This application claims priority from Japanese Priority Document No. 2003-152443, filed on May 29, 2003 with the Japanese Patent Office, which document is hereby incorporated by reference.
1. Field of the Invention
This invention relates to an antenna element mounting method and a surface mount antenna, and more particularly to a surface mount antenna designed to standardize an antenna element to be mounted on a set, and an antenna element mounting method.
2. Description of the Related Art
A surface mount antenna of a conventional technology is such that an antenna has an antenna element formed with electrodes on surfaces of dielectric material or magnetic material. The antenna of this type is designed to perform an impedance matching at a feed section by itself, and to match with a predetermined utilized frequency. For example, see Japanese Laid-Open Patent No. PH10-173434.
However, in the conventional antenna such as described above, the antenna element is adapted to use by mounting on a mount board when this antenna element is assembled in a set. When this antenna element is assembled in a different set, a mount board is also different usually, and a ground GND is also different, so that an impedance matching and a receiving utilized frequency of the antenna element are misaligned when the antenna element is assembled as it is. On this account, the conventional antenna element where the electrodes are formed on the dielectric material or the magnetic material is to be different as per set. Accordingly, in standardizing the mount parts, there is a problem that the antenna element itself is not able to be standardized without drastic improvements.
Accordingly, in an antenna element mounting method and a surface mount antenna realizing the use of standard antenna element even in the different set, there is a problem to be solved.
In order to solve the above-mentioned problem, the surface mount antenna and the antenna element mounting method are based on the following configuration. That is, a surface mount antenna is the antenna to be configured by mounting on a mount board an antenna element by forming electrodes on a dielectric material, and the electrodes are formed to have a ground electrode and a feed electrode, wherein both ends of the ground electrode and the feed electrode are directed in an opposed relation to each other, and a ground mount pattern to be connected to the ground electrode and a feed mount pattern to be connected to the feed electrode are formed to have a predetermined distance between them on the mount board. In the above mentioned surface mount antenna, the feed mount pattern is provided on a backside of the board. Further, in the above mentioned surface mount antenna, the dielectric material is formed to be a rectangular solid shape, and the electrodes are formed to include a right bottom face of the feed electrode, a right side face, a top face, a left side face, and left bottom face of the ground electrode so as to cover surfaces of the rectangular solid shaped dielectric material by the electrodes.
In the antenna element mounting method according to the present invention, when an antenna element formed by forming electrodes on surfaces of a dielectric material is mounted on a board, an utilized frequency is adjusted by changing an impedance by varying a pattern width of a portion connecting a ground electrode of the above mentioned electrodes and a GND pattern of a ground side of the board, and an impedance matching is performed by changing a capacitance based on a dielectric constant of the board by varying an area of a surface of a feed pattern at a position of a feed side of the board in opposing relation to a feed electrode of the above mentioned electrodes. In the above mentioned antenna element mounting method, the feed pattern is provided on a backside of the board. In the above mentioned antenna element mounting method, the dielectric material is formed to be a rectangular solid shape, and the electrodes are formed to include a right bottom face of the feed electrode, a right side face, a top face, a left side face, and left bottom face of the ground electrode so as to cover surfaces of the rectangular solid shaped dielectric material by the electrodes.
According to the present invention as described above, an utilized frequency is adjusted by changing an impedance by varying a pattern width of a portion connecting a ground electrode of the above mentioned electrodes and a GND. pattern of a ground side of the board, and an impedance matching is performed by changing a capacitance based on a dielectric constant of the board by varying area of a surface of a feed pattern at a position of a feed side of the board in opposing relation to a feed electrode of the above mentioned electrodes while the shapes of the dielectric material and the electrodes configuring the antenna element are left unchanged. Therefore, it becomes possible to adjust a predetermined utilized frequency and to perform an impedance matching by changing the GND pattern side and the feed pattern side without changing the shape of the antenna element. This means that it is possible to standardize the antenna element by using the common antenna element, even though the board side of the set may have a change or an external factor.
In the accompanying drawings:
Now, embodiments of a surface mount antenna and an antenna element mounting method according to the present invention are described with reference to the accompanying drawings. In a surface mount antenna capable of specifying the antenna element mounting method of the present invention, an antenna element 12 is mounted on a part of a surface of a board 11 as shown in
The antenna element 12 is formed as to cover surfaces of a dielectric material 13 formed with a rectangular solid shaped ceramics or the like by a metal electrode 14 as shown in
In the electrode 14, both ends of a rectangular shaped plate-like metal member are bent so as to be opposed to each other, and are formed to have a predetermined distance between them, thereby the electrode 14 is so configured that one of the ends becomes the ground electrode 15 to be connected to the ground side, and the other end becomes the feed electrode 16 to be connected to the feed side. In this embodiment, the electrode 14 has a shape consistent with the shape of the rectangular solid shaped dielectric material 13, and comprises of a top face 17 made from a rectangular shaped plate-like metal member having a width of the dielectric material 13 for covering the top face 17 of the rectangular solid shaped dielectric material 13, a right side face 18 formed by folding one edge of the plate-like metal member perpendicularly to the top face 17 for covering a right side face of the dielectric material 13, a left side face 19 formed by folding the other edge of the plate-like metal member perpendicularly to the top face 17 for covering a left side face of the dielectric material 13, the feed electrode 16 to be a right bottom face by folding inside the plate-like metal member perpendicularly to the right side face 18 for covering a part of bottom face of the dielectric material 13, and the ground electrode 15 to be a left bottom face by folding inside the plate-like metal member perpendicularly to the left side face 19 for covering a part of bottom face of the dielectric material 13. This electrode 14 is a symmetrical shape, and when this electrode 14 is mounted on the board 11, it is possible to mount this electrode 14 with disregard to a direction of thereof. Depending on how to assemble, the left side. becomes the ground electrode 15 of the ground side and the right side becomes the feed electrode 16 of the feed side in
As a shape of such electrode 14, there are various shapes to be employed. That is, the shape only requires to be such a shape matching with the shape of the dielectric material 13 and being able to be mounted on the board 11, and they may be one where a ground electrode and a feed electrode are folded outside as shown in
Further, the shape of the electrode 14 is not limited to a rectangular shape when viewed from above. For example, the top face of the electrode 14 may be a trapezoidal shape as shown in
In the present embodiment, the antenna element 12 has a rectangular. solid shape, and this the antenna element 12 is mounted on the board 11 as shown in
In the ground side, a mounting processing of the antenna element 12 on the board 11 is carried out by providing the ground mount pattern 22 at a surface side of the board 11 to which the antenna element 12 is mounted, and by connecting the ground mount pattern 22 to the GND pattern 21 by way of the ground pattern 25 having a certain pattern width L as shown in
The ground pattern 25 is for adjusting the inductance, so the shape of the ground pattern 25 is thought to have various shapes without limiting to the rectangular shape. For example, the shape of the ground pattern 25 may be a rectangular shape same as the present embodiment as shown in
In the feed side, the feed mount pattern 23 is provided on the surface side of the board 11 to which the antenna element 12 is mounted as shown in
In this case, the feed mount pattern 23 and the feed pattern 24 of the feed side may not always be perfectly opposed to each other at both sides of the board 11, because it is enough to obtain a desired capacitance. For example, the desired capacitance may be obtained by adjusting the dislocation of the feed pattern 24 relative to the feed mount pattern 23 as shown in
Now, a method for adjusting the utilized frequency and the impedance matching is described here with reference to
When the frequency is lowered from “A” to “B” in
Next, in case of carrying out the impedance matching, by changing an area of the face in the feed pattern 24 (
There is a case where the frequency is displaced a bit as the capacitance changes, but the displacement in frequency is within an allowable range. If the frequency is changed largely, it is possible to make close to a target frequency by alternately carrying out the above-mentioned frequency adjustment and the impedance matching.
Conventionally, if the antenna element 12 was mounted on respective set, it was necessary to carry out the adjustment of frequency and the impedance matching as per respective set due to the difference in the state of the GND and the radiation load by a cabinet around the antenna element 12 as per set. Accordingly, in each of the conventional mount antenna, it was necessary to adjust the frequency by changing the length of the electrode and to carry out the impedance matching by providing radiation electrode to the antenna element.
According to the present invention, the board 11 for mounting the antenna element 12 is manufactured as per respective set, so it is possible to use the standardized antenna element 12, and to determine the utilized frequency by designing the pattern width (ground pattern 25) between the ground mount pattern 22 and the GND pattern 21 of the ground side on the mount board. Further, it is possible to perform the impedance matching by designing the size of the feed mount pattern 23 and the feed pattern 24 of the feed side. Thus, according to the present invention, it is possible to perform the adjustment of frequency and the impedance matching with the board pattern of respective set by using one type of the antenna element 12, so it becomes possible to standardize the antenna element where the adjustment becomes easy and the antenna element 12 is able to mount a different set as an assembling part.
Number | Date | Country | Kind |
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P2003-152443 | May 2003 | JP | national |