CN111123187A - Magneto-resistive chip calibration test system and method based on double ridge waveguides - Google Patents
Magneto-resistive chip calibration test system and method based on double ridge waveguides Download PDFInfo
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- CN111123187A CN111123187A CN202010072007.XA CN202010072007A CN111123187A CN 111123187 A CN111123187 A CN 111123187A CN 202010072007 A CN202010072007 A CN 202010072007A CN 111123187 A CN111123187 A CN 111123187A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/005—Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/0023—Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration
- G01R33/0035—Calibration of single magnetic sensors, e.g. integrated calibration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
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- Condensed Matter Physics & Semiconductors (AREA)
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Abstract
The invention belongs to the technical field of calibration test, and particularly relates to a magneto-resistive chip calibration test system and method based on double-ridge waveguide. The invention applies the excitation signal through the radio frequency signal source, can generate an electromagnetic field in the double-ridge waveguide, is suitable for the calibration of the tunnel magneto-resistance chip in a wide frequency band range, and can keep the field intensity uniform in a certain range. The method is used for the calibration test of the magnetic resistance chip.
Description
Technical Field
The invention belongs to the technical field of calibration test, and particularly relates to a magneto-resistive chip calibration test system and method based on double ridge waveguides.
Background
The magnetic sensor based on the tunnel magnetoresistance effect has the advantages of high sensitivity, low power consumption and the like, has irreplaceable advantages in the fields of industrial automation, test measurement, electronic industry and the like, can sense the change of physical quantity related to magnetic phenomena, and converts the physical quantity into an electric signal for output, has important significance in accurately calibrating the magnetoresistance sensor in consideration of the special working environment of the magnetoresistance sensor, and currently, a microwave darkroom or a GTEM (gas to liquid) chamber is mostly adopted for testing and calibrating the magnetic sensor.
Disclosure of Invention
Aiming at the technical problems of large volume and high price of the test equipment, the invention provides a double-ridge waveguide-based magnetoresistive chip calibration test system and method with low cost, wide coverage frequency band range and accurate precision.
In order to solve the technical problems, the invention adopts the technical scheme that:
the utility model provides a magneto resistive chip marks test system based on double ridge waveguide, includes magneto resistive chip field intensity detecting system, strong electromagnetic radiation produces the device, magneto resistive chip field intensity detecting system includes magnetic resistance probe detection module, power module, oscilloscope, strong electromagnetic radiation produces the device and includes radio frequency signal source, ripples with converter, double ridge waveguide, the both ends of double ridge waveguide are connected with ripples with the converter respectively, magnetic resistance probe detection module sets up in the inside of double ridge waveguide, radio frequency signal source passes through ripples with the converter and is connected with double ridge waveguide, magnetic resistance probe detection module passes through the wire and is connected with power module, oscilloscope respectively.
The wave-sharing converter comprises an upper converter ridge and a lower converter ridge, the double-ridge waveguide comprises an upper waveguide ridge and a lower waveguide ridge, and the upper converter ridge and the lower converter ridge are fixedly connected with the upper waveguide ridge and the lower waveguide ridge respectively.
The lower ridge of the converter is stepped.
The magnetic resistance probe detection module is arranged between the upper waveguide ridge and the lower waveguide ridge and comprises a fixing device and a tunnel magnetic resistance probe, the tunnel magnetic resistance probe is fixed at the geometric center between the upper waveguide ridge and the lower waveguide ridge through the fixing device and is connected with an oscilloscope through an electromagnetic shielding wire, and a metal mesh woven layer wraps the outside of the electromagnetic shielding wire.
The fixing device adopts low-density polyethylene grease which is filled between the upper ridge and the lower ridge of the waveguide.
The wave-to-converter is provided with a pin fixing hole, and the radio frequency signal source is fixedly connected with the wave-to-converter through the pin fixing hole.
A magneto-resistive chip calibration test method based on double ridge waveguides comprises the following steps:
s1, connecting a testing device, fixing the tunnel magnetoresistive chip on the central axis of the double-ridge waveguide, adjusting the parameters of a radio frequency signal source, and generating a uniform constant electromagnetic field inside the double-ridge waveguide;
s2, using a strong electric field environment required by the radiation test of the double-ridge waveguide, obtaining the field intensity through modeling simulation and theoretical calculation, and controlling the radiation field intensity value and the radiation frequency of the electric field in the double-ridge waveguide by adjusting the amplitude and the frequency range of an output signal of a radio frequency signal source;
s3, starting when the frequency of the radio frequency signal source is 10KHz, adjusting the signal amplitude from 0dBm, and gradually increasing until the output of the tunnel magnetoresistive probe does not linearly change any more;
s4, scanning within the test frequency range, keeping the electric field reaching the requirement of a limit value, and recording the voltage value output by the tunnel magnetoresistive probe through an oscilloscope; when a linear scanning mode is adopted, the probe resides for at least 5s at each frequency to ensure the stable work of the tunnel magnetoresistive probe;
s5, if the output of the tunnel magnetoresistive probe starts to attenuate, keeping the frequency unchanged, reducing the amplitude of the radiation signal, continuing to test and record output records until the working frequency range and field intensity range of all the magnetoresistive probes are covered;
and S6, finally, obtaining the relation between the output of the tunnel magnetoresistive probe and the radiation intensity and the radiation frequency of the electromagnetic radiation environment.
Compared with the prior art, the invention has the following beneficial effects:
the invention can completely cover the working range of the tunnel magneto-resistance chip, the calibration work is easy to operate, the invention applies the excitation signal through the radio frequency signal source, can generate the electromagnetic field in the double-ridge waveguide, is suitable for the calibration of the tunnel magneto-resistance chip in the wide frequency band range, and the field intensity can be kept uniform in a certain range, which is convenient for the theoretical simulation of delay frequency points and the calculation of the field intensity, and the device can completely replace expensive equipment such as a microwave darkroom and the like. The calibration of the tunnel magnetoresistive chip can be realized more easily, and the popularization and the use of the tunnel magnetoresistive sensor are facilitated.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a side view of a double-ridged waveguide cavity and a chip under test according to the present invention;
FIG. 3 is a schematic diagram of the distribution of the field strength in the cavity of the double-ridge waveguide of the present invention;
FIG. 4 is a schematic diagram of the horizontal cross-sectional field intensity distribution within a double-ridge waveguide cavity according to the present invention;
FIG. 5 is a schematic diagram of the distribution of the vertical cross-section field intensity within a double-ridge waveguide cavity according to the present invention;
wherein: the device comprises a magnetoresistive probe detection module 1, a power module 2, an oscilloscope 3, a radio frequency signal source 4, a wave-sharing converter 5, a double-ridge waveguide 6, a fixing device 11, a tunnel magnetoresistive probe 12, a converter upper ridge 51, a converter lower ridge 52, a pin fixing hole 53, a waveguide upper ridge 61 and a waveguide lower ridge 62.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A magneto-resistive chip calibration test system based on double-ridge waveguide is disclosed, as shown in figure 1, and comprises a magneto-resistive chip field intensity detection system and a strong electromagnetic radiation generating device, wherein the magneto-resistive chip field intensity detection system comprises a magneto-resistive probe detection module 1, a power supply module 2 and an oscilloscope 3, the strong electromagnetic radiation generating device comprises a radio frequency signal source 4, a wave synchronization converter 5 and a double-ridge waveguide 6, two ends of the double-ridge waveguide 6 are respectively connected with the wave synchronization converter 5, the magneto-resistive probe detection module 1 is arranged in the double-ridge waveguide 6, the radio frequency signal source 4 is connected with the double-ridge waveguide 6 through the wave synchronization converter 5 to provide excitation signals for the cavity of the double-ridge waveguide 6, so that an electromagnetic field with uniform distribution is generated in the cavity of the double-ridge waveguide 6, the magneto-resistive probe detection module 1 is respectively connected with the power supply module 2 and the oscilloscope 3 through wires, and the power supply is supplied to the magneto-resistive probe detection, a stable electromagnetic radiation environment is built in the double-ridge waveguide 6 through the radio frequency signal source 1, the wave homoconverter 5 and the double-ridge waveguide 6.
Further, as shown in fig. 2, the waveguide-to-waveguide converter 5 includes an upper converter ridge 51 and a lower converter ridge 52, the double-ridge waveguide 6 includes an upper waveguide ridge 61 and a lower waveguide ridge 62, and the upper converter ridge 51 and the lower converter ridge 52 are fixedly connected to the upper waveguide ridge 61 and the lower waveguide ridge 62, respectively.
Further, it is preferable that the lower ridge 52 of the converter is stepped, which is advantageous for improving the transmission efficiency of the signal.
Further, the magnetic resistance probe detection module 1 is arranged between the waveguide upper ridge 61 and the waveguide lower ridge 62, the magnetic resistance probe detection module 1 comprises a fixing device 11 and a tunnel magnetic resistance probe 12, the tunnel magnetic resistance probe 12 is fixed at the geometric center between the waveguide upper ridge 61 and the waveguide lower ridge 62 through the fixing device 11, the tunnel magnetic resistance probe 12 is connected with the oscilloscope 3 through an electromagnetic shielding wire, and a metal mesh braid layer wraps the electromagnetic shielding wire.
Further, it is preferable that the fixing device 11 is made of low density polyethylene resin, and the low density polyethylene resin is filled between the waveguide upper ridge 61 and the waveguide lower ridge 62.
Further, a pin fixing hole 53 is formed in the diplexer 5, and the radio frequency signal source 4 is fixedly connected with the diplexer 5 through the pin fixing hole 53.
A magneto-resistive chip calibration test method based on double ridge waveguides comprises the following steps:
s1, connecting a testing device, fixing the tunnel magnetoresistive chip on the central axis of the double-ridge waveguide, adjusting the parameters of a radio frequency signal source, and generating a uniform constant electromagnetic field inside the double-ridge waveguide;
s2, using a strong electric field environment required by the radiation test of the double-ridge waveguide, obtaining the field intensity through modeling simulation and theoretical calculation, and controlling the radiation field intensity value and the radiation frequency of the electric field in the double-ridge waveguide by adjusting the amplitude and the frequency range of an output signal of a radio frequency signal source;
s3, starting when the frequency of the radio frequency signal source is 10KHz, adjusting the signal amplitude from 0dBm, and gradually increasing until the output of the tunnel magnetoresistive probe does not linearly change any more;
s4, scanning within the test frequency range, keeping the electric field reaching the requirement of a limit value, and recording the voltage value output by the tunnel magnetoresistive probe through an oscilloscope; when a linear scanning mode is adopted, the probe resides for at least 5s at each frequency to ensure the stable work of the tunnel magnetoresistive probe;
s5, if the output of the tunnel magnetoresistive probe starts to attenuate, keeping the frequency unchanged, reducing the amplitude of the radiation signal, continuing to test and record output records until the working frequency range and field intensity range of all the magnetoresistive probes are covered;
and S6, finally, obtaining the relation between the output of the tunnel magnetoresistive probe and the radiation intensity and the radiation frequency of the electromagnetic radiation environment.
The calibration by the same type of method belongs to the protection scope of the invention.
Although only the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art, and all changes are encompassed in the scope of the present invention.
Claims (7)
1. The utility model provides a magnetic resistance chip marks test system based on two ridge waveguides which characterized in that: the device comprises a magnetic resistance chip field intensity detection system and a strong electromagnetic radiation generation device, wherein the magnetic resistance chip field intensity detection system comprises a magnetic resistance probe detection module (1), a power module (2) and an oscilloscope (3), the strong electromagnetic radiation generation device comprises a radio frequency signal source (4), a wave sharing converter (5) and a double-ridge waveguide (6), the two ends of the double-ridge waveguide (6) are respectively connected with the wave sharing converter (5), the magnetic resistance probe detection module (1) is arranged inside the double-ridge waveguide (6), the radio frequency signal source (4) is connected with the double-ridge waveguide (6) through the wave sharing converter (5), and the magnetic resistance probe detection module (1) is respectively connected with the power module (2) and the oscilloscope (3) through wires.
2. The magneto-resistive chip calibration test system based on the double-ridge waveguide as claimed in claim 1, wherein: the wave-mixing converter (5) comprises an upper converter ridge (51) and a lower converter ridge (52), the double-ridge waveguide (6) comprises an upper waveguide ridge (61) and a lower waveguide ridge (62), and the upper converter ridge (51) and the lower converter ridge (52) are fixedly connected with the upper waveguide ridge (61) and the lower waveguide ridge (62) respectively.
3. The magneto-resistive chip calibration test system based on the double-ridge waveguide as claimed in claim 2, wherein: the converter lower ridge (52) is stepped.
4. The magneto-resistive chip calibration test system based on the double-ridge waveguide as claimed in claim 1, wherein: the magnetic resistance probe detection module (1) is arranged between an upper waveguide ridge (61) and a lower waveguide ridge (62), the magnetic resistance probe detection module (1) comprises a fixing device (11) and a tunnel magnetic resistance probe (12), the tunnel magnetic resistance probe (12) is fixed at the geometric center between the upper waveguide ridge (61) and the lower waveguide ridge (62) through the fixing device (11), the tunnel magnetic resistance probe (12) is connected with an oscilloscope (3) through an electromagnetic shielding wire, and a metal mesh braid is wrapped outside the electromagnetic shielding wire.
5. The magneto-resistive chip calibration test system based on the double-ridge waveguide as claimed in claim 4, wherein: the fixing device (11) adopts low-density polyethylene grease which is filled between the waveguide upper ridge (61) and the waveguide lower ridge (62).
6. The magneto-resistive chip calibration test system based on the double-ridge waveguide as claimed in claim 1, wherein: the wave-to-wave converter (5) is provided with a pin fixing hole (53), and the radio frequency signal source (4) is fixedly connected with the wave-to-wave converter (5) through the pin fixing hole (53).
7. A magneto-resistive chip calibration test method based on double ridge waveguides is characterized in that: comprises the following steps:
s1, connecting a testing device, fixing the tunnel magnetoresistive chip on the central axis of the double-ridge waveguide, adjusting the parameters of a radio frequency signal source, and generating a uniform constant electromagnetic field inside the double-ridge waveguide;
s2, using a strong electric field environment required by the radiation test of the double-ridge waveguide, obtaining the field intensity through modeling simulation and theoretical calculation, and controlling the radiation field intensity value and the radiation frequency of the electric field in the double-ridge waveguide by adjusting the amplitude and the frequency range of an output signal of a radio frequency signal source;
s3, starting when the frequency of the radio frequency signal source is 10KHz, adjusting the signal amplitude from 0dBm, and gradually increasing until the output of the tunnel magnetoresistive probe does not linearly change any more;
s4, scanning within the test frequency range, keeping the electric field reaching the requirement of a limit value, and recording the voltage value output by the tunnel magnetoresistive probe through an oscilloscope; when a linear scanning mode is adopted, the probe resides for at least 5s at each frequency to ensure the stable work of the tunnel magnetoresistive probe;
s5, if the output of the tunnel magnetoresistive probe starts to attenuate, keeping the frequency unchanged, reducing the amplitude of the radiation signal, continuing to test and record output records until the working frequency range and field intensity range of all the magnetoresistive probes are covered;
and S6, finally, obtaining the relation between the output of the tunnel magnetoresistive probe and the radiation intensity and the radiation frequency of the electromagnetic radiation environment.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113125858A (en) * | 2021-04-20 | 2021-07-16 | 电子科技大学 | Single fiber dielectric constant testing device and method with double-ridge structure |
| CN114034950A (en) * | 2021-10-29 | 2022-02-11 | 西安空间无线电技术研究所 | System and method for testing electromagnetic leakage degree of aerospace passive product based on reverberation chamber |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007218656A (en) * | 2006-02-15 | 2007-08-30 | Fujitsu Ltd | Device and method for testing magnetic head |
| CN103219574A (en) * | 2012-01-19 | 2013-07-24 | 中国电子科技集团公司第十研究所 | Millimeter wave ultra-wideband spatial power combining network |
| CN203596404U (en) * | 2013-12-18 | 2014-05-14 | 中国电子科技集团公司第五十四研究所 | Ku frequency band space power synthesizer |
| JP2015062031A (en) * | 2009-08-17 | 2015-04-02 | ヘッドウェイテクノロジーズ インコーポレイテッド | Secular change correction device for magnetoresistance effect sensor |
| CN105977584A (en) * | 2016-06-06 | 2016-09-28 | 中国船舶重工集团公司第七〇九研究所 | Double-ridge loading E surface insert waveguide filter and generalized scattering matrix calculation method |
| CN206480744U (en) * | 2017-02-09 | 2017-09-08 | 南京广顺电子技术研究所 | Double ridged waveguide coaxial converter |
| CN109148243A (en) * | 2018-08-21 | 2019-01-04 | 电子科技大学 | Wideband high-power delivery of energy structure suitable for helix TWT |
| CN109342985A (en) * | 2018-11-16 | 2019-02-15 | 南方电网科学研究院有限责任公司 | A kind of magnetoresistive chip calibration correction system and method |
| CN110261684A (en) * | 2019-05-07 | 2019-09-20 | 电子科技大学 | A kind of double ridged waveguide method liquid crystal dielectric test device |
-
2020
- 2020-01-21 CN CN202010072007.XA patent/CN111123187B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007218656A (en) * | 2006-02-15 | 2007-08-30 | Fujitsu Ltd | Device and method for testing magnetic head |
| JP2015062031A (en) * | 2009-08-17 | 2015-04-02 | ヘッドウェイテクノロジーズ インコーポレイテッド | Secular change correction device for magnetoresistance effect sensor |
| CN103219574A (en) * | 2012-01-19 | 2013-07-24 | 中国电子科技集团公司第十研究所 | Millimeter wave ultra-wideband spatial power combining network |
| CN203596404U (en) * | 2013-12-18 | 2014-05-14 | 中国电子科技集团公司第五十四研究所 | Ku frequency band space power synthesizer |
| CN105977584A (en) * | 2016-06-06 | 2016-09-28 | 中国船舶重工集团公司第七〇九研究所 | Double-ridge loading E surface insert waveguide filter and generalized scattering matrix calculation method |
| CN206480744U (en) * | 2017-02-09 | 2017-09-08 | 南京广顺电子技术研究所 | Double ridged waveguide coaxial converter |
| CN109148243A (en) * | 2018-08-21 | 2019-01-04 | 电子科技大学 | Wideband high-power delivery of energy structure suitable for helix TWT |
| CN109342985A (en) * | 2018-11-16 | 2019-02-15 | 南方电网科学研究院有限责任公司 | A kind of magnetoresistive chip calibration correction system and method |
| CN110261684A (en) * | 2019-05-07 | 2019-09-20 | 电子科技大学 | A kind of double ridged waveguide method liquid crystal dielectric test device |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113125858A (en) * | 2021-04-20 | 2021-07-16 | 电子科技大学 | Single fiber dielectric constant testing device and method with double-ridge structure |
| CN113125858B (en) * | 2021-04-20 | 2022-03-08 | 电子科技大学 | Single fiber dielectric constant testing device and method with double-ridge structure |
| CN114034950A (en) * | 2021-10-29 | 2022-02-11 | 西安空间无线电技术研究所 | System and method for testing electromagnetic leakage degree of aerospace passive product based on reverberation chamber |
| CN114034950B (en) * | 2021-10-29 | 2024-05-14 | 西安空间无线电技术研究所 | System and method for testing electromagnetic leakage degree of spaceflight passive product based on reverberation room |
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