JPH061849B2 - Small microstrip antenna loaded with metal rod - Google Patents

Description

TECHNICAL FIELD The present invention relates to a structure of a small microstrip antenna having a disk-shaped center conductor.

INDUSTRIAL APPLICABILITY The present invention is used for a feed element of a component antenna of an array antenna or an antenna with a reflector, which is used in a frequency band higher than a super high frequency.

〔Overview〕

The present invention provides a microstrip antenna comprising a flat ground conductor and a disk-shaped center conductor arranged in parallel with each other, and an electrical connection to either of these two conductors is made between the ground conductor and the center conductor. By arranging one or more metal rods connected to, when used as a single unit, it is small and has a wide operating frequency band under a constant voltage standing wave ratio. Is an array antenna with a small required area.

[Conventional technology]

A conventional antenna of this type is, for example, a ground conductor 1, a dielectric 2 and a center as shown in U.S. Pat. No. 3,921,177 (November 18, 1975) "Structure and Array of Microstrip Antenna" shown in FIG. If the relative permittivity of the dielectric body 2 is ε _r and the wavelength used is λ, the length of one side of the central conductor plate 3 ′ that is composed of the conductor plate 3 ′ is I needed to.

FIG. 9 is a vertical cross-sectional view of another conventional micro-slip antenna, in which the center conductor 3 is a disk type and the feed line 4 is the lower side of the ground conductor 1. And is connected to the central conductor 3 through the small hole. In this case, the diameter of the central conductor 3 had to be about the same as that shown in FIG.

On the other hand, when a multi-beam is generated in an antenna with a reflector using the above-mentioned microstrip antenna as a feed element and a multi-beam is to be set to an arbitrary value for each beam interval, the power is fed according to the size of the beam interval. It is necessary to make the element spacing large or small, respectively.

[Problems to be solved by the invention]

However, the size of the microstrip antenna as a feeding element is limited by the wavelength used as in the above equation, and conversely, if the relative permittivity ε _{r of the} dielectric is increased, the radiation efficiency decreases, so the beam spacing can be sandwiched below a certain value. There was a drawback that could not be done.

The present invention solves this drawback, and can be used as an element antenna of an array antenna to miniaturize the array antenna, and further can be used as an element antenna for an antenna with a reflector to form a multi-beam antenna with an arbitrary beam interval. An object is to provide a rod-loaded small microstrip antenna.

[Means for solving problems]

The metal rod-loaded small-sized microstrip antenna according to the present invention has a ground conductor, a disc-shaped center conductor, a metal rod, and a coaxial feed portion, and the metal rod reacts between the ground conductor and the disc-shaped center conductor. It is characterized by having a means for loading a minute.

That is, the present invention provides a microstrip antenna in which a plate-shaped ground conductor and a disk-shaped center conductor are arranged in parallel, and the center conductor is connected to a feed line. It is arranged on the line connecting the center point of the disk and the feeding point in the gap between the conductor and the center conductor, and the metal rod is electrically connected to either the ground conductor or the center conductor. Characterize.

[Action]

If the wavelength used for the microstrip antenna is fixed, the size of the center conductor is inversely proportional to the square root of the relative permittivity of the dielectric between the center conductor and the ground conductor, but the relative permittivity is reduced to reduce the size of the center conductor. However, the radiation efficiency of the antenna decreases with increasing. Therefore, by disposing a metal rod in the gap between the central conductor and the ground conductor to give a reactance component, the central conductor can be downsized.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view of a first embodiment of the present invention, and FIG. 2 is a top view thereof.

In both figures, the ground conductor 1 is arranged in parallel with the disk-shaped center conductor 3 through the dielectric 2, and the linear conductor 4 whose one end is connected to the center conductor 3 serves as the center conductor of the coaxial line (not shown). Connected.

The feature of the present invention resides in that one or a plurality of metal rods 5, one end surface of which is connected to the ground conductor 1, are arranged in the dielectric 2.

As an example, the figure shows a case where four metal rods 5 are arranged.

In FIG. 1, a dielectric having a relative dielectric constant of about 1 is used, and in the case where there is no metal rod 5, the disc-shaped center conductor 3 has a right angle of 10 cm, and the distance between the ground conductor 1 and the center conductor 3 is set to 10 cm. According to the experiment, the optimum radiable frequency when 7 mm is 1.
It was 57 GHz.

Next, when the diameter of the central conductor 3 is set to 8 cm and the four metal rods 5 are arranged at an equal interval of 1 / 16λ, the reactance component is loaded between the central conductor 3 and the metal rods 5 close to the central conductor 3, so that radiation occurs. It was confirmed by experiments that the possible optimum frequency is 1.60 GHz.

That is, by loading the metal rod 5 to the desired frequency of use, it becomes possible to perform transmission / reception using the center conductor having a small diameter of about 20%.

It was also confirmed by experiments that the frequency bandwidth for a constant voltage standing wave ratio is about 20% wide.

FIG. 3 is a vertical cross-sectional view of the second embodiment of the present invention.
The figure is a top view thereof. It differs from the embodiment of FIG. 1 in that one end of the metal rod 5 is connected to the central conductor 3, but
By loading the reactance component in the same manner as in the figure, the diameter of the central conductor can be reduced and the band can be widened.

FIG. 5 is a vertical cross-sectional view of the third embodiment of the present invention.
The figure is a top view thereof. FIG. 5 shows a structure in which the conductor rod 6 supporting the central conductor 3 in FIG. 1 is connected to the ground conductor 1 along the central axis of the central conductor 3, and this position corresponds to the node part of the high frequency electric field, so that it is electrically connected. Has little adverse effect on. FIG. 7 is a top view of a circularly polarized antenna of another embodiment in which the metal rods 5 are arranged at 90 ° intervals.
Other types of circularly polarized antennas can be configured depending on the positional relationship between the linear conductor 4 and the linear conductor 4.

Further, in the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 3, the plurality of metal rods are electrically connected to either the ground conductor or the center conductor. A part of the metal rod may be connected to the ground conductor and the remaining metal rod may be connected to the center conductor.

The present invention is not limited to each of the embodiments,
For example, it is obvious that the present invention can also be applied to a microstrip antenna in which a notch is partially provided on the outer periphery of a disk-shaped center conductor.

〔The invention's effect〕

As described above, the metal rod-loaded microstrip antenna of the present invention can reduce the diameter of the disk-shaped center conductor as compared with the conventional one by providing the metal rod. It becomes possible to arrange a large number of conductors closer to each other as compared with the conventional one.

Therefore, in a multi-beam antenna in which a plurality of the elements of the present invention are used as a feeding element and combined with a reflecting mirror, each beam interval can be made narrower than that of a conventional antenna. Further, since a plurality of disk-shaped center conductors can be arranged on one fixed ground conductor without using a reflecting mirror as compared with the conventional one, it is possible to construct an array antenna having a smaller size than the conventional one and having the same performance. Further, on the other hand, since the frequency band can be widened for a constant voltage standing wave ratio, there is an effect that a single microstrip antenna that is not used because of a narrow band in the related art can be actually used.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the first embodiment of the present invention. FIG. 2 is a top view of the above embodiment. FIG. 3 is a longitudinal sectional view of the second embodiment of the present invention. FIG. 4 is a top view of the above embodiment. FIG. 5 is a vertical sectional view of the third embodiment of the present invention. FIG. 6 is a top view of the above embodiment. FIG. 7 is a front view of another embodiment of the present invention. FIG. 8 is a perspective view of a conventional example. FIG. 9 is a vertical sectional view of another conventional example. 1 ... Ground conductor, 2 ... Derivative, 3 ... Disc type center conductor, 3 '
... rectangular center conductor, 4 ... linear conductor, 5 ... metal rod, 6 ...
A linear conductor that connects the ground conductor and the center conductor.

Claims (1)

[Claims] 1. A microstrip antenna in which a plate-shaped ground conductor and a disk-shaped center conductor are arranged in parallel, and the center conductor is connected to a power supply line, wherein one or more metal rods are the above ground. It is arranged on the line connecting the center point of the disc and the feeding point in the gap between the conductor and the center conductor, and the metal rod is electrically connected to either the ground conductor or the center conductor. A characteristic microstrip antenna loaded with a metal rod.