JP6145785B1

JP6145785B1 - Antenna device

Info

Publication number: JP6145785B1
Application number: JP2017011279A
Authority: JP
Inventors: 研志堀端; 小柳　芳雄; 芳雄小柳
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2017-01-25
Filing date: 2017-01-25
Publication date: 2017-06-14
Anticipated expiration: 2037-01-25
Also published as: JP2018121202A

Abstract

【課題】高いアンテナ利得と良好な軸比を確保しつつ、薄型化及び小型化が図れるアンテナ装置を提供する。【解決手段】誘電体層４の一方の面にループ導体２１と４つの放射素子２２とを含む第１の導体層２を有し、誘電体層４の他方の面に第２の導体層３を有する２層基板のみで構成する。また、ループ導体２１は、略１波長の電気長を持つ円弧状の形状を成し、放射素子２２は、ループ導体２１の外側に所定の間隔を空けて４つ配置され、それぞれがループ導体２１の円弧中心部から外側方向に略１／４波長の電気長を持ち、放射素子２２同士は、ループ導体２１の円弧中心部に対して回転対称となる。【選択図】図１Provided is an antenna device that can be reduced in thickness and size while ensuring a high antenna gain and a good axial ratio. A dielectric layer 4 has a first conductor layer 2 including a loop conductor 21 and four radiating elements 22 on one surface, and the second conductor layer 3 is disposed on the other surface of the dielectric layer 4. Only a two-layer substrate having The loop conductor 21 has an arc shape having an electrical length of approximately one wavelength, and four radiating elements 22 are arranged outside the loop conductor 21 at a predetermined interval, each of which is a loop conductor 21. The radiating elements 22 are rotationally symmetric with respect to the arc central portion of the loop conductor 21. [Selection] Figure 1

Description

本発明は、円偏波を放射するアンテナ装置に関する。 The present invention relates to an antenna device that radiates circularly polarized waves.

円偏波を放射するアンテナ装置は、受信端末向きの回転変動に強いことから、ＲＦＩＤ（ＲａｄｉｏＦｒｅｑｕｅｎｃｙＩｄｅｎｔｉｆｉｅｒ）システム（使用周波数９２０ＭＨｚ）や、ｉビーコン（登録商標）に代表されるＢｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙ（使用周波数２．４ＧＨｚ〜２．４８５ＧＨｚ）を用いたシステム等で用いられている。 Since an antenna device that radiates circularly polarized waves is resistant to rotational fluctuations toward the receiving terminal, an RFID (Radio Frequency Identifier) system (frequency used: 920 MHz) and Bluetooth (registered trademark) represented by i-Beacon (registered trademark) It is used in a system using Low Energy (operating frequency 2.4 GHz to 2.485 GHz).

例えば、ＲＦＩＤシステムにおいては、受信タグの位置による許容度を高めるために、リーダライタには円偏波が用いられ、受信タグには直線偏波が用いられている。
また、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙを使用したシステムにおいては、スマートフォン等の直線偏波を用いた受信端末で安定した受信を行うために、円偏波のビーコンが用いられることがある。 For example, in an RFID system, circular polarization is used for the reader / writer and linear polarization is used for the reception tag in order to increase the tolerance depending on the position of the reception tag.
Further, in a system using Bluetooth (registered trademark) Low Energy, a circularly polarized beacon may be used in order to perform stable reception by a receiving terminal using linearly polarized waves such as a smartphone.

円偏波を放射するアンテナ装置として、例えば特許文献１〜３に記載されたものがある。特許文献１に記載されたアンテナ装置は、ループ導体の上にボウタイ形状のスロットを配置した構成を採っている。特許文献２に記載されたアンテナ装置は、ループ導体の外周（同一平面）に閉ループを配置した構成を採っている。特許文献３に記載されたアンテナ装置は、ループ導体の上に２つ以上のスロットを配置した構成を採っている。 As an antenna device that radiates circularly polarized waves, for example, there are those described in Patent Documents 1 to 3. The antenna device described in Patent Document 1 has a configuration in which a bow-tie-shaped slot is arranged on a loop conductor. The antenna device described in Patent Document 2 has a configuration in which a closed loop is arranged on the outer periphery (same plane) of the loop conductor. The antenna device described in Patent Document 3 has a configuration in which two or more slots are arranged on a loop conductor.

特許第５３２３４４８号公報Japanese Patent No. 5323448 特許第４９３０９４７号公報Japanese Patent No. 4930947 特許第４７００８７３号公報Japanese Patent No. 4700703

円偏波の発生は、パッチアンテナ素子の一部を切り欠く等の簡易な構成で実現できる一方、広帯域に亘って良好な軸比と高いアンテナ利得を得るためには、アンテナをアレー状に多数設けたり、放射素子をアンテナの放射方向に対して厚みを持たせて立体的に配置したりする必要があり、小型化や薄型化が難しいという課題がある。 The generation of circularly polarized waves can be realized with a simple configuration such as cutting out a part of the patch antenna element. On the other hand, in order to obtain a good axial ratio and high antenna gain over a wide band, many antennas are arranged in an array. There is a problem in that it is difficult to reduce the size and thickness of the antenna, and it is necessary to provide the radiation element in a three-dimensional manner with a thickness in the radiation direction of the antenna.

例えば、特許文献１に記載のアンテナ装置にあっては、厚み方向に素子を配置する構成が必要であり、また高いアンテナ利得を得るには厚みが必要である。
また、特許文献２に記載のアンテナ装置にあっては、実施形態において１．５ＧＨｚでのアンテナの厚みを６．４ｍｍにしており、高いアンテナ利得を得るには厚みが必要である。
また、特許文献３に記載のアンテナ装置にあっては、厚み方向に素子を配置する構成が必要である。
このように、特許文献１〜特許文献３のいずれに記載のアンテナ装置にあっても、小型化や薄型化を図ることは難しい。 For example, the antenna device described in Patent Document 1 requires a configuration in which elements are arranged in the thickness direction, and thickness is necessary to obtain a high antenna gain.
In the antenna device described in Patent Document 2, the thickness of the antenna at 1.5 GHz is set to 6.4 mm in the embodiment, and the thickness is necessary to obtain a high antenna gain.
Further, the antenna device described in Patent Document 3 requires a configuration in which elements are arranged in the thickness direction.
As described above, it is difficult to reduce the size and thickness of the antenna device described in any of Patent Documents 1 to 3.

一方、薄型化が図れるアンテナ装置として、例えば図１６の斜視図に示すものがある。同図に示すアンテナ装置１００は、パッチアンテナ素子１０２の一部を切り欠くことで円偏波を放射できるようにしたものである。パッチアンテナ素子１０２は、正方形板状の誘電体１０１の表面中央部に設けられており、２つの対向する角部の一方（図に示す角部１０２ａ，１０２ｂ）が切り欠かれている。なお、誘電体１０１は、一辺が８０ｍｍ、厚みが１．６ｍｍで、裏面には全体に亘って導体が設けられている。パッチアンテナ素子１０２には給電部１０３が設けられており、この給電部１０３に例えば同軸ケーブル（図示略）が接続され、この同軸ケーブルを介して給電が行われる。 On the other hand, as an antenna device that can be reduced in thickness, for example, there is one shown in a perspective view of FIG. The antenna device 100 shown in the figure is configured to radiate circularly polarized waves by cutting out a part of the patch antenna element 102. The patch antenna element 102 is provided at the center of the surface of the square plate-like dielectric 101, and one of two opposing corner portions (corner portions 102a and 102b shown in the figure) is cut away. The dielectric 101 has a side of 80 mm and a thickness of 1.6 mm, and a conductor is provided on the entire back surface. The patch antenna element 102 is provided with a power supply unit 103. A coaxial cable (not shown) is connected to the power supply unit 103, for example, and power is supplied through the coaxial cable.

図１７は、図１６に示すアンテナ装置１００の軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。アンテナ装置１００は、２層基板で実現可能であるので、薄型化が可能である反面、帯域△ｆにおける軸比３ｄＢ以下の比帯域が狭く、良好な軸比が得られない。一方、アンテナ利得については、右旋円偏波ＣＷの方が左旋円偏波ＣＣＷよりも高く、右旋円偏波のアンテナとなっている。 FIG. 17 is a diagram showing the axial ratio (dB) and antenna gain (dBi) of the antenna device 100 shown in FIG. 16, where (a) is the axial ratio and (b) is the antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. Since the antenna device 100 can be realized with a two-layer substrate, the antenna device 100 can be reduced in thickness, but the ratio band of the axis ratio 3 dB or less in the band Δf is narrow, and a favorable axis ratio cannot be obtained. On the other hand, regarding the antenna gain, the right-handed circularly polarized wave CW is higher than the left-handed circularly polarized wave CCW, and is a right-handed circularly polarized antenna.

本発明は、高いアンテナ利得と良好な軸比を確保しつつ、薄型化及び小型化が図れるアンテナ装置を提供することを目的とする。 It is an object of the present invention to provide an antenna device that can be thinned and miniaturized while ensuring a high antenna gain and a good axial ratio.

本発明のアンテナ装置は、円偏波を放射する平板状のアンテナ装置であって、ループ導体と、導体からなる放射素子とを含む第１の導体層と、略全面が導体からなる第２の導体層と、前記第１の導体層と前記第２の導体層に挟まれた誘電体層と、を備え、前記ループ導体は、略１波長の電気長を持つ円弧状の形状であって、一端に給電部を有し、他端に所定のインピーダンスで終端される終端部を有し、前記放射素子は、前記ループ導体の外側に所定の間隔を空けて２つ以上配置され、前記ループ導体の円弧中心部から外側方向に略１／４波長の電気長を持つことで直線偏波で動作し、前記放射素子同士は、前記ループ導体の円弧中心部に対して回転対称である。 The antenna device of the present invention is a flat antenna device that radiates circularly polarized waves, and includes a first conductor layer that includes a loop conductor and a radiating element made of a conductor, and a second conductor that is substantially entirely made of a conductor. A conductor layer, and a dielectric layer sandwiched between the first conductor layer and the second conductor layer, wherein the loop conductor has an arc shape having an electrical length of approximately one wavelength, One end has a power feeding portion, the other end has a termination portion terminated with a predetermined impedance, and two or more of the radiating elements are arranged outside the loop conductor at a predetermined interval, and the loop conductor The radiating elements are rotationally symmetric with respect to the arc central portion of the loop conductor.

上記構成によれば、誘電体層の一方の面にループ導体と放射素子とを含む第１の導体層と、誘電体層の他方の面に第２の導体層とを有する２層基板で実現できるので、薄型化及び小型化が図れる。また、ループ導体は、略１波長の電気長を持ち、放射素子は、２つ以上配置され、それぞれが略１／４波長の電気長を持つので、高いアンテナ利得と良好な軸比を確保することができる。このように、高いアンテナ利得と良好な軸比を確保できるとともに、薄型化及び小型化が図れる。 According to the above configuration, a two-layer substrate having a first conductor layer including a loop conductor and a radiating element on one surface of the dielectric layer and a second conductor layer on the other surface of the dielectric layer is realized. As a result, the thickness and size can be reduced. Further, the loop conductor has an electrical length of approximately one wavelength, and two or more radiating elements are disposed, each having an electrical length of approximately ¼ wavelength, thus ensuring a high antenna gain and a good axial ratio. be able to. Thus, a high antenna gain and a good axial ratio can be ensured, and a reduction in thickness and size can be achieved.

本発明のアンテナ装置の一態様として例えば、前記放射素子は、第１の放射素子であり、前記第１の導体層は、導体からなる第２の放射素子を更に含み、前記第２の放射素子は、前記ループ導体の内側に所定の間隔を空けて配置されている。 As one aspect of the antenna device of the present invention, for example, the radiating element is a first radiating element, and the first conductor layer further includes a second radiating element made of a conductor, and the second radiating element is provided. Are arranged at a predetermined interval inside the loop conductor.

上記構成によれば、新たに設けた第２の放射素子により放射素子自体の面積が広くなり、より高いアンテナ利得が得られる。 According to the above configuration, the area of the radiating element itself is increased by the newly provided second radiating element, and a higher antenna gain can be obtained.

本発明のアンテナ装置の一態様として例えば、前記第２の導体層は、前記ループ導体の円弧中心部に対応する中心部において導体が設けられていない。 As one aspect of the antenna device of the present invention, for example, the second conductor layer is not provided with a conductor at the center corresponding to the arc center of the loop conductor.

上記構成によれば、第２の導体層の導体が設けられていない部分に無線回路を設けることができ、無線回路を内蔵したアンテナ装置を提供することができる。 According to the above configuration, the wireless circuit can be provided in a portion where the conductor of the second conductor layer is not provided, and an antenna device incorporating the wireless circuit can be provided.

本発明のアンテナ装置の一態様として例えば、前記放射素子は、略扇状の平面形状を有している。 As one aspect of the antenna device of the present invention, for example, the radiating element has a substantially fan-like planar shape.

上記構成によれば、放射素子の形状を略扇状の平面形状としても、高いアンテナ利得と良好な軸比を確保できるとともに、薄型化及び小型化が図れる。 According to the above configuration, even if the shape of the radiating element is a substantially fan-like planar shape, a high antenna gain and a good axial ratio can be ensured, and a reduction in thickness and size can be achieved.

本発明のアンテナ装置の一態様として例えば、前記放射素子は、略矩形状の平面形状を有している。 As one aspect of the antenna device of the present invention, for example, the radiating element has a substantially rectangular planar shape.

上記構成によれば、放射素子の形状を略矩形状の平面形状としても、高いアンテナ利得と良好な軸比を確保できるとともに、薄型化及び小型化が図れる。 According to the above configuration, even if the shape of the radiating element is a substantially rectangular planar shape, a high antenna gain and a good axial ratio can be ensured, and a reduction in thickness and size can be achieved.

本発明のアンテナ装置は、高いアンテナ利得と良好な軸比を確保しつつ、薄型化及び小型化が図れる。 The antenna device of the present invention can be reduced in thickness and size while ensuring a high antenna gain and a good axial ratio.

本発明の第１実施形態に係るアンテナ装置の概略構成を示す平面図及び断面図The top view and sectional drawing which show schematic structure of the antenna device which concerns on 1st Embodiment of this invention. 図１のアンテナ装置をＢｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙを用いたシステム等で用いるときの寸法を示す図The figure which shows the dimension when using the antenna apparatus of FIG. 1 with the system etc. which used Bluetooth (trademark) Low Energy. 図１のアンテナ装置のアンテナ表面における磁界分布を示す図The figure which shows magnetic field distribution in the antenna surface of the antenna apparatus of FIG. 図１のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the antenna apparatus of FIG. 本発明の第２実施形態に係るアンテナ装置の概略構成を示す平面図The top view which shows schematic structure of the antenna device which concerns on 2nd Embodiment of this invention. 図５中の第２の放射素子の拡大図Enlarged view of the second radiating element in FIG. 図５のアンテナ装置をＢｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙを用いたシステム等で用いるときの中央部における寸法を示す図The figure which shows the dimension in the center part when using the antenna apparatus of FIG. 5 with the system etc. which used Bluetooth (trademark) Low Energy. 図５のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the antenna apparatus of FIG. 本発明の第３実施形態に係るアンテナ装置の概略構成を示す平面図及び断面図The top view and sectional drawing which show schematic structure of the antenna device which concerns on 3rd Embodiment of this invention. 図１のアンテナ装置の第１変形例の概略構成を示す平面図The top view which shows schematic structure of the 1st modification of the antenna apparatus of FIG. 図１０の第１変形例のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the antenna apparatus of the 1st modification of FIG. 図１のアンテナ装置の第２変形例の概略構成を示す平面図The top view which shows schematic structure of the 2nd modification of the antenna apparatus of FIG. 図１２の第２変形例のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the antenna apparatus of the 2nd modification of FIG. 図１のアンテナ装置の第３変形例の概略構成を示す平面図The top view which shows schematic structure of the 3rd modification of the antenna apparatus of FIG. 図１４の第３変形例のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the antenna apparatus of the 3rd modification of FIG. 従来のアンテナ装置の概略構成を示す斜視図A perspective view showing a schematic configuration of a conventional antenna device 図１６の従来のアンテナ装置の軸比とアンテナ利得を示す図The figure which shows the axial ratio and antenna gain of the conventional antenna apparatus of FIG.

以下、本発明を実施するための好適な実施の形態について、図面を参照して詳細に説明する。 DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

（第１実施形態）
図１は、本発明の第１実施形態に係るアンテナ装置１Ａの概略構成を示す平面図及び断面図である。この場合、同図の（ａ）が表面側の平面図、（ｂ）が裏面側の平面図、（ｃ）がＡ−Ａ線断面図である。 (First embodiment)
FIG. 1 is a plan view and a cross-sectional view showing a schematic configuration of an antenna apparatus 1A according to the first embodiment of the present invention. In this case, (a) in the figure is a plan view on the front side, (b) is a plan view on the back side, and (c) is a cross-sectional view along the line AA.

本実施形態に係るアンテナ装置１Ａは、円偏波を放射する平板状のアンテナ装置であり、ループ導体２１と、導体からなる放射素子２２とを含む第１の導体層２と、略全面が導体からなる第２の導体層３と、第１の導体層２と第２の導体層３に挟まれた誘電体層４と、を備える。ループ導体２１は、略１波長の電気長を持つ円弧状の形状であって、一端に給電部２１１（図１の（ｃ）参照）を有し、他端に所定のインピーダンスで終端される終端部２１２（図１の（ｃ）参照）を有する。 An antenna device 1A according to the present embodiment is a flat antenna device that radiates circularly polarized waves, and includes a first conductor layer 2 including a loop conductor 21 and a radiating element 22 made of a conductor, and a substantially entire surface being a conductor. And a dielectric layer 4 sandwiched between the first conductor layer 2 and the second conductor layer 3. The loop conductor 21 has an arc shape having an electrical length of approximately one wavelength, has a power feeding portion 211 (see FIG. 1C) at one end, and is terminated at a predetermined impedance at the other end. Part 212 (see FIG. 1C).

給電部２１１は、ループ導体２１の一端の直下にあけられた誘電体層４の貫通孔に挿入され、一端がループ導体２１の一端に接続される導線２１１ａと、導線２１１ａの他端に接続される端子２１１ｂとから構成される。給電部２１１には、例えば同軸ケーブル（図示略）を介して給電が行われる。終端部２１２は、ループ導体２１の他端の直下にあけられた誘電体層４の貫通孔に挿入され、一端がループ導体２１の他端に接続される導線２１２ａと、導線２１２ａの他端と第２の導体層３との間に介挿される所定のインピーダンス素子（例えば、５０Ωの抵抗素子）２１２ｂとから構成される。 The power feeding unit 211 is inserted into a through hole of the dielectric layer 4 formed immediately below one end of the loop conductor 21, and one end is connected to one end of the loop conductor 21 and the other end of the conducting wire 211a. Terminal 211b. Power is supplied to the power supply unit 211 via, for example, a coaxial cable (not shown). The end portion 212 is inserted into a through-hole in the dielectric layer 4 that is opened directly below the other end of the loop conductor 21, and has one end connected to the other end of the loop conductor 21, and the other end of the conductor 212 a. A predetermined impedance element (for example, a resistance element of 50Ω) 212b interposed between the second conductor layer 3 and the second conductor layer 3 is formed.

放射素子２２は、略扇状の平面形状を有し、ループ導体２１の外側に所定の間隔を空けて４つ配置される。各放射素子２２は、ループ導体２１の円弧中心部から外側方向に略１／４波長の電気長を持ち、直線偏波で動作する。放射素子２２同士は、ループ導体２１の円弧中心部に対して回転対称となっている。ループ導体２１と４つの放射素子２２を成す導体や第２の導体層３を成す導体の材質は、例えば銅である。また、誘電体層４の材質は、例えばガラスエポキシ（ＮＥＭＡ規格：ＦＲ−４）である。なお、ＮＥＭＡは、ＮａｔｉｏｎａｌＥｌｅｃｔｒｉｃａｌＭａｎｕｆａｃｔｕｒｅｒｓＡｓｓｏｃｉａｔｉｏｎの略である。 The radiating element 22 has a substantially fan-like planar shape, and four radiating elements 22 are arranged outside the loop conductor 21 with a predetermined interval. Each radiating element 22 has an electrical length of approximately ¼ wavelength outward from the center of the arc of the loop conductor 21 and operates with linearly polarized waves. The radiating elements 22 are rotationally symmetric with respect to the center of the arc of the loop conductor 21. The material of the conductor forming the loop conductor 21 and the four radiating elements 22 and the conductor forming the second conductor layer 3 is, for example, copper. The material of the dielectric layer 4 is, for example, glass epoxy (NEMA standard: FR-4). NEMA is an abbreviation for National Electrical Manufacturers Association.

図２は、本実施形態に係るアンテナ装置１ＡをＢｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙ（使用周波数２．４ＧＨｚ〜２．４８５ＧＨｚ）を用いたシステム等で用いるときの寸法を示す図である。同図の（ａ）はアンテナ装置１Ａの全体を示し、（ｂ）はアンテナ装置１Ａの中央部分を示す。同図の（ａ），（ｂ）に示すように、アンテナ装置１Ａの全体の直径が８０ｍｍ、対向する放射素子２２の一方から他方までの距離が５３．９ｍｍ、各放射素子２２の幅が１６ｍｍ、各放射素子２２の円弧が７５度、ループ導体２１と放射素子２２の線間が０．５ｍｍ、ループ導体２１の開口端の間隔が２．７ｍｍ、放射素子２２間の隙間が１５度、アンテナ装置１Ａの全体の厚さが１．６ｍｍ（図示略）となる。なお、アンテナ装置１Ａの全体の直径は、ＦＢ比（ＦｒｏｎｔｔｏＢａｃｋＲａｔｉｏ）に関係する。また、ループ導体２１は、上述したように１周が略１波長で動作する。また、放射素子２２は、上述したように略１／４波長で動作する。また、ループ導体２１と放射素子２２の線間を変えることで、放射素子２２へ分配する電力量が変化する。 FIG. 2 is a diagram showing dimensions when the antenna device 1A according to the present embodiment is used in a system or the like using Bluetooth (registered trademark) Low Energy (operating frequency 2.4 GHz to 2.485 GHz). (A) of the figure shows the whole antenna device 1A, and (b) shows the central portion of the antenna device 1A. As shown in FIGS. 5A and 5B, the overall diameter of the antenna device 1A is 80 mm, the distance from one of the opposing radiating elements 22 to the other is 53.9 mm, and the width of each radiating element 22 is 16 mm. The arc of each radiating element 22 is 75 degrees, the line between the loop conductor 21 and the radiating element 22 is 0.5 mm, the distance between the open ends of the loop conductor 21 is 2.7 mm, and the gap between the radiating elements 22 is 15 degrees. The total thickness of the apparatus 1A is 1.6 mm (not shown). The overall diameter of the antenna device 1A is related to the FB ratio (Front to Back Ratio). Further, as described above, the loop conductor 21 operates with substantially one wavelength for one turn. Further, the radiating element 22 operates at approximately a quarter wavelength as described above. Further, by changing the line between the loop conductor 21 and the radiating element 22, the amount of power distributed to the radiating element 22 changes.

図３は、本実施形態に係るアンテナ装置１Ａのアンテナ表面における磁界分布を示す図である。同図において、４つの放射素子２２のうち、給電部２１１に最も近い位置にある放射素子２２−１の位相を０度と表示し、他の放射素子２２−２〜２２−４の位相を時計回りに９０度、１８０度、２７０度と表示している。また、図中点線で示す矢印３０は、磁界成分を示している。ループ導体２１は、１周３６０度となる電気長で動作する。ループ導体２１の外周に位置する放射素子２２−１は、図中符号３１で示すようにループ導体２１と容量結合する。ループ導体２１上の磁界成分は、連続して外周に位置する他の放射素子２２−２〜２２−４にも発生する。なお、ループ導体２１は、マイクロストリップラインとして動作する。 FIG. 3 is a diagram showing a magnetic field distribution on the antenna surface of the antenna device 1A according to the present embodiment. In the figure, among the four radiating elements 22, the phase of the radiating element 22-1 closest to the power feeding unit 211 is displayed as 0 degree, and the phases of the other radiating elements 22-2 to 22-4 are clocked. Around 90, 180 and 270 degrees are displayed. An arrow 30 indicated by a dotted line in the figure indicates a magnetic field component. The loop conductor 21 operates with an electrical length of 360 degrees per round. The radiating element 22-1 located on the outer periphery of the loop conductor 21 is capacitively coupled to the loop conductor 21 as indicated by reference numeral 31 in the figure. The magnetic field component on the loop conductor 21 is also generated in the other radiating elements 22-2 to 22-4 that are continuously located on the outer periphery. The loop conductor 21 operates as a microstrip line.

ループ導体２１の外周に配置された放射素子２２−１〜２２−４が時計回り（図中矢印３２で示す方向）に順番に励振することで電磁波が放射される。このとき放射される電磁波は左旋円偏波となる。なお、電磁波の放射方向はアンテナ装置１Ａの裏面側から見るのが基本であるので、左旋円偏波となる。給電部２１１と終端部２１２を逆にすれば、放射素子２２−１〜２２−４が反時計回り（図中矢印３２で示す方向と逆方向）に順番に励振するので、右旋円偏波となる。 Electromagnetic waves are radiated when the radiating elements 22-1 to 22-4 arranged on the outer periphery of the loop conductor 21 are sequentially excited clockwise (in the direction indicated by the arrow 32 in the figure). The electromagnetic waves radiated at this time are left-handed circularly polarized waves. In addition, since the radiation direction of electromagnetic waves is basically viewed from the back side of the antenna device 1A, it becomes a left-handed circularly polarized wave. If the power feeding section 211 and the terminal section 212 are reversed, the radiating elements 22-1 to 22-4 are excited in the counterclockwise order (in the direction opposite to the direction indicated by the arrow 32 in the figure), so that the right-handed circularly polarized wave It becomes.

図４は、本実施形態に係るアンテナ装置１Ａの軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。同図から分かるように、本実施形態に係るアンテナ装置１Ａは、△ｆ帯で高いアンテナ利得と良好な軸比が得られる。図１７で示した従来のアンテナ装置１００の軸比と比較すると、本実施形態に係るアンテナ装置１Ａは、軸比３ｄＢ以下の比帯域が広くなっている。また、従来のアンテナ装置１００のアンテナ利得と比較すると、左旋円偏波ＣＣＷでのアンテナ利得と右旋円偏波ＣＷでのアンテナ利得との差が大きくなっている。この差が大きくなるほど良く、軸比の値が下がる。従来のアンテナ装置１００では、軸比３ｄＢから略１ｄＢ下がっているのに対し、本実施形態に係るアンテナ装置１Ａでは、軸比３ｄＢから略２ｄＢ下がっている。明らかに、本実施形態に係るアンテナ装置１Ａの方が良好な軸比が得られているのが分かる。 FIG. 4 is a diagram showing an axial ratio (dB) and an antenna gain (dBi) of the antenna device 1A according to the present embodiment, where (a) in FIG. 4 is an axial ratio and (b) is an antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. As can be seen from the figure, the antenna device 1A according to the present embodiment can obtain a high antenna gain and a good axial ratio in the Δf band. Compared with the axial ratio of the conventional antenna device 100 shown in FIG. 17, the antenna device 1A according to the present embodiment has a wider bandwidth than the axial ratio of 3 dB. Further, compared with the antenna gain of the conventional antenna device 100, the difference between the antenna gain in the left-handed circularly polarized wave CCW and the antenna gain in the right-handed circularly polarized wave CW is larger. The larger this difference, the better and the lower the axial ratio value. In the conventional antenna device 100, the axial ratio is about 1 dB lower than 3 dB, whereas in the antenna device 1A according to the present embodiment, the axial ratio is about 2 dB lower than 3 dB. Obviously, the antenna device 1A according to the present embodiment has a better axial ratio.

また、本実施形態に係るアンテナ装置１Ａは、誘電体層４の一方の面にループ導体２１と４つの放射素子２２とを含む第１の導体層２を有し、誘電体層４の他方の面に第２の導体層３を有する厚み１．６ｍｍの２層基板のみで構成できるので、薄型化及び小型化が図れる。なお、基板の両面に導体パターンがあるものが両面基板もしくは２層基板と呼ばれる。 The antenna device 1 </ b> A according to the present embodiment has the first conductor layer 2 including the loop conductor 21 and the four radiating elements 22 on one surface of the dielectric layer 4, and the other of the dielectric layers 4. Since it can be constituted by only a two-layer substrate having a thickness of 1.6 mm having the second conductor layer 3 on the surface, it is possible to reduce the thickness and size. A substrate having a conductor pattern on both sides is called a double-sided substrate or a two-layer substrate.

このように、本実施形態に係るアンテナ装置１Ａによれば、誘電体層４の一方の面にループ導体２１と４つの放射素子２２とを含む第１の導体層２を有し、誘電体層４の他方の面に第２の導体層３を有する２層基板のみで構成されるので、薄型化及び小型化が図れる。また、ループ導体２１は、略１波長の電気長を持つ円弧状の形状を成し、放射素子２２は、ループ導体の外側に所定の間隔を空けて４つ配置され、それぞれがループ導体２１の円弧中心部から外側方向に略１／４波長の電気長を持ち、放射素子２２同士は、ループ導体２１の円弧中心部に対して回転対称となるので、高いアンテナ利得と良好な軸比を確保することができる。 As described above, the antenna device 1A according to the present embodiment has the first conductor layer 2 including the loop conductor 21 and the four radiating elements 22 on one surface of the dielectric layer 4, and the dielectric layer. Since it is composed of only a two-layer substrate having the second conductor layer 3 on the other surface of 4, the thickness and size can be reduced. In addition, the loop conductor 21 has an arc shape having an electrical length of approximately one wavelength, and four radiating elements 22 are arranged outside the loop conductor at a predetermined interval. Since the electrical length is approximately ¼ wavelength outward from the center of the arc and the radiating elements 22 are rotationally symmetric with respect to the center of the arc of the loop conductor 21, a high antenna gain and a good axial ratio are ensured. can do.

（第２実施形態）
図５は、本発明の第２実施形態に係るアンテナ装置１Ｂの概略構成を示す平面図である。この場合、同図の（ａ）が表面側の平面図、（ｂ）が裏面側の平面図である。なお、Ａ−Ａ線断面図は、前述した図１の（ｃ）に示す第１実施形態に係るアンテナ装置１ＡのＡ−Ａ線断面図と同一であるので、省略する。また、図５において、前述した第１実施形態に係るアンテナ装置１Ａと共通する部材には同一の符号を付けている。 (Second Embodiment)
FIG. 5 is a plan view showing a schematic configuration of an antenna apparatus 1B according to the second embodiment of the present invention. In this case, (a) in the figure is a plan view on the front side, and (b) is a plan view on the back side. The AA line sectional view is the same as the AA line sectional view of the antenna device 1A according to the first embodiment shown in FIG. In FIG. 5, members that are the same as those in the antenna device 1 </ b> A according to the first embodiment described above are denoted by the same reference numerals.

図５に示すように、本実施形態に係るアンテナ装置１Ｂは、第１実施形態に係るアンテナ装置１Ａと同一の構成を有する以外に、導体からなる第２の放射素子２３を有している。第２の放射素子２３は、第１の導体層２に含まれ、ループ導体２１の内側に所定の間隔を空けて配置される。図６は、図５中の第２の放射素子２３の拡大図である。同図において、第２の放射素子２３は、十字形状部分２３−１と、この十字形状部分２３−１の４つの先端のそれぞれと一体であって、ループ導体２１の内側に沿う円弧形状の小片部分２３−２とから構成される。隣り合う小片部分２３−２の間隔は、ループ導体２１の開口端の間隔と略同一である。なお、第２の放射素子２３は、放射素子２２とともに第１の導体層２に含まれるので、第２の放射素子２３に対して放射素子２２を第１の放射素子２２と呼ぶ。 As shown in FIG. 5, the antenna device 1B according to the present embodiment has a second radiating element 23 made of a conductor, in addition to having the same configuration as the antenna device 1A according to the first embodiment. The second radiating element 23 is included in the first conductor layer 2 and is arranged inside the loop conductor 21 with a predetermined interval. FIG. 6 is an enlarged view of the second radiating element 23 in FIG. In the same figure, the second radiating element 23 is integrated with the cross-shaped portion 23-1 and each of the four tips of the cross-shaped portion 23-1, and is an arc-shaped piece along the inside of the loop conductor 21. It is comprised from the part 23-2. The interval between the adjacent small piece portions 23-2 is substantially the same as the interval between the open ends of the loop conductor 21. Since the second radiating element 23 is included in the first conductor layer 2 together with the radiating element 22, the radiating element 22 is referred to as the first radiating element 22 with respect to the second radiating element 23.

図７は、本実施形態に係るアンテナ装置１ＢをＢｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙを用いたシステム等で用いるときの中央部における寸法を示す図である。なお、アンテナ装置１Ｂの中央部以外の部分の寸法は、第１実施形態に係るアンテナ装置１Ａと同一である。同図に示すように、第２の放射素子２３の直径が１７．４ｍｍ、全長が３１．４ｍｍ、線幅が１ｍｍ、第２の放射素子２３の小片部分２３−２の円弧が７５度、ループ導体２１との線間が０．５ｍｍである。第２の放射素子２３の全長を３１．４ｍｍとすることで、略１／２波長で動作する。また、ループ導体２１との線間を変えることで、第２の放射素子２３に分配される電力が変化する。 FIG. 7 is a diagram illustrating dimensions at the center when the antenna device 1B according to the present embodiment is used in a system using Bluetooth (registered trademark) Low Energy. The dimensions of the antenna device 1B other than the central portion are the same as those of the antenna device 1A according to the first embodiment. As shown in the figure, the diameter of the second radiating element 23 is 17.4 mm, the total length is 31.4 mm, the line width is 1 mm, the arc of the small piece portion 23-2 of the second radiating element 23 is 75 degrees, the loop The distance between the conductor 21 and the conductor 21 is 0.5 mm. By setting the total length of the second radiating element 23 to 31.4 mm, the second radiating element 23 operates at approximately ½ wavelength. Moreover, the electric power distributed to the 2nd radiation | emission element 23 changes by changing the space | interval with the loop conductor 21. FIG.

図８は、本実施形態に係るアンテナ装置１Ｂの軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。同図から分かるように、本実施形態に係るアンテナ装置１Ｂは、△ｆ帯で高いアンテナ利得と良好な軸比が得られる。特に、アンテナ利得は、２．４ＧＨｚ帯で、第１実施形態に係るアンテナ装置１Ａよりも２ｄＢｉ程上がっている。また、左旋円偏波ＣＣＷでのアンテナ利得と右旋円偏波ＣＷでのアンテナ利得との差も第１実施形態に係るアンテナ装置１Ａと同様に大きくなっている。 FIG. 8 is a diagram illustrating the axial ratio (dB) and the antenna gain (dBi) of the antenna device 1B according to the present embodiment, where (a) in FIG. 8 is the axial ratio and (b) is the antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. As can be seen from the figure, the antenna device 1B according to the present embodiment can obtain a high antenna gain and a good axial ratio in the Δf band. In particular, the antenna gain is about 2.4 dB higher in the 2.4 GHz band than the antenna device 1A according to the first embodiment. Further, the difference between the antenna gain in the left-handed circularly polarized wave CCW and the antenna gain in the right-handed circularly polarized wave CW is also large as in the antenna device 1A according to the first embodiment.

このように、第１の放射素子２２に加えて、第２の放射素子２３を設けたことで、放射素子自体の面積が広くなり、第１実施形態に係るアンテナ装置１Ａと比べて２．４ＧＨｚ帯でより高いアンテナ利得が得られる。また、厚み１．６ｍｍの２層基板で実現可能であるので、薄型化及び小型化が図れる。 Thus, by providing the second radiating element 23 in addition to the first radiating element 22, the area of the radiating element itself is increased, and 2.4 GHz compared to the antenna device 1A according to the first embodiment. A higher antenna gain is obtained in the band. Further, since it can be realized by a two-layer substrate having a thickness of 1.6 mm, the thickness and size can be reduced.

（第３実施形態）
図９は、本発明の第３実施形態に係るアンテナ装置１Ｃの概略構成を示す平面図及び断面図である。この場合、同図の（ａ）が表面側の平面図、（ｂ）が裏面側の平面図、（ｃ）がＡ−Ａ線断面図である。なお、同図において、第１実施形態に係るアンテナ装置１Ａと共通する部材には同一の符号を付けている。 (Third embodiment)
FIG. 9 is a plan view and a cross-sectional view showing a schematic configuration of an antenna apparatus 1C according to the third embodiment of the present invention. In this case, (a) in the figure is a plan view on the front side, (b) is a plan view on the back side, and (c) is a cross-sectional view along the line AA. In the figure, members common to the antenna device 1A according to the first embodiment are denoted by the same reference numerals.

図９に示すように、本実施形態に係るアンテナ装置１Ｃは、第１実施形態に係るアンテナ装置１Ａと同一の構成を有するが、無線回路２６を有している点と、アンテナ装置１Ｃの裏面側に設けられた第２の導体層３の中心部、即ちループ導体２１の円弧中心部に対応する中心部において導体が設けられていない点が異なっている。第２の導体層３の導体の無い部分を空白部２５と呼ぶこととし、この空白部２５に無線回路２６が配置される。 As shown in FIG. 9, the antenna device 1C according to the present embodiment has the same configuration as the antenna device 1A according to the first embodiment, but has a wireless circuit 26, and the back surface of the antenna device 1C. The difference is that no conductor is provided at the center of the second conductor layer 3 provided on the side, that is, at the center corresponding to the arc center of the loop conductor 21. A portion of the second conductor layer 3 having no conductor is referred to as a blank portion 25, and the wireless circuit 26 is disposed in the blank portion 25.

無線回路２６は、給電部２１１の導線２１１ａの他端即ち第２の導体層３側の端に接続される。給電部２１１の導線２１１ａの一端は、第１実施形態に係るアンテナ装置１Ａと同様にループ導体２１の一端に接続される。終端部２１２においても第１実施形態に係るアンテナ装置１Ａと同様に、導線２１２ａの一端がループ導体２１の他端に接続され、導線２１２ａの他端が所定のインピーダンス素子（例えば、５０Ωの抵抗素子）２１２ｂを介して第２の導体層３に接続される。無線回路２６は、例えば、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＩＣ（ＩｎｔｅｇｒａｔｅｄＣｉｒｃｕｉｔ）及び該ＩＣの動作に必要な周辺回路部品や信号配線の集合である。無線回路２６から給電部２１１に給電が行われる。 The radio circuit 26 is connected to the other end of the conducting wire 211 a of the power feeding unit 211, that is, the end on the second conductor layer 3 side. One end of the conducting wire 211a of the power feeding unit 211 is connected to one end of the loop conductor 21 as in the antenna device 1A according to the first embodiment. Similarly to the antenna device 1A according to the first embodiment, one end of the conducting wire 212a is connected to the other end of the loop conductor 21 and the other end of the conducting wire 212a is a predetermined impedance element (for example, a 50Ω resistance element). ) It is connected to the second conductor layer 3 through 212b. The wireless circuit 26 is, for example, a Bluetooth (registered trademark) IC (Integrated Circuit) and a set of peripheral circuit components and signal wirings necessary for the operation of the IC. Power is supplied from the wireless circuit 26 to the power supply unit 211.

このように、第２の導体層３の中心部に導体の無い空白部２５を設けたことで、その空白部２５に無線回路２６を設けることができ、無線回路２６を内蔵したアンテナ装置を提供することができる。 Thus, by providing the blank portion 25 without a conductor at the center of the second conductor layer 3, the radio circuit 26 can be provided in the blank portion 25, and an antenna device incorporating the radio circuit 26 is provided. can do.

なお、前述した第１〜第３実施形態に係るアンテナ装置１Ａ〜１Ｃは、４つの放射素子２２を有したが、放射素子２２の数に限定はなく２つ以上であればよい。また、放射素子２２の形状を略扇状の平面形状としたが、例えば略矩形の平面形状としてもよい。以下、第１実施形態に係るアンテナ装置１Ａの変形例について説明する。 Although the antenna devices 1A to 1C according to the first to third embodiments described above have the four radiating elements 22, the number of the radiating elements 22 is not limited and may be two or more. Moreover, although the shape of the radiation element 22 is a substantially fan-like planar shape, it may be a substantially rectangular planar shape, for example. Hereinafter, modified examples of the antenna device 1A according to the first embodiment will be described.

（第１実施形態の第１変形例）
図１０は、第１実施形態に係るアンテナ装置１Ａの第１変形例の概略構成を示す平面図である。同図に示すように、第１変形例のアンテナ装置１Ｄは、８つの放射素子２２を有する。各放射素子２２の形状は、第１実施形態に係るアンテナ装置１Ａのものと同一の略扇状の平面形状である。 (First modification of the first embodiment)
FIG. 10 is a plan view showing a schematic configuration of a first modification of the antenna device 1A according to the first embodiment. As shown in the figure, the antenna device 1D of the first modified example has eight radiating elements 22. The shape of each radiating element 22 is a substantially fan-like planar shape that is the same as that of the antenna device 1A according to the first embodiment.

図１１は、第１変形例のアンテナ装置１Ｄの軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。同図から分かるように、第１変形例のアンテナ装置１Ｄは、第１実施形態に係るアンテナ装置１Ａと比べて放射素子２２の数が多い分、第１実施形態に係るアンテナ装置１Ａよりさらに広い帯域で良好な軸比が得られる。また、アンテナ利得は、左旋円偏波ＣＣＷと右旋円偏波ＣＷ共に変動が小さく、第１実施形態に係るアンテナ装置１Ａより、より綺麗な円偏波が得られる。また、厚み１．６ｍｍの２層基板で実現可能であるので、薄型化及び小型化が図れる。 FIG. 11 is a diagram illustrating the axial ratio (dB) and the antenna gain (dBi) of the antenna device 1D of the first modified example, where (a) in FIG. 11 is the axial ratio and (b) is the antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. As can be seen from the figure, the antenna device 1D according to the first modification is wider than the antenna device 1A according to the first embodiment because the number of the radiating elements 22 is larger than that of the antenna device 1A according to the first embodiment. Good axial ratio can be obtained in the band. Further, the antenna gain varies little for both the left-handed circularly polarized wave CCW and the right-handed circularly polarized wave CW, and a more beautiful circularly polarized wave can be obtained from the antenna device 1A according to the first embodiment. Further, since it can be realized by a two-layer substrate having a thickness of 1.6 mm, the thickness and size can be reduced.

（第１実施形態の第２変形例）
図１２は、第１実施形態に係るアンテナ装置１Ａの第２変形例の概略構成を示す平面図である。同図に示すように、第２変形例のアンテナ装置１Ｅは、３つの放射素子２２を有する。各放射素子２２の形状は、第１実施形態に係るアンテナ装置１Ａのものと同一の略扇状の平面形状である。 (Second modification of the first embodiment)
FIG. 12 is a plan view showing a schematic configuration of a second modification of the antenna device 1A according to the first embodiment. As shown in the figure, the antenna device 1E of the second modification has three radiating elements 22. The shape of each radiating element 22 is a substantially fan-like planar shape that is the same as that of the antenna device 1A according to the first embodiment.

図１３は、第２変形例のアンテナ装置１Ｅの軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。同図から分かるように、第２変形例のアンテナ装置１Ｅは、△ｆ帯で良好な軸比とアンテナ利得が得られる。性能的には第１実施形態に係るアンテナ装置１Ａと殆ど変わらない。また、厚み１．６ｍｍの２層基板で実現可能であるので、薄型化及び小型化が図れる。 FIG. 13 is a diagram illustrating the axial ratio (dB) and the antenna gain (dBi) of the antenna device 1E of the second modified example, in which (a) is the axial ratio and (b) is the antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. As can be seen from the figure, the antenna device 1E of the second modification can obtain a good axial ratio and antenna gain in the Δf band. The performance is almost the same as the antenna device 1A according to the first embodiment. Further, since it can be realized by a two-layer substrate having a thickness of 1.6 mm, the thickness and size can be reduced.

（第１実施形態の第３変形例）
図１４は、第１実施形態に係るアンテナ装置１Ａの第３変形例の概略構成を示す平面図である。同図に示すように、第３変形例のアンテナ装置１Ｆは、５つの放射素子２２Ａを有する。各放射素子２２Ａの形状は、第１実施形態に係るアンテナ装置１Ａのものとは異なり、略矩形状の平面形状を成している。 (Third Modification of First Embodiment)
FIG. 14 is a plan view showing a schematic configuration of a third modification of the antenna device 1A according to the first embodiment. As shown in the figure, the antenna device 1F of the third modification has five radiating elements 22A. The shape of each radiation element 22A is different from that of the antenna device 1A according to the first embodiment, and has a substantially rectangular planar shape.

図１５は、第３変形例のアンテナ装置１Ｆの軸比（ｄＢ）とアンテナ利得（ｄＢｉ）を示す図であり、同図の（ａ）が軸比、（ｂ）がアンテナ利得である。同図の（ａ），（ｂ）に示す帯域△ｆ（２．４ＧＨｚ〜２．５ＧＨｚ）は、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙの帯域である。同図から分かるように、第３変形例のアンテナ装置１Ｆは、△ｆ帯で良好な軸比とアンテナ利得が得られる。性能的には第１実施形態に係るアンテナ装置１Ａと殆ど変わらない。また、厚み１．６ｍｍの２層基板で実現可能であるので、薄型化及び小型化が図れる。 FIG. 15 is a diagram illustrating the axial ratio (dB) and the antenna gain (dBi) of the antenna device 1F according to the third modified example, in which (a) is the axial ratio and (b) is the antenna gain. Bands Δf (2.4 GHz to 2.5 GHz) shown in (a) and (b) of the figure are Bluetooth (registered trademark) Low Energy bands. As can be seen from the figure, the antenna device 1F of the third modification can obtain a good axial ratio and antenna gain in the Δf band. The performance is almost the same as the antenna device 1A according to the first embodiment. Further, since it can be realized by a two-layer substrate having a thickness of 1.6 mm, the thickness and size can be reduced.

以上、第１実施形態に係るアンテナ装置１Ａの変形例について例を挙げて説明したが、
第１〜第３の変形例は、第２，第３実施形態に係るアンテナ装置１Ｂ，１Ｃにも適用できることは言うまでもない。 The modification example of the antenna device 1A according to the first embodiment has been described above by way of example.
Needless to say, the first to third modifications can also be applied to the antenna devices 1B and 1C according to the second and third embodiments.

以上、本発明の第１〜第３実施形態及び第１実施形態の第１〜第３変形例を詳細に説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは当業者にとって明らかである。 As described above, the first to third embodiments of the present invention and the first to third modifications of the first embodiment have been described in detail, but various changes and modifications are made without departing from the spirit and scope of the present invention. It will be apparent to those skilled in the art that this is possible.

本発明に係るアンテナ装置は、ＲＦＩＤシステムや、Ｂｌｕｅｔｏｏｔｈ（登録商標）ＬｏｗＥｎｅｒｇｙを用いたシステム等に適用可能である。 The antenna device according to the present invention can be applied to an RFID system, a system using Bluetooth (registered trademark) Low Energy, or the like.

１Ａ〜１Ｆアンテナ装置
２第１の導体層
３第２の導体層
４誘電体層
２１ループ導体
２２，２２−１〜２２−４，２２Ａ放射素子（第１の放射素子）
２３第２の放射素子
２５空白部
２６無線回路
２１１給電部
２１２終端部
２１２ｂインピーダンス素子 1A to 1F Antenna device 2 First conductor layer 3 Second conductor layer 4 Dielectric layer 21 Loop conductor 22, 22-1 to 22-4, 22A Radiating element (first radiating element)
23 Second radiating element 25 Blank part 26 Radio circuit 211 Feeding part 212 Terminating part 212b Impedance element

Claims

A flat antenna device that radiates circularly polarized waves,
A first conductor layer including a loop conductor and a radiating element made of a conductor;
A second conductor layer substantially entirely made of a conductor;
A dielectric layer sandwiched between the first conductor layer and the second conductor layer,
The loop conductor has an arc shape having an electrical length of approximately one wavelength, has a power feeding portion at one end, and has a termination portion terminated with a predetermined impedance at the other end,
Two or more radiating elements are arranged outside the loop conductor at a predetermined interval, and have an electrical length of about ¼ wavelength outward from the center of the arc of the loop conductor, thereby allowing linearly polarized light. Work,
The antenna device according to claim 1, wherein the radiating elements are rotationally symmetric with respect to a circular arc center portion of the loop conductor.

The antenna device according to claim 1,
The radiating element is a first radiating element;
The first conductor layer further includes a second radiating element made of a conductor,
The antenna device according to claim 1, wherein the second radiating elements are arranged at a predetermined interval inside the loop conductor.

The antenna device according to claim 1,
The antenna device, wherein the second conductor layer is not provided with a conductor in a central portion corresponding to a circular arc central portion of the loop conductor.

The antenna device according to any one of claims 1 to 3,
The antenna device, wherein the radiating element has a substantially fan-like planar shape.

The antenna device according to any one of claims 1 to 3,
The antenna device, wherein the radiating element has a substantially rectangular planar shape.