Antenna device, array antenna device, and microwave heating device

Abstract

An antenna device according to the present disclosure comprises: an antenna excitation element; a first conductor part that is connected to the antenna excitation element at a first position to supply power; a second conductor part that is connected to the antenna excitation element to supply power at a second position that is different from the first position, the second position being such that an angle formed by a line from the first position to a center of the antenna excitation element and a line from the second position to the center of the antenna excitation element is 90 degrees, and a distance from the center of the antenna excitation element to the second position is equal to the distance from the center of the antenna excitation element to the first position; a strip line part having a first transmission path that is connected to the first conductor part to supply power, and a second transmission path that is connected to the second conductor part to supply power and that has a length different from that of the first transmission path by 1 / 4 wavelength of the frequency used; and a rotation part that rotates the antenna excitation element.

Description

Antenna device, array antenna device, and microwave heating device

[0001] The present disclosure relates to an antenna device, an array antenna device, and a microwave heating device.

[0002] In recent years, in response to the increasing sophistication and performance of wireless communications and radar, phased array antennas capable of scanning radiation patterns or controlling directivity have become widely used as antenna devices for wireless communications or radar. A phased array antenna is an array antenna device in which multiple element antennas are arranged, each connected to a phase shifter. Digital phase shifters, which change the radiation phase of an element antenna by switching a transmission line using semiconductor switches, such as diodes and transistors, are widely used as phase shifters in phased array antennas. Digital phase shifters have the advantages of being compact when integrated into a chip and of easily controlling the phase because the transmission phase can be electronically controlled. On the other hand, digital phase shifters have the disadvantage of requiring multiple semiconductor switches on the transmission line, resulting in high transmission loss. Furthermore, semiconductor switches generally require expensive semiconductor processes for manufacturing, making it difficult to reduce the cost of communication equipment and radar.

[0003] The following Patent Document 1 discloses an array antenna device that controls the radiation phase of multiple element antennas without using a digital phase shifter. The array antenna device disclosed in Patent Document 1 has multiple probe insertion holes formed on the upper wall surface of the wide surface of a waveguide and multiple connection shaft insertion holes formed on the opposing lower wall surface. A circularly polarized antenna, typically a helical antenna, and a feed pin are inserted into the upper wall surface, while a connection shaft equipped with a feed probe and a rotating shaft is inserted into the lower wall surface. The rotating shaft is connected to a rotation device, such as a motor, and a control device located outside the lower wall surface. This allows the multiple circularly polarized element antennas to be rotated individually, thereby adjusting the antenna radiation phase for each element. As a result, the radiation phase can be adjusted using only relatively inexpensive mechanical rotation control, such as a motor, rather than electronic control, such as a semiconductor switch. Furthermore, the configuration simply involves loading feed pins onto a low-loss waveguide feed system, thereby achieving low cost and low loss and enabling efficient beamforming.

[0004] Patent No. 6584727

[0005] The array antenna device of Patent Document 1 is configured as described above, and aims to reduce the cost and loss of the array antenna device, while also enabling beam scanning in a desired direction by simply rotating the antenna elements. However, because the configuration basically uses a three-dimensional antenna such as a helical antenna, the antenna height must be set to about a quarter wavelength at the operating frequency, which poses a problem of making the antenna device large.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a small antenna device and a microwave heating device using the same, while taking advantage of the advantage of the above-mentioned antenna device, which is that beam scanning is possible by rotating the antenna.

[0007] According to a first aspect of the present invention, an antenna device includes: an antenna excitation element; a first conductor portion connected to the antenna excitation element at a first position to feed power; a second conductor portion connected to the antenna excitation element at a second position where the angle between the first position and the center of the antenna excitation element and the angle between a second position different from the first position and the center of the antenna excitation element are 90 degrees and the distance from the center of the antenna excitation element is equal to the distance from the center of the antenna excitation element to the first position; a strip line portion having a first transmission line connected to the first conductor portion to feed power; and a second transmission line connected to the second conductor portion to feed power, the second transmission line having a length different from that of the first transmission line by ¼ wavelength of the operating frequency; and a rotating portion that rotates the antenna excitation element.

[0008] According to this invention, it is possible to reduce the height of the antenna element.

[0009] 1A is a structural diagram of an antenna element used in an antenna device according to a first embodiment of the present invention. FIG. 1A shows a perspective view of the antenna element. FIG. 1B shows an overall side view. FIG. 1C shows a structural diagram of an antenna element used in an antenna device according to a first embodiment of the present invention. FIG. 1C shows a top view of an antenna excitation element. FIG. 1D shows a top view of a hollow strip line section. FIG. 1D shows a structural diagram of an array antenna device using the antenna device according to the first embodiment of the present invention. FIG. 1C shows a structural diagram of an antenna device according to a second embodiment of the present invention. FIG. 3A shows an overall top view. FIG. 3B shows an overall side view. FIG. 3C shows a top view of an antenna excitation element. FIG. 3D shows a top view of a strip line section. FIG. 4A shows a structural diagram of an antenna device according to a third embodiment of the present invention. FIG. 4B shows a side view of an antenna excitation element. FIG. 4C is a structural diagram of an antenna device according to embodiment 3 of the present invention. FIG. 4D is a top view of a strip line portion. FIG. 4E is a structural diagram of an antenna device according to embodiment 3 of the present invention. FIG. 4F is a top view of a ground conductor. FIG. 4G is a structural diagram of a microwave heating device according to embodiment 4 of the present invention. FIG. 4H is a structural diagram of a microwave heating device according to embodiment 5 of the present invention. FIG. 4I is a structural diagram of a microwave heating device according to embodiment 6 of the present invention.

[0010] In order to explain the present invention in more detail, embodiments of the present invention will be described below with reference to the accompanying drawings.

[0011] <Embodiment 1> The drawings included in FIG. 1 are structural diagrams of antenna elements used in an antenna device. FIG. 1 includes FIGS. 1A, 1B, 1C, and 1D. FIG. 1A is an overall perspective view, FIG. 1B is an overall side view, FIG. 1C is a top view of an antenna excitation element, and FIG. 1D is a top view of a hollow strip line section. FIG. 2 is a cross-sectional view of an array antenna device using the antenna device of FIG. 1. In FIGS. 1 and 2, a waveguide 1 is a rectangular waveguide having two wide wall surfaces and two narrow wall surfaces each having an area smaller than that of the wide wall surfaces. The two wide wall surfaces are opposed to each other, with one of the two wide wall surfaces being a first wall surface 1a and the other being a second wall surface 1b. The two narrow wall surfaces are also opposed to each other in the same manner as the two wide wall surfaces. 1 shows an example in which the waveguide 1 has two wide wall surfaces and two narrow wall surfaces, but the two wide wall surfaces and the two narrow wall surfaces may have the same area. In the first embodiment, the waveguide 1 is provided with an input end 1c for a high-frequency signal and a short-circuit end 1d (or a short-circuit wall at the end of the waveguide 1) at the end of the waveguide 1 facing the input end 1c.

[0012] The probe insertion hole 5 for inserting a feed probe 4 (which is not limited to a conductor portion or an example of a conductor) for connecting to the antenna excitation element 2 and the hollow strip line 3 has a diameter larger than that of the feed probe 4 so that the feed probe 4 can be inserted, and is sufficiently smaller than the wavelength of the high-frequency signal transmitted through the waveguide 1. The probe insertion hole is formed on the first wall surface 1a of the waveguide 1 at a position directly below the center of the antenna element 2.

[0013] A connection shaft insertion hole 7 for inserting a connection shaft 6 for connection to the power feed probe 4 is formed on the second wall surface 1b of the waveguide 1 so as to be opposite to the probe insertion hole 5. Like the probe insertion hole 5, the connection shaft insertion hole 7 has a larger diameter than the connection shaft 6 and is sufficiently smaller than the wavelength of the high-frequency signal transmitted within the waveguide 1.

[0014] As shown in FIGS. 1A, 1B, and 1C, in this first embodiment, the antenna excitation element 2 is a circular patch, floating in midair. While the diagram included in FIG. 1 illustrates the antenna excitation element 2 as a circle, the shape is not limited to a circle and may be other shapes. For example, the antenna excitation element 2 may be a square or polygon. A first feed pin 8a and a second feed pin 8b are connected at a distance X from the center of the antenna excitation element 2. The first feed pin 8a and the second feed pin 8b are positioned so that the angle between each feed pin and the center of the antenna excitation element 2 is 90°. The distance X is determined by the impedance of the antenna excitation element and varies depending on the shape of the antenna excitation element 2 and the distance between the antenna excitation element 2 and the first wall surface 1a of the waveguide 1. In this first embodiment, to obtain a desired antenna gain, the distance between the antenna excitation element 2 and the first wall surface 1a of the waveguide 1 is set to approximately 1 / 10 of the wavelength at the operating frequency. This distance may be changed arbitrarily depending on system requirements. The 90° angle exemplified throughout the present embodiment need not necessarily be strictly 90°, but may also be a concept that includes a range within which design errors and performance are tolerated (for example, within ±5°, but not limited thereto; this value may be changed as appropriate depending on the performance of the antenna excitation element). The first feed pin 8a and the second feed pin 8b are disposed at equal distances X from the center of the antenna excitation element 2. Here, the term "equal distances" from the center of the antenna excitation element 2 does not necessarily have to be exactly equal distances, but may be a concept that includes a range within which design errors and performance are tolerated (for example, within ±3% of the distance X, but not limited thereto; this value may be changed depending on the distance X and the size of the antenna excitation element 2).

[0015] 1B and 1D, in this first embodiment, in order to feed power to the antenna excitation element 2, a hollow strip line 3 is disposed between the antenna excitation element 2 and the first wall surface 1a of the waveguide 1. The detailed location of the hollow strip line 3 is set to be sufficiently smaller than the distance between the antenna excitation element 2 and the first wall surface 1a of the waveguide 1, for example, approximately 1 / 10 of the wavelength of the frequency used, and the distance is set so that the first wall surface 1a of the waveguide 1 becomes the GND of the hollow strip line 3.

[0016] The hollow strip line 3 comprises a first connection pad 9a for connecting the feed probe 4 and the hollow strip line 3, a first line 11a (not limiting, but an example of a transmission line) connecting the first connection pad 9a and the power distribution circuit 10, a second line 11b (not limiting, but an example of a second transmission line) electrically connected to the output end of the power distribution circuit 10 via the first feed pin 8a (not limiting, but an example of a second conductor portion or a second conductor) and the second connection pad, and a third line 11c (not limiting, but an example of a first transmission line) connected to the other output end of the power distribution circuit 10 via the second feed pin 8b (not limiting, but an example of a first conductor portion or a first conductor) and a third connection pad.

[0017] The length relationship between the second line 11b and the third line 11c is such that, when the length of the second line 11b is Y, the length of the third line 11c is (the physical length of Y + λ / 4). Here, λ represents the wavelength at the operating frequency. This is to realize a line with a 90° phase difference in order to realize a circularly polarized antenna. Although the first embodiment describes a case in which the length of the first line 11a is longer than the radius of the antenna excitation element 2, it may be shorter than the radius of the antenna excitation element 2 as long as the requirements are met. The notch in the power distribution circuit 10 and the presence or absence and shape of a matching circuit in each line may be changed according to the required specifications. While the diagram included in FIG. 1 illustrates the second line 11b and the third line 11c as arc-shaped along the antenna excitation element, this is not limiting. The second line 11b and the third line 11c may or may not have an arc shape at least partially aligned with the antenna excitation element. For example, the second line 11b and the third line 11c may have a rectangular shape or the like. Note that the physical length of λ / 4 does not necessarily mean a quarter of the wavelength at the operating frequency, but may also refer to a range within which design errors and performance are tolerated (for example, and without limitation, within plus or minus 5% of the physical length of λ / 4. Note that this value may be changed as appropriate depending on the wavelength, the performance of the antenna excitation element, etc.).

[0018] The feed probe 4 and the first connection pad 9a, the first feed pin 8a and the second connection pad 9b, and the second feed pin 8b and the third connection pad 9c are electrically connected to each other using, for example, a conductive material, a screw, etc. This electrically connects the waveguide 1 to the antenna excitation element 2, enabling operation as a circularly polarized antenna.

[0019] The connection shaft 6 is made of an insulator such as a dielectric material. The connection shaft 6 is inserted through a connection shaft insertion hole 7 formed in the second wall surface 1 b of the waveguide 1, and one end of the connection shaft 6 inside the waveguide 1 is connected to one end of the power feed probe 5 that is different from the end connected to the hollow strip line 3.

[0020] One possible method for connecting the power feed probe 4 and the connection shaft 6 is to provide a screw hole in the connection shaft 6 and screw the power feed probe 4 in. Another possible method is to form a fitting portion in the connection shaft 6 and insert the power feed probe 4 into the fitting portion of the connection shaft 6 to secure it in place.

[0021] The rotating shaft 12 is made of a metal conductor, and one end is connected to the end of the connection shaft 6 that is not connected to the feed probe 4. As with the connection between the feed probe 4 and the connection shaft 6, the connection between the connection shaft 6 and the rotating shaft 7 can be achieved by screwing or by forming a fitting. Note that the connection position between the connection shaft 6 and the rotating shaft 12 may be outside the waveguide 1 to avoid contact between the metal parts that form the waveguide 1 and the feed probe 4. As shown in FIG. 1B , the rotating shaft 12 is positioned so as to be located on the central axis of the antenna excitation element 2. Therefore, rotation by the rotating shaft 12 enables the antenna excitation element 2 to rotate around the center of the antenna excitation element 2 as an axis.

[0022] The rotation device 13 is realized by, for example, an electric motor such as a DC motor, an AC motor, or a stepping motor, or a motor. The rotation device 13 is connected to a rotating shaft 12, and by rotating the rotating shaft 12, the antenna launch element 2 and the hollow stripline 3 are rotated together. This is because the antenna launch element 2 and the hollow stripline 3 are fixed only by the feed probe 4, the antenna launch element 2 and the hollow stripline 3 are suspended in midair, and the probe insertion hole 5 is larger in diameter than the feed probe 4, so that the feed probe 4 and the waveguide 1 do not come into contact with each other. Here, the rotation device 13 may also be referred to as a rotating unit. The rotating unit (or the rotation device 13) may also include a gear or a gear-like configuration for rotating the antenna launch element 2 about the rotating shaft 12. If the rotating unit is a gear, the gear may be rotated by a motor or the like, and the antenna launch element 2 may rotate about the rotating shaft 12 due to the rotation of the gear, which is the rotating unit. As described above, the rotating section (or the rotating device 13) may have any configuration as long as it contributes to directly or indirectly rotating the antenna excitation element 2. In this example, the configuration is not limited to, but may be such that the hollow stripline 3 rotates when the rotating shaft 12 is rotated, and the rotation of the hollow stripline 3 causes the antenna excitation element 2 connected to the hollow stripline 3 via the feed pin 27 to rotate while maintaining electrical connection with the feed pin 27. For example, the rotating shaft 12 may be directly connected to the center of the antenna excitation element 2 without being connected to the feed probe 4, so that the antenna excitation element 2 can be directly rotated.

[0023] The control device 14 includes a rotation drive device 15 and a rotation control device 16, and controls the rotation of the rotation device 13. This allows the control device 14 to individually control the multiple rotation devices 13 when configured as an array antenna device such as that shown in FIG. 2. The control device 14 may also be referred to as a control unit. The control unit (or the control device 14) does not necessarily have to include both the rotation drive device 15 and the rotation control device 16, and may include either one of them, or a combination of both. In the following embodiments, a configuration in which the control device 14 (control unit) includes both the rotation drive device 15 and the rotation control device 16 will be described, but is not limited to this.

[0024] Rotation drive device 15 is a motor unit realized by, for example, a semiconductor integrated circuit, a network interface for communication equipment or the like, a power supply circuit, a drive current generating circuit, etc. Rotation drive device 15 outputs a drive current corresponding to a command value output from rotation control device 16 to rotation device 13, thereby driving rotation device 13 so that rotation shaft 12 rotates to a predetermined angle.

[0025] Rotation control device 16 may be configured, for example, with a storage device such as a RAM (Random Access Memory) or a hard disk, or a semiconductor integrated circuit equipped with a CPU (Central Processing Unit). That is, any computer capable of outputting command values, such as a calculated rotation angle, to rotation drive device 15 may be used. Rotation control device 16 may additionally include a one-chip microcomputer, a UI (User Interface) such as a keyboard or a mouse, and a network interface such as a communication device. Rotation control device 16 calculates the rotation angle of rotating shaft 12 and other parameters based on information input via the UI (User Interface) or information stored in the storage device to achieve a required antenna excitation phase, and outputs command values ​​indicating the calculated rotation angle and other parameters to rotation drive device 15 via the network interface.

[0026] Next, the operation will be described. The first wall surface 1a and the second wall surface 1b of the waveguide 1 are wide walls, and are larger in area than the walls perpendicular to the first wall surface 1a and the second wall surface 1b. Although it depends on the design specifications and the waveguide mode used, generally, in order to propagate the fundamental waveguide mode, the length of the long side of the opening forming the wide wall surface is approximately twice the length of the opening forming the narrow wall surface. In this way, a high-frequency signal is transmitted inside the waveguide 1. Furthermore, the wall surfaces 1a and 1b of the waveguide 1 are parallel to each other, and the wall surfaces may be rectangular.

[0027] The feed probe 4 extends into the waveguide 1 and is inserted parallel to the narrow wall surface, so that it is electrically coupled to the high-frequency signal (electromagnetic field component) propagating inside the waveguide 1. One end of the feed probe 4 is connected to a hollow stripline 3, which is in turn connected to the antenna drive element 2. As a result, the high-frequency signal propagating through the waveguide 1 via the feed probe 4 can be fed to the antenna drive element 2 via the hollow stripline 3, allowing the antenna element 2 to radiate electromagnetic waves into space. Note that, because each feed pin of the antenna drive element 2 is connected at a position 90° from the antenna center and is connected to the second line 11b and the third line 11c, which differ in angle by λ / 4, circularly polarized waves are radiated, and therefore this antenna operates as a circularly polarized antenna.

[0028] 2, the phase difference between the elements of the circularly polarized waves radiated from each antenna is determined by the phase difference of the current flowing through each feed probe 4 and the difference in the physical rotation angle of each antenna 4. The phase difference of the current flowing through each feed probe 4 is determined by the electromagnetic field distribution inside the waveguide 1 and the position of each antenna, and can be derived by theoretical methods or electromagnetic field analysis.

[0029] This circularly polarized antenna is configured so that the feed probe 4 is located directly below the center of the antenna drive element 2 without contacting the waveguide 1, and one end of the feed probe 4, the hollow strip line, and the antenna drive element 2 are each located in free space outside the waveguide 1. Therefore, the central axis of the antenna drive element 2 becomes the axis of rotation, and when the antenna drive element 2 and the hollow strip line 3 are rotated together to form an array antenna device, a desired phase difference between elements can be achieved.

[0030] The rotation control device 16 of the control device 14 mainly calculates the excitation phase distribution of the array antenna device in order to realize a desired radiation pattern. The excitation phase distribution of the array antenna device can be calculated, for example, from information input via a UI (User Interface) or information stored in a storage device. There are various methods for calculating the excitation phase distribution, but since these are well-known techniques, detailed explanations will be omitted. Information used to calculate the excitation phase distribution includes, for example, the frequency of the high-frequency signal, array arrangement information, the insertion length of the feed probe 4 into the waveguide 1, the desired radiation pattern, the beam scanning direction, etc.

[0031] The rotation control device 16 also calculates the rotation angle and rotation speed of the rotating shaft 12 corresponding to the excitation phase distribution, taking into account the phase difference of the current flowing through the power feed probe 4, and controls the movement of the rotating shaft 12 corresponding to the switching time of the radiation pattern of the array antenna. There are various methods for calculating the rotation angle and rotation speed of the rotating shaft 12 corresponding to the excitation phase distribution, but since these are well-known techniques, detailed description will be omitted. The rotation control device 16 outputs command values ​​indicating the calculated rotation angle and rotation speed of the rotating shaft 12 to the rotation drive device 15 via the network interface. The rotation drive device 15 generates drive currents required to rotate each rotating shaft 12 based on the command values ​​output from the rotation control device 16, and outputs the generated drive currents to each rotating device 13.

[0032] As a result, the antenna device shown in embodiment 1 functions as a circularly polarized antenna, similar to Patent Document 1, and when it is converted into an array antenna, similar to Patent Document 1, it becomes possible to realize a desired radiation pattern by using a similar control method.

[0033] <Effects of First Embodiment> The first embodiment illustrates a configuration of an antenna device including: an antenna excitation element 2; a feed pin 8b (not limiting, but an example of a first conductor portion) connected to the antenna excitation element 2 at a first position to feed power; a feed pin 8a (not limiting, but an example of a second conductor portion) connected to the antenna excitation element at a second position where the angle between the first position and the center of the antenna excitation element 2 and the angle between the second position and the center of the antenna excitation element 2 are 90 degrees and the distance from the center of the antenna excitation element 2 is equal to the distance from the center of the antenna excitation element 2 to the first position; a hollow strip line 3 (not limiting, but an example of a strip line portion) having a line 11c (not limiting, but an example of a first transmission line) connected to the feed pin 8b to feed power; and a line 11b (not limiting, but an example of a second transmission line) connected to the feed pin 8a to feed power and having a length different from that of the line 11c by a quarter wavelength of the operating frequency; and a rotating portion that rotates the antenna excitation element. The effect obtained by such a configuration is that it is possible to reduce the height of the antenna element while enabling phase control by rotation control, and therefore it is possible to make the antenna device compact.

[0034] Furthermore, in the first embodiment, the antenna excitation element 2 has a circular shape, and the rotating unit rotates the antenna excitation element 2 around the center of the antenna excitation element 2 as an axis. An effect obtained by such a configuration is that the antenna excitation element 2 can be rotated by the rotating unit more easily in a circular shape than in a rectangular shape or the like. Furthermore, by making the shape circular, it is possible to suppress variations in the microwaves irradiated from the antenna excitation element 2 depending on the angle of rotation.

[0035] In addition, in the first embodiment, the line 11c (not limiting, but an example of the first transmission line) has a part of its shape in an arc shape that follows the antenna excitation element 2, and the line 11b (not limiting, but an example of the second transmission line) has a part of its shape in an arc shape that follows the antenna excitation element 2. As an effect obtained by such a configuration, since each line has an arc shape that follows the antenna excitation element 2, it becomes easy to rotate the line 11c integrally with the antenna excitation element 2 by the rotating part.

[0036] Furthermore, in the first embodiment, the antenna device includes the feed probe 4 located on the central axis of the antenna drive element 2 and feeding power to the lines 11c and 11b, and a control unit that controls the rotation unit, and the rotation unit rotates the antenna drive element 2 around the feed probe 4 as a rotation axis under the control of the control unit. An advantage obtained from this configuration is that the rotation unit can rotate the antenna drive element 2 and the feed probe 4 located at the center of the antenna drive element 2 as a single unit, thereby maintaining operation as a circularly polarized antenna.

[0037] Furthermore, the first embodiment shows a configuration of an array antenna device including a plurality of the antenna devices described above and a control unit that controls a plurality of rotation units. The effect obtained by such a configuration is that a desired radiation pattern can be realized by controlling the rotation of the plurality of antenna devices by the control unit.

[0038] Furthermore, in this embodiment 1, the antenna excitation element 2 has a circular shape, and the hollow strip line 3 has a relatively simple structure, and can be formed using a highly productive manufacturing method such as sheet metal processing, which makes it possible to reduce manufacturing costs.

[0039] In the first embodiment, the antenna excitation element 2 has been described as having a circular patch antenna shape, but it may have other shapes, such as a square patch antenna or a patch shape with a partially cut-out configuration.

[0040] In the first embodiment, the second line 11b and the third line 11c are used as the lines forming the hollow strip line 3 to form the circularly polarized antenna. However, any configuration is acceptable as long as it can obtain circularly polarized waves and rotate around the antenna center. For the purpose of simplifying the structure and reducing costs, the third line 11c may not be formed, and a single-point feeding configuration may be used as long as the frequency specifications are met.

[0041] In the first embodiment, when forming the array antenna apparatus, the spacing of the array arrangement may be equal or may vary depending on the system requirements.

[0042] In the first embodiment, it has been stated that the second line 11b is shorter than the third line 11c by a physical length equivalent to λ / 4, but the length relationship between the second line 11b and the third line 11c may be reversed.

[0043] In the first embodiment, the first line 11a is described as being larger than the radius of the antenna excitation element 2. However, as long as the relationship in length between the second line 11b and the third line 11c is maintained, the length of the first line 11a may be shorter than the length of the antenna excitation element 2 for the purpose of further miniaturization.

[0044] Although the first embodiment shows a case where the short-circuited end 1d of the waveguide 1 is formed, the end may be open as long as impedance matching is achieved in the connection between the antenna and the waveguide 1. Also, a radio wave absorber may be disposed at the short-circuited end 1d (or the short-circuiting wall).

[0045] Although the first embodiment shows a configuration in which antennas are arranged on a linear waveguide 1, the waveguide 1 may be configured as a radial line waveguide or the like in order to simplify the waveguide 1. In this case, when forming an array antenna device, a plurality of antennas may be arranged concentrically or in a lattice pattern.

[0046] In this first embodiment, an example is shown in which three elements are arranged to form an array antenna, but the number of elements may be selected arbitrarily, such as two elements, three elements or more, in order to obtain the conditions such as beam width and antenna gain required for the system.

[0047] Although the first embodiment has been described with respect to a configuration in which the antenna drive element 2 is rotated by a rotating unit, the present embodiment is not limited to this configuration. A configuration different from the above-described embodiment may, for example and without limitation, be a configuration in which the rotating unit rotates the first feed pin 8 a and the second feed pin 8 b relative to the antenna drive element 2 around the center of the antenna drive element 2 as an axis while maintaining the positional relationship between the first feed pin 8 a and the second feed pin 8 b. If the position at which the antenna drive element 2 is fed by the feed pins is changed, the radiation phase of the antenna drive element 2 is changed without rotating the antenna drive element 2 itself. Therefore, a configuration in which the first feed pin and the second feed pin are rotated relative to the antenna drive element 2 can achieve the effects described in the above-described embodiment without rotating the antenna drive element 2.

[0048] <Embodiment 2> In the above-mentioned embodiment 1, an example was shown in which the antenna excitation element 2 was a circular patch antenna and the feed line was formed by the hollow strip line 3, but in embodiment 2, an example of a configuration using a substrate will be described. The drawings included in Fig. 3 are structural diagrams showing an antenna element according to embodiment 2 of the present invention. Fig. 3 includes Figs. 3A, 3B, 3C, and 3D. Fig. 3A is an overall perspective view, Fig. 3B is an overall side view, Fig. 3C is a top view of the antenna excitation element, and Fig. 3D is a top view of the strip line portion.

[0049] The substrate 20 has a structure in which a conductor layer such as copper is formed on both sides (a surface having a first surface and a second surface, but not limited thereto) of an insulating material 21, and is, for example, a resin substrate or a ceramic substrate. The base material used for the substrate 20 may be selected arbitrarily by the designer depending on the desired size, cost, and performance, but in the second embodiment, the thickness of the substrate 20 is set to about λ / 10. As shown in FIG. 3B , the substrate 20 is disposed on the upper wall side of the first wall surface 1a of the waveguide 1, and is electrically connected to the waveguide 1 via the probe insertion hole 5 and the feeding probe 4, as in the first embodiment. The antenna excitation element 3 is formed on the A-A' plane (an example of the second surface, but not limited thereto), and the strip line 22 is formed on the B-B' plane (an example of the first surface, but not limited thereto).

[0050] As in the first embodiment, the strip line 22 includes a first line 24a (not limiting, but an example of a transmission line) electrically connected to the first connection pad 23a, a second line 24b (not limiting, but an example of a second transmission line) electrically connected to the first line 24a, a third line 24c (not limiting, but an example of a first transmission line), a second connection pad 23b electrically connected to the second line 24b, and a third connection pad 23c electrically connected to the third line 24c. The first line 24a, the second line 24b, and the third line 24c form a power distribution circuit 25.

[0051] The substrate 20 and the power feed probe 4 are connected to one end of the power feed probe 4 and a first connection pad 23 a formed on the strip line 22 using a conductive material such as solder.

[0052] In forming the power distribution circuit 25, the length relationship between the second line 24b and the third line 24c is set to (Z+λ / 4), as shown in FIG. 3D, in order to form a circularly polarized antenna as in the first embodiment, where λ is the wavelength at the operating frequency and Z is the length of the second line 24b.

[0053] The antenna excitation element 26 is formed on the surface of the substrate 20 facing the strip line 22, and in the second embodiment, it is a circular patch as in the first embodiment.

[0054] The antenna excitation element 26 and the strip line 22 are connected using a feed pin 27 configured, for example, as a VIA (which may be a conductor or an example of a conductor, but is not limited to this). In the second embodiment, the first feed pin 27a (which may be a second conductor or an example of a second conductor, but is not limited to this) is electrically connected to the second connection pad 23b, and the second feed pin 27b (which may be a first conductor or an example of a first conductor, but is not limited to this) is electrically connected to the third connection pad 23c. In this case, the first feed pin 27a and the second feed pin 27b are positioned such that they are spaced apart by X1 from the center position of the antenna excitation element 26 and form an angle of 90° among the first feed pin 27a, the second feed pin 27b, and the center of the antenna excitation element 26.

[0055] The antenna element is configured as described above, and the rotation mechanisms and control mechanisms are the same as those in the first embodiment.

[0056] Next, the operation will be described. In the second embodiment, the antenna excitation element 26 and the strip line 22 are each formed on a substrate 20. The substrate 20 is formed of an insulating material 21 and each conductor layer, and the strip line 22 and the antenna excitation element 26 are each affected by wavelength shortening due to the insulating material 21. When wavelength shortening occurs, the strip line 22 and the antenna excitation element 26 become smaller, thereby making it possible to realize a miniaturized antenna. Furthermore, since the distance between the antenna excitation element 26 and the substrate 20 can be narrowed, the antenna can be made even lower in height.

[0057] Furthermore, unlike the first embodiment, the connection between the antenna excitation element 26 and the strip line 22 can be realized by a VIA (not limited to a VIA, but is an example of a conductor or a conductor), and the only part that needs manual connection is the connection between the feed probe 4 and the substrate 20, which reduces the number of manufacturing steps and manufacturing tolerances during mounting. Moreover, since the substrate 20 is used, the connection between the antenna excitation element 26 and the strip line 22 can be made stronger than in the first embodiment, improving the strength of the antenna itself.

[0058] In addition, since the substrate 20 does not come into contact with the upper surface of the first wall surface 1a of the waveguide 1, the entire substrate can be rotated. Therefore, it is possible to operate as a circularly polarized antenna similar to that of the first embodiment, and the effects obtained in the first embodiment are not impaired.

[0059] <Effects of Second Embodiment> This second embodiment shows a configuration of a substrate 20 including an insulating material 21 having conductor layers formed on a first surface and a second surface opposite the first surface, and a strip line 22 provided on the first surface. An effect obtained by such a configuration is that the strip line 22 is affected by wavelength shortening due to the insulating material 21. When wavelength shortening occurs, the strip line 22 becomes smaller, making it possible to realize a more compact antenna. Furthermore, the use of the substrate 20 allows for a stronger connection of the strip line 22, thereby improving the strength of the antenna itself.

[0060] In addition, in the second embodiment, the substrate 20 includes the antenna excitation element 26 provided on the second surface. As an effect obtained by such a configuration, the strip line 22 and the antenna excitation element 26 are each affected by wavelength shortening due to the insulating material 21. Wavelength shortening reduces the size of the strip line 22 and the antenna excitation element 26, thereby enabling a more compact antenna. Furthermore, the distance between the antenna excitation element 26 and the substrate 20 can be narrowed, allowing the antenna to be made even lower in height. Furthermore, the use of the substrate 20 allows the connection between the antenna excitation element 26 and the strip line 22 to be stronger than in the first embodiment, thereby improving the strength of the antenna itself.

[0061] In the second embodiment, the antenna excitation element 26 is described as having a circular patch antenna shape, but it may have other shapes, such as a square patch antenna or a patch shape with a partially cut-out configuration.

[0062] In the second embodiment, the second line 24b and the third line 24c are used as the lines forming the strip line 22 to form the circularly polarized antenna. However, any configuration is acceptable as long as it can obtain circularly polarized waves and rotate around the antenna center. If the frequency specifications are satisfied, it is also possible to use a single-point feeding configuration in which the third line 24c is not formed in order to simplify the structure, and an antenna excitation element 26 including a notch structure utilizing the degeneration effect is used.

[0063] In the second embodiment, the configuration of a single antenna element has been described, but an array antenna device may be configured using this antenna element, as in the first embodiment. When forming the array, the number of array elements and the spacing between the array elements may be set to equal spacing or different spacing depending on the system requirements.

[0064] In the second embodiment, it has been stated that the second line 24b is shorter than the third line 24c by a physical length equivalent to λ / 4, but the length relationship between the second line 24b and the third line 24c may be reversed.

[0065] In the second embodiment, the first line 24a is described as being larger than the radius of the antenna excitation element 26. However, as long as the relationship in length between the second line 24b and the third line 24c is maintained, the length of the first line 24a may be shorter than the radius of the antenna excitation element 26 for the purpose of further miniaturization.

[0066] Although the second embodiment shows a case where a short-circuited end 1d of the waveguide 1 is formed, the end may be open as long as impedance matching is achieved in the connection between the antenna and the waveguide 1. Also, a radio wave absorber may be disposed at the short-circuited end 1d.

[0067] Although the second embodiment shows a configuration in which antennas are arranged on a linear waveguide 1, the waveguide 1 may be configured as a radial line waveguide or the like in order to simplify the waveguide 1. In this case, when forming an array antenna device, a plurality of antennas may be arranged concentrically or in a lattice pattern.

[0068] In the second embodiment, the substrate 20 is described as a single-layer double-sided board, but a multi-layer board may be used to achieve a desired thickness.

[0069] <Embodiment 3> In the above-mentioned embodiment 2, a configuration in which an antenna excitation element 26 and a strip line 22 are formed on each surface of a substrate 20 was described, but in this embodiment 3, an example of a hybrid structure of embodiments 1 and 2 will be described. The drawings included in Fig. 4 are structural diagrams showing an antenna element according to embodiment 3 of the present invention. Fig. 4 includes Figs. 4A, 4B, 4C, 4D, and 4E. Fig. 4A is an overall top view, Fig. 4B is an overall side view, Fig. 4C is a top view of an antenna excitation element, Fig. 4D is a top view of a strip line portion, and Fig. 4E is a top view of a ground conductor layer.

[0070] The substrate 30 is configured with a conductor layer such as copper formed on both sides of an insulating material 31, and may be, for example, a resin substrate or a ceramic substrate. The base material used for the substrate 30 may be selected by the designer based on the desired size, cost, and performance, but in this third embodiment, the thickness of the substrate 30 is approximately λ / 10. As shown in FIG. 4B , the substrate 30 is disposed on the upper wall side of the first wall surface 1a of the waveguide 1, and is electrically connected to the waveguide 1 via the probe insertion hole 5 and the power supply probe 4, as in the second embodiment. A ground conductor 32 is formed on the CC' plane, and a strip line 33 is formed on the DD' plane.

[0071] As in the first and second embodiments, the strip line 33 includes a first line 35a (not limiting, but an example of a transmission line) electrically connected to the first connection pad 34a, a second line 35b (not limiting, but an example of a second transmission line) electrically connected to the first line 35a, a third line 35c (not limiting, but an example of a first transmission line), a second connection pad 34b electrically connected to the second line 35b, and a third connection pad 34c electrically connected to the third line 35c. The first line 35a, the second line 35b, and the third line 35c form a power distribution circuit 36.

[0072] The substrate 30 and the power feed probe 4 are connected to one end of the power feed probe 4 and a first connection pad 35 a formed on the strip line 33 using a conductive material such as solder.

[0073] In forming the power distribution circuit 36, the length relationship between the second line 35b and the third line 35c is set to (Z1+λ / 4) as shown in Fig. 4D, where λ is the wavelength at the operating frequency and Z1 is the length of the second line 35b, in order to form a circularly polarized antenna as in the first and second embodiments. Note that, unlike the first and second embodiments, in the third embodiment, the first line 35a is set shorter than the radius of the antenna excitation element 39.

[0074] The antenna excitation element 39 is a circular patch, as in the first embodiment, and is disposed on the upper surface side of the ground conductor 32 formed on the substrate 30 .

[0075] The antenna excitation element 39 and the strip line 33 are connected via a first feed pin 38a (not limited to, an example of a second conductor or a second conductor) and a second feed pin 38b (not limited to, an example of a first conductor or a first conductor) inserted into a first VIA 37a and a second VIA 37b formed on the substrate 30, respectively. In the third embodiment, the first VIA 37a is electrically connected to the second connection pad 34b, and the second VIA 37b is electrically connected to the third connection pad 34c. In this case, the first VIA 37a and the second VIA 37b are positioned such that they are spaced apart by X2 from the center position of the antenna excitation element 39 and form an angle of 90° with the first VIA 37a, the second VIA 37b, and the center of the antenna excitation element 39. After being inserted into the VIA 37, the power supply pin 38 is fixed using a conductive material such as solder.

[0076] The antenna element is configured as described above, and the rotation mechanisms and control mechanisms are the same as those in the first embodiment.

[0077] Next, the operation will be described. In the third embodiment, unlike the second embodiment, the antenna excitation element 39 and the strip line 33 are not formed on the same substrate, but the antenna excitation element 39 is located outside the substrate 30. The substrate 30 is formed by the insulating material 31 and each conductor layer, and the strip line 33 functions as a microstrip line, so that the antenna excitation element 39 is more susceptible to wavelength shortening than in the second embodiment. Since the strip line 33 and the antenna excitation element 39 are configured independently, the power distribution circuit 36 ​​and other components formed by the strip line 33 can be placed directly below the antenna excitation element 39. Since the desired impedance can be achieved with an insulating material 31 thickness of approximately several hundred microns, the antenna can be made lower in height than in the first embodiment. In addition to the fact that the wiring length is basically shorter, the absence of a lossy material such as an insulating material between the antenna excitation element 39 and the ground conductor 32 reduces loss due to the antenna feed circuit and dielectric loss of the insulating material, enabling an improvement in the antenna's operating gain compared to the second embodiment.

[0078] Furthermore, unlike the first embodiment, a hybrid structure of a substrate structure and a hollow structure is used, which improves the strength of the strip line portion, resulting in a strength that is greater than that of the first embodiment.

[0079] As in the second embodiment, the substrate 30 does not come into contact with the waveguide 1 on the upper surface of the first wall surface 1a of the waveguide 1, and therefore the entire substrate can be rotated. This allows operation as a circularly polarized antenna similar to that of the first embodiment, and does not impair the effects obtained in the first and second embodiments.

[0080] <Effects of Third Embodiment> In the third embodiment, the substrate 30 is installed with a space provided between it and the antenna excitation element 39. An effect obtained by such a configuration is that, since no lossy material such as an insulating material is interposed between the antenna excitation element 39 and the substrate 30, loss due to the power feeding circuit to the antenna and dielectric loss of the insulating material can be reduced, and the working gain of the antenna can be improved more than in the second embodiment.

[0081] In the third embodiment, the antenna excitation element 39 has been described as having a circular patch antenna shape, but it may have other shapes, such as a square patch antenna or a patch shape with a partially cut-out configuration.

[0082] In this third embodiment, the second line 35b and the third line 35c are used as the lines forming the strip line 33 to form the circularly polarized antenna. However, any configuration is acceptable as long as it can obtain circularly polarized waves and rotate around the antenna center. If the frequency specifications are satisfied, it is also possible to use a single-point feeding configuration in which the third line 35c is not formed in order to simplify the structure, and an antenna excitation element 39 including a notch structure utilizing the degeneration effect is used.

[0083] In the third embodiment, the configuration of a single antenna element has been described, but an array antenna device may be configured using this antenna element, as in the first and second embodiments. When forming the array, the number of array elements and the spacing between the array elements may be set to equal spacing or different spacing depending on the system requirements.

[0084] In the third embodiment, it has been described that the second line 35b is shorter than the third line 35c by a physical length equivalent to λ / 4, but the length relationship between the second line 35b and the third line 35c may be reversed.

[0085] Although the third embodiment shows a case where a short-circuited end 1d of the waveguide 1 is formed, the end may be open as long as impedance matching is achieved in the connection between the antenna and the waveguide 1. Also, a radio wave absorber may be disposed at the short-circuited end 1d.

[0086] Although the third embodiment shows a configuration in which antennas are arranged on a linear waveguide 1, the waveguide 1 may be configured as a radial line waveguide or the like in order to simplify the waveguide 1. In this case, when forming an array antenna device, a plurality of antennas may be arranged concentrically or in a lattice pattern.

[0087] In the second embodiment, the substrate 20 is described as a single-layer double-sided board, but a multi-layer board may be used to achieve a desired thickness.

[0088] In the third embodiment, the antenna excitation element 39 is located in free space, and the strip line 33 is formed on the substrate 30. This allows all of the strip lines 33 to be arranged directly below the antenna excitation element 39, and also facilitates component mounting on the substrate 30. Therefore, the power distribution circuit 36 ​​may be replaced with a branch line coupler. This replacement has the effect of improving inter-element isolation when the antenna of the third embodiment is used in an array antenna. However, as long as isolation can be guaranteed, configurations other than branch line couplers, such as a Wilkinson power combining circuit or a rat race coupler, may also be used. Alternatively, since component mounting is also possible, high-frequency components such as an isolator or a circulator may be installed to reinforce isolation.

[0089] <Embodiment 4> In embodiments 1 to 3, we have described the features of the antenna device, but in this embodiment 4, we will show an example of the structure of a microwave heating device using the antenna device shown in embodiments 1 to 3.

[0090] Fig. 5 shows an example of a microwave heating device according to the fourth embodiment. The fourth embodiment has a structure relating to a system that radiates electromagnetic waves into a closed space such as a metal housing 40, rather than antenna radiation into free space. A specific example would be a microwave oven.

[0091] The metal housing 40 is a box made of metal such as aluminum, and is formed by metal cutting or sheet metal processing. Although the fourth embodiment is described as rectangular, it may be cylindrical or have rounded corners depending on the application and manufacturing method. The top cover may be formed separately, but in the case of FIG. 5 , it is configured to have a thickness that fits the waveguide 1, and the first wall surface 1 a of the waveguide 1 serves as the top cover of the metal housing 40.

[0092] The antenna 41 is an array antenna device, employing the antenna devices shown in the first to third embodiments. The reason for this is to focus the beam at a desired position, as will be described later. Although three elements are shown in Fig. 5, the number of elements may be changed taking into consideration the size of the metal housing 40 and the antenna 41, as well as the cost and beam concentration.

[0093] The heated object 42 and the non-heated object 43 are assumed to be, for example, insulating materials such as food or plastic, and the heated object 42 and the non-heated object 43 may be made of the same material or different materials. The heated object 42 here is defined as an object that generates heat by causing beam loss due to loss terms (conductivity and dielectric tangent) of the insulating material at the focal point where the beam is focused by the array antenna formed by the antenna 41.

[0094] As shown in the first to third embodiments, the antennas 41 are fed by the waveguide 1 (waveguide). In the case of Fig. 5, a series feeding configuration is shown, but depending on the situation, power may be fed to each antenna 41 by a radial line waveguide or a tournament structure waveguide. The input end 1c of the waveguide 1 is a power source such as a magnetron, and high output power can be fed to each antenna 41.

[0095] Next, the operation will be described. In the fourth embodiment, an array antenna device using the antenna devices shown in the first to third embodiments is arranged in a closed space. The antenna devices shown in the first to third embodiments basically have a lower-profile antenna 41 compared to Patent Document 1. Therefore, the distance between the object 42 and the antenna 41 is generally greater than that of Patent Document 1, enabling it to function as a far-field radiator. The far-field radiator improves the beam focusing accuracy, enabling more spot heating of the object 42. Since the antenna 41 is made up of the antenna device shown in the first to third embodiments, the excitation phase of the antenna 41 can be changed by rotating the antenna. Therefore, the antenna rotation angle can be changed depending on the position of the object 42, the dielectric constant, and other factors. This reduces uneven heating, which occurs in conventional microwave ovens, and enables selective heating of individual objects, thereby enabling efficient heating.

[0096] As is clear from the above, the microwave heating device according to this embodiment 4 not only enables efficient heating, but also realizes the advantages of an antenna device, such as low cost, improved manufacturability, and compact size, thereby achieving high functionality as a system.

[0097] In the microwave heating device according to the fourth embodiment, a radio wave absorber 45 may be attached as shown in Fig. 6 in order to reduce the influence of multiple reflections within the metal casing. In this case, although Fig. 6 shows a configuration in which the radio wave absorber 45 is attached to all surfaces except the top surface, it may also be attached only to the bottom surface.

[0098] The microwave heating device according to the fourth embodiment may be equipped with a sensor 46 to enable, for example, electromagnetic field monitoring or temperature monitoring, by changing the rotation angle of the antenna 41 in real time to achieve more efficient heating. As shown in FIG. 7 , the sensor 46 is installed in the metal housing via a through-hole provided in the metal housing. The sensor 46 may also be configured such that a conductor connected to the sensor 46 via the through-hole is connected to a monitor 47. The monitor 47 is capable of displaying information transmitted from the sensor 46. Information from the sensor 46 may be transmitted to the rotation control device 16 via a feedback system 48, and the rotation control device 16 may be configured to control the rotation based on the information from the sensor 46. The sensor 46 does not necessarily have to be connected to the monitor 47 or the like via a wire. The sensor 46 may communicate with the monitor 47 via a communication unit or the like installed inside the sensor 46, and the information detected by the sensor 46 may be transmitted to the monitor 47.

[0099] In addition, the microwave heating device according to this embodiment 4 has been described as being configured to use the antenna device shown in embodiments 1 to 3, but other antenna configurations such as a helical antenna may be used as long as problems such as manufacturing issues and cost can be solved.

[0100] Various aspects of the present disclosure are summarized below as appendices.

[0101] (Supplementary Note 1) An antenna device comprising: an antenna excitation element; a first conductor connected to the antenna excitation element at a first position to feed power; a second conductor connected to the antenna excitation element at a second position, where an angle formed by the first position and a center of the antenna excitation element and a second position different from the first position and the center of the antenna excitation element is 90 degrees and the distance from the center of the antenna excitation element is equal to the distance from the center of the antenna excitation element to the first position; a strip line section having a first transmission line connected to the first conductor to feed power and a second transmission line connected to the second conductor to feed power, the second transmission line having a length different from that of the first transmission line by ¼ wavelength of an operating frequency; and a rotating part that rotates the antenna excitation element. (Supplementary Note 2) The antenna device according to Supplementary Note 1, wherein the antenna excitation element is circular in shape, and the rotating part rotates the antenna excitation element around the center of the antenna excitation element as an axis. (Supplementary Note 3) The antenna device according to Supplementary Note 2, wherein a portion of the first transmission line has an arc shape that follows the antenna excitation element, and a portion of the second transmission line has an arc shape that follows the antenna excitation element. (Supplementary Note 4) The antenna device according to any one of Supplementary Notes 1 to 3, wherein the antenna device comprises a substrate including an insulating material having conductor layers formed on a first surface and a second surface opposite to the first surface, and the strip line portion provided on the first surface. (Supplementary Note 5) The antenna device according to Supplementary Note 4, wherein the substrate includes the antenna excitation element provided on the second surface. (Supplementary Note 6) The antenna device according to Supplementary Note 4, wherein the substrate is installed with a space provided between it and the antenna excitation element. (Supplementary Note 7) The antenna device according to any one of Supplementary Notes 1 to 6, further comprising: a feed probe located on a central axis of the antenna excitation element and feeding power to the first transmission line and the second transmission line; and a control unit that controls the rotation unit, wherein the rotation unit rotates the antenna excitation element around the feed probe as a rotation axis under the control of the control unit. (Supplementary Note 8) The antenna device according to Supplementary Note 7, further comprising: a waveguide that has a hole into which the feed probe is inserted and that feeds power to the feed probe.(Supplementary Note 9) The antenna device according to Supplementary Note 8, wherein the waveguide is a rectangular waveguide, the rectangular waveguide having two wide wall surfaces and two narrow wall surfaces each having an area equal to or smaller than the wide wall surfaces, the wide wall surfaces having a first wall surface and a second wall surface. (Supplementary Note 10) The antenna device according to Supplementary Note 8, wherein the waveguide is a radial line waveguide. (Supplementary Note 11) The antenna device according to Supplementary Note 8, wherein the waveguide has wall surfaces which are rectangular flat plates, and is a parallel plate waveguide. (Supplementary Note 12) The antenna device according to Supplementary Note 9, wherein the waveguide has short-circuiting walls at its ends. (Supplementary Note 13) The antenna device according to Supplementary Note 10 or Supplementary Note 11, wherein the waveguide has short-circuiting walls on its side walls. (Supplementary Note 14) The antenna device according to Supplementary Note 12 or Supplementary Note 13, wherein the waveguide has short-circuiting walls on its side walls. (Supplementary Note 15) The antenna device according to any one of Supplementary Note 1 to Supplementary Note 14, wherein the antenna formed on the antenna excitation element is a circularly polarized antenna. (Supplementary Note 16) An array antenna device comprising a plurality of the antenna devices according to Supplementary Note 1 and a control unit that controls a plurality of the rotating units. (Supplementary Note 17) A microwave heating device comprising: a metal housing with a hollowed-out top surface, the array antenna device according to Supplementary Note 16, and a waveguide that feeds power to the array antenna device according to Supplementary Note 16, wherein the antenna excitation element is disposed on the top surface of the metal housing so as to face the bottom side of the metal housing, and a wall surface of the waveguide serves as a top cover of the metal housing. (Supplementary Note 18) The microwave heating device according to Supplementary Note 17, wherein the metal housing has a radio wave absorber on its inner wall surface. (Supplementary Note 19) The microwave heating device according to Supplementary Note 17 or Supplementary Note 18, wherein a sensor is provided in the metal housing, and the control unit controls the plurality of rotating units based on information detected by the sensor.

[0102] The antenna device and microwave heating device using the same according to the present disclosure are suitable for various antenna devices that do not require switching speeds at electronic levels, and are particularly suitable for microwave heating devices that require low cost and a certain level of strength, such as household microwave ovens.

[0103] REFERENCE SIGNS LIST 1 Waveguide 1a First wall surface 1b Second wall surface 1c Input end 1d Short-circuit end 2 Antenna excitation element 3 Hollow strip line 4 Feeding probe 5 Probe insertion hole 6 Connection shaft 7 Connection shaft insertion hole 8 Feeding pin 8a First feeding pin 8b Second feeding pin 9 Connection pad (hollow strip line) 9a First connection pad 9b Second connection pad 9c Third connection pad 10 Power distribution circuit 11 Feeding line using hollow strip line 11a First line 11b Second line 11c Third line 12 Rotating shaft 13 Rotating device 14 Control device 15 Rotation drive device 16 Rotation control device 20 Substrate 21 Insulating material 22 Strip line 23 Connection pad (strip line) 23a First connection pad 23b Second connection pad 23c Third connection pad 24 Feed line using strip line 24a First line 24b Second line 24c Third line 25 Power distribution circuit 26 Antenna excitation element 27 Feed pin 27a First feed pin 27b Second feed pin 30 Substrate 31 Insulating material 32 Ground conductor 33 Strip line 34 Connection pad (Embodiment 3) 34a First connection pad 34b Second connection pad 34c Third connection pad 35 Feed line using strip line 35a First line 35b Second line 35c Third line 36 Power distribution circuit 37 VIA 37a First VIA 37b Second VIA 38 Feed pin 38a First feed pin 38b Second feed pin 39 Antenna excitation element 40 Metal housing 41 Antenna 42 Heated object 43 Non-heated object 44 Power supply 45 Radio wave absorber 46 Sensor (e.g., infrared sensor) 47 Monitor 48 Feedback system

Claims

1. An antenna device comprising: an antenna excitation element; a first conductor portion connected to the antenna excitation element at a first position to feed power; a second conductor portion connected to the antenna excitation element at a second position where the angle between the first position and the center of the antenna excitation element and the angle between a second position different from the first position and the center of the antenna excitation element are 90 degrees and the distance from the center of the antenna excitation element is equal to the distance from the center of the antenna excitation element to the first position; a strip line portion having a first transmission line connected to the first conductor portion to feed power and a second transmission line connected to the second conductor portion to feed power, the second transmission line having a length different from that of the first transmission line by 1 / 4 wavelength of the operating frequency; and a rotating portion for rotating the antenna excitation element.

2. The antenna device according to claim 1, wherein the antenna excitation element is circular in shape, and the rotating part rotates the antenna excitation element around the center of the antenna excitation element as an axis.

3. The antenna device according to claim 2, characterized in that a portion of the first transmission path is arc-shaped along the antenna excitation element, and a portion of the second transmission path is arc-shaped along the antenna excitation element.

4. An antenna device as described in any one of claims 1 to 3, characterized in that it comprises a substrate including an insulating material having a conductor layer formed on a first surface and a second surface opposite the first surface, and the strip line portion provided on the first surface.

5. The antenna device according to claim 4, wherein the substrate includes the antenna excitation element provided on the second surface.

6. The antenna device according to claim 4, wherein the substrate is installed with a space provided between it and the antenna excitation element.

7. An antenna device according to any one of claims 1 to 6, characterized in that it comprises a feeding probe located on the central axis of the antenna excitation element and feeding power to the first transmission line and the second transmission line, and a control unit that controls the rotating unit, wherein the rotating unit rotates the antenna excitation element around the feeding probe as a rotation axis under the control of the control unit.

8. The antenna device according to claim 7, further comprising: a waveguide having a hole into which the feed probe is inserted and for feeding power to the feed probe.

9. The antenna device according to claim 8, wherein the waveguide is a rectangular waveguide, the rectangular waveguide has two wide wall surfaces and two narrow wall surfaces whose areas are equal to or smaller than those of the wide wall surfaces, and the wide wall surfaces have a first wall surface and a second wall surface.

10. The antenna device according to claim 8, wherein the waveguide is a radial line waveguide.

11. The antenna device according to claim 8, wherein the waveguide has rectangular flat plate walls and is a parallel plate waveguide.

12. The antenna device according to claim 9, wherein the waveguide has a short-circuit wall at an end thereof.

13. The antenna device according to claim 10 or 11, characterized in that the waveguide has a short-circuit wall on its side wall.

14. The antenna device according to claim 12 or 13, wherein the short-circuiting wall has a radio wave absorber.

15. An antenna device according to any one of claims 1 to 14, characterized in that the antenna formed on the antenna excitation element is a circularly polarized antenna.

16. An array antenna device comprising a plurality of the antenna devices according to claim 1 and a control unit for controlling a plurality of the rotating units.

17. A microwave heating device comprising: a metal housing with a hollowed-out top surface; an array antenna device as defined in claim 16; and a waveguide for feeding power to the array antenna device as defined in claim 16, wherein the antenna excitation element is arranged on the top surface of the metal housing so as to face the bottom surface of the metal housing; and the wall surface of the waveguide forms the top cover of the metal housing.

18. The microwave heating device according to claim 17, wherein the metal housing has a radio wave absorber on the inner wall surface.

19. A microwave heating device as described in claim 17 or claim 18, characterized in that it is provided with a sensor arranged inside the metal casing, and the control unit controls the plurality of rotating units based on information detected by the sensor.

Images