JP2004128742A - Antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized and inexpensive antenna capable of stable operations even when there is no conductive housing part in an antenna which is incorporated to the inside of information terminal equipment or the like such as a personal computer and a PDA. <P>SOLUTION: A conductive member (5) as a separate body for increasing the area of an earth electrode is stuck to the earth electrode (3). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a small antenna built in an information terminal device such as a personal computer, a PDA (portable information device), a mobile phone, or a VICS.
[0002]
[Prior art]
In recent years, there has been an increasing demand for miniaturization of dimensions in PDAs and the like equipped with a wireless LAN or Bluetooth (short-range wireless data communication system), and a conductive housing has been used as a ground electrode. It has been known. As one example, a built-in antenna of a mobile phone in which a conductive portion of a housing and a ground terminal (GND) are connected has been proposed. (For example, see Patent Document 1)
However, in this proposal, when the area of the conductive casing is small, there is a problem that the resonance frequency varies and the operation becomes unstable. In addition, there is a problem that this proposal cannot be adopted when there is no conductive casing.
[0003]
[Patent Document 1]
Japanese Patent No. 2908432 (Claims, FIG. 1)
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide an antenna incorporated in an information terminal device such as a personal computer or a PDA, which can operate stably even in the absence of a conductive casing, and is small and inexpensive. Is to provide.
[0005]
[Means for Solving the Problems]
The present inventors have paid attention to attaching a separate conductive member for increasing the area to the ground electrode portion, and have achieved the present invention.
[0006]
Thus, according to the present invention, the antenna element is opposed to the ground electrode via the short-circuit member, and at that time, a separate conductive member for increasing the area is attached to the ground electrode. A featured antenna is provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an example of the antenna of the present invention.
FIG. 2 is a perspective view showing an example in which the antenna of the present invention shown in FIG. 1 is mounted on a personal computer as an information terminal device.
1 and 2, (1) is an antenna, (2) is an antenna element, (3) is a ground electrode, and (4) is a short circuit for electrically connecting the antenna element (2) and the ground electrode (3). The member, (5) is a conductive member adhered to the ground electrode (3), and (6) is a high-frequency coaxial cable.
[0008]
What is characteristic of the present invention is that the earth electrode (3), which is usually made of a non-flexible material, is provided with a particularly flexible conductive member (5) that shares a function with the earth electrode (3). Has been added. By doing so, a stable operation of the antenna is ensured, and the space can be significantly reduced and the mounting step in a separate step can be omitted.
Hereinafter, this point will be described in more detail.
As shown in FIG. 1, the conductive member (5) in a plate state is adhered to the original ground electrode (3) and is electrically connected.
Here, in order to enable stable operation, the necessary minimum area (mm2) of the conductive member (5) is determined by the sum of the area of the ground electrode (3) and the area of the conductive member (5) is λ / 4 * λ. / 4 (λ is a wavelength). Therefore, if the area of the ground electrode (3) is originally somewhat smaller than the value of λ / 4 * λ / 4, the area of the conductive member (5) can be small. When a more stable operation is desired, it is desirable to increase the total sum of the ground electrode (3) and the conductive member (5), that is, to increase the area of the entire ground portion as far as space permits. At this time, the area ratio between the ground electrode (3) and the conductive member (5) is preferably such that the area of the conductive member (5) is in the range of 100% to 600% of that of the ground electrode (3). The material of the conductive member (5) is a thin plate made of a metal such as copper, aluminum, tin, or zinc, or a flexible resin such as a conductive tape of a synthetic resin base material (for example, a polyester base material) on which these metals are deposited. Although a member is preferably used, a conductive tape on which a metal is deposited is more preferable from the viewpoint of processability and flexibility.
The thickness of the conductive member (5) is appropriately selected from the range of 0.1 mm to 0.5 mm from the viewpoint of workability. As a means for sticking the conductive member (5) to the ground electrode (3), various fixing means such as caulking, soldering, or bonding can be adopted. Among them, sticking with an adhesive is preferable from the viewpoint of productivity. . The conductive member (5) may be attached to the ground electrode (3) in the same plane, bend at a certain angle, or bend to the back side, and the like. An arbitrary positional relationship can be selected in consideration of the above situation.
Next, the structure of the antenna itself will be described.
The antenna element (2) shown as a section is installed on the ground electrode (3) via a short-circuit member (4). The mode of the opposed installation may be a state in which both sides are angled, for example, a state in which the elevation angle is 90 degrees or less, in addition to the plane-parallel state in which the planes are spaced as illustrated. The length of the section serving as the antenna element (2) is set to 設定 of the adopted wavelength, and the width of the section is appropriately selected from the range of 1 mm to 5 mm. On the other hand, the thickness of the section is not particularly limited, and may be a thin plate-like thickness similar to a display panel fixing member such as a personal computer. Various metal members such as nickel-white (white copper), SUS, copper, iron, brass, and zinc are used as the material for forming the section, but nickel-white is used in view of workability, corrosion resistance, and solder adhesion. (White copper) is preferably employed.
As for the material of the ground electrode (3), various metal members such as nickel-white (white copper), SUS, copper, iron, brass, or zinc are used as in the case of the antenna element (2). In view of solder adhesion, nickel silver (white copper) is preferably used. Further, the inner conductor of the high-frequency coaxial cable (6) is connected to the inner conductor impedance matching point (S1) located at the antenna element (2), while the outer conductor is located at the ground electrode (3). It is connected to the impedance matching point (S2) (earth point). As the high-frequency coaxial cable (6), a known high-frequency coaxial cable such as a fluororesin coating is used. To connect the high-frequency coaxial cable (6) to the two impedance matching points (S1, S2), soldering or ultrasonic connection may be used.
[0009]
In the above-described embodiment, an example in which the number of antenna elements (radiation electrodes) is one is shown. However, as another embodiment, two or more pieces (extending portions) as the antenna element (2) are provided to provide two or more wavelengths. Of course, it is possible to correspond.
[0010]
A specific example in which the antenna of the present invention shown in FIG. 1 is applied to a personal computer as an information terminal device will be described below with reference to FIG.
First, a white earth electrode (3) having a thickness of 0.4 mm and an area of 150 mm2 was fixed to a side surface of a display panel fixing member of a personal computer by screwing. On this earth electrode (3), a piece-shaped antenna element (2) corresponding to a 5 GHz band of 0.4 mm in thickness, 2 mm in width, and 15 mm in length is formed as an earth electrode (3). They were opposed to each other via a short-circuit member (4) so as to be parallel at intervals of 2.5 mm. At that time, the antenna element (2) was fixed to the ground electrode (3) by soldering via the short-circuit member (4).
Further, on the end of the earth electrode (3), a copper vapor-deposited tape obtained by vapor-depositing copper to a thickness of 50 μm on a polyester substrate having a thickness of 0.14 mm, a width of 20 mm, a length of 30 mm, and an area of 600 mm 2 is formed. The conductive member (5) was adhered with a conductive adhesive (trade name “Scotch Brand Tape”, manufactured by Sumitomo 3M Limited). At that time, the dimensions of the adhesive portion of the tape were 4 mm in width and 20 mm in length, and were excluded from the above area. The total area of the ground part thus obtained, that is, the sum of the area of the ground electrode (3) and the area of the conductive member (5) is 750 mm2, and the area of the conductive member (5) at that time is equal to the ground electrode (3). ) Part corresponds to 400% of that.
Finally, the inner conductor and the outer conductor of a fluororesin (PFA) coaxial cable having an outer diameter of 0.93 mm and a conductor diameter of 0.24 mm are connected to the impedance matching points (S1, S2) by soldering, respectively, and connected to a personal computer. Completed the built-in.
In the above description, an example is shown in which the antenna of the present invention is incorporated in a personal computer as an information terminal device. However, the antenna can be used for home appliances or various information terminal devices such as a PDA, a mobile phone, and a VICS. It will be easily understood that it can be similarly incorporated into an automobile-related device. Of course, various changes and applications are possible within the scope of the concept of the present invention.
[0011]
【The invention's effect】
The antenna of the present invention can be easily built in these terminal devices. In particular, by adding and attaching a highly flexible conductive member to the ground electrode, it can be easily incorporated even when the installation location is narrow and cramped, or even when the equipment does not have a conductive housing. be able to. As a result, according to the present invention, it is possible to ensure a stable operation of the antenna, and to achieve a particularly remarkable effect that the problem of reducing the mounting space and the problem of the process simplification leading to improvement in productivity are simultaneously solved. .
[Brief description of the drawings]
FIG. 1 is a perspective view of an antenna according to the present invention.
FIG. 2 is a perspective view showing an example in which the antenna of the present invention is mounted on a personal computer as an information terminal device.
[Explanation of symbols]
1 antenna 2 antenna element (radiation electrode)
3 ground electrode 4 short-circuit member 5 conductive member 6 high-frequency coaxial cable S1 internal conductor impedance matching point S2 external conductor impedance matching point (earth point)

Claims (4)

An antenna, wherein an antenna element is opposed to a ground electrode via a short-circuit member, and a separate conductive member for increasing the area is attached to the ground electrode. The antenna according to claim 1, wherein the conductive member has flexibility. The antenna according to claim 1, wherein an area of the conductive member is 100% to 600% of an area of the ground electrode. The antenna according to any one of claims 1 to 3, wherein the conductive member is a conductive tape made of copper or aluminum.

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