JP2001217638A - Card type radio antenna - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the size of an antenna while improving the antenna gain. SOLUTION: Two plate-shaped loop antennas 14 and 16 are provided.
Are arranged adjacent to each other, and the second end portion 14 of the plate-shaped loop antenna 14 is
b and the third end portions 16a of the plate-shaped loop antenna 16 are connected to each other via a capacitive reactance 20 to form a single antenna having a double loop. Conductor part 14
c, 14d, 16c, 16d in coin button battery 26
The structure has a bulge toward the rear so as not to cover.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for a card-type wireless device connected to an information processing apparatus.

[0002]

2. Description of the Related Art FIG.
And what is shown in FIG. 5 is known. The card-type wireless device 12 is loaded into the information processing device 10,
A tip portion 12a made of metal or the like;
And a rear end 12b having a battery part and an antenna part. The antenna section is constituted by a single plate-shaped loop antenna 50 having a substantially rectangular parallelepiped shape.
0a is connected to the receiver input circuit 58 and the second end 50b
Is connected to a variable capacitive reactance 52. The variable capacitive reactance 52 is connected to the reference ground 60.

[0003] The battery section is composed of a coin-shaped button battery 54. The coin-shaped button battery 54 includes upper and lower conductors 50 c and 50 c of the plate-shaped loop antenna 50.
d.

[0004]

However, the above-mentioned prior art has the following problems. That is, considering the recent trend of the spread of small terminals such as PDA terminals, it is necessary to reduce the size of the rear end portion 12b of the card-type wireless device 12, but in the above-described conventional device, the antenna gain is a plate-like loop antenna. The size of the loop area is proportional to the size of the loop area 50, and the coin-shaped button battery 54 is disposed at a position over the conductors 50c and 50d of the plate-shaped loop antenna 50, thereby obstructing the magnetic field of the antenna and reducing the antenna gain. Therefore, in order to improve the antenna gain, it is necessary to considerably increase the loop area. For this reason, the rear end portion 12b becomes large in size with the improvement of the antenna gain, and greatly protrudes out of the information processing device 10.

[0005] The present invention has been made to solve such a problem, and an object of the present invention is to provide a card-type radio which can reduce the size of an antenna while improving the antenna gain.

[0006]

In order to solve the above-mentioned problems, the present invention relates to a card-type radio used as a radio modem by being connected to an information processing apparatus.
The card-type wireless device includes a front end portion loaded into the information processing device, and a rear end portion protruding outside the information processing device and having a battery unit and an antenna unit.
Two plate-like loop antennas are arranged adjacent to each other, and one end of each is connected to each other via a capacitive reactance.

As described above, two plate-shaped loop antennas are arranged adjacent to each other, and one end thereof is connected to each other via a capacitive reactance to form one antenna having a double loop structure. Since the gain is improved and the gain does not deteriorate even in a small area, the antenna can be downsized while improving the antenna gain. Therefore, the rear end of the card-type wireless device can be downsized.

Further, in the present invention, the two plate-like loop antennas are characterized in that these conductor portions have a bulge rearward so as not to cover the battery portion.

As described above, since the magnetic field of the antenna is not obstructed by expanding the conductor of the plate-shaped loop antenna rearward so as not to cover the battery, the antenna gain is not reduced.

[0010]

FIG. 1 is a plan view showing the internal structure of a card type radio 12 embodying the present invention, FIG. 2 is a perspective view showing an antenna unit and a battery unit, and FIG.
2 is a perspective view showing a state in which the information processing apparatus 2 is loaded into the information processing apparatus 10, and FIG. 4 is a graph showing antenna gains of the antenna section of the present invention and the conventional antenna section. Note that members described in the related art will be described using the same reference numerals.

[0011] The card-type wireless device 12 is provided with the information processing device 10.
A tip portion 12a that is loaded into the inside and is made of metal or the like;
A rear end portion 12b that protrudes outside the information processing device 10 and has a battery unit and an antenna unit. The antenna unit is configured by two plate-shaped loop antennas 14 and 16 that bulge rearward. One plate-shaped loop antenna 14 has a first end 14a and a second end 14a.
b to the other plate-like loop antenna 16
Has two ends, a third end 16a and a fourth end 16b, respectively, and the first end 14a is connected to the receiver input circuit 18. The second end 14b and the third end 16a are connected to each other via a capacitive reactance 20, and the fourth end 16b is connected to the variable capacitive reactance 2
2 are connected. The variable capacitive reactance 22 is
The resonance of the two plate-shaped loop antennas 14 and 16 at the reception frequency is matched, and the variable capacitive reactance 22 is connected to the reference ground 24.

The battery section is constituted by a coin-shaped button battery 26. The upper and lower antenna conductors 14c and 14d bulging rearward of one of the plate-shaped loop antennas 14 do not cover the coin-shaped button battery 26, The upper and lower antenna conductors 16 c and 16 d swelling rearward of the other plate-shaped loop antenna 16 have a structure in contact with the end face of the coin-shaped button battery 26.

Next, the operation of the card type radio antenna according to the embodiment of the present invention will be described. By connecting the second end portion 14b and the third end portion 16a of the two plate-shaped loop antennas 14 and 16 to each other via the capacitive reactance 20, the two plate-shaped loop antennas are connected to one having a double loop structure. Since the antenna can be used, the antenna gain is improved and the gain does not deteriorate even in a small area.

Further, by connecting the variable capacitive reactance 22 to the fourth end 16b, the two plate-shaped loop antennas 14 and 16 can be operated by resonating at the reception frequency. Furthermore, two plate-like loop antennas 1
4 and 16 antenna conductors 14c, 14d, 16c,
Since 16d does not cover the coin-shaped button battery 26, the magnetic field of the antenna is not hindered and the antenna gain does not decrease.

Therefore, as shown in FIG. 4, the directional characteristics of the antenna on the XY plane in the case of the vertically polarized wave are the same as those of the planar loop antennas 14 and 16 of the present invention. A result is obtained which is superior to the directivity 30 of the conventional plate-shaped loop antenna 50 having a larger loop area.

[0016]

As described above, the present invention has a double loop structure by arranging two plate-like loop antennas adjacent to each other and connecting their one ends to each other via a capacitive reactance. Since one antenna can be used, the antenna gain is improved, and the gain is not deteriorated even in a small area. Therefore, the antenna can be downsized while improving the antenna gain. Therefore, the rear end of the card-type wireless device can be downsized.

Further, according to the present invention, the magnetic field of the antenna is not obstructed by expanding the conductor of the plate-shaped loop antenna rearward so as not to cover the battery, so that the antenna gain is not reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an antenna unit and a battery unit of the present invention.

FIG. 2 is a plan view showing the internal structure of a card-type wireless device embodying the present invention.

FIG. 3 is a perspective view showing a state where a card-type wireless device is loaded in an information processing apparatus.

FIG. 4 is a graph showing antenna gains of the antenna unit of the present invention and a conventional antenna unit.

FIG. 5 is a perspective view of a conventional antenna unit.

[Explanation of symbols]

 14, 16 plate-shaped loop antenna 14b second end 16a third end 14c, 14d, 16c, 16d conductor 20 capacitive reactance 26 coin-shaped button battery

Claims (2)

[Claims] 1. A card-type wireless device which is used as a wireless modem by being connected to an information processing device, wherein the card-type wireless device has a tip mounted in the information processing device, Projecting, a battery unit and a rear end having an antenna unit, wherein the antenna unit is
An antenna for a card-type wireless device, wherein two plate-shaped loop antennas are arranged adjacent to each other, and one ends thereof are connected to each other via a capacitive reactance. 2. The card-type radio device according to claim 1, wherein the two plate-shaped loop antennas have a bulge rearward so that these conductor portions do not cover the battery portion. antenna.