Double-resonant antenna

Abstract

To provide an antenna having a structure that resonates at multiple operating frequencies. [Solution] The double-resonant antenna 10 comprises a main antenna 30 and an additional radiating element 270. The main antenna 30 comprises a closed ring-shaped main section 320 and a feeding section 210. The feeding section 210 has a first feeding section 220, a second feeding section 250, a first feeding point 2421, and a second feeding point 252. The first feeding section 220 and the second feeding section 250 each extend outward from the main section 320. The first feeding point 2421 is provided in the first feeding section 220. The second feeding point 252 is provided in the second feeding section 250. The additional radiating element 270 extends directly from the first feeding section 220 outward from the main antenna 30.

Description

Technical Field

[0001] The present invention relates to a multiple resonance antenna.

Background Art

[0002] Patent Document 1 discloses a small and broadband antenna 900. As shown in FIG. 10, the antenna 900 of Patent Document 1 has a split ring resonator 910 using a split ring 920 which is an annular conductor having a split portion 922. Specifically, the antenna 900 of Patent Document 1 has a main portion 930 constituting the split ring 920 and a feeding portion 940. Here, the feeding portion 940 is provided in the main portion 930.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The antenna 900 of Patent Document 1 operates at the resonance frequency of the split ring resonator 910. That is, the antenna 900 of Patent Document 1 resonates only at a single operating frequency and cannot cope with a wide frequency band.

[0005] Therefore, an object of the present invention is to provide an antenna having a structure that resonates at a plurality of operating frequencies.

Means for Solving the Problems

[0006] As a first multiple resonance antenna, the present invention is a multiple resonance antenna including a main antenna and an additional radiation element, wherein the main antenna includes a closed ring-shaped main portion and a feeding portion, The power supply unit has a first power supply section, a second power supply section, a first power supply point, and a second power supply point. The first power supply section and the second power supply section each extend outward from the main section, The first power supply point is provided in the first power supply area, The second power supply point is provided in the second power supply area, The additional radiating element extends directly from the first feeding point toward the outside of the main antenna. We provide a double-resonant antenna.

[0007] Furthermore, the present invention provides a second double-resonant antenna, which is a first double-resonant antenna. The first power supply portion has a first portion extending from the main portion in a first predetermined direction, and a second portion extending from the first portion in a second predetermined direction intersecting the first predetermined direction. The second portion has a first segment extending from the first portion and a second segment extending from the first segment. In the aforementioned second predetermined direction, the center of the second portion is located between the first segment and the second segment. In the second predetermined direction, the first power supply point is provided at the end of the second segment, The second power supply section extends from the main section to the second power supply point, The additional radiating element extends from the second segment. We provide a double-resonant antenna.

[0008] Furthermore, the present invention provides a third double-resonant antenna, which is a second double-resonant antenna, The second portion has a straight section that extends linearly in the second predetermined direction, The additional radiating element has an additional linear portion that extends linearly in the second predetermined direction, The aforementioned straight section and the aforementioned additional straight section are parallel to each other and constitute an open slot with one end open. We provide a double-resonant antenna.

[0009] Furthermore, the present invention provides a fourth double-resonant antenna, which is a first double-resonant antenna, The first power supply portion has a first portion extending from the main portion in a first predetermined direction, and a second portion extending from the first portion in a second predetermined direction intersecting the first predetermined direction. The second portion has a first segment extending from the first portion and a second segment extending from the first segment. In the aforementioned second predetermined direction, the center of the second portion is located between the first segment and the second segment. In the second predetermined direction, the first power supply point is provided at the end of the second segment, The second power supply section extends from the main section to the second power supply point, The additional radiating element extends from the first segment. We provide a double-resonant antenna.

[0010] Furthermore, the present invention also provides a fifth double-resonant antenna, which is a fourth double-resonant antenna, The double-resonant antenna further includes an extension extending from the second feeding point in the first predetermined direction, and a stub extending from the extension toward the additional radiating element in a third predetermined direction opposite to the second predetermined direction. The stub is positioned spaced apart from the second portion in the first predetermined direction. We provide a double-resonant antenna.

[0011] Furthermore, the present invention also provides a sixth double-resonant antenna, which is a fourth double-resonant antenna, The second power supply portion has a third portion extending from the main portion in a first predetermined direction, and a fourth portion extending from the third portion toward the additional radiating element in a third predetermined direction opposite to the second predetermined direction. The fourth portion is spaced apart from the second portion in the first predetermined direction. We provide a double-resonant antenna.

[0012] Also, the present invention provides a seventh complex resonance antenna, which is a first complex resonance antenna, where the complex resonance antenna further includes an auxiliary radiation element extending from the second power supply portion toward the outside of the main antenna. A complex resonance antenna is provided.

Advantages of the Invention

[0013] The complex resonance antenna of the present invention includes, in addition to the main antenna, an additional radiation element. As a result, the complex resonance antenna of the present invention can resonate at both the operating frequency of the main antenna and the operating frequency of the additional radiation element. That is, the complex resonance antenna of the present invention has a structure that resonates at a plurality of operating frequencies.

Brief Description of the Drawings

[0014] [Figure 1] It is a top view showing a complex resonance antenna according to an embodiment of the present invention. [Figure 2] It is a top view showing a first modification of the complex resonance antenna of FIG. 1. [Figure 3] It is a top view showing a second modification of the complex resonance antenna of FIG. 1. [Figure 4] It is a top view showing a third modification of the complex resonance antenna of FIG. 1. [Figure 5] It is a top view showing a fourth modification of the complex resonance antenna of FIG. 1. [Figure 6] It is a top view showing a fifth modification of the complex resonance antenna of FIG. 1. [Figure 7] It is a top view showing a sixth modification of the complex resonance antenna of FIG. 1. [Figure 8] It is a top view showing a seventh modification of the complex resonance antenna of FIG. 1. [Figure 9] It is a top view showing an eighth modification of the complex resonance antenna of FIG. 1. [Figure 10] It is a top view showing the antenna described in Patent Document 1.

Embodiments for Carrying Out the Invention

[0015] As shown in Figure 1, the double-resonant antenna 10 according to an embodiment of the present invention comprises a main antenna 30 and an additional radiating element 270. Note that the double-resonant antenna 10 in this embodiment does not have a ground conductor around it.

[0016] As shown in Figure 1, the main antenna 30 and the additional radiating element 270 are located on the same plane perpendicular to the vertical direction. In this embodiment, the vertical direction is the Z direction. Also, the +Z direction is upward and the -Z direction is downward. In the double-resonant antenna 10, the main antenna 30 and the additional radiating element 270 are integrally formed. The combination of the main antenna 30 and the additional radiating element 270 is made up of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited to this, and the combination of the main antenna 30 and the additional radiating element 270 may be made up of, for example, a metal member mounted on the substrate during use. Furthermore, when the main antenna 30 and the additional radiating element 270 are constructed by microfabrication, it is more preferable to construct them as a conductive pattern formed on a substrate because it is superior in terms of mechanical strength.

[0017] Referring to Figure 1, the main antenna 30 is a resonant antenna and has an operating frequency (resonant frequency) determined by its shape and size. The main antenna 30 comprises a closed ring-shaped main section 320 and a feed section 210.

[0018] As shown in Figure 1, the shape of the main part 320 in this embodiment is a substantially rectangular annular shape that is elongated in the lateral direction. However, the present invention is not limited to this. The shape of the main part 320 of the present invention may be not only a substantially rectangular annular shape, but also various annular shapes such as a ring shape, an elliptical annular shape, or a polygonal annular shape. In this embodiment, the lateral direction is the X direction. In this embodiment, the -X direction may be specifically referred to as the first predetermined direction.

[0019] As shown in Figure 1, the main part 320 has a first part 330, a second part 334, a third part 336, and a fourth part 338. The first part 330 and the third part 336 each extend in the lateral direction. The first part 330 and the third part 336 are separated from each other in the front-rear direction. The first part 330 and the third part 336 are arranged parallel to each other. The second part 334 and the fourth part 338 each extend in the front-rear direction. The second part 334 and the fourth part 338 are separated from each other in the lateral direction. The second part 334 and the fourth part 338 are arranged parallel to each other. In this embodiment, the front-rear direction is the Y direction. The +Y direction is forward, and the -Y direction is backward. In this embodiment, the -Y direction may be specifically referred to as the second predetermined direction, and the +Y direction may be specifically referred to as the third predetermined direction.

[0020] As shown in Figure 1, the first part 330 is located on the first predetermined direction side of the second part 334. The third part 336 is located on the second predetermined direction side of the first part 330. The fourth part 338 is located on the first predetermined direction side of the second part 334. The second part 334 connects the first part 330 and the third part 336. The fourth part 338 connects the first part 330 and the third part 336.

[0021] As shown in Figure 1, the power supply unit 210 is provided so as to extend outward from the main unit 320. The power supply unit 210 is located on the first predetermined direction side (-X side) of the main unit 320. However, the present invention is not limited thereto, and the power supply unit 210 may be located on a side other than the -X side of the main unit 320. The power supply unit 210 has a first power supply section 220, a second power supply section 250, a first power supply point 2421, and a second power supply point 252.

[0022] As shown in Figure 1, the first power supply section 220 extends outward from the main section 320. The first power supply section 220 extends from the main section 320 to the first power supply point 2421. The first power supply section 220 has a first section 230 and a second section 240.

[0023] As shown in Figure 1, the first portion 230 extends from the main portion 320 in a first predetermined direction. That is, the first portion 230 extends linearly from the main portion 320 in a first predetermined direction. However, the present invention is not limited thereto, and the first portion 230 may have any shape as long as it extends from the main portion 320 in a first predetermined direction. The first portion 230 is located in the same position as the first portion 330 in the front-rear direction. The first portion 230 is located on the first predetermined direction side of the first portion 330.

[0024] As shown in Figure 1, the second portion 240 extends from the first portion 230 in a second predetermined direction intersecting the first predetermined direction. That is, the second portion 240 extends from the first portion 230 in a second predetermined direction perpendicular to the first predetermined direction. The second portion 240 extends from the end of the first portion 230 in the first predetermined direction in the second predetermined direction. The second portion 240 has a linear portion 2422 that extends linearly in the second predetermined direction. More specifically, the second portion 240 is composed only of a linear portion 2422 that extends linearly in the second predetermined direction. However, the present invention is not limited thereto, and the second portion 240 may have any shape as long as it extends from the first portion 230 in the second predetermined direction.

[0025] As shown in Figure 1, the second portion 240 has a first segment 241 and a second segment 242.

[0026] As shown in Figure 1, the first segment 241 extends from the first portion 230. That is, the first segment 241 extends linearly from the first portion 230 in a second predetermined direction. The first segment 241 extends linearly from the end of the first portion 230 in a first predetermined direction in a second predetermined direction.

[0027] As shown in Figure 1, the second segment 242 extends from the first segment 241. That is, the second segment 242 extends linearly from the first segment 241 in a second predetermined direction. In the second predetermined direction, the center 245 of the second portion 240 is located between the first segment 241 and the second segment 242. That is, in the second predetermined direction, the center 245 of the second portion 240 is located at the boundary between the first segment 241 and the second segment 242.

[0028] As shown in Figure 1, the second power supply section 250 extends outward from the main section 320. The second power supply section 250 extends from the main section 320 to the second power supply point 252. That is, the second power supply section 250 extends linearly from the main section 320 to the second power supply point 252 in a first predetermined direction. The second power supply section 250 is located in the same position as the third section 336 in the front-rear direction. The second power supply section 250 is located on the first predetermined direction side of the third section 336.

[0029] As shown in Figure 1, the first power supply point 2421 is located in the first power supply section 220. In a second predetermined direction, the first power supply point 2421 is located at the end of the second section 240. More specifically, in the second predetermined direction, the first power supply point 2421 is located at the end of the second segment 242. An excitation source 40 is connected to the first power supply point 2421. Specifically, the core wire (not shown) of a coaxial cable (not shown) is connected to the first power supply point 2421.

[0030] As shown in Figure 1, the second power supply point 252 is located in the second power supply section 250. The excitation source 40 is connected to the second power supply point 252. Specifically, the outer conductor (not shown) of the coaxial cable is connected to the second power supply point 252.

[0031] As shown in Figure 1, the additional radiating element 270 extends directly from the feed point 210 toward the outside of the main antenna 30. The additional radiating element 270 extends toward the outside of the feed point 210. The additional radiating element 270 extends from the feed point 210 in a first predetermined direction. The additional radiating element 270 extends directly from the first feed point 220 toward the outside of the main antenna 30. The additional radiating element 270 extends from the first feed point 220 in a first predetermined direction.

[0032] As shown in Figure 1, the additional radiating element 270 extends from the second segment 242, which includes the first feed point 2421. This configuration allows the additional radiating element 270 to extend from the vicinity of the first feed point 2421, making impedance matching easier.

[0033] As shown in Figure 1, the additional radiating element 270 has an additional linear portion 272 that extends linearly in a second predetermined direction. The linear portion 2422 and the additional linear portion 272 are located apart from each other in the lateral direction. The linear portion 2422 and the additional linear portion 272 are parallel to each other and constitute an open slot 260 with one end open. This makes impedance matching easier for the additional radiating element 270. The end of the open slot 260 on the third predetermined direction side is open. It is preferable that the length of the open slot 260 in the second predetermined direction is longer, as this makes impedance matching of the additional radiating element 270 easier.

[0034] As shown in Figure 1, the additional radiating element 270 has a base portion 271 and a first extension portion 274. The base portion 271 extends from the second segment 242 in a first predetermined direction. That is, the base portion 271 extends linearly from the second segment 242 in a first predetermined direction. The base portion 271 and the first extension portion 274 are connected by an additional linear portion 272. The additional linear portion 272 extends from the base portion 271 in a third predetermined direction. The first extension portion 274 extends from the additional linear portion 272 in a first predetermined direction. That is, the first extension portion 274 extends linearly from the additional linear portion 272 in a first predetermined direction. The first extension portion 274 is a rectangle with its longitudinal side in the transverse direction. However, the present invention is not limited thereto, and the shape of the first extension portion 274 is not limited to a rectangle; it may have a stub at its tip.

[0035] The additional radiating element 270 in this embodiment had a base portion 271, an additional linear portion 272, and a first extension portion 274, but the present invention is not limited thereto. The additional radiating element 270 may consist only of a first extension portion 274 that extends directly from the second segment 242, without having a base portion 271 and an additional linear portion 272.

[0036] The length and shape of the additional radiating element 270 are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequency of the main antenna 30.

[0037] As can be seen from Figure 1, in the double-resonant antenna 10, the main antenna 30 is fed from a first feed point 2421 and a second feed point 252. The additional radiating element 270 is connected to the feed point 210. With this configuration, the main antenna 30 operates as the first resonant section, and the additional radiating element 270 operates as a second resonant section different from the first resonant section. The first and second resonant sections have different resonant frequencies. Thus, the double-resonant antenna 10 of this embodiment has a structure that electrically resonates at two operating frequencies: the operating frequency of the main antenna (first resonant section) 30 and the operating frequency of the additional radiating element (second resonant section) 270.

[0038] Embodiments of the present invention have been described so far, but these embodiments may be modified as follows.

[0039] (Variation 1) As shown in Figure 2, the first modified example of the double-resonant antenna 10A comprises a main antenna 30A and an additional radiating element 270A. Note that this modified example of the double-resonant antenna 10A does not have a ground conductor around it.

[0040] As shown in Figure 2, the main antenna 30A and the additional radiating element 270A are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10A, the main antenna 30A and the additional radiating element 270A are integrally formed. The combination of the main antenna 30A and the additional radiating element 270A is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30A and the additional radiating element 270A may be composed of, for example, a metal member mounted on the substrate during use.

[0041] As shown in Figure 2, the main antenna 30A comprises a closed ring-shaped main section 320 and a feed section 210A. Here, the main section 320 is the same as the main section 320 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0042] As shown in Figure 2, the power supply section 210A is provided so as to extend outward from the main section 320. The power supply section 210A is located on the first predetermined direction side (-X side) of the main section 320. However, the present invention is not limited thereto, and the power supply section 210A may be located on a side other than the -X side of the main section 320. The power supply section 210A has a first power supply section 220A, a second power supply section 250A, a first power supply point 2421, and a second power supply point 252. Here, the first power supply point 2421 and the second power supply point 252 are the same as the first power supply point 2421 and the second power supply point 252 of the double-resonant antenna 10 in the above-described embodiment, and a detailed explanation thereof is omitted.

[0043] As shown in Figure 2, the first feeding section 220A extends from the main section 320 to the first feeding point 2421. The first feeding section 220A has a first section 230 and a second section 240A. Here, the first section 230 is the same as the first section 230 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0044] As shown in Figure 2, the second portion 240A extends from the first portion 230 in a second predetermined direction intersecting the first predetermined direction. That is, the second portion 240A extends from the first portion 230 in a second predetermined direction perpendicular to the first predetermined direction. The second portion 240A extends from the end of the first portion 230 in the first predetermined direction in the second predetermined direction. In the second predetermined direction, the first power supply point 2421 is provided at the end of the second portion 240A. The second portion 240A has a straight section 2422 extending linearly in the second predetermined direction and an extension section 244. The extension section 244 extends from the straight section 2422 in the first predetermined direction. That is, the extension section 244 extends linearly from the straight section 2422 in the first predetermined direction.

[0045] As shown in Figure 2, the second portion 240A has a first segment 241 and a second segment 242A. Here, the first segment 241 is the same as the first segment 241 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0046] As shown in Figure 2, the second segment 242A extends from the first segment 241. More specifically, the second segment 242A extends linearly from the first segment 241 in a second predetermined direction, then bends and extends linearly in the first predetermined direction. In the second predetermined direction, the center 245A of the second portion 240A is located between the first segment 241 and the second segment 242A. That is, in the second predetermined direction, the center 245A of the second portion 240A is located at the boundary between the first segment 241 and the second segment 242A. In the second predetermined direction, the first power supply point 2421 is provided at the end of the second segment 242A.

[0047] As shown in Figure 2, the second power supply section 250A extends from the main section 320 to the second power supply point 252. That is, the second power supply section 250A extends linearly from the main section 320 to the second power supply point 252 in the first predetermined direction. The second power supply section 250A is located in the same position as the third section 336 in the front-rear direction. The second power supply section 250A is located on the first predetermined direction side of the third section 336.

[0048] As shown in Figure 2, the additional radiating element 270A extends directly from the feed point 210A toward the outside of the main antenna 30A. The additional radiating element 270A extends toward the outside of the feed point 210A. The additional radiating element 270A extends from the feed point 210A in a first predetermined direction. The additional radiating element 270A extends directly from the first feed point 220A toward the outside of the main antenna 30A. The additional radiating element 270A extends from the first feed point 220A in a first predetermined direction.

[0049] As shown in Figure 2, the additional radiating element 270A extends from the second segment 242A, which includes the first feed point 2421. This configuration ensures that the additional radiating element 270A extends from the vicinity of the first feed point 2421, making impedance matching easier.

[0050] As shown in Figure 2, the additional radiating element 270A has an additional linear portion 272A that extends linearly in a second predetermined direction. The additional linear portion 272A extends from the second segment 242A in a third predetermined direction. The linear portion 2422 and the additional linear portion 272A are located apart from each other in the lateral direction. The linear portion 2422 and the additional linear portion 272A are parallel to each other and constitute an open slot 260A with one end open. This makes impedance matching easier for the additional radiating element 270A. The open slot 260A has an opening at the end on the third predetermined direction side.

[0051] As shown in Figure 2, the additional radiating element 270A has a first extension portion 274. That is, unlike the additional radiating element 270 of the above-described embodiment, the additional radiating element 270A does not have a base portion 271. Here, the first extension portion 274 is the same as the first extension portion 274 of the double-resonant antenna 10 of the above-described embodiment, so a detailed explanation thereof is omitted.

[0052] In this modified embodiment, the additional radiating element 270A had an additional linear portion 272A and a first extended portion 274, but the present invention is not limited thereto. The additional radiating element 270A may consist only of a first extended portion 274 that extends directly from the second segment 242A, without having an additional linear portion 272A.

[0053] The length and shape of the additional radiating element 270A are determined so that it resonates electrically at the desired operating frequency. The desired operating frequency is different from the operating frequency of the main antenna 30A.

[0054] As can be seen from Figure 2, the modified double-resonant antenna 10A also has a structure that electrically resonates at two operating frequencies: the operating frequency of the main antenna (first resonant section) 30A and the operating frequency of the additional radiating element (second resonant section) 270A.

[0055] (Modification 2) As shown in Figure 3, the second modified example of the double-resonant antenna 10B comprises a main antenna 30B and an additional radiating element 270B. Note that this modified example of the double-resonant antenna 10B does not have a ground conductor around it.

[0056] As shown in Figure 3, the main antenna 30B and the additional radiating element 270B are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10B, the main antenna 30B and the additional radiating element 270B are integrally formed. The combination of the main antenna 30B and the additional radiating element 270B is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30B and the additional radiating element 270B may be composed of, for example, a metal member mounted on the substrate during use.

[0057] As shown in Figure 3, the main antenna 30B comprises a closed ring-shaped main section 320 and a feed section 210B. Here, the main section 320 is the same as the main section 320 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0058] As shown in Figure 3, the power supply unit 210B is provided so as to extend outward from the main unit 320. The power supply unit 210B is located on the first predetermined direction side (-X side) of the main unit 320. However, the present invention is not limited thereto, and the power supply unit 210B may be located on a side other than the -X side of the main unit 320. The power supply unit 210B has a first power supply section 220B, a second power supply section 250B, a first power supply point 2421B, and a second power supply point 252B.

[0059] As shown in Figure 3, the first feeding section 220B extends from the main section 320 to the first feeding point 2421B. The first feeding section 220B has a first section 230 and a second section 240B. Here, the first section 230 is the same as the first section 230 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0060] As shown in Figure 3, the second portion 240B extends from the first portion 230 in a second predetermined direction intersecting the first predetermined direction. That is, the second portion 240B extends from the first portion 230 in a second predetermined direction perpendicular to the first predetermined direction. The second portion 240B extends from the end of the first portion 230 in the first predetermined direction in the second predetermined direction. The second portion 240B has a linear portion 2422B that extends linearly in the second predetermined direction. More specifically, the second portion 240B is composed only of a linear portion 2422B that extends linearly in the second predetermined direction. Note that the length of the second portion 240B in this modified example is slightly shorter in the second predetermined direction compared to the second portion 240 in the above-described embodiment. In the second predetermined direction, the first power supply point 2421B is provided at the end of the second portion 240B.

[0061] As shown in Figure 3, the second portion 240B has a first segment 241 and a second segment 242B. Here, the first segment 241 is the same as the first segment 241 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation of it is omitted.

[0062] As shown in Figure 3, the second segment 242B extends from the first segment 241. That is, the second segment 242B extends linearly from the first segment 241 in a second predetermined direction. In the second predetermined direction, the center 245B of the second portion 240B is located between the first segment 241 and the second segment 242B. That is, in the second predetermined direction, the center 245B of the second portion 240B is located at the boundary between the first segment 241 and the second segment 242B. In the second predetermined direction, the first power supply point 2421B is provided at the end of the second segment 242B.

[0063] As shown in Figure 3, the second power supply section 250B extends from the main section 320 to the second power supply point 252B. More specifically, the second power supply section 250B extends linearly from the main section 320 in a first predetermined direction, then bends and extends in a third predetermined direction to the second power supply point 252B. The second power supply section 250B is located on the first predetermined direction side of the third section 336.

[0064] As shown in Figure 3, the excitation source 40 is connected to the first power supply point 2421B. Specifically, the core wire (not shown) of a coaxial cable (not shown) is connected to the first power supply point 2421B.

[0065] As shown in Figure 3, the excitation source 40 is connected to the second feed point 252B. Specifically, the outer conductor (not shown) of the coaxial cable is connected to the second feed point 252B.

[0066] As shown in Figure 3, the additional radiating element 270B extends directly from the feed point 210B toward the outside of the main antenna 30B. The additional radiating element 270B extends toward the outside of the feed point 210B. The additional radiating element 270B extends from the feed point 210B in a first predetermined direction. The additional radiating element 270B extends directly from the first feed point 220B toward the outside of the main antenna 30B. The additional radiating element 270B extends from the first feed point 220B in a first predetermined direction.

[0067] As shown in Figure 3, the additional radiating element 270B extends from the second segment 242B, which includes the first feed point 2421B. This configuration ensures that the additional radiating element 270B extends from the vicinity of the first feed point 2421B, making impedance matching easier.

[0068] As shown in Figure 3, the additional radiating element 270B has an additional linear portion 272B that extends linearly in a second predetermined direction. The linear portion 2422B and the additional linear portion 272B are located apart from each other in the lateral direction. The linear portion 2422B and the additional linear portion 272B are parallel to each other and constitute an open slot 260B with one end open. This makes impedance matching easier for the additional radiating element 270B. The open slot 260B has an opening at the end on the third predetermined direction side.

[0069] As shown in Figure 3, the additional radiating element 270B has a base portion 271B and a first extension portion 274. Here, the first extension portion 274 is the same as the first extension portion 274 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation of it will be omitted. The base portion 271B extends from the second segment 242B in a first predetermined direction. That is, the base portion 271B extends linearly from the second segment 242B in a first predetermined direction. The base portion 271B and the first extension portion 274 are connected by an additional linear portion 272B. The additional linear portion 272B extends from the base portion 271B in a third predetermined direction.

[0070] In this modified example, the additional radiating element 270B had a base portion 271B, an additional linear portion 272B, and a first extension portion 274, but the present invention is not limited thereto. The additional radiating element 270B may consist only of a first extension portion 274 extending directly from the second segment 242B, without having a base portion 271B and an additional linear portion 272B.

[0071] The length and shape of the additional radiating element 270B are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequency of the main antenna 30B.

[0072] As can be seen from Figure 3, the modified double-resonant antenna 10B also has a structure that electrically resonates at two operating frequencies: the operating frequency of the main antenna (first resonant section) 30B and the operating frequency of the additional radiating element (second resonant section) 270B.

[0073] (Variation 3) As shown in Figure 4, the third modified example of the double-resonant antenna 10C comprises a main antenna 30, an additional radiating element 270, and an auxiliary radiating element 280. Here, the main antenna 30 and the additional radiating element 270 are the same as the main antenna 30 and additional radiating element 270 of the double-resonant antenna 10 of the above-described embodiment, so a detailed explanation thereof is omitted. Note that the double-resonant antenna 10C of this modified example does not have a ground conductor provided around it.

[0074] As shown in Figure 4, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280 are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10C, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280 are integrally formed. The combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280 is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280 may, for example, be composed of a metal member mounted on the substrate during use.

[0075] As shown in Figure 4, the auxiliary radiating element 280 extends from the second feeding point 250 toward the outside of the main antenna 30. More specifically, the auxiliary radiating element 280 extends linearly from the second feeding point 250 toward the outside of the main antenna 30, then bends and extends in a third predetermined direction. The auxiliary radiating element 280 extends from the second feeding point 250 toward a first predetermined direction. The auxiliary radiating element 280 has an extended portion (first linear portion) 282 and a second linear portion 284.

[0076] As shown in Figure 4, the first linear section 282 extends from the second power supply section 250 in a first predetermined direction. The first linear section 282 extends linearly from the second power supply section 250 in a first predetermined direction. The first linear section 282 is located on the second predetermined direction side of the additional radiating element 270. That is, the additional radiating element 270 is located on the third predetermined direction side of the first linear section 282.

[0077] As shown in Figure 4, the second linear section 284 extends linearly from the first linear section 282 in a third predetermined direction. The second linear section 284 is located on the side of the additional radiating element 270 in the first predetermined direction. Note that the second linear section 284 is not connected to the additional radiating element 270.

[0078] The length and shape of the auxiliary radiating element 280 are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequencies of the main antenna 30 and the additional radiating element 270.

[0079] As can be seen from Figure 4, the auxiliary radiating element 280 operates as a third resonant section distinct from the first and second resonant sections. The first, second, and third resonant sections have different resonant frequencies from each other. Thus, the double-resonant antenna 10C of this modified example has a structure that electrically resonates at three operating frequencies: the operating frequency of the main antenna (first resonant section) 30, the operating frequency of the additional radiating element (second resonant section) 270, and the operating frequency of the auxiliary radiating element 280 (third resonant section).

[0080] (Modification 4) As shown in Figure 5, the fourth modified example of the double-resonant antenna 10D comprises a main antenna 30, an additional radiating element 270, and an auxiliary radiating element 280D. Here, the main antenna 30 and the additional radiating element 270 are the same as the main antenna 30 and additional radiating element 270 of the double-resonant antenna 10 of the above-described embodiment, so a detailed explanation thereof is omitted. Note that the double-resonant antenna 10D of this modified example does not have a ground conductor provided around it.

[0081] As shown in Figure 5, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280D are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10D, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280D are integrally formed. The combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280D is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280D may, for example, be composed of a metal member mounted on the substrate during use.

[0082] As shown in Figure 5, the auxiliary radiating element 280D extends from the second feeding point 250 toward the outside of the main antenna 30. The auxiliary radiating element 280D has an extension (first linear section) 282, a stub 283, and a second linear section 284. Here, the first linear section 282 and the second linear section 284 are the same as the first linear section 282 and the second linear section 284 of the auxiliary radiating element 280 of the third modified example, the double-resonant antenna 10C, so a detailed explanation of them is omitted.

[0083] As shown in Figure 5, the stub 283 extends from the first linear section 282 toward the additional radiating element 270 in a third predetermined direction opposite to the second predetermined direction. The stub 283 is spaced apart from the additional linear section 272 in the first predetermined direction. The stub 283 is located on the second predetermined direction side of the additional radiating element 270. Note that the stub 283 is not connected to the additional radiating element 270.

[0084] The length and shape of the auxiliary radiating element 280D are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequencies of the main antenna 30 and the additional radiating element 270.

[0085] As can be seen from Figure 5, the auxiliary radiating element 280D operates as a third resonant, distinct from the first and second resonant sections. The first, second, and third resonant sections have different resonant frequencies. Thus, the double-resonant antenna 10D of this modified example has a structure that electrically resonates at three operating frequencies: the operating frequency of the main antenna (first resonant section) 30, the operating frequency of the additional radiating element (second resonant section) 270, and the operating frequency of the auxiliary radiating element 280D (third resonant section).

[0086] (Variation 5) As shown in Figure 6, the fifth modified example of the double-resonant antenna 10E comprises a main antenna 30, an additional radiating element 270, and an auxiliary radiating element 280E. Here, the main antenna 30 and the additional radiating element 270 are the same as the main antenna 30 and additional radiating element 270 of the double-resonant antenna 10 of the above-described embodiment, so a detailed explanation thereof is omitted. Note that the double-resonant antenna 10E of this modified example does not have a ground conductor provided around it.

[0087] As shown in Figure 6, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280E are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10E, the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280E are integrally formed. The combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280E is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30, the additional radiating element 270, and the auxiliary radiating element 280E may, for example, be composed of a metal member mounted on the substrate during use.

[0088] As shown in Figure 6, the auxiliary radiating element 280E extends from the second feeding point 250 toward the outside of the main antenna 30. The auxiliary radiating element 280E has an extension (first linear section) 282, a stub 283, a second linear section 284, a cranked section 286, and an additional stub 287. Here, the first linear section 282, the stub 283, and the second linear section 284 are the same as the first linear section 282, the stub 283, and the second linear section 284 of the auxiliary radiating element 280D of the fourth modified example of the double-resonant antenna 10D, so a detailed explanation thereof is omitted.

[0089] As shown in Figure 6, the crank portion 286 extends from the second straight portion 284 in a first predetermined direction. More specifically, the crank portion 286 extends linearly from the second straight portion 284 in the first predetermined direction, then bends, extends linearly in the second predetermined direction, and then bends again to extend linearly in the first predetermined direction.

[0090] As shown in Figure 6, the additional stub 287 extends from the crank portion 286 in a third predetermined direction.

[0091] The length and shape of the auxiliary radiating element 280E are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequencies of the main antenna 30 and the additional radiating element 270.

[0092] As can be seen from Figure 6, the auxiliary radiating element 280E operates as a third resonant, distinct from the first and second resonant sections. The first, second, and third resonant sections have different resonant frequencies. Thus, the double-resonant antenna 10E of this modified example has a structure that electrically resonates at three operating frequencies: the operating frequency of the main antenna (first resonant section) 30, the operating frequency of the additional radiating element (second resonant section) 270, and the operating frequency of the auxiliary radiating element 280E (third resonant section).

[0093] (Experimental variation 6) As shown in Figure 7, the sixth modified example of the double-resonant antenna 10F comprises a main antenna 30F and an additional radiating element 270F. Note that this modified example of the double-resonant antenna 10F does not have a ground conductor around it.

[0094] As shown in Figure 7, the main antenna 30F and the additional radiating element 270F are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10F, the main antenna 30F and the additional radiating element 270F are integrally formed. The combination of the main antenna 30F and the additional radiating element 270F is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30F and the additional radiating element 270F may be composed of, for example, a metal member mounted on the substrate during use.

[0095] As shown in Figure 7, the main antenna 30F comprises a closed ring-shaped main section 320 and a feed section 210F. Here, the main section 320 is the same as the main section 320 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0096] As shown in Figure 7, the power supply unit 210F is provided so as to extend outward from the main unit 320. The power supply unit 210F is located on the first predetermined direction side (-X side) of the main unit 320. However, the present invention is not limited thereto, and the power supply unit 210F may be located on a side other than the -X side of the main unit 320. The power supply unit 210F has a first power supply section 220F, a second power supply section 250F, a first power supply point 2421F, and a second power supply point 252F.

[0097] As shown in Figure 7, the first feeding section 220F extends from the main section 320 to the first feeding point 2421F. The first feeding section 220F has a first section 230 and a second section 240F. Here, the first section 230 is the same as the first section 230 of the double-resonant antenna 10 in the above-described embodiment, so a detailed explanation thereof is omitted.

[0098] As shown in Figure 7, the second portion 240F extends from the first portion 230 in a second predetermined direction intersecting the first predetermined direction. That is, the second portion 240F extends from the first portion 230 in a second predetermined direction perpendicular to the first predetermined direction. The second portion 240F extends from the end of the first portion 230 in the first predetermined direction in the second predetermined direction. The second portion 240F has a linear portion 2422F that extends linearly in the second predetermined direction. More specifically, the second portion 240F is composed only of a linear portion 2422F that extends linearly in the second predetermined direction. In the lateral direction, the size of the second portion 240F is larger than the size of the fourth portion 338. In the lateral direction, the size of the linear portion 2422F is larger than the size of the fourth portion 338.

[0099] As shown in Figure 7, the second portion 240F has a first segment 241F and a second segment 242F.

[0100] As shown in Figure 7, the first segment 241F extends from the first portion 230. That is, the first segment 241F extends linearly from the first portion 230 in a second predetermined direction. The first segment 241F extends linearly from the end of the first portion 230 in a first predetermined direction in a second predetermined direction.

[0101] As shown in Figure 7, the second segment 242F extends from the first segment 241F. That is, the second segment 242F extends linearly from the first segment 241F in a second predetermined direction. In the second predetermined direction, the center 245F of the second portion 240F is located between the first segment 241F and the second segment 242F. That is, in the second predetermined direction, the center 245F of the second portion 240F is located at the boundary between the first segment 241F and the second segment 242F.

[0102] As shown in Figure 7, the second power supply section 250F extends outward from the main section 320. The second power supply section 250F extends from the main section 320 to the second power supply point 252F. That is, the second power supply section 250F extends linearly from the main section 320 to the second power supply point 252F in a first predetermined direction. The second power supply section 250F is located in the same position as the third section 336 in the front-rear direction. The second power supply section 250F is located on the first predetermined direction side of the third section 336.

[0103] As shown in Figure 7, the first power supply point 2421F is located in the first power supply section 220F. In the second predetermined direction, the first power supply point 2421F is located at the end of the second section 240F. More specifically, the first power supply point 2421F is located at the end of the second section 240F on both the first predetermined direction side (-X side) and the second predetermined direction side (-Y side). In the second predetermined direction, the first power supply point 2421F is located at the end of the second segment 242F. More specifically, the first power supply point 2421F is located at the end of the second segment 242F on both the first predetermined direction side (-X side) and the second predetermined direction side (-Y side). An excitation source 40 is connected to the first power supply point 2421F. Specifically, the core wire (not shown) of a coaxial cable (not shown) is connected to the first power supply point 2421F.

[0104] As shown in Figure 7, the second power supply point 252F is located at the second power supply section 250F. The excitation source 40 is connected to the second power supply point 252F. Specifically, the outer conductor (not shown) of the coaxial cable is connected to the second power supply point 252F.

[0105] As shown in Figure 7, the additional radiating element 270F extends directly from the feed point 210F toward the outside of the main antenna 30F. The additional radiating element 270F extends toward the outside of the feed point 210F. The additional radiating element 270F extends from the feed point 210F in a first predetermined direction. The additional radiating element 270F extends directly from the first feed point 220F toward the outside of the main antenna 30F. The additional radiating element 270F extends from the first feed point 220F in a first predetermined direction. The additional radiating element 270F extends from the second part 240F in a first predetermined direction. The additional radiating element 270F extends from the first segment 241F in a first predetermined direction.

[0106] As shown in Figure 7, the additional radiating element 270F of this modified example differs from the additional radiating elements 270, 270A, and 270B described above in that it does not have a base portion 271, 271B and additional linear portions 272, 272A, and 272B, and is composed only of a first extension portion 274F. As a result, the double-resonant antenna 10F of this modified example differs from the double-resonant antennas 10, 10A, 10B, 10C, 10D, and 10E described above in that it does not have open slots 260, 260A, and 260B. On the other hand, as described above, in the lateral direction, the size of the second portion 240F of the double-resonant antenna 10F of this modified example is larger than the size of the fourth portion 338. As a result, the double-resonant antenna 10F of this modified example can obtain good antenna characteristics despite not having open slots 260, 260A, and 260B. The first extension 274F extends from the first segment 241F in a first predetermined direction.

[0107] The length and shape of the additional radiating element 270F are determined so that it resonates electrically at the desired operating frequency. The desired operating frequency is different from the operating frequency of the main antenna 30F.

[0108] As can be seen from Figure 7, the modified double-resonant antenna 10F also has a structure that electrically resonates at two operating frequencies: the operating frequency of the main antenna (first resonant section) 30F and the operating frequency of the additional radiating element (second resonant section) 270F.

[0109] (Example 7) As shown in Figure 8, the seventh modified example of the double-resonant antenna 10G comprises a main antenna 30F, an additional radiating element 270F, and an auxiliary radiating element 280G. Here, the main antenna 30F and the additional radiating element 270F are the same as those of the double-resonant antenna 10F of the sixth modified example, so a detailed explanation of them is omitted. Note that the double-resonant antenna 10G of this modified example does not have a ground conductor around it.

[0110] As shown in Figure 8, the main antenna 30F, the additional radiating element 270F, and the auxiliary radiating element 280G are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10G, the main antenna 30F, the additional radiating element 270F, and the auxiliary radiating element 280G are integrally formed. The combination of the main antenna 30F, the additional radiating element 270F, and the auxiliary radiating element 280G is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30F, the additional radiating element 270F, and the auxiliary radiating element 280G may, for example, be composed of a metal member mounted on the substrate during use.

[0111] As shown in Figure 8, the auxiliary radiating element 280G extends from the second feeding point 250F toward the outside of the main antenna 30F. The auxiliary radiating element 280G has an extension (first linear section) 282G, a stub 283G, and a second linear section 284G.

[0112] As shown in Figure 8, the first linear section 282G extends from the second power supply section 250F in a first predetermined direction. The first linear section 282G extends linearly from the second power supply section 250F in a first predetermined direction. The first linear section 282G is located on the second predetermined direction side of the additional radiating element 270F. That is, the additional radiating element 270F is located on the third predetermined direction side of the first linear section 282G.

[0113] As shown in Figure 8, the stub 283G extends from the first linear portion 282G toward the additional radiating element 270F in a third predetermined direction opposite to the second predetermined direction. The stub 283G is spaced apart from the second portion 240F in the first predetermined direction. The stub 283G is located on the second predetermined direction side of the additional radiating element 270F. Note that the stub 283G is not connected to the additional radiating element 270F.

[0114] As shown in Figure 8, the second linear section 284G extends linearly from the first linear section 282G in a third predetermined direction. The second linear section 284G is located on the first predetermined direction side of the additional radiating element 270F. Note that the second linear section 284G is not connected to the additional radiating element 270F.

[0115] The length and shape of the auxiliary radiating element 280G are determined so that it resonates electrically at a desired operating frequency. The desired operating frequency is different from the operating frequencies of the main antenna 30F and the additional radiating element 270F.

[0116] As can be seen from Figure 8, the auxiliary radiating element 280G operates as a third resonant, distinct from the first and second resonant sections. The first, second, and third resonant sections have different resonant frequencies. Thus, the double-resonant antenna 10G of this modified example has a structure that electrically resonates at three operating frequencies: the operating frequency of the main antenna (first resonant section) 30F, the operating frequency of the additional radiating element (second resonant section) 270F, and the operating frequency of the auxiliary radiating element 280G (third resonant section).

[0117] (Variation 8) As shown in Figure 9, the eighth modified example of the double-resonant antenna 10H comprises a main antenna 30H, an additional radiating element 270F, and an auxiliary radiating element 280H. Here, the additional radiating element 270F is the same as the additional radiating element 270F of the sixth modified example of the double-resonant antenna 10F, so a detailed explanation of it is omitted. Note that the double-resonant antenna 10H of this modified example does not have a ground conductor around it.

[0118] As shown in Figure 9, the main antenna 30H, the additional radiating element 270F, and the auxiliary radiating element 280H are located on the same plane perpendicular to the vertical direction. In the double-resonant antenna 10H, the main antenna 30H, the additional radiating element 270F, and the auxiliary radiating element 280H are integrally formed. The combination of the main antenna 30H, the additional radiating element 270F, and the auxiliary radiating element 280H is composed of a conductive pattern formed on a substrate (not shown). However, the present invention is not limited thereto, and the combination of the main antenna 30H, the additional radiating element 270F, and the auxiliary radiating element 280H may, for example, be composed of a metal member mounted on the substrate during use.

[0119] As shown in Figure 9, the main antenna 30H comprises a closed ring-shaped main section 320 and a feed section 210H. Here, the main section 320 is the same as the main section 320 in the embodiment described above, so a detailed explanation thereof is omitted.

[0120] As shown in Figure 9, the power supply unit 210H is provided so as to extend outward from the main unit 320. The power supply unit 210H is located on the first predetermined direction side (-X side) of the main unit 320. However, the present invention is not limited thereto, and the power supply unit 210H may be located on a side other than the -X side of the main unit 320. The power supply unit 210H has a first power supply section 220F, a second power supply section 250H, a first power supply point 2421F, and a second power supply point 252H. Here, the first power supply section 220F and the first power supply point 2421F are the same as the first power supply section 220F and the first power supply point 2421F in the sixth modified example, so a detailed explanation thereof is omitted.

[0121] As shown in Figure 9, the second power supply section 250H extends outward from the main section 320. The second power supply section 250H is located on the first predetermined direction side of the third section 336. The second power supply section 250H has a third section 253 and a fourth section 254. The third section 253 extends from the main section 320 in the first predetermined direction. The third section 253 is located in the same position as the third section 336 in the front-rear direction. The third section 253 is located on the first predetermined direction side of the third section 336. The fourth section 254 extends from the third section 253 toward the additional radiating element 270F in the third predetermined direction opposite to the second predetermined direction. The fourth section 254 is spaced apart from the second section 240F in the first predetermined direction. A part of the fourth section 254 functions as a stub.

[0122] As shown in Figure 9, the second power supply point 252H is located in the second power supply section 250H. Specifically, the second power supply point 252H is located in the fourth section 254. The excitation source 40 is connected to the second power supply point 252H. Specifically, the outer conductor (not shown) of the coaxial cable is connected to the second power supply point 252H.

[0123] As shown in Figure 9, the auxiliary radiating element 280H extends from the second feeding point 250H toward the outside of the main antenna 30H. The auxiliary radiating element 280H extends from the second feeding point 250H in a first predetermined direction. More specifically, the auxiliary radiating element 280H extends linearly from the second feeding point 250H in the first predetermined direction, then bends and extends in a third predetermined direction. The auxiliary radiating element 280H has a first linear section 282H and a second linear section 284H.

[0124] As shown in Figure 9, the first linear section 282H extends from the second power supply section 250H in a first predetermined direction. The first linear section 282H extends linearly from the second power supply section 250H in a first predetermined direction. The first linear section 282H is located on the second predetermined direction side of the additional radiating element 270F. That is, the additional radiating element 270F is located on the third predetermined direction side of the first linear section 282H.

[0125] As shown in Figure 9, the second linear section 284H extends linearly from the first linear section 282H in a third predetermined direction. The second linear section 284H is located on the side of the additional radiating element 270F in the first predetermined direction. Note that the second linear section 284H is not connected to the additional radiating element 270F.

[0126] The length and shape of the auxiliary radiating element 280H are determined so that it resonates electrically at the desired operating frequency. The desired operating frequency is different from the operating frequencies of the main antenna 30H and the additional radiating element 270F.

[0127] As can be seen from Figure 9, the auxiliary radiating element 280H operates as a third resonant, distinct from the first and second resonant sections. The first, second, and third resonant sections have different resonant frequencies. Thus, the double-resonant antenna 10H of this modified example has a structure that electrically resonates at three operating frequencies: the operating frequency of the main antenna (first resonant section) 30H, the operating frequency of the additional radiating element (second resonant section) 270F, and the operating frequency of the auxiliary radiating element 280H (third resonant section).

[0128] Although the present invention has been described in detail with reference to embodiments above, the present invention is not limited thereto, and various modifications are possible.

[0129] In the above-described embodiments and modified examples, the double-resonant antennas 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H did not have a ground conductor around them. However, the present invention is not limited to this, and a ground conductor may be provided on the +X side or the second predetermined direction side (-Y side) of the main antennas 30, 30A, 30B, 30F, and 30H, and on the second predetermined direction side (-Y side) of the auxiliary radiating elements 280, 280D, 280E, 280G, and 280H.

[0130] The modified double-resonant antennas 10C, 10D, 10E, 10G, and 10H described above were equipped with auxiliary radiating elements 280, 280D, 280E, 280G, and 280H, but the present invention is not limited thereto, and may not be equipped with auxiliary radiating elements 280, 280D, 280E, 280G, and 280H. [Explanation of Symbols]

[0131] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H Double Resonant Antenna 30, 30A, 30B, 30F, 30H Main antenna 40 Excitation source 210, 210A, 210B, 210F, 210H Power supply section 220, 220A, 220B, 220F First power supply section 230 Part 1 240,240A,240B,240F 2nd part 241,241F First Segment 242, 242A, 242B, 242F Second Segment 2421, 2421B, 2421F First power supply point 2422,2422B,2422F Straight section 244 Extension 245,245A,245B,245F Center 250, 250A, 250B, 250F, 250H Second power supply section 252, 252B, 252F, 252H Second power supply point 253 Part 3 254 Part 4 260, 260A, 260B Open Slots 270, 270A, 270B, 270F Additional Radiation Element 271,271B base 272, 272A, 272B Additional straight section 274,274F 1st extension section 280, 280D, 280E, 280G, 280H Auxiliary radiating elements 282,282G,282H Extension section (first straight section) 283,283G stub 284,284G,284H 2nd straight section 286 Crank section 287 Additional stub 320 Main section 330 Part 1 334 Part 2 336 Part 3 338 Part 4

Claims

1. A double-resonant antenna comprising a main antenna and an additional radiating element, The main antenna comprises a closed ring-shaped main section and a power supply section. The power supply unit has a first power supply section, a second power supply section, a first power supply point, and a second power supply point. The first power supply section and the second power supply section each extend outward from the main section, The first power supply point is provided in the first power supply area, The second power supply point is provided in the second power supply area, The additional radiating element extends directly from the first feeding point toward the outside of the main antenna. A double-resonant antenna.

2. A double-resonant antenna according to claim 1, The first power supply portion has a first portion extending from the main portion in a first predetermined direction, and a second portion extending from the first portion in a second predetermined direction intersecting the first predetermined direction. The second portion has a first segment extending from the first portion and a second segment extending from the first segment. In the second predetermined direction, the center of the second portion is located between the first segment and the second segment. In the second predetermined direction, the first power supply point is provided at the end of the second segment, The second power supply section extends from the main section to the second power supply point. The additional radiating element extends from the second segment. A double-resonant antenna.

3. A double-resonant antenna according to claim 2, The second portion has a linear section that extends linearly in the second predetermined direction, The additional radiating element has an additional linear portion that extends linearly in the second predetermined direction, The aforementioned straight section and the aforementioned additional straight section are parallel to each other and constitute an open slot with one end open. A double-resonant antenna.

4. A double-resonant antenna according to claim 1, The first power supply portion has a first portion extending from the main portion in a first predetermined direction, and a second portion extending from the first portion in a second predetermined direction intersecting the first predetermined direction. The second portion has a first segment extending from the first portion and a second segment extending from the first segment. In the second predetermined direction, the center of the second portion is located between the first segment and the second segment. In the second predetermined direction, the first power supply point is provided at the end of the second segment, The second power supply section extends from the main section to the second power supply point. The additional radiating element extends from the first segment. A double-resonant antenna.

5. A double-resonant antenna according to claim 4, The double-resonant antenna further includes an extension extending from the second feeding point in the first predetermined direction, and a stub extending from the extension toward the additional radiating element in a third predetermined direction opposite to the second predetermined direction. The stub is positioned spaced apart from the second portion in the first predetermined direction. A double-resonant antenna.

6. A double-resonant antenna according to claim 4, The second power supply portion has a third portion extending from the main portion in a first predetermined direction, and a fourth portion extending from the third portion toward the additional radiating element in a third predetermined direction opposite to the second predetermined direction. The fourth portion is spaced apart from the second portion in the first predetermined direction. A double-resonant antenna.

7. A double-resonant antenna according to claim 1, The double-resonant antenna further comprises an auxiliary radiating element extending outward from the second feeding point toward the main antenna. A double-resonant antenna.

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