JP6986260B2 - Substance identification device and identification method using electromagnetic waves - Google Patents

Description

The present invention relates to a substance identification device and an identification method using electromagnetic waves, and more specifically, to transmit electromagnetic waves having a plurality of frequencies to a cavity resonator and to receive the transmitted or reflected electromagnetic waves based on the resonance frequency and amplitude. Regarding devices and methods for identifying substances.

As a non-destructive evaluation method for identifying a substance, there is a method using the correlation between the resonance frequency change and the amplitude change at the resonance frequency. For example, Non-Patent Document 1 proposes a method for identifying the water content of Azuki in agricultural products. Azuki is placed in a cavity resonator, microwaves are irradiated, and the resonance frequency change in one electromagnetic resonance mode. And discloses that the water content is estimated using the amplitude change at the resonance frequency.

However, the method of Non-Patent Document 1 requires information on the particle size (thickness diameter, width diameter) of each adzuki bean, and the measurement must be performed one by one. Therefore, there is a problem that it takes a long time to evaluate a large number of samples.

On the other hand, as an evaluation method for nondestructively identifying a substance regardless of the amount of sample, there is a method using the correlation between amplitude change and phase change. Patent Document 1 discloses a water content measuring device / method for detecting a water content by analyzing an amplitude change and a phase change of a microwave at a single frequency.

However, the measurement of the phase change used by the method of Patent Document 1 has a problem that the system becomes complicated and the price of the apparatus is high.

Japanese Unexamined Patent Publication No. 2015-161597

Kumabayashi et al., "Non-destructive moisture measurement of adzuki bean grains using microwave sensor" Hokkaido Prefectural Food Processing Research Center Report, No. 3 (1998)

It is an object of the present invention to provide an evaluation device / method for identifying a substance regardless of the amount of sample and without measuring the phase change.

One aspect of the present invention provides an apparatus for identifying a substance using electromagnetic waves. The device is a cavity resonator that can contain a substance, and an electromagnetic wave for measuring the resonance frequency and amplitude of the transmitted or reflected electromagnetic wave from the cavity resonator that transmits and receives electromagnetic waves of multiple frequencies to the cavity resonator. It is provided with a measuring means and an analysis means for identifying a substance contained in the cavity resonator from the resonance frequency change and the amplitude change of the measured electromagnetic wave.
The analysis means detects (i) the resonance frequency change of the electromagnetic wave measured in response to the change in the amount of known substance in the cavity resonator, the amplitude change at the resonance frequency, and the amplitude change at a specific frequency. The correlation of the resonance frequency change in two different electromagnetic field modes, the correlation of the resonance frequency change and the amplitude change at the resonance frequency, and the correlation of the amplitude change at a specific frequency were obtained, and (ii) the substance to be inspected was detected. The material to be inspected is identified by applying a change in resonance frequency, a change in amplitude at the resonance frequency, or a change in amplitude at a specific frequency to one of the corresponding correlations for a known material.

One aspect of the present invention provides a method for identifying a substance using electromagnetic waves. The identification method consists of (a) irradiating a hollow resonator containing an unknown substance with electromagnetic waves of multiple frequencies to receive the transmitted or reflected electromagnetic waves, and (b) the resonance frequency of the received electromagnetic waves. And (c) the resonance frequency of the cavity resonator in a state where it does not contain an unknown substance obtained in advance and the resonance frequency of the detected electromagnetic wave in two different electromagnetic field modes of the cavity resonator. A plurality of 2 previously obtained in steps (a) to (c) while changing the amount of the step of obtaining the frequency difference and (d) the frequency difference in two different electromagnetic wave modes for each of the plurality of known substances. It involves identifying unknown substances by fitting the correlation of frequency differences in two different electromagnetic wave modes.

According to the present invention, since the measurement can be performed in a non-contact and non-destructive manner, high throughput can be obtained, 100% inspection is possible, and real-time measurement is also possible online. According to the present invention, since it does not depend on the amount of the sample, accurate measurement can be performed regardless of the skill and experience of the measurer. According to the present invention, since the phase change is not measured, the system can be simplified and the device price can be reduced. According to the present invention, since there is a wide range of frequency selectivity of electromagnetic waves based on the same measurement principle, it is possible to select a frequency according to an object to be measured.

It is a figure which shows the structure of the identification apparatus of one Embodiment of this invention. It is sectional drawing which shows the structure of the cavity resonator of one Embodiment of this invention. It is a figure which shows the resonance characteristic at the time of changing the amount of water of one Embodiment of this invention. It is a figure which shows the resonance characteristic at the time of changing the amount of water of one Embodiment of this invention. It is a figure which shows the measurement result (resonance frequency change vs. resonance frequency change) of one Example of this invention. It is a figure which shows the measurement result (amplitude change vs. amplitude change) of one Example of this invention. It is a figure which shows the measurement result (resonance frequency change vs amplitude change) of one Example of this invention.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of an apparatus for identifying a substance using an electromagnetic wave according to an embodiment of the present invention (hereinafter referred to as an identification apparatus). The identification device 100 includes an analysis means 1, an electromagnetic wave measuring means 3, and a cavity resonator 6. The analysis means 1 is composed of, for example, a personal computer (PC), and performs various processes (analysis) for the identification method of the present invention described later under the execution of predetermined software.

The electromagnetic wave measuring means 3 is composed of, for example, a network analyzer, and is connected to each other so as to be communicable with each other via an analysis means 1 (hereinafter referred to as a PC) and a cable 2 (for example, a GP-IB cable, a USB cable, etc.). Network analyzers include vector network analyzers and scalar network analyzers. Since phase measurement is not performed in the present invention, the latter scalar network analyzer can also be used.

The electromagnetic wave measuring means 3 (hereinafter referred to as a network analyzer) is communicably connected to the cavity resonator 6 via coaxial cables 4 and 5 connected to the input / output ports 7 and 8. The network analyzer 3 transmits electromagnetic waves having a plurality of frequencies to the cavity resonator 6 and measures the resonance frequency and amplitude of the transmitted or reflected electromagnetic wave from the received cavity resonator 6. The network analyzer 3 can transmit the measured frequency and amplitude data to the PC 1 via a cable, and at the same time can display them on the built-in monitor. The PC1 performs various analyzes for identifying the substance contained in the cavity resonator from the measured resonance frequency change and amplitude change of the measured electromagnetic wave. The contents of the analysis will be described later.

FIG. 2 is a cross-sectional view showing the configuration of the cavity resonator 6 according to the embodiment of the present invention. In FIG. 2, there are an electromagnetic wave input port and an output port on opposite side surfaces of a cylindrical metal container, and antenna probes 63 and 64 are provided in each port so as to project into the container. An elongated container (hereinafter referred to as a tube) 61 can be inserted from the upper side of the container toward the inside. The tube 61 in FIG. 2 has a shape like a test tube, but the shape of the tube is not limited to this, and may be a rectangular parallelepiped or the like, and the change in the amount of the injected substance can be visually observed. A container made of translucent glass or resin is preferable.

The sample (substance) 62, which is the object to be inspected, can be put into the tube 61 while the amount thereof is arbitrarily changed. The identification device 100 according to the embodiment of the present invention identifies the material in the tube 61. The cavity resonator that can be used in the present invention is not limited to the cylindrical cavity resonator 6 in FIG. 2, and a cavity resonator having another shape can also be used.

Hereinafter, a method for identifying a substance according to an embodiment of the present invention using the identification apparatus according to the embodiment of FIGS. 1 and 2 will be described with reference to FIGS. 3 to 7. First, the findings obtained by the inventors of the present application regarding the identification method of one embodiment of the present invention and the outline of the method will be described.

The present inventors focused on the resonance frequency change in the electromagnetic field resonance mode, the amplitude change (attenuation amount) at the resonance frequency, and the amplitude change at a specific frequency, and the change in the amount of the substance is the resonance of different electromagnetic field resonance modes. It has been found that it is detected as a correlation of frequency change, a correlation between a resonance frequency change and an amplitude change at a resonance frequency, or a correlation of an amplitude change at a specific frequency. Then, by measuring and plotting the resonance frequency change, the amplitude change at the resonance frequency, or the amplitude change at a specific frequency by changing the amount of the substance, the correlation peculiar to the substance can be obtained. I devised it.

That is, first, (a) the amount of various substances known in advance is changed, electromagnetic waves of a plurality of different frequencies are irradiated, and the frequency and amplitude of the electromagnetic waves transmitted or reflected by the substances are measured, and (b) resonance is performed. The frequency change, the amplitude change at the resonance frequency, and the amplitude change at a specific frequency are detected, and the correlation is obtained in advance. Next, (c) the object to be inspected is irradiated with electromagnetic waves of a plurality of different frequencies, and the frequency and amplitude of the electromagnetic waves transmitted or reflected through the object to be inspected are measured, and (d) the resonance frequency change and the resonance frequency are measured. It is possible to identify (evaluate and separate) the substance by detecting the change in amplitude and the change in amplitude at a specific frequency in (e) and applying it to the correlation obtained in advance. The above is the outline of the identification method.

Next, the identification method will be specifically described. In the following description, water, ethanol, wheat flour, and defatted milk powder are used as the substances to be inspected, based on an example (experimental result). The objects to be inspected by the method are not limited to these substances. That is, any substance such as a liquid or a solid, a viscous body, a granular body, or a powdery body can be arbitrarily selected as long as it is a substance that can be put into the tube 61 while changing its amount.

<Embodiment 1: When using the correlation of resonance frequency change>
First, prior to the measurement of the object to be inspected, tubes 61 containing different amounts of water known in advance are sequentially placed in the cavity resonator 6 of FIGS. 1 and 2, and the frequency 2 is measured by the network analyzer 3. It irradiates a plurality of different electromagnetic waves of ~ 4 GHz and receives the transmitted electromagnetic wave. FIG. 3 shows the electromagnetic resonance mode obtained by the network analyzer 3 when the amount of water is changed by three types ((1) amount of water 1, (2) amount of water 2, (3) amount of water 3). It is a graph which showed the example of the resonance characteristic (frequency vs. amplitude) of TE111. (0) is a case where water is not put in the tube 61. As the amount of water is increased to 1, 2, and 3 with respect to the resonance frequency of 2.628 GHz without water, the resonance frequency (resonance point), that is, the peak of each waveform of (1), (2), and (3) ( It can be seen that the frequency marked with) becomes smaller. At the same time, it can be seen that the amplitude at the resonance frequency (resonance point) gradually decreases.

FIG. 4 shows, as in the case of FIG. 3, when the amount of water obtained by the network analyzer 3 is changed by three types ((1) amount of water 1, (2) amount of water 2, (3) water. It is a graph which showed the example of the resonance characteristic (frequency vs. amplitude) of the electromagnetic field resonance mode TE211 of the quantity 3). (0) is a case where water is not put in the tube 61. As the amount of water is increased to 1, 2, and 3 with respect to the resonance frequency of 3.919 GHz without water, the resonance frequency (resonance point), that is, the peak of each waveform of (1), (2), and (3) ( It can be seen that the frequency marked with) becomes smaller. At the same time, it can be seen that the amplitude at the resonance frequency (resonance point) gradually decreases.

From the results (graphs) of FIGS. 3 and 4, the resonance frequency change A of the electromagnetic resonance mode TE111, that is, the frequency of 2.628 GHz of the peak (○) of the waveform (0) in FIG. 3 and (1) by PC1. ~ (3) The difference from the frequency at each resonance point (◆ mark) of the waveform and the resonance frequency change B of TE211, that is, the frequency of 3.919 GHz of the peak (○ mark) of the waveform (0) in FIG. The difference between the frequency and the frequency at each resonance point (marked with ◆) of the waveforms (1) to (3) is detected. Then, when the horizontal axis is plotted on the graph of the resonance frequency change A of TE111 and the vertical axis is plotted on the graph of the resonance frequency change B of TE211, it becomes as shown by ● in the graph of FIG. That is, in FIGS. 5 (0)-(1), (0)-(2), and (0)-(3), the resonance frequency change A of the electromagnetic field resonance mode TE111 of FIG. The resonance frequency change B of TE211 in FIG. 4 is plotted on the vertical axis.

After obtaining a graph of resonance characteristics (frequency vs. amplitude) similar to those in FIGS. 3 and 4 by putting ethanol in the tube 61 instead of water and changing the amount, the horizontal axis is the resonance frequency change A of TE111, and the vertical axis is vertical. When plotted on the graph of the resonance frequency change B of TE211 on the axis, it becomes as shown by the ▲ mark in the graph of FIG. The graph of water (● mark) and ethanol (▲ mark) in FIG. 5 is used as the correlation for substance identification. Prior to the measurement of the object to be inspected, the process until this correlation is obtained is performed in advance.

Next, the tube 61 containing the object to be inspected is installed in the cavity resonator 6, and the network analyzer 3 irradiates a plurality of different electromagnetic waves having a frequency of 2 to 4 GHz to receive the transmitted electromagnetic wave. If the resonance frequency change of the electromagnetic resonance mode TE111 and the resonance frequency change of TE211 are detected by the PC1 and applied to the correlation of the graph of FIG. 5 obtained in advance, the substance can be identified, that is, water in the example of FIG. It is possible to identify whether it is ethanol. If the same correlation as in FIG. 5 is obtained in advance for other known substances instead of water or ethanol, it is basically possible to identify other unknown substances.

<Embodiment 2: When using the correlation of the amplitude change at a specific frequency>
An example of a substance identification method using the correlation of amplitude change at a specific frequency is shown. Prior to the measurement of the object to be inspected, tubes 61 containing different amounts of water known in advance are sequentially installed in the cavity resonator 6, and electromagnetic waves having frequencies of 2.628 GHz and 3.919 GHz are measured by a network analyzer 3. Irradiates and receives the transmitted electromagnetic wave. The three ■ marks in FIG. 3 indicate the 2.628 GHz data when the amount of water is changed by three types ((1) amount of water 1, (2) amount of water 2, (3) amount of water 3). It is a graph which showed an example. (0) is a case where water is not put in the tube 61. Similarly, the three ■ marks in FIG. 4 are graphs showing an example of 3.919 GHz data when the amount of water is the same as described above.

These two frequencies, 2.628 GHz and 3.919 GHz, are transmission characteristics (frequency) measured in advance by irradiating the tube 61 of the cavity resonator 6 with water and ethanol in full (full tank) and irradiating electromagnetic waves with a frequency of 2 to 6 GHz. In vs. amplitude), it was selected as the frequency of the electromagnetic wave resonance modes TE111 and TE211 having a large amplitude change. Therefore, it is possible to select the frequency of another electromagnetic field resonance mode having a large amplitude change. Further, since the value of the resonance frequency changes if the type (shape) of the cavity resonator 6 and the material to be measured change, it is decided to appropriately select two resonance frequencies according to the type (shape) of the cavity resonator 6 and the like. Become.

Depending on the PC1, the amplitude change at a frequency of 2.628 GHz (difference between the amplitudes marked with ○ and the amplitude marked with ■ in FIG. 3) and the amplitude change at 3.919 GHz (difference between the amplitudes marked with ○ and the amplitude marked with ■ in FIG. 4). ) Is detected. Then, when the horizontal axis is plotted on the graph of the amplitude change at 2.628 GHz and the vertical axis is plotted on the graph of the amplitude change at 3.919 GHz, it becomes as shown by the ● mark in the graph of FIG. By the same procedure, a graph of the change in amplitude for ethanol is obtained as shown by the ▲ mark in FIG. The graph of water (● mark) and ethanol (▲ mark) in FIG. 6 is used as the correlation for substance identification. Prior to the measurement of the object to be inspected, the process until this correlation is obtained is performed in advance.

Next, the tube 61 containing the object to be inspected is installed in the cavity resonator 6, and the electromagnetic wave having a frequency of 2.628 GHz and 3.919 GHz is irradiated by the network analyzer 3 to receive the transmitted electromagnetic wave. If the amplitude change of the frequency 2.628 GHz and the amplitude change of 3.919 GHz are detected by PC1 and applied to the correlation of the graph of FIG. 6 obtained in advance, the substance can be identified, that is, water or ethanol in the example of FIG. Can be identified. If the same correlation as in FIG. 6 is obtained in advance for other known substances instead of water or ethanol, it is basically possible to identify other unknown substances.

<Embodiment 3: When the correlation between the resonance frequency change and the amplitude change at the resonance frequency is used>
An example of a substance identification method using the correlation between the resonance frequency change and the amplitude change at the resonance frequency is shown. Here, an example is shown in the case where wheat flour and skim milk powder are used instead of water and ethanol. Prior to the measurement of the object to be inspected, tubes 61 containing different amounts of wheat flour known in advance are sequentially installed in the cavity resonator 6, and a plurality of different electromagnetic waves having a frequency of 2 to 4 GHz are transmitted by a network analyzer 3. Receives electromagnetic waves that have been irradiated and transmitted.

When PC1 detects the change in resonance frequency of electromagnetic field resonance mode TE111 and the change in amplitude at the resonance frequency of TE211 and plots it on the graph of the change in resonance frequency of TE111 on the horizontal axis and the change in amplitude at the resonance frequency of TE211 on the vertical axis. It looks like the ● mark in the graph in Fig. 7. An example of the resonance frequency change of TE111 is the difference between the frequency marked with ◯ and the frequency marked with ◆ in FIG. An example of the amplitude change at the resonance frequency of TE211 is the difference between the amplitudes marked with ◯ and the amplitudes marked with ◆ in FIG. Similarly, when the case of skim milk powder is obtained, it is as shown by the ▲ mark in FIG. The graph of wheat flour (● mark) and skim milk powder (▲ mark) in FIG. 7 is used as the correlation for substance identification. Prior to the measurement of the object to be inspected, the process until this correlation is obtained is performed in advance.

Next, the tube 61 containing the object to be inspected is installed in the cavity resonator 6, and the network analyzer 3 irradiates a plurality of different electromagnetic waves having a frequency of 2 to 4 GHz to receive the transmitted electromagnetic wave. If the resonance frequency change of the electromagnetic resonance mode TE111 and the amplitude change at the resonance frequency of TE211 are detected by the PC1 and applied to the correlation of the graph of FIG. 7 obtained in advance, the substance can be identified, that is, the example of FIG. Then, it is possible to identify whether it is wheat flour or defatted milk powder. If the same correlation as in FIG. 7 is obtained in advance for other known substances instead of wheat flour and skim milk powder, it is basically possible to identify other unknown substances.

An embodiment of the present invention has been described with reference to the drawings. However, the present invention is not limited to these embodiments. Further, the present invention can be carried out in a mode in which various improvements, modifications and modifications are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

The device / method for identifying a substance using the electromagnetic wave of the present invention is an evaluation device / method capable of non-destructively identifying a substance regardless of the amount of the substance, and is used by public and private analytical institutions, manufacturing industries, and food industry associations. It can be widely used and applied in such cases.

1: Analysis means (personal computer (PC))
2: Cable 3: Electromagnetic wave measuring means (network analyzer)
4, 5: Coaxial cable 6: Cavity resonator 7, 8: Input / output port 61: Container (tube)
62: Substance (sample, non-inspected object)
63, 64: Antenna probe 100: Identification device

Claims (13)

A device for identifying substances using electromagnetic waves,
A cavity resonator that can contain substances and
An electromagnetic wave measuring means for measuring the resonance frequency and amplitude of the transmitted or reflected electromagnetic wave transmitted from the cavity resonator by transmitting electromagnetic waves having a plurality of frequencies to the cavity resonator and receiving the electromagnetic wave.
It is provided with an analysis means for identifying a substance contained in the cavity resonator from the measured resonance frequency change and amplitude change of the electromagnetic wave.
The analysis means is
(I) the detect known amounts resonant frequency change of the measured electromagnetic wave at two different electromagnetic field modes in response to changes in the material in the cavity resonator, the resonance of two different electromagnetic modes Find the correlation of frequency changes,
(Ii) An apparatus for identifying a substance to be inspected by applying a resonance frequency change detected for the substance to be inspected to the corresponding correlation with respect to the known substance. A device for identifying substances using electromagnetic waves,
A cavity resonator that can contain substances and
An electromagnetic wave measuring means for measuring the resonance frequency and amplitude of the transmitted or reflected electromagnetic wave transmitted from the cavity resonator by transmitting electromagnetic waves having a plurality of frequencies to the cavity resonator and receiving the electromagnetic wave.
It is provided with an analysis means for identifying a substance contained in the cavity resonator from the measured resonance frequency change and amplitude change of the electromagnetic wave.
The analysis means is
(I) said detected amplitude variations at a known resonance frequency change and the resonance frequency of the electromagnetic wave in response to changes in the amount measured at two different electromagnetic field modes of a substance in the cavity resonator, the two Find the correlation between the resonance frequency change in different electromagnetic wave modes and the amplitude change at the resonance frequency.
(Ii) An apparatus for identifying a substance to be inspected by applying the resonance frequency change detected for the substance to be inspected and the amplitude change at the resonance frequency to the corresponding correlation with respect to the known substance. A device for identifying substances using electromagnetic waves,
A cavity resonator that can contain substances and
An electromagnetic wave measuring means for measuring the resonance frequency and amplitude of the transmitted or reflected electromagnetic wave transmitted from the cavity resonator by transmitting electromagnetic waves having a plurality of frequencies to the cavity resonator and receiving the electromagnetic wave.
It is provided with an analysis means for identifying a substance contained in the cavity resonator from the measured resonance frequency change and amplitude change of the electromagnetic wave.
The analysis means is
(I) said detected amplitude variations at specific known frequencies of the electromagnetic wave in response to changes in the amount measured at two different electromagnetic field modes of a substance in the cavity resonator, the two different electromagnetic modes Find the correlation of the amplitude change at a specific frequency in
(Ii) An apparatus for identifying a substance to be inspected by applying a change in amplitude at a specific frequency detected for the substance to be inspected to the corresponding correlation for the known substance. The analysis means is
In two different electromagnetic field modes of the cavity resonator, the resonance frequency of the cavity resonator in a state not containing the substance to be inspected and the cavity resonance measured while changing the amount of each of a plurality of known substances. The apparatus according to claim 1, wherein the frequency difference from the resonance frequency of the electromagnetic wave transmitted or reflected from the device is used as the resonance frequency change in the two different electromagnetic field modes to obtain the correlation of the resonance frequency change. The analysis means is
In the first electromagnetic wave mode of the cavity resonator, the resonance frequency of the cavity resonator in a state not containing the substance to be inspected and the cavity resonance measured while changing the amount of each of the plurality of known substances. The frequency difference from the resonance frequency of the electromagnetic wave transmitted or reflected from the vessel and the amplitude at the resonance frequency of the cavity resonator in the second electromagnetic field mode of the cavity resonator without containing the substance to be inspected. , The amplitude difference between the amplitude of the transmitted or reflected electromagnetic wave from the cavity resonator at the resonance frequency and the amplitude at the resonance frequency measured while changing the amount of each of the plurality of known substances. The apparatus according to claim 2 , wherein the correlation between the resonance frequency change and the amplitude change at the resonance frequency is obtained as the amplitude change. The analysis means is
Amplitude of transmitted or reflected electromagnetic waves from the cavity resonator in a state not containing the substance to be inspected when the cavity resonator is irradiated with electromagnetic waves of two different frequencies in different electromagnetic wave modes, and a plurality of known electromagnetic waves. The amplitude difference from the amplitude of the electromagnetic wave transmitted or reflected from the cavity resonator measured while changing the amount of each of the substances is defined as the amplitude change at the specific frequency, and the correlation of the amplitude change at the specific frequency. The device according to claim 3. The device according to claim 1 or 4 , wherein the two different electromagnetic field modes include a TE111 mode and a TE211 mode. The apparatus according to claim 5 , wherein the first electromagnetic field mode includes a TE111 mode, and the second electromagnetic field mode includes a TE211 mode. It is a method of identifying substances using electromagnetic waves.
(A) A step of irradiating a cavity resonator containing an unknown substance with electromagnetic waves having a plurality of frequencies and receiving electromagnetic waves transmitted or reflected.
(B) A step of detecting the resonance frequency of the received electromagnetic wave and
(C) In two different electromagnetic field modes of the cavity resonator, the frequency difference between the resonance frequency of the cavity resonator in a state of not containing the unknown substance obtained in advance and the resonance frequency of the detected electromagnetic wave. And the steps to ask for
(D) A plurality of the two different electromagnetic fields obtained in advance by the steps (a) to (c) while changing the amount of the frequency difference in the two different electromagnetic field modes for each of the plurality of known substances. An identification method comprising the step of identifying the unknown substance by fitting to the correlation of the frequency difference in the field mode. It is a method of identifying substances using electromagnetic waves.
(A) A step of irradiating a cavity resonator containing an unknown substance with two electromagnetic waves of different frequencies in different electromagnetic field modes to receive the transmitted or reflected electromagnetic waves.
(B) A step of detecting the amplitude of the received electromagnetic wave at the resonance frequency, and
(C) said at each of two different frequencies, and amplitudes at the resonant frequency of the cavity resonator in the state without containing the unknown material obtained in advance, the amplitude at the resonant frequency of the detected electromagnetic wave And the step to find the amplitude difference with
(D) A plurality of the two differences obtained in advance by the steps (a) to (c) while changing the amount of the amplitude difference at each of the two different frequencies for each of the plurality of known substances. An identification method comprising the step of identifying the unknown substance by fitting to the correlation of the amplitude difference in frequency. It is a method of identifying substances using electromagnetic waves.
(A) A step of irradiating a cavity resonator containing an unknown substance with electromagnetic waves having a plurality of frequencies and receiving electromagnetic waves transmitted or reflected.
(B) A step of detecting the amplitude of the received electromagnetic wave at the resonance frequency, and
(C) In the first electromagnetic field mode of the cavity resonator, a step of obtaining a frequency difference between the resonance frequency of the cavity resonator in a state of not containing the unknown substance obtained in advance and the resonance frequency of the electromagnetic wave. When,
(D) In the second electromagnetic field mode of the cavity resonator, the amplitude at the resonance frequency of the cavity resonator in a state of not containing the unknown substance obtained in advance and the resonance frequency of the detected electromagnetic wave are used. And the step to find the amplitude difference from the amplitude of
(E) The steps (a) to (a) to change the amount of the frequency difference in the first electromagnetic field mode and the amplitude difference in the second electromagnetic field mode for each of a plurality of known substances. The unknown substance is identified by applying the correlation between the frequency difference in the first electromagnetic field mode and the amplitude difference in the second electromagnetic field mode obtained in advance in (d). Steps to be made, and identification methods including. The method of claim 9 or 10 , wherein the two different electromagnetic field modes include a TE111 mode and a TE211 mode. 11. The method of claim 11 , wherein the first electromagnetic field mode comprises a TE111 mode and the second electromagnetic field mode comprises a TE211 mode.

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