JP2008039703A - Electromagnetic characteristic measuring tool and measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic characteristic measuring tool and a measuring method therefor capable of measuring temperature dependency of the electromagnetic characteristic, and measuring even in the case of a measuring specimen having any thickness or any relative dielectric constant. <P>SOLUTION: The electromagnetic characteristic measuring tool constituted of a cylindrical cavity resonator having a cylindrical conductor and a short-circuit board includes a functional structure for separating TE<SB>01P</SB>mode (p is an optional integer) from TM<SB>11P</SB>mode on the inner wall surface of the cylindrical cavity resonator. In the measuring method of the electromagnetic characteristic, a signal having a fixed magnitude is imparted to the electromagnetic characteristic measuring tool, and the magnitude of an output signal to a frequency of the signal is measured, by using a measuring system equipped with the electromagnetic characteristic measuring tool, and the electromagnetic characteristic is acquired from a resonance frequency and a Q-value acquired thereby. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to measurement of electromagnetic characteristics.

As a conventional method for measuring electromagnetic characteristics in the microwave and millimeter wave bands, there is a method using a cylindrical cavity resonator TE _01P mode. The TE _01P mode used for measurement by this method is characterized by degeneration from the TM _11P mode. Therefore, in order to measure the surface resistance of the cavity resonator, it is necessary to separate the TE _01P mode and the TM _11P mode. Conventionally, the TE _01P mode and the TM _11P mode are separated by a method of loading a dielectric into a cavity resonator (see, for example, Non-Patent Document 1) or a method of providing a groove in a cavity resonator (for example, a non- (See Patent Document 2).

However, in the method of loading a dielectric on a cavity resonator, the TE _01P mode shift is small and the measurement is affected by the TM _11P mode when the measurement specimen is thin or the dielectric constant is close to 1. Can not. In addition, since the adhesive used to load the dielectric to the cavity resonator is used, when measuring outside the heat resistant temperature range of the adhesive, the dielectric will fall off, and the temperature dependence of the electromagnetic characteristics Measurement is not possible.
Also, in the method of providing a groove in the cavity resonator, the TM _11P mode shifts to the low frequency side of the TE _01P mode, so depending on the thickness and relative dielectric constant of the sample to be measured, it shifts due to the electromagnetic characteristics of the sample to be measured. The TE _01P mode was affected by the TM _11P mode, and measurement was not possible.

JIS-R1641, 2002 Ma, Tanaka, Kobayashi, IEICE Technical Report SCE, MW 2001-7, p39-44, 2001

  The present invention is capable of measuring the temperature dependence of electromagnetic characteristics in the measurement of electromagnetic characteristics using a cylindrical cavity resonator, and can measure any thickness or relative dielectric constant of a measurement specimen. A measuring jig and its measuring method are provided.

The present inventor separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode on the inner surface of the cylindrical conductor and / or the short-circuit plate in the measurement of electromagnetic characteristics by the cylindrical cavity resonator. By providing a functional structure for reducing the influence of the TM _11P mode by shifting the TM _11P mode to a higher frequency side than the TE _01P mode, a measurement specimen having any thickness and relative dielectric constant can be _By using the _01P mode, it was found that the electromagnetic characteristics of the measurement specimen can be measured, and further investigations have led to the completion of the present invention.

The present invention is achieved by the following electromagnetic characteristic measuring jig and electromagnetic characteristic measuring method.
(1) An electromagnetic characteristic measurement jig comprising a cylindrical cavity resonator having a cylindrical conductor and a short-circuit plate, wherein a TE _01P mode (p is an arbitrary integer) is _formed on the inner wall surface of the cylindrical cavity resonator. ) And the TM _11P mode are provided with a functional structure.
(2) The functional structure that separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is such that the value of the electromagnetic field intensity of the TE _01P mode (p is an arbitrary integer) indicates a minimum value. The electromagnetic characteristic measuring jig according to item (1), which is provided at one position.
(3) The functional structure that separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided on all or part of the circumference of the inner wall surface of the cylindrical conductor ( The electromagnetic characteristic measuring jig according to item 1) or item (2).
(4) The functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided in an arbitrary shape on a part of the inner wall of the short-circuit plate (1) The electromagnetic characteristic measuring jig according to any one of Items 1 to (3).
(5) The functional structure that separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode has any one of the items (1) to (4) whose sectional structure is convex. The electromagnetic characteristic measuring jig described in 1.
(6) The electromagnetic characteristic measuring jig according to any one of (1) to (5), wherein the electromagnetic measuring jig has a holding portion for a measurement specimen in the cylindrical conductor. .
(7) The electromagnetic characteristic measurement jig according to (6), wherein the measurement specimen holding unit is provided at a position where the TE _01P mode (p is an arbitrary integer) shows a maximum value.
(8) A method of measuring an electromagnetic characteristic of a measurement sample using a measurement system including the electromagnetic characteristic measurement jig, wherein a signal having a certain magnitude is given to the electromagnetic characteristic measurement jig, and the signal A method for measuring electromagnetic characteristics, characterized in that electromagnetic characteristics are obtained from a resonance frequency and a Q value obtained by measuring the magnitude of an output signal with respect to a certain frequency.

  According to the present invention, it is possible to measure the electromagnetic characteristics of a measurement specimen having any thickness and relative dielectric constant in the microwave and millimeter wave bands. In particular, it is suitable for measurement of a thin measurement specimen that cannot be measured by a conventional method or a low dielectric constant measurement specimen. In addition, it is possible to perform measurement in a temperature range where the dielectric cannot be loaded by the conventional method.

The present invention relates to an electromagnetic characteristic measuring jig comprising a cylindrical cavity resonator having a cylindrical conductor and a short-circuit plate, and a TE _01P mode (p is an arbitrary _value) on the inner wall surface of the cylindrical cavity resonator. It is an electromagnetic characteristic measurement jig provided with a functional structure for separating an integer) and a TM _11P mode.

The function of separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode in the present invention is to eliminate the degeneracy (overlap) between the TE _01P mode and the TM _11P mode when measuring electromagnetic characteristics. The TE _01P mode curve is shifted, and in the present invention, the cylindrical conductor and / or the short circuit has a structure that expresses the function of separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode. By providing it on the inner wall surface of the plate, the TE _01P mode curve can be shifted to the high frequency side, thereby reducing the influence on the measurement due to the decrease (overlap) of the TM _11P mode curve. Electromagnetic properties can be measured without being affected by the thickness and dielectric property values.

The electromagnetic characteristic measuring jig of the present invention is composed of a cylindrical cavity resonator having at least a cylindrical conductor and a short-circuit plate. On the inner wall surface of the cylindrical conductor and / or the short-circuit plate, a TE _01P mode is provided. (P is an arbitrary integer) and a functional structure for separating the TM _11P mode is provided.

  The cylindrical conductor has a structure in which both ends of the cylinder, that is, both ends in the direction perpendicular to the circumference of the cylinder are short-circuited by a short-circuit plate, and the measurement specimen is placed at a predetermined position inside the cylindrical conductor. If the measurement specimen can form a structure having two cavities, for example, when the cylindrical conductor is constituted by one, both ends of the cylinder are short-circuited by a short-circuit plate. The measurement specimen is a structure having two cavities that are held at a predetermined position of the cylindrical conductor and short-circuited by the measurement specimen. Moreover, when the said cylindrical conductor is comprised by two, it has the structure where one end of the cylinder was short-circuited by the short circuit board, and the other end was open | released, The said cylindrical shape is used using a pair of this cylindrical conductor. One example is a structure having two cavities in which the open portions of the conductors are held in accordance with the measurement sample and blocked by the measurement sample. Furthermore, in order to adjust the position where the measurement specimen is held, a cylindrical conductor having both ends opened may be used in combination with the cylindrical conductor having one end opened.

As a position where a functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided, the electromagnetic field intensity value of the TE _01P mode (p is an arbitrary integer) indicates the minimum value. For example, when p is 1, it is preferably provided at one or two positions, and when p is 2, it is provided at one, two or three positions. It is preferable to provide it.
Here, the position for holding the measurement specimen may be any position other than the position where the functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided. It is preferable to adjust the position appropriately according to the characteristics, and it is preferable that the value of the electromagnetic field intensity in the TE _01P mode is the position where the _maximum value is shown.

The functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is preferably provided in a predetermined position on the inner wall surface of the cylindrical cavity resonator, in whole or in part, When it is all, for example, it may be all in a ring shape, and when it is a part, for example, a structure having a deficient portion or a protrusion may be arranged in the ring structure. In the cylindrical cavity resonator, these functional structures are provided on the inner wall surface when the cylindrical conductor is provided on the inner wall surface circumference, and on the inner wall surface when provided on the short circuit plate. It is preferable to be provided on the top, and more preferably to be provided on a part of the short-circuit plate.

The shape of the functional structure that separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode may be any shape that protrudes more on the inner wall surface, and its cross-sectional structure is convex. It is preferable. As the shape of the convex portion, the cross-sectional shape thereof may be, for example, a polygonal shape such as a triangle and a quadrangle, a semicircular shape (dome shape), a circular shape and an elliptical shape, but a quadrangle is preferable.

The measurement jig in the present invention will be described in more detail with reference to the drawings.
1 to 3 are schematic views showing a simplified example of the measurement jig of the present invention. As a functional structure for separating the TE _01P mode and the TM _11P mode, the cross-sectional shape is a quadrangle and a cylindrical conductor. And the example at the time of forming in a ring shape in a short circuit board is demonstrated.
As an electromagnetic characteristic measuring jig of the present invention, a first example (FIG. 1) includes one cavity resonator (cylindrical conductor 1 and short-circuit plate 0) and the cavity resonator (on the short-circuit plate, cylindrical conductor). The measurement sample 3 is mounted inside the resonator and is cut off by the measurement sample. It has the structure which has. In addition, the convex part is provided at two positions where the TE _01P mode electromagnetic field intensity shows the minimum value, and the measurement specimen is an example where the TE _01P mode is arranged at the maximum position.

The height of the ring-shaped convex portion from the short-circuit plate (the thickness in the left-right direction in FIG. 1) is 1/200 or more of the length of the resonator (cylinder) (the length in the left-right direction in FIG. 1), 1/10 The following are preferable, and 1/80 or more and 1/40 or less are more preferable. The width of the ring-shaped convex portion (the thickness in the direction perpendicular to the height of the convex portion, the thickness in the vertical direction in FIG. 1) is 1/100 or more of the resonator (cylinder) diameter (the length in the vertical direction in FIG. 1), 1/5 or less is preferable and 1/50 or more and 1/25 or less are more preferable. These dimensions are appropriately adjusted according to the separation state between the TE _01P mode and the TM _11P mode.
The position of the measurement sample 3 is at the center of the length of the resonator (cylinder) (the length in the left-right direction in FIG. 1), but it is preferable to adjust the position appropriately according to the electromagnetic characteristics of the measurement sample.

  In the case of measuring non-destructively, the electromagnetic characteristic measuring jig of the present invention may be provided with the measurement specimen insertion portion 4 in the cavity resonator (cylindrical conductor 1 and short-circuit plate 0). As a second example (FIG. 2). In this case, two cylindrical conductors having a structure in which the cavity resonator (cylindrical conductor) is divided into two parts, that is, one end of the cylinder is short-circuited by a short-circuit plate and the other end is opened, are prepared. A structure having two cavities in which the cavity resonator is cut off by the measurement specimen is configured by sandwiching the measurement specimen 3 between the open portions of the two cylindrical conductors. It is done. When the cavity resonator (cylindrical conductor) is divided into two, the holding position of the measurement specimen can be determined as appropriate by adjusting the lengths of the two cylindrical conductors used in combination.

  At this time, the thickness of the measurement sample insertion portion 4 is preferably the same as the thickness of the measurement sample, and the length of the cylinder is preferably adjusted by the thickness of the measurement sample insertion portion 4. When the measurement specimen is sandwiched between the divided cavity resonators, the sandwiching pressure is preferably 10 hPa to 10 MPa, and more preferably 100 hPa to 1 MPa. In addition, it is preferable that a slide, a knock pin, or the like is provided in the divided cavity resonator so that the relative positions of the divided cavity resonator and the measurement specimen do not shift.

Here, when the measurement specimen is a powder, a film having poor self-supporting property such as warping or wrinkling, the measurement specimen can be measured by being sandwiched between two supporting dielectrics. The supporting dielectric is not limited as long as it is composed of a dielectric and exhibits the properties of the dielectric, but the dielectric preferably has a dielectric loss tangent of 10 ⁻³ or less and 0 or more, More preferably, 10 ⁻⁴ or less and 0 or more.

In the second example, when the measurement sample is soft and difficult to pinch, the size of the measurement sample insertion portion can be fixed with the spacer 5 or the like (FIG. 3).
As the material of the spacer, an insulator, a metal, or the like can be used, and the shape of the spacer may be any material that can hold the measurement specimen. The size is preferably a size obtained by adding 1 to 500 μm to the thickness of the sample to be measured, and more preferably a size obtained by adding 10 to 200 μm.
The position where the spacer is provided may be a position where the measurement specimen is sandwiched between two cylindrical conductors in the cavity resonator, and may be a position where the spacer does not protrude from the inner wall surface of the cylindrical conductor. In this case, the outside of the sample to be measured is preferable. By providing the spacer, the conductor holding part may be an open part.

  The cavity resonator (cylindrical conductor 1 and short-circuit plate 0) used in the present invention is preferably made of metal, particularly metal having high conductivity. Examples of the metal having a high conductivity include silver, copper, and gold. In addition, when a metal cannot be used for a cavity resonator, the same effect as the cavity resonator using a metal can be acquired by plating the above-mentioned metal on the surface of a cavity resonator.

  The dimensions of the cavity resonator (cylindrical conductor and short-circuit plate) are determined by the frequency to be measured. At this time, it is preferable to confirm that the mode used for measurement is not affected by the mode not used for other measurements by referring to a mode chart or the like in advance.

  In the present invention, the electromagnetic characteristics can be measured by measuring the resonance characteristics of the cavity resonator in the microwave and millimeter wave bands using a measurement system equipped with an electromagnetic characteristic measurement jig.

In the present invention, as a measurement system for measuring the electromagnetic characteristics of a measurement specimen using the measurement system including the electromagnetic characteristic measurement jig, for example, the electromagnetic characteristic measurement jig of the present invention and a network analyzer are connected. The thing which was done is mentioned.
The measurement by the network analyzer is performed by connecting an object to be measured (the electromagnetic characteristic measuring jig) and a terminal (port) of the network analyzer, and the reflected power from the electromagnetic characteristic measuring jig with respect to the power incident from the network analyzer. This can be done by measuring the transmitted power.
Referring to FIG. 4, two ports can be connected to the electromagnetic characteristic measuring jig, power can be incident from port 1, reflected power can be measured at port 1, and transmitted power can be measured at port 2.
A cable (transmission path) and a connector (coupling portion) are installed and connected to a connection portion between the electromagnetic characteristic measurement jig and the network analyzer (vector network analyzer in FIG. 4). In addition, a waveguide, a coaxial line, etc. can be used for a transmission line, and a probe coupling, a loop coupling, a hole coupling, etc. can be used for a coupling part.

As a method for measuring electromagnetic characteristics of the present invention, using a measurement system equipped with the electromagnetic characteristic measurement jig, a measurement specimen is mounted on the electromagnetic characteristic measurement jig, and a cavity resonator has a certain size. , And the magnitude of the output signal with respect to the frequency is measured. From the resonance frequency (hereinafter abbreviated as f) of the cavity resonator and the no-load Q value (hereinafter abbreviated as Q ₀ ) The electromagnetic characteristics of the measurement specimen can be measured using the field calculation. Examples of the electromagnetic field calculation method include a rigorous method using algebra, a numerical calculation using an electromagnetic field simulator, and a perturbation method.

Furthermore, an example in the case of calculating by the perturbation method will be described. The perturbation method in this case is used to obtain a change in resonance frequency and Q ₀ when a minute body having a different complex permittivity ε _r and complex permeability μ _r exists in a part of the cavity resonator. It is a technique. This example is a commonly used first-order approximation perturbation method, and it is considered that the electromagnetic field outside the measurement sample when a micro object is present is the same as the electromagnetic field when there is no measurement sample.

ここで
f₀：被測定検体が存在しない時の共振周波数
f：被測定検体が存在するときの共振周波数
E₀：被測定検体が存在しない時の共振器内の電界
H₀：被測定検体が存在しない時の共振器内の磁界
E：被測定検体が存在する時の共振器内の電界（ E₀；摂動法より）
H：被測定検体が存在する時の共振器内の磁界（ H₀；摂動法より）
J_e：電流源
J_m：磁流源
χ_e：電界係数(=ε_r−１)
χ_m：磁界係数(=μ_r−１)
V：共振器の体積
ΔV：被測定検体の体積
である。
したがって、電界係数や磁界係数が測定することができ、本発明における被測定検体の電磁気特性である、誘電特性及び透磁特性を算出することができる。

here
f ₀ : resonance frequency when there is no sample to be measured
f: Resonance frequency when the sample to be measured exists
E ₀ : Electric field in the resonator when there is no sample to be measured
H ₀ : Magnetic field in the resonator when there is no sample to be measured
E: Electric field in the resonator when the sample to be measured exists (E ₀ ; from perturbation method)
H: Magnetic field in the resonator when the sample to be measured is present (H ₀ ; from the perturbation method)
J _e : Current source
J _m : Magnetic current source χ _e : Electric field coefficient (= ε _r −1)
χ _m : magnetic field coefficient (= μ _r −1)
V: Volume of resonator ΔV: Volume of sample to be measured.
Therefore, the electric field coefficient and the magnetic field coefficient can be measured, and the dielectric characteristics and the magnetic permeability characteristics, which are the electromagnetic characteristics of the sample to be measured in the present invention, can be calculated.

  When measuring the temperature dependence of dielectric properties and magnetic permeability properties by the measurement method, the electromagnetic property measurement jig is placed in a temperature-adjustable measurement chamber or temperature control tank, and the electromagnetic properties are obtained by the method described above. be able to.

According to the present invention, it is possible to measure the electromagnetic characteristics of a solid insulator such as plastic, ceramics, and paper, and its temperature dependency.
As the thickness of the measurement specimen, for example, a thickness of 1 μm or more and 2 mm or less can be measured, but even a thicker sample can be measured and is not limited to this range. The range of the relative dielectric constant that can be measured is, for example, preferably 1.01 or more and 100 or less, but is not limited to this range.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by this.

  The measuring apparatus will be described with reference to FIG. 4. The cavity resonator 12 (electromagnetic characteristic measuring jig of the present invention) and the input / output port, port 1 and port 2 of the vector network analyzer 11 are connected. Electric power (incident power) was input, and the ratio of reflected power and transmitted power in the cavity resonator 12 was measured by a vector network analyzer.

[Example of temperature dependence measurement of electromagnetic characteristics]
(Example 1)
Measurement of a commercially available polyimide film having a thickness of 10 μm 0.5 mm in height and width at the contact point between a cylindrical conductor having a length of 30 mm and an inner diameter of 42 mm, a short circuit plate, and the cylindrical conductor on the inner surface of the short circuit plate Using a cylindrical cavity resonator with a ring-shaped convex part of 0.5 mm, the polyimide film of the measurement sample is divided into two cylindrical conductors of the cavity resonator as shown in FIG. did. In the measurement, the cavity resonator was placed in a thermostatic chamber, and the temperature was changed from −30 ° C. → 23 ° C. → 85 ° C. → 120 ° C. At each temperature, the cavity resonator and the vector network analyzer (Agilent Technology ( 8510C (hereinafter, abbreviated as VNA) was magnetically excited by a loop antenna through a connector, the transmission power ratio was measured, and the electromagnetic characteristics were calculated by the perturbation method. The polyimide film of the measurement specimen had a relative dielectric constant of 3.76 at 10 GHz at 23 ° C. according to JIS-R1641 method.

[Example when measuring sample insertion part is fixed]
(Example 2)
Measurement of commercially available polystyrene foam with a thickness of 1 mm 0.5 mm in height and width at the contact point between a cylindrical conductor with a length of 30 mm and an inner diameter of 42 mm, a short circuit plate, and the cylindrical conductor on the inner surface of the short circuit plate Using a cylindrical cavity resonator having a ring-shaped convex part of 0.5 mm, the measurement sample foaming polystyrene divides the cylindrical conductor of the cavity resonator into two, and the measurement sample insertion part is a 1.2 mm thick spacer The measurement specimen was fixed and measured. In the measurement, the cavity resonator and the VNA were magnetically coupled by a loop antenna via a connector, and the transmitted power ratio was measured. At that time, as shown in FIG. 3, the central portion of the cavity resonator cylindrical conductor was cut to form an insertion portion (4) for the measurement sample, and a 1.2 mm thick insulating plate was used as the spacer. In addition, the foamed polystyrene of the measurement specimen had a relative dielectric constant of 1.03 at 10 GHz according to JIS-R1641 method.

It is sectional drawing which shows the example of the measurement jig | tool equipped with the measurement sample for demonstrating this invention. It is sectional drawing for demonstrating the example at the time of using the insertion part of a measurement sample in this invention. It is sectional drawing for demonstrating the example at the time of fixing the insertion part of the measurement sample in this invention. It is explanatory drawing which shows an example of the setup of the measuring apparatus of this invention.

Explanation of symbols

0: Short-circuit plate 1: Cylindrical conductor 2: Ring-shaped convex part 3: Measurement specimen 4: Measurement specimen insertion part 5: Spacer 11: Vector network analyzer 12: Cavity resonator

Claims (8)

An electromagnetic property measurement jig comprising a cylindrical cavity resonator having a cylindrical conductor and a short-circuit plate, wherein a TE _01P mode (p is an arbitrary integer) and TM are _formed on the inner wall surface of the cylindrical cavity resonator. An electromagnetic characteristic measuring jig provided with a functional structure for separating the _11P mode. The functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is at least one position where the value of the electromagnetic field intensity of the TE _01P mode (p is an arbitrary integer) indicates a minimum value. The electromagnetic characteristic measuring jig according to claim 1, wherein the jig is provided on the electromagnetic field. The functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided on all or a part of the inner wall surface circumference of the cylindrical conductor. 2. The electromagnetic characteristic measuring jig according to 2. The functional structure for separating the TE _01P mode (p is an arbitrary integer) and the TM _11P mode is provided in a part on the inner wall of the short-circuit plate in an arbitrary shape. The electromagnetic characteristic measuring jig according to any one of the above items. The electromagnetic characteristic measuring jig according to any one of claims 1 to 4, wherein the functional structure that separates the TE _01P mode (p is an arbitrary integer) and the TM _11P mode has a convex cross-sectional structure. .   The electromagnetic characteristic measuring jig according to any one of claims 1 to 5, wherein the electromagnetic measuring jig has a holding portion for a measurement specimen on the cylindrical conductor. The electromagnetic property measuring jig according to claim 6, wherein the measurement specimen holding portion is provided at a position where the TE _01P mode (p is an arbitrary integer) shows a maximum value.   A method of measuring an electromagnetic characteristic of a measurement specimen using a measurement system including the electromagnetic characteristic measuring jig, wherein a signal having a certain magnitude is given to the electromagnetic characteristic measuring jig and the frequency of the signal is measured. A method of measuring electromagnetic characteristics, wherein electromagnetic characteristics are obtained from a resonance frequency and a Q value obtained by measuring the magnitude of an output signal.

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