EP0941482A2 - Device for coupling an rf-squid to a super conducting tank circuit - Google Patents

Device for coupling an rf-squid to a super conducting tank circuit

Info

Publication number
EP0941482A2
EP0941482A2 EP19970951807 EP97951807A EP0941482A2 EP 0941482 A2 EP0941482 A2 EP 0941482A2 EP 19970951807 EP19970951807 EP 19970951807 EP 97951807 A EP97951807 A EP 97951807A EP 0941482 A2 EP0941482 A2 EP 0941482A2
Authority
EP
Grant status
Application
Patent type
Prior art keywords
squid
characterized
rf
arrangement according
tank circuit
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.)
Withdrawn
Application number
EP19970951807
Other languages
German (de)
French (fr)
Inventor
Marko Banzet
Jürgen Schubert
Huai-Ren Yi
Willi Zander
Yi Zhang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Forschungszentrum Julich GmbH
Original Assignee
Forschungszentrum Julich GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/02Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/035Measuring direction or magnitude of magnetic fields or magnetic flux using superconductive devices
    • G01R33/0354SQUIDS
    • G01R33/0358SQUIDS coupling the flux to the SQUID
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00Superconductor technology: apparatus, material, process
    • Y10S505/825Apparatus per se, device per se, or process of making or operating same
    • Y10S505/842Measuring and testing
    • Y10S505/843Electrical
    • Y10S505/845Magnetometer
    • Y10S505/846Magnetometer using superconductive quantum interference device, i.e. squid

Abstract

Device for coupling an rf-SQUID to a super conducting tank circuit and a base plate, in which the tank circuit and the rf-SQUID form a coplanar structure, and the tank circuit has a slit. The base plate (10) is configured as an outer loop (10a) which is coplanar to the rf-SQUID (2) and to the tank circuit (1), and has a slit (11). The tank circuit (1) encircles an inner loop (1a), in which the slit (4) is embodied. The orientation of the slits (4; 11) of the inner loop (1a) and the outer loop (10a) to one another determines the resonance frequency fr.

Description

Arrangement for coupling an rf-SQUID to a superconducting oscillating tank circuit

The present invention relates to an arrangement for coupling an rf-SQUID to a superconducting oscillating tank circuit and to a base plate in which the tank circuit and the rf-SQUID form a coplanar structure and the tank circuit has a slot.

Various proposals have been pursued so far, to couple rf SQUID magnetometers to superconductive tank oscillating circuits.

One possibility is to use a λ- resonator to which an rf-SQUID is electrically coupled and the same time as a river pickup loop works. Such a SQUID magnetometer may have a tank frequency of 3 GHz.

The use of a λ resonator is problematic because it shows only a low quality of some 100th This is in view of the already reached with the λ / 2 resonators grades of several 1000 a fairly small size. In addition, also results in the fact that a hard-to-calculate parameters by the galvanic coupling, namely, the high-frequency current distribution must be taken into account to considerable problems. The Hochfrequenzstro distribution represents a not easy to be calculated or experimentally to be controlled size. The SQUID layout is therefore difficult to optimize.

Another possibility is to produce planar LC resonant circuits of YBaCuO thin films with high frequency and high quality. This LC resonant circuits are operated in a flip-chip arrangement with the rf-SQUID in washer- SQUID structure. The thereby occurring parasitical capacities between the LC circuit and the rf-SQUID reduce the quality factor of the LC resonant circuit and make the current distribution in the combined resonant LC circuit - / washer-SQUID structure complicated.

In the as yet unpublished application 196 11 900.6, the Applicant has described the aforementioned arrangement. This solves the problem of parasitic capacitances. As before, however, there is the problem that due to the facts before that the coplanar arranged rf-SQUID and tank circuit can not be arranged with the base plate in one plane and the ground plane also represents a potential source of noise, the use of an rf-SQUID may limit -Magnetometers.

The object of the present invention is therefore to provide an arrangement which eliminates during coupling an rf-SQUID magnetometer to a superconducting oscillating circuit, the above problems.

The object is achieved according to claim 1, characterized in that the base plate is designed as outer loop co-planar to the rf-SQUID and the tank circuit and comprises a slot, and that the tank circuit includes an inner loop in which the slit is formed and the orientation of the slots of the inner loop and the outer loop to each other, the resonance frequency f r is determined.

The arrangement according to the invention relates to the possibility of an advantageous optimal coupling an rf-SQUID to a tank circuit and a base plate which does not have the aforementioned disadvantages. With the fully integrated arrangement of rf-SQUID, tank circuit and the base plate and the training or orientation of the slots in the rf-SQUID and in the base plate according to claim 1, the tank frequency can be adjusted geo- metrieabhängig in a simple manner and thus provides a significant advantage z. As in building a multichannel SQUID system for medical applications. In addition, a conditional through the base plate, noise can be suppressed.

In addition, the fully integrated arrangement permits simple estimation of coupling between the rf-SQUID and the tank circuit.

According to claim 2 it is advantageous that an adjustment of the slots to each other, a change in resonant frequency caused F__ 300 <Mhz.

Another advantage according to claim 3 is that a defined superconducting short circuit between the rf-SQUID and the tank circuit is incorporated. The Resonanzfreque- unz of the resonant circuit takes namely with decreasing dimension. Above a cutoff frequency of 1 GHz but the required SQUID electronics is very complex and expensive. By the defined superconducting short-circuit the resonant frequency is significantly reduced, so that a very simple possibility is to obtain by simple geometry change discrete frequency ranges within a span of 600 MHz, and with very small dimensions still resonant frequencies to 500 MHz. These discrete frequencies are a necessary condition for the realization of a multi-channel SQUID-HTS system.

Further advantages of the present invention are obtained by the features of the claims 4 to 12th

According to claim 13 it is advantageous that a flux transformer is integrated into the arrangement in order to increase the magnetic field sensitivity of an rf-SQUID further.

A further advantage of claim 14 is that the flux transformer comprising an input coil, which is short-circuited. This takes place a decoupling of two current forms ex istieren in such an arrangement. The two current forms differ in their high and low frequencies. By decoupling disappear parasitic contributions of the high frequency current that occur at the intersections of the flux transformer. In the decoupled state flows through the crossings only low-frequency current.

According to claim 15 it is of particular advantage if the short circuit ER at a certain position of the capacitor follows.

A further advantage of claim 16 is that the field direction of the insert loop opposite to the field direction of the coupling coil is. Thus the SQUID signal is amplified in this geometry.

Embodiments of the present invention will be described in more detail below with reference to the drawings. Show it:

Figure la is a schematic view of a first geometry of a SQUID magnetometer with a base plate designed as a coplanar loop according to the first embodiment of the present invention.

Fig. Lb shows a schematic view of a second geometry of a SQUID magnetometer with a base plate designed as a coplanar loop according to the first embodiment of the present invention;

Figure lc is a schematic view of a third geometry of a SQUID magnetometer with a base plate designed as a coplanar loop according to the first embodiment of the present invention.

Figure 2 is a diagram of a test measurement with a geometry according to Figure la..; Fig. 3a shows a schematic view of a SQUID magnetometer without built-in short circuit;

Figure 3b is a schematic view of a SQUID magnetometer according to a second embodiment of the present invention incorporating a short-circuit and with a first geometry.

3c is a schematic view of a SQUID magnetometer according to a second embodiment of the present invention incorporating a short-circuit and with a second geometry.

Fig. 3d is a schematic view of a SQUID magnetometer according to a second embodiment with built-in short-circuit and with a third geometry;

4a and 4b show a schematic representation of an rf-SQUID with a planar tank circuit and a base plate.

Fig. 5 is a plate-schematic plan view of an rf-SQUID and a tank circuit without coplanar ground;

Fig. 6 is a schematic plan view of a single-layer flux transformer with a base plate designed as a coplanar loop according vorlieg- of the invention;

Fig. 7 is a schematic view of a single-layer flux transformer with a loop formed as a coplanar base plate and a multi-layer flux transformer according to the present

Invention; Figure 8 is a schematic view of a single-layer flux transformer with a loop formed as a coplanar base plate and a multi-layer flux transformer with a short circuit according to the present invention.

Fig. 9 is a schematic plan view of a SQUID gradiometer or two-hole SQUID.

In Fig. 4a and 4b are respectively a tank circuit 1 and an rf-SQUID magnetometer 2 with Planarschwingkreisen and λ / 2 or λ resonators are shown, which are coupled to a base plate 10 made of metal or superconductor material. This has the consequence that the tank circuit 1 with an integrated SQUID 2 and the base plate 10 can not be arranged in one plane. 10 In addition, the base plate is a possible source of noise that may restrict the use of an rf-SQUID magnetometer. 2 In Fig. 5, a tank circuit 1 is shown with a coplanar arranged rf-SQUID magnetometer 2 without base plate 10.

In Fig. La to lc shows an inventive arrangement in a first embodiment is schematically shown, in which the base plate 10 is formed as a coplanar arrangement in the form of an outer loop 10a. Thereby, the tank circuit 1, the SQUID 2 and the base plate can be disposed in a plane 10 degrees.

In Figure la, lb and lc have a different geometry of a SQUID magnetometer 2 is shown in each case which is present with a coplanar arrangement of an inner loop la of the tank circuit 1 and the äußerern loop 10a of the base plate 10 as a rf resonant circuit. The SQUID geometry in figure 4a, 4b is added an additional outer superconducting loop 10a. This loop 10a is provided with a slot 11 the coplanar resonant circuit. The area A in Figure la, lb, lc can be used as washer- be designed multiloop or current injection-SQUID structure. It is also possible to use this area as a flux concentrator or flux transformer to combine the coplanar resonant circuit with a washer-SQUID magnetometer in flip-chip geometry.

A major advantage of this coplanar oscillating circuits 10a is the geometry-dependent resonance frequency of the oscillating circuit. The only difference in the geometries in Figures la to lc is the orientation of the slot 11 in the outer loop to the slot 4 in the inner loop la. In Fig. La are both slots 4, 11 aligned over each other, the difference in orientation is 0 degrees or 360 degrees. The resonant frequency is at f e. = 850 MHz. 550, the resonance frequency changes to the orientation of 180 degrees (Fig. Lc), so takes on f 1 = _ MHz. At 90 degrees (Fig. Lb), the resonance frequency f _ I = 650 MHz. This results in a very simple way to achieve discrete frequency ranges within a range of 300 MHz to the geometry by simply changing. These discrete frequency sequences Squid system is a necessary condition for the realization of a multi-channel HTS.

Through the simple change in the geometry of the coplanar oscillating circuit 10a, a frequency change of the Tankfre- is achieved frequency of the rf-SQUID. 2 This is a significant advantage over the prior art especially with regard to the development of a multichannel SQUID system, for example, medical applications.

In Fig. 2 Test measurements using this layout are shown, which at a resonant frequency of the tank circuit of 850 MHz, a quality of about 5000 and a white noise of

* ~ 5 have shown Φ O / VHZ 1.85 10th

Figures 3b to 3d show the geometry of a coplanar resonant circuit according to a second embodiment of the present invention with a defined superconducting short circuit 5. In Fig. 3a of the Resonanzschwing- is circular without this short-circuit 5 shown. The frequency in Fig. 3a is f 0 = l, l GHz at a quality Q> 5000. In Fig. 3b to 3d defined superconducting shorts 5 are fitted. These shorts 5 are at 180 degrees (Fig. 3b), 90 degrees (Fig. 3c) and 360 degrees (Fig. 3d) attached. The changes of the resonant frequency in Fig. 3b to 3d the short circuits 5 with respect to the resonant frequency without short circuit is significant. In Fig. 3b, the resonant frequency is f 1 = 920 MHz, in Fig. 3c, the resonant frequency is f 2 = 803MHz and in Fig. 3d, the resonance frequency f 3 = is 620 MHz. The quality is still better than Q> 5000 for all manufactured resonant circuits. Since the quality determines the coupling between the SQUID and the resonant circuit is still not affected by the presented improve the SQUID function.

This results in the very simple Möglichhkeit to achieve discrete frequency ranges within a range of 600 Mhz to the geometry by simply changing. Even with substrate dimensions of lO lOmm β 2 can be realized by the invention, resonance frequencies up to 500 MHz.

Fig. 6 shows schematically a further embodiment of an assembly according to the invention, in which the base plate 10 is formed as a coplanar arrangement in the form of an outer loop 10a and the tank circuit 1 and the base plate are arranged in a plane 10. Within the tank circuit 1, a flux transformer having an enclosure loop 3.1 is arranged. A SQUID gradiometer 2 or two-hole SQUID (Fig. 9) is inserted such that the Josephson junction is positioned at the point of contact of the two Washerflachen. This SQUID 2 is applied in flip-chip arrangement on the flux transformer.

In Fig. 7 is inside the tank circuit 1, a

Flux transformer is provided, which comprises a multi-layer Einkop- pelspule 3.2. The multilayer coupling coil 3.2 also has a crossover. 6

Due to the fact that present in the present arrangement, a high-frequency and low-frequency current waveform and the high frequency current affects parasitically to the intersections 6 of the flux transformer and degrades at a tank frequency of about 900 MHz, the quality of the resonant circuit is at a position A (Fig. 8) provided at a con- capacitor 7 shorts decouple the two current waveforms, so that via the crossings 6 in the decoupled state flow only low-frequency currents. The shorts are normally conducting high frequency metal shorts. The second superconducting loop 10a is used for high-frequency coupling between the SQUID 2 and flux transformer. Here affects the high frequency current and ensures the coupling between the SQUID 2 and tank circuit 1. The fact that the field direction of the deposits loop 3.1, and the multi-layer coil are 3.2 to accurately set corresponds, the SQUID signal is amplified in this geometry.

Claims

claims
1. An arrangement for coupling an rf-SQUID to a superconductivity Tenden tank circuit and to a base plate in which the tank circuit and the rf-SQUID form a coplanar structure and the tank circuit has a slot, characterized in that the base plate (as an outer loop 10a) is formed coplanar to the rf-SQUID (2) and the tank circuit (1) and a slot (11), and that the tank circuit (1) an inner loop (la) comprising, in which the slot (4) formed and the orientation of the slots (4; 11) of the inner loop (la) and the outer loop (10a) zueinan- of the resonance frequency f ^ determined.
2. Arrangement according to claim 1, characterized in that an adjustment of the slots (4, 11) a change in the resonant frequency of less than or equal F__ 300 MHz effected.
3. Arrangement according to claim 1 or 2, characterized in that installed between the rf-SQUID (2) and the tank circuit (1), a defined superconducting short-circuit (5).
4. An arrangement according to claim 3, characterized in that the defined superconducting short-circuit (5) between the inner loop (la) and the outer loop (10a) is installed.
5. The assembly of claim 3 or 4, characterized in that the orientation of the short circuit (5) for slot (4) of the inner loop (la), the resonance frequency f r determines.
6. An arrangement according to one of claims 3 to 5, characterized. that the incorporation of the defined superconducting short-circuit (5) of a change in the resonant frequency f._ causes of not more than 600 MHz.
7. An arrangement according to one of the preceding claims, characterized in that the rf-SQUID (2) has a SQUID with washer-SQUID structure.
8. An arrangement according to one of claims 1 to 6, characterized in that the rf-SQUID (2) has a SQUID with multiloop SQUID structure.
9. An arrangement according to one of claims 1 to 6, characterized in that the rf-SQUID (2) has a SQUID with current injection-SQUID structure.
10. An arrangement according to one of claims 1 to 6, characterized in that the rf-SQUID (2) has a SQUID with single-layer or multi-layer transformers with multiple windings.
11. An arrangement according to one of claims 1 to 6, characterized in that the rf-SQUID (2) has a SQUID with a Doppelspulen- gradiometer.
12. An arrangement according to claim 9, characterized in that the double coil gradiometer is formed with two series-connected coils in opposite directions.
having 13. An arrangement according to one of claims 1 to 6, characterized in that inside the tank circuit (1) is a flux transformer is formed of the coplanar outer loop (2), an insert loop (3.1) and a capacitor (7).
14. An arrangement according to claim 13, characterized in that a second coupling coil (3.2) with a cross-over (6) is provided, which is short-circuited.
15. An arrangement according to claim 14, characterized in that the short circuit at a position A of the capacitor (7) is carried out to decouple a high frequency current.
16. An arrangement according to one of claims 13 to 15, characterized in that the field direction of the insert loop (3.1) opposite the field direction of the coupling coil (3.2) extends.
17. The arrangement according to any one of the preceding claims, characterized gekennzeichneet that the tank circuit (1) has dimensions of less than 10 x 10 mm 2.
EP19970951807 1996-03-26 1997-11-26 Device for coupling an rf-squid to a super conducting tank circuit Withdrawn EP0941482A2 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DE29620718U 1996-11-28
DE1996220718 DE29620718U1 (en) 1996-03-26 1996-11-28 Arrangement for coupling an rf-SQUID magnetometer to a superconducting oscillating tank circuit
DE1997117801 DE19717801C2 (en) 1996-11-28 1997-04-26 Arrangement for coupling an rf-SQUID to a superconducting oscillating tank circuit
DE19717801 1997-04-26
DE1997215860 DE29715860U1 (en) 1996-11-28 1997-09-04 Arrangement for coupling an rf-SQUID to a superconducting oscillating tank circuit
DE29715860U 1997-09-04
PCT/DE1997/002760 WO1998023969A3 (en) 1996-11-28 1997-11-26 DEVICE FOR COUPLING AN rf-SQUID TO A SUPER CONDUCTING TANK CIRCUIT

Publications (1)

Publication Number Publication Date
EP0941482A2 true true EP0941482A2 (en) 1999-09-15

Family

ID=27217337

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19970951807 Withdrawn EP0941482A2 (en) 1996-03-26 1997-11-26 Device for coupling an rf-squid to a super conducting tank circuit

Country Status (4)

Country Link
US (1) US6300760B1 (en)
EP (1) EP0941482A2 (en)
JP (1) JP2001504589A (en)
WO (1) WO1998023969A3 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4820481B2 (en) * 2000-09-13 2011-11-24 エスアイアイ・ナノテクノロジー株式会社 SQUID
JP2002243817A (en) * 2001-02-21 2002-08-28 Hitachi Ltd Detection coil-integrated gradiometer and magnetic field measuring instrument
US6894584B2 (en) * 2002-08-12 2005-05-17 Isco International, Inc. Thin film resonators
WO2007008646A3 (en) 2005-07-12 2008-02-28 Massachusetts Inst Technology Wireless non-radiative energy transfer
US7825543B2 (en) 2005-07-12 2010-11-02 Massachusetts Institute Of Technology Wireless energy transfer
US8179133B1 (en) 2008-08-18 2012-05-15 Hypres, Inc. High linearity superconducting radio frequency magnetic field detector
US8362651B2 (en) 2008-10-01 2013-01-29 Massachusetts Institute Of Technology Efficient near-field wireless energy transfer using adiabatic system variations
DE102009025716A1 (en) 2009-06-20 2010-12-30 Forschungszentrum Jülich GmbH Meter, electrical resistance elements and measurement system for measuring time-varying magnetic fields or field gradients

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4003524A1 (en) * 1990-02-06 1991-08-08 Forschungszentrum Juelich Gmbh Circuit with superconducting quanta interference detectors or SQUIDs

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9823969A2 *

Also Published As

Publication number Publication date Type
JP2001504589A (en) 2001-04-03 application
WO1998023969A2 (en) 1998-06-04 application
WO1998023969A3 (en) 1998-07-23 application
US6300760B1 (en) 2001-10-09 grant

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