CN101140318B - Syntony type radio frequency magnetic probe - Google Patents
Syntony type radio frequency magnetic probe Download PDFInfo
- Publication number
- CN101140318B CN101140318B CN2007101575928A CN200710157592A CN101140318B CN 101140318 B CN101140318 B CN 101140318B CN 2007101575928 A CN2007101575928 A CN 2007101575928A CN 200710157592 A CN200710157592 A CN 200710157592A CN 101140318 B CN101140318 B CN 101140318B
- Authority
- CN
- China
- Prior art keywords
- coil
- probe
- transformer
- resonance
- radio frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Plasma Technology (AREA)
Abstract
The present invention discloses a resonance radio frequency magnetic probe, which is characterized in that the probe utilizes a resonance transformer to increase high output voltage breath, synchronously adopts a spurious capacitive coupling between a primary coil and a secondary coil of a plane discrete Faraday shield transformer to solve problems of lower output signals and serious common mode interference of radio frequency magnetic field measuring. The resonance radio frequency magnetic probe comprises a resonance transformer. The resonance transformer is provided with a probe coil, a Faraday shield, a hollow plane primary coil and a secondary coil. In addition, the primary coil is provided with a grounded center tap. Both sides of the coil are connected with a variable capacitance in parallel. The secondary coil is connected with a variable capacitance in series. The Faraday shield structure is arranged between the primary and secondary coil of the resonance transformer, of which they are discrete. The present invention has the benefits of simple structure, lower cost and high SNR of the magnetic probe.
Description
Technical field
The invention belongs to and relate to a kind of syntony type radio frequency magnetic probe that radio-frequency (RF) magnetic field is measured that is used for.
Background technology
The magnetic probe signal is obtained by detecting coil, according to Faraday's electromagnetic induction law, and when the magnetic field at detecting coil place changes, the magnetic induction electromotive force ε that the coil two ends produce
Wherein, S
Eff=NS is the useful area of coil, and N is a coil turn, and S is that coil section is long-pending.
After adopting the known alternating magnetic field of intensity that magnetic probe is demarcated, can calculate the magnetic induction density for the treatment of measuring magnetic field by the induction electromotive force that measures.In fundamental research and technical applications, magnetic probe has measured important application, as the magnetic-field measurement of low temperature radio frequency inductive coupled plasma source [V.A.Godyak andR.B.Piejak, J.Phys.IV 8,241 (1998)], the magnetic-field measurement of high temperature controlled nuclear fusion device [N.Bretz, Rev.Sci.Instrum.68,2927 (1997), T.Edlington, R.Martin, and T.Pinfold, Rev.Sci.Instrum.72,421 (2001), M.Takechi, K Toi, and CHS groups, Rev.Sci.Instrum.70,442 (1999)], plasma fluid generator magnetic-field measurement [R.W.Boswelland F.F.Chen, IEEE Trans.Plasma Sci.25,1229 (1997), F.F.Chen andR.W.Boswell, IEEE Trans.Plasma Sci.25,1245 (1997)] etc.
A high-performance magnetism probe need satisfy following condition:
(a) signal to noise ratio (S/N ratio) height, promptly Shu Chu magnetic induction signal is big, the electrical noise that adds that surpasses far away;
(b) frequency response is fast, makes the output signal of probe can reflect quick variation, the fluctuation in magnetic field truly;
(c) spatial resolution height, promptly the probe coil size is little;
When (d) being used to measure the variation of plasma internal magnetic field, require the disturbance of article on plasma body little.
Wherein improving signal to noise ratio (S/N ratio) is a problem important and technical difficulty is high.In magnetic probe was measured, main electrical noise derived from the capacitive coupling of magnetic probe coil usually, produces the common-mode signal that is attached on the differential mode induction electromotive force.In radio-frequency range, the capacitive coupled interference is particularly serious.In addition, owing to require the magnetic probe measurement to have high spatial resolution, the size of magnetic probe coil is less, and the useful area of coil is restricted, and the magnetic induction signal is on the low side, and this has further reduced the signal to noise ratio (S/N ratio) that magnetic probe is measured.The approach that improves the magnetic probe signal to noise ratio (S/N ratio) has two kinds: a kind of is to suppress the capacitive coupled signal, and another kind is to improve the magnetic induction signal.
The common method that suppresses the capacitive coupled signal mainly contains following several:
(1) coaxial cable difference output method [M.Light and F.F.Chen, Phys.Plasmas 2,1084 (1995)].But this method often is restricted because of the oversize of coaxial cable.
(2) offset the capacitive couplings signal of two coils by the magnetic coil that adds another one Rotate 180 °, blend together magnetic induction signal [the G.G.Borg and R.C.Cross that connector (hybrid combiner) obtains twice by one again, Plasma Phys.Controlled.Fusion 29,681 (1987)].Another kind of implementation method is the signal of two coils of storage, finishes subsequent treatment [G.G.Borg and T.Jahreis, Rev.Sci.Instrum.65,449 (1994)] on computers.
(3) centre tapped transformer.The center tap ground connection of primary of transformer, and adopt two detecting coils.The capacitive of two detecting coils coupling common-mode signal produces big or small approximately equalised electric current in two branch roads of primary of transformer, but corresponding magnetic flux cancels out each other, and the common-mode signal of transmitting by magnetic coupling is suppressed effectively.But, common-mode signal still can be transferred to secondary coil [P.K.Loewenhardt, B.D.Blackwell, and Beichao Zhang in the mode of electrostatic coupling (capacitive coupling) by stray capacitance, Rev.Sci.Instrum.64,3334 (1993), Max Light, Isaac D.Sudit, Francis F.Chen, and Donald Arnush, Phys.Plasmas 2,4094 (1995)].When using core transformers, because the restriction of structure is difficult to block effectively the electrostatic coupling of common-mode signal.In addition, when using core transformers, the high core loss of radio band has also reduced the measurement signal to noise ratio (S/N ratio).
The method that improves the magnetic induction output signal is relevant with frequency.At low-frequency band, adopt the method for step-up transformer can improve induction output signal [D.C.Black and R.M.Mayo, Rev.Sci.Instrum.67, (1508) 1996] effectively.In radio-frequency range, the past usual way is to adopt amplifier to amplify magnetic induction output signal [Christian M.Franck, Olaf Grulke and ThomasKlinger, Rev.Sci.Instrum.73,3768 (2002), R.Piejak, V.Godyak, and B.Alexandrovich, Rev.Sci.Instrum.72,4002 (2001)].The problem that exists is: (1) adopts radio-frequency amplifier to increase the cost of magnetic probe system; (2), still need to improve the magnetic induction signal of amp.in even adopted radio-frequency amplifier.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of syntony type radio frequency magnetic probe that is used to measure magnetic field, adopt the resonance type transformer to improve the magnetic induction output signal, adopt plane discrete Faraday shield to suppress capacitive coupling parasitic between the former and deputy coil of transformer simultaneously, improve the signal to noise ratio (S/N ratio) of radio-frequency magnetic probe.
The technical scheme of technical solution problem of the present invention is as follows:
Syntony type radio frequency magnetic probe is made up of the resonance type transformer of probe coil, plane discrete Faraday shield.The former and deputy coil of transformer is the plane hollow coil, primary of transformer both sides parallel variable capacitor C
1, secondary coil end series variable capacitor C
2The plane Faraday shield places between the former and deputy coil of resonance transformer, adopts two separated structures.
The syntony type radio frequency magnetic probe that the present invention proposes can increase magnetic induction differential mode output signal simultaneously, suppress capacitive coupling common-mode signal, the advantage that probe has is simple in structure, cost is low and signal to noise ratio (S/N ratio) is high.
Effect of the present invention and benefit are that this syntony type radio frequency magnetic probe can increase magnetic induction differential mode output signal simultaneously, suppress capacitive coupling common-mode signal, the advantage that probe has is simple in structure, cost is low and signal to noise ratio (S/N ratio) is high.
Description of drawings
Fig. 1 is a radio-frequency magnetic probe overall schematic.
Fig. 2 a is a magnetic probe coil sides view.
Fig. 2 b is a magnetic probe coil top view.
Fig. 3 is the double coaxial line synoptic diagram.
Fig. 4 is a plane discrete Faraday shield synoptic diagram.
Radio-frequency magnetic probe output voltage waveforms when Fig. 5 a is no Faraday shield.
Radio-frequency magnetic probe output voltage waveforms when Fig. 5 b has or not Faraday shield.
Fig. 6 a is radio-frequency magnetic probe output voltage peak value V
oWith variable capacitance C
1The variation waveform.
Fig. 6 b is radio-frequency magnetic probe output voltage peak value V
oWith variable capacitance C
2The variation waveform.
V when Fig. 7 a is big M
OmaxWith variable capacitance C
2The variation waveform.
V when Fig. 7 b is little M
OmaxWith variable capacitance C
2The variation waveform.
Fig. 8 V
OmaxVariation waveform with double coaxial line length.
Among the figure: 1 magnetic probe coil; 2 double coaxial lines; 3 high-frequency joints; 4 metallic shield boxes; 5 parallel variable capacitor C
16 primary of transformer L
17 plane discrete Faraday shields; 8 transformer secondary coil L
19 series variable capacitor C
210 high-frequency joints; 11 single coaxial cables; The ground connection center tap of 12 primaries of transformer.
Embodiment
Be described in detail specific embodiments of the invention below in conjunction with technical scheme and accompanying drawing.
Radio-frequency magnetic probe one-piece construction as shown in Figure 1.Circular magnetic probe coil 1 is made (Fig. 2 a, b) by tinsel, and tinsel is taken copper wire under the indoor temperature measurement environment; Probe coil adopts tungsten filament under plasma discharge high temperature, vacuum environment, and with quartz ampoule sealing wire and double coaxial line.Magnetic probe coil 1 lead-in wire plane, place is vertical with coil plane, to improve calibration precision and space measurement resolution.The magnetic probe coil lead links to each other with double coaxial line 2, and double coaxial line 2 is levied single coaxial cable making (Fig. 3) that impedance is 50 Ω by two Gents: get two single coaxial cables that length is identical, peel off the insulation oversheath, and close with thin copper wire around tying up.
Double coaxial line 2 inserts copper shield boxes 4 by high-frequency joint 3, again with box in rotary vane type variable capacitance 5 (C
1), primary of transformer 6 (L
1) be connected.Primary of transformer 6 and secondary coil 8 (L
2) be hollow planar coil, by diameter the copper wire coiling of 0.8mm.The position of the center tap 12 of primary winding 6 is determined by zero common-mode signal: circular probe coil 1 is being cut off about the center of the symmetry that goes between, and formation only can receive capacitively coupled symmetrical antenna; Probe coil is put into radio frequency (f=13.56MHz) radiation field, in primary of transformer 6 adjusted center tap position change radio frequency output voltage sizes; When the output voltage convergence was zero, the common-mode signal that comes from probe coil was at coil L
1In approximate cancel out each other mark and dead center tap 12.
The sheet copper that discrete Faraday shield 7 is 0.5mm by two thickness is made (Fig. 4), places between primary of transformer 6 and the secondary coil 8, with the capacitive coupling of blocking-up common-mode signal.The straight slit 13 of Faraday shield is 1mm with the width of metal part 14, adopts wire cutting technology processing.Two shielded metal plates are separately fixed on the can of ground connection, and to leave width in the middle of two plates be that the finedraw of 0.5mm is to disconnect big ring swirl channel.
In transformer secondary coil 8 one sides, seal in rotary vane type variable capacitance 9 (C
2) be.Transformer secondary voltage signal is transferred to demonstration, storage apparatus through single coaxial cable 11.
Taking length is the double coaxial line 2 of 1m, and primary winding 6 is 2 circle (L
1=0.798 μ H), secondary coil 8 is 5 circle (L
2=3.282 μ H), two coils are in strong coupling state (being that coil mutual inductance M is big), variable capacitance C
2Transfer to 52.9pF and remain unchanged.Probe coil is put into radio-frequency (RF) magnetic field, keep the locus of magnetic induction density and pin needle thread loop constant, regulate the shunt capacitance C on the former limit of transformer
1, radio frequency output voltage peak-to-peak value is with capacitor C
1Variation shown in Fig. 6 a.Work as C
1Be C
1rIn the time of (390.5pF), output voltage is obtained maximal value V
Omax, i.e. transformer output presents resonance characteristics.With C
1Be fixed on C
1r(390.5pF) under the value, output voltage V
oWith series capacitance C
2Variation shown in Fig. 6 b, transformer output this moment also presents resonance characteristics.With C
2Be fixed under the different value, regulate C
1All can obtain the resonance characteristics shown in Fig. 6 a.In Fig. 6 b, the appearance of resonance effect and C
1Relevant, have only the C of working as
1Near C
1rThe time, resonance effect just exists.Under resonance state, the transformer output voltage is far above no shunt capacitance C
1, series capacitance C
2The time (C
1=0pF, C
2=0pF) value, the radio-frequency transformer (RFT) that promptly resonates can improve the probe output voltage effectively.
In Fig. 6 a, V
OmaxSize and C
2Relevant, the relation of both opinions is shown in Fig. 7 a.At low, high C
2Value is V down
OmaxObtain big value, at medium C
2Value is V down
OmaxObtain minimum value.After increasing the distance reduction mutual inductance M between the former and deputy coil, V
OmaxWith C
2Changing Pattern shown in Fig. 7 b.Under little M, V
OmaxWith C
2Variation characteristic opposite with result among Fig. 7 a, promptly at medium C
2District V
OmaxObtain maximal value.
When magnetic probe worked in radio band, double coaxial line length can influence circuit parameter.Change input end double coaxial line length, under each length, regulate C
1Obtain V
Omax, V
OmaxWith the variation of length 1 as shown in Figure 8.Under moderate-length, V
OmaxObtain minimum value.Under the condition that measuring condition allows, should adopt short input coaxial cable, to improve the radio frequency output voltage values.Input impedance is that the numerical value oscillograph of 50 Ω shows when using, during storage rf probe output voltage, the change of single coaxial cable length can not change the peak-to-peak value of output voltage to not influence of circuit parameter, only influences the phase place of output voltage.
Claims (1)
1. resonance type transformer that is used for the radio-frequency magnetic probe is characterized in that: resonance transformer primary coil end parallel variable capacitor, and secondary coil end series variable capacitor, resonance transformer is connected with probe coil (1) by double coaxial line (2); The plane Faraday shield places between the former and deputy coil of resonance transformer, adopts two discretes, every difference ground connection; The former and deputy coil of resonance transformer is hollow plane, and there is the center tap of ground connection on primary winding limit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101575928A CN101140318B (en) | 2007-10-19 | 2007-10-19 | Syntony type radio frequency magnetic probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101575928A CN101140318B (en) | 2007-10-19 | 2007-10-19 | Syntony type radio frequency magnetic probe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101140318A CN101140318A (en) | 2008-03-12 |
| CN101140318B true CN101140318B (en) | 2010-07-28 |
Family
ID=39192345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007101575928A Expired - Fee Related CN101140318B (en) | 2007-10-19 | 2007-10-19 | Syntony type radio frequency magnetic probe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101140318B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104467912B (en) * | 2013-09-23 | 2017-04-12 | 华硕电脑股份有限公司 | Radio frequency communication system and noise isolation method applied to radio frequency communication system |
| TW201513587A (en) | 2013-09-23 | 2015-04-01 | Asustek Comp Inc | Radio frequency communication system and noise isolating method using thereof |
| CN104849678B (en) * | 2015-05-22 | 2017-07-21 | 大连理工大学 | The probe of alternating magnetic field ionization meter a kind of electric discharge suitable for low pressure very high frequency(VHF) |
| CN109031166B (en) * | 2018-08-09 | 2019-12-27 | 大连理工大学 | Magnetic probe device |
| CN114833045B (en) * | 2021-02-01 | 2023-07-25 | 江苏菲沃泰纳米科技股份有限公司 | PECVD coating system and coating method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1942786A (en) * | 2004-04-30 | 2007-04-04 | 波克股份有限公司 | RF probe apparatus for nmr check weighing system |
-
2007
- 2007-10-19 CN CN2007101575928A patent/CN101140318B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1942786A (en) * | 2004-04-30 | 2007-04-04 | 波克股份有限公司 | RF probe apparatus for nmr check weighing system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101140318A (en) | 2008-03-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108110908B (en) | Asymmetric coil magnetic coupling resonance wireless power transmission method | |
| JP4490966B2 (en) | High frequency MRI coil | |
| CN101140318B (en) | Syntony type radio frequency magnetic probe | |
| CN100363747C (en) | Gas insulation combined electric device local discharge superhigh frequency detection apparatus and method | |
| CN201514849U (en) | Composite insulation compensation type electronic voltage transformer | |
| KR20140023229A (en) | On the enhancements of planar based rf sensor technology | |
| CN103887598B (en) | A kind of satellite navigation aerial | |
| CN110187395A (en) | A kind of Zero flux shallow transient electromagnetic test coil and its test method | |
| CN104267241A (en) | High-frequency current partial discharge signal acquisition sensor | |
| CN107121153A (en) | High speed current vortex sensor | |
| Zeidi et al. | Partial discharge detection with on-chip spiral inductor as a loop antenna | |
| US11324104B2 (en) | Magnetic probe device | |
| CN108808202B (en) | High-reliability strong-coupling directional coupler based on radio frequency coaxial structure | |
| CN109038859B (en) | Wireless charging system and charging device of symmetric coupling series resonance | |
| US10782320B2 (en) | Method and sensor for measuring an alternating current | |
| CN208043919U (en) | Wideband current detection probe and wideband current detecting system | |
| CN108828493A (en) | The method that elimination temperature and other phase electric fields influence optical voltage transformer precision | |
| CN213069016U (en) | Annular coil structure for magnetic core parameter measurement | |
| CN204287389U (en) | High-frequency current local discharge signal pick-up transducers | |
| CN203930030U (en) | Transient magnetic field differential transducer | |
| Kwon et al. | Three-Dimensional Multi-Transmitting Coil With High Isolation for Spatial Wireless Charging | |
| CN103116082A (en) | Server electromagnetic radiation near field detection and analysis method | |
| CN111458571A (en) | Toroidal coil for magnetic core parameter measurement | |
| US11460599B2 (en) | Shielded-loop-resonator based gradiometer probe | |
| Duan et al. | Study on Characteristics of Different Internal UHF Sensors in GIS |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100728 Termination date: 20131019 |