JP3586929B2 - Portable wireless device antenna and portable wireless device - Google Patents

Description

【００２６】
とすることにより、いわゆる半波長ダイポールアンテナ（以下、半波長アンテナという）の構成と同等となる。一般に、半波長アンテナでは、アンテナ軸に軸対象で、アンテナと垂直方向に等距離の面では無指向性の指向パターンを描く。また、半波長アンテナの入力インピーダンスは、次式で示される。
【００２７】
【数２】

【００２８】
但し、２Ｌ（＝２Ｌ１）：アンテナ全長、ρ：アンテナの線径（半径）、ｋ＝２π／λ、λ：波長、Ｗｅ：波動インピーダンスである。通常、全長２Ｌ＝λ／２の半波長アンテナの抵抗Ｒは、ほぼ長さの２乗に比例し、全長２Ｌが短くなるほど小さくなり、入力リアンクタンスＸは、長さの変化に対してほぼ直線的に変化し、全長２Ｌが短い場合には、線径ρが大きいほど大きくなる。一般に、実際のアンテナに適用するためには、入力インピーダンスは、純抵抗に近い方が便利であり、そのためには、上記数式２より、アンテナ全長２Ｌを半波長λ／２より少し短くする必要があることが分かる。すなわち、１つのアンテナ長Ｌ（＝Ｌ１）をλ／４の０．９〜０．９５程度短くすればよい。
【００２９】
また、半波長アンテナにおける放射電力Ｗｒは、次式で示すようになる。
【００３０】
【数３】

【００３１】
さらに、放射抵抗Ｒｒは、前述した入力インピーダンスＺより次式で示すようになる。
【００３２】
【数４】

【００３３】
また、指向性利得Ｇｄは、
【００３４】
【数５】

【００３５】
となることは周知である。
【００３６】
Ｂ．第２実施例
Ｂ−１．第２実施例の構成
次に、図３（ａ）は、本発明の第２実施例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。図において、バンド部２ａ，２ｂには、各々、その長手方向に延びる２本のアンテナ素子導線１２ａ，１２ｂ、１３ａ，１３ｂが間隔ｄを離して内蔵されており、コ字状の給電端子１４ａ，１４ｂで電気的に接続されている。本第２実施例によるバンド・アンテナの１つのアンテナ長Ｌ１は、給電素子１４ａ（１４ｂ）の長さとアンテナ素子導線１０ａ（１０ｂ）の長さを足したものとなる。このように、本第２実施例では、アンテナを複数の半波長アンテナ素子で構成している。
【００３７】
上述した構成において、同一の半波長アンテナを２本、間隔ｄだけ離して配列したアンテナの入力インピーダンスは、次式で示される。
【００３８】
【数６】

【００３９】
また、上記相互インピーダンスＺ１２（＝Ｒ１２＋ｊＸ１２）は次式で表される。
【００４０】
【数７】

【００４１】
このように、本第２実施例によるアンテナでは、上記相互インピーダンスＺ１２が入力インピーダンスに直列に付加される。ここで、リアクタンス分Ｘ１２を「０」とするには、すなわち純抵抗とするには、ｄ／（λ／４）＝０．５または２．８、ｄ＝λ／８または０．７λとすればよい。すなわち、アンテナ素子導線１２ａ，１２ｂとアンテナ素子導線１３ａ，１３ｂとの間隔ｄを１／８波長、または１波長の０．７程度にする必要がある。この場合、最大放射方向の利得Ｇｈは、前述した第１実施例による半波長アンテナに比べて、
【００４２】
【数８】

【００４３】
となるので、間隔ｄがλ／４の２．５〜３倍程度のとき、利得を４〜５ｄＢ上げることができる。
【００４４】
Ｃ．第２実施例の変形例
また、図４（ａ）は、上述した第２実施例の変形例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。図において、バンド部２ａ，２ｂには、各々、その長手方向に延びる略コ字状のアンテナ素子導線１５ａ，１５ｂが内蔵されており、給電端子１６ａ，１６ｂで電気的に接続されている。アンテナ素子導線１５ａ，１５ｂおよび給電端子１６ａ，１６ｂからなるアンテナにおいて、有効に動作するときの素子の長さは、それぞれ長さＬ１，Ｌ２（Ｌ１＜Ｌ２）と異なっており、その間は間隔ｄだけ離れている。このアンテナの特性は、上述した図３に示すものと同様であるので、説明を省略する。
【００４５】
Ｄ．第３実施例
次に、図５（ａ）は、本発明の第３実施例によるアンテナの略構成を示す概念図である。また、図５（ｂ）は、アンテナの等価回路を示す回路図であり、同図（ｃ）は、上記等価回路を模式的に示す概念図である。図において、バンド部２ａ，２ｂには、各々、その長手方向に延びる２本のアンテナ素子導線１７ａ，１８ａ、１７ｂ，１８ｂが間隔ｄを離して内蔵されており、それぞれが給電端子２０ａ〜２０ｄを介して給電部である無線回路部６に電気的に接続されている。また、上記アンテナ素子導線１８ａに接続された給電端子２０ｂと給電部６の間には、移相器２１が介挿されており、該移相器２１を用いて、同相の半波長アンテナの代わりに、位相の異なる半波長アンテナとして作用させている。
【００４６】
本第３実施例では、前述した図３，図４に示すアンテナにおいて、バンド部２ａ，２ｂの寸法（幅）の制約から間隔ｄが確保できない場合、図５（ｃ）に示すように、位相を余計にずらした波形をアンテナ素子導線１８ａ，１８ｂに印加することで、間隔ｄを短くしても、適当なアンテナ特性（例えば、間隔ｄを利得が大きい５λ／８〜３λ／４）を得ることができるので、第１および第２実施例と等価のアンテナを構成できる。
【００４７】
Ｅ．第４実施例
次に、図６（ａ）は、本発明の第４実施例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。図において、バンド部２ａ，２ｂには、各々、その長手方向に延びる２本のアンテナ素子導線２１ａ，２２ａ、２１ｂ，２２ｂが間隔ｄを離して内蔵されており、一対のアンテナ素子導線２１ａ，２１ｂのみが給電端子２３ａ，２３ｂを介して給電部である無線回路部６に電気的に接続されている。他のアンテナ素子導線２２ａ，２２ｂは、負荷ＺＬを介して直列接続され、給電されているアンテナ素子導線２１ａ，２１ｂの近傍に（間隔ｄで）配設されている。給電されているアンテナ素子導線２１ａ，２１ｂの近傍には、強い電磁界が生じるので、その近くにアンテナ素子導線２２ａ，２２ｂを配設すれば、直接給電しなくても、電流が流れ、アンテナ素子として作用する。すなわち、上記給電されないアンテナ素子導線２２ａ，２２ｂは、「反射器（ｒｅｆｌｅｃｔｏｒ）」、または「導波器（ｄｉｒｅｃｔｏｒ）」として作用する。
【００４８】
上述したアンテナ全体の入力インピーダンス、すなわちアンテナ素子導線２１ａ，２１ｂの端子から見た入力インピーダンスは、次式で示される。
【００４９】
【数９】

【００５０】
また、アンテナ素子導線２１ａ，２１ｂからなる半波長アンテナに対する利得Ｇｈ（θ，φ）は、次式で示される。
【００５１】
【数１０】

【００５２】
したがって、無給電のアンテナ素子導線２２ａ，２２ｂの間に介挿されている負荷ＺＬの値を変えることにより、半波長アンテナの入力インピーダンスや利得を変えることができる。φ＝０の方向で利得を上げるように負荷ＺＬを調節すれば、アンテナ素子導線２２ａ，２２ｂは「導波器」として作用し、また、φ＝８０の方向で利得を上げるように負荷ＺＬを調整すれば、素子導線２２ａ，２２ｂは、「反射器」として作用する。
【００５３】
Ｆ．第４実施例の変形例
次に、図７（ａ）は、上述した第４実施例の変形例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。本変形例では、図示するように、上記負荷ＺＬを「０」として無給電のアンテナ素子導線２２ａ，２２ｂを短絡し、いわゆる「八木・宇田アンテナ」の「反射器」を配設している。この場合には、よく知られているように、負荷ＺＬの代わりに、無給電のアンテナ素子導線２２ａ，２２ｂの長さを変えることで、負荷ＺＬを変えるのと同様に作用する。すなわち、無給電のアンテナ素子導線２２ａ，２２ｂの長さＬ２を、アンテナ素子導線２１ａ，２１ｂからなる半波長アンテナ（２Ｌ１＝λ／２，Ｌ１＝λ／４）に対して、長くしたり短くしたりして変えてみると、長さの変化に対して、全長が半波長に近い１本の導線の自己インピーダンスにおける抵抗分の変化は少ない一方、リアクタンス分の変化は大きい。また、相互インピーダンスＺ２１は、無給電のアンテナ素子導線２２ａ，２２ｂの長さＬ２の違いによって、あまり変化しないため、結局、長さＬ２を変えると、リアクタンスＸ２２だけが変わるのと同等となる。
【００５４】
すなわち、無給電のアンテナ素子導線２２ａ，２２ｂの長さＬ２がλ／４（すなわち、全長２Ｌ２がλ／２）の半波長アンテナに比べ、１倍以上では「反射器」として作用し、正面利得が６ｄＢほど低下し、一方、長さＬ２がλ／４（すなわち、全長２Ｌが半波長）に比べ、０．８〜０．９程度と短いときには、正面利得が２〜３ｄＢ上がり、「導波器」として作用する。また、アンテナ素子導線が太いほど、短い長さで導波器となる。
【００５５】
Ｆ．第４実施例の他の変形例
次に、図８（ａ）は、上述した第４実施例の他の変形例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。当該変形例では、図７に示す無給電のアンテナ素子導線２２ａ，２２ｂに代えて、図８に示すように、半波長アンテナを構成するアンテナ素子導線２１ａ，２１ｂの長さより、０．８〜０．９程度短い長さを有する、無給電のアンテナ素子導線２４ａ，２４ｂを間隔ｄ３だけ離して設けている。この無給電のアンテナ素子導線２４ａ，２４ｂは「導波器」として作用する。
【００５６】
Ｆ．第４実施例の他の変形例
また、図９（ａ）は、上述した第４実施例の他の変形例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。図において、バンド部２ｃ，２ｄは、前述したバンド部２ａ，２ｂに対して、幅広のバンドであり、２列の穴が設けられている。該バンド部２ｃ，２ｄには、それぞれ３本のアンテナ素子導線２５ａ，２６ａ，２７ａ、２５ｂ，２６ｂ，２７ｂが間隔ｄ３だけ離れて内蔵されており、そのうち１対のアンテナ素子導線２５ａ，２５ｂは、給電部である無線回路部６に接続され、前述した半波長アンテナを構成しており、他の２対のアンテナ素子導線２６ａ，２６ｂ、２７ａ，２７ｂは、無給電で、「導波器」を構成している。この場合、上記アンテナ素子導線２６ａ，２６ｂ、２７ａ，２７ｂが「導波器」として作用する際に、電波の送信（あるいは受信）の方向に逆の指向性を持たせるには、アンテナ素子導線２５ａ，２５ｂ（給電部も含む）とアンテナ素子導線２６ａ，２６ｂとの位置を入れ替えればよい。
【００５７】
Ｆ．第４実施例の他の変形例
次に、図１０（ａ）は、上述した第４実施例の他の変形例によるアンテナの略構成を示す概念図であり、同図（ｂ）は、アンテナの等価回路を示す回路図である。図において、バンド部２ｃ，２ｄには、それぞれ３本のアンテナ素子導線３０ａ，３１ａ，３２ａ、３０ｂ，３１ｂ，３２ｂが内蔵されており、そのうち略中央のアンテナ素子導線３１ａ，３１ｂは、給電部である無線回路部６に接続され、前述した長さＬ１の半波長アンテナを構成しており、アンテナ素子導線３０ａ，３０ｂは、アンテナ素子導線３１ａ，３１ｂの近傍に間隔ｄ２だけ離して配設され、アンテナ素子導線３２ａ，３２ｂは、アンテナ素子導線３１ａ，３１ｂの近傍に間隔ｄ３だけ離して配設されている。
【００５８】
また、アンテナ素子導線３０ａ，３０ｂによる有効長は、半波長アンテナの長さＬ１より長く、長さＬ２となっており、アンテナ素子導線３２ａ，３２ｂは、半波長アンテナの長さＬ１より短く、長さＬ３となっている。アンテナ素子導線３０ａ，３０ｂは、１本の反射器として作用し、アンテナ素子導線３２ａ，３２ｂは、１本の導波器として作用する。言い換えると、本変形例では、３素子の一般的な「八木・宇田アンテナ」をバンド・アンテナとして構成したものである。本変形例では、半波長アンテナに対して、アンテナ素子導線３２ａ，３２ｂの間隔ｄ３や長さＬ３を変えることにより、入力インピーダンスや利得を変えることができる。また、導波器の本数を増やすことで、利得を上げることができる。本変形例によれば、上記３素子（反射器＋導波器＋アンテナ）で、通常の半波長アンテナに比べ、利得を４〜６ｄＢ程度上げることができる。
【００５９】
【発明の効果】
本発明によれば、本体を利用者に装着するためのバンド部の長手方向に、可塑性を有する導電体で、長手方向に流れる電流の分布が中心点に対して対称になるように、中心点から給電される給電アンテナ素子導線を設け、ダイポールアンテナを構成するようにしたので、以下の効果が得られる。
（１）バー・アンテナを用いないので、超短波帯以上の高周波電波を使用する無線機器にも使用できる。
（２）また、イヤホン兼用のひも型アンテナのように、使用時に取り付けたり、巻き出したりする必要がなく、使い勝手が向上する。
（３）また、ループを構成しないので、バックル部の構造や製造が簡単になり、容易に製造できる。
（４）また、利用者の腕の太さ等に影響を受けないので、アンテナ長が変化せず、一定の長さにできるので、アンテナ特性や無線装置の感度や性能、安定性を向上できる。
（５）また、アンテナのパラメータを容易に調整できるので、使用状況に応じて、所望の受信感度や安定した受信や通信を行うことができる。
（６）また、バンドの寸法（幅）の制約から第１の給電アンテナ素子導線と、第２の給電アンテナ素子導線の間隔が確保できない場合でも、位相を余計にずらすことにより、適正なアンテナ特性を得ることができる。
【図面の簡単な説明】
【図１】本発明の第１実施例による携帯無線機器用アンテナを適用した腕時計型無線機器の構成を示す正面図および断面図である。
【図２】本第１実施例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図３】本発明の第２実施例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図４】本第２実施例の変形例によるアンテナの略構成を示す概念図およびアンテナの等価回路を示す回路図である。
【図５】本発明の第３実施例によるアンテナの略構成を示す概念図、等価回路および概念図である。
【図６】本発明の第４実施例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図７】本第４実施例の変形例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図８】本第４実施例の他の変形例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図９】本第４実施例の他の変形例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【図１０】本第４実施例の他の変形例によるアンテナの略構成を示す概念図および等価回路を示す回路図である。
【符号の説明】
１ 本体部
２ａ，２ｂ バンド部
３ バックル部
１ｂ 表示部
１ｃ，１ｃ スイッチ
４ 遊環
３ａ 突棒
５ 穴
６ 無線回路部
７ａ，７ｂ 給電端子
１０ａ，１０ｂ アンテナ素子導線（給電アンテナ素子導線）
１１ａ，１１ｂ 台座
１２ａ，１２ｂ アンテナ素子導線（給電アンテナ素子導線）
１３ａ，１３ｂ アンテナ素子導線（第２の給電アンテナ素子導線）
１４ａ，１４ｂ 給電端子
１５ａ，１５ｂ アンテナ素子導線（給電アンテナ素子導線、第２の給電アンテナ素子導線）
１６ａ，１６ｂ 給電端子
１７ａ，１７ｂ アンテナ素子導線（給電アンテナ素子導線）
１８ａ，１８ｂ アンテナ素子導線（第２の給電アンテナ素子導線）
２０ａ〜２０ｄ 給電端子
２１ 移相器（移相手段）
２１ａ，２１ｂ アンテナ素子導線（給電アンテナ素子導線）
２２ａ，２２ｂ アンテナ素子導線（無給電アンテナ素子導線、反射器）
２３ａ，２３ｂ 給電端子
ＺＬ 負荷
２４ａ，２４ｂ アンテナ素子導線（無給電アンテナ素子導線、導波器）
２ｃ，２ｄ バンド部
２５ａ，２５ｂ アンテナ素子導線（給電アンテナ素子導線）
２６ａ，，２６ｂ アンテナ素子導線（複数の無給電アンテナ素子導線、導波器）
２７ａ，２７ｂ アンテナ素子導線（複数の無給電アンテナ素子導線、導波器）
３０ａ，３０ｂ アンテナ素子導線（複数の無給電アンテナ素子導線、第２の無給電アンテナ素子導線）
３１ａ，３１ｂ アンテナ素子導線（給電アンテナ素子導線）
３２ａ，３２ｂ アンテナ素子導線（複数の無給電アンテナ素子導線、第１の無給電アンテナ素子導線）[0001]
[Industrial applications]
The present invention relates to a portable wireless device antenna and a portable wireless device for performing transmission and reception in a wristwatch-type wireless broadcast receiver, transceiver, mobile phone, wireless calling terminal, communication device, and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various types of ultra-small portable wireless devices, such as wristwatches, have been proposed because of their small size, light weight, and excellent convenience in portability. In this portable wireless device, since it is worn on the wrist like a wristwatch, the size and size of the wristwatch are limited. Therefore, it is particularly desirable to reduce the size of the antenna for receiving or transmitting radio waves. I was
[0003]
This is due to the rapid progress in miniaturization and low power of wireless circuits due to advances in integrated circuit technology, and the use of small, high-performance, high-capacity small batteries and rechargeable batteries as power sources. On the other hand, miniaturization of antennas has been restricted by the area that the radio wave can traverse, or the antenna antenna can be tuned by the length of the antenna, whose tuning detection performance is closely related to the wavelength of the radio wave. This is because it was difficult to realize because of the restrictions.
[0004]
Therefore, for example, in a wristwatch-type wireless device having a limited size, a bar antenna or the like is conventionally incorporated in a case for a radio wave of a medium frequency band (MF) such as an AM radio receiver, A VHF band FM radio, a wireless calling terminal (pager), and the like use a cord-type antenna that also serves as an earphone or a loop-type band antenna that uses a band portion of a wristwatch.
[0005]
[Problems to be solved by the invention]
However, the above-described conventional antenna for a portable wireless device uses a bar antenna, a string-type antenna, and a loop-type band antenna, and thus has the following problems.
(B) In recent years, in the case of a bar antenna or the like built in a case of a wristwatch type wireless device, the frequency has been increasing to several hundred MHz band and further to several GHz band. The desired performance cannot be obtained in the equipment. In addition, there is a problem that the use of a conductive material such as a metal as the material of the case has to be avoided in order to be built in the case portion.
[0006]
(B) In addition, in the case of a string-type antenna that also serves as an earphone such as an FM radio receiver, it must be attached or unwound when used, and there is a problem in usability and form.
(C) Further, in the case of a loop-type band antenna, the structure and manufacturing are complicated, for example, the loop is formed when the antenna is connected to the buckle portion of the arm band in order to form the loop. There was a problem that the cost of the department would be increased. In addition, in such a method, not only can it be used only when worn on the arm, but also the size of the loop antenna changes depending on the size of the arm and the antenna length changes, so in order to keep the antenna characteristics constant, It was necessary to provide a separate adjustment circuit to compensate for changes in antenna length.
[0007]
(D) In a wristwatch-type portable wireless device, even if a metal conductor is attached to a band portion to be worn on an arm, it is an object close to a conductor or a dielectric in an antenna loop even if the metal conductor is attached to the band. Since the arm of the human body enters, the characteristics become unstable, and there has been a problem that desired reception sensitivity and stable reception and communication cannot be performed.
(E) In addition, since the ratio of the radiation resistance to the input resistance of the loop antenna is generally small, and it is necessary to cancel the input reactance, the loop antenna must be used in a state where the efficiency of the antenna system is extremely poor. There was a problem that had to be.
[0008]
Therefore, the present invention can be used for a wireless device using a high-frequency wave of a very high frequency band or more, can be manufactured at low cost, and can improve the antenna characteristics and the sensitivity, performance, and stability of the wireless device. An object is to provide a portable wireless device using the same.
[0009]
[Means for Solving the Problems]
To achieve the above object, an antenna for a portable wireless device according to the invention of claim 1 is a portable wireless device antenna used as a transmitting / receiving antenna of a portable wireless device worn by a user by a band portion provided on a main body. At
In the longitudinal direction of the band portion,
A first feeding antenna element conductor, which is a plastic semiconductor and is fed from the center by a feeding unit for supplying power so that the distribution of current flowing in the longitudinal direction of the conductor is symmetric with respect to the center; When,
The power supply unit feeds the power from the center point so that the distribution of the current flowing in the longitudinal direction of the dielectric is symmetrical with respect to the stop point at a predetermined interval so as to be parallel to the first feed antenna element conductor. And a second feeding antenna element conductor which acts as an antenna having a different phase with respect to the first feeding antenna element conductor .
[0010]
In a preferred embodiment, a phase means may be provided between the second feeding antenna element conductor and the feeding section, for example.
In a preferred embodiment, the second feed antenna element conductor may be integrally formed with the first feed antenna element conductor, for example.
[0019]
[Action]
According to the present invention, the first power supplied from the central point is made of a plastic dielectric material in the longitudinal direction of the band for attaching the main body to the user so as to be symmetric with respect to the central point of the flowing current distribution. And a predetermined distance so as to be parallel to the first feeding antenna element and the first feeding antenna element, so that the distribution of current flowing in the longitudinal direction of the dielectric is symmetrical with respect to the stop point. A second feeding antenna element conductor, which is fed from the central point by the unit and acts as an antenna having a different phase with respect to the feeding antenna element conductor, to form a dipole antenna. Therefore, it can also be used for wireless devices that use high-frequency waves over the ultrashort wave band, and there is no need to configure a loop, which simplifies the structure and manufacturing, and does not change the antenna length. It is possible to improve the sensitivity, performance, and stability of the wireless device.
Further, even when the distance between the first feeding antenna element conductor and the second feeding antenna element conductor cannot be ensured due to the restriction of the band size (width), it is possible to obtain appropriate antenna characteristics by shifting the phase excessively. Can be.
[0020]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a wristwatch-type wireless device will be described as an example of a portable wireless device.
A. First embodiment A-1. FIG. 1A is a front view showing a configuration of a wristwatch-type wireless device to which an antenna for a portable wireless device according to a first embodiment of the present invention is applied, and FIG. 1 is a cross-sectional view illustrating a configuration of a wristwatch-type wireless device to which an antenna for a portable wireless device according to an embodiment is applied. In the figure, a wristwatch-type wireless device is roughly divided into a main body 1 in which electronic components such as a clock function and a wireless function are stored, band portions 2a and 2b for fixing the main body portion 1 to an arm, and a band portion. A buckle part 3 is provided at one end of the band part 2a to stop the two parts 2a and 2b from each other. As described above, the main body 1 has built-in electronic components, and a display unit 1b composed of an LCD or the like is provided on the upper surface thereof. Further, on both sides of the main body 1, switches 1c, 1c for operating mode, display switching, and the like are provided.
[0021]
Next, the band portion 2a is provided with a play ring 4 into which one end of the other band portion 2b is inserted when the wristwatch wireless device is worn on an arm and fixed. The band portion 2b is provided with a plurality of stop holes 5, 5,... In which the protruding rods 3a, which are components of the buckle portion 3, are inserted. The buckle portion 3 includes the protruding bar 3a, and a beautiful lock 3b for locking the protruding bar 3a and locking the inserted band portion 2b.
[0022]
The above-mentioned main body 1 is provided with a radio circuit section 6 and conductive power supply terminals 7a and 7b as components related to the present invention. The radio circuit section 6 supplies power to antenna element conductors 10a and 10b, which will be described later, while an input / output terminal for extracting received power received by the antenna element conductors 10a and 10b protrudes. Are electrically and physically fixed to the pedestals 11a and 11b with solder or the like. One ends of the power supply terminals 7a, 7b are also electrically and physically fixed to the pedestals 11a, 11b by solder or the like in the longitudinal direction of the band portions 2a, 2b.
[0023]
The other end of the power supply terminal 7a is electrically and physically fixed to one end of an antenna element conductor 10a extending in the longitudinal direction inside the band portion 2a by a conductive screw 7c or the like. On the other hand, the other end of the power supply terminal 7b is electrically and physically fixed to one end of the antenna element conductor 10b extending in the longitudinal direction inside the band portion 2b by a screw 7d. Each of the antenna element conductors 10a and 10b is made of a plastic conductor such as a metal plate, a metal thin film, or an electric wire. Since the power supply terminals 7a and 7b are provided between the main body 1 and the movable band portions 2a and 2c, the power supply terminals 7a and 7b are made of a flexible base material or the like.
[0024]
A-2. Next, FIG. 2A is a conceptual diagram showing a schematic configuration of the above-described antenna, and FIG. 2B is a circuit diagram showing an equivalent circuit of the antenna. In the figure, the sum of the length of the feed element 7a and the length of the antenna element conductor 10a is one antenna length L1 of the band antenna according to the first embodiment.
[0025]
(Equation 1)

[0026]
By doing so, the configuration is equivalent to the configuration of a so-called half-wavelength dipole antenna (hereinafter, referred to as a half-wavelength antenna). In general, a half-wave antenna draws an omnidirectional directional pattern that is symmetric about the antenna axis and equidistant in a direction perpendicular to the antenna. The input impedance of the half-wave antenna is represented by the following equation.
[0027]
(Equation 2)

[0028]
Here, 2L (= 2L1): total antenna length, ρ: wire diameter (radius), k = 2π / λ, λ: wavelength, We: wave impedance. Normally, the resistance R of a half-wavelength antenna having a total length of 2L = λ / 2 is approximately proportional to the square of the length, and decreases as the total length of 2L decreases, and the input reactance X changes substantially linearly with a change in length. When the total length 2L is short, the larger the wire diameter ρ, the larger the wire diameter ρ. In general, it is more convenient for the input impedance to be close to a pure resistance in order to apply to an actual antenna. For this purpose, it is necessary to make the total antenna length 2L slightly shorter than the half-wavelength λ / 2 from the above equation (2). You can see that there is. That is, one antenna length L (= L1) may be shortened by about 0.9 to 0.95 of λ / 4.
[0029]
Further, the radiated power Wr in the half-wave antenna is represented by the following equation.
[0030]
(Equation 3)

[0031]
Further, the radiation resistance Rr is represented by the following equation from the input impedance Z described above.
[0032]
(Equation 4)

[0033]
Further, the directivity gain Gd is
[0034]
(Equation 5)

[0035]
It is well known that
[0036]
B. Second embodiment B-1. Next, FIG. 3A is a conceptual diagram showing a schematic configuration of an antenna according to a second embodiment of the present invention, and FIG. 3B is a circuit diagram showing an equivalent circuit of the antenna. It is. In the figure, two antenna element conductors 12a, 12b, 13a, 13b extending in the longitudinal direction are respectively incorporated in the band portions 2a, 2b at a distance d, and the U-shaped power supply terminals 14a, It is electrically connected at 14b. One antenna length L1 of the band antenna according to the second embodiment is obtained by adding the length of the feed element 14a (14b) and the length of the antenna element conductor 10a (10b). Thus, in the second embodiment, the antenna is constituted by a plurality of half-wavelength antenna elements.
[0037]
In the above-described configuration, the input impedance of an antenna in which two identical half-wavelength antennas are arranged at an interval of d is expressed by the following equation.
[0038]
(Equation 6)

[0039]
The mutual impedance Z12 (= R12 + jX12) is represented by the following equation.
[0040]
(Equation 7)

[0041]
Thus, in the antenna according to the second embodiment, the mutual impedance Z12 is added in series to the input impedance. Here, in order to set the reactance component X12 to "0", that is, to make it a pure resistance, d / (λ / 4) = 0.5 or 2.8 and d = λ / 8 or 0.7λ. Just fine. That is, the distance d between the antenna element conductors 12a and 12b and the antenna element conductors 13a and 13b needs to be about ８ wavelength or about 0.7 of one wavelength. In this case, the gain Gh in the maximum radiation direction is smaller than that of the half-wavelength antenna according to the first embodiment described above.
[0042]
(Equation 8)

[0043]
Therefore, when the interval d is about 2.5 to 3 times λ / 4, the gain can be increased by 4 to 5 dB.
[0044]
C. Modified Example of Second Embodiment FIG. 4A is a conceptual diagram showing a schematic configuration of an antenna according to a modified example of the above-described second embodiment, and FIG. 4B shows an equivalent circuit of the antenna. It is a circuit diagram. In the figure, substantially U-shaped antenna element conductors 15a, 15b extending in the longitudinal direction are built in the band portions 2a, 2b, respectively, and are electrically connected by feed terminals 16a, 16b. In the antenna composed of the antenna element conductors 15a and 15b and the feeding terminals 16a and 16b, the length of the element when operating effectively differs from the lengths L1 and L2 (L1 <L2), and the distance between them is only the distance d. is seperated. The characteristics of this antenna are the same as those shown in FIG.
[0045]
D. Third Embodiment Next, FIG. 5A is a conceptual diagram showing a schematic configuration of an antenna according to a third embodiment of the present invention. FIG. 5B is a circuit diagram illustrating an equivalent circuit of the antenna, and FIG. 5C is a conceptual diagram schematically illustrating the equivalent circuit. In the figure, two antenna element conductors 17a, 18a, 17b, 18b extending in the longitudinal direction are respectively incorporated in the band portions 2a, 2b at a distance d, and each of them has a feed terminal 20a-20d. It is electrically connected to the wireless circuit section 6 which is a power supply section via the power supply section. In addition, a phase shifter 21 is interposed between the power supply terminal 6 and the power supply terminal 20b connected to the antenna element conductor 18a, and the phase shifter 21 is used instead of the in-phase half-wavelength antenna. , And act as half-wavelength antennas having different phases.
[0046]
In the third embodiment, in the above-described antenna shown in FIGS. 3 and 4, when the distance d cannot be ensured due to the restriction of the dimensions (width) of the band portions 2a and 2b, the phase as shown in FIG. Is applied to the antenna element conductors 18a and 18b, so that an appropriate antenna characteristic (for example, 5λ / 8 to 3λ / 4 with a large gain in the interval d) can be obtained even if the interval d is shortened. Therefore, an antenna equivalent to those of the first and second embodiments can be formed.
[0047]
E. FIG. Fourth Embodiment Next, FIG. 6A is a conceptual diagram showing a schematic configuration of an antenna according to a fourth embodiment of the present invention, and FIG. 6B is a circuit diagram showing an equivalent circuit of the antenna. . In the figure, two antenna element conductors 21a, 22a, 21b, 22b extending in the longitudinal direction are respectively incorporated in the band portions 2a, 2b at a distance d, and a pair of antenna element conductors 21a, 21b are provided. Only the power supply terminals 23a and 23b are electrically connected to the wireless circuit unit 6 serving as a power supply unit. The other antenna element conductors 22a and 22b are connected in series via the load ZL, and are disposed (at an interval d) near the fed antenna element conductors 21a and 21b. Since a strong electromagnetic field is generated in the vicinity of the fed antenna element conductors 21a and 21b, if the antenna element conductors 22a and 22b are arranged near the antenna element conductors 21a and 21b, a current flows without direct power supply, and Act as That is, the unpowered antenna element conductors 22a, 22b act as "reflectors" or "directors".
[0048]
The input impedance of the entire antenna described above, that is, the input impedance viewed from the terminals of the antenna element conductors 21a and 21b is expressed by the following equation.
[0049]
(Equation 9)

[0050]
The gain Gh (θ, φ) for a half-wavelength antenna composed of the antenna element conductors 21a and 21b is expressed by the following equation.
[0051]
(Equation 10)

[0052]
Therefore, the input impedance and the gain of the half-wave antenna can be changed by changing the value of the load ZL inserted between the non-feeding antenna element conductors 22a and 22b. If the load ZL is adjusted so as to increase the gain in the direction of φ = 0, the antenna element conductors 22a and 22b act as “directors”, and the load ZL is increased so as to increase the gain in the direction of φ = 80. When adjusted, the element conductors 22a, 22b act as "reflectors".
[0053]
F. Modification of Fourth Embodiment Next, FIG. 7A is a conceptual diagram showing a schematic configuration of an antenna according to a modification of the above-described fourth embodiment, and FIG. 7B shows an equivalent circuit of the antenna. FIG. In the present modification, as shown in the figure, the load ZL is set to "0", the non-feeding antenna element conductors 22a and 22b are short-circuited, and a "reflector" of a so-called "Yagi-Uda antenna" is provided. In this case, as is well known, by changing the length of the non-feeding antenna element conductors 22a and 22b instead of the load ZL, the same effect as changing the load ZL is obtained. That is, the length L2 of the parasitic antenna element conductors 22a, 22b is made longer or shorter than the half-wavelength antenna (2L1 = λ / 2, L1 = λ / 4) composed of the antenna element conductors 21a, 21b. When the length is changed, the change in the resistance of the self-impedance of one conductor whose overall length is close to a half wavelength is small, but the change in the reactance is large. Further, the mutual impedance Z21 does not change much due to the difference in the length L2 of the non-feeding antenna element conductors 22a and 22b. Therefore, if the length L2 is changed, it becomes equivalent to the fact that only the reactance X22 changes.
[0054]
That is, when the length L2 of the parasitic antenna element conductors 22a and 22b is λ / 4 (that is, the total length 2L2 is λ / 2), the antenna element conductors 22a and 22b function as a “reflector” when the length is 1 or more times, and the frontal gain is increased. Is reduced by about 6 dB, while when the length L2 is shorter than λ / 4 (that is, the entire length 2L is a half wavelength) by about 0.8 to 0.9, the frontal gain increases by 2 to 3 dB, and “waveguide” Acts as a vessel. Also, the thicker the antenna element conductor, the shorter the length of the waveguide.
[0055]
F. Another Modification of the Fourth Embodiment Next, FIG. 8A is a conceptual diagram showing a schematic configuration of an antenna according to another modification of the above-described fourth embodiment, and FIG. 3 is a circuit diagram showing an equivalent circuit of FIG. In this modification, as shown in FIG. 8, instead of the parasitic antenna element conductors 22a and 22b shown in FIG. 7, the length of the antenna element conductors 21a and 21b constituting the half-wavelength antenna is 0.8 to 0. Non-feeding antenna element conductors 24a and 24b having a length as short as about .9 are provided at a distance d3. These parasitic antenna element conductors 24a and 24b function as "wave directors".
[0056]
F. Another Modification of the Fourth Embodiment FIG. 9A is a conceptual diagram showing a schematic configuration of an antenna according to another modification of the fourth embodiment described above, and FIG. It is a circuit diagram showing an equivalent circuit. In the figure, band portions 2c and 2d are wider bands than the above-mentioned band portions 2a and 2b, and are provided with two rows of holes. The band portions 2c and 2d include three antenna element conductors 25a, 26a, 27a, 25b, 26b and 27b, respectively, separated by a distance d3, and one pair of the antenna element conductors 25a and 25b The other two pairs of antenna element conductors 26a, 26b, 27a, and 27b are connected to the wireless circuit section 6 serving as a feeding section to form the above-described half-wave antenna. Make up. In this case, when the antenna element conductors 26a, 26b, 27a, and 27b function as a "wave director", the antenna element conductor 25a must have a directivity opposite to the direction of radio wave transmission (or reception). , 25b (including the feeder) and the antenna element conductors 26a, 26b may be interchanged.
[0057]
F. Another Modified Example of the Fourth Embodiment Next, FIG. 10A is a conceptual diagram showing a schematic configuration of an antenna according to another modified example of the above-described fourth embodiment, and FIG. 3 is a circuit diagram showing an equivalent circuit of FIG. In the figure, three antenna element conductors 30a, 31a, 32a, 30b, 31b, 32b are respectively built in the band portions 2c, 2d, and the antenna element conductors 31a, 31b substantially at the center are feeders. It is connected to a certain radio circuit section 6 and constitutes the half-wavelength antenna having the length L1 described above, and the antenna element conductors 30a and 30b are arranged near the antenna element conductors 31a and 31b with a distance d2 therebetween. The antenna element conductors 32a and 32b are disposed near the antenna element conductors 31a and 31b with a distance d3 therebetween.
[0058]
The effective length of the antenna element conductors 30a, 30b is longer than the length L1 of the half-wave antenna and is L2, and the antenna element conductors 32a, 32b are shorter and longer than the length L1 of the half-wave antenna. L3. The antenna element conductors 30a, 30b act as one reflector, and the antenna element conductors 32a, 32b act as one director. In other words, in this modification, a general three-element “Yagi-Uda antenna” is configured as a band antenna. In this modification, the input impedance and the gain can be changed by changing the distance d3 and the length L3 between the antenna element conductors 32a and 32b with respect to the half-wavelength antenna. The gain can be increased by increasing the number of directors. According to this modification, the gain can be increased by about 4 to 6 dB with the three elements (reflector + director + antenna) as compared with a normal half-wave antenna.
[0059]
【The invention's effect】
According to the present invention, in the longitudinal direction of the band portion for mounting the main body to the user, the conductor having plasticity, the center point so that the distribution of the current flowing in the longitudinal direction is symmetric with respect to the center point. The following effects can be obtained by providing a feed antenna element conductor fed from the antenna and forming a dipole antenna.
(1) Since a bar antenna is not used, it can be used for a wireless device using a high-frequency wave of a very high frequency band or more.
(2) Unlike a cord-type antenna that also serves as an earphone, there is no need to attach or unwind it at the time of use, thereby improving usability.
(3) Since no loop is formed, the structure and manufacture of the buckle portion are simplified, and the manufacture is easy.
(4) Since the antenna length is not affected by the thickness of the user's arm and the like, the antenna length does not change and the antenna length can be kept constant, so that the antenna characteristics and the sensitivity, performance, and stability of the wireless device can be improved. .
(5) Further, since the parameters of the antenna can be easily adjusted, desired reception sensitivity and stable reception and communication can be performed according to the use situation.
(6) Even if the distance between the first feeding antenna element conductor and the second feeding antenna element conductor cannot be ensured due to the restriction of the band size (width), the phase can be shifted excessively to obtain appropriate antenna characteristics. Can be obtained.
[Brief description of the drawings]
FIGS. 1A and 1B are a front view and a sectional view showing a configuration of a wristwatch-type wireless device to which an antenna for a portable wireless device according to a first embodiment of the present invention is applied.
FIG. 2 is a conceptual diagram showing a schematic configuration of an antenna according to the first embodiment and a circuit diagram showing an equivalent circuit.
FIG. 3 is a conceptual diagram showing a schematic configuration of an antenna according to a second embodiment of the present invention and a circuit diagram showing an equivalent circuit.
FIG. 4 is a conceptual diagram showing a schematic configuration of an antenna according to a modification of the second embodiment and a circuit diagram showing an equivalent circuit of the antenna.
FIG. 5 is a conceptual diagram, an equivalent circuit, and a conceptual diagram showing a schematic configuration of an antenna according to a third embodiment of the present invention.
FIG. 6 is a conceptual diagram showing a schematic configuration of an antenna according to a fourth embodiment of the present invention and a circuit diagram showing an equivalent circuit.
FIG. 7 is a conceptual diagram showing a schematic configuration of an antenna according to a modification of the fourth embodiment and a circuit diagram showing an equivalent circuit.
FIG. 8 is a conceptual diagram showing a schematic configuration of an antenna according to another modification of the fourth embodiment and a circuit diagram showing an equivalent circuit.
FIG. 9 is a conceptual diagram showing a schematic configuration of an antenna according to another modification of the fourth embodiment and a circuit diagram showing an equivalent circuit.
FIG. 10 is a conceptual diagram showing a schematic configuration of an antenna according to another modification of the fourth embodiment and a circuit diagram showing an equivalent circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main body part 2a, 2b Band part 3 Buckle part 1b Display part 1c, 1c Switch 4 Free ring 3a Rod 5 Hole 6 Radio circuit part 7a, 7b Feeding terminals 10a, 10b Antenna element conductor (feeding antenna element conductor)
11a, 11b Bases 12a, 12b Antenna element conductor (feeding antenna element conductor)
13a, 13b Antenna element conductor (second feeding antenna element conductor)
14a, 14b Feed terminals 15a, 15b Antenna element wires (feed antenna element wires, second feed antenna element wires)
16a, 16b Feed terminals 17a, 17b Antenna element conductor (feed antenna element conductor)
18a, 18b Antenna element conductor (second feeding antenna element conductor)
20a to 20d power supply terminal 21 phase shifter (phase shift means)
21a, 21b Antenna element conductor (feeding antenna element conductor)
22a, 22b Antenna element conductor (parasitic antenna element conductor, reflector)
23a, 23b Feeding terminal ZL Load 24a, 24b Antenna element conductor (parasitic antenna element conductor, director)
2c, 2d Band portions 25a, 25b Antenna element conductor (feeding antenna element conductor)
26a, 26b Antenna element conductors (a plurality of parasitic antenna element conductors, directors)
27a, 27b antenna element conductors (a plurality of parasitic antenna element conductors, directors)
30a, 30b antenna element conductors (a plurality of parasitic antenna element conductors, a second parasitic antenna element conductor)
31a, 31b Antenna element conductor (feeding antenna element conductor)
32a, 32b antenna element conductors (a plurality of parasitic antenna element conductors, a first parasitic antenna element conductor)

Claims (3)

By a band portion provided in the main body, in a portable wireless device antenna used as a transmitting and receiving antenna of the portable wireless device worn by the user,
In the longitudinal direction of the band portion,
A first feeding antenna element conductor, which is a plastic semiconductor and is fed from the center by a feeding unit for supplying power so that the distribution of current flowing in the longitudinal direction of the conductor is symmetric with respect to the center; When,
The power supply unit feeds the power from the center point so that the distribution of the current flowing in the longitudinal direction of the dielectric is symmetrical with respect to the stop point at a predetermined interval so as to be parallel to the first feed antenna element conductor. And a second feed antenna element conductor which acts as an antenna having a different phase with respect to the first feed antenna element conductor . It said second feeding antenna element conductor and the portable radio device antenna according to claim 1, characterized in that a phase means between the power source. It said second feeding antenna element conductors, the first according to claim 1 or 2 portable radio device antenna according to, characterized in that it is powered antenna element conductor and integrally molded.

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