JPH11122032A - Microstrip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the antenna characteristics of a resonance frequency or the like by adjusting and selecting the dielectric constant of a dielectric, contributing to the wavelength shortening of an electric field generated between a ground conductor and a radiating element and appropriately setting a wavelength shortening effect. SOLUTION: The ground conductor 12 is disposed to one side face of a dielectric substrate 10, a radiating element 14 is disposed to the other side face, a hole 16 of a dimension smaller than the radiating element 14 is perforated on the dielectric substrate 10, covered with the radiating element 14 and the different dielectric provided with the dielectric constant different from the dielectric substrate 10 is disposed to the hole 16. Then, the dielectric constant of a part contributing to the wavelength shortening of the electric field generated between the ground conductor 12 and the radiating element 14 is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables an antenna characteristic such as a resonance frequency to be adjusted by freely selecting a dielectric constant of a dielectric material which contributes to shortening of a wavelength of an electric field generated between a ground conductor and a radiation element. It relates to a microstrip antenna.

[0002]

2. Description of the Related Art FIG. 8 shows a structure of an example of a conventional microstrip antenna. FIG. 8 shows an example of a conventional microstrip antenna, in which (a) is a plan view,
(B) is a sectional view taken along the line AA of (a). In FIG. 8, the conventional microstrip antenna is provided with a ground conductor 12 laminated on one side surface of a dielectric substrate 10. On the other side of the dielectric substrate 10, square radiation elements 14 are also arranged in a stacked state.
By appropriately supplying power to the radiation element 14, an electric field E is generated between the ground conductor 12 and the radiation element 14, and the wavelength of the electric field E is shortened by a wavelength shortening effect corresponding to the dielectric constant of the dielectric substrate 10. Is done. Further, the electromagnetic wave is radiated from the radiation element 14 into the space by the electric field E and functions as an antenna.

[0003]

In the conventional microstrip antenna shown in FIG. 8, the effect of shortening the wavelength applied to the electric field E is determined by the dielectric constant of the dielectric substrate 10. It is known that antenna characteristics such as resonance frequency, gain characteristics, and input reflection band characteristics can be changed by changing the material of the dielectric substrate 10 and changing the dielectric constant that causes this wavelength shortening effect.

Therefore, in order to obtain a desired antenna characteristic such as a resonance frequency, the material of the dielectric substrate 10 must be appropriately selected to obtain an appropriate dielectric constant. However, a dielectric having a desired dielectric constant is not always present, and even if it is present, it may not be possible to select the dielectric from electrical characteristics different from the dielectric constant, economic circumstances, and the like.

[0005] Further, in order to reduce the size and weight of wireless communication equipment, a microstrip antenna may be formed on a part of a printed wiring board on which an electric circuit is mounted. In such a case, a printed wiring board is used as the dielectric substrate 10. However, the dielectric constant of the printed wiring board is not always appropriate, and it is difficult to obtain desired antenna characteristics.

The present invention has been made in view of the circumstances of the prior art microstrip antenna as described above,
It is an object of the present invention to provide a microstrip antenna capable of appropriately adjusting the wavelength shortening effect.

[0007]

In order to achieve the above object, a microstrip antenna according to the present invention has a microstrip in which a ground conductor is provided on one side of a dielectric substrate and a radiation element is provided on the other side. At the antenna
A part of the dielectric substrate, which part contributes to shortening of the wavelength of an electric field generated between the ground conductor and the radiation element, is replaced with the dielectric substrate, and has a different dielectric from the dielectric substrate. It is configured by disposing another dielectric material having a ratio.

Then, a hole having a size smaller than, equal to, or larger than the radiation element is formed in a portion of the dielectric substrate facing the radiation element, and the another dielectric made of solid is disposed in the hole. It may be constituted by.

Further, a hole smaller in size than the radiation element is formed in a portion of the dielectric substrate covered by the radiation element, and air is disposed in the hole as the another dielectric. Can also.

Further, the radiation element is square,
It is also possible that the hole is a rectangle whose four sides are parallel to the square.

[0011]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. 1A and 1B show a first embodiment of a microstrip antenna according to the present invention, wherein FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view of FIG. 1, the same or equivalent members as those in FIG. 8 are denoted by the same reference numerals, and redundant description will be omitted.

The first embodiment shown in FIG. 1 is different from the conventional example shown in FIG. 8 in that a portion of the dielectric substrate 10 covered by the square radiating element 14 has a square smaller in size than the radiating element 14. Hole 16 is formed. This hole 16 is filled with air as a dielectric having a dielectric constant of “1”. In the structure of the first embodiment, part of the electric field E generated between the ground conductor 12 and the radiation element 14 has a wavelength shortening effect due to the dielectric constant of the dielectric substrate 10, and the other part has an effect. A wavelength shortening effect is given by the dielectric constant of the air in the hole 16. As a result, according to the size and the shape of the hole 16, the dielectric constant for producing the wavelength shortening effect as a whole can be appropriately set within the range from the dielectric constant of the dielectric substrate 10 to the dielectric constant of air. Thus, the same wavelength shortening effect as that obtained by using the dielectric substrate having the dielectric constant can be obtained. Thus, the dielectric substrate 10 as an actual constituent member
Without being limited to the above dielectric constant, the dielectric constant that produces the wavelength shortening effect as a whole can be set to a desired value, and the antenna characteristics such as the resonance frequency can be arbitrarily set.
In the first embodiment, the ground conductor 12 and the radiating element 14 facing the hole 16 can of course retain their shapes by themselves.

FIG. 2 is a sectional view of a second embodiment of the microstrip antenna according to the present invention. In the second embodiment, the holes 16 formed in the dielectric substrate 10 in the first embodiment are
A second dielectric 18 such as styrene foam, which is a solid having a dielectric constant different from that of the dielectric substrate 10, is inserted. The second dielectric 18 may have a dielectric constant higher or lower than the dielectric constant of the dielectric substrate 10. By providing the second dielectric 18, the ground conductor 12 and the radiation element 14 are reliably supported, and a robust configuration can be achieved. If the second dielectric 18 has a dielectric constant smaller than that of the dielectric substrate 10, the waveform shortening effect is also small, and if the dimensions of the radiation elements 14 are the same, the conventional dielectric of FIG. A higher frequency can be resonated than a microstrip antenna. If a second dielectric 18 having a large dielectric constant is used, lower frequencies can be resonated. In the second embodiment, the size of the hole 16 is
The size is not limited to one smaller than the radiation element 14 and may be the same or larger.

FIG. 3 is a plan view of a third embodiment of the microstrip antenna according to the present invention. In the third embodiment, the hole 20 formed in the dielectric substrate 10 is
It is a rectangle having sides parallel to each other. By making the hole 20 rectangular, even if the radiation element 14 is square, the electric field Ea and the electric field Eb on the long side and the short side differ in the wavelength shortening effect received by the electric field, and the long side direction and the short side direction have different effects. The resonance frequencies are different. Therefore, the radiation element 14 functions as a two-frequency resonance antenna even though it is square.

FIG. 4 shows a fourth embodiment of the microstrip antenna according to the present invention, wherein FIG.
(B) is a sectional view taken along the line CC of (a). In the fourth embodiment, a third dielectric 22 having a dielectric constant different from that of the dielectric substrate 10 is inserted into a hole 16 formed in the dielectric substrate 10, and further inserted into the third dielectric 22. A fourth dielectric 24 having a dielectric constant different from that of the dielectric substrate 10 and the third dielectric 22 is inserted into the formed hole. The dielectric constant as a whole can be finely adjusted by the fourth dielectric 24.

FIG. 5 is a sectional view of a microstrip antenna according to a fifth embodiment of the present invention. In the fifth embodiment, the fifth dielectric 26 is inserted into the half of the ground conductor 12 side in the hole 16 formed in the dielectric substrate 10, and the half of the hole 16 on the radiation element 14 side is The air is full.

FIG. 6 is a sectional view of a microstrip antenna according to a sixth embodiment of the present invention. In the sixth embodiment, a recess 28 that does not penetrate through the dielectric substrate 10 is provided instead of the hole 16. The recess 28 may be provided on either the side of the ground conductor 12 or the side of the radiation element 14. Then, as shown in FIG. 6, the concave portion 28 may be filled with air, or another dielectric material having a different dielectric constant from the dielectric substrate 10 may be inserted.

FIG. 7 is a plan view of a microstrip antenna according to a seventh embodiment of the present invention. In the seventh embodiment, the radiation element 30 is circular.
The radiation element 3 is placed on the portion of the dielectric substrate 10 covered with
A circular hole 32 having a diameter smaller than 0 is formed. The hole 32 is filled with air, and the dielectric substrate 1
Another dielectric having a dielectric constant different from zero may be inserted. Further, instead of the hole 32, a circular concave portion may be formed as in the sixth embodiment.

In the above embodiment, the dielectric substrate 1
In the holes 16, 20, 32 and the concave portion 28 provided in the hole 0, any dielectric containing air having a dielectric constant different from that of the dielectric substrate 10 may be provided. Of course, it is not limited to this.

[0020]

As described above, since the microstrip antenna of the present invention is constituted, the following special effects can be obtained.

In the microstrip antenna according to the first aspect, since a part of the dielectric substrate is disposed in place of another dielectric having a different dielectric constant, the effect of shortening the wavelength as a whole changes. The same characteristics as when a microstrip antenna is formed using a dielectric substrate having an arbitrary permittivity can be obtained. Therefore, the antenna characteristics such as the resonance frequency can be arbitrarily set without being restricted by the dielectric constant of the dielectric substrate as a constituent member.

Further, in any of the microstrip antennas according to the second and third aspects, another dielectric material having a different dielectric constant is provided on a portion of the dielectric substrate covered or facing the radiation element. Therefore, the dielectric constant of this another dielectric can greatly contribute to the wavelength shortening effect. Thus, by providing another dielectric, it is possible to effectively adjust and change the antenna characteristics.

Furthermore, in the microstrip antenna according to the third aspect, the holes formed in the dielectric substrate are rectangular, so that two frequencies resonate even though the radiation element is square. Can be.

[Brief description of the drawings]

1A and 1B show a first embodiment of a microstrip antenna according to the present invention, wherein FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view of FIG.

FIG. 2 is a sectional view of a microstrip antenna according to a second embodiment of the present invention.

FIG. 3 is a plan view of a third embodiment of the microstrip antenna of the present invention.

4A and 4B show a microstrip antenna according to a fourth embodiment of the present invention, wherein FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view of FIG.

FIG. 5 is a sectional view of a microstrip antenna according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a microstrip antenna according to a sixth embodiment of the present invention.

FIG. 7 is a plan view of a microstrip antenna according to a seventh embodiment of the present invention.

8A and 8B show an example of a conventional microstrip antenna, in which FIG. 8A is a plan view, and FIG. 8B is a cross-sectional view of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 dielectric substrate 12 ground conductor 14, 30 radiation element 16, 20, 32 hole 18 second dielectric 22 third dielectric 24 fourth dielectric 26 fifth dielectric 28 recess

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Rikuo Shimamori 7-5-11 Takinogawa, Kita-ku, Tokyo Inside Yokoo Co., Ltd.

Claims (4)

[Claims] 1. A microstrip antenna in which a ground conductor is provided on one side surface of a dielectric substrate and a radiation element is provided on another side surface, wherein:
A part of a portion that contributes to shortening of the wavelength of an electric field generated between the ground conductor and the radiation element is replaced with the dielectric substrate, and another dielectric having a different dielectric constant from the dielectric substrate is provided. A microstrip antenna characterized by comprising: 2. The microstrip antenna according to claim 1, wherein a hole having a size smaller than, equal to, or larger than the radiation element is formed in a portion of the dielectric substrate facing the radiation element, and the hole is made of solid material. A microstrip antenna, wherein said another dielectric is provided. 3. The microstrip antenna according to claim 1, wherein a hole smaller in size than the radiation element is formed in a portion of the dielectric substrate covered by the radiation element, and air is supplied to the another hole. A microstrip antenna, wherein the microstrip antenna is provided as a dielectric. 4. The microstrip antenna according to claim 2, wherein said radiation element is a square, and said hole is a rectangle whose four sides are parallel to said square.