MICROWAVE RESONATOR MAGNETIC FIELD MEASURING DEVICE AND MAGNETIC FIELD MEASURING METHOD

Abstract

A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, with a base plate (11) having at least one supporting/bearing/clamping point (111), at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one input coupling means (161) for microwaves and at least one output coupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another. Also, a magnetic field measuring method having a magnetic field measuring device according to the invention.

Claims

1. A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, comprising: a base plate (11) with at least one support/bearing/clamping point (111); at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one coupling means (161) for microwaves and at least one decoupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another.

2. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the microwave resonator magnetic field measuring device (1) is readable without a piezo layer.

3. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the coupling (161) for microwaves and/or the decoupling (162) for microwaves is capacitive or inductive.

4. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein a tuning screw (17) and/or an adjustable reactance (171) and/or a geometry adjustment for detuning the mechanical oscillator (12+13) designed as a microwave resonator is provided in the base plate (11).

5. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the mechanical oscillator (12+13) designed as a microwave resonator is mounted: at exactly one point (111) at one of the ends or in the middle or at exactly two points (111), the first and the second end of the mechanical oscillator (12+13) designed as a microwave resonator.

6. The microwave resonator magnetic field measuring device (1) according to e claim 1, wherein the length of the section of the cantilever (13) provided with a conductive layer is λμW/2 or λμW/4, the magnetostrictive layer being applied over the full length or only part of the length below the conductive layer.

7. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the microwave resonator magnetic field measuring device (1) is a cavity resonator.

8. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the magnetostrictive layer (12) is applied to the cantilever (13) using thin-film technology or the magnetostrictive layer (12) itself is a cantilever (13).

9. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the microwave resonator magnetic field measuring device (1) is made free of a piezo layer, this piezo layer freedom relating to the ability to couple the signals.

10. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the microwave resonator magnetic field measuring device (1) is adapted to being read out contactlessly and/or read out remotely.

11. The microwave resonator magnetic field measuring device (1) according to claim 1, wherein the mechanical oscillator (12+13) designed as is a microwave resonator and is adapted to being electrically excited via a piezo transducer element (14).

12. The magnetic field measuring method with a microwave resonator magnetic field measuring device (1) according to claim 1, the method comprising operating the microwave resonator magnetic field measuring device (1) in microwave resonance.

13. The magnetic field measuring method according to claim 12, wherein the microwave resonator magnetic field measuring device (1) is operated in double resonance, this being done in microwave resonance and in mechanical resonance, with the microwave resonator being detuned by the mechanical oscillator (12+13), which simultaneously oscillates in mechanical resonance.

14. The magnetic field measuring method according to claim 12, wherein a remote reading of the microwave resonator magnetic field measuring device (1) takes place, the oscillation of the mechanical oscillator (12+13) in the form of a microwave resonator takes place without its own energy supply by being excited by the radiation of pulsed or intensity-modulated electromagnetic radiation of high energy and a readout of its reaction/answer takes place via microwave radiation.

Description

[0076] In the following, further exemplary embodiments or forms of the invention are described with reference to the accompanying drawings in the description of the figures;

[0077] Therein:

[0078] FIG. 1 shows a schematic representation of a first exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view;

[0079] FIG. 2 shows a schematic representation of the first exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention from FIG. 1 in a section or schematic side view;

[0080] FIG. 3 shows a schematic representation of a second exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view;

[0081] FIG. 4 shows a schematic representation of a third exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0082] FIG. 5 shows a schematic representation of a fourth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0083] FIG. 6 shows a schematic illustration of a fifth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0084] FIG. 7 shows a schematic illustration of a sixth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0085] FIG. 8 shows a schematic representation of a seventh exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view;

[0086] FIG. 9 shows a schematic representation of an eighth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view;

[0087] FIG. 10 shows a schematic illustration of the eighth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0088] FIG. 11 shows a schematic illustration of a ninth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view;

[0089] FIG. 12 shows a schematic representation of the ninth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0090] FIG. 13 shows a schematic illustration of a tenth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view;

[0091] FIG. 14 shows a schematic illustration of the tenth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view;

[0092] FIG. 15 shows a schematic representation of an eleventh exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view;

[0093] FIG. 16 shows a schematic illustration of a twelfth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view;

[0094] FIG. 17 shows a schematic representation of an exemplary embodiment of an exemplary embodiment of a frequency discriminator recognition for the magnetoelectric μw resonator and

[0095] FIG. 18 shows a schematic representation of an exemplary embodiment of the magnetoelectric μw resonator system in a block diagram.

[0096] At this point it should be pointed out again that the exemplary embodiments shown here are only intended to explain the invention and not to restrict its scope of protection.

[0097] To understand the invention, reference is made to the list of reference symbols, from which the individual elements and features that are described and illustrated in the figures can be correspondingly taken.

[0098] FIG. 1 shows a schematic illustration of a first exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view.

[0099] The microwave resonator magnetic field sensor 1 comprises a base plate 11 and a cantilever 13 which is arranged on it via a cantilever support/bearing/clamping point 111 and has a magnetostrictive layer 12. The cantilever 13 with the magnetostrictive layer 12 together form a mechanical oscillator 12+13, which is mounted on one side of the base plate 11.

[0100] In this case, a coupling 161 and an output 162 for microwaves are provided in the base plate 11.

[0101] A tuning screw 17 is also provided in the base plate 11.

[0102] The base plate 11 and the mechanical oscillator 12+13 designed as a microwave resonator are at least partially designed to be electrically conductive and are connected to one another in an electrically conductive manner.

[0103] The microwave signal can, for example, be capacitively coupled in with standard SMA plug connections via the coupling 161, wherein the corresponding inner conductor can protrude beyond the surface of the base plate 11 and its protruding length influences the coupling strength.

[0104] The base plate 11 can be made of copper, for example.

[0105] In order to produce a continuous electrical connection, electrically conductive adhesives in particular can be used to fasten the mechanical oscillator 12+13 in the cantilever support/bearing/clamping point 111.

[0106] The provided tuning screw 17 is preferably positioned near the maximum electric field of the resonator, the smaller the distance between tuning screw 17 and mechanical oscillator 12+13, the lower the resonance frequency of the resonator and the higher the measured Q factor. The tuning screw 17 can be set manually to the closest distance to the mechanical oscillator 12+13, whereby the circuit must not be short-circuited.

[0107] As possible materials of the mechanical oscillator 12+13, Si cantilever oscillators can be used, which for example can be completely coated with Ta and with Au of different thicknesses.

[0108] In particular, the cantilever 13 can be completely covered with a conductive material such as gold, the thickness of which can be greater than the thickness of the conductive layer (skin effect).

[0109] At this point it should be noted that the position of the μw coupling can be freely selected.

[0110] FIG. 2 shows a schematic representation of the first exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention from FIG. 1 in a section or schematic side view.

[0111] FIG. 3 shows a schematic illustration of a second exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view.

[0112] The mechanical oscillator 12+13 is mounted on two sides on the base plate 11.

[0113] The corresponding transverse oscillation T.sub.o is also shown. The corresponding electric fields/E-field E and magnetic fields/H-field H are also shown.

[0114] A magnetoelectric resonator with a microwave strip wire is designed, as it were.

[0115] FIG. 4 shows a schematic representation of a third exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0116] The mechanical oscillator 12+13 is supported on both sides on the base plate 11. The corresponding tuning screw 17 is arranged in the middle.

[0117] The E-fields and H-fields are also shown.

[0118] FIG. 5 shows a schematic representation of a fourth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0119] Here, the mechanical oscillators 12+13 are also supported on both sides on the base plate 11. As an alternative to the tuning screw 17, an adjustable reactance 171 is arranged in the middle.

[0120] FIG. 6 shows a schematic illustration of a fifth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0121] In this case, a central mounting of the mechanical oscillator 12+13 is provided, with a capacitive coupling 161 or decoupling 162 for microwaves being provided in the outer region of the cantilever 13.

[0122] The corresponding E-fields and H-fields are shown accordingly.

[0123] FIG. 7 shows a schematic representation of a sixth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0124] Here, two mechanical oscillators 12+13 with magnetostrictive layers 12 aligned on the respective cantilever surface 13 are shown, these being spaced from one another by a cantilever spacer 131 such that they can vibrate freely and do not touch.

[0125] As a result, common-mode interference can be suppressed, since a tuning fork sensor system is practically designed.

[0126] FIG. 8 shows a schematic illustration of a seventh exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view.

[0127] This is a tuning fork resonator arrangement with a microwave ribbon line rotated by 90° in comparison with FIG. 7.

[0128] FIG. 9 illustrates a schematic representation of an eighth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view.

[0129] A first embodiment of a miniaturized microwave resonator 1 is shown here. It is a cantilever 13 mounted on one side with a magnetostrictive layer 12, which is arranged on a base plate 11 in a cantilever support/bearing/clamping point 111.

[0130] Corresponding means for coupling 161 and decoupling 162 are provided. A corresponding microwave resonator using microstrip technology 15 is also provided. One possible implementation here is in the form of a split-ring resonator.

[0131] In FIG. 10, a schematic illustration of the eighth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention is shown in a schematic side view.

[0132] FIG. 11 shows a schematic illustration of a ninth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view.

[0133] In addition, a piezo transducer 14 is provided on the cantilever 13, which is not used for reading, but only serves to excite the mechanical oscillator 12+13, which is designed as a microwave resonator, so that the cantilever 13 is set in vibration. Possible forms of embodiment for the piezo transducer 14 include, among other things, IDT electrodes and plate capacitor electrodes.

[0134] FIG. 12 shows a schematic illustration of the ninth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0135] FIG. 13 shows a schematic illustration of a tenth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a top view.

[0136] Here, a ferrite element 18 is arranged on the underside of the cantilever 13.

[0137] FIG. 14 shows a schematic illustration of the tenth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a schematic side view.

[0138] FIG. 15 shows a schematic illustration of an eleventh exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view.

[0139] Here, a contactless readout is shown, in which a readout device 19 with an antenna is correspondingly directed at the microwave resonator 1. Here, the microwave resonator 1 is designed as a modulated scattering body.

[0140] A multiplicity of microwave resonators 1 can be distinguished by different microwave resonance frequencies of individual microwave resonators 1.

[0141] FIG. 16 shows a schematic representation of a twelfth exemplary embodiment of the microwave resonator magnetic field sensor 1 according to the invention in a three-dimensional oblique view.

[0142] In addition to FIG. 15, in this example a magnetostrictive oscillator 12+13 is equipped with an additional piezo transducer 14, wherein in addition for its control a dipole for pulse-modulated microwaves f.sub.mod 22 and an envelope rectifier 23 are provided, so that via an additional antenna 21 an irradiation-in of a pulse-modulated microwave f.sub.mod is provided to excite vibrations.

[0143] FIG. 17 shows a schematic illustration of an exemplary embodiment of an exemplary embodiment of a frequency discriminator recognition for the magnetoelectric μw resonator 1. System noise sources are represented by dashed boxes. Sources of ambient noise are marked with dashed boxes.

[0144] The sensor signal 47 modulates the μw resonance of the resonator 1, indicated by the control arrow. Depending on the set μw signal frequency, the phase and amplitude of the microwave are modulated, which can be seen as sidebands in the output spectrum.

[0145] FIG. 18 shows a schematic representation of an embodiment of the magnetoelectric μw resonator system 1 in a block diagram.

[0146] For this detection scheme, the μw read-out signal is divided into a sensor 45 and a reference path 46 by a 3 dB power divider 44. A static phase shift φME is introduced with no applied signal Bs. In the reference path 46, a phase shifter 48 inserted into the signal path inserts a set phase φPS, which enables the relative phase difference ΔφFD=φME φPS to be set at the phase discriminator without an applied magnetic signal BS.

LIST OF REFERENCE SYMBOLS

[0147] 1 microwave resonator magnetic field measuring device microwave resonator magnetic field sensor, also known as μW sensor for short [0148] 11 base plate [0149] 111 cantilever support/bearing/clamping point [0150] 12 magnetostrictive layer [0151] 13 cantilever [0152] 131 cantilever spacer [0153] 14 piezo transducers [0154] 15 split-ring resonator [0155] 161 coupling [0156] 162 decoupling [0157] 17 tuning screw [0158] 171 adjustable reactance [0159] 18 ferrite [0160] 19 readout device, antenna [0161] 21 single-beam antenna [0162] 22 dipole for pulse modulated microwave f.sub.mod [0163] 23 envelope rectifiers [0164] 30 magnetic ambient noise [0165] 31 magnetic signal [0166] 32 magnetic bias [0167] 33 magnetic noise [0168] 34 magnetostriction [0169] 35 thermomechanical noise [0170] 36 mechanical coupling [0171] 37 acoustic noise [0172] 38 mechanical resonance [0173] 39 HF (RF) resonance/μw resonance [0174] 40 HF (RF) signal/μw resonance [0175] 41 noise signal processing [0176] 42 analog signal processing [0177] 43 phase noise [0178] 44 3 dB divider [0179] 45 sensor branch [0180] 46 reference branch [0181] 47 sensor signal [0182] 48 phase shifter [0183] 49 noise spectrum analyzer [0184] 50 spectrum analyzer [0185] E E field [0186] H H field [0187] f frequency [0188] T.sub.O Transverse Oscillation [0189] L.sub.O Longitudinal oscillation