JP2002314316A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna system in which the dimension of a board on which a chip antenna is mounted can be smaller than in the conventional practice, making a communication device accordingly smaller. SOLUTION: The chip antenna 12 is mounted on the board 10 in such a manner that the part of a feed terminal 26 of an antenna conductor 22 is overlapped on a ground pattern 18 and a part closer to the tip than the part is not overlapped on the ground pattern 18. The chip antenna 12 has a meandering antenna conductor 22 where a meandering pitch on the feed terminal 16 is close and a meandering pitch on the tip side is rougher, and is mounted so that the part 22a where the meandering pitch of the antenna conductor 22 is closer can be partially or entirely overlapped on the ground pattern 18. The dimensions A of an area without the ground pattern 18 can be small. Matching can be conducted by adjusting overlapped dimension B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device used for a small communication device such as a portable telephone.

[0002]

2. Description of the Related Art It is known to use an antenna device in which a surface-mounted chip antenna is mounted on a printed circuit board in order to reduce the size of a portable telephone or the like. FIG. 13 shows an example of this type of conventional antenna device. In the figure, 10 is a printed circuit board, 12 is a printed circuit board
The chip antenna mounted on 10, and 14 is a coaxial feed line.

The printed circuit board 10 has a ground pattern 18 made of copper foil or the like provided on one surface of an insulating substrate 16 and a circuit conductor pattern (not shown) provided on the opposite surface. The printed circuit board 10 has a chip antenna 12
Is provided, a region without the ground pattern 18 is provided.

[0004] The chip antenna 12 has an antenna conductor 22 provided on the surface or inside of a dielectric chip 20. Although the illustrated antenna conductor 22 has a meandering shape, the antenna conductor may have a helical shape or another pattern.
The chip antenna 12 is mounted on the printed circuit board 10 in a region where the ground pattern 18 is not provided. The center conductor 24 of the coaxial feed line 14 is connected to the feed terminal 26 of the chip antenna 12 by an external conductor.
Reference numeral 28 is connected to the ground pattern 18 by soldering or the like. A strip line may be used instead of the coaxial feed line 14.

[0005]

As described above, in the conventional antenna device, the chip antenna 12 is mounted in an area of the printed circuit board 10 where the ground pattern 18 is not provided. This is to prevent the characteristics of the chip antenna from being affected by the ground pattern. However, in such a configuration, since the dimension A of the area of the printed circuit board 10 where the ground pattern 18 is not provided is determined by the dimension of the chip antenna 12, it is difficult to reduce the dimension of the printed circuit board by a certain degree or more. Was.

In view of the above problems, an object of the present invention is to provide an antenna device which can reduce the size of a substrate on which a chip antenna is mounted, as compared with the related art, and thus can further downsize a communication device. is there.

[0007]

Means for Solving the Problems In order to achieve this object, the present invention provides an antenna device in which a chip antenna is mounted on a substrate having a ground pattern. The semiconductor device is characterized in that it is mounted on a substrate so that it overlaps with the ground pattern and a portion on the tip side thereof does not overlap with the ground pattern. With such a configuration, the size of the substrate can be reduced as much as the chip antenna sinks on the ground pattern side, and it becomes easy to match the chip antenna with the feed line.

As the chip antenna, an antenna provided with a meandering antenna conductor or a helical antenna conductor on the surface or inside of a dielectric chip can be used. The meander and helical pitches of these antenna conductors may be uniform, or there may be rough portions and dense portions.

When the antenna conductor of the chip antenna has a meandering shape, the meandering pitch of the antenna conductor is made denser on the feeder terminal side and coarser on the tip side, and a part of the meandering pitch of the meandering antenna conductor is denser. Alternatively, it is preferable that the semiconductor device is mounted on the substrate such that the entirety overlaps the ground pattern. When the antenna conductor of the chip antenna is helical, the helical pitch of the antenna conductor is made dense on the feeder terminal side and coarse on the tip side, and part or all of the helical pitch of the helical antenna conductor is dense. Is preferably mounted on the board so that the pattern overlaps the ground pattern. With such a configuration, adjustment for achieving alignment becomes easier.

The substrate on which the chip antenna is mounted is
It has a pad for fixing the tip of the chip antenna at a position distant from the edge of the ground pattern, and this pad is formed so as not to protrude from the tip of the chip antenna. It is preferable in terms of conversion.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 shows an embodiment of the present invention. The antenna device includes a printed circuit board 10 having a ground pattern 18 on one surface of an insulating substrate 16 and a meandering antenna conductor 22 on the surface or inside a dielectric chip 20.
A chip antenna 12 having the following is mounted. The meandering antenna conductor 22 of the chip antenna 12 is
The meandering pitch is formed to be dense on the 26 side and coarse on the tip side. Dense part 22a of meandering pitch
Each of the rough portions 22b having a meandering pitch is formed such that the meandering is repeated a plurality of times. Chip antenna
12 is mounted such that a part or the whole of the dense portion 22a of the meandering pitch overlaps with the ground pattern 18, and a portion on the tip side thereof projects from the edge of the ground pattern 18.

With this mounting method, it is possible to easily match the chip antenna 12 with the coaxial feed line 14 by adjusting the dimension B at which the chip antenna 12 overlaps the ground pattern 18. , VSWR
(Voltage standing wave ratio) can be reduced. In the conventional mounting method, in order to lower the VSWR, it is necessary to devise the shape of the antenna conductor, the position of the power supply terminal, and the like.
If it is designed to lower the bandwidth, there has been a problem that the bandwidth becomes narrower.

In the antenna device of FIG. 2, the width of the dielectric chip 20 in the antenna device of FIG.
22 is made smaller than the meandering width of the antenna conductor 22, the middle part of the antenna conductor 22 in the meandering width direction is embedded in the dielectric chip 20, and both sides are bent along the surface of the dielectric chip 20 to reduce the size. It is.

FIG. 5 shows the results of measurement of the relationship between the overlap dimension B and the VSWR, and FIG. 6 shows the results of the measurement of the relationship between the overlap size B and the bandwidth in the antenna device as shown in FIG. The size of the printed circuit board 10 used is 33 mm wide x 150 mm long
(The size of the insulating substrate 16), the size of the ground pattern 18 is 33mm wide x 120mm long, and the size of the fixed pad 32 is 2mm wide.
X length 1mm, chip antenna 12 is 4.2mm wide x 1 length
The meandering pitch of the meandering antenna conductor 22 is 6 mm x 1.1 mm, and the dense portion 22a of the meandering pitch 22a has a line / line width of 150/150 μm for 27 turns, and the coarse portion 22b of the meandering pitch has a line / line width of 200/200. 200
There are 17 turns in μm. The meandering width of the meandering antenna conductor before bending was 8.7 mm. 5 and 6, when the overlapping dimension B is negative, the ground pattern 18 and the chip antenna 12 are separated as shown in FIG. 13, and when the overlapping dimension B is positive, the ground pattern 18 and the chip antenna 12 are overlapped as shown in FIG. . The measurement was performed by connecting the coaxial feed line 14 to a network analyzer. The resonance frequency is 10 when B = 3 mm
33 MHz.

As is clear from FIGS. 5 and 6, when the mounting structure of the present invention is adopted, the VSWR can be adjusted by adjusting the mounting position (dimension B) of the chip antenna 12, so that the VSWR can be easily adjusted. In addition, there is an effect that the bandwidth is widened at a low VSWR. That is, there is an advantage that matching can be easily performed. Conventionally VS
Although the bandwidth was narrowed when the WR was lowered, this point has been greatly improved. In this embodiment, since the side of the portion 22a where the meandering pitch is dense overlaps with the ground pattern 18, the above-mentioned effect is particularly remarkable. Also, the printed circuit board 10 is a ground pattern required for antenna mounting.
The dimension A of the area without 18 can be made smaller than before, which is effective for miniaturization of communication equipment.

The chip antenna 12 is a dielectric chip
By soldering the fixed pad portions 30A and 30B formed on the bottom surface of the ground 20 to the ground pattern 18 and the pad 32 formed at a position away from the edge of the ground pattern 18,
Although mounted on the printed circuit board 10, if the pads 32 are formed so as not to protrude from the tip of the chip antenna 12, the dimension A of the area of the printed circuit board 10 where the ground pattern 18 is not provided can be further reduced. it can.

Embodiment 2 FIG. 3 shows another embodiment of the present invention. This antenna device is one in which the meandering pitch of the antenna conductor 22 in the antenna device as shown in FIG. 2 is constant. The other parts are the same as those of the antenna device of FIG. 2, and the same parts as those of FIG. 2 are denoted by the same reference numerals.

FIG. 7 shows the results of measurement of the relationship between the overlap dimension B and the VSWR, and FIG. 8 shows the results of the measurement of the relationship between the overlap size B and the bandwidth in the antenna device of FIG. The size of the used printed circuit board 10 is 33 mm in width and 150 mm in length (size of the insulating substrate 16), and the size of the ground pattern 18 is 33 in width.
mm x length 120mm, fixed pad 32 is 2mm wide x 1mm long, chip antenna 12 is 4.3mm wide x 16.0mm long
The thickness of the meandering antenna conductor 22 is 1.2 mm, the meandering pitch of the line / line width is 200/180 μm, and 37 turns. The meandering width of the meandering antenna conductor 22 before bending was 8.9 mm. The resonance frequency was 952 MHz when B = 3 mm.

FIGS. 7 and 8 show that the VSWR can be easily adjusted similarly to the first embodiment, and that the bandwidth is widened where the VSWR is low.

Embodiment 3 FIG. 4 shows another embodiment of the present invention. In this antenna device, the size of the fixed pad 32 in the antenna device of FIG.
Is projected by 2 mm. The other parts are the same as those of the antenna device of FIG. 3, and the same parts as those of FIG. 3 are denoted by the same reference numerals.

FIG. 9 shows the results of measurement of the relationship between the overlap dimension B and the VSWR, and FIG. 10 shows the results of the measurement of the relationship between the overlap size B and the bandwidth in the antenna device of FIG. The resonance frequency was 874 MHz when B = 3 mm.

FIGS. 9 and 10 show that the VSWR can be easily adjusted as in the first embodiment, and that the bandwidth is widened at a low VSWR.

Embodiment 4 FIG. 11 shows another embodiment of the present invention. This antenna device is a printed circuit board
A strip line 34 is formed as a feed line on 10, a feed terminal 26 is formed on the lower surface side of the dielectric chip 20 of the chip antenna 12, and the feed terminal 26 of the chip antenna 12 is connected to the strip line 34 by soldering or the like. It was done.
Even with such a configuration, the same effect as in the first embodiment can be obtained. Since the configuration other than the above is the same as that of the embodiment of FIG. 1, the same portions are denoted by the same reference numerals and description thereof will be omitted.

Embodiment 5 FIG. 12 shows still another embodiment of the present invention. This antenna device has an insulating substrate 16
The power supply strip line 34 is formed on the surface on which the chip antenna 12 is mounted, and the ground pattern 18 is provided on the opposite surface. The other configuration is the same as that of the embodiment of FIG. 11, and therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted.

[Other Embodiments] In the above embodiments, the case where the meandering pitch of the meandering antenna conductor of the chip antenna is made uniform, and the case where the meandering pitch is made dense on the feeder terminal side and roughened on the tip end side are described. However, the chip antenna coarsely adjusts the meandering pitch of the meandering antenna conductor on the feed terminal side,
It may be dense on the tip side. In the above embodiments, the case where the antenna conductor of the chip antenna has a meander shape has been described. However, the present invention is similarly applicable to the case where the antenna conductor of the chip antenna has a helical shape.

[0027]

According to the present invention as described above,
By mounting the chip antenna on the substrate such that the antenna conductor on the power supply terminal side of the chip antenna overlaps the ground pattern, it is possible to reduce the size of the area of the substrate without the ground pattern, and thus reduce the size of the communication device. be able to. In addition, when the power supply terminal side of the chip antenna is overlapped with the ground pattern, matching between the chip antenna and the power supply line can be achieved by adjusting the overlapping dimension, thereby facilitating the design and manufacture of the antenna.

[Brief description of the drawings]

1A and 1B show an embodiment of an antenna device according to the present invention, wherein FIG. 1A is a front view and FIG. 1B is a side view.

FIG. 2 shows an example of an antenna device of the type shown in FIG. 1 in which the width of a dielectric chip is smaller than the meandering width of a meandering antenna conductor, (A) is a front view, and (B) is a side view.

3A and 3B show another embodiment of the antenna device according to the present invention, wherein FIG. 3A is a front view and FIG. 3B is a side view.

4A and 4B show still another embodiment of the antenna device according to the present invention, wherein FIG. 4A is a front view and FIG.

FIG. 5 is a graph showing a change in VSWR when the overlapping dimension B of the antenna conductor and the ground pattern is changed in the antenna device of FIG. 2;

FIG. 6 is a graph showing a change in bandwidth when the overlap dimension B is changed.

FIG. 7 is a graph showing a change in VSWR when the overlapping dimension B between the antenna conductor and the ground pattern is changed in the antenna device of FIG. 3;

FIG. 8 is a graph showing a change in bandwidth when the overlap dimension B is changed.

9 is a graph showing a change in VSWR when the overlapping dimension B of the antenna conductor and the ground pattern is changed in the antenna device of FIG. 4;

FIG. 10 is a graph showing a change in bandwidth when the overlap dimension B is changed.

11 (A) is a front view and FIG. 11 (B) is a cross-sectional view showing still another embodiment of the antenna device according to the present invention.

FIG. 12 (A) shows still another embodiment.
Is a front view, and (B) is a side view.

FIG. 13A shows an example of a conventional antenna device.
Is a front view, and (B) is a side view.

[Explanation of symbols]

10: Printed circuit board 12: Chip antenna 14: Coaxial feed line 16: Insulating substrate 18: Ground pattern 20: Dielectric chip 22: Meander-shaped antenna conductor 22a: Part with a meandering pitch 22b: Part with a meandering pitch 32 : Pad 34: Strip line A: Dimension of area of printed circuit board 10 without ground pattern 18 B: Overlap dimension of chip antenna 12 and ground pattern 18

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Isawa 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Toshiyuki Imagawa 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo No. Within Sony Corporation (72) Inventor Minoru Ozeki 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term within Sony Corporation (reference) 5J046 AA03 AA07 AB06 AB12 AB13 PA04 PA07 5J047 AA03 AA07 AB06 AB12 AB13 FD01

Claims (4)

[Claims] 1. An antenna device comprising a chip antenna (12) mounted on a substrate (10) having a ground pattern (18), wherein the chip antenna (12) is connected to a feed terminal (26) of an antenna conductor (22). The antenna device is mounted so that a portion on the side overlaps the ground pattern (18) and a portion on the distal end side does not overlap with the ground pattern (18). 2. The antenna device according to claim 1, wherein the chip antenna (12) has a meandering or helical antenna conductor (22). 3. The chip antenna (12) is connected to a power supply terminal (2).
6) A meandering antenna conductor (22) having a meandering pitch on the side and a coarse meandering pitch on the tip side has a meandering pitch of the meandering antenna conductor (22).
The antenna device according to claim 1, wherein a part or all of a) is mounted so as to overlap with the ground pattern (18). 4. The substrate (10) includes a ground pattern (18).
A pad (32) for fixing the tip of the chip antenna (12) at a position away from the edge of the pad (32).
4. The antenna device according to claim 1, wherein the antenna device is formed so as not to protrude from the tip of the chip antenna (20).