JP2000236216A - Microstrip array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microstrip array antenna which can simplify a feed line, reduce loss of the feed line, and secure a sufficient gain. SOLUTION: Four feed elements 12a to 12d are arranged at respective corner parts on the top surface of a dielectric substrate 11, and nonfeed elements 13a to 13e are arranged between the feed elements 12a to 12d and at their center parts at specific intervals. On the reverse-surface side of the dielectric substrate 11, a conductor ground plate is laminated, and a 4-distributor is arranged facing opposite. Electric power distributed into four by this 4-distributor is supplied in an equal-amplitude and in-phase state to the feed elements 12a to 12d by the feed lines to feed points 15a to 15d of the feed elements 12a to 12d passing through the conductor ground plate, and dielectric substrate 11 and electromagnetic waves of necessary frequency are radiated from the feed elements 12a to 12d. At this time, electromagnetic waves of the same frequency with the feed elements 12a to 12d are radiated by the nonfeed elements 13a to 13e through the coupling between the feed elements 12a to 12d and nonfeed elements 13a to 13e.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip array antenna for performing data communication in a near field of several cm to several meters in a quasi-microwave and microwave band.

[0002]

2. Description of the Related Art In recent years, an electronic tag (unpowered) composed of a combination of an IC chip and an antenna is attached to, for example, an article, information unique to each article is written in the IC chip in advance, and the stored information is required. By reading according to
A management system for managing articles has been developed.

[0003] In the management system using the electronic tag as described above, an array antenna having one to two or more elements is generally used as an antenna for performing data communication with the electronic tag. In order to extend the data communication distance, it is effective to increase the antenna gain,
As a typical antenna, a microstrip array antenna which can be formed compactly in a plane and has an easy beam shaping has been conventionally known.

FIG. 6 shows a configuration example of a conventional four-element microstrip array antenna.
6, reference numeral 1 denotes a dielectric substrate, and four antenna elements 2a to 2d are arranged on the upper surface of the dielectric substrate 1 at predetermined intervals. A conductor ground plate (not shown) is provided on the back side of the dielectric substrate 1. Then, power is supplied to the feeding points 3a to 3d of the antenna elements 2a to 2d from the back surface side of the dielectric substrate 1.

In the array antenna configured as described above, when the electronic tag is located at a sufficiently short distance, communication is performed by the element closest to the electronic tag among the plurality of elements 2a to 2d, and the antenna is separated to some extent. At a distance, communication is performed using a combined electromagnetic wave.

[0006]

In the above-mentioned microstrip array antenna, in the case of communication in the near field such as a management system using an electronic tag, if the element spacing is increased to a certain extent or more, for example, the elements 2a, 2c and 2
The distance between b and 2d is d1, and the elements 2a and 2b and 2c and 2d
Is set to 0.6λ or more, the distance (d1) / 2, (d2)
/ 2, that is, there is a problem that communication cannot be performed near the center between the elements. This problem becomes more conspicuous as the element spacing increases.

[0007] When each of the elements 2a to 2d is set to be narrow, for example, when each of the element intervals d1 and d2 is set to be smaller than 0.5λ, the above-described problem is reduced. . S. W. Problems such as deterioration of R and decrease of gain occur, and there is a problem that the communication distance does not increase. This problem becomes more conspicuous as the element spacing becomes smaller.

Further, when the number of elements is increased, the feed line becomes longer and the gain is reduced due to the loss of the feed line, and when the spacing between the elements is reduced, the wiring of the feed line becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a microstrip array antenna which can simplify a feed line, reduce a loss in the feed line, and secure a sufficient gain. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a microstrip array antenna having a plurality of antenna elements arranged on the same plane, wherein the antenna elements include a feed element and a parasitic element arranged close to each other. It is characterized by comprising.

A second invention is characterized in that a parasitic element is arranged between the feed elements as the antenna element in the first invention.

A third aspect of the invention is characterized in that at least one or more parasitic element is arranged around the feed element as the antenna element in the first aspect.

According to a fourth aspect of the present invention, in the microstrip array antenna according to the first, second, or third aspect, the power supply is distributed to the power supply points of the power supply elements by a distributor.

According to a fifth aspect of the present invention, in the microstrip array antenna according to the first, second, or third aspect, the feed power is distributed to feed points of each feed element by a microstrip line.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a plan view of a microstrip array antenna according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. This embodiment shows an example in which nine antenna elements are arranged. 1 and 2, reference numeral 11 denotes, for example, a rectangular dielectric substrate, and four feed elements 12a to 12d are provided on the upper surface of the dielectric substrate 11 at each corner.
And the four feed elements 12a to 12
Parasitic elements 13a to 13e are arranged between and at the center of d. In this case, the distance between the outer peripheral edges of the feeding elements 12a to 12d and the parasitic elements 13a to 13e is, for example, 2.5 GHz.
In the case of the frequency of z, it is set to 1 mm or less. The dimensions and positions of the parasitic elements 13a to 13e are set to different values depending on the frequency.

On the back side of the dielectric substrate 11, a conductor ground plate 14 is provided. Further, the dielectric substrate 1
The power supply element 12a is divided equally into power supply
The four distributors 16 for distributing the signals to 12d are arranged. This 4
The power output from the distributor 16 is supplied to the feed points 15a to 15d of the feed elements 12a to 12d through the feeder line 17 through the conductor ground plate 14 and the dielectric substrate 11 with equal amplitude and equal phase. In this case, the feeder line 17 and the conductor ground plate 1
4 is insulated so as not to be electrically connected.

In the above configuration, the power equally distributed by the four-way distributor 16 is supplied by the power supply line 17 to each of the power supply elements 12a to 12a-1.
When supplied to the 2d feeding points 15a to 15d, electromagnetic waves of a required frequency are radiated from the respective feeding elements 12a to 12d. The resonance frequency at this time can be obtained from the relative permittivity ε of the dielectric substrate 11 and the thickness of the dielectric substrate 11, and the like, and the feeding points 15a to 15d from the center of the feeding elements 12a to 12d.
Is determined by the length of the feed elements 12a to 12d in the direction toward.

Further, as described above, the feed elements 12a to 12a
When power is supplied to d, the electromagnetic waves of the same frequency as the power feeding elements 12a to 12d are radiated from the parasitic elements 13a to 13e due to the coupling between the power feeding elements 12a to 12d and the parasitic elements 13a to 13e. That is, the adjacent elements, for example, the feeding element 12a and the parasitic element 13a, and the feeding element 12b and the parasitic element 13a are mutually coupled, and an electromagnetic wave having the same frequency as the feeding elements 12a and 12b is radiated from the parasitic element 13a. Is done. Similarly, parasitic elements 13b-
Electromagnetic waves are also emitted from 13d. Also, from the parasitic element 13e located at the center, each of the parasitic elements 13a to 13a
Electromagnetic waves are radiated by mutual coupling between the elements and d. Each of the feed elements 12a to 12d and the parasitic elements 13a to 1
The electromagnetic waves radiated from 3e are combined and act as an array antenna.

According to the above embodiment, the number of antenna elements is 9
The number of feeds is four, and the feed line can be made very simple and the line length can be shortened, so that the line loss is small. Further, since a large number of elements can be arranged even if the number of power supplies is small, a sufficient gain can be obtained.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the second embodiment, a planar antenna and a microstrip line are combined as shown in FIGS. FIG. 3 is a plan view of the antenna,
4 is a sectional view taken along line BB in FIG. 3, and FIG. 5 is a bottom view. Note that, also in the second embodiment, an example is shown in which nine antenna elements are arranged as in the first embodiment.

In the second embodiment, as shown in FIG. 3, four feed elements 12a to 12d are arranged at each corner of the upper surface of the dielectric substrate 11 as in the first embodiment, and Parasitic elements 13a to 13e are arranged between each of the four feed elements 12a to 12d and in the center. And
On the back side of the dielectric substrate 11, a dielectric substrate 31 is laminated via a conductor ground plate 14, as shown in FIG. On the lower surface of the dielectric substrate 31, a feed circuit 33 is formed by a microstrip line 32 as shown in FIG. The power supply circuit 33 includes the microstrip line 32
Is divided into four, and as shown in FIG. 4, power is supplied to the power supply points 15a to 15d of the power supply elements 12a to 12d by the power supply line 34 passing through the dielectric substrate 31, the conductor ground plate 14, and the dielectric substrate 11. I do. In this case, the power supply line 34 and the conductor ground plate 14 are insulated so as not to be electrically connected.

Even when the planar antenna and the microstrip line are combined as described above, the same effects as those of the first embodiment can be obtained, and the configuration can be made extremely thin.

In the first and second embodiments, an array antenna having four feed elements has been described.
Similar effects can be obtained even in an array antenna having two or more feed elements. Also, the case where the element shape is a square has been described, but another shape such as a circle may be used. Further, the overall shape is not limited to a square, but may be another shape.

In the first and second embodiments, the case where the parasitic element is arranged between the feed elements is described. However, one or more parasitic elements are provided around the feed element. The same effects as in the above-described embodiment can be obtained even if the power supply elements are arranged.

[0026]

As described above in detail, according to the present invention, one or a plurality of parasitic elements are arranged between the feeding elements or around the feeding elements, and the feeding element and the parasitic element are arranged. And the elements are mutually coupled, so that the passive element also emits the same frequency of electromagnetic waves as the feed element.
The number of feed elements can be reduced to 以下 or less of the number of antenna elements, the feed line can be extremely simplified, and the line length can be shortened to reduce the line loss. In addition, by disposing a parasitic element between the feeding elements, V.V. S. W. The deterioration of R and the decrease in gain can be prevented, and a sufficient gain can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a plan view of a microstrip array antenna according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB in FIG. 3;

FIG. 5 is a bottom view in the embodiment.

FIG. 6 is a plan view of a conventional microstrip array antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Dielectric substrate 12a-12d Feeding element 13a-13e Parasitic element 14 Conductor ground plate 15a-15d Feeding point 16 4 Divider 17 Feeding line 31 Dielectric substrate 32 Microstrip line 33 Feeding circuit 34 Feeding line

[Procedure amendment]

[Submission date] March 23, 1999 (1999.3.2
3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J021 AA05 AA09 AB06 CA01 FA32 HA05 5J045 AA05 DA09 EA07 FA02 GA01 HA03 MA07

Claims (5)

[Claims] 1. A microstrip array antenna comprising a plurality of antenna elements arranged on the same plane.
The antenna element is a microstrip array antenna, wherein a feed element and a parasitic element are arranged close to each other. 2. The microstrip array antenna according to claim 1, wherein said antenna element is configured by disposing a parasitic element between a feed element and a feed element. 3. The microstrip array antenna according to claim 1, wherein the antenna element is configured by arranging at least one or more parasitic element around a feeding element. 4. The microstrip array antenna according to claim 1, wherein the feed power is distributed to a feed point of each feed element by a distributor. 5. The microstrip array antenna according to claim 1, wherein the feed power is distributed to feed points of each feed element by a microstrip line.