JPH01245706A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To attain impedance matching over a wide frequency range and to feed power to a radiation conductor through a coaxial line by not directly feeding power from the coaxial line to the radiation conductor but feeding power through a feeder circuit comprising a strip line to the radiation conductor. CONSTITUTION:With power supplied from an outer conductor 3 and an inner conductor 4 of a coaxial line, the power is distributed into two by a 90 deg. hybrid 9, a phase of 90 deg. is given and the power is fed to the radiation conductor 1 through feeding conductors 7a, 7b. Thus, the microstrip antenna radiates a circularly polarized radio wave. Moreover, stubs 8a, 8b and 8c, 8d apply impedance matching converting effectively the power fed to the feeding conductors 7a, 7b into the radiation power over a wide frequency band. Thus, the impedance matching element is formed simply by the strip line, the limit in the connecting point of the matching elements is less and the impedance matching over a wide range is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microstrip antenna incorporating a feeding circuit made of a strip line.

[Conventional technology]

3 and 4 are diagrams showing a conventional antenna device disclosed in, for example, Japanese Unexamined Patent Publication No. 61-81001.
The figure is a plan view, and FIG. 4 is a cross-sectional view. In the figure, 2
is a conductor base plate, 1 is a radiation conductor arranged almost parallel to the conductor base plate 2, 3 is an outer conductor of the coaxial line, 4 is an inner conductor of the coaxial line, 5 is a dielectric plate, and 6 is a strip line together with the conductor base plate 2. It is a strip conductor with shorted ends.

Since the conventional microstrip antenna is constructed as described above, radio waves are radiated from the radiation conductor 1 when power is supplied from the inner conductor 4 of the coaxial line. Further, impedance matching is achieved using a strip conductor 6 connected to the inner conductor 4 of the coaxial line as a matching element.

[Problem to be solved by the invention]

As is clear from its configuration, the conventional microstrip antenna as described above has a problem in that impedance matching is limited because the connection points of the impedance matching elements are limited.

This invention was made in order to solve the above-mentioned problems, and it is possible to perform impedance matching over a wide frequency band, and it is also possible to use a microstrip antenna that can be fed with two coaxial lines, such as a microstrip antenna with multi-point feeding. The purpose is to obtain.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured so that power is not directly fed to the radiating conductor from the coaxial line, but is fed to the radiating conductor via a feeding circuit made of a strip line. The strip antenna is configured as follows.

That is, a dielectric plate, a conductive ground plate disposed on one surface of the dielectric plate, a strip conductor disposed on the other surface of the dielectric plate and forming a strip line together with the conductive ground plane, and the dielectric a coaxial line having a radiating conductor arranged substantially parallel to one surface of the body plate at a distance, an outer conductor connected to the conductor ground plate, and an inner conductor connected to one end of the strip conductor; and the strip. A power supply conductor is provided, one end of which is connected to the other end of the conductor, and the other end of which is connected to an appropriate location of the radiation conductor.

(Function) With this configuration, a stub serving as an impedance matching element can be provided at any point in the power feeding circuit, and power can be fed from a single coaxial line to the radiation conductor at multiple points.

〔Example〕

The present invention will be explained below using examples.

FIGS. 1 and 2 are diagrams showing the configuration of a microstrip antenna which is an embodiment of the present invention, with FIG. 1 being a plan view and FIG. 2 being a cross-sectional view thereof.

In the figure, 1 to 5 indicate the same as the above-mentioned conventional example,
7a, 7b are power supply conductors to the radiation conductor, 8a, 8b, 8c
, 8d is a stub for impedance matching, and 9 is a 90 degree hybrid.

10a and 10b are strip conductors that constitute a strip line together with the conductor base plate 2, and stubs 8a, 8b, 8c
, 8d, and the hybrid 9 similarly constitute strip lines with the conductor base plate 2, and a power supply circuit 10 is constituted by these strip lines.

7a and 7b are power supply conductors having one end connected to the ends of the strip conductors 10a and 10b and the other end connected to an appropriate location on the radiation conductor 1.

In the microstrip antenna configured as described above, when power is supplied from the outer conductor 3 and inner conductor 4 of the coaxial line, the power is 2 due to the 90 degree hybrid 9.
The radiation conductor 1 is supplied with power through the power supply conductors 7a and 7b with a phase of 90 degrees. Therefore, this microstrip antenna emits circularly polarized radio waves. Further, the stubs 8a, 8b, 8c, and 8d are the respective power supply conductors 7a.

Impedance matching is performed to effectively convert the power supplied to 7b into radiated power over a wide frequency band.

In this way, since a feed circuit consisting of a strip line is provided between the coaxial line and the feed conductor to the radiation conductor, the impedance matching element can be easily constructed using the strip line, and the connection point of the matching element can be easily configured. There are fewer restrictions and impedance matching over a wide range can be easily achieved. Also, since the radiation conductor and strip line are arranged almost parallel,
-Easy to feed multiple points to the radiating conductor, regardless of whether the power is fed from a single coaxial line.

〔Effect of the invention〕

As described above, according to the present invention, impedance matching over a wide frequency band can be easily performed, and power can be easily supplied to the radiation conductor at multiple points.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the embodiment, FIG. 2 is a cross-sectional view of the same embodiment, FIG. 3 is a plan view of the conventional example, and FIG. 4 is a cross-sectional view of the conventional example. In the figure, 1 is a radiation conductor, 2 is a conductor ground plane, 3 is an outer conductor of a coaxial line, 4 is an inner conductor of a coaxial line, 5 is a dielectric plate, and 7
A and 7b are power supply conductors, and 10 is a power supply circuit consisting of a strip line. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] a dielectric plate, a conductor ground plate disposed on one surface of the dielectric plate, a strip conductor disposed on the other surface of the dielectric plate and forming a strip line together with the conductor ground plane, and the dielectric plate a radiating conductor arranged substantially parallel to one surface of the strip conductor, an outer conductor connected to the conductor ground plate, and an inner conductor connected to one end of the strip conductor;
A microstrip antenna comprising: a feeding conductor having one end connected to the other end of the strip conductor and a feeding conductor having the other end connected to an appropriate location of the radiation conductor.