JPH0522017A - Multiple loop antenna - Google Patents

Abstract

PURPOSE:To reduce the area of a loop antenna occupying a printed wiring board by obtaining a desired antenna gain by overlapping plural loop-shaped antennas having a small opening area. CONSTITUTION:On the respective first-third layers of a multilayered printed wiring board 1, loop-shaped patterns 3a-3c are formed in the state overlapped in the thicknesswise direction of the multilayered printed wiring board 1. For these loop-shaped patterns 3a-3c, one terminal side of the pattern 3a is connected to a circuit pattern 5, the other terminal side of the pattern 3a is connected through a through hole 7a to one terminal side of the pattern 3b, the other terminal side of the pattern 3b is connected through a through hole 7b to one terminal side of the pattern 3c, the other terminal side of the pattern 3c is connected through a through hole 7c to a ground pattern 9, and the triple loop antenna is formed. Therefore, the area occupied on the multilayered printed wiring board 1 can be reduced, and the desired antenna gain can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loop antenna using a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, when a loop antenna is provided on a printed wiring board, a loop-shaped metal rod is erected on the printed wiring board and the loop antenna is formed by the metal rod and the pattern of the printed wiring board. However, with this method, the thickness of the entire printed wiring board unit is increased due to the metal rod, which makes it difficult to reduce the thickness of the device.

In order to solve this problem, when a loop pattern is provided on the printed wiring board to form a loop antenna, a loop pattern having a large opening area is formed on the printed wiring board in order to obtain a predetermined antenna gain. There is a need to. In this case, mounting an electronic component inside the loop-shaped pattern adversely affects the antenna effective value.Therefore, it is necessary to mount the electronic component in an area outside the loop-shaped pattern, and the area of the loop antenna occupying the printed wiring board is reduced. There was the problem of getting too big.

[0004]

As described above, when the metal rod is erected and the loop antenna is formed on the printed wiring board, the thickness of the printed wiring board unit becomes large, so that the equipment can be made thin. However, when the loop pattern having a large opening area is formed on the printed wiring board to form a loop antenna, the area of the loop antenna occupying the printed wiring board becomes too large.

The present invention has been made in order to solve the conventional drawbacks described above, and can be formed by utilizing the pattern of a printed wiring board, and further, the multiple loop which can occupy a small area on the printed wiring board. The purpose is to provide an antenna.

[0006]

A multiple loop antenna of the present invention has a plurality of loop-shaped patterns formed on different layers of a multilayer printed wiring board and a plurality of loop-shaped patterns formed on the multilayer printed wiring board. And a through hole that connects the patterns in series.

[0007]

In the present invention, since loop patterns formed on different layers of a multilayer printed wiring board are connected by through holes to form a multiple loop antenna, even if the opening area of the loop pattern is small. A predetermined antenna gain can be obtained by superposing a plurality of loop-shaped patterns.

[0008]

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

FIGS. 1 and 2 are views for explaining the first embodiment. FIG. 1 is an exploded perspective view of a multilayer printed wiring board having a multiple loop antenna according to the present invention, and FIG. It is a schematic diagram of a multiple loop antenna.

The multi-loop antenna according to the present invention is shown in FIG.
As shown in FIG. 3, it is formed using the pattern of the multilayer printed wiring board 1. That is, each of the one-layer, two-layer, and three-layer of the multilayer printed wiring board 1 has a loop-shaped pattern 3a in a state of overlapping in the thickness direction of the multilayer printed wiring board 1.
3b and 3c are formed. These loop-shaped patterns 3a, 3b, 3c have one end of the pattern 3a connected to the circuit pattern 5, and the other end of the pattern 3a connected to one end of the pattern 3b through a through hole 7a.
The other end of the pattern 3b is connected to one end of the pattern 3c through a through hole 7b, and the other end of the pattern 3c is connected to an earth pattern 9 through a through hole 7c, as shown in FIG. A triple loop antenna 11 is formed.

In this way, the loop antenna 11 of this example is
By making the loop-shaped patterns 3a, 3b, 3c each have a small opening area, the area occupied in the multilayer printed wiring board 1 can be reduced and a desired antenna gain can be obtained. .

3 and 4 are diagrams for explaining a second embodiment of the present invention.

The multi-loop antenna 11a of this embodiment is also similar to the first embodiment in that it is formed by three types of loop-shaped patterns 3a, 3b, 3c formed on the multilayer printed wiring board 1a. . However, in this example, the patterns 3a, 3b and 3c are the chip type capacitors 1
They are connected in series with 3a and 13b interposed.
Therefore, the C component can be interposed in the middle of the loop antenna, and the fine adjustment of the antenna sensitivity can be easily performed appropriately by changing the connection of the capacitor.

[0014]

As described above, in the multiple loop antenna of the present invention, a desired antenna gain is obtained by superimposing a plurality of loop patterns having a small aperture area.
The area of the loop antenna that occupies the printed wiring board can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a multilayer printed wiring board having a multiple loop antenna according to a first embodiment of the present invention.

FIG. 2 is a schematic explanatory view of the multiple loop antenna of FIG.

FIG. 3 is a plan view of a multiple loop antenna according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram of the multiple loop antenna of FIG.

[Explanation of symbols]

 1, 1a ... Multilayer printed wiring board 3a, 3b, 3c ... Loop pattern 7a, 7b ... Through hole 11 ... Multiple loop antenna

Claims (1)

Claim: What is claimed is: 1. A plurality of loop-shaped patterns formed on different layers of a multilayer printed wiring board and the plurality of loop-shaped patterns formed on the multilayer printed wiring board are connected in series. A multiple loop antenna comprising a through hole.