JP2021043008A - Magnetic permeability measurement jig, magnetic permeability measurement device, and magnetic permeability measurement method - Google Patents

Abstract

To provide a novel and useful magnetic permeability measurement jig, a magnetic permeability measurement device using the same, and a magnetic permeability measurement method.SOLUTION: According to the disclosure, a magnetic permeability measurement jig 10 comprises: a first waveguide 20 including an excitation part 22b having a signal line path 22 generating a magnetic field by excitation signal at its one end; a second waveguide 30 including a signal line path that has, at the one end, a detection part 32b inducing a detection signal by the magnetic field generated by the excitation part affecting a measurement sample 46, the detection part arranged on and opposite the excitation part with a certain distance; and dumping resistors 50a, 50b connected between a ground line path 23 of the first waveguide and a ground line path 33 of the second waveguide. A magnetic permeability measurement device and a magnetic permeability measurement method are also disclosed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for measuring the magnetic permeability of a magnetic material, and more particularly to a jig for measuring the high-frequency magnetic permeability of a single magnetic fine particle and a magnetic permeability measuring device.

In recent years, electronic devices such as mobile phones and laptop computers have become highly integrated due to demands for miniaturization and weight reduction, and electronic devices may malfunction due to the influence of electromagnetic noise generated by the built-in integrated circuit chips. The sex is high. A noise suppression sheet that absorbs and suppresses electromagnetic noise, and inductors and choke coils are used to remove noise from power supply lines and signal lines, and noise can be suppressed over a wide frequency range from low to high frequencies. Desired.

Most of the noise suppression sheets are made by mixing magnetic fine particles with a binder and curing them. For the magnetic cores of inductors and choke coils, powder magnetic cores obtained by sintering magnetic fine particles or mixing them with a binder and hardening them in order to suppress the generation of eddy currents are used. In its development, it is important to evaluate its high-frequency magnetic permeability using magnetic fine particles as a material.

Many methods have been developed so far for measuring high-frequency magnetic permeability. Typical examples include (1) a method of arranging a magnetic material on a signal line of a planar waveguide or a microstrip line and obtaining the magnetic permeability of the magnetic material from the transmission coefficient (see, for example, Non-Patent Document 1). (2) A method of arranging a magnetic material at the short-circuit end of a microstrip line and determining the magnetic permeability from the reflection coefficient (see, for example, Patent Document 1), (3) Placing it in an open side TEM cell (high frequency cavity). A method in which a magnetic material is inserted into a shielded loop coil, an excitation AC signal is injected into a TEM cell to excite the movement of magnetization, and the magnetic permeability is obtained from the back electromotive force induced in the shielded loop coil (for example,). See Patent Document 2) and the like.

Japanese Unexamined Patent Publication No. 2008-014920 Japanese Unexamined Patent Publication No. 2004-06937

Y. Chen et al., “Novel Ultra-Wide Band (10MHz-26GHz) Permeability Measurements for Magnetic Films”, IEEE Trans. Magn., 2018, vol. 54, No. 11, 6100504

However, in the method using the transmission coefficient of Non-Patent Document 1 and the method using the reflection coefficient of Patent Document 1, the back electromotive force generated by the magnetic material with respect to the input signal on the low frequency side becomes smaller, and the signal component due to the back electromotive force becomes smaller. Is difficult to separate from the input signal, resulting in a problem of reduced measurement sensitivity. With the structure of the jig in which the shielded loop coil is arranged in the TEM cell of Patent Document 2 and the magnetic material is inserted into the shielded loop coil, it is difficult to miniaturize the TEM cell, and as a result, the measurement is performed. There is a problem that it is difficult to improve the sensitivity of the coil.

An object of the present invention is to solve the above-mentioned problems, and to provide a novel and useful jig for measuring magnetic permeability, a magnetic permeability measuring device using the jig, and a measuring method.

According to one aspect of the present invention, the first waveguide and the second waveguide having an exciting portion for generating a magnetic field by an excitation signal on one end side of the signal line. The signal line has a detection unit on one end side in which the magnetic field generated in the excitation unit acts on the measurement sample to induce a detection signal, and the detection unit faces the excitation unit at a predetermined distance. Permeability including the second waveguide and the damping resistor connected between the ground line of the first waveguide and the ground line of the second waveguide. A measuring jig is provided.

According to the above aspect, the magnetic permeability measuring jig is composed of a first waveguide and a second waveguide, and the excitation unit and the detection unit, which are signal lines, can be miniaturized. Since the exciting part and the detecting part can be easily arranged close to the sample, the sensitivity of measuring the magnetic permeability can be improved. Further, the detection signal of the detection unit is a signal due to an induced electromotive force due to the movement of magnetization of the measurement sample, but a signal due to the influence of an excitation signal from the excitation unit is also added. Since the voltage of the signal due to the detection signal and the excitation signal is proportional to the frequency, the ratio is the same. Therefore, the magnetic permeability measuring jig can obtain a constant measurement sensitivity over the entire measurement frequency, and can extremely suppress a decrease in the measurement sensitivity on the low frequency side. Further, in the magnetic permeability measuring jig, since the damping resistance is connected between the ground line of the first waveguide and the ground line of the second waveguide, the circuit generated by the magnetic permeability measuring jig can be used. Resonance can be suppressed and more accurate measurement of magnetic permeability becomes possible.

According to another aspect of the present invention, the magnetic permeability measuring jig of the above aspect, the signal generating means connected to the input portion of the magnetic permeability measuring jig to generate the excitation signal, and the magnetic permeability measurement. Provided is a magnetic permeability measuring device, which is connected to an output unit of a jig and includes a signal analysis means for analyzing the detection signal and a calculation means for obtaining the magnetic permeability from the analyzed signal.

According to the above aspect, the magnetic permeability measuring device is provided with the magnetic permeability measuring jig of the above aspect, so that the measurement sensitivity is high, and as a result, the signal-to-noise ratio (S / N ratio) is good, and the magnetic permeability is good. Since the resonance of the circuit generated by the measuring jig can be suppressed, the magnetic permeability can be measured even if the sample is a minute magnetic powder alone.

According to another aspect of the present invention, the magnetic permeability is measured by using the magnetic permeability measuring device of the other aspect, in which the power of the excitation signal is set for each measurement band and the excitation signal is input and detected. A step of measuring a signal, wherein the signal generation means is controlled so as to supply the excitation signal having a power larger than that of the high frequency side on the low frequency side to the input portion of the magnetic permeability measuring jig. The above methods are provided, including.

According to the above aspect, by using the magnetic permeability measuring jig of the above aspect, the measurement sensitivity is high, the S / N ratio is good, and the resonance of the circuit generated by the magnetic permeability measuring jig can be suppressed. Therefore, it is possible to provide a measuring method capable of measuring the magnetic permeability of a minute magnetic powder alone. Further, by setting the power of the excitation signal on the low frequency side to be larger than that on the high frequency side, it is possible to increase the power of the detection signal on the low frequency side and suppress a decrease in the S / N ratio on the low frequency side.

It is a top view which shows the schematic structure of the jig for measuring magnetic permeability which concerns on one Embodiment of this invention. It is sectional drawing which shows the schematic structure of the jig for magnetic permeability measurement which concerns on one Embodiment of this invention, and is the sectional view taken along the arrow A1-A1. It is sectional drawing which shows the schematic structure of the jig for magnetic permeability measurement which concerns on one Embodiment of this invention, and is the cross-sectional view seen by arrow of B1-B1. It is an exploded perspective view of the main part of the jig for measuring magnetic permeability which concerns on one Embodiment of this invention. It is a figure for demonstrating the sample arrangement and the measuring principle of the magnetic permeability measuring jig which concerns on one Embodiment of this invention. It is a figure for demonstrating the action of the damping resistance of the jig for measuring magnetic permeability which concerns on one Embodiment of this invention. It is a figure which shows the schematic structure of the magnetic permeability measuring apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the magnetic permeability measuring method which concerns on one Embodiment of this invention. It is a figure for demonstrating the setting of the excitation signal and the characteristic of the detection signal in the magnetic permeability measurement method which concerns on one Embodiment of this invention. It is a top view which shows the schematic structure of the jig for measuring magnetic permeability which concerns on other embodiment of this invention. It is sectional drawing which shows the schematic structure of the jig for magnetic permeability measurement which concerns on another Embodiment of this invention, and is the sectional view taken along the arrow A2-A2. It is sectional drawing which shows the schematic structure of the jig for magnetic permeability measurement which concerns on other embodiment of this invention, and is the sectional view taken in the direction of arrow of B2-B2. It is a figure which shows the transmission characteristic with respect to the damping resistance of the jig for measuring magnetic permeability which concerns on one Embodiment of this invention. It is a figure which shows the frequency characteristic of the complex magnetic permeability of the Example which concerns on this invention. It is a figure which shows.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same reference numerals are given to the elements common to the drawings, and the detailed description of the elements will not be repeated.

FIG. 1 is a top view showing a schematic configuration of a magnetic permeability measuring jig according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line A1-A1, and FIG. 3 is a cross-sectional view taken along the line B1-B1. FIG. 4 is an exploded perspective view of the main part. In FIGS. 1 to 3, a part of the configuration is shown in a perspective view. Further, for convenience of explanation, some of the components are omitted. For example, in FIG. 4, screws are omitted.

With reference to FIGS. 1 to 4, in the magnetic permeability measuring jig 10, the input waveguide 20 for transmitting the excitation signal and the excitation magnetic field generated by the high-frequency excitation signal are applied to the sample in the shield case 11. It has an output waveguide 30 for transmitting a detection signal which is a back electromotive force induced by a movement in the magnetization of the sample due to the excitation magnetic field and a change in the magnetic flux. In the magnetic permeability measuring jig 10, the input waveguide 20 and the output waveguide 30 are transformer-coupled. In this embodiment, the input waveguide 20 and the output waveguide 30 have a coplanar line structure. In the magnetic permeability measuring jig 10, for convenience of explanation, the input waveguide 20 is arranged on the lower side of the paper and the output waveguide 30 is arranged on the upper side of the paper as shown in FIG. 2, but the jig 10 is turned upside down. However, it is not particularly limited.

The input waveguide 20 has a signal line 22 extending in the X direction and ground lines (ground lines) 23 on both sides of the signal line 22 extending in the X direction on the first surface 21a of the substrate 21 made of a dielectric material. The signal line 22 extends from the excitation signal input portion 22a side to the short-circuit end 22s coupled to the ground line 23. The signal line 22 is an exciting portion 22b that generates a magnetic field applied to the sample 46 by a portion of the short-circuit end 22s (a portion on the input portion 22a side from the short-circuit end 22s). The sample 46 is arranged at a position where the excitation unit 22b and the detection unit 32b face each other, for example, a position sandwiched between the excitation unit 22b and the detection unit 32b. The exciting portion 22b extends in the direction (X-axis direction) in which the excitation signal is transmitted with a predetermined width.

In the signal line 22, the signal line 40a of the coaxial cable 40 is connected to the excitation signal input unit 22a side. The coaxial cable 40 transmits an excitation signal from an excitation signal generator (shown in FIG. 7). The width of the signal line 22 is formed to be a predetermined width from the input portion 22a side of the excitation signal toward the excitation portion 22b. As an alternative example, for example, the signal line 22 may be formed widely only in a portion to which the coaxial cable 40 on the input portion 22a side is connected, and the other portion may be formed in the same width as the exciting portion 22b. It may be formed so as to be narrowed to 22b at a predetermined ratio in the length direction (X-axis direction).

The ground line 23 is provided on both sides of the signal line 22 on the input portion 22a side, and the ground line 40b covering the insulating member 40c of the coaxial cable 40 is connected to each. The ground line 23 is formed at a predetermined distance from the side portion of the signal line 22. The ground line 23 is coupled at the short-circuit end 22s of the exciting portion 22b. The ground line 23 is formed so that the width (length in the Y direction) gradually narrows toward the tip in a plan view, which reduces the capacitive coupling of the output waveguide 30 with the ground line 33. It is preferable from the viewpoint of causing.

Like the input waveguide 20, the output waveguide 30 has a signal line 32 and ground lines 33 on both sides thereof on a substrate 31 made of a dielectric material. The signal line 32 extends from the output unit 32a side of the detection signal to the short-circuit end 32s coupled to the ground line 33. The signal line 32 is a detection unit 32b that detects the magnetic flux generated by applying a magnetic field to the sample at the portion of the short-circuit end 32s (the portion on the output unit 32a side from the short-circuit end 32s). The detection unit 32b is arranged in parallel with the excitation unit 22b at a predetermined distance, and the sample 46 is arranged between the detection unit 32b and the excitation unit 22b. The detection unit 32b extends in the length direction (X-axis direction) with a predetermined width.

In the signal line 32, the signal line 43a of the coaxial cable 43 is connected to the output unit 32a side of the excitation signal. The coaxial cable 43 transmits the detection signal to the low noise amplifier or the detection signal analyzer (both are shown in FIG. 7). The width of the signal line 32 is formed to be a predetermined width from the detection unit 32b toward the output unit 32a of the detection signal. As an alternative example, for example, the signal line 32 may be formed as wide as only the portion to which the signal line 43a of the coaxial cable 43 on the output side is connected, and the other portion may be formed with the same width as the detection unit 32b. The detection unit 32b may be formed so as to be narrowed at a predetermined ratio with respect to the length direction (X-axis direction).

The ground line 33 is formed in the same manner as the ground line 23 of the input waveguide 20, and the ground line 43b of the coaxial cable 43 is connected to the ground line 33. In a plan view, the ground line 33 preferably has a small overlapping area with the ground line 23 of the input waveguide 20 from the viewpoint of reducing capacitive coupling.

The excitation unit 22b and the detection unit 32b are formed so that the opposite lengths (lengths in the X-axis direction) along the direction in which the excitation signal and the detection signal are transmitted (X-axis direction) are 10 mm or less in terms of measurement sensitivity, respectively. It is preferable that the sample 46 is formed to be 0.1 mm or more in terms of the arrangement of the sample 46 and the ease of superimposing the exciting portion 22b and the detecting portion 32b so as to face each other. Further, the length of the exciting unit 22b and the detecting unit 32b in the X-axis direction may be 10 nm or more. By manufacturing the exciting part 22b and the detecting part 32b and arranging the sample using microfabrication technology, for example, semiconductor process technology, it is possible to measure the magnetic permeability of a very small sample with a size of several nm with high sensitivity. It becomes.

The signal lines 22 and 32 and the ground lines 23 and 33 of the input waveguide 20 and the output waveguide 30 are made of a conductive material such as copper and have a thickness of, for example, 35 μm. The substrates 21 and 31 are made of, for example, a glass cloth base material epoxy resin laminated plate (glass epoxy), and have a thickness of, for example, 1.6 mm. The input waveguide 20 and the output waveguide 30 are formed so that the transmission impedance is, for example, 50Ω.

The magnetic permeability measuring jig 10 may be provided with a non-magnetic insulating layer 47 in order to separate the exciting unit 22b and the detecting unit 32b by a predetermined distance between the exciting unit 22b and the detecting unit 32b. .. The non-magnetic insulating layer 47 may have an adhesive material on the surface for fixing the sample 46 on, for example, the exciting portion 22b. As the non-magnetic insulating layer 47, for example, a polyimide tape having an adhesive can be used.

With particular reference to FIG. 3, in the magnetic permeability measuring jig 10, damping resistors 50a and 50b are electrically connected between the ground line 23 of the input waveguide 20 and the ground line 33 of the output waveguide 20. To. Specifically, electrodes 51a to 51d are formed on the second surface 31b of the substrate 31 of the output waveguide 30, one damping resistor 50a is mounted on the electrodes 51a and 51b, and the electrodes 51c and 51d The other damping resistor 50b is mounted on the.

The electrode 51a is electrically connected to the ground line 33 formed on the first surface 31a of the substrate 31 via a via 52a penetrating the substrate 31. The electrode 51b is electrically connected to the connection electrode 53a formed on the first surface 31a of the substrate 31 via a via 52b penetrating the substrate 31. The connection electrode 53a becomes conductive when the connection electrode 54a formed on the first surface 21a of the substrate 21 and the substrate 21 and the substrate 31 come into contact with each other by tightening the screw 55 to the holding member 11a. The connection electrode 54a is electrically connected to the ground line 23 by a conductive pattern formed on the first surface 21a. As a result, one damping resistor 50a is electrically connected to the ground line 23 of the input waveguide 20 and the ground line 33 of the output waveguide 20. The other damping resistor 50b is also electrically connected to the ground line 23 of the input waveguide 20 and the ground line 33 of the output waveguide 20 in the same manner.

FIG. 5 is a diagram for explaining the measurement principle of the magnetic permeability measuring jig according to the embodiment of the present invention. FIG. 5 (a) schematically shows a cross-sectional view of the exciting portion 22b and the detecting portion 32b along the Y direction as in FIG. 3, and FIG. 5 (b) shows the exciting portion of FIG. 5 (a). It is an enlarged view of 22b and the detection part 32b. In FIGS. 5A and 5B, the substrates 21, 31 and the non-magnetic insulating layer 47 are not shown for convenience of explanation.

With reference to FIG. 5A, it is assumed that the excitation signal flows from the front side to the back side of the paper surface in the excitation unit 22b. _{An excitation magnetic field H ex} is generated around the excitation portion 22b by the excitation signal. When the excitation magnetic field H _ex is applied to the sample, since the sample is a ferromagnet, a magnetic flux B _id is generated by the movement of its magnetization, an induced electromotive force is generated in the detection unit 32b, and a detection signal is generated.

With reference to FIG. 5B, the width w ₂ of the exciting portion 22b is substantially the same as the _{sample width w 1 (substantially the same (w 1} ≈ w ₂ )) in that the excitation efficiency increases. It is preferable, and substantially the same is even more preferable. _{The width w 3} of the detection unit 32b is also preferably substantially the same as the width w 1 of the sample (substantially the same (w ₁ ≈ w ₃ )) in that the detection sensitivity is increased. The widths w ₂ and w ₃ are preferably 0.1 mm or more in terms of the arrangement of the sample 46 and the ease of superimposing the exciting portion 22b and the detecting portion 32b so as to face each other. The distance between the excitation portion 22b and the detection portion 32b (center line distance) d ₁ is smaller in terms of measurement sensitivity than the width w ₃ of width w ₂ and the detection portion 32b of the excitation portion _{22b (d 1 <w 1,} w ₂ ) is preferable. Further, the widths w ₂ and w ₃ may be 10 nm or more. By manufacturing the exciting part 22b and the detecting part 32b and arranging the sample using microfabrication technology, for example, semiconductor process technology, it is possible to measure the magnetic permeability of a very small sample with a size of several nm with high sensitivity. It becomes.

The sample 46 may be arranged so as not to come into contact with the surfaces of the exciting part 22b and the detecting part 32b, or may be arranged so as to come into contact with any of the surfaces thereof. However, the exciting unit 22b and the detecting unit 32b are prevented from coming into direct contact with each other.

FIG. 6 is a diagram for explaining the action of the damping resistance of the magnetic permeability measuring jig according to the embodiment of the present invention. Referring to FIG. 6 together with FIG. 1, the magnetic permeability measuring jig 10 has a parasitic inductance L (approximately) attached to the ground lines of the coaxial cables 40 and 43, the input waveguide 20, and the output waveguide 30. The sum of the parasitic inductance L1 on the input side and the parasitic inductance L2 on the output side), the stray capacitance Cs between the coaxial cable 40 and the coaxial cable 43, and the stray capacitance Ct formed by the exciting portion 22b and the detecting portion 32b. The shield case 11 creates an LC resonant circuit. Since the damping resistor 50 (combined resistance of the damping resistors 50a and 50b) is connected between the ground line 23 of the input waveguide 20 and the ground line 33 of the output waveguide, it is connected to the LC resonance circuit. The LCR resonance circuit is formed as a whole. According to the study of the present inventor, the damping resistor 50 can suppress resonance at a relatively low frequency, for example, a resonance frequency on the order of 100 MHz to 1 GHz, and can measure the magnetic permeability more accurately. Become.

Returning to FIG. 3, the damping resistors 50a and 50b are arranged symmetrically on both sides of the exciting portion 22b and the detecting portion 32b. As a result, resonance on the high frequency side can be effectively suppressed.

The damping resistors 50a and 50b may be only one of them as long as they have the same resistance value as the combined resistance value.

FIG. 7 is a diagram showing a schematic configuration of a magnetic permeability measuring device according to an embodiment of the present invention. With reference to FIG. 7, the magnetic permeability measuring device 60 is roughly classified into a magnetic permeability measuring jig 10, a low noise amplifier 62, a signal generation analysis unit 64, a DC magnetic field generation unit 70, and a control calculation unit. Has 80 and.

The magnetic permeability measuring jig 10 is the magnetic permeability measuring jig 10 shown in FIGS. 1 to 4 according to the above embodiment, and further, the transparency of other embodiments shown in FIGS. 11 and 12 described later. Permeability measuring jig 100 may be used.

The low noise amplifier 62 is connected to the output section of the output waveguide 30 of the magnetic permeability measuring jig 10 to amplify the detection signal. As the low noise amplifier 62, a commercially available low noise amplifier can be used, and it is preferable that the low noise amplifier 62 has a constant amplification factor in the entire measurement band and the noise itself is low. In the low noise amplifier 62, the amplification factor is larger than the noise figure of the detector (not shown) of the detection signal analyzer 68, which suppresses the influence of the noise figure of the detector and improves the overall S / N ratio. Is preferable, for example, 25 dB to 30 dB. It is preferable, but not essential, to use the low noise amplifier 62 for the magnetic permeability measuring device 60.

The signal generation analysis unit 64 controls the excitation signal generator 65 that generates an excitation signal to be supplied to the input waveguide 20 of the magnetic permeability measuring jig 10, and the power and frequency of the excitation signal of the excitation signal generator 65. It has an excitation signal controller 66 and a detection signal analyzer 68 that receives and analyzes the detection signal amplified by the low noise amplifier 62. The signal generation analysis unit 64 can use, for example, a commercially available vector network analyzer (VNA).

The DC magnetic field generation unit 70 includes an electromagnet 71 and a DC magnetic field controller 72 that controls the electromagnet 71. The electromagnet 71 is controlled by the DC magnetic field controller 72 and generates a magnetic field to be applied to the sample 46 of the magnetic permeability measuring jig 10 arranged between the pair of magnetic poles. The magnitude of the magnetic field applied by the electromagnet 71 is appropriately selected according to the sample 46, and is, for example, about 2T (tesla) at the maximum. A permanent magnet may be used instead of the electromagnet 71. For example, a plurality of permanent magnets having different residual magnetic flux densities may be used in combination as necessary.

The control calculation unit 80 controls the signal generation analysis unit 64 and the DC magnetic field controller 72, and receives the frequency characteristic data of the S parameter from the detection signal analyzer 68 to calculate the complex magnetic permeability. Although not shown, the control calculation unit 80 includes a semiconductor memory for storing data, a display, a keyboard, and a mouse. The control calculation unit 80 can use, for example, a PC (personal computer).

FIG. 8 is a flowchart showing a magnetic permeability measuring method according to an embodiment of the present invention. A method for measuring the magnetic permeability will be described with reference to FIG. 8 and FIG. 7.

ここで、Ｃは透磁率測定用治具１０と試料４６に固有の補正係数であり、Ｓパラメータの下添え字「２１」は透磁率測定用治具１０の入力側から出力側の伝送Ｓパラメータであることを表し、Ｓパラメータの上添え字「０」（ｎ＝０）は試料の磁化が飽和した磁界における伝送Ｓパラメータであることを表し、Ｓパラメータの上添え字「１」（ｎ＝１）は所定の磁界における伝送Ｓパラメータであることを表す。所定の磁界は、例えば、試料が実装された環境において試料に印加される直流磁界を用いる。試料が電子基板を格納した筐体に設置するノイズ抑制シートに用いられる場合は、所定の磁界は、例えば、０（零）Ｔ（テスラ）を選択する。 The magnetic permeability μ is represented by the following formula (1).

Here, C is a correction coefficient peculiar to the magnetic permeability measuring jig 10 and the sample 46, and the subscript "21" of the S parameter is a transmission S parameter from the input side to the output side of the magnetic permeability measuring jig 10. The S-parameter superscript "0" (n = 0) indicates that the S-parameter is a transmission S-parameter in a magnetic field where the magnetization of the sample is saturated, and the S-parameter superscript "1" (n = 0). 1) indicates that it is a transmission S parameter in a predetermined magnetic field. As the predetermined magnetic field, for example, a DC magnetic field applied to the sample in the environment in which the sample is mounted is used. When the sample is used for a noise suppression sheet installed in a housing containing an electronic substrate, the predetermined magnetic field is selected, for example, 0 (zero) T (tesla).

First, in step S100, the correction coefficient C is determined. Specifically, the sample 46 is set in the magnetic permeability measuring jig 10, the sample 46 is applied to the DC magnetic field by the electromagnet 71, and an excitation signal of a predetermined frequency (low frequency) is applied to the magnetic permeability measuring jig 10. The detection signal is measured by the detection signal analyzer 68, and the transmission S parameter S ⁿ ₂₁ is measured. Several points are selected for the magnitude of the DC magnetic field within a range in which the magnetization of the sample is sufficiently saturated, and the transmission S parameter S ⁿ ₂₁ is measured _{for each magnitude of the DC magnetic field H B.} ^{Next, from the magnitude of S n} ₂₁ measured by the control calculation unit and the applied DC magnetic field H _B , the theoretical formula μ = M _S / H _B + 1 (where M _S is the saturation magnetization of the sample) is fitted. By doing so, the correction coefficient C of the above formula (1) is determined.

Next, in step S110, the DC magnetic field H _B of the electromagnet 71 is set to a predetermined magnetic field (n = 1) by the DC magnetic field controller 72, and the electromagnet 71 directs current to the sample arranged on the magnetic permeability measuring jig 10. A magnetic field H _B is applied. The magnetic permeability measuring jig 10 is arranged so that the _{DC magnetic field H B} is applied to the exciting portion 22b in parallel with the direction in which the excitation signal flows. The saturated magnetic field described later is also applied in the same direction. The DC magnetic field H _B is the case where the superscript of the S parameter is "1" in the above equation (1).

Next, in step S120, the power of the excitation signal is set for each measurement band, the excitation signal is input, and the detection signal is measured. Specifically, the entire band of the frequency for measuring the magnetic permeability is divided into a plurality of measurement bands, the power of the excitation signal is set for each measurement band, and the excitation signal is input to the magnetic permeability measuring jig 10. , Measure the detection signal as an output.

FIG. 9 is a diagram for explaining the setting of the excitation signal and the characteristics of the detection signal in the magnetic permeability measuring method according to the embodiment of the present invention. With reference to FIG. 9, the excitation signal divides the frequency for measuring magnetic permeability, for example, the entire measurement band f _{0 to} f ₄ of 1 MHz to 50 GHz into a plurality of bands, in this example, four bands FB _{1 to FB 4.} To do. For each band FB ₁ ~FB _4, it sets the power P _i of the excitation signal indicated by the solid line in FIG. 9 to P ₁ to P _4. The excitation magnetic field generated by the excitation unit 22b is applied to the sample 46 in response to the excitation signal, and the change in the magnetic flux generated by the movement of the magnetization of the sample induces the detection signal as a counter electromotive force in the detection unit 32b. The detection signal is shown by a broken line in FIG. When the power of the excitation signal is constant over the entire measurement band, the power of the detection signal becomes lower in the lower frequency band due to the characteristics. Further, since the power of Johnson noise is constant over the frequency, the lower the frequency side, the more the S / N ratio is affected. In this embodiment, the power P _i of the excitation signal is set larger the lower frequency side than the high frequency side. As a result, the power of the detection signal increases on the low frequency side, so that a detection signal having almost the same power can be obtained over the entire measurement band, so that the detection signal analyzer 68 is not saturated, that is, the detection signal analyzer 68. It is possible to suppress a decrease in the S / N ratio on the low frequency side due to Johnson noise without saturating the output beyond the input power range of the detector.

Further, the detection signal is amplified by the low noise amplifier 62, and the amplified detection signal is shown by a alternate long and short dash line in FIG. As a result, by increasing the power of the detection signal on the low frequency side, it is possible to further suppress the decrease in the S / N ratio on the low frequency side due to Johnson noise without saturating the low noise amplifier 62 and the detection signal analyzer 68. ..

Returning to FIG. 8, in step S130, it is determined whether or not the measurement of the entire measurement frequency is completed. If the measurement of the entire measurement frequency is not completed (in the case of "No"), S120 is performed until the measurement is completed. When the measurement of the entire measurement frequency is completed (in the case of “Yes”), the process proceeds to step S140.

^{Next, in step S140, the S parameter S 1} ₂₁ in a predetermined magnetic field over the entire measurement frequency is acquired from the data of the amplified detection signal of S120.

Next, in step S150, _{it is determined whether or not the DC magnetic field H B} generated by the electromagnet 71 is a magnetic field (saturated magnetic field) in which the magnetization of the sample 46 is saturated. If the DC magnetic field H _B is not a saturated magnetic field (“No”), the process proceeds to step S152, and if the DC magnetic field H _B is a saturated magnetic field (“Yes”), the process proceeds to step S160.

In step S152, the applied magnetic field H _B of the electromagnet 71 is set to the saturated magnetic field (n = 0) by the DC magnetic field controller 72. The saturated magnetic field is set to a magnetic field that saturates the magnetization of the sample and is sufficiently large to minimize the movement of magnetization with respect to the excitation magnetic field that alternates at high frequencies due to the excitation signal. The saturated magnetic field is the case where the superscript of the S parameter is “0” in the above equation (1). Next, a saturated magnetic field is applied to perform S120 and S130, and in S140, the S parameter S ⁰ ₂₁ in a predetermined magnetic field over the entire measurement frequency in the saturated magnetic field is acquired from the data of the amplified detection signal of S120.

In step S160, the magnetic permeability over the entire measurement frequency is calculated. Specifically, the control calculation unit 80 receives the S-parameters S ⁰ ₂₁ and S ¹ ₂₁ from the detection signal analyzer 68, and uses the correction coefficient C calculated in S100 to perform complex permeability according to the above equation (1). Performs an operation to obtain the magnetic coefficient. The control calculation unit 80 can store the obtained complex magnetic permeability in a memory, a hard disk drive, a cloud, or the like, display it on a display, and print it with a printer.

The above magnetic permeability measuring method may be executed by the control calculation unit 80 as a software program, or the control calculation unit 80 may be configured as hardware, whereby the control calculation unit 80 may be executed by the signal generation analysis unit 64. And the DC magnetic field generator 70 can be controlled to measure the magnetic permeability.

As a modification of the above measurement method, the detection signal may be measured in S120 with the power of the excitation signal constant over the entire measurement band.

According to the present embodiment, in the magnetic permeability measuring jig 10, the input waveguide 20 and the output waveguide 30 have a coplanar line structure, and the excitation unit 22b and the detection unit 32b, which are signal lines, are connected to each other. Since the size can be reduced and the exciting unit 22b and the detecting unit 32b can be easily arranged close to the minute magnetic powder alone, the measurement sensitivity of the magnetic permeability can be improved. The exciting unit 22b and the detecting unit 32b are terminal portions short-circuited with the ground lines 23 and 33, respectively, and the exciting unit 22b and the detecting unit 32b are arranged so as to face each other, so that the influence of the electric field can be suppressed. .. The detection signal of the detection unit 32b is a signal due to an induced electromotive force due to the movement of magnetization of the sample 46, but a signal due to the influence of an excitation signal from the excitation unit 22b is also added. Since the voltage of the signal due to the detection signal and the excitation signal is proportional to the frequency, the ratio is the same. Therefore, the magnetic permeability measuring jig 10 can obtain a constant measurement sensitivity over the entire measurement frequency. In the magnetic permeability measuring jig 10, since the damping resistors 50a and 50b are electrically connected between the ground line 23 of the input waveguide 20 and the ground line 33 of the output waveguide 20, the magnetic permeability measuring jig 10 is used. The resonance of the LC resonance circuit generated by the tool 10 can be suppressed, and more accurate measurement of magnetic permeability becomes possible. The magnetic permeability measuring jig 10 can extremely suppress a decrease in measurement sensitivity that occurs on the low frequency side in the measuring devices described in Patent Document 1 and Non-Patent Document 1.

According to the present embodiment, the magnetic permeability measuring device 60 is provided with the magnetic permeability measuring jig 10, so that the measurement sensitivity is high and the S / N ratio is good. Therefore, the magnetic permeability of a minute magnetic powder alone Can be measured. Further, the power P _i of the excitation signal by the low frequency side is set larger than the high frequency side, to increase the power of the low frequency side of the detection signal, substantially the same power of the detection signal over the entire measurement band Since it is obtained, it is possible to suppress a decrease in the S / N ratio on the low frequency side due to Johnson noise. Further, the magnetic permeability measuring jig 10 can suppress the resonance of the LC resonance circuit generated by the magnetic permeability measuring jig 10 by the damping resistors 50a and 50b, and can measure the magnetic permeability more accurately.

According to the magnetic permeability measuring method of the present embodiment, by using the magnetic permeability measuring jig 10, the measurement sensitivity is high and the S / N ratio is good, so that the magnetic permeability of a minute magnetic powder alone is measured. becomes possible, also, the power P _i of the excitation signal by the low frequency side is set larger than the high frequency side, to increase the power of the low frequency side of the detection signal, substantially equal power over the whole measurement zone Since the detection signal of is obtained, it is possible to suppress a decrease in the S / N ratio on the low frequency side. Further, the magnetic permeability measuring jig 10 can suppress the resonance of the LC resonance circuit generated by the magnetic permeability measuring jig 10 by the damping resistors 50a and 50b, and can measure the magnetic permeability more accurately.

An embodiment which is a modification of the magnetic permeability measuring jig 10 of the above-described embodiment will be described below.

10 is a top view showing a schematic configuration of a magnetic permeability measuring jig according to another embodiment of the present invention, FIG. 11 is a cross-sectional view taken along the line A2-A2, and FIG. 12 is a cross-sectional view taken along the line B2-B2. It is a figure.

With reference to FIGS. 10 to 12, in the magnetic permeability measuring jig 100, the input waveguide 120 for transmitting the excitation signal and the magnetic field generated by the excitation signal are applied to the sample 46, and the excitation magnetic field causes the sample. It has an output waveguide 130 for transmitting a detection signal which is a back electromotive force induced by a movement in magnetization and a change in magnetic flux. In this embodiment, the input waveguide 120 and the output waveguide 130 have a microstrip line structure. In the magnetic permeability measuring jig 100, the input waveguide 120 is arranged on the lower side of the paper surface and the output waveguide 130 is arranged on the upper side of the paper surface for convenience of explanation, but the jig 100 may be upside down and is not particularly limited. ..

The input waveguide 120 has a signal line 122 on a first surface 121a of a substrate 121 made of a dielectric material, and a ground line 123 on a second surface 121b and an end surface 121c on the back surface thereof. The signal line 122 extends from the side of the excitation signal input portion 122a to the short-circuit end 122s coupled with the ground line 123 formed on the end surface 121c. The signal line 122 is an exciting portion 122b that generates a magnetic field applied to the sample 46 by a portion of the short-circuit end 122s (a portion on the input portion 122a side from the short-circuit end 122s). The sample 46 is arranged at a position where the excitation unit 122b and the detection unit 132b face each other, for example, a position sandwiched between the excitation unit 122b and the detection unit 132b. The exciting portion 122b extends in the length direction (X direction) with a predetermined width.

In the signal line 122, the signal line 40a of the coaxial cable 40 is connected to the excitation signal input portion 122a side. The signal line 122 is formed in the same manner as the signal line 22 of the magnetic permeability measuring jig 10, and a detailed description thereof will be omitted. The ground line 123 is provided on the second surface 121b and the end surface 121c of the substrate 121, and the ground line 40b covering the insulating member 40c of the coaxial cable 40 is connected on the input portion 123a side. The ground line 123 is coupled to the signal line 122 by being continuous with the short-circuited end 122s of the exciting portion 122b at the portion formed on the end surface 121c. The ground line 123 may be formed on the entire second surface 121b in a plan view, or may be formed so that the width (length in the Y direction) gradually narrows toward the tip end.

The output waveguide 130 is formed in the same manner as the input waveguide 120. In the signal line 132, the portion of the short-circuit end 132s (the portion on the output unit 132a side from the short-circuit end 132s) coupled to the ground line 133 serves as a detection unit 132b for detecting the magnetic flux generated by applying a magnetic field to the sample. .. The detection unit 132b is arranged in parallel with the excitation unit 122b at a predetermined distance, and the sample 46 is arranged between the detection unit 132b and the excitation unit 122b.

The signal line 132 is formed in the same manner as the input waveguide 120, and the signal line 43a of the coaxial cable 43 is connected to the output unit 132a side of the excitation signal. The ground line 133 is formed in the same manner as the ground line 123 of the input waveguide 120, and detailed description thereof will be omitted.

The magnetic permeability measuring jig 100 may be provided with a non-magnetic insulating layer 47 in order to separate the exciting unit 122b and the detecting unit 132b by a predetermined distance between the exciting unit 122b and the detecting unit 132b. ..

With reference to FIG. 12, in the magnetic permeability measuring jig 100, damping resistors 50a and 50b are electrically connected between the ground line 123 of the input waveguide 120 and the ground line 133 of the output waveguide 120. .. Specifically, one damping resistor 50a is mounted on the ground line 133 and the electrode 151a on the second surface 131b of the substrate 131 of the output waveguide 130, and the other damping resistor 50b is mounted on the ground line 133 and the electrode 151b. Is implemented. Although the electrode 151a and the electrode 151b are formed on the second surface 131b, they are separated from the ground line 123 and are not directly electrically connected to each other.

The electrode 151a is electrically connected to the connection electrode 153a formed on the first surface 31a of the substrate 131 via a via 152a penetrating the substrate 131. The connection electrode 153a becomes conductive when the connection electrode 154a formed on the first surface 121a of the substrate 121 and the substrate 121 and the substrate 131 come into contact with each other by tightening the screw 55 to the holding member 11a. The connection electrode 154a is electrically connected to the ground line 123 of the input waveguide 120 via a via 155a penetrating the substrate 121. As a result, one damping resistor 50a is electrically connected to the ground line 123 of the input waveguide 120 and the ground line 133 of the output waveguide 120. Similarly, the other damping resistor 50b is electrically connected to the ground line 123 of the input waveguide 120 and the ground line 133 of the output waveguide 130 via the electrodes 151b, via 152b, connecting electrodes 153b, 154b and via 155b. Is connected.

The damping resistors 50a and 50b are arranged symmetrically on both sides of the exciting portion 122b and the detecting portion 132b. As a result, resonance on the high frequency side can be effectively suppressed. As the damping resistors 50a and 50b, a damping resistor having the same resistance value as the combined resistance value may be used for only one of them. The arrangement of the damping resistors 50a and 50b is not limited to this.

The principle of measuring the magnetic permeability by the magnetic permeability measuring jig 100 is the same as that of the magnetic permeability measuring jig 10. The width of the detection unit 132b and the excitation unit 122b, and the relationship between the width and the distance between the detection unit 132b and the excitation unit 122b are the same as those of the magnetic permeability measuring jig 10.

According to this embodiment, the magnetic permeability measuring jig 100 has the same effect as the magnetic permeability measuring jig 10 of the previous embodiment. The input waveguide 120 and the output waveguide 130 have a microstrip line structure, and the excitation unit 122b and the detection unit 132b, which are signal lines, can be miniaturized, and the excitation unit 122b and the detection unit 132b can be reduced. Since it is possible to easily arrange the minute magnetic powder in close proximity to the simple substance, the measurement sensitivity of the magnetic permeability can be improved. The exciting unit 122b and the detecting unit 132b are terminal portions short-circuited with the ground lines 123 and 133, respectively, and the exciting unit 122b and the detecting unit 132b are arranged so as to face each other, so that the influence of the electric field can be suppressed. .. The detection signal of the detection unit 132b is a signal due to an induced electromotive force due to the movement of magnetization of the sample 46, but a signal due to the influence of an excitation signal from the excitation unit 122b is also added. Since the voltage of the signal due to the detection signal and the excitation signal is proportional to the frequency, the ratio is the same. Therefore, the magnetic permeability measuring jig 100 can obtain a constant measurement sensitivity over the entire measurement frequency. In the magnetic permeability measuring jig 100, since the damping resistors 50a and 50b are electrically connected between the ground line 123 of the input waveguide 120 and the ground line 133 of the output waveguide 120, the magnetic permeability measuring jig 100 is used. The resonance of the LC resonance circuit generated by the tool 100 can be suppressed, and more accurate measurement of magnetic permeability becomes possible. The magnetic permeability measuring jig 100 can extremely suppress a decrease in measurement sensitivity that occurs on the low frequency side in the measuring devices described in Patent Document 1 and Non-Patent Document 1.

FIG. 13 is a diagram showing transmission characteristics with respect to damping resistance of the magnetic permeability measuring jig according to the embodiment of the present invention. The jig for measuring magnetic permeability shown in FIGS. 1 to 4 was used. The horizontal axis of FIG. 13 indicates the frequency of the excitation signal, and the vertical axis is _{the absolute value of S 21} of the S parameter, which is the transmission coefficient from the input side to the output side of the magnetic permeability measuring jig. The braking coefficient ζ and damping resistance value are shown on the right side of the characteristic line.

With reference to FIG. 13, when the frequency is 1 GHz to 6 GHz, the damping resistance value (combined value of two parallel damping resistors 50a and 50b) becomes almost linear in the range of 9Ω to 280Ω, and is used for magnetic permeability measurement. It can be seen that the resonance of the LC resonance circuit formed by the jig is suppressed. It is preferable to set the resistance value of the damping resistor in this range. The magnetic permeability measuring jig used here had a resonance frequency of 1.07 GHz without a damping resistor (the lowest characteristic line shown in FIG. 13) and an inductance L of 8.4 nH. Therefore, the braking coefficient ζ is expressed by the following equation (2).
ζ = 28 / Rd ・ ・ ・ (2)
Here, Rd is the resistance value (Ω) of the damping resistor. Therefore, it can be seen that the braking coefficient ζ corresponding to R = 9Ω to 280Ω is 0.1 to 3, and it is preferable to select the resistance value of the damping resistance so that the braking coefficient ζ is 0.1 to 3.

[Example]
The complex magnetic permeability of one permalloy magnetic powder as a sample by the magnetic permeability measuring method shown in FIG. 8 using the magnetic permeability measuring device shown in FIG. 7 including the magnetic permeability measuring jig 10 shown in FIGS. 1 to 4. Was measured. The magnetic powder is _{an amorphous flat body having a composition of Ni 80} Fe ₂₀ (atomic%), a size of about 180 μm × 100 μm, and a thickness of 0.5 μm. The magnetic powder was attached to the exciting portion using a polyimide tape having a thickness of 35 μm having an adhesive on one surface, and arranged so that the detection portion was in contact with the other surface.

As for the DC magnetic field applied by the electromagnet, a predetermined magnetic field (n = 1) was set to no magnetic field (zero T), and the saturated magnetic field was set to 1.5 T. The measurement frequency was set to 10 MHz to 20 GHz, and the power and bandwidth of the excitation signal were set as shown in the table below. A vector network analyzer (model: N5222A) manufactured by Keysight Technology, Inc. of the United States was used as the signal generation analysis unit 64. As the low noise amplifier 62, a wideband low noise amplifier (model: AH14149A) manufactured by Anritsu Co., Ltd. was used.

FIG. 14 is a diagram showing the frequency characteristics of the complex magnetic permeability of the examples according to the present invention. With reference to FIG. 14, the complex magnetic permeability is stable over 10 MHz to 20 GHz in the real part and the imaginary part of the complex magnetic permeability even with a small magnetic powder having a size of about 100 μm to 300 μm and a thickness of 1 μm to 2 μm. It can be seen that the measurement can be performed accurately. The correction coefficient C is 8.7 × 10 ^-5 .

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and modifications are made within the scope of the present invention described in the claims. Is possible.

10,100 Permeability measurement jig 20, 120 Input waveguide 21, 31, 121, 131 Substrate 22, 32, 122, 132 Signal line 22b, 122b Excitation unit 23, 33, 123, 133 Ground line 30, 130 Output waveguide 32b, 132b Detection unit 47 Non-magnetic insulating layer 50, 50a, 50b Damping resistance 60 Permeability measuring device 64 Signal generation analysis unit 70 DC magnetic field generation unit 80 Control calculation unit

Claims (12)

The first waveguide, wherein the signal line has an exciting portion that generates a magnetic field by an excitation signal on one end side.
In the second waveguide, the signal line has a detection unit on one end side in which a magnetic field generated in the excitation unit acts on a measurement sample to induce a detection signal, and the detection unit is placed on the excitation unit. The second waveguide, which is arranged so as to face each other at a predetermined distance,
A jig for measuring magnetic permeability, comprising a damping resistor connected between the ground line of the first waveguide and the ground line of the second waveguide. The magnetic permeability measuring jig according to claim 1, wherein the damping resistance suppresses resonance of a resonance circuit formed by the magnetic permeability measuring jig. The magnetic permeability measurement according to claim 2, wherein the resonance circuit is an LCR resonance circuit, and the damping resistance is selected so that the braking coefficient of the LCR resonance circuit is in the range of 0.1 or more and 3.0 or less. Jig. The first waveguide and the second waveguide have a signal line on the main surface of the first dielectric substrate and the second dielectric substrate, and ground lines on both sides thereof, respectively, and the signal line The jig for measuring magnetic permeability according to any one of claims 1 to 3, wherein a short circuit is made with each of the ground lines at one end of each of the exciting unit and the detecting unit. The damping resistor is connected to a ground line on one side of the first waveguide with respect to the signal line and a ground line on the same side as the one side of the second waveguide with respect to the signal line. , The jig for measuring magnetic permeability according to claim 4. The damping resistance is two resistance elements, one of which is the ground line on one side of the signal line of the first waveguide and the one side of the signal line of the second waveguide. The other resistance element is connected to the ground line on the same side as the ground line on the other side of the signal line of the first waveguide and the signal line of the second waveguide. The jig for measuring magnetic permeability according to claim 4, which is connected to a ground line on the same side as the other side. The first and second waveguides each have a signal line on the surface of the dielectric substrate and a ground line on the back side of the dielectric substrate, and the signal line is each of the excitation unit and the detection unit. The jig for measuring magnetic permeability according to any one of claims 1 to 3, which is short-circuited with each of the ground lines at one end of the above. The jig for measuring magnetic permeability according to any one of claims 1 to 7,
A signal generation means connected to the input portion of the magnetic permeability measuring jig to generate the excitation signal, and
A signal analysis means connected to the output unit of the magnetic permeability measuring jig and analyzing the detection signal,
An arithmetic means for obtaining magnetic permeability from the analyzed signal, and
A magnetic permeability measuring device. The magnetic permeability measuring apparatus according to claim 8, further comprising an excitation signal control means for controlling the signal generation means so as to supply the excitation signal with a power larger than that on the high frequency side on the low frequency side to the input unit. The magnetic permeability measuring apparatus according to claim 8 or 9, further comprising an amplification means for amplifying the detection signal between the output unit and the signal analysis means. The invention according to any one of claims 8 to 10, further comprising a DC magnetic field applying means for applying a DC magnetic field along the transmission direction of the excitation signal and the detection signal to the exciting portion and the detecting portion of the magnetic permeability measuring jig. Permeability measuring device. A method for measuring magnetic permeability using the magnetic permeability measuring device according to any one of claims 8 to 11.
It is a step of setting the power of the excitation signal for each measurement band, inputting the excitation signal, and measuring the detection signal. The method comprising the step of controlling the signal generating means to supply the excitation signal.

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