JPWO2013035882A1 - Antenna structure, high-frequency radiation plug, internal combustion engine, and method of manufacturing antenna structure - Google Patents

Abstract

An object of the present invention is to improve high-frequency radiation efficiency in an antenna structure in which a radiation antenna is integrated with a high-frequency transmission line having a laminated structure. The present invention is configured by laminating and integrating a plurality of sheet-like insulators, and a columnar high-frequency transmission line in which a conductor for high-frequency transmission is embedded, and a high frequency is emitted from the high-frequency transmission line. The covering insulator laminated so as to cover the emitting end face, and the emitting end face and the covering insulator so that the high frequency input from the emitting end face is radiated into the space where the covering insulator is exposed. It is an antenna structure characterized by including a radiation antenna embedded between or inside the covering insulator.

Description

  The present invention relates to an antenna structure in which a radiation antenna for radiating a high frequency is covered with a dielectric, a high-frequency radiation plug including the antenna structure, an internal combustion engine including the high-frequency radiation plug, and an antenna structure It is related with the manufacturing method.

  Conventionally, an antenna structure in which a radiating antenna for radiating a high frequency is covered with a dielectric is known. For example, Patent Document 1 discloses an internal combustion engine provided with this type of antenna structure.

  In the internal combustion engine described in Patent Document 1, an electromagnetic wave supply path is embedded in the cylinder head, and an end surface on the combustion chamber side of the electromagnetic wave supply path is a radiation antenna. The radiating antenna is covered with a dielectric.

  Conventionally, a high-frequency transmission line having a laminated structure constituted by laminating and integrating a plurality of sheet-like insulators has been known. For example, Patent Document 2 discloses this type of high-frequency transmission line.

JP 2010-96128 A JP-A-10-190318

  By the way, in an antenna structure in which a radiation antenna is integrated with a high-frequency transmission line of this type of laminated structure, a sheet-like insulator provided with a conductor for a radiation antenna in addition to a conductor for high-frequency transmission is laminated. It is conceivable to integrate the high-frequency transmission line and the radiation antenna. If the conventional high-frequency transmission line lamination technique is used, a conductive pattern is provided as a conductor for the radiation antenna on the sheet-like insulator before lamination.

  In this case, when the antenna structure is seen through from the radiation antenna side, the side surface (thickness surface) of the conductor pattern between the sheet-like insulators becomes the main radiation surface of the radiation antenna. For this reason, the area of the radiation antenna when the antenna structure is seen through from the radiation antenna side (hereinafter referred to as “transparent antenna area”) is not so large, and it is difficult to increase the amount of high-frequency radiation energy.

  The present invention has been made in view of such points, and an object thereof is to increase the amount of high-frequency radiation energy in an antenna structure in which a radiation antenna is integrated with a high-frequency transmission line having a laminated structure. .

  A first invention is configured by laminating and integrating a plurality of sheet-like insulators, a columnar high-frequency transmission line having a high-frequency transmission conductor embedded therein, and high-frequency radiation in the high-frequency transmission line The insulating insulator laminated so as to cover the emitting end face, and the emitting end face and the covering insulator so that a high frequency input from the emitting end face is radiated into a space where the covering insulator is exposed. Or a radiation antenna embedded in the covering insulator.

  In the first invention, the radiation antenna is embedded between the output end face of the high-frequency transmission line having a laminated structure in which a plurality of sheet-like insulators are laminated and the covering insulator, or inside the covering insulator. The radiating antenna is covered with a covering insulator. In the first invention, it is possible to provide a radiation antenna at a location different from between the sheet-like insulators constituting the high-frequency transmission line by laminating the covering insulator in a direction different from the lamination direction of the high-frequency transmission line. Therefore, a radiation antenna is provided between the output end face of the high-frequency transmission line and the covering insulator, or inside the covering insulator.

  According to a second invention, in the first invention, in the high-frequency transmission line, the high-frequency transmission conductor is exposed from the emission end face, and the input side of the radiation antenna is the high-frequency transmission conductor on the emission end face. Abut.

  According to a third invention, in the first or second invention, the covering insulator is formed in a sheet shape.

  4th invention is comprised by the antenna structure of any one of 1st thru | or 3rd invention, and a cylindrical conductor, The said radiation antenna is provided in one end, and is extended from this radiation antenna to the other end side. A high-frequency radiation plug comprising a casing for housing the high-frequency transmission line.

  A fifth invention includes the high-frequency radiation plug according to the fourth invention, and an internal combustion engine main body in which a combustion chamber is formed and the high-frequency radiation plug is attached to the combustion chamber so as to radiate a high frequency. It is an internal combustion engine.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing an antenna structure in which a high-frequency transmission line having a high-frequency transmission conductor embedded therein and a radiation antenna for radiating a high frequency supplied from the high-frequency transmission line are integrated. A first laminating step of laminating a plurality of sheet-like molded bodies prepared from a slurry solution containing ceramic powder and a binder to produce a columnar primary laminated body in which the high-frequency transmission conductor is embedded. And a covering molded body prepared from the slurry solution is laminated on the end surface of the primary laminate, and the radiation antenna is embedded between the end surface and the covering molded body or inside the covering molded body. A second laminating step for producing the secondary laminated body, and a firing step for firing the secondary laminated body.

  According to a seventh aspect of the present invention, there is provided a method of manufacturing an antenna structure in which a high frequency transmission line having a high frequency transmission conductor embedded therein and a radiation antenna for radiating a high frequency supplied from the high frequency transmission line are integrated. Then, a plurality of sheet-like molded bodies prepared from a slurry solution containing a ceramic powder and a binder are stacked and fired to create a columnar high-frequency transmission line in which the high-frequency transmission conductor is embedded. And a covering step of covering the end face of the high-frequency transmission line created in the creating step with a ceramic fired body so that the radiation antenna is embedded.

  In the present invention, it is possible to provide a radiation antenna at a location different from between the sheet-like insulators constituting the high-frequency transmission line by laminating the covering insulator in a direction different from the laminating direction of the high-frequency transmission line. Therefore, the radiation antenna is provided between the output end face of the high-frequency transmission line and the covering insulator, or inside the covering insulator. When the radiation antenna is provided in this way, the size of the radiation antenna when the antenna structure is seen through from the radiation antenna side is limited compared to the case where the radiation antenna is provided between the sheet-like insulators constituting the high-frequency transmission line. It is hard to be done. Therefore, since the area of the fluoroscopic antenna can be increased, the amount of high-frequency radiation energy can be increased.

1 is a longitudinal sectional view of an internal combustion engine according to an embodiment. It is a front view of the ceiling surface of the combustion chamber of the internal combustion engine which concerns on embodiment. It is a block diagram of the ignition device and electromagnetic wave radiation device concerning an embodiment. It is a longitudinal cross-sectional view of the plug for high frequency radiation which concerns on embodiment. It is a perspective view by the side of the radiation antenna of the ceramic structure which concerns on embodiment. It is drawing for demonstrating the 1st lamination | stacking step which concerns on embodiment. It is drawing for demonstrating the 2nd lamination | stacking step which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

The present embodiment is an internal combustion engine 10 according to the present invention. The internal combustion engine 10 is a reciprocating type internal combustion engine in which a piston 23 reciprocates. The internal combustion engine 10 includes an internal combustion engine body 11, an ignition device 12, an electromagnetic wave emission device 13, and a control device 35. In the internal combustion engine 10, a combustion cycle in which the air-fuel mixture is ignited by the ignition device 12 and the air-fuel mixture is combusted is repeatedly performed.
-Internal combustion engine body-

  As shown in FIG. 1, the internal combustion engine body 11 includes a cylinder block 21, a cylinder head 22, and a piston 23. A plurality of cylinders 24 having a circular cross section are formed in the cylinder block 21. A piston 23 is provided in each cylinder 24 so as to reciprocate. The piston 23 is connected to the crankshaft via a connecting rod (not shown). The crankshaft is rotatably supported by the cylinder block 21. When the piston 23 reciprocates in the axial direction of the cylinder 24 in each cylinder 24, the connecting rod converts the reciprocating motion of the piston 23 into the rotational motion of the crankshaft.

  The cylinder head 22 is placed on the cylinder block 21 with the gasket 18 interposed therebetween. The cylinder head 22, together with the cylinder 24, the piston 23, and the gasket 18, constitutes a partition member that partitions the combustion chamber 20 having a circular cross section. The diameter of the combustion chamber 20 is, for example, about half the wavelength of the microwave that the electromagnetic wave emission device 13 radiates to the combustion chamber 20.

  The cylinder head 22 is provided with one spark plug 40 that constitutes a part of the ignition device 12 for each cylinder 24. As shown in FIG. 2, in the spark plug 40, the tip exposed to the combustion chamber 20 is positioned at the center of the ceiling surface 51 of the combustion chamber 20 (the surface exposed to the combustion chamber 20 in the cylinder head 22). . The outer periphery of the distal end portion of the spark plug 40 is circular as viewed from the axial direction. A center electrode 40 a and a ground electrode 40 b are provided at the tip of the spark plug 40. A discharge gap is formed between the tip of the center electrode 40a and the tip of the ground electrode 40b.

An intake port 25 and an exhaust port 26 are formed in the cylinder head 22 for each cylinder 24. The intake port 25 is provided with an intake valve 27 that opens and closes an intake side opening 25a of the intake port 25, and an injector 29 that injects fuel. On the other hand, the exhaust port 26 is provided with an exhaust valve 28 for opening and closing the exhaust side opening 26 a of the exhaust port 26.
-Ignition device-

  The ignition device 12 is provided for each combustion chamber 20. As shown in FIG. 3, each ignition device 12 includes an ignition coil 14 that outputs a high voltage pulse, and an ignition plug 40 that is supplied with the high voltage pulse output from the ignition coil 14.

  The ignition coil 14 is connected to a DC power source (not shown). When the ignition coil 14 receives the ignition signal from the control device 35, the ignition coil 14 boosts the voltage applied from the DC power supply, and outputs the boosted high voltage pulse to the center electrode 40 a of the spark plug 40. In the spark plug 40, when a high voltage pulse is applied to the center electrode 40a, dielectric breakdown occurs in the discharge gap and spark discharge occurs. A discharge plasma is generated in the discharge path of the spark discharge. A negative voltage is applied to the center electrode 40a as a high voltage pulse.

The ignition device 12 may include a plasma expansion unit that supplies electric energy to the discharge plasma to expand the discharge plasma. A plasma expansion part expands a spark discharge by supplying high frequency (for example, microwave) energy to discharge plasma, for example. According to the plasma expansion part, it is possible to improve the stability of ignition with respect to a lean air-fuel mixture. The electromagnetic wave emission device 13 may be used as the plasma expansion unit.
-Electromagnetic radiation device-

  As shown in FIG. 3, the electromagnetic wave radiation device 13 includes an electromagnetic wave generator 31, an electromagnetic wave switch 32, and a high frequency radiation plug 34. In the electromagnetic wave radiation device 13, one electromagnetic wave generator 31 and one electromagnetic wave switch 32 are provided, and a high frequency radiation plug 34 is provided for each combustion chamber 20.

  When receiving the electromagnetic wave drive signal (pulse signal) from the control device 35, the electromagnetic wave generator 31 continuously outputs the microwave over the time of the pulse width of the electromagnetic wave drive signal. In the electromagnetic wave generator 31, a semiconductor oscillator generates microwaves. In place of the semiconductor oscillator, another oscillator such as a magnetron may be used.

  The electromagnetic wave switch 32 includes one input terminal and a plurality of output terminals provided for each high frequency radiation plug 34. The input terminal is electrically connected to the electromagnetic wave generator 31. Each output terminal is electrically connected to the input terminal of the corresponding high-frequency radiation plug 34. The electromagnetic wave switch 32 is controlled by the control device 35 and sequentially switches the supply destination of the microwaves output from the electromagnetic wave generator 31 between the plurality of high-frequency radiation plugs 34.

  The high frequency radiation plug 34 is formed in a substantially cylindrical shape. As shown in FIG. 4, the high-frequency radiation plug 34 includes a ceramic structure 36 in which conductors 61 and 62 are embedded in a ceramic 63 (electrical insulator), and a casing 37 that houses the ceramic structure 36. Yes.

  The ceramic structure 36 is formed in a prismatic shape. The cross-sectional shape of the ceramic structure 36 is uniform over the length direction. The cross-sectional shape of the ceramic structure 36 is, for example, a square. The ceramic structure 36 has the same length of one side in any cross section, and the length of one side is, for example, 1.5 to 5 mm (for example, 3 mm). The ceramic structure 36 constitutes an antenna structure including the high-frequency transmission line 60, the radiation antenna 16, and the covering insulator 90.

  As shown in FIG. 5, the high-frequency transmission line 60 is configured by stacking and integrating a plurality of sheet-like insulators 66. A center conductor 61 and an outer conductor 62 are embedded in the ceramic 63 of the high-frequency transmission line 60 as high-frequency transmission conductors. The center conductor 61 is a linear conductor. The center conductor 61 is provided on the axial center of the ceramic structure 36 over the entire length of the high-frequency transmission line 60. On the other hand, the outer conductor 62 is configured by connecting a pair of conductor patterns 62a and 62b with a cylindrical conductor (via hole) at equal intervals (illustration of the cylindrical conductor is omitted in FIG. 5). ) Only one end of the outer conductor 62 is exposed at the end face of the ceramic structure 36. In the high frequency radiation plug 34, a microwave input terminal is provided on one end face (incident end face) of the high frequency transmission line 60 where the outer conductor 62 is exposed. In the high frequency transmission line 60, the microwave input from the input terminal is transmitted to the radiation antenna 16 without leaking outside the outer conductor 62.

  As shown in FIG. 5, the radiation antenna 16 extends inside the ceramic structure 36 along the emission end face 80 of the high-frequency transmission line 60, and the microwave input from the emission end face 80 is radiated. The radiation antenna 16 is sandwiched between the output end face 80 of the high-frequency transmission line 60 and the rectangular sheet-shaped covering insulator 90. The radiation antenna 16 is formed in a rod shape and is bent along the emission end face 80 of the high-frequency transmission line 60. Specifically, the radiation antenna 16 is formed in a spiral shape that turns in a rectangular shape around the axis of the center conductor 61. The radiating antenna 16 is covered with a covering insulator 90 that is laminated and fixed on the output end face 80 of the high-frequency transmission line 60. The radiation antenna 16 is embedded in the ceramic structure 36 by integrating the high-frequency transmission line 60 and the covering insulator 90. The entire surface of the radiating antenna 16 is covered with a ceramic 63. The central portion 16 a of the radiating antenna 16 is in contact with one end of the central conductor 61.

  In the ceramic structure 36, as shown in FIG. 4, one end surface 65 and a part of the side surface become an exposed surface exposed to the combustion chamber 20. Of these exposed surfaces, the end surface 65 of the ceramic structure 36 from which most of the microwave radiated from the radiation antenna 16 is radiated to the combustion chamber 20 constitutes the main radiation surface 65. The main radiation surface 65 is a surface where the area of the radiation antenna 16 when viewed from the front is the largest among the exposed surfaces.

  The casing 37 is formed in a cylindrical shape having a circular outer peripheral shape and a rectangular inner peripheral shape in cross-sectional view. In sectional view, the inner peripheral shape of the casing 37 and the side length of the inner periphery are the same as the outer peripheral shape of the ceramic structure 36 and the side length of the outer periphery. A ceramic structure 36 is fitted into the casing 37 such that the main radiation surface 65 is exposed at one end and the incident end surface of the high-frequency transmission line 60 is exposed at the other end. From one end of the casing 37, the main radiation surface 65 side of the ceramic structure 36 protrudes.

  The outer diameter of the casing 37 changes at one place in the axial direction of the casing 37. A step is formed on the outer peripheral surface of the casing 37 only at one location. In the casing 37, the outer diameter on the distal end side at which the main radiation surface 65 is exposed is smaller than the outer diameter on the proximal end side where the input end surface is present.

  The high frequency radiation plug 34 is attached to the cylinder head 22 so that the main radiation surface 65 is exposed to the combustion chamber 20. The high frequency radiation plug 34 is screwed into the mounting hole of the cylinder head 22. The high frequency radiation plug 34 has an input terminal of the high frequency transmission line 60 connected to an output terminal of the electromagnetic wave switch 32 via a coaxial cable (not shown). In the high frequency radiation plug 34, when a microwave is input from the input terminal of the high frequency transmission line 60, the microwave passes inside the outer conductor 62 of the high frequency transmission line 60. The microwaves that have passed through the high-frequency transmission line 60 are radiated from the radiation antenna 16 through the main radiation surface 65 to the combustion chamber 20.

Further, in the internal combustion engine body 11, a plurality of receiving antennas 52 that resonate with microwaves radiated from the radiation antenna 16 to the combustion chamber 20 are provided on the partition member that partitions the combustion chamber 20. Each receiving antenna 52 is formed in an annular shape. As shown in FIG. 1, two receiving antennas 52 are provided on the top of the piston 23. Each receiving antenna 52 is electrically insulated from the piston 23 by an insulating layer 56 formed on the top surface of the piston 23, and is provided in an electrically floating state.
-Manufacturing method of ceramic structure-

  A method for manufacturing the ceramic structure 36 will be described with reference to FIGS.

  First, in the first step, a ceramic powder and a binder are mixed to create a slurry. And this slurry is shape | molded by the doctor blade method etc., and the sheet-like molded objects 66 and 90 (green sheet) are created. A plurality of green sheets 66 and 90 are provided for the high-frequency transmission line 60 and one for the radiation antenna 16.

  Next, in a second step, the transmission green sheet 66 for the high-frequency transmission line 60 is provided with conductor layers 61, 62a, 62b and a cylindrical conductor (a via hole) as high-frequency transmission conductors. In addition, a spiral conductor layer 16 is provided as a conductor for the radiation antenna 16 on the antenna green sheet 90 for the radiation antenna 16. The conductor layers 16, 61, 62a, and 62b are formed by printing and applying metallized ink.

  Next, in a third step, a prismatic primary laminate 105 in which a plurality of transmission green sheets 66 are laminated and adhered is created. The third step constitutes the first stacking step.

  Next, in the fourth step, the antenna laminate green sheet 90 is laminated and adhered to the portion of the primary laminate 105 that becomes the output end face 80 of the high-frequency transmission line 60 to create the secondary laminate 106. The fourth step constitutes the second stacking step.

  Next, in the fifth step, the secondary laminate 106 is fired at a predetermined temperature, and the transmission green sheet 66 and the antenna green sheet 90 are integrated. Thereby, the ceramic structure 36 is completed. The antenna green sheet 90 becomes the covering insulator 90. The fifth step constitutes a firing step.

In the embodiment, the conductor layer 16 serving as the conductor for the radiating antenna 16 is formed on the antenna green sheet 90. However, the conductor layer 16 serving as the conductor for the radiating antenna 16 is printed on the end surface of the primary laminate 105. The secondary laminate 106 may be formed by stacking and adhering the green sheet 90 for an antenna without a conductor layer thereon.
-Control device operation-

  The operation of the control device 35 will be described. The control device 35 performs a first operation for instructing the ignition device 12 to ignite the air-fuel mixture in one combustion cycle for each combustion chamber 20, and a microwave is applied to the electromagnetic wave emission device 13 after the ignition of the air-fuel mixture. A second operation for instructing radiation is performed.

  Specifically, the control device 35 performs the first operation at the ignition timing at which the piston 23 is positioned before the compression top dead center. The control device 35 outputs an ignition signal as the first operation.

  When the ignition device 12 receives the ignition signal, spark discharge occurs in the discharge gap of the spark plug 40 as described above. The air-fuel mixture is ignited by spark discharge. When the air-fuel mixture is ignited, the flame spreads from the ignition position at the center of the combustion chamber 20 toward the wall surface of the cylinder 24.

  After the air-fuel mixture has ignited, the control device 35 performs the second operation, for example, at the start timing of the second half period of flame propagation. The control device 35 outputs an electromagnetic wave drive signal as the second operation.

  When receiving the electromagnetic wave drive signal, the electromagnetic wave radiation device 13 radiates a microwave continuous wave (CW) from the radiation antenna 16 as described above. Microwaves are emitted over the second half of the flame propagation. Note that the output timing and pulse width of the electromagnetic wave drive signal may be set so that the microwave is emitted over a period in which the flame passes through the region where the two receiving antennas 52 are provided.

  In each receiving antenna 52, the microwave resonates. In the vicinity of the two receiving antennas 52, a strong electric field region having a relatively strong electric field strength is formed in the combustion chamber 20 throughout the second half period of the flame propagation. The propagation speed of the flame is increased by receiving microwave energy when the flame passes through the strong electric field region.

When the microwave energy is large, microwave plasma is generated in the strong electric field region. Active species (for example, OH radicals) are generated in the microwave plasma generation region. The propagation speed of the flame passing through the strong electric field region is increased by the active species.
-Effect of the embodiment-

In this embodiment, the radiating antenna 16 is placed at a place different from between the sheet-like insulators 66 constituting the high-frequency transmission line 60 by laminating the covering insulator 90 in a direction different from the laminating direction of the high-frequency transmission line 60. Therefore, the radiation antenna 16 is provided between the output end face 80 of the high-frequency transmission line 60 and the covering insulator 90 or inside the covering insulator 90. When the radiating antenna 16 is provided in this way, the radiating antenna 16 when the antenna structure is seen through from the radiating antenna 16 side is compared with the case where the radiating antenna is provided between the sheet-like insulators constituting the high-frequency transmission line. Dimensions are not easily restricted. Accordingly, since the area of the fluoroscopic antenna can be increased, the amount of microwave radiation energy can be increased. Then, the amount of reflected wave energy when the microwave energy is larger than the size of the radiation antenna 16 is reduced.
-Modification of the embodiment-

  In the modification, the manufacturing method of the ceramic structure 36 is different from the embodiment. Since the first step and the second step are the same, description thereof is omitted.

  In the third step, a plurality of transmission green sheets 66 are laminated and fired to form a prismatic shape in which conductor layers 61, 62a, 62b and a cylindrical conductor (via hole) are embedded as high frequency transmission conductors. The high-frequency transmission line 60 is created. The third step constitutes a creation step. Next, in a fourth step, the antenna green sheet 90 is fired to form a plate-like ceramic fired body.

Next, in the fifth step, the end face of the high-frequency transmission line 60 created in the creating step is covered with the ceramic fired body in the fourth step so that the radiation antenna 16 is embedded, and fixed with an adhesive. The fifth step constitutes a coating step.
<< Other Embodiments >>

  The embodiment may be configured as follows.

  In the above-described embodiment, the transmission green sheet 66 and the transmission antenna for the high frequency transmission and the conductor for the radiation antenna 16 are provided in different areas in one green sheet, and the green sheet is bent at the boundary between these areas. The covering green sheet 67 may be configured.

  Moreover, in the said embodiment, although the radiation antenna 16 was formed in the spiral shape which turns in a rectangle, the radiation antenna 16 may be formed in the spiral shape which turns in a circle. Further, the radiation antenna 16 may be a rod-shaped antenna that is bent so as to reciprocate a plurality of times when the main radiation surface 65 is seen through from the front.

  In the embodiment, the center conductor 61 is in contact with the radiating antenna 16, but the center conductor 61 may be capacitively coupled to the radiating antenna 16.

  In the embodiment, a plurality of high-frequency radiation plugs 34 may be provided in the internal combustion engine body 11.

  In the embodiment, the outer conductor 62 of the high-frequency transmission line 60 may be omitted. In that case, in the high-frequency transmission line 60, microwaves are transmitted between the outer peripheral surface of the center conductor 61 and the inner peripheral surface of the casing 37.

  Moreover, in the said embodiment, the center conductor 61 of the high frequency transmission line 60 is abbreviate | omitted, and it is good also considering the high frequency transmission line 60 as a waveguide.

  In the above embodiment, the covering insulator 90 may be constituted by a plurality of sheet-like insulators. In that case, the radiation antenna 16 may be embedded between the sheet-like insulators. In this case, a conductor for electrically connecting the radiation antenna 16 and the central conductor 61 may be embedded in a sheet-like insulator on the high-frequency transmission line 60 side of the radiation insulator 16 in the covering insulator 90. .

  In the embodiment, the internal combustion engine 10 may be of another type (diesel engine, ethanol engine, gas turbine, etc.). Further, when the internal combustion engine 10 is an aircraft engine, when the engine misfires, the ignition device 12 and the electromagnetic wave radiation device 13 are used to generate a microwave plasma obtained by expanding the spark discharge plasma using a microwave, and reignition is performed. You may go.

  As described above, the present invention relates to an antenna structure in which a radiating antenna for radiating a high frequency is covered with a dielectric, a high-frequency radiating plug including the antenna structure, and an internal combustion engine including the high-frequency radiating plug. It is useful for an engine and a method for manufacturing an antenna structure.

16 Radiating antenna
36 Ceramic structure (antenna structure)
60 High-frequency transmission line
66 Sheet insulator
61 Center conductor (conductor for high-frequency transmission)
62 Outer conductor (conductor for high-frequency transmission)
80 Output end face
90 Coated insulation

Claims (7)

A columnar high-frequency transmission line configured by laminating and integrating a plurality of sheet-like insulators, with a high-frequency transmission conductor embedded therein,
A coating insulator laminated so as to cover an emission end face from which a high frequency is emitted in the high-frequency transmission line;
A radiating antenna embedded between the emitting end face and the covering insulator or inside the covering insulator so that a high frequency input from the emitting end face is radiated into the space where the covering insulator is exposed. And an antenna structure. In claim 1,
In the high-frequency transmission line, the high-frequency transmission conductor is exposed from the emission end face,
The antenna structure according to claim 1, wherein an input side of the radiation antenna is in contact with the high-frequency transmission conductor on the emission end face. In claim 1 or 2,
An antenna structure according to claim 1, wherein the covering insulator is formed in a sheet shape. The antenna structure according to any one of claims 1 to 3,
A high-frequency radiation plug comprising a cylindrical conductor, the radiation antenna being provided at one end, and a casing accommodating the high-frequency transmission line extending from the radiation antenna to the other end side. A high-frequency radiation plug according to claim 4,
An internal combustion engine comprising a combustion chamber and an internal combustion engine body to which the high frequency radiation plug is attached so as to radiate a high frequency to the combustion chamber. A method of manufacturing an antenna structure in which a high-frequency transmission line in which a conductor for high-frequency transmission is embedded and a radiation antenna for radiating a high frequency supplied from the high-frequency transmission line are integrated,
A first lamination step of laminating a plurality of sheet-like molded bodies prepared from a slurry solution containing ceramic powder and a binder to create a columnar primary laminate in which the high-frequency transmission conductor is embedded;
The covering molded body prepared from the slurry solution was laminated on the end surface of the primary laminate, and the radiation antenna was embedded between the end surface and the covering molded body or inside the covering molded body. A second lamination step for creating a secondary laminate;
A method for manufacturing an antenna structure, comprising: a firing step for firing the secondary laminate. A method of manufacturing an antenna structure in which a high-frequency transmission line in which a conductor for high-frequency transmission is embedded and a radiation antenna for radiating a high frequency supplied from the high-frequency transmission line are integrated,
A step of creating a columnar high-frequency transmission line in which the conductor for high-frequency transmission is embedded by laminating and firing a plurality of sheet-like molded bodies prepared from a slurry solution containing ceramic powder and a binder,
An antenna structure manufacturing method comprising: a covering step of covering an end face of the high-frequency transmission line created in the creating step with a ceramic fired body so that the radiation antenna is embedded.