JPH03192804A - Antenna system - Google Patents

Abstract

PURPOSE:To realize an antenna with high gain in spite of small size and light weight by increasing the dielectric constant of a dielectric substance in existence between a ground plate and at least a part of a radiation element surrounding part more than the dielectric constant of the dielectric substance in existence between the ground plate and the radiation element in addition to the said dielectric substance. CONSTITUTION:The dielectric constant of 1st dielectric substances 7, 7a inserted between a ground plate and a radiation element surrounding part is increased more than the dielectric constant of a 2nd dielectric substance filling a part other than the 1st dielectric substance between the ground plate and the radiation element. In figure, rounds shown in caption 10 depict the actual measurement data and caption 11 indicates an approximated curve based on the actual measurement data, and then it is recognized as the 1st dielectric substance is inserted deeper, the resonance frequency is lowered more. That is, since a substance with a small specific gravity such as air is used for the dielectric substance having a low dielectric constant, the volume of the dielectric substance with a comparatively large specific gravity having a high dielectric constant is reduced to make the weight of the antenna light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a microstrip 7 antenna or a plate-shaped inverted F antenna, and particularly to the structure of an antenna that is small and lightweight and can obtain high gain. It is something.

[Conventional technology]

FIG. 12 is a diagram showing an example of a conventional rectangular microstrip antenna, in which 51 is a radiating element, 52 is a ground plane, 53 is a dielectric inserted between the radiating element and the ground plane, 54 is a feeding point, and 55 is a radiating element. It represents the length of the element.

The resonance condition of the antenna shown in the figure is that the length of the radiating element is 55
Gahoba λ. /2 (person. Effective wavelength on two substrates).

That is, if an air layer is used instead of the dielectric 53, the length of the radiating element will be approximately 15 cm at IGHz. Therefore, miniaturization is generally achieved by filling the space between the radiating element and the ground plane with a dielectric material.

[Problem to be solved by the invention]

As mentioned above, in an antenna configured to fill the space between the radiating element and the ground plane with a dielectric material, for example, when ε (relative dielectric constant) = 15, the length of the radiating element at IGHz is approximately 7 cm. Become. However, when the antenna is made smaller in this way, there are disadvantages in that the antenna becomes heavier due to filling with dielectric material, and the gain also decreases because the antenna shape becomes smaller.

Further, a plate-shaped inverted F antenna can also be made smaller in the same way, but it has the same drawbacks as the microstrip antenna.

SUMMARY OF THE INVENTION In view of these conventional problems, an object of the present invention is to provide a microstrip antenna or a plate-shaped inverted F antenna that is small and lightweight and has a high gain.

[Means to solve the problem]

In order to achieve the above object, the present invention has the dielectric constant of a dielectric material existing between at least a part of the peripheral portion of the radiating element of a microstrip antenna or a plate-shaped inverted F antenna and the ground plane to a radiating element other than the dielectric material. It is constructed so that the dielectric constant is higher than that of the dielectric material existing in the open part of the ground plane.

Hereinafter, the effects and the like of the present invention will be explained in detail based on Examples.

〔Example〕

FIG. 1 is a diagram showing a first embodiment of the present invention, in which 1 is a radiating element, 2 is a ground plane, 4 is a feed point, 5 is a height of the radiating element, 6 is a width of the radiating element, and 77a is a diagram showing a first embodiment of the present invention. A first dielectric is inserted between the surrounding area of the radiating element and the ground plane, 8 is a second dielectric that fills the area other than the first dielectric between the radiating element and the ground plane, and 9 is the radiating element. It represents the length of the overlapping portion of the first dielectric. The dielectric constant of the first dielectric 77a shown in the figure is higher than the dielectric constant of the second dielectric 8.

In an antenna with such a structure, the length of the radiating element is 5
is 10cm, the width 6 is 6c-, and the first dielectric 7 7
As a, 8 pieces (relative dielectric constant) of 15 are used, the second dielectric 8 is air, and the radiating element 1 and the first dielectric 7, 7 are used.
FIG. 2 shows the results of investigating the relationship between the length 9 of the overlapping portion with a and the resonance frequency.

In the figure, the circle mark 10 indicates actual measurement data, and 11 indicates an approximate curve based on the actual measurement data. According to this, the deeper the first dielectric is inserted, the lower the resonant frequency is. I know what I'm going to do.

Furthermore, based on this result, in order to obtain the same resonant frequency, it is possible to mount a dielectric material with a high dielectric constant partially as in this example and mount the same dielectric material as in the conventional example. Figure 3 shows a comparison of the weights of the antennas in these cases.

In the figure, the number 12 indicates data when the dielectric material with a high dielectric constant of this embodiment is partially mounted, and the number 13 indicates data with the conventional low permittivity dielectric material. This is data when the entire area is filled with dielectric material. From this figure, in order to obtain the same resonant frequency, it is better to partially mount a dielectric material with a high permittivity as in the present invention.
It can be seen that it is lighter than if all the grooves were filled with dielectric material having a low dielectric constant.

That is, in the antenna of the present invention, air or a substance with a low specific gravity can be used as the dielectric material having a low permittivity, so that the volume of the dielectric material having a relatively large specific gravity and a high permittivity can be reduced. , it is possible to reduce the weight of the antenna.

Next, FIG. 4 shows the state of the open electric field between the radiating element and the ground plane.

In the figure, 1 is a radiating element, 2 is a ground plane, 4 is a feeding point,
7 and 7a represent a first dielectric with a high dielectric constant, and 8 represents a second dielectric with a lower dielectric constant than the first dielectric; these are the same as in Figure 1. . As described above, in this embodiment, since the dielectric material having a high dielectric constant is present in the radiating esso part, the electric field is concentrated there, as indicated by the arrow in the figure, and the gain increases.

That is, by partially mounting a dielectric material having a high dielectric constant as in this embodiment, it is possible to realize a small, lightweight, and high-gain antenna.

FIG. 5 is a diagram showing a second embodiment of the present invention, 1
a is the radiating element, 2a is the ground plane, 4a is the feeding point, 5a is the length of the radiating element, 6a is the width of the radiating element, 7b and 7c are the first dielectric bodies inserted between the surrounding area of the radiating element and the ground plane. ,8a
9 represents a second dielectric filling the area other than the first dielectric between the radiating element and the ground plane, and 9 & represents the length of the overlapping portion of the radiating element and the first dielectric.

The dielectric constants of the first dielectrics 7b and 7e shown in the figure are higher than the dielectric constant of the second dielectric 8a.

This embodiment differs from the first embodiment in that a high dielectric material is partially mounted in the width direction of the radiating element. It's the best.

In this example, the length 5a of the t-element is 10c■,
The width is 6c-, the first dielectrics 7b and 7C are 6 dielectric constants (relative permittivity) = 15, and the second dielectric 8a is air, and the overlapping part of the radiating element and the first dielectric is FIG. 6 shows the results of investigating the relationship between the height 9a and the resonance frequency.

In the same figure, the circle indicated by the number group 14 indicates the case where only one side of the dielectric (7b or 7c) is made of a high dielectric material.
The black circles shown in the number group 15 are the dielectrics on both sides (7b and 7
The data is shown when c) is a high dielectric material.

From the figure, it can be seen that in this example as well, the resonant frequency is lowered and the antenna is made smaller. but,
In this case, since the dielectric material having a high dielectric constant is not partially mounted only on the radiation edge portion, the gain increasing effect is not as great as in the first embodiment.

Further, the same effect can be obtained by combining the first embodiment and the second embodiment and partially mounting a dielectric material having a high dielectric constant all around the radiating element.

FIG. 7 is a diagram showing a third embodiment of the present invention, 1b
is the radiating element, 2b is the ground plane, 4b is the feeding point, 7d and 7e are the first dielectrics inserted between the radiating element peripheral part and the ground plane, and 8b is the opening between the radiating element and the ground plane other than the first dielectric. represents the second dielectric filling the area.

The dielectric constants of the first dielectrics 7d and 7e are higher than the dielectric constant of the second dielectric 8b, and the dielectric constants are gradually changing.

An example of the change in permittivity depending on the position of the dielectric material in this example is shown in the eighth example.
Shown in the figure.

In the figure, (a) shows the cross section of the antenna, (b) shows the characteristics of change in dielectric constant in correspondence with (a), and the group of numbers 16 shows the characteristics of change in permittivity.

The change in dielectric constant does not have to be linear as shown in FIG. 8, and there is also a method of changing it trigonometrically. In this case as well, the dielectric constant around the radiating element is high, while the dielectric constant at the center is low, so it is clear that the same effect as in the first embodiment is obtained.

Furthermore, since the dielectric constant changes continuously, the frequency characteristics are excellent and the bandwidth is wide.

Further, to obtain the same effect, the first high dielectric material and the second low dielectric material may be combined in a tapered shape, as shown in Figure $9.

In the figure, 1c is the radiating element, 2c is the ground plane, 4c is the feed point, 7ft7g is the first dielectric inserted between the radiating element peripheral part and the ground plane, and 8c is the first dielectric between the radiating element and the ground plane. It represents a second dielectric filling the area other than the dielectric.

In this structure, the first high dielectric material 7f.

By joining 7g and the second low dielectric material 8c in a tapered shape, it is equivalent to the case where the dielectric constant gradually changes as in the third embodiment. As shown in FIG. 9, the joining method of the first dielectric material having a high dielectric constant and the second dielectric material having a low dielectric constant is not limited to a linear Taber, but a trigonometric method. There are also methods such as combining them on curved surfaces.

That is, as in this example, a dielectric material whose permittivity changes partially is mounted and the permittivity changes continuously, or the permittivity is changed continuously by combining dielectric materials in a tapered shape. As a result, while being small and lightweight,
A high gain and wideband antenna can be realized.

FIG. 10 is a diagram showing a fourth embodiment of the present invention, and is an embodiment in the case of a plate-shaped inverted F antenna.

In the figure, 1d is the radiating element, 2d is the ground plane, 4d is the feeding point, 7h is the first dielectric inserted between the radiating element peripheral part and the ground plane, and 8d is the first dielectric between the radiating element and the ground plane. A second dielectric 17 filling the area other than the dielectric represents a stub connecting the radiating element 1d and the ground plane 2d.

The dielectric constant of the first dielectric 7h is higher than that of the second dielectric 8d, and in this case also the dielectric constant around the radiating element is
On the other hand, since the dielectric constant at the center is low, it is clear that the same effect as in the first embodiment is obtained.

That is, even in the case of a plate-shaped inverted F antenna, a small and lightweight antenna can be realized by partially mounting a dielectric material having a high dielectric constant as in this embodiment.

FIG. 11 is a diagram showing a fifth embodiment of the present invention, in which the present invention is applied to a circular microstrip antenna.

In the same figure, 1e is a radiating element, 4e and 4f are power feeders, 7e to 7q are first dielectrics inserted into the opening between the radiating element and the ground plane, and 8e is the first dielectric between the radiating element and the ground plane. represents a second dielectric filling the part other than the dielectric. The dielectric constants of the first dielectrics 7e to 7q are higher than the dielectric constant of the second dielectric 8e.

In the figure, (&) indicates when a dielectric material having a high permittivity is used uniformly around the radiating element, and (b) indicates when a dielectric material having a high permittivity is made circularly around the area where the electric field is concentrated. c)
is the same as (b), but when power is fed at two points and polarization is shared, (d) is when only the part where the electric field is concentrated is made of a fan-shaped dielectric with a high permittivity, (e) is (d) and
Although it is similar, an example is shown in which power is supplied at two points and polarization is shared.

In the case of this example as well, the first dielectric and the second dielectric are simply joined by butting the straight cross sections of the first dielectric and the second dielectric. The following methods can be adopted.

Furthermore, in the case of a plate-shaped inverted F antenna, several methods of partially mounting high dielectric materials can be considered based on the same concept as in this embodiment.

Any of these can achieve the same effect as the first or second rectangular microstrip antenna.

〔Effect of the invention〕

As explained above, according to the present invention, the dielectric constant of the first dielectric material existing between at least a part of the peripheral portion of the radiating element of a microstrip antenna or a plate-shaped inverted F antenna and the ground plane is By making the dielectric constant higher than the dielectric constant of the dielectric material existing between the radiating element and the ground plane, the weight of the conventional microstrip antenna or plate-shaped inverted F antenna is reduced when the size is reduced. It is possible to eliminate the drawbacks of increase in gain and decrease in gain, and there is an advantage that a high gain antenna can be realized while being small and lightweight.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the first embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the length of the overlapping portion of the radiating element and the first dielectric and the resonant frequency, and FIG. FIG. 4 is a diagram showing the state of the open electric field between the radiating element and the ground plane; FIG. 5 is a diagram showing the second embodiment of the present invention; FIG. Fig. 6 is a diagram showing the relationship between the length of the overlapping portion of the radiating element and the first dielectric material and the resonance frequency in the second embodiment, Fig. 7 is a diagram showing the third embodiment of the present invention, and Fig. 8 9 is a diagram showing a change in the permittivity of a dielectric material according to a third embodiment of the present invention, FIG. 9 is a diagram showing a modification of the third embodiment, and FIG. 10 is a diagram regarding a fourth embodiment of the present invention. 11 is a diagram showing a fifth embodiment of the present invention, and FIG. 12 is a diagram showing an example of a conventional rectangular microstrip 7 antenna. 1.1a to 1f...radiating element, 2 2a
~ 2d... Main plate, 4.3a ~ 4d...
... Feeding point, 5 5 m ... Length of radiating element, 6 6 m ... Width of radiating element, 7 7 a ~
7q...The first dielectric inserted between the surrounding area of the radiating element and the ground plane, 8 8a to 8e...The area between the radiating element and the ground plane other than the first dielectric Second dielectric that satisfies the following: 9 9a...Tightness of the overlapping part of the radiating element and the first dielectric, 10...Actual measurement data, 11...・Approximate curve based on actual measurement data, 12...Data when dielectrics with high permittivity are partially mounted, 13...All dielectrics with low permittivity are mounted 14...Data when only one side is made of a dielectric material with a high permittivity, 15......Data when both sides are made of a dielectric material with a high permittivity. Data, 16... Characteristics showing changes in permittivity 17...
···stub

Claims (1)

[Claims] In an antenna device in which one of two conductor plates having a sufficiently narrow interval compared to the wavelength is used as the ground plate and the other is used as the radiating element, the dielectric of the dielectric material that exists between at least a part of the surrounding area of the radiating element and the ground plate. An antenna device characterized in that the dielectric constant is higher than that of a dielectric material other than the dielectric material that exists between the radiating element and the ground plane.