JP2003243924A - Patch antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly practical patch antenna capable of suppressing spurious radiation from the feeding line wherein downsizing is unaffected even when a continuous strip-shaped feeding line is provided to its patch electrode. <P>SOLUTION: One side of a dielectric board 2 is provided with a patch electrode 3 acting as a radiation element and a feeding line 8 consisting of a meandering strip conductor and continuing to the patch electrode 3. A high frequency signal is supplied to the patch electrode 3 via the feeding line 8, and a ground conductor 5 sufficiently greater than the patch electrode 3 is provided to the other side of the dielectric board 2. Since the feeding line 8 in the patch antenna 11 as above is formed in a manner that the feeding line 8 is a meandering strip shape, a required total length is ensured for the feeding line 8 without the need of increasing the size of the dielectric board 2. Further, when the feeding line 8 is meandered in a crank form, parts whose current directions are opposite to each other are increased, and hence spurious radiation can be suppressed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small patch antenna suitable for use in a GPS (Global Positioning System) or ETC (Automatic Toll Collection) system.

[0002]

2. Description of the Related Art Conventionally, patch antennas of this type are known to have a structure shown in FIG. 4 and a structure shown in FIG.

The patch antenna 1 shown in FIG. 4 has a structure in which miniaturization is prioritized. The patch antenna 1 is provided with a patch electrode 3 as a radiating element on one surface of a dielectric substrate 2, and the patch electrode 3 is provided at a predetermined position. The feeding pin 4 is soldered, and a grounding conductor 5 larger than the patch electrode 3 is provided on the other surface of the dielectric substrate 2 so as to be roughly configured. The power supply pin 4 is electrically connected to an amplifier circuit, a transmission circuit, etc. not shown, and a high frequency signal is supplied to the patch electrode 3 via the power supply pin 4. However, patch electrode 3
Since it is not easy to accurately check in advance which position of the power supply pin 4 should be preferably connected, the patch antenna 1 shown in FIG. 4 is complicated in design and manufacturing control, and the manufacturing cost is correspondingly reduced. There is a problem that it will rise.

On the other hand, the patch antenna 1 shown in FIG.
The patch antenna 10 has a structure in which manufacturing cost and gain are prioritized. The patch antenna 10 includes a patch electrode 3 as a radiating element on one surface of the dielectric substrate 2 and a feed line 6 which is a strip-shaped conductor continuous with the patch electrode 3 for feeding. Is provided to electrically connect the power supply line 6 to an amplifier circuit, a transmission circuit, etc. (not shown) through the through hole 7, and the other surface of the dielectric substrate 2 is grounded sufficiently larger than the patch electrode 3. A conductor 5 is provided. When the high frequency signal is fed to the patch electrode 3 through the feeding line 6 extending from the patch electrode 3 in this way, impedance matching is simplified, and thus design and manufacturing management are facilitated. Therefore, the manufacturing cost can be significantly reduced. Further, in the case of the patch antenna 10 shown in FIG. 5, since the dielectric substrate 2 is large in order to provide the feeding line 6, it is easy to increase the gain by forming the ground conductor 5 having a large area. The total length of the power supply line 6 is set to about 1/4 (λ / 4) of the wavelength λ of the electric wave used on the substrate.

[0005]

As described above, as shown in FIG.
The conventional patch antenna 10 shown in FIG. 1 is advantageous in reducing the manufacturing cost and improving the gain, but the feed line 6 extending in a straight line and having a total length of about λ / 4 must be extended to the patch electrode 3. Therefore, a considerably large dielectric substrate 2 is required, and thus there is a problem in that it is difficult to realize miniaturization, which is indispensable as a vehicle-mounted or portable antenna. In addition, since the radio wave radiated from the power supply line 6 interferes with the radio wave radiated from the patch electrode 3, that is, unnecessary radiation from the power supply line 6 adversely affects the radiation pattern of the patch electrode 3, so that transmission / reception is performed. There was a problem that the radiation pattern of was easily disturbed.

The present invention has been made in view of the circumstances of the prior art as described above, and an object thereof is to provide a continuous strip-shaped power supply line to a patch electrode without impairing miniaturization, and to reduce the size of the power supply line from the power supply line. It is to provide a highly practical patch antenna capable of suppressing unnecessary radiation.

[0007]

In order to achieve the above object, in a patch antenna of the present invention, a dielectric substrate, a patch electrode provided on one side of the dielectric substrate, and a high frequency signal is fed to the patch electrode. And a ground conductor provided on the other surface of the dielectric substrate, and the feed line is composed of a meandering strip-shaped conductor.

The patch antenna configured as described above is
Since the power supply line, which is advantageous for cost reduction and high gain, is formed in a meandering band shape, the total length required for the power supply line can be secured without increasing the size of the dielectric substrate. The miniaturization, which is indispensable as a portable antenna, can be easily realized.

Further, in such a structure, in the case of a patch antenna in which the power feeding line is composed of a strip-shaped conductor meandering in a crank shape or a wavy shape, a power feeding line including many portions in which the directions of currents are opposite or substantially opposite is formed. Therefore, a large amount of radio waves that cancel each other can be emitted from the power supply line, and unnecessary emission can be suppressed as much as possible.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a patch antenna according to a first embodiment of the present invention, and corresponds to FIG. The same reference numerals are given to the parts.

The patch antenna 11 shown in FIG. 1 is provided with a patch electrode 3 as a radiating element and a feed line 8 made of a strip-shaped conductor meandering in a crank shape and continuous with the patch electrode 3 on one surface of a dielectric substrate 2. A ground conductor 5 that is sufficiently larger than the patch electrode 3 is provided on the other surface of the dielectric substrate 2. The power supply line 8 is electrically connected to an amplification circuit, a transmission circuit, etc. (not shown) through the through hole 7.
A high frequency signal is fed to the patch electrode 3 via the feeding line 8. Further, the total length of the power supply line 8 is set to about ¼ of the wavelength λ on the substrate of the radio wave used, but since the power supply line 8 meanders in a crank shape, the distance D from the through hole 7 to the patch electrode 3 is Is λ
It is much shorter than / 4. Therefore, as compared with the conventional patch antenna 10 (see FIG. 5) in which a linearly extending feed line having a total length of about λ / 4 is formed, the patch antenna 11 according to the present embodiment has a dielectric substrate 2 It has become quite small.

As described above, if the high frequency signal is fed to the patch electrode 3 through the feeding line 8 extending from the patch electrode 3, impedance matching is simplified, and therefore, design and The manufacturing control becomes easy, the manufacturing cost can be reduced significantly, and the increase in the area of the ground conductor 5 facilitates the high gain. When the power supply line 8 is formed in a strip shape that meanders in a crank shape as in the present embodiment, the total length required for the power supply line 8 can be secured without making the dielectric substrate 2 excessively large. Therefore, it is possible to easily realize miniaturization, which is indispensable as a vehicle-mounted or portable antenna. Further, since the power supply line 8 meandering like a crank includes many portions in which the directions of current flow are opposite, there is an advantage that there is little interference with the radio waves radiated from the patch electrode 3. That is, since the power supply line 8 contains many radiation components that cancel each other due to the current flowing to the right or left in FIG. 1, unnecessary radiation is extremely large as compared with the power supply line 6 of the conventional product shown in FIG. It's getting less. Therefore, in the patch antenna 11 according to the present embodiment example, the feeding line 8 does not have a bad influence on the radiation pattern of the patch electrode 3, and good antenna performance can be expected.

FIG. 2 is a plan view of a patch antenna according to a second embodiment of the present invention, and FIG. 3 is a plan view of a patch antenna according to the third embodiment of the present invention, which corresponds to FIG. The same reference numerals are given to the parts.

As shown in these figures, the shape of the power supply line 8 is not limited to the above-mentioned crank shape.
For example, as in the patch antenna 12 shown in FIG. 2, even when the power feeding line 8 is formed of a strip-shaped conductor that meanders in a wave shape, the dielectric substrate 2 can be downsized and unnecessary radiation from the power feeding line 8 can be suppressed. Further, in the case where the feeding line 8 is composed of a strip-shaped conductor that meanders in a stepwise manner as in the patch antenna 13 shown in FIG. 3, unnecessary radiation from the feeding line 8 cannot be suppressed, but the dielectric substrate 2 can be downsized. Can be promoted.

[0015]

The present invention is carried out in the form as described above, and has the following effects.

Since the power supply line continuous to the patch electrode is formed in a meandering band shape, it is advantageous not only for cost reduction and high gain, but also easily realizes miniaturization which is indispensable as an on-vehicle or portable antenna. It is possible to provide a highly practical patch antenna.

Further, in the case of the patch antenna in which the power feeding line is composed of a strip-shaped conductor meandering in a crank shape or a wavy shape, it is possible to form a power feeding line including many portions in which the directions of currents are opposite or substantially opposite. Therefore, a large amount of radio waves that cancel each other can be emitted from the power supply line, and unnecessary emission can be suppressed as much as possible.

[Brief description of drawings]

FIG. 1 is a plan view of a patch antenna according to a first exemplary embodiment of the present invention.

FIG. 2 is a plan view of a patch antenna according to a second exemplary embodiment of the present invention.

FIG. 3 is a plan view of a patch antenna according to a third exemplary embodiment of the present invention.

FIG. 4 is a plan view showing a conventional patch antenna without a feeding line.

FIG. 5 is a plan view showing a conventional patch antenna having a feed line.

[Explanation of symbols]

2 Dielectric substrate 3 patch electrodes 5 Ground conductor 7 through holes 8 power supply lines 11, 12, 13 patch antenna

Claims (2)

[Claims] 1. A dielectric substrate, a patch electrode provided on one surface of the dielectric substrate, a power supply line for feeding a high-frequency signal to the patch electrode, and a ground conductor provided on the other surface of the dielectric substrate. A patch antenna, comprising: 2. The patch antenna according to claim 1, wherein the feed line is formed of a strip-shaped conductor meandering in a crank shape or a wave shape.