JPH10209744A - Inverted f-type antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust a resonance frequency by relatively varying the depth or circumferential length of a slit by removing part of a metal conductor at the outside side, facing the bottom part or side part of a slit formed in the metal conductor so as to an inverted F-type antenna of portable small-sized communication equipment. SOLUTION: Two rectangular slits 4 are formed, so that the dielectric 3 of the center part of a metal conductor 2 is exposed from mutually different directions from the opposite external sides of the metal conductor 2 formed on a plate-type substrate of the dielectric 3. At a part facing the end part having a feed point 6 and a short-circuit point 5, a 1st removal part 9 of the metal conductor 2 facing the bottom part is removed by a fixed width from the external side to lower a resonance frequency at a certain rate. Further, a 2nd removal part 10 of the external side facing the side part 8 of the slit 4 is removed by a certain width in parallel to the external side for increasing the resonance frequency at a specific rate. Consequently, the resonance frequency can be adjusted easily, even after the metal conductor has been formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small antenna mounted on a small communication device such as a portable radio communication device, and more particularly to an inverted-F antenna capable of easily adjusting a resonance frequency. It is.

[0002]

2. Description of the Related Art In recent years, communication devices using frequencies in a microwave band, a quasi-microwave band, and the like have been put into practical use, and small antennas have been widely used. In particular, portable wireless communication devices have become very popular, and an inverted-F antenna as shown in FIG. 6 has been used to satisfy the demand for further reduction in size and weight.

The inverted F-type antenna 1 as described above has a feed point 6 and a short-circuit point 5 and is small and lightweight, but generally has a narrow band of frequency characteristics. It has characteristics determined by the dimensions, the dielectric constant of the dielectric 3, and the like.

As the dielectric 3, a printed wiring board is usually used, and the metal conductor 2 is manufactured by a manufacturing method for manufacturing a printed wiring board, or by molding the dielectric 3 into an antenna shape, It can be manufactured by bonding the conductor 2 or forming it by plating or the like.

The dielectric 3 constituting the inverted F-type antenna 1 has a variation in dielectric constant depending on a manufacturing lot, a variation in antenna thickness, and a variation in the metal conductor 2.
And the assembly frequency due to soldering when assembling the antenna, the resonance frequency changes for each individual antenna, so it is necessary to adjust the resonance frequency for each individual antenna. Adjustment of the resonance frequency was performed by removing.

[0006]

However, according to the above-described conventional method of adjusting the resonance frequency, the change in the resonance frequency obtained by the method of removing a part of the metal conductor is only a change in which the frequency becomes higher. Could not lower. In addition, in the method of removing a part of the metal conductor, it is necessary to remove the metal conductor while monitoring the change in the resonance frequency, which requires labor for the adjustment operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the resonance frequency easily by removing the metal conductor even after the metal conductor of the antenna is formed. It is an object of the present invention to provide an inverted-F antenna that can be adjusted by lowering it.

[0008]

According to a first aspect of the present invention, there is provided an inverted-F antenna having a metal conductor provided on a surface of a dielectric.
In the inverted-F type antenna having at least one slit 4 in the metal conductor 2, the resonance frequency of the antenna can be adjusted to be low by removing the outer metal conductor 2 facing the bottom 7 of the slit 4. It is characterized by.

An inverted F-type antenna according to a second aspect of the present invention comprises:
The inverted F-type antenna according to the first aspect is characterized in that the resonance frequency of the antenna can be adjusted to be high by removing the outer metal conductor 2 facing the side portion 8 of the slit 4.

[0010] The inverted F-type antenna according to the third aspect of the present invention comprises:
In the inverted F-type antenna according to the first and second aspects of the present invention, it is preferable that a mark 11 is provided at a fixed position from the outer side in the removed portions 9 and 10 of the metal conductor 2 removed to adjust the resonance frequency of the antenna. Inverted-F antenna.

An inverted F-type antenna according to a fourth aspect of the present invention comprises:
In the inverted F-type antenna according to the third aspect, the marks 11 formed on the removed portions 9 and 10 of the metal conductor 2 are formed by the minute slits 12 at positions opposing each other on two sides adjacent to the outer side. It is characterized by the following.

An inverted F-type antenna according to a fifth aspect of the present invention comprises:
The inverted F-shaped antenna according to the third and fourth aspects is characterized in that the minute slit 13 is formed as the mark 11 in parallel with the outer side and intermittently.

An inverted-F antenna according to the present invention is an inverted-F antenna in which a metal conductor 2 is provided on a surface of a plate-shaped dielectric 3 and the metal conductor 2 has at least one slit 4. The conductor 2 has a bent shape, and a feeding point 6 is provided at one end of the metal conductor 2 having the bent shape.
And a short-circuit point 5 are formed, and a ground conductor is formed on the back surface of the dielectric 3 on which the metal conductor 2 is formed.

The metal conductor 2 to be removed in order to lower the resonance frequency of the inverted-F type antenna has the feeding point 6 and the short-circuit point 5 formed on the outer side of the metal conductor 2 facing the bottom 7 of the slit 4. This is a portion facing one end of the metal conductor 2. By removing the first removing portion 9 with a constant width from the outer side, the resonance frequency can be reduced at a constant rate.

The metal conductor 2 to be removed in order to increase the resonance frequency of the inverted F-type antenna is provided in the slit 4
The outer periphery of the metal conductor 2 facing the side 8 of the
And the other end different from the one end of the metal conductor 2 where the short-circuit point 5 is formed. By removing the second removing portion 10 with a constant width from the outer side, the resonance frequency can be increased at a constant rate.

As described above, in the inverted-F type antenna of the present invention, the slit 4 is formed where the metal conductor 2 which normally constitutes the antenna must be elongated in order to lower the resonance frequency. Therefore, by removing a portion of the outer side of the metal conductor 2 opposed to the bottom 7 of the slit 4 opposite to the end of the metal conductor 2 where the feeding point 6 and the short-circuit point 5 are formed, the outer periphery of the metal conductor 2 is removed. The depth of the slit 4, that is, the relative distance from the opening of the slit 4 to the bottom 7 with respect to the metal conductor 2 becomes longer, and the resonance frequency can be lowered.

[0017]

Embodiments of the present invention will be described below.

FIG. 1 is a perspective view of an inverted-F antenna according to an embodiment of the present invention. FIGS. 2 and 3 are enlarged views of a part of the inverted-F antenna of FIG. FIG. 7 is an enlarged view showing a part of an inverted-F antenna according to another embodiment.

As shown in FIG. 1, an inverted-F type antenna according to the present invention is different from a plate-shaped substrate formed of a dielectric material 3 and a metal conductor 2 formed on the surface of the substrate on an opposing outer side. From the direction, the dielectric 3 in the center of the metal conductor 2 is rectangular.
Are formed so as to be exposed, and a feed point 6 and a short-circuit point 5 formed adjacent to each other at one end of the metal conductor 2.

The metal conductor 2 is formed by sticking a metal foil or by metal plating. A feed point 6 and a short-circuit point 5 formed on the front surface are formed on the back surface via the plate-shaped dielectric 3. It is exposed and connected to a power supply line and a ground plate formed on the back surface, respectively.

Due to the arrangement of the antenna formed by the metal conductor 2, the feed point 6 and the short-circuit point 5, the above-mentioned antenna is called an inverted F-type antenna.

As shown in FIG. 2, the metal conductor 2 has an outer side opposed to the bottom 7 of the slit 4 closest to the feed point 6 at an end where the feed point 6 and the short-circuit point 5 are formed. A plurality of marks 11 are formed on the opposed portion in parallel with the outer side and at regular intervals from the outer side. This mark 11
Is formed as a first removing portion 9, and by removing the first removing portion 9 along the mark 11 with a constant width from the outer side, the resonance frequency can be reduced at a constant rate. .

As shown in FIG. 3, the metal conductor 2 has, at the other end different from the end where the feeding point 6 and the short-circuit point 5 are formed, a side portion 8 of the slit 4. A plurality of marks 11 are formed on the opposing outer side in parallel with the outer side and at regular intervals from the outer side. The portion where the mark 11 is formed becomes a second removal portion 10. By removing the second removal portion 10 along the mark 11 with a constant width from the outer side, unlike the above-described removal portion 9, the resonance frequency is different. Can be increased at a certain rate.

The mark 11 is formed on the surface of the metal conductor 2 and is formed by drawing on the metal conductor 2 or by processing the metal conductor 2. 2 and 3, the metal conductor 2 is formed by drawing a broken line.

Generally, the resonance frequency of the inverted-F antenna is determined by the peripheral length of the metal conductor 2. However, in the inverted F-type antenna of the present invention, since the slit 4 is formed, as shown in the following embodiment, on the one hand, the resonance frequency changes in proportion to the perimeter of the metal conductor 2, and on the other hand, , The resonance frequency changes in inverse proportion. (Embodiment) The resonance frequency of the inverted-F type antenna shown in FIG. 1 is defined as f0, and the distance from the outer side of the metal conductor 2 to the mark 11 is cut along the mark 11 shown in FIGS. The change amount of the resonance frequency when the metal conductor 2 was removed as the dimensions L1 and L2 was measured.

Table 1 shows the amount of change when the resonance frequency f0 of the inverted F-type antenna 1 before cutting is 800 MHz, and Table 2 shows the amount of change between the resonance frequency f0, the wavelength λ0, and the cut size. This is the result.

[0027]

[Table 1]

[0028]

[Table 2]

As shown in Tables 1 and 2, the inverse F of the present invention
In the type antenna 1, the resonance frequency can be quantitatively reduced by quantitatively removing the metal conductor 2 of the first removing portion 9. Furthermore, by quantitatively removing the metal conductor 2 of the second removing unit 10, the resonance frequency can be quantitatively increased. In the above embodiment, the characteristics were evaluated using the inverted F-type antenna 1 having a resonance frequency of 800 MHz. However, the above-mentioned variation amount depends on the width of the slit 4, the width of the metal conductor 2, and the thickness of the metal conductor 2. different. That is, the contents according to the present invention are not limited to the above embodiment.

FIG. 4 and FIG. 5 show the removing section 9,
FIG. 1 shows an embodiment of a mark 11 formed on a mark 10, wherein the mark 11 is formed by processing a metal conductor 2, and is formed by removing minute slits 12 and 13 by removing a part of the metal conductor 2. It is configured. FIG. 4 shows that the minute slits 12 are formed on two sides adjacent to the outer side, respectively, and the minute slits 12 are formed at positions facing each other, and the cut dimension L is reduced by connecting the bottoms of the opposed minute slits 12. To display.

FIG. 5 shows a structure in which the minute slits 13 are formed intermittently. The minute slits 13 are formed in parallel with the adjacent outer side.
The line connecting 3 indicates the cut dimension.

As described above, according to the inverted F-type antenna 1 of the present invention, it is possible to easily lower or increase the resonance frequency by removing an arbitrary portion of the metal conductor 2 constituting the antenna.

[0033]

According to the inverted F-type antenna according to the first aspect of the present invention, the relative depth of the slit can be adjusted by removing the outer metal conductor facing the bottom of the slit. The resonance frequency of the antenna on which the metal conductor is formed can be lowered by removing a part of the metal conductor.

Further, according to the inverted F-type antenna according to the second aspect of the present invention, the peripheral length of the antenna is shortened by removing the outer metal conductor facing the side portion of the slit formed in the metal conductor, The resonance frequency of the antenna can be increased.

According to the inverted F-type antenna according to the third to fifth aspects of the present invention, the removed portion of the metal conductor removed for adjusting the resonance frequency of the antenna is attached to two sides adjacent to the outer side. Since the opposed minute slits are provided or the marks are provided by minute slits formed in parallel with the outer side and intermittently, the resonance frequency can be easily and quantitatively adjusted.

As described above, according to the inverted-F type antenna of the present invention, even after the metal conductor is formed, the resonance frequency can be raised or lowered and quantitatively adjusted.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inverted-F antenna according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of the inverted-F antenna of FIG. 1;

FIG. 3 is an enlarged view of a part of the inverted-F antenna of FIG. 1;

FIG. 4 is an enlarged view showing a part of an inverted-F antenna according to another embodiment of the present invention.

FIG. 5 is an enlarged view showing a part of an inverted-F antenna according to another embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional inverted F-type antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverted F type antenna 2 Metal conductor 3 Dielectric 4 Slit 5 Short-circuit point 6 Feeding point 7 Bottom 8 Side 9 First removed part 10 Second removed part

Claims (5)

[Claims] 1. An inverted-F type antenna having a metal conductor provided on a surface of a dielectric and having at least one slit in the metal conductor, the antenna resonance being removed by removing an outer metal conductor facing the bottom of the slit. An inverted-F antenna, wherein the frequency can be adjusted to be low. 2. The inverted F-type antenna according to claim 1, wherein a resonance frequency of the antenna can be adjusted to be high by removing a metal conductor on an outer side facing a side portion of the slit. Inverted F-type antenna. 3. The inverted F-type antenna according to claim 1 or 2, wherein a mark is provided at a fixed position from the outer side in a removed portion of the metal conductor to be removed for adjusting a resonance frequency of the antenna. An inverted-F antenna. 4. The inverted F-type antenna according to claim 3, wherein the mark formed on the removed portion of the metal conductor is a minute slit and is formed at a position facing two sides adjacent to the outer side. An inverted-F antenna. 5. The inverted-F antenna according to claim 3, wherein a minute slit is formed in parallel with the outer side and intermittently as a worm.