JPH0522028A - Antenna device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Regarding the structure of the microstrip antenna,
The purpose is to obtain a desired radiation pattern and high gain. A shield 4 composed of a conductor plate or a conductor rod is provided at a position approximately midway between the microstrip antenna elements of a plurality of microstrip antenna elements 1 arranged on the same plane of a dielectric substrate 2.
It is configured by being provided almost perpendicular to the plane on which the are arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device having a plurality of microstrip antenna elements arranged on a plane, and more particularly to an antenna having a structure capable of improving a radiation pattern, a gain and a voltage standing wave ratio. Related to the device.

[0002]

2. Description of the Related Art As an example of this type of conventional antenna, for example, the one shown in the literature, "B-96" In-vehicle phased array antenna for satellite communication "in the National Conference of the Institute of Electronics, Information and Communication Engineers, 1990" is used. is there. FIG. 8 is a diagram showing the antenna device shown in the above-mentioned paper, in which 51 is a microstrip antenna element, 52 is a dielectric substrate which constitutes the antenna device by arranging the microstrip antenna elements on the same plane, Reference numeral 53 represents a feeding circuit for feeding and exciting each microstrip antenna element 51 with a set desired amplitude.

In FIG. 1, each microstrip antenna element 51 of the antenna device is fed with a desired excitation amplitude phase by a feeding circuit 53, and a desired radiation pattern and a practical radiation pattern are obtained by the principle of so-called array antenna directivity synthesis. , Gain can be obtained. Since each microstrip antenna element is designed to match the impedance of each feeding circuit, it is possible to radiate radio wave energy with a certain efficiency.
Also, when this array antenna is used for reception, radio waves can be received with a radiation pattern similar to that at the time of transmission and a practical gain due to the reversibility of the antenna.

[0004]

The conventional antenna device configured as described above radiates a desired radio wave into the space during actual use, and at the same time, the microstrip antenna element and another microstrip antenna element are combined. The active impedance of each microstrip antenna element greatly changes as compared with the self-impedance of a single unit due to electromagnetic coupling existing between the space or the surface of the dielectric substrate 52, so that the active impedance of each microstrip antenna element is different from that of the feeding circuit. There is a problem in that a mismatch occurs, which increases the reflected power of the antenna and reduces the efficiency. Also,
Since the excitation amplitude phase set for each microstrip antenna element changes from a desired value, it is difficult to obtain a desired radiation pattern, and as a result, there is a problem that the gain decreases.

The present invention has been made to solve the above problems, and excites each microstrip antenna element with a desired excitation distribution that has been set to achieve good matching with a power supply circuit. The desired radiation pattern,
An object is to provide an antenna device that can easily obtain high gain.

[0006]

According to the invention, the above mentioned objects are achieved by means of the patent claims. That is, according to the invention of claim 1, in an antenna device configured by arranging a plurality of microstrip antenna elements on the same plane of a dielectric substrate, at least one microstrip antenna element and at least one adjacent to the microstrip antenna element. A shield plate made of a conductor is placed at a position substantially equidistant from each of the two microstrip antenna elements corresponding to one microstrip antenna element, and the shield plate is erected substantially perpendicular to the plane in which the microstrip antenna elements are arranged. The installed antenna device.

Further, the invention of claim 2 corresponds to the shielding plate made of the above conductor, and is one in which a plurality of conductive rod-shaped members are planted to form a shielding body.

The shield plate made of the conductor or the shield plate made of a conductive rod-shaped member is, for example, at the intersection with the line segment connecting the centers of the corresponding two microstrip antenna elements, with respect to the line segment. It is formed so as to have planes or curved surfaces that are substantially orthogonal to each other.

[0009]

In the antenna device according to the present invention, the electromagnetic coupling between the microstrip antenna elements is achieved by a shield plate made of a conductor provided on the dielectric substrate between the microstrip antenna elements or a plurality of conductive rod-shaped members. Since it suppresses, it is possible to reduce the difference between the active impedance and the self impedance of the microstrip antenna element, so the radiation pattern of the antenna device,
Gain, voltage standing wave ratio (hereinafter referred to as VSWR), etc. can be improved to desired characteristics. Hereinafter, the operation and the like of the present invention will be described in detail based on Examples.

[0010]

FIG. 1 is a diagram showing a first embodiment of the present invention, in which (a) is a plan view, (b) is a sectional view taken along line AA of (a), and 1 is A microstrip element, 2 is a dielectric, 3 is a feeding circuit, and 4 is a shield plate made of a conductor.

2A and 2B are views showing a second embodiment of the present invention, in which FIG. 2A is a plan view, FIG. 2B is a sectional view taken along the line AA of FIG. 3 to 3 are the same as in the case of FIG. 1, and 4a represents a shielding plate.

FIG. 9 is a diagram showing an example of a conventional antenna device, (a) is a plan view and (b) is a sectional view taken along the line AA of (a). Is the same as in the case of FIG. This figure is provided to explain the present invention in comparison with the conventional case.

An embodiment of the present invention will be described below with reference to FIGS. In the conventional antenna device shown in FIG. 9, the electric wave fed from the feeding circuit 3 to each microstrip antenna element 1 is radiated into space, but other than the antenna device which is apart from only a half wavelength to a few wavelengths. By coupling to the microstrip antenna element of, and by conversely coupling the radio waves radiated from other microstrip antenna elements, the active impedance changes without being able to maintain the self-impedance when alone,
As a result, VSWR is deteriorated to reduce efficiency, or the excitation amplitude / phase distribution of each microstrip antenna element 1 in the antenna device set by the feeding circuit 3 is changed from a desired distribution, resulting in a radiation pattern and a gain. Also changes from the desired value. Therefore, as shown in FIG. 2, when a shield plate 4a is provided between the microstrip antenna elements 1 to suppress electromagnetic coupling in space,
The active impedance can be almost the same as the self impedance.

FIG. 10 shows the active impedance of the center microstrip antenna element 1 when seven microstrip antenna elements 1 are fed in the same amplitude and phase in the conventional antenna apparatus shown in FIG. It is a figure which shows the measured value of self-impedance of. In the figure, the solid line B shows the self impedance, and the dotted line C shows the active impedance. Also,
FIG. 11 is a diagram showing the actual measured value D of the VSWR alone and the actual measured value E of the active VSWR of the central microstrip antenna element in the conventional antenna device shown in FIG.

FIG. 3 shows the antenna device of the second embodiment of the present invention shown in FIG. 2, in which the seven microstrip antenna elements 1 are fed at the same amplitude and the same phase. It is a figure which shows the active impedance and the measured value of the self-impedance at the time of supplying electric power independently. In the figure, the solid line F shows the self impedance, and the dotted line G shows the active impedance. The difference between the two is very small, and it can be seen that the conductor wall 4 improves the active impedance characteristic.

FIG. 4 is a diagram showing the actual measured value H of the VSWR alone and the actual measured value I of the active VSWR of the central microstrip antenna element 1 in FIG. Microstrip antenna element 1 in this case is circular, the height of the shielding plate 4a is 10 mm, the frequency is 2.6GH _z band. In the above embodiment, the shield plate 4a is formed in a hexagonal shape around the center of the microstrip antenna element and arranged. However, as in the third embodiment shown in FIG. 5, the shield plate 4b is disposed. It goes without saying that the same effect can be obtained by forming the circular shape.

In the above embodiment, the circular microstrip antenna element is used as the antenna element.
Even if a microstrip antenna element having a rectangular shape or an arbitrary shape as in the fourth embodiment shown in FIG. 6 is used and the shielding plate 4C is provided, the same effect can be obtained.

FIG. 7 is a diagram showing a fifth embodiment of the present invention. In the figure, reference numeral 5 is a shield composed of a plurality of conductor rods standing upright on the dielectric substrate 2. Since the shield 5 is formed by disposing a plurality of conductor rod-shaped members so as to be parallel to each other between the microstrip antenna elements to form a shield, a space between the microstrip antenna element and another microstrip antenna element is formed. The electromagnetic coupling of the space is suppressed, and the same effect as that of the shielding plates 4 and 4a to 4c of the above-described embodiment is obtained. (In each of FIGS. 5 to 7, (a) is a plan view and (b) is a cross-sectional view taken along line AA of (a) in FIGS. 5 to 7).

In the above embodiments, the case where the shape of the shield made of the shield plate or the conductive rod-shaped member is hexagonal or circular is described, but the shape is not limited to such a shape, and it is not limited to such a shape. The shape may be arbitrary according to the arrangement of the strip antenna elements. Further, it is needless to say that the shielding plate does not have to be plate-shaped, and the same effect can be obtained even if the shielding plate is mesh-shaped.

[0020]

As described above, according to the present invention,
In an antenna device configured by arranging a plurality of microstrip antenna elements on the same plane of a dielectric substrate,
By providing a shield plate with a simple structure or a shield formed by a rod-shaped conductor member, electromagnetic coupling between microstrip antenna elements is reduced, and the difference between active impedance and self impedance is reduced. Therefore, there is an advantage that a high gain antenna device having a desired radiation pattern can be easily realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing actually measured values of active impedance and self impedance of an antenna element according to a second embodiment.

FIG. 4 shows the V of a single antenna element in the center of the second embodiment.
It is a figure which shows the measured value of SWR and active VSWR.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a fifth embodiment of the present invention.

FIG. 8 is a diagram showing an example of a conventional antenna device.

FIG. 9 is a diagram showing an example of a conventional antenna device.

FIG. 10 is a diagram showing actually measured values of active impedance and self impedance of an antenna element of a conventional antenna device.

FIG. 11 is a diagram showing actual measured values of VSWR and active VSWR of a single antenna element of a conventional antenna device.

[Explanation of symbols]

1 Microstrip antenna element 2 dielectric 3 power supply circuit 4 Shield 5 Shield

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Mizutame             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Uji Kobayashi             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd.

Claims (2)

[Claims] 1. An antenna device comprising a plurality of microstrip antenna elements arranged on the same plane of a dielectric substrate, wherein at least one microstrip antenna element and at least one microstrip adjacent to the microstrip antenna element. At a position approximately equidistant from both microstrip antenna elements between the antenna element,
An antenna device characterized in that a shielding plate made of a conductor is erected substantially perpendicular to a plane on which microstrip antenna elements are arranged. 2. An antenna device comprising a plurality of microstrip antenna elements arranged on the same plane of a dielectric substrate, wherein at least one microstrip antenna element and at least one microstrip adjacent to the microstrip antenna element. A characteristic that a plurality of conductive rod-shaped members are planted substantially perpendicular to the planes where the microstrip antenna elements are arranged at positions approximately equidistant from both the microstrip antenna elements. And antenna device.