WO2019059038A1

WO2019059038A1 - Heating device

Info

Publication number: WO2019059038A1
Application number: PCT/JP2018/033576
Authority: WO
Inventors: 友彦三谷; 大地西尾
Original assignee: 国立大学法人京都大学
Priority date: 2017-09-21
Filing date: 2018-09-11
Publication date: 2019-03-28

Abstract

This heating device (10) is provided with: a resonator (11) which comprises a planar conductor (112); and a resonator (12) which comprises a planar conductor (122). The planar conductor (112) and the planar conductor (122) are arranged at a distance from each other, and are electromagnetically coupled to each other; and a space (13), in which an article to be heated is arranged, is formed between the planar conductor (112) and the planar conductor (122).

Description

Heating device

The present invention relates to a heating apparatus for heating an object to be heated with an electromagnetic field.

The most common heating device utilizing an electromagnetic field is a microwave oven. Microwave ovens are used in daily life as well as in specialized applications such as chemical experiments. In addition, many heating devices are known which insert an object to be heated into a cavity resonator and heat the object. For example, Patent Document 1 discloses a microwave heating apparatus that heats a material to be treated in a heating chamber by irradiating microwaves generated by a magnetron into the heating chamber. Patent Document 2 discloses a microwave heating apparatus which efficiently heats a heating element in a cavity resonator by arranging the heating element on the antinode of a standing wave generated in the cavity resonator.

Further, as a feeding method using an electromagnetic field, an electromagnetic field coupling type wireless feeding technology as disclosed in Non-Patent

Documents

1 and 2 is known.

JP, 2009-301764, A JP, 2006-140063, A

A conventional heating device using a cavity resonator can basically heat only one object to be heated, and can not heat a plurality of objects to be heated simultaneously. For this reason, a great deal of time will be spent heating the sample, especially in applications of chemical experiments.

On the other hand, a heating device such as a microwave oven can heat a plurality of objects to be heated simultaneously. However, in such a heating device, in order to prevent the electromagnetic waves from leaking and adversely affecting the communication equipment and the human body, it is necessary to surround the irradiation area of the electromagnetic waves with metal.

An object of the present invention is to provide a heating device capable of heating a plurality of objects to be heated simultaneously and also capable of heating without arranging the objects to be heated in a closed space.

A heating apparatus according to the present invention comprises a first resonator having a first planar conductor, and a second resonator having a second planar conductor, wherein the first planar conductor and the second planar conductor Are spaced apart from each other, electromagnetically coupled to each other, and a space for disposing an object to be heated is formed between the first planar conductor and the second planar conductor.

In this configuration, a plurality of objects to be heated can be heated simultaneously. This results in a significant reduction of the experimental time, in particular in applications of chemical experiments. Further, since the leakage of the electromagnetic field to the outside of the heating device is small, the object to be heated can be heated without arranging the object to be heated in the closed space.

In addition, the first resonator has a first ground conductor facing the first planar conductor, and the second resonator has a second ground conductor facing the second planar conductor. The first ground conductor and the second ground conductor may face each other. This configuration can realize the heating device easily.

In the direction from the first ground conductor to the second ground conductor, the first planar conductor is disposed between the first ground conductor and the second ground conductor, and the second planar conductor is It may be disposed between the first planar conductor and the second ground conductor.

Further, the first planar conductor and the second planar conductor may face each other.

Further, a plurality of the second resonators are provided, and when viewed in plan from the direction of the normal of the main surface of the first planar conductor, the position of the second planar conductor of the plurality of second resonators is the second It may be offset from the position of the one-sided conductor. In this configuration, a plurality of the same objects to be heated can be heated simultaneously and uniformly.

Further, a plurality of the first resonators and the second resonators are provided, and the first planar conductors of the plurality of first resonators are electromagnetically coupled to each other, and the second planar shapes of the plurality of second resonators are formed. The conductors may be electromagnetically coupled to one another. Even with this configuration, a plurality of the same objects to be heated can be heated simultaneously and uniformly.

Further, the first planar conductor may be connected to a feed line, and the second planar conductor may be open. This configuration further improves the heating characteristics of the heating device.

The first resonator and the second resonator are, for example, half-wave resonators. In this configuration, the heating device can be miniaturized.

According to the present invention, a plurality of objects to be heated can be simultaneously heated, and can be heated without arranging the objects to be heated in a closed space.

FIG. 1 is a perspective view of a heating device 10 according to a first embodiment. FIG. 2A is a plan view of the heating device 10. FIG. 2B is a cross-sectional view of the heating device 10 taken along the line A1-A1. FIG. 3 is a perspective view of the heating device 10 in which the sample 22 is disposed. FIG. 4A is a plan view of the heating device 10 in which the sample 22 is disposed. FIG. 4B is an A2-A2 cross-sectional view of the heating device 10 in which the sample 22 is disposed. FIG. 5A is a circuit diagram showing an equivalent circuit 30 of the heating device 10. FIG. 5B is a circuit diagram showing an equivalent circuit 40 obtained by modifying the equivalent circuit 30. As shown in FIG. FIG. 5C is a circuit diagram showing the input impedance Zi as viewed from the terminals P1 and P2 to the equivalent circuit 40 side. FIG. 6A shows a simulation result of the absolute value of the S parameter S11. FIG. 6B shows a simulation result of the absolute value of the S parameter S21. FIG. 7A is a perspective view showing a simulation result of the electric field distribution between the

resonators

11 and 12. FIG. 7B is a cross-sectional view showing a simulation result of the pointing vector between the

resonators

11 and 12. FIG. 8 is a diagram showing simulation results of the power characteristics of the heating device 10. As shown in FIG. FIG. 9 is a graph showing the temperature characteristics of the real part εr ′ of the complex relative dielectric constant of pure water and the dielectric loss tangent tanδ. FIGS. 10A and 10B show S-parameters when the arrangement relationship between the sample 22 and the

dielectric substrates

111 and 121 is changed as shown in FIGS. 12A and 12B. It is a figure which shows the simulation result of the absolute value of S11. 11 (A) and 11 (B) show S-parameters when the positional relationship between the sample 22 and the

dielectric substrates

111 and 121 is changed as shown in FIGS. 12 (A) and 12 (B). It is a figure which shows the simulation result of the absolute value of S11. FIG. 12A is a plan view for explaining the arrangement of the sample 22 and the

dielectric substrates

111 and 121. FIG. 12B is a side view for explaining the arrangement relationship between the sample 22 and the

dielectric substrates

111 and 121. FIG. 13A shows a simulation result of the electric field distribution at a position 100 mm away from the heating device 10. FIG. 13B is a view showing a simulation result of the magnetic field distribution at a position 100 mm away from the heating device 10. FIG. 14A is a plan view of a heating device 50 according to the second embodiment. FIG. 14B is a cross-sectional view of the heating device 50 taken along the line BB. FIG. 15 is a diagram showing simulation results of absorbed power of the sample 22 in the

heating devices

10 and 50. As shown in FIG. FIG. 16A is a diagram showing an example of an experimental result of a time change of the temperature of the sample 22 when the sample 22 is heated by the

heating devices

10 and 50. As shown in FIG. FIG. 16B is a diagram showing a time change of the estimated absorbed power of the sample 22 estimated from the time change of the temperature of the sample 22 shown in FIG. 16A. FIG. 17A is a cross-sectional view showing the simulation result of the electric field distribution in the inside of the sample 22 at the time of heating by the heating device 10. FIG. 17B is a cross-sectional view showing a simulation result of the electric field distribution in the sample 22 at the time of heating by the heating device 50. FIG. 18 is a perspective view of a heating device 60 according to the third embodiment. FIG. 19A is a plan view of the heating device 60. FIG. FIG. 19B is a cross-sectional view of the heating device 60 taken along the line C1-C1. FIG. 20 is a perspective view of the heating device 60 in which the

samples

22A and 22B are disposed. FIG. 21A is a plan view of the heating device 60 in which the

samples

22A and 22B are disposed. FIG. 21B is a C2-C2 cross-sectional view of the heating device 60 in which the

samples

22A and 22B are disposed. FIG. 22A is a plan view of a heating device 70 according to a modification of the third embodiment. FIG. 22B is a cross-sectional view of the heating device 70 taken along the line DD. FIG. 23 is a view showing an example of an experimental result of a temporal change in temperature of the

samples

22A and 22B when the

samples

22A and 22B are heated by the

heating devices

60 and 70. FIG. 24 is a perspective view of a heating device 80 according to the fourth embodiment. FIG. 25A is a plan view of the heating device 80. FIG. FIG. 25B is a cross-sectional view of the heating device 80 taken along line E1-E1. FIG. 26 is a perspective view of the heating device 80 in which the

samples

22A and 22B are disposed. FIG. 27A is a plan view of the heating device 80 in which the

samples

22A and 22B are disposed. FIG. 27B is an E2-E2 cross-sectional view of the heating device 80 in which the

samples

22A and 22B are disposed. FIG. 28 is a diagram showing simulation results of power characteristics of the heating device 80. As shown in FIG. FIG. 29 is a view showing an example of the experimental results of the time change of the temperature and the reflected power of the

samples

22A and 22B when the

samples

22A and 22B are heated by the heating device 80.

Hereinafter, some specific examples will be described with reference to the drawings to show a plurality of modes for carrying out the present invention. In the second and subsequent embodiments, descriptions of matters in common with the first embodiment will be omitted, and different points will be described. In particular, the same operation and effect by the same configuration will not be sequentially referred to in each embodiment.

First Embodiment
FIG. 1 is a perspective view of a heating device 10 according to a first embodiment. FIG. 2A is a plan view of the heating device 10. FIG. 2B is a cross-sectional view of the heating device 10 taken along the line A1-A1. The

coaxial cables

14 and 15 are not shown in FIGS. 1 and 2A.

The heating device 10 includes square

flat resonators

11 and 12. The resonator 11 is an example of the "first resonator" in the present invention. The resonator 12 is an example of the "second resonator" in the present invention. The

resonators

11 and 12 are half-wave resonators having a microstrip structure. The resonator 11 and the resonator 12 have substantially the same structure. The

resonators

11 and 12 are disposed to face each other at a predetermined distance. The

coaxial cables

14 and 15 are connected to the

resonators

11 and 12, respectively. When the high frequency power is supplied to the heating device 10, the resonator 11 and the resonator 12 are electromagnetically coupled to each other.

The resonator 11 has a dielectric substrate 111, a plane conductor 112 and a ground conductor 113. The planar conductor 112 is an example of the "first planar conductor" in the present invention. The ground conductor 113 is an example of the “first ground conductor” in the present invention.

The dielectric substrate 111 and the ground conductor 113 are each in the form of a rectangular plate. The plane conductor 112 is rectangular flat. The longitudinal dimension of the planar conductor 112 is approximately equal to one half of the wavelength in the high frequency dielectric substrate 111 used for the heating device 10. The flat conductor 112 is formed substantially at the center of one main surface of the dielectric substrate 111. The ground conductor 113 is formed on substantially the entire surface of the other main surface of the dielectric substrate 111. The flat conductor 112 and the ground conductor 113 are opposed to each other via the dielectric substrate 111.

An inner conductor 141 of the coaxial cable 14 is connected to the plane conductor 112. The inner conductor 141 is an example of the “feed line” in the present invention. The inner conductor 141 extends through the opening 114 formed in the ground conductor 113 and then through the dielectric substrate 111 to the planar conductor 112. The connection portion between the flat conductor 112 and the inner conductor 141 constitutes an input end 115. The input end 115 is separated from the center point of the plane conductor 112 by a distance Dci in the longitudinal direction of the plane conductor 112 in plan view in the direction of the normal to the main surface of the plane conductor 112. The outer conductor 142 of the coaxial cable 14 is connected to the ground conductor 113. The flat conductor 112 is connected to a high frequency power source (not shown) via the inner conductor 141 of the coaxial cable 14. The high frequency used for the heating device 10 is, for example, microwaves in the 2.45 GHz band, but is not limited thereto. The ground conductor 113 is connected to the outer conductor 142 of the coaxial cable 14. At the input end 115 side of the heating device 10, impedance matching is performed such that the input impedance seen from the input end 115 to the heating device 10 side is, for example, 50 Ω.

The resonator 12 has a dielectric substrate 121, a plane conductor 122 and a ground conductor 123. The planar conductor 122 is an example of the "second planar conductor" in the present invention. The ground conductor 123 is an example of the “second ground conductor” in the present invention.

The dielectric substrate 121 and the ground conductor 123 are each in the form of a rectangular flat plate. The flat conductor 122 is rectangular flat. The longitudinal dimension of the planar conductor 122 is approximately equal to one half of the wavelength in the high frequency dielectric substrate 121 used for the heating device 10. The flat conductor 122 is formed substantially at the center of one main surface of the dielectric substrate 121. The ground conductor 123 is formed on substantially the entire surface of the other main surface of the dielectric substrate 121. The flat conductor 122 and the ground conductor 123 are opposed to each other via the dielectric substrate 121.

The inner conductor 151 of the coaxial cable 15 is connected to the plane conductor 122. The inner conductor 151 of the coaxial cable 15 extends through the opening 124 formed in the ground conductor 123 and then through the dielectric substrate 121 to the planar conductor 122. The connection portion between the plane conductor 122 and the inner conductor 151 constitutes an output end 125. The output end 125 is separated from the center point of the plane conductor 122 by a distance Dcо in the longitudinal direction of the plane conductor 122 in plan view in the direction of the normal to the main surface of the plane conductor 122. An outer conductor 152 of the coaxial cable 15 is connected to the ground conductor 123. The plane conductor 122 is connected to a load (not shown) (not shown) via the inner conductor 151 of the coaxial cable 15. The ground conductor 123 is connected to the outer conductor 152 of the coaxial cable 15. At the output end 125 side of the heating device 10, impedance matching is performed such that the input impedance seen from the output end 125 to the heating device 10 side is, for example, 50Ω.

The main surface of the dielectric substrate 111 on which the flat conductor 112 is formed and the main surface of the dielectric substrate 121 on which the flat conductor 122 is formed are opposed to each other at a predetermined distance. The distance between dielectric substrate 111 and dielectric substrate 121 may be secured by a spacer (not shown) or may be secured by a support member (not shown) for supporting

dielectric substrates

111 and 121. . The plane conductor 112 and the plane conductor 122 are arranged to face each other at a predetermined distance. The planar conductor 112 and the planar conductor 122 substantially coincide with each other in plan view from the direction of the normal to the main surface of the planar conductor 112 (almost completely overlap). A space 13 for disposing an object to be heated is formed between the plane conductor 112 and the plane conductor 122. When high frequency power is supplied to the heating device 10, the planar conductor 112 of the resonator 11 and the planar conductor 122 of the resonator 12 are electromagnetically coupled. In this electromagnetic coupling, the contribution of the electric field coupling is larger than the contribution of the magnetic field coupling.

FIG. 3 is a perspective view of the heating device 10 in which the sample 22 is disposed. FIG. 4A is a plan view of the heating device 10 in which the sample 22 is disposed. FIG. 4B is an A2-A2 cross-sectional view of the heating device 10 in which the sample 22 is disposed. In FIG. 3 and FIG. 4 (A), illustration of the

coaxial cables

14 and 15 is omitted. The sample 22 is an example of the "object to be heated" of the present invention. The sample 22 is, for example, water or an organic solvent. The sample 22 in the test tube 21 is disposed in the space 13 between the plane conductor 112 and the plane conductor 122 when heated. The test tube 21 is supported by a support member (not shown). Preferably, at least a portion of the sample 22 is disposed near the longitudinal ends of the planar conductors 112,122.

A plurality of objects to be heated may be disposed in the space 13. For example, one object to be heated may be disposed at one end in the longitudinal direction of the

planar conductors

112 and 122, and another object to be heated may be disposed at the other end in the longitudinal direction of the

planar conductors

112 and 122. Also, a plurality of objects to be heated may be disposed in the space 13 along the short direction of the

planar conductors

112 and 122.

In the heating device 10, when high frequency power is supplied from the high frequency power source (not shown) to the input end 115 via the inner conductor 141 of the coaxial cable 14, the flat conductor 112 of the resonator 11 and the flat conductor 122 of the resonator 12 And are electromagnetically coupled. The sample 22 is heated by the electromagnetic field that contributes to the electromagnetic field coupling and is generated in the space 13 between the planar conductor 112 and the planar conductor 122.

FIG. 5A is a circuit diagram showing an equivalent circuit 30 of the heating device 10. In the equivalent circuit 30, the electromagnetic field coupling between the

resonators

11 and 12 is approximated by electric field coupling. Further, in the equivalent circuit 30, the influence of the object to be heated is not considered. The equivalent circuit 30 includes

resonant circuits

31 and 32. The inductors constituting the

resonant circuits

31 and 32 both have an inductance L. Each capacitor constituting the

resonant circuits

31 and 32 has a capacitance C. The capacitors constituting the

resonant circuits

31 and 32 are electrically coupled to each other by mutual capacitance Cm. The resonant circuit 31 is connected to a high frequency power supply (not shown) by the terminals P1 and P2. The resonant circuit 32 is connected to a load having an impedance Z. The resonant circuit 31 is an equivalent circuit of the resonator 11 of the heating device 10. The resonant circuit 32 is an equivalent circuit of the resonator 12 of the heating device 10.

FIG. 5B is a circuit diagram showing an equivalent circuit 40 obtained by modifying the equivalent circuit 30. As shown in FIG. The equivalent circuit 40 includes

resonant circuits

41 and 42. Each of the inductors constituting the

resonant circuits

41 and 42 has an inductance L. Each capacitor constituting the

resonant circuits

41 and 42 has a capacitance C-Cm. The resonant circuit 41 and the resonant circuit 42 are connected via a capacitor having a capacitance Cm.

FIG. 5C is a circuit diagram showing the input impedance Zi as viewed from the terminals P1 and P2 to the equivalent circuit 40 side. The input impedance Zi at the frequency ω = 1 / = 1LC is 1 / (ωCm) ² Z. Thus, the influence of the capacitors of the

resonant circuits

31 and 32 on the input impedance Zi disappears due to the resonance.

Next, the conditions of the simulation or experiment from which the results of the simulation or experiment of the heating device 10 described below were obtained will be described. However, with regard to the results of simulation or experiment of the heating device 10 described below, when simulation or experiment is performed under conditions different from the conditions described here, the applied conditions will be described each time. Hereinafter, the conditions described here will be referred to as basic conditions.

The setting parameters of the heating device 10 as shown in FIG. 2 (A) and FIG. 2 (B) were set as follows.

Dimension in the x-axis direction of the

dielectric substrates

111 and 121 Dsx = 100 mm
Dimension in the y-axis direction of the

dielectric substrates

111 and 121 Dsy = 100 mm
Dimension in the z-axis direction of the

dielectric substrates

111 and 121 Dsz = 0.8 mm
Dimension in the x-axis direction of the

plane conductor

112, 122 Dcx = 10 mm
Dimension of

planar conductor

112, 122 in the y-axis direction Dcy = 38.5 mm
Distance between dielectric substrate 111 and dielectric substrate 121 h = 20 mm
Distance between the center point of the plane conductor 112 and the input end 115 Dci = 8 mm
Distance between center point of flat conductor 122 and output end 125 Dcо = 8 mm
Real part of complex relative permittivity of

dielectric substrates

111 and 121 2.53
Used frequency 2.45 GHz
Here, the short direction of the plane conductor 112 is taken as the x-axis direction, the longitudinal direction of the plane conductor 112 is taken as the y-axis direction, and the direction normal to the main surface of the plane conductor 112 is taken as the z-axis direction.

Further, as shown in FIG. 3, FIG. 4 (A) and FIG. 4 (B), the sample 22 in the test tube 21 was placed in the space 13. The inner diameter Ra of the test tube 21 was 11.8 mm, the outer diameter Rb of the test tube 21 was 15 mm, and the sample 22 was pure water of 4.3 mL.

FIG. 6A shows a simulation result of the absolute value of the S parameter S11. FIG. 6B shows a simulation result of the absolute value of the S parameter S21. Here, the distance Dci was changed to various values, and the distance Dcо was changed to the same value as the distance Dci. The other conditions were set in the same manner as the above basic conditions. Further, the S parameter was calculated with the input end 115 side as the first terminal pair side and the output end 125 side as the second terminal pair side.

As shown in FIGS. 6A and 6B, bimodality appears in the absolute values of the S parameters S11 and S21. From this, it can be seen that the plane conductor 112 of the resonator 11 and the plane conductor 122 of the resonator 12 are electromagnetically coupled.

Also, at 2.45 GHz, which is the operating frequency, as the distance Dci becomes longer, the absolute value of the S parameter S11 tends to be smaller, and the absolute value of the S parameter S21 tends to be larger. On the other hand, when the distance Dci is 10 mm, bimodality does not appear in the absolute value of the S parameter S11. Therefore, it is preferable to set the distances Dci and Dcо to 8 mm.

FIG. 7A is a perspective view showing a simulation result of the electric field distribution between the

resonators

11 and 12. Here, the test tube 21 and the sample 22 were not disposed in the space 13 of the heating device 10. The other conditions were set in the same manner as the above basic conditions. As shown in FIG. 7A, the electric field becomes large near the ends in the longitudinal direction of the

planar conductors

112 and 122. As shown in FIG. 7B, the energy flow increases near the ends in the longitudinal direction of the

planar conductors

112 and 122. For this reason, as described above, it is preferable that at least a part of the object to be heated be disposed near the ends in the longitudinal direction of the

planar conductors

112 and 122.

FIG. 8 is a diagram showing simulation results of the power characteristics of the heating device 10. As shown in FIG. Here, real part εr ′ of complex relative dielectric constant of pure water and dielectric loss tangent tanδ shown in FIG. 9 were used. The other conditions were set in the same manner as the above basic conditions. In FIG. 8, “absorbed power of sample” is the power absorbed by the sample 22. “Reflected power” is the power reflected at the input end 115. “Transparent power” is power transmitted from the input end 115 side to the output end 125 side. “Leakage power” is power that leaks from the heating device 10. The “absorbed power of the substrate or the like” is the power absorbed by the

dielectric substrates

111 and 121 and the test tube 21. In FIG. 8, the absorbed power of the sample, the reflected power, the transmitted power, the leaked power, and the absorbed power of the substrate and the like are represented as a percentage of the input power input to the input terminal 115.

When the temperature of the sample 22 is 20 ° C., about 70% of the input power is absorbed by the sample 22. As the temperature of the sample 22 rises, the absorbed power of the sample 22 decreases. This drop occurs because when the temperature of the sample 22 changes, the dielectric properties of the sample 22 change, and as a result, the state of impedance matching changes. Also, regardless of the temperature of the sample 22, the ratio of the leakage power is 20% or less of the input power. From this result, it can be understood that the electromagnetic field leaking to the outside of the heating device 10 at the time of heating is small.

10 (A), 10 (B), 11 (A) and 11 (B) show samples 22 and

dielectric substrates

111 and 121 as shown in FIGS. 12 (A) and 12 (B). When the arrangement relationship of is changed, it is a figure which shows the simulation result of the absolute value of S parameter S11. Here, the temperature of the sample 22 was set to 20.degree. In FIG. 11A, the distance h between the dielectric substrate 111 and the dielectric substrate 121 is changed. The other conditions were set in the same manner as the above basic conditions. Further, the S parameter was calculated with the input end 115 side as the first terminal pair side and the output end 125 side as the second terminal pair side.

FIG. 12A is a plan view for explaining the arrangement of the sample 22 and the

dielectric substrates

111 and 121. In FIGS. 12A and 12B, the

ground conductors

113 and 123 and the

coaxial cables

14 and 15 are not shown.

FIG. 10A shows an arrangement in which the sample 22 is rotated by the angle θx around the x axis from the arrangement of the reference, and an arrangement in which the sample 22 is rotated by the angle θz around the z axis from the arrangement of the reference. It shows the absolute value. Here, as shown in FIGS. 12A and 12B, it corresponds to the center point of the plane conductor 122 when viewed from the direction of the normal to the main surface of the plane conductor 122, and the plane conductor 112 and the plane The origin O of the coordinate axis is defined to be equally spaced from the conductor 122. As shown in FIG. 10A, the absolute value of the S parameter S11 in the arrangement in which the sample 22 is rotated about the z axis hardly changes from the S parameter S11 in the reference arrangement. On the other hand, the absolute value of the S parameter S11 in the arrangement in which the sample 22 is rotated around the x axis is different from the S parameter S11 in the reference arrangement.

FIG. 10B shows an arrangement in which the sample 22 is displaced by the distance Wx in the x-axis direction from the arrangement of the reference, an arrangement in which the sample 22 is moved by the distance Wy in the y-axis direction from the arrangement of the reference, and Shows the absolute value of the S parameter S11 in the arrangement in which the distance Wz is parallel moved in the z-axis direction. As shown in FIG. 10B, the absolute value of the S parameter S11 in the arrangement in which the sample 22 is translated in the x-axis or y-axis direction hardly changes from the absolute value of the S parameter S11 in the reference arrangement. On the other hand, the absolute value of the S parameter S11 in the arrangement in which the sample 22 is translated in the z-axis direction is changed from the absolute value of the S parameter S11 in the reference arrangement.

FIG. 11A shows the absolute value of the S parameter S11 when the distance h between the dielectric substrate 111 and the dielectric substrate 121 is changed. As shown in FIG. 11A, when the distance h changes from the reference value, the absolute value of the S parameter S11 changes.

FIG. 11B shows the absolute value of the S parameter S11 in the arrangement in which the dielectric substrate 121 is moved in the x-axis direction by distance Subx and in the arrangement in which the dielectric substrate 121 is moved in the y-axis direction by distance Suby. ing. As shown in FIG. 11B, the absolute value of the S parameter S11 in the arrangement in which the dielectric substrate 121 is moved in parallel in the x-axis and y-axis directions is almost different from the absolute value of the S parameter S11 in the reference arrangement. Absent.

As shown in FIGS. 10 (A), 10 (B), 11 (A) and 11 (B), the absolute value of the S parameter S11 is x of the arrangement of the sample 22 and the

dielectric substrates

111, 121. Although hardly affected by the deviation in the y-axis direction, it is affected by the deviation in the z-axis direction of the arrangement of the sample 22 and the

dielectric substrates

111 and 121. This occurs because the impedance matching state changes as the sample 22 approaches the

planar conductor

112 or 122. For this reason, it is preferable that the support member which supports a to-be-heated material at the time of heating is what can arrange a to-be-heated material correctly in z axial direction.

FIG. 13A shows a simulation result of the electric field distribution at a position 100 mm away from the heating device 10. FIG. 13B is a view showing a simulation result of the magnetic field distribution at a position 100 mm away from the heating device 10. Here, an input power of 30 W was input to the heating device 10, and the temperature of the sample 22 was set to 80.degree. The other conditions were set in the same manner as the above basic conditions.

As shown in FIGS. 13A and 13B, at a position 100 mm away from the heating device 10, the magnitude of the electric field is 137 V / m or less and the magnitude of the magnetic field is 0.365 A / m or less is there. Therefore, the heating device 10 satisfies the management guideline defined in the radio wave protection guideline when the input power is 30 W or less.

In the first embodiment, the resonator 11 and the resonator 12 are disposed to face each other, the resonator 11 and the resonator 12 are electromagnetically coupled, and then, between the resonator 11 and the resonator 12 Place the object to be heated. Thus, the object to be heated can be heated by the electromagnetic field.

Further, by arranging a plurality of objects to be heated between the resonator 11 and the resonator 12, it is possible to heat a plurality of objects to be heated simultaneously. This results in a significant reduction of the experimental time, in particular in applications of chemical experiments. Thus, the heating device 10 is particularly effective for use in chemical experiments, and is expected to be used as a device for simultaneously heating a plurality of small amounts of objects to be heated.

Further, since the leakage of the electromagnetic field to the outside of the heating device 10 is small, the object to be heated can be heated without arranging the object to be heated in the closed space. Therefore, for example, by sequentially passing the object to be heated between the

resonators

11 and 12, it is possible to continuously heat the plurality of objects to be heated. Thus, the heating device 10 is useful for flow applications. Further, even when the object to be heated is larger than the space 13 between the planar conductor 112 and the planar conductor 122, by arranging a part of the object to be heated between the planar conductor 112 and the planar conductor 122 Part of it can be heated.

In addition, in the electromagnetic field coupling between the resonator 11 and the resonator 12, the contribution of the electric field coupling is large. Therefore, when the object to be heated is a dielectric, the efficiency of power absorption by the object to be heated is high. Therefore, dielectrics such as water and organic solvents can be heated with high power efficiency.

Second Embodiment
FIG. 14A is a plan view of a heating device 50 according to the second embodiment. FIG. 14B is a cross-sectional view of the heating device 50 taken along the line BB. In the heating device 50, the inner conductor of the coaxial cable is not connected to the plane conductor 122. That is, the flat conductor 122 is open.

FIG. 15 is a diagram showing simulation results of absorbed power of the sample 22 in the

heating devices

10 and 50. As shown in FIG. Here, real part εr ′ of complex relative dielectric constant of pure water and dielectric loss tangent tanδ shown in FIG. 9 were used. The other conditions were set in the same manner as the above basic conditions. In FIG. 15, the absorbed power of the sample 22 is expressed as a ratio to the input power input to the input end 115. In the heating device 50, the ratio of the absorbed power absorbed by the sample 22 is improved compared to the heating device 10.

FIG. 16A is a diagram showing an example of an experimental result of a time change of the temperature of the sample 22 when the sample 22 is heated by the

heating devices

10 and 50. As shown in FIG. Here, the input power input to the

heating devices

10 and 50 was set to 10 W. The other conditions were set in the same manner as the above basic conditions. The heating device 50 has improved heating characteristics as compared to the heating device 10. Further, in the heating device 50, the temperature of the sample 22 rises to 80 ° C. or more (a temperature difference of 55 K or more from the atmospheric temperature) in 5 minutes.

FIG. 16B is a diagram showing a time change of the estimated absorbed power of the sample 22 estimated from the time change of the temperature of the sample 22 shown in FIG. 16A. Here, the estimated absorbed power of the sample 22 was calculated using Pest = mc (dT / dt) + hS (T−T ₀ ) + εσsS (T ⁴ −T ₀ ⁴ ). Each variable or constant of the above equation is defined as follows.

Estimated absorbed power Pest
Sample temperature T
Sample mass m = 4.3 g
Sample specific heat c = 4.17 J / g / K
Sample surface area S = 1.74 × 10 ^-3 m ²
Heat transfer coefficient h = 4.6 W / m ² / K
Ambient temperature T ₀ = 300 K
Stephan-Boltzmann constant σs = 5.67 × 10 ^-8 W / m ² / K ⁴
Radiation coefficient ε = 0.96
Further, in the above equation, heat dissipation and heat transfer from the test tube 21 are not taken into consideration for the sake of simplicity.

In the heating device 50, when the temperature of the sample 22 is low, about 90% of the input power is absorbed by the sample 22. Further, it can also be seen from the results shown in FIG. 16B that the heating device 50 has improved heating characteristics as compared to the heating device 10. Although some errors occur between the simulation result shown in FIG. 15 and the experimental result shown in FIG. 16 (B), these results show the same tendency.

FIG. 17A is a cross-sectional view showing the simulation result of the electric field distribution in the inside of the sample 22 at the time of heating by the heating device 10. FIG. 17B is a cross-sectional view showing a simulation result of the electric field distribution in the sample 22 at the time of heating by the heating device 50. As shown in FIG. Here, the temperature of the sample 22 was set to 25 ° C. The other conditions were set in the same manner as the above basic conditions. FIGS. 17A and 17B show the electric field distribution when the amplitude of the electric field inside the sample 22 is maximized.

As shown in FIG. 17A, even when the output end 125 is impedance-matched, approximately 10% of the reflection from the output end 125 toward the sample 22 occurs, so a standing wave is generated. As shown in FIG. 17 (B), when the planar conductor 122 is open, a larger standing wave stands up because there is no transmitted power. This tendency contributes to the increase in the heating efficiency of the heating device 50.

As described above, in the heating device 50 according to the second embodiment, the heating characteristic is further improved by opening the planar conductor 122.

Third Embodiment
FIG. 18 is a perspective view of a heating device 60 according to the third embodiment. FIG. 19A is a plan view of the heating device 60. FIG. FIG. 19B is a cross-sectional view of the heating device 60 taken along the line C1-C1.

The heating device 60 includes

resonators

61A, 61B, 61C, 62A, 62B, 62C. The

resonators

61A, 61B, 61C, 62A, 62B, 62C are half-wave resonators having a microstrip structure. The resonator 61A and the resonator 62A are disposed to face each other at a predetermined distance. The resonator 61B and the resonator 62B are arranged to face each other at a predetermined distance. The resonator 61C and the resonator 62C are disposed to face each other at a predetermined distance. That is, the heating device 60 is provided with three pairs of resonators. Note that three or more pairs of resonators may be provided.

The heating device 60 includes a dielectric substrate 111,

planar conductors

112A, 112B and 112C, and a ground conductor 113. The

resonators

61A, 61B, and 61C are formed by

planar conductors

112A, 112B, and 112C facing the ground conductor 113 via the dielectric substrate 111, respectively. The

resonators

61A, 61B, and 61C share the dielectric substrate 111 and the ground conductor 113.

The

planar conductors

112A, 112B, and 112C are rectangular flat plates, and have substantially the same shape. The

plane conductors

112A, 112B, and 112C are formed on one main surface of the dielectric substrate 111, and the ground conductor 113 is formed on the other main surface of the dielectric substrate 111. The planar conductor 112 </ b> C is disposed substantially at the center of the main surface of the dielectric substrate 111. The plane conductor 112A is disposed at a predetermined interval on one side in the width direction of the plane conductor 112C, and the plane conductor 112B is disposed at a predetermined interval on the other side in the width direction of the plane conductor 112C. The distance between planar conductor 112A and planar conductor 112C is approximately equal to the distance between planar conductor 112B and planar conductor 112C. In other words, the

planar conductors

112A, 112B, and 112C are aligned along the short direction of the planar conductor 112C. The inner conductor 141 of the coaxial cable 14 is connected to the plane conductor 112C. A connection portion between the flat conductor 112C and the inner conductor 141 constitutes an input end 115. Note that a plurality of input terminals may be provided. For example, an input end may be provided on each of the

planar conductors

112A, 112B, and 112C.

The heating device 60 includes a dielectric substrate 121,

planar conductors

122A, 122B and 122C, and a ground conductor 123. The

resonators

62A, 62B and 62C are formed by the

planar conductors

122A, 122B and 122C facing the ground conductor 123 with the dielectric substrate 121 interposed therebetween. The

resonators

62A, 62B, 62C share the dielectric substrate 121 and the ground conductor 123.

The

planar conductors

122A, 122B, and 122C are rectangular flat plates, and have substantially the same shape. The

plane conductors

122A, 122B and 122C are formed on one main surface of the dielectric substrate 121, and the ground conductor 123 is formed on the other main surface of the dielectric substrate 121. The flat conductor 122 </ b> C is disposed substantially at the center of the main surface of the dielectric substrate 121. The plane conductor 122A is disposed at a predetermined interval on one side in the width direction of the plane conductor 122C, and the plane conductor 122B is disposed at a predetermined interval on the other side in the width direction of the plane conductor 122C. The distance between the plane conductor 122A and the plane conductor 122C is approximately equal to the distance between the plane conductor 122B and the plane conductor 122C. In other words, the

planar conductors

122A, 122B, and 122C are aligned along the short direction of the planar conductor 122C. The inner conductor 151 of the coaxial cable 15 is connected to the plane conductor 122C. The connection portion between the flat conductor 122C and the inner conductor 151 constitutes an output end 125. Note that a plurality of output terminals may be provided. For example, an output end may be provided to each of the

plane conductors

122A, 122B, and 122C in response to the input end being provided to each of the

plane conductors

112A, 112B, and 112C.

The plane conductor 112A and the plane conductor 122A are arranged to face each other at a predetermined interval. A space 13A for disposing an object to be heated is formed between the plane conductor 112A and the plane conductor 122A. The plane conductor 112B and the plane conductor 122B are arranged to face each other at a predetermined interval. A space 13B for disposing an object to be heated is formed between the plane conductor 112B and the plane conductor 122B. The plane conductor 112C and the plane conductor 122C are arranged to face each other at a predetermined interval. When high frequency power is supplied to the heating device 60, the

planar conductors

112A, 112B, 112C, 122A, 122B, and 122C of the

resonators

61A, 61B, 61C, 62A, 62B, and 62C are electromagnetically coupled to each other.

FIG. 20 is a perspective view of the heating device 60 in which the

samples

22A and 22B are disposed. The sample 22A in the test tube 21A is disposed in the space 13A between the planar conductor 112A and the planar conductor 122A when heated. The sample 22B in the test tube 21B is disposed in the space 13B between the planar conductor 112B and the planar conductor 122B when heated. The

test tubes

21A and 21B are supported by support members (not shown).

In the heating device 60, when high frequency power is supplied from the high frequency power source (not shown) to the input end 115, the

planar conductors

112A, 112B, 112C, 122A, 122B of the

resonators

61A, 61B, 61C, 62A, 62B, 62C. , 122C are electromagnetically coupled to each other. The sample 22A is heated by the electromagnetic field generated in the space 13A between the plane conductor 112A and the plane conductor 122A. The sample 22B is heated by the electromagnetic field generated in the space 13B between the plane conductor 112B and the plane conductor 122B.

FIG. 22A is a plan view of a heating device 70 according to a modification of the third embodiment. FIG. 22B is a cross-sectional view of the heating device 70 taken along the line DD. In heating device 70, the inner conductor of the coaxial cable is not connected to flat conductor 122C, and flat conductor 122C is open. The other configuration of the heating device 70 is the same as the configuration of the heating device 60.

FIG. 23 is a view showing an example of an experimental result of a temporal change in temperature of the

samples

22A and 22B when the

samples

22A and 22B are heated by the

heating devices

60 and 70. Here, the input power to be input to the

heating devices

60 and 70 was set to 10 W. The other conditions were set in the same manner as the above basic conditions. As shown in FIG. 23, in either of the

heating devices

60 and 70, the

samples

22A and 22B are substantially uniformly heated to each other.

In the third embodiment, due to the symmetry of the structure of the heating device 60, the distributions of electromagnetic fields generated in the

spaces

13A and 13B are substantially the same. Therefore, the same objects to be heated disposed in the

spaces

13A and 13B absorb substantially the same power. Therefore, a plurality of the same objects to be heated can be simultaneously and uniformly heated.

Fourth Embodiment
FIG. 24 is a perspective view of a heating device 80 according to the fourth embodiment. FIG. 25A is a plan view of the heating device 80. FIG. FIG. 25B is a cross-sectional view of the heating device 80 taken along line E1-E1.

The heating device 80 is substantially the same as the heating device 70 according to the modification of the second embodiment except for the

flat conductors

112A, 112B and 122C. The heating device 80 includes

resonators

81, 82A, 82B. The

resonators

81, 82A, 82B are half-wave resonators having a microstrip structure. The resonator 81 and the

resonators

82A and 82B are arranged at a predetermined interval in the direction of the normal to the main surface of the resonator 81. The

resonators

82A and 82B are arranged at predetermined intervals in the direction parallel to the main surface of the resonator 81. The resonator 81 is disposed between the resonator 82A and the resonator 82B in a plan view from the direction of the normal to the main surface of the resonator 81.

Heating device 80 includes a dielectric substrate 111, a foil-like planar conductor 112 formed on one main surface of dielectric substrate 111, and a foil-like ground conductor 113 formed on the other main surface of dielectric substrate 111. Equipped with The resonator 81 is formed by the planar conductor 112 facing the ground conductor 113 via the dielectric substrate 111. A connection portion between the flat conductor 112 and the inner conductor 141 of the coaxial cable 14 constitutes an input end 115.

Heating device 80 includes dielectric substrate 121, foil-like

planar conductors

122A and 122B formed on one principal surface of dielectric substrate 121, and a foil-like ground conductor formed on the other principal surface of dielectric substrate 121. And 123. The

resonators

82A and 82B are formed by the

planar conductors

122A and 122B facing the ground conductor 123 with the dielectric substrate 121 interposed therebetween. The

resonators

82A and 82B share the dielectric substrate 121 and the ground conductor 123. The

plane conductors

122A and 122B are not connected to the inner conductor of the coaxial cable and are open.

A main surface of the dielectric substrate 111 on which the flat conductor 112 is formed and a main surface of the dielectric substrate 121 on which the

flat conductors

122A and 122B are formed are opposed to each other at a predetermined distance. In other words, the ground conductor 113 and the ground conductor 123 face each other at a predetermined interval. In the direction from the ground conductor 113 toward the ground conductor 123, the plane conductor 112 is disposed between the ground conductor 113 and the ground conductor 123, and the

plane conductors

122A and 112B are disposed between the plane conductor 112 and the ground conductor 123 There is.

The positions of the

planar conductors

122A and 122B of the plurality of

resonators

82A and 82B are offset from the position of the planar conductor 112 of the resonator 81 in plan view in the direction of the normal to the main surface of the planar conductor 112. The planar conductor 112 is disposed between the planar conductor 122A and the planar conductor 122B in plan view in the direction of the normal to the main surface of the planar conductor 112, and does not overlap with the

planar conductors

122A and 122B.

A space 83A for disposing an object to be heated is formed between the plane conductor 112 and the plane conductor 122A. A space 83B for disposing an object to be heated is formed between the plane conductor 112 and the plane conductor 122B. When high frequency power is supplied to the heating device 80, the

planar conductors

112, 122A, 122B of the

resonators

81, 82A, 82B are electromagnetically coupled to each other.

FIG. 26 is a perspective view of the heating device 80 in which the

samples

22A and 22B are disposed. When heated, the sample 22A in the test tube 21A is disposed in the space 83A between the plane conductor 112 and the plane conductor 122A. The sample 22B in the test tube 21B is disposed in the space 83B between the plane conductor 112 and the plane conductor 122B when heated.

FIG. 28 is a diagram showing simulation results of power characteristics of the heating device 80. As shown in FIG. Here, real part εr ′ of complex relative dielectric constant of pure water and dielectric loss tangent tanδ shown in FIG. 9 were used. The dimension Dcy in the y-axis direction of the

planar conductors

112, 122A, 122B was set to 40 mm. The other conditions were set in the same manner as the above basic conditions. In FIG. 28, “absorbed power of sample” is the power absorbed by the

samples

22A and 22B. “Reflected power” is the power reflected at the input end 115. “Leakage power” is power that leaks from the heating device 80. The “absorbed power of the substrate etc.” is the power absorbed by the

dielectric substrates

111 and 121 and the

test tubes

21A and 21B. In FIG. 28, the absorbed power of the sample, the reflected power, the leaked power, and the absorbed power of the substrate and the like are represented as a percentage of the input power input to the input terminal 115.

When the temperature of the

samples

22A and 22B is 50 ° C., the absorbed power of the

samples

22A and 22B is increased, and about 86% of the input power is absorbed by the

samples

22A and 22B. Therefore, as also shown in the experimental result of FIG. 29, when the temperature of the

samples

22A and 22B is 50 ° C., the heating rate is increased. When the temperature of the

samples

22A and 22B is 50 ° C., the reflected power is suppressed to about 8% of the input power. Further, regardless of the temperature of the

samples

22A and 22B, the ratio of the leaked power is suppressed to 4% or less of the input power.

FIG. 29 is a view showing an example of the experimental results of the time change of the temperature and the reflected power of the

samples

22A and 22B when the

samples

22A and 22B are heated by the heating device 80. Here, the dimension Dcy in the y-axis direction of the

planar conductors

112, 122A, 122B was set to 40 mm. The input power input to the heating device 80 was set to 10 W. The other conditions were set in the same manner as the above basic conditions.

The temperature change of the sample 22A substantially matches the temperature change of the sample 22B, and the

samples

22A and 22B are heated substantially uniformly to each other. In addition, it was also shown by experiments that the heating rate increases when the temperature of the

samples

22A and 22B is around 50 ° C. It was also shown by experiments that when the temperature of the

samples

22A and 22B is around 50 ° C., the reflected power is suppressed to about 8% of the input power.

In the fourth embodiment, the absorption efficiency of high frequency power by the object to be heated is improved as compared to the third embodiment. In addition, as compared with the third embodiment, it is possible to simultaneously and uniformly heat a plurality of the same objects to be heated with higher accuracy. Moreover, compared with the third embodiment, even if the number of resonators is reduced and the resonators are not paired, it is possible to heat a plurality of objects to be heated.

In the above embodiment, a half-wave resonator having a microstrip structure is illustrated, but the structure of the resonator is not limited to this. For example, the dielectric substrate constituting the above-described resonator is not essential. In other words, the structure of the above-mentioned resonator may be changed by replacing the dielectric substrate with air.

Further, in the above embodiment, a resonator having a flat conductor is illustrated, but the resonator may have a curved conductor, a bent flat conductor, or the like instead of the above flat conductor. In addition, the resonator may have a conductor in which a planar portion and the other portion are integrally formed instead of the above-described flat conductor. In this case, the planar portion of the conductor corresponds to the "planar conductor" of the present invention. Further, although the flat ground conductor and the dielectric substrate are illustrated in the above embodiment, the ground conductor and the dielectric substrate may be curved or may be curved.

In the first to third embodiments, planar conductors sandwiching a space for disposing an object to be heated face each other in front of each other, but the planar conductors may be shifted from each other. In particular, in the third embodiment, the configuration in which the flat conductors are mutually offset has the same configuration as that of the fourth embodiment in part, so that the same effect as the fourth embodiment can be obtained.

Finally, the description of the above embodiments is illustrative in all respects and not restrictive. Modifications and variations are possible as appropriate to those skilled in the art. It goes without saying that partial replacement or combination of the configurations shown in different embodiments is possible. The scope of the present invention is indicated not by the embodiments described above but by the claims. Further, the scope of the present invention is intended to include all modifications within the scope and meaning equivalent to the claims.

10, 50, 60, 70, 80 ...

heating devices

11, 12, 61A, 61B, 61C, 62A, 62B, 62C, 81, 82A, 82B ...

resonators

13, 13A, 13B, 83A, 83B ...

spaces

14, 15 ...

coaxial cable

21, 21A, 21B ...

test tube

22, 22A, 22B ...

sample

30, 40 ...

equivalent circuit

31, 32, 41, 42 ...

resonant circuit

111, 121 ...

dielectric substrate

112, 122, 112A, 112B, 112C , 122A, 122B, 122C ...

planar conductor

113, 123 ...

ground conductor

114, 124 ... opening 115 ... input end 125 ...

output end

141, 151 ...

inner conductor

142, 152 ... outer conductor

Claims

A first resonator having a first planar conductor;
A second resonator having a second planar conductor,
The first planar conductor and the second planar conductor are spaced apart and electromagnetically coupled to each other,
A heating device, wherein a space for disposing an object to be heated is formed between the first planar conductor and the second planar conductor.
The first resonator has a first ground conductor facing the first planar conductor,
The second resonator has a second ground conductor facing the second planar conductor,
The heating device according to claim 1, wherein the first ground conductor and the second ground conductor face each other.
In the direction from the first ground conductor to the second ground conductor, the first planar conductor is disposed between the first ground conductor and the second ground conductor, and the second planar conductor is the second planar conductor. The heating device according to claim 2, disposed between the one-sided conductor and the second ground conductor.
The heating device according to any one of claims 1 to 3, wherein the first planar conductor and the second planar conductor face each other.
A plurality of the second resonators are provided,
The position of the second planar conductor of the plurality of second resonators is offset from the position of the first planar conductor in plan view in the direction of the normal to the main surface of the first planar conductor. A heating device according to any one of Items 1 to 3.
A plurality of the first resonators and the second resonators are provided,
The first planar conductors of the plurality of first resonators are electromagnetically coupled to each other,
The heating device according to any one of claims 1 to 5, wherein the second planar conductors of the plurality of second resonators are electromagnetically coupled to each other.
The heating device according to any one of claims 1 to 6, wherein the first planar conductor is connected to a feeder and the second planar conductor is open.
The heating device according to any one of claims 1 to 7, wherein the first resonator and the second resonator are half-wave resonators.