JP2004336180A - Multiple frequency antenna and element thereof - Google Patents
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- JP2004336180A JP2004336180A JP2003125990A JP2003125990A JP2004336180A JP 2004336180 A JP2004336180 A JP 2004336180A JP 2003125990 A JP2003125990 A JP 2003125990A JP 2003125990 A JP2003125990 A JP 2003125990A JP 2004336180 A JP2004336180 A JP 2004336180A
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Abstract
Description
【0001】
【発明の属する技術分野】
本発明は、パソコン、PDA(携帯型情報機器)、携帯電話、あるいはVICSなどの情報端末機器等に内蔵させる多周波小型スロットアンテナあるいは無線LAN用多周波スロットアンテナ、さらには多周波スロットアンテナの放射電極の改良に関するものである。
【0002】
【従来の技術】
近年、無線LANあるいはBluetooth(近距離無線データ通信システム)搭載のPDA等においては、アンテナの小型化のため、使用無線周波数帯域の高域化のみでなく、多周波化が盛んになって来ている。
その、一例として、3周波以上に対応できる逆F形の多周波アンテナが提案されている(例えば、特許文献1参照。)。
ところが、この提案では、共振周波数帯域の数に対応した数の放射電極(単位放射導体)群、アース(GND)板、および短絡板等の少なくとも3個の要素を必要とするため、多周波になると、どうしても、寸法・スペースが大きくなってしまうという問題がある。他方、スペース削減のために放射電極間の間隔を狭くし過ぎると、干渉が起き易くなるという通信品質上の問題があり、小型化には、自ずと限界がある。さらには、放射電極は、強度に乏しい切片状の金属薄板であるため、アンテナ素子に同軸ケーブル等の給電線を取り付ける際の軽度の作業ミスによっても折り曲がってしまい、結果的には、アンテナの特性を悪化させてしまうという問題もあった。
これに対して、一枚の金属板に単一のスロットが放射電極として配設された単周波受信用のスロットアンテナが提案されている。このアンテナは構造が簡素化され、上記した強度の問題も解消されることから、最近注目されている(例えば、特許文献2参照。)。
ただ、この文献では、多周波用のアンテナ構造についての開示はなく、ましてや多周波用アンテナにおいて多周波に渡ってVSWRを最小化し送受信特性の向上及び受信感度(Gain)の向上といった要求特性を満足させるような方策についても何等認識されていない。
【0003】
【特許文献1】
特開2000−68736号公報
【特許文献2】
特開2002−84128号公報
【0004】
【発明が解決しようとする課題】
したがって、本発明の課題は、パソコン、あるいはPDA等の情報端末機器等の内部に組込む2周波数以上の多周波に対応する多周波スロットアンテナあるいは無線LAN用多周波スロットアンテナにおいて、多周波に渡って電圧定在波比(VSWR)が小さく送受信特性並びに受信感度に優れるとともに小型化が実現された多周波アンテナ素子および多周波アンテナを提供することにある。
【0005】
【課題を解決するための手段】
本発明者等は、最も低いかまたは高い周波数に対応するスロットの長手方向の外周部で切り込みのVSWRが最小となる箇所を偏心給電点とし、しかも偏心給電点を通る仮想線に沿ってスロット群を相似的に配設することにより、上記の課題を解決するに至った。
【0006】
かくして、本発明によれば、導電性基材に、互いに長さの異なる複数個のスロット群が放射電極群として並置状態で配設され、これにより2周波以上の動作機能を付与された多周波アンテナ素子において、最も低いか又は高い周波数に対応するスロットの長手方向の外周部(ただし、該長手方向の中点に対応する外周部を除く)で該切り込みのVSWRが最小となる箇所ないしその近傍を偏心給電点とし、そして該偏心給電点を通り且つ該スロット群と直交する仮想線に沿ってこれらスロット群が相似的に配設されていることを特徴とする多周波アンテナ素子及び多周波アンテナが提供される。
【0007】
【発明の実施の形態】
以下、本発明を、2周波に対応するアンテナの例について説明する。
図1は、2周波に対応する本発明のアンテナ素子において、放射電極群としてのスロット群(この例では2個)の配設態様の一例を示す平面図である。
図2は、図1に示した本発明のアンテナ素子を情報端末機器内蔵用多周波アンテナに適用した例を示す部分斜視図である。
図1〜図2において、(1)は平板状の導電性基材、(2)は導電性基材(1)の一部を切り抜いて形成された第1のスロット(第1の周波数に対応する第1放射電極)、(3)は、同様に導電性基材(1)の一部をスロット(2)の長さより短かくなるように切り抜いて形成された第2のスロット(第2の周波数に対応する第2放射電極)、(4)は高周波同軸ケーブル、(4a)はその内部導体、(4b)はその外部導体、(5)は導電性基材(1)の取り付け穴、(G)はアースポイント、(M)は偏心給電点、(P)は偏心給電点を通り且つスロット群と直交する仮想線、(L1)はスロット(2)の長さ(全長)、(L2)はスロット(3)の長さ(全長)、(W)はスロット(2)、(3)の幅、(D)はスロット(2)とスロット(3)との隣接間隔、(a1)及び(a2)は仮想線(P)によって分割される一方の側の各スロット長、(b1)及び(b2)は同じく仮想線(P)によって分割される他方の側の各スロット長、そして、(C)は各スロットの中点である。
【0008】
本発明で特徴的なことは、スロット群を偏心給電点の位置に関連して相似的に配設することにより、アンテナ素子全体としての複数の共振点近傍でのVSWRを最小に維持し、送受信特性を向上させ、しかも、アンテナの受信感度(Gain)も格段に向上させたことにある。
これらの点について、図1を参照しながら、さらに詳細な説明をする。
先ず、並置状態で配設されたスロット(2)及びスロット(3)のうち、スロット(2)の外周部で該スロットのVSWRが最小となる箇所ないしその近傍(M)を偏心給電点とする。そして、該偏心給電点(M)を通り且つスロット(2)及び(3)と直交するような仮想線(P)を描いた際に、該仮想線(P)に沿ってスロット(2)及び(3)を相似的に配設する。その際、該仮想線(P)によって分割される一方の側のスロット長(a)と他方の側のスロット長(b)との比がa:b=1:1.5〜1:4.5の範囲のある限り、所望のアンテナ機能が達成される。この比の好ましい範囲は、a:b=1:2〜1:3.5である。
偏心給電点(M)は、前述のように、スロット(2)又は(3)の外周部で、スロット(2)又は(3)のVSWRが最小となる位置あるいはその近傍に設定される。この場合の偏心量は、スロット(2)の長手方向の中点(C)を0点とするX,Yの座標軸の第2象限又はスロット(3)の長手方向の中点(C)を0点とするX,Yの座標軸の第1象限において、X軸方向、Y軸方向ともに20 %〜40 %の範囲にあるのが好ましい。ここで、スロットのその他の要件について述べると、スロット(2)の長さ(L1)は35〜45mm、スロット(3)の長さ(L2)は63〜73mmの範囲から適宜選定される。このときの各スロットの幅(W)は0.5mm〜5mmの範囲から適宜採択すればよい。また、スロット(2)とスロット(3)との間の空間的な配設(位相)は、必ずしも平行である必要はないが、スペース効率の点から平行配設が好ましい。スロット(2)とスロット(3)との隣接間隔(D)が、小さ過ぎると干渉が生じ、逆に該間隔(D)が大き過ぎるとスペース効率が悪くなる。このことを勘案すると、該隣接間隔(D)は0.5mm〜10mmの範囲とすることが好ましい。
さらに、導電性基材(1)に配設されるスロットは、多周波受信ということから、共振周波数帯域の数に対応した複数個、通常は2または3個配設される。
本発明において、導電性基材としては、洋白(白銅)、銅、鉄、あるいは黄銅等の導電性の金属基材が好ましい。その中でも洋白(白銅)が強度、加工性、及び耐腐食性に優れているので、特に好ましい。基材の形状は、図示したように通常は平板状で採用される。この“平板状”の典型的な例は金属板である。その際、安定した動作を確保するためには、少なくとも70mm2以上の面積が必要とされる。実用的には、140mm2〜420mm2の範囲とすることが望ましい。また、その厚さについては格段の制約はないが、強度を考慮して0.3mm〜3mmの範囲内で適宜選択すればよい。また、導電性基材としては、上述した金属のほか、樹脂フィルム上に金属を蒸着させた金属蒸着フィルム、あるいは銅箔等の導電部を設けた平板状基材であってもよい。そして、これらの基材については、切り込みのほかにエッチングによりスロットを形成してもよい。
以上、図1を通して本発明のアンテナ素子について説明したが、該素子から実際に多周波アンテナを構成する際は、図2に示すようにスロット群(2)及び(3)を挟んで偏心給電点(M)と反対側にアースポイント(G)を付設する。このアースポイント(G)は、仮想線(P)上あるいはその近傍、またはスロット(3)中点(C)を0点とするX、Yの座標軸の第4象限において、X軸方向及びY軸方向に共に0〜20%偏心した箇所に設ければよい。そして、これらの偏心給電点(M)及びアースポイント(G)には、給電のため、高周波同軸ケーブル(4)等の給電部材を接続すればよい。このとき、高周波同軸ケーブル(4)の内部導体(4a)は偏心給電点(M)に他方、外部導体(4b)はアースポイント(G)に接続される。高周波同軸ケーブル(4)としては、周知のフッ素樹脂被覆等の高周波同軸ケーブルが採用される。高周波同軸ケーブル(4)を偏心給電点(M)及びアースポイント(G)に接続するには、ハンダ付あるいは超音波接続等を利用すればよい。
最後に、本発明のアンテナを情報端末機器に取付ける際には、取り付け穴(5)を利用することにより簡単に取り付けができる。
【0009】
以下に、図1に示した、2周波に対応する多周波素子を適用した情報端末機器内蔵用アンテナの具体例を示す。
先ず、縦70mm、横50mm、厚さ0.4mmの洋白板からなる平板状導電性基材(1)の中央部に簡易プレス機により2.45GHz帯に対応した長さ68mm、幅1mmのスロット(2)を設けて第1放射電極を形成した。このとき、スロット(2)のVSWRが最小となる偏心給電点(M)の位置は、スロット(2)の中点(C)を0点とするX、Yの座標軸の第2象限において、X軸方向に15%、Y軸方向に共に30%偏心した箇所であった。したがって、スロット(2)の偏心給電点(M)を通り且つ該スロットと直交する仮想線(P)によって分割される一方の側のスロット長(a1)及び他方の側のスロット長(b1)は、ぞれぞれ19mm(a1)及び49mm(b1)であり、a1:b1=1:2.58となる。
次に、図1に示すように、スロット(2)の右側に、5.25GHz帯に対応する第2放射電極として、長さ(L2)が40mm、幅(W)が1mmのスロット(3)を1mmの隣接間隔(D)で並置した。このとき、仮想線(P)によって分割される一方の側のスロット長(a2)と他方の側のスロット長(b2)は、ぞれぞれ11.4mm(a2)及び28.6mm(b2)であり、との比はa2:b2=1:2.50とし、両スロットを仮想線(P)に沿って相似的に並置・配設した。さらに、図2に示すように、スロット(3)の中点(C)を0点とするX、Yの座標軸の第4象限において、X軸方向及びY軸方向に共に15%偏心した箇所にアースポイント(G)を設けた。
最後に、上記の給電点(M)及びアースポイント(G)に、外径0.93mm、導体径0.24mmのフッ素樹脂(PFA)同軸ケーブル(4)の内部導体(4a)及び外部導体(4b)をそれぞれハンダにより接続することにより、2周波に対応する情報端末機器内蔵用アンテナを得た。
以下、表1に本発明の効果を従来例(比較例)との比較において説明する。
ここで、実施例は仮想線(P)によって分割される一方の側のスロット長(a)と他方の側のスロット長(b)との比がa:b=1:2.5の場合を示し、比較例1はa:b=1:5の場合を示し、比較例2はa:b=1:1の場合を示している。なお比較例での周波数等のその他の条件は本発明と同一とした。
【表1】
上記、表1から明らかに、本発明が多周波(第1周波数及び第2周波数)に渡ってVSWRが小さく送受信特性に優れるとともにGainまでも改善された高能率のアンテナが得られることが判る。
このようなアンテナは、パソコンをはじめとしてPDA等、各種情報端末機器を始めとし、家電製品あるいは自動車関連機器へも内蔵できる。もちろん、本発明の思想の範囲内であれば、種々の変更および応用が可能であることは言うまでもない。
【0010】
【発明の効果】
本発明によれば、従来と比較してVSWRが小さく送受信特性並びにGainが大幅に向上し、しかも小型化が実現された多周波アンテナ素子が提供される。その結果、該素子から得られるアンテナはパソコン等の情報端末機器内蔵用としてその機能を如何なく発揮するという格別顕著な効果を奏する。
【図面の簡単な説明】
【図1】2周波に対応する本発明のアンテナ素子において、放射電極群としてのスロット群の配設態様の一例を示す平面図である。
【図2】図1に示した本発明のアンテナ素子を情報端末機器内蔵用多周波アンテナに適用した例を示す部分斜視図である。
【符号の説明】
1 導電性基材
2 第1放射電極を形成するスロット
3 第2放射電極を形成するスロット
4 高周波同軸ケーブル
4a 高周波同軸ケーブル(4)の内部導体
4b 高周波同軸ケーブル(4)の外部導体
5 取り付け穴
G アースポイント
M 偏心給電点
P 偏心給電点(M)を通り且つスロット群(2)、(3)に直交する仮想線
a1 仮想線(P)によって分割されるスロット(2)の 一方の側のスロット長
b1 仮想線(P)によって分割されるスロット(2)の他方の側のスロット長
a2 仮想線(P)によって分割されるスロット(3)の 一方の側のスロット長
b2 仮想線(P)によって分割されるスロット(3)の他方の側のスロット
L1 スロット(2)の長さ
L2 スロット(3)の長さ
W スロット(2)、(3)の幅
C スロット(2)、(3)の中点
D スロット(2)とスロット(3)との隣接間隔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a small multi-frequency slot antenna or a multi-frequency slot antenna for a wireless LAN incorporated in a personal computer, a PDA (portable information device), a mobile phone, or an information terminal device such as a VICS, and radiation from a multi-frequency slot antenna. The present invention relates to improvement of an electrode.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in a PDA or the like equipped with a wireless LAN or Bluetooth (short-distance wireless data communication system), in order to reduce the size of an antenna, not only the use of a higher frequency band but also the use of multiple frequencies has become popular. I have.
As one example, an inverted-F multi-frequency antenna capable of coping with three or more frequencies has been proposed (for example, see Patent Document 1).
However, in this proposal, at least three elements such as the number of radiating electrodes (unit radiating conductors) corresponding to the number of resonance frequency bands, a ground (GND) plate, and a short-circuit plate are required. In this case, there is a problem that the size and the space are inevitably increased. On the other hand, if the spacing between the radiation electrodes is made too narrow to reduce the space, there is a problem in communication quality that interference is likely to occur, and there is naturally a limit to miniaturization. Furthermore, since the radiation electrode is a section-shaped thin metal plate with low strength, it is bent by a slight work error when attaching a feed line such as a coaxial cable to the antenna element, and as a result, the antenna There is also a problem that characteristics are deteriorated.
On the other hand, a slot antenna for single frequency reception in which a single slot is provided as a radiation electrode in one metal plate has been proposed. This antenna has recently attracted attention because its structure is simplified and the above-mentioned problem of strength is solved (for example, see Patent Document 2).
However, this document does not disclose a multi-frequency antenna structure, and moreover, a multi-frequency antenna satisfies required characteristics such as minimizing VSWR over multiple frequencies and improving transmission / reception characteristics and reception sensitivity (Gain). There is no recognition of any measures that could cause them to do so.
[0003]
[Patent Document 1]
JP 2000-68736 A [Patent Document 2]
JP-A-2002-84128
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a multi-frequency slot antenna for two or more frequencies or a multi-frequency slot antenna for a wireless LAN incorporated in a personal computer or an information terminal device such as a PDA. It is an object of the present invention to provide a multi-frequency antenna element and a multi-frequency antenna having a small voltage standing wave ratio (VSWR), excellent transmission / reception characteristics, excellent reception sensitivity, and miniaturization.
[0005]
[Means for Solving the Problems]
The present inventors set an eccentric feeding point at a position where the VSWR of the cut is minimum at the longitudinal outer peripheral portion of the slot corresponding to the lowest or high frequency, and furthermore, a group of slots along an imaginary line passing through the eccentric feeding point. By disposing them in a similar manner, the above problem has been solved.
[0006]
Thus, according to the present invention, a plurality of slots having different lengths are arranged side by side as a group of radiating electrodes on a conductive substrate, thereby providing a multi-frequency device having an operation function of two or more frequencies. In the antenna element, at or near the location where the VSWR of the cut is minimum at the outer peripheral portion in the longitudinal direction of the slot corresponding to the lowest or highest frequency (excluding the outer peripheral portion corresponding to the midpoint in the longitudinal direction) A multi-frequency antenna element and a multi-frequency antenna, wherein the slots are arranged in a similar manner along an imaginary line passing through the eccentric feeding point and orthogonal to the slots. Is provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with respect to an example of an antenna corresponding to two frequencies.
FIG. 1 is a plan view showing an example of an arrangement of slots (two in this example) as radiation electrode groups in the antenna element of the present invention corresponding to two frequencies.
FIG. 2 is a partial perspective view showing an example in which the antenna element of the present invention shown in FIG. 1 is applied to a multi-frequency antenna for a built-in information terminal device.
1 and 2, (1) is a flat conductive base material, and (2) is a first slot (corresponding to a first frequency) formed by cutting out a part of the conductive base material (1). Similarly, the first radiation electrode (3) is formed by cutting out a part of the conductive substrate (1) so as to be shorter than the length of the slot (2). (4) is a high-frequency coaxial cable, (4a) is its inner conductor, (4b) is its outer conductor, (5) is a mounting hole of the conductive substrate (1), G) is an earth point, (M) is an eccentric feeding point, (P) is an imaginary line passing through the eccentric feeding point and orthogonal to the slot group, (L1) is the length (total length) of the slot (2), (L2) Is the length (full length) of the slot (3), (W) is the width of the slots (2) and (3), and (D) is the slot (2) and the slot. (A1) and (a2) are the respective slot lengths on one side divided by a virtual line (P), and (b1) and (b2) are also divided by the virtual line (P). The length of each slot on the other side, and (C) is the midpoint of each slot.
[0008]
A characteristic of the present invention is that the VSWRs near the plurality of resonance points as the whole antenna element are kept to a minimum by arranging the slots in a similar manner in relation to the position of the eccentric feeding point. The characteristics are improved, and the receiving sensitivity (Gain) of the antenna is also significantly improved.
These points will be described in more detail with reference to FIG.
First, of the slots (2) and (3) arranged in a juxtaposed state, a portion where the VSWR of the slot is minimum or its vicinity (M) on the outer peripheral portion of the slot (2) is defined as an eccentric feeding point. . Then, when a virtual line (P) passing through the eccentric feeding point (M) and orthogonal to the slots (2) and (3) is drawn, the slots (2) and (4) are drawn along the virtual line (P). (3) is similarly arranged. At this time, the ratio of the slot length (a) on one side divided by the virtual line (P) to the slot length (b) on the other side is a: b = 1: 1.5 to 1: 4. As long as there is a range of 5, the desired antenna function is achieved. The preferred range of this ratio is a: b = 1: 2-1: 3.5.
As described above, the eccentric feeding point (M) is set at or near the position where the VSWR of the slot (2) or (3) is minimum on the outer peripheral portion of the slot (2) or (3). In this case, the amount of eccentricity is determined by setting the midpoint (C) in the second quadrant of the X and Y coordinate axes having the midpoint (C) in the longitudinal direction of the slot (2) as a zero point or the midpoint (C) in the longitudinal direction of the slot (3) to 0. In the first quadrant of the X and Y coordinate axes as the points, it is preferable that both the X-axis direction and the Y-axis direction be in the range of 20% to 40%. Here, regarding other requirements of the slot, the length (L1) of the slot (2) is appropriately selected from the range of 35 to 45 mm, and the length (L2) of the slot (3) is appropriately selected from the range of 63 to 73 mm. The width (W) of each slot at this time may be appropriately selected from the range of 0.5 mm to 5 mm. The spatial arrangement (phase) between the slot (2) and the slot (3) is not necessarily parallel, but is preferably parallel in view of space efficiency. If the adjacent distance (D) between the slot (2) and the slot (3) is too small, interference occurs. Conversely, if the distance (D) is too large, the space efficiency deteriorates. Considering this, it is preferable that the adjacent distance (D) is in the range of 0.5 mm to 10 mm.
In addition, a plurality of slots, usually two or three, corresponding to the number of resonance frequency bands are provided in the conductive base material (1) because of multi-frequency reception.
In the present invention, the conductive substrate is preferably a conductive metal substrate such as nickel silver (white copper), copper, iron, or brass. Among them, nickel white (white copper) is particularly preferable because of its excellent strength, workability, and corrosion resistance. The shape of the substrate is usually a flat plate as shown in the figure. A typical example of this “flat” is a metal plate. At this time, an area of at least 70 mm2 is required to ensure stable operation. Practically, it is desirable to set the range of 140 mm2 to 420 mm2. The thickness is not particularly limited, but may be appropriately selected within the range of 0.3 mm to 3 mm in consideration of the strength. The conductive substrate may be a metal-deposited film obtained by depositing a metal on a resin film or a flat substrate provided with a conductive portion such as a copper foil, in addition to the above-described metals. And about these base materials, you may form a slot by etching other than cutting.
As described above, the antenna element of the present invention has been described with reference to FIG. 1. When an antenna is actually constructed from the element, as shown in FIG. 2, the eccentric feed points sandwich the slot groups (2) and (3) as shown in FIG. An earth point (G) is attached to the opposite side of (M). The earth point (G) is located on or near the virtual line (P), or in the fourth quadrant of the X and Y coordinate axes with the midpoint (C) of the slot (3) as the zero point, in the X-axis direction and the Y-axis direction. What is necessary is just to provide in the location which is 0-20% eccentric in both directions. Then, a power supply member such as a high-frequency coaxial cable (4) may be connected to the eccentric power supply point (M) and the earth point (G) for power supply. At this time, the inner conductor (4a) of the high-frequency coaxial cable (4) is connected to the eccentric feeding point (M), while the outer conductor (4b) is connected to the ground point (G). As the high-frequency coaxial cable (4), a well-known high-frequency coaxial cable such as a fluororesin coating is adopted. In order to connect the high-frequency coaxial cable (4) to the eccentric feeding point (M) and the earth point (G), soldering or ultrasonic connection may be used.
Finally, when the antenna of the present invention is mounted on the information terminal device, the antenna can be easily mounted by using the mounting hole (5).
[0009]
Hereinafter, a specific example of the information terminal device built-in antenna to which the multi-frequency element corresponding to two frequencies shown in FIG. 1 is applied is shown.
First, a slot having a length of 68 mm and a width of 1 mm corresponding to the 2.45 GHz band was formed by a simple press machine in the center of a flat conductive substrate (1) composed of a white plate having a length of 70 mm, a width of 50 mm and a thickness of 0.4 mm. (2) was provided to form a first radiation electrode. At this time, the position of the eccentric feeding point (M) at which the VSWR of the slot (2) becomes minimum is X in the second quadrant of the X and Y coordinate axes with the midpoint (C) of the slot (2) as zero. The eccentricity was 15% in the axial direction and 30% in the Y-axis direction. Therefore, the slot length (a1) on one side and the slot length (b1) on the other side, which are divided by an imaginary line (P) passing through the eccentric feeding point (M) of the slot (2) and orthogonal to the slot, are And 19 mm (a1) and 49 mm (b1), respectively, and a1: b1 = 1: 2.58.
Next, as shown in FIG. 1, a slot (3) having a length (L2) of 40 mm and a width (W) of 1 mm is provided on the right side of the slot (2) as a second radiation electrode corresponding to the 5.25 GHz band. Were juxtaposed at an adjacent distance (D) of 1 mm. At this time, the slot length (a2) on one side and the slot length (b2) on the other side divided by the virtual line (P) are 11.4 mm (a2) and 28.6 mm (b2), respectively. The ratio was set to a2: b2 = 1: 2.50, and both slots were similarly juxtaposed and arranged along the virtual line (P). Further, as shown in FIG. 2, in the fourth quadrant of the X and Y coordinate axes with the midpoint (C) of the slot (3) as the zero point, a position deviated by 15% in both the X-axis direction and the Y-axis direction. An earth point (G) was provided.
Lastly, the inner conductor (4a) and the outer conductor (4a) of the fluororesin (PFA) coaxial cable (4) having an outer diameter of 0.93 mm and a conductor diameter of 0.24 mm are provided at the feeding point (M) and the earth point (G). 4b) was connected by soldering, respectively, to obtain an information terminal device built-in antenna corresponding to two frequencies.
Hereinafter, the effects of the present invention are described in Table 1 in comparison with a conventional example (comparative example).
Here, the embodiment is a case where the ratio of the slot length (a) on one side divided by the virtual line (P) to the slot length (b) on the other side is a: b = 1: 2.5. Comparative Example 1 shows a case where a: b = 1: 5, and Comparative Example 2 shows a case where a: b = 1: 1. Other conditions such as the frequency in the comparative example were the same as those of the present invention.
[Table 1]
It is apparent from Table 1 that the present invention can provide a highly efficient antenna having a small VSWR over multiple frequencies (first frequency and second frequency), excellent transmission and reception characteristics, and improved gain.
Such an antenna can be built in various information terminal devices such as personal computers, PDAs, and the like, as well as in home electric appliances or automobile-related devices. Of course, various changes and applications are possible within the scope of the concept of the present invention.
[0010]
【The invention's effect】
According to the present invention, there is provided a multi-frequency antenna element in which the VSWR is small as compared with the related art, the transmission / reception characteristics and the gain are greatly improved, and the size is reduced. As a result, the antenna obtained from the element has a remarkably remarkable effect that it exhibits its function for use in information terminal devices such as personal computers.
[Brief description of the drawings]
FIG. 1 is a plan view showing an example of an arrangement mode of a slot group as a radiation electrode group in an antenna element of the present invention corresponding to two frequencies.
FIG. 2 is a partial perspective view showing an example in which the antenna element of the present invention shown in FIG. 1 is applied to a multi-frequency antenna for a built-in information terminal device.
[Explanation of symbols]
Claims (5)
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JP2003125990A JP4507507B2 (en) | 2003-04-30 | 2003-04-30 | Multi-frequency antenna |
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JP2003125990A JP4507507B2 (en) | 2003-04-30 | 2003-04-30 | Multi-frequency antenna |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009522838A (en) * | 2006-01-02 | 2009-06-11 | エヌエックスピー ビー ヴィ | Improved ultra-wideband notch antenna assembly for RF communication equipment |
JP2009239795A (en) * | 2008-03-28 | 2009-10-15 | Mitsumi Electric Co Ltd | Antenna device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05199031A (en) * | 1991-08-07 | 1993-08-06 | Alcatel Thomson Espace | Small-sized basic radio antenna |
JPH06283923A (en) * | 1993-03-26 | 1994-10-07 | Nippon Antenna Kk | Folded slot antenna with cavity |
US5539420A (en) * | 1989-09-11 | 1996-07-23 | Alcatel Espace | Multilayered, planar antenna with annular feed slot, passive resonator and spurious wave traps |
JP2002084128A (en) * | 2000-07-25 | 2002-03-22 | Internatl Business Mach Corp <Ibm> | Boxed-in slot antenna having space-saving configuration |
US6664932B2 (en) * | 2000-01-12 | 2003-12-16 | Emag Technologies, Inc. | Multifunction antenna for wireless and telematic applications |
-
2003
- 2003-04-30 JP JP2003125990A patent/JP4507507B2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5539420A (en) * | 1989-09-11 | 1996-07-23 | Alcatel Espace | Multilayered, planar antenna with annular feed slot, passive resonator and spurious wave traps |
JPH05199031A (en) * | 1991-08-07 | 1993-08-06 | Alcatel Thomson Espace | Small-sized basic radio antenna |
JPH06283923A (en) * | 1993-03-26 | 1994-10-07 | Nippon Antenna Kk | Folded slot antenna with cavity |
US6664932B2 (en) * | 2000-01-12 | 2003-12-16 | Emag Technologies, Inc. | Multifunction antenna for wireless and telematic applications |
JP2002084128A (en) * | 2000-07-25 | 2002-03-22 | Internatl Business Mach Corp <Ibm> | Boxed-in slot antenna having space-saving configuration |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009522838A (en) * | 2006-01-02 | 2009-06-11 | エヌエックスピー ビー ヴィ | Improved ultra-wideband notch antenna assembly for RF communication equipment |
JP2009239795A (en) * | 2008-03-28 | 2009-10-15 | Mitsumi Electric Co Ltd | Antenna device |
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