration device. Background Art

[0002] With the development of economic construction and the progress of science and technology, my country has made gratifying achievements in power equipment, communication networks, transportation, etc. The development of various fields and the application of advanced electronic equipment have made people's lives fast and convenient, which not only improved people's material and cultural living standards, but also brought us a new topic: how to measure and protect against electromagnetic radiation.

[0003] A large number of electronic devices also emit electromagnetic energy while operating normally, which may have adverse effects on other devices or even cause serious harm. This is electromagnetic interference. Under the conditions of limited time, space and limited frequency resources, the severity of electromagnetic interference has attracted widespread attention due to the increasing number of electrical and electronic equipment and the increasing intensity of use. Although the operating frequency of modern electronic equipment has been extended to the optical wave band, the frequently used frequency range is concentrated below 40GHz. Due to limited frequency resources, a large number of different types of electronic equipment have to reuse certain frequency bands, which makes it easy to cause mutual interference. As electronic technology develops rapidly towards integration, digitization, density and high speed, the sensitivity of transmitters and receivers has been greatly improved, and the interference level generated by electronic and electrical equipment is constantly increasing.

[0004] Modern electronic and electrical equipment or systems and the electromagnetic environment are like a pair of inseparable twin brothers. The higher the technology of the equipment or system, the more complex the electromagnetic environment it creates. At the same time, the complex electromagnetic environment places higher demands on the equipment. Electromagnetic interference is not limited to electrical and electronic equipment, but also involves natural interference sources, nuclear electromagnetic pulses, electrostatic discharge, the ecological effects of electromagnetic radiation on the human body, confidentiality breaches caused by electromagnetic leakage of information processing equipment, detection of electromagnetic radiation before earthquakes for pre-earthquake forecasts, and other issues.

[0005] Electromagnetic field radiation exceeding a certain intensity can cause dysfunction of the central nervous system and autonomic nervous system disorders, mainly sympathetic nervous fatigue and tension. Its clinical symptoms can be dizziness, insomnia, fatigue, memory loss, palpitations, headaches, limb pain, loss of appetite, hair loss, sweating, etc. Some people may also experience bradycardia, decreased blood pressure, arrhythmia, etc. Electromagnetic fields are silent, lightless, and odorless. People cannot feel them unless they are very strong. Therefore, this hazard is very "hidden" and is often not noticed or taken seriously by people. In order to protect people's health, my country has promulgated environmental and health standards related to electromagnetic field hazards, including: electromagnetic radiation protection regulations (GB8702-88), environmental electromagnetic wave health standards (GB9175-88), microwave radiation health standards in the workplace (GB10436-89), ultra-high frequency radiation health standards in the workplace (GB10437-89), etc. The state has formulated corresponding laws, regulations and national standards. For the management of electromagnetic radiation environment, the state has relatively systematic laws and regulations and standards. Wuhan Bihai Yuntian Technology Co., Ltd. has successfully developed a portable radio frequency electric field measuring instrument based on the corresponding laws, regulations and national standards. The successful development of this instrument provides an effective scientific basis for the law enforcement of government functional departments such as environmental monitoring, safety supervision, and occupational disease prevention and control, and is widely used in industrial and mining enterprises, labor protection, occupational disease prevention and control, environmental monitoring and other departments. The key to the production and manufacturing of this instrument is the instrument's sensor - the radio frequency probe. The sensor is not available in a ready-made commodity and must be developed by the manufacturer itself. It is necessary to study the calibration method of the radio frequency probe to solve the problems of inefficiency in the complicated calibration process, product consistency, and low accuracy. This is the problem to be solved by this invention / utility model patent. Summary of the invention

[0006] The purpose of the present invention is to provide a radio frequency probe calibration method and a calibration device, the device structure has beautiful appearance, accurate and convenient operation, reduces labor intensity, improves work efficiency and product qualification rate.

[0007] The technical solution of the present invention:

[0008] A radio frequency probe calibration device comprises a radio frequency electric field measuring instrument, a rotating tray frame, a clamping rotating mechanism, a shear wave chamber, a radio frequency probe, a high frequency signal generator, a power amplifier, a high frequency millivoltmeter, an attenuator and a computer.

[0009] The radio frequency electric field measuring instrument is installed on the rotating tray frame, and the radio frequency electric field measuring instrument is connected to the radio frequency probe through the probe catheter;

[0010] The probe catheter is installed on the clamping and rotating mechanism, the radio frequency probe is in the shear wave chamber, and the clamping and rotating mechanism drives the probe catheter to rotate, thereby driving the radio frequency probe to rotate in the shear wave chamber;

[0011] The output end of the high frequency signal generator is connected to the input end of the power amplifier, and the output end of the power amplifier is connected to one end of the shear wave chamber;

[0012] The high frequency millivoltmeter is connected to an attenuator, and the attenuator is connected to the other end of the shear wave chamber;

[0013] The radio frequency electric field measuring instrument is connected to a computer.

[0014] The rotating tray frame includes a chassis, a connecting seat is installed on the chassis, a supporting guide rod is installed on the connecting seat, a triangular bracket is installed on the supporting guide rod, a locking screw sleeve sleeved on the supporting guide rod is installed at the connection between the cross bar of the triangular bracket and the supporting guide rod, a sliding sleeve sleeved on the supporting guide rod is installed at the connection between the oblique support rod of the triangular bracket and the supporting guide rod, a locking screw sleeve is also arranged below the sliding sleeve, and the locking screw sleeve is locked by a butterfly screw, a deep groove ball bearing is installed at one end of the cross bar of the triangular bracket away from the supporting guide rod, the deep groove ball bearing is installed on the top end of the cross bar of the triangular bracket through an upper bearing support, and a rotating tray for supporting the radio frequency electric field measuring instrument is installed on the deep groove ball bearing.

[0015] The clamping and rotating mechanism includes a base plate installed above the transverse wave chamber, a positioning plate is welded below the base plate, a rotating disk is installed above the base plate, a vertical annular scale is marked on the outer circumference of the rotating disk by laser, a rotating support rod is installed on the rotating disk, the lower end of the rotating support rod is connected to the rotating disk, and the upper end is fixedly connected to the connecting plate, the connecting plate is fixedly connected to the clamping assembly, the clamping assembly clamps and locks the probe catheter of the radio frequency probe, a silicone sheath tube is also provided at the connection between the clamping assembly and the probe catheter of the radio frequency probe, and a horizontal angle dial is marked on the upper surface of the rotating disk by laser.

[0016] A lower bearing position is installed in the rotating disk, a second deep groove ball bearing is installed on the lower bearing position, and the rotating disk rotates around the second deep groove ball bearing.

[0017] The holding assembly includes two holding blocks, the right ends of the two holding blocks are respectively connected to two right ear plates, the two right ear plates are connected by hinges, the left ends of the two holding blocks are respectively connected to the rear left ear plate and the front left ear plate, and the locking slot is connected to the front left ear plate by rivets.

[0018] The bottom plate is also provided with a bottom plate angle scale which matches with the vertical annular scale and the horizontal angle scale.

[0019] The positioning plate is embedded in the square hole above the shear wave chamber to play a positioning role, preventing the clamping rotating mechanism from moving and rotating above the shear wave chamber, thereby ensuring that the tested radio frequency probe is in an effective uniform electric field area.

[0020] The power amplifier and the shear wave chamber as well as the attenuator and the shear wave chamber are all connected via N-type connectors.

[0021] A radio frequency probe calibration method comprises the following specific steps:

[0022] According to the above-mentioned radio frequency probe calibration device, connect various instruments and equipment, turn on the power, and preheat for 10 minutes for use;

[0023] Turn the pallet of the rotating pallet rack to above the clamping center of the clamping rotating mechanism;

[0024] Adjust the height of the tray, and fix the RF probe sensing test point at the center of the uniform electric field in the shear wave chamber;

[0025] Put on the silicone sheath tube at the clamping position of the RF probe;

[0026] The aerial plug of the RF probe passes through the central hole of the rotating tray and is inserted into the corresponding port of the RF electric field measuring instrument, and the RF electric field measuring instrument is placed on the rotating tray;

[0027] The RF probe hangs down naturally, is loaded into the clamping center of the rotating mechanism, and is locked for testing and calibration.

[0028] The radio frequency electric field measuring instrument is connected to the computer communication line;

[0029] Connect the radio frequency electric field measuring instrument and computer to the power source and start them up;

[0030] Adjust the knob of the high-frequency signal generator output until the high-frequency millivoltmeter displays 1000mV;

[0031] The rotating disk rotates to the 0° starting position, and a data is collected every 0.5°. The angle position of the strongest output signal point is recorded. There are 6 maximum value points in the rotation of 360°. Observe the data recorded by the computer and the data changes of the three axes of X, Y, and Z displayed by the radio frequency electric field measuring instrument, and record the angle position of the maximum extreme point of each axis, that is, record the angle values ​​of αX, αY, and αZ, which are the calibration point positions of the X, Y, and Z axes respectively;

[0032] At the calibration point of each axis, a signal is input every 25mV until the full scale is reached. The computer records the output signal data and fitting data to obtain the calibration curve. This is performed at the calibration points of the three axes in turn to obtain the three fitting curve equations of the three axes.

[0033] The computer imports the three fitting curve equations into the CPU of the radio frequency electric field measuring instrument;

[0034] Check its correctness and whether it meets the accuracy requirements;

[0035] After the calibration of a single instrument is completed, the calibrated RF probe is disassembled;

[0036] Proceed with the calibration of the next set of instruments in turn.

[0037] The method to check its correctness and whether it meets the accuracy requirements is to adjust the output of the high-frequency signal generator, and the detection points are:

[0038] Detection limit, 5% FS, 20% FS, 40% FS, 60% FS, 80% FS, 100% FS;

[0039] At each detection point, input the corresponding value, drive the RF probe to rotate through the rotating disk, rotate at any angle, observe the changes of the field strength Ex, Ey and Ez of each axis, and the comprehensive field strength E remains unchanged, that is, it is isotropic;

[0040] If the comprehensive field strength E and theoretical calculation meet the accuracy requirements, the product indicators are judged to be qualified.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) Due to the precise positioning of the device, a consistent standard source is provided for the calibration of batch products, which ensures the performance accuracy of the product, the consistency of batch products, and improves the interchangeability of products.

[0043] (2) The device is novel in design. Both the rotating disk and the rotating tray are designed to be connected with bearings, which are easy and flexible to adjust. The clamping center is designed to be concentric with the rotating disk, so that the measuring instrument connected to the probe can rotate around the axis without shaking. The rotating tray is driven to rotate by static friction to avoid external friction damage. By increasing the diameter of the rotating disk, the resolution of the angle dial can be improved, reducing the visual fatigue of the operator. The rotating disk is designed with a horizontal dial and a vertical dial, so that the operator can easily read the angle on the dial regardless of whether he is sitting or standing. The slot on the clamping assembly, in conjunction with the silicone sheath tube, is convenient for locking the clamping probe. The elasticity of the silicone sheath tube provides a clamping preload to prevent the probe from axial movement and prevents the probe catheter from being pinched.

[0044] (3) The device has a beautiful structure and appearance, and is accurate and convenient to operate, which reduces labor intensity and improves work efficiency and product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is the overall structural diagram of the present invention.

[0046] Figure 2 It is a structural schematic diagram of a rotating tray rack of the present invention.

[0047] Figure 3 The clamping and rotating mechanism of the present invention is schematically shown in FIG. Figure 1 .

[0048] Figure 4 The clamping and rotating mechanism of the present invention is schematically shown in FIG. Figure 2 .

[0049] Figure 5 The present invention Figure 4 AA direction schematic diagram.

[0050] Figure 6 It is a top view schematic diagram of the binding assembly of the present invention.

[0051] Figure 7 It is a front view schematic diagram of the binding assembly of the present invention.

[0052] Figure 8 It is a schematic diagram of the open state of the binding assembly of the present invention.

[0053] Fig. 9 It is a schematic diagram of the steps of connecting the binding assembly and the radio frequency probe of the present invention.

[0054] Fig.10 It is a schematic diagram of the angular position dial of the maximum extreme point of each axis of the radio frequency probe of the present invention.

[0055] Fig.11 It is the vi-α curve of each axis of the radio frequency probe of the present invention. DETAILED DESCRIPTION

[0056] 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.

[0057] In order to solve the problem of RF probe calibration, we first introduce the composition and measurement principle of RF probe. It consists of three vibrators, foam body, connecting rod and connecting aviation plug. The three vibrators form the X, Y and Z axes and are integrated into the foam body. This is the core part of the sensor.

[0058] The principle of measuring the radio frequency electric field is: the radio frequency electric field measurement sensor is connected to the radio frequency electric field measuring instrument host through an aerial plug, and can simultaneously detect the electric field strength in the three free axes of space X, Y, and Z. The radio frequency electric field measurement sensor is composed of three mutually orthogonal antennas. The sensor has a highly sensitive detector that transmits the signal to the host through a high-frequency dedicated aerial plug-in. After being processed and displayed by the host's amplifier and microprocessor, the electric field strength Ex, Ey, and Ez in the three free axes of X, Y, and Z are obtained. The comprehensive radio frequency electric field strength is calculated through the formula, and the instrument probe is isotropic.

[0059] In order to ensure the consistency of the vibrator and the orthogonality of the three axes of the probe, a batch of vibrators must be tested, and three vibrators with similar output characteristics are selected and grouped into an omnidirectional RF probe. With an RF probe, how to calibrate it? How to ensure measurement accuracy? How to ensure the consistency of the RF probe, how to improve the efficiency of calibration work and reduce the labor intensity of calibration work? This requires studying calibration methods and designing calibration systems and devices. The solution is described as follows:

[0060] See also Figures 1 to 11 , the present invention provides a technical solution:

[0061] A radio frequency probe calibration device comprises a radio frequency electric field measuring instrument 1, a rotating tray frame 2, a clamping rotating mechanism 3, a shear wave chamber 4, a radio frequency probe 5, a high frequency signal generator 6, a power amplifier 7, a high frequency millivoltmeter 8, an attenuator 9 and a computer 10.

[0062] The radio frequency electric field measuring instrument 1 is installed on the rotating tray frame 2, and the radio frequency electric field measuring instrument 1 is connected to the radio frequency probe 5 through the probe catheter;

[0063] The probe catheter is installed on the clamping and rotating mechanism 3, and the radio frequency probe 5 is in the shear wave chamber 4. The clamping and rotating mechanism 3 drives the probe catheter to rotate, thereby driving the radio frequency probe 5 to rotate in the shear wave chamber 4;

[0064] The output end of the high frequency signal generator 6 is connected to the input end of the power amplifier 7, and the output end of the power amplifier 7 is connected to one end of the shear wave chamber 4;

[0065] The high frequency millivoltmeter 8 is connected to the attenuator 9, and the attenuator 9 is connected to the other end of the shear wave chamber 4;

[0066] The radio frequency electric field measuring instrument 1 is connected to a computer 10 .

[0067] The rotating tray frame 2 includes a chassis 20, a coupling seat 21 is installed on the chassis 20, a supporting guide rod 22 is installed on the coupling seat 1, a triangular bracket 26 is installed on the supporting guide rod 22, a locking screw sleeve 23 sleeved on the supporting guide rod 22 is installed at the connection between the cross bar of the triangular bracket 26 and the supporting guide rod 22, a sliding sleeve 25 sleeved on the supporting guide rod 22 is installed at the connection between the oblique support rod of the triangular bracket 26 and the supporting guide rod 22, a locking screw sleeve 23 is also arranged below the sliding sleeve 25, and the locking screw sleeve 23 is locked by a butterfly screw 24, a deep groove ball bearing 27 is installed at one end of the cross bar of the triangular bracket 26 away from the supporting guide rod 22, the deep groove ball bearing 27 is installed on the top of the cross bar of the triangular bracket 26 through an upper bearing support 28, and a rotating tray 29 for supporting the radio frequency electric field measuring instrument 1 is installed on the deep groove ball bearing 27. The chassis is a base with a diameter between 250mm and 300mm, so that it has sufficient anti-overturning torque capacity. The support rod is required to be perpendicular to the chassis and must not be skewed. The triangular bracket is welded with the upper bearing support, locking screw sleeve, and sliding sleeve to form a stable installation structure. The outer ring of the bearing is installed with a small gap between the bearing seat, and the rotating tray is installed with a transition fit with the inner ring of the bearing to ensure that the rotating tray can rotate lightly and flexibly. Its function is to support the radio frequency measuring instrument, and the contact surface between the rotating tray and the radio frequency measuring instrument rotates relatively statically. The sliding sleeve serves as an installation guide; the locking sleeve serves as an installation guide and locking direction positioning.

[0068] The clamping and rotating mechanism 3 includes a bottom plate 30 installed above the transverse wave chamber 4, a positioning plate 31 is welded below the bottom plate 30, a rotating disk 32 is installed above the bottom plate 30, a vertical annular scale 33 is laser-marked on the outer periphery of the rotating disk 32, a rotating support rod 34 is installed on the rotating disk 32, the lower end of the rotating support rod 34 is connected to the rotating disk 32, and the upper end is fixedly connected to the connecting plate 35, the connecting plate 35 is fixedly connected to the clamping assembly 36, the clamping assembly 36 clamps and locks the probe catheter of the radio frequency probe 5, and a silicone sheath tube 37 is also provided at the connection between the clamping assembly 36 and the probe catheter of the radio frequency probe 5, and a horizontal angle scale 38 is laser-marked on the upper surface of the rotating disk 32. The silicone sheath tube is a silicone tube with an inner diameter 1mm smaller than the outer diameter of the probe catheter and a wall thickness of 2mm, and a length 20mm longer than the clamping block, and a straight seam is cut along the axial direction, which can be conveniently put on the probe catheter. The silicone sheath tube has two functions: first, to protect the probe catheter and avoid damage to the product appearance due to clamping and abrasion; second, to provide clamping preload for the slot to prevent the catheter from axial movement. The rotating support rod is welded to the rotating disk. When welding, the verticality requirement between the rotating support rod and the upper surface of the rotating disk must be ensured. When welding the connecting plate, the coaxiality requirement between the clamping center of the clamping assembly and the bearing center must be ensured.

[0069] The rotating disk 32 is provided with a lower bearing seat 321, on which a second deep groove ball bearing 320 is installed, and the rotating disk 32 rotates around the second deep groove ball bearing 320. The circular hole on the upper surface of the rotating disk 32 is a positioning hole for the rotating support rod 34, and the size of the center hole is 1 to 2 cm larger than the diameter of the probe to be measured, so as to facilitate the entry and exit of the probe.

[0070] The clamping assembly 36 includes two clamping blocks 362, the right ends of the two clamping blocks 362 are respectively connected to two right ear plates 361, the two right ear plates 361 are connected by hinges 360, the left ends of the two clamping blocks 362 are respectively connected to the rear left ear plate 363 and the front left ear plate 364, and the locking slot 366 is connected to the front left ear plate 364 by rivets 365. The cross-sectional shape of the locking slot 366 is a right-angled trapezoid. When the catheter with the rubber sheath tube probe is placed in the clamping block, the clamping block is closed and the locking slot is pressed. During the pressing process, the probe catheter will be gradually clamped and locked. The working process is shown in FIG. Fig. 9 .

[0071] The bottom plate 30 is also provided with a bottom plate angle scale 39 that matches the vertical annular scale 33 and the horizontal angle scale 38 .

[0072] The positioning plate 31 is embedded in the square hole above the shear wave chamber 4 to play a positioning role, preventing the clamping rotation mechanism 3 from moving or rotating above the shear wave chamber 4, thereby ensuring that the tested RF probe 5 is in an effective uniform electric field area.

[0073] The power amplifier 7 and the shear wave chamber 4 as well as the attenuator 9 and the shear wave chamber 4 are connected via N-type connectors.

[0074] A radio frequency probe calibration method comprises the following specific steps:

[0075] According to the radio frequency probe calibration device of claim 1, connect various instruments and equipment, turn on the power, and preheat for 10 minutes for use;

[0076] Rotate the tray of the rotating tray rack 2 to above the binding center of the clamping rotating mechanism 3;

[0077] Adjust the height of the tray, and position the RF probe sensing test point at the center of the uniform electric field of the transverse wave chamber 4, and fix its position;

[0078] Put on the silicone sheath tube at the clamping position of the RF probe;

[0079] The aerial plug of the radio frequency probe 5 passes through the central hole of the rotating tray and is inserted into the corresponding port of the radio frequency electric field measuring instrument 1, and the radio frequency electric field measuring instrument 1 is placed on the rotating tray;

[0080] The radio frequency probe 5 is naturally drooped, installed into the clamping center of the rotating mechanism 3, and locked for testing and calibration;

[0081] The radio frequency electric field measuring instrument 1 is connected to the computer 10 communication line;

[0082] The radio frequency electric field measuring instrument 1 and the computer 10 are powered on and turned on;

[0083] Adjust the knob of the high-frequency signal generator 6 output until the high-frequency millivoltmeter displays 1000mV;

[0084] The rotating disk rotates to the 0° starting position, collects data every 0.5°, and records the angle position of the strongest output signal point. There are 6 maximum value points in the rotation of 360°. Observe the data recorded by the computer 10 and the data changes of the three axes of X, Y, and Z displayed by the radio frequency electric field measuring instrument 1, and record the angle position of the maximum extreme value point of each axis, that is, record the angle values ​​of αX, αY, and αZ, which are the calibration point positions of the X, Y, and Z axes respectively;

[0085] At the calibration point of each axis, a signal is input every 25 mV until the full scale is reached, and the computer 10 records the output signal data and the fitting data to obtain a calibration curve; the calibration points of the three axes are performed in sequence to obtain three fitting curve equations of the three axes;

[0086] The computer 10 imports the three fitting curve equations into the CPU of the radio frequency electric field measuring instrument 1;

[0087] Check its correctness and whether it meets the accuracy requirements;

[0088] After the calibration of a single instrument is completed, the calibrated RF probe is disassembled;

[0089] Proceed with the calibration of the next set of instruments in turn.

[0090] The method to check its correctness and whether it meets the accuracy requirements is to adjust the output of the high-frequency signal generator 6, and the detection points are:

[0091] Detection limit, 5% FS, 20% FS, 40% FS, 60% FS, 80% FS, 100% FS;

[0092] At each detection point, input the corresponding value, drive the RF probe to rotate through the rotating disk, rotate at any angle, observe the changes of the field strength Ex, Ey and Ez of each axis, and the comprehensive field strength E remains unchanged, that is, it is isotropic;

[0093] If the comprehensive field strength E and theoretical calculation meet the accuracy requirements, the product indicators are judged to be qualified.

[0094] Manufacturing and processing technology:

[0095] Mechanical parts processing

[0096] The parts that match the bearings in the device have a precision requirement of 7 to 8 at the parts where the parts match the bearings. The parts that match the outer ring of the bearing adopt the basic shaft system and the minimum clearance fit; the parts that match the inner ring of the bearing adopt the basic hole system and the loosest transition fit.

[0097] Welding Process

[0098] The parts to be welded in the device are all made of stainless steel 304 and are welded by argon arc welding;

[0099] There should be no bending or torsion deformation caused by welding; there are three points worth noting in device welding:

[0100] ① Positioning welding of binding components

[0101] In order to ensure that the clamping center is coaxial with the inner hole of the rotating disk, auxiliary tooling is used for positioning, and a positioning block is designed. The positioning block and the rotating disk are concentrically transitioned, the center hole of the positioning block is concentric with the outer ring mating surface, and the center hole and the probe catheter are transitionally concentrically matched. First, weld the support rod on the rotating disk, and then weld the connecting block on the support rod, and then weld the weld between the connecting block and the clamping assembly; put the catheter with the sheath tube into the clamping center and clamp it tightly, adjust the height position of the clamping assembly, insert the catheter into the center of the positioning block, and slowly weld the connection between the clamping assembly and the connecting block at points to prevent welding stress from pulling and deforming.

[0102] ② When welding the rotating pallet frame, ensure that the support rod is perpendicular to the horizontal plane and use a spirit level to calibrate it. ③ When welding the upper bearing position on the rotating pallet frame, ensure that the upper surface of the pallet is horizontal after the rotating pallet is installed and use a spirit level to calibrate it.

[0103] Technical points of radio frequency probe calibration method and calibration detection device:

[0104] Improving the performance and consistency of RF probes starts with providing an accurate and consistent standard source for the RF probes being calibrated. The volume of the shear wave chamber that provides the RF electric field is limited, and the uniform electric field area in the shear wave chamber is not large. It is necessary to ensure that the RF probe sensing point is located in the uniform electric field area in the shear wave chamber, preferably in the center of the uniform electric field area. Otherwise, the sensor will not sense the standard uniform electric field, resulting in errors. Therefore, in order to ensure that the probe sensing point is located in the center of the uniform electric field area, a clamping and positioning device for the probe is designed and manufactured.

[0105] The electric field is a vector with both magnitude and direction. When the three vibrators of the probe are placed in a uniform electric field in a shear wave chamber with a certain field strength, they are placed in different directions. Even if the three vibrators have the same performance, the output magnitudes are different. The three-axis vibrator of the RF probe must be calibrated in the direction where the vibrator feels the strongest. Therefore, it is necessary to design and manufacture a rotation angle adjustment mechanism for the calibration probe. By rotating the probe on the device, the calibration point of the three-axis vibrator of the probe is found, and the angular position of the calibration point is indicated by the dial of the rotating mechanism.

[0106] The three-axis vibrator is calibrated over the entire range in the direction with the strongest sensitivity, the data is recorded, the curve is fitted, the fitting curve equation is obtained, and the equation is imported into the radio frequency electric field measuring instrument through a computer.

[0107] Among batches of oscillators, using device testing to screen and group them, and grouping three oscillators with similar output characteristics into a group to form an RF probe, is one of the factors to improve product consistency.

[0108] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A radio frequency probe calibration method, using a radio frequency probe calibration device, the radio frequency probe calibration device comprising a radio frequency electric field measuring instrument (1), a rotating tray frame (2), a clamping rotating mechanism (3), a shear wave chamber (4), a radio frequency probe (5), a high frequency signal generator (6), a power amplifier (7), a high frequency millivoltmeter (8), an attenuator (9) and a computer (10), The radio frequency electric field measuring instrument (1) is installed on the rotating tray frame (2), and the radio frequency electric field measuring instrument (1) is connected to the radio frequency probe (5) through a probe catheter; The probe catheter is mounted on the clamping and rotating mechanism (3), the radio frequency probe (5) is in the shear wave chamber (4), and the clamping and rotating mechanism (3) drives the probe catheter to rotate, thereby driving the radio frequency probe (5) to rotate in the shear wave chamber (4); The output end of the high-frequency signal generator (6) is connected to the input end of the power amplifier (7), and the output end of the power amplifier (7) is connected to one end of the shear wave chamber (4); The high-frequency millivoltmeter (8) is connected to an attenuator (9), and the attenuator (9) is connected to the other end of the shear wave chamber (4); The radio frequency electric field measuring instrument (1) is connected to a computer (10), It is characterized in that The method comprises the following specific steps: According to the RF probe calibration device, connect all instruments and equipment, turn on the power, and preheat for 10 minutes for use; The tray of the rotating tray rack (2) is rotated to above the binding center of the clamping rotating mechanism (3); Adjust the height of the tray so that the RF probe sensing test point is located at the center of the uniform electric field of the shear wave chamber (4) and its position is fixed; Put on the silicone sheath tube at the clamping position of the RF probe; The aerial plug of the radio frequency probe (5) passes through the central hole of the rotating tray and is inserted into the corresponding port of the radio frequency electric field measuring instrument (1), and the radio frequency electric field measuring instrument (1) is placed on the rotating tray; The radio frequency probe (5) is naturally drooped, installed into the clamping center of the clamping rotating mechanism (3), and locked to wait for testing and calibration; The radio frequency electric field measuring instrument (1) is connected to a computer (10) through a communication line; The radio frequency electric field measuring instrument (1) and the computer (10) are powered on and turned on; Adjust the knob of the high-frequency signal generator (6) until the high-frequency millivoltmeter displays 1000mV; The rotating disk is rotated to the 0° starting position, and a data is collected every 0.5°, and the angle position of the strongest output signal point is recorded. There are 6 maximum value points in the rotation of 360°. The data recorded by the computer (10) and the data changes of the three axes of X, Y, and Z displayed by the radio frequency electric field measuring instrument (1) are observed, and the angle position of the maximum extreme point of each axis is recorded, that is, the angle values ​​of αX, αY, and αZ are recorded, which are the calibration point positions of the X, Y, and Z axes respectively; At the calibration point position of each axis, a signal is input every 25 mV until the full scale is reached, and the computer (10) records the output signal data and the fitting data to obtain a calibration curve; the calibration points of the three axes are respectively performed in sequence to obtain three fitting curve equations of the three axes; The computer (10) imports the three fitting curve equations into the CPU of the radio frequency electric field measuring instrument (1); Check its correctness and whether it meets the accuracy requirements; After the calibration of a single instrument is completed, the calibrated RF probe is disassembled; Then calibrate the next set of instruments in turn; The method for checking its correctness and whether it meets the accuracy requirements is to adjust the output of the high-frequency signal generator (6) and the detection points are: Detection limit, 5% FS, 20% FS, 40% FS, 60% FS, 80% FS, 100% FS; At each detection point, input the corresponding value, drive the RF probe to rotate through the rotating disk, rotate at any angle, observe the changes of the field strength Ex, Ey and Ez of each axis, and the comprehensive field strength E remains unchanged, that is, it is isotropic; If the comprehensive field strength E and theoretical calculation meet the accuracy requirements, the product indicators are judged to be qualified.

2. A radio frequency probe calibration method according to claim 1, characterized in that: The rotating tray frame (2) comprises a chassis (20), a coupling seat (21) is mounted on the chassis (20), a supporting guide rod (22) is mounted on the coupling seat (21), a triangular bracket (26) is mounted on the supporting guide rod (22), a locking screw sleeve (23) sleeved on the supporting guide rod (22) is mounted at the connection between the cross bar of the triangular bracket (26) and the supporting guide rod (22), and a sliding sleeve sleeved on the supporting guide rod (22) is mounted at the connection between the oblique supporting rod of the triangular bracket (26) and the supporting guide rod (22). The sliding sleeve (25) is provided with a locking screw sleeve (23) below the sliding sleeve (25), and the locking screw sleeve (23) is locked by a butterfly screw (24). A deep groove ball bearing (27) is installed at one end of the cross bar of the triangular bracket (26) away from the supporting guide rod (22), and the deep groove ball bearing (27) is installed on the top of the cross bar of the triangular bracket (26) through an upper bearing support (28). A rotating tray (29) for supporting the radio frequency electric field measuring instrument (1) is installed on the deep groove ball bearing (27).

3. A radio frequency probe calibration method according to claim 1, characterized in that: The clamping and rotating mechanism (3) comprises a base plate (30) installed above the transverse wave chamber (4), a positioning plate (31) is welded below the base plate (30), a rotating disk (32) is installed above the base plate (30), a vertical annular scale (33) is marked on the outer periphery of the rotating disk (32) by laser, a rotating support rod (34) is installed on the rotating disk (32), the lower end of the rotating support rod (34) is connected to the rotating disk (32), and the upper end is fixedly connected to the connecting plate (35), the connecting plate (35) is fixedly connected to the clamping assembly (36), the clamping assembly (36) clamps and locks the probe catheter of the radio frequency probe (5), a silicone sheath tube (37) is also provided at the connection between the clamping assembly (36) and the probe catheter of the radio frequency probe (5), and a horizontal angle dial (38) is marked on the upper surface of the rotating disk (32) by laser.

4. A radio frequency probe calibration method according to claim 3, characterized in that: A lower bearing position (321) is installed in the rotating disk (32), a second deep groove ball bearing (320) is installed on the lower bearing position (321), and the rotating disk (32) rotates around the second deep groove ball bearing (320).

5. A radio frequency probe calibration method according to claim 3, characterized in that: The clasping assembly (36) comprises two clasping blocks (362), the right ends of the two clasping blocks (362) are respectively connected to two right ear plates (361), the two right ear plates (361) are connected via hinges (360), the left ends of the two clasping blocks (362) are respectively connected to a rear left ear plate (363) and a front left ear plate (364), and a locking slot (366) is connected to the front left ear plate (364) via a rivet (365).

6. A radio frequency probe calibration method according to claim 3, characterized in that: The bottom plate (30) is also provided with a bottom plate angle scale (39) which matches the vertical annular scale (33) and the horizontal angle scale (38).

7. A radio frequency probe calibration method according to claim 3, characterized in that: The positioning plate (31) is embedded in the square hole above the shear wave chamber (4) to play a positioning role, preventing the clamping rotation mechanism (3) from moving or rotating above the shear wave chamber (4), thereby ensuring that the radio frequency probe (5) being tested is in an effective uniform electric field area.

8. A radio frequency probe calibration method according to claim 1, characterized in that: The power amplifier (7) and the shear wave chamber (4) as well as the attenuator (9) and the shear wave chamber (4) are all connected via N-type connectors.

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