JPH06334431A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To improve the cross polarized wave characteristic by arranging a linear resistor stretched in the middle of a slot at a front side of the slot in parallel with a long side direction of the slot to allow the linear resistor to absorb a cross polarized wave component. CONSTITUTION:A shape able to propagate an electromagnetic wave in the TE11 mode is adopted for a circular waveguide 1, a horn shape opening 2 is provided on one end and a dielectric plate 5 is provided on the other end to make the opening blind, a ground conductor having a rectangular slot 11 is adopted for a side of the plate 5 facing the waveguide 1 and a feeding circuit pattern 7 is provided in the direction in crossing with the slot 11 and passing through nearly the middle of a long side of the slot 11 is provided on a rear side and a radiation circuit pattern 4 is arranged to a front side of the slot 11. A nearly square conductor plane 8 is provided on a dielectric plate 9 as the pattern 4. The length of an absorbing linear resistor 10 is selected to be longer than a long side of the slot 11 and arranged at almost in the middle of short sides of the slot 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna used as a satellite receiving antenna.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view of a conventional microstrip antenna, (A) is a partially cutaway perspective view, and (B) is a perspective view.
Is a partially enlarged view. In the figure, the vertical direction to the tube axis of the circular waveguide 1 is the Y axis, and the horizontal direction is the X axis (hereinafter the same in FIGS. 1 and 2). A circular waveguide 1 having a shape capable of propagating a TE11 mode electromagnetic wave is used, and a horn-shaped opening 2 is provided at one end to efficiently introduce the electromagnetic wave, and a dielectric plate 5 is provided at the other end. A circular conductor 1 is provided to close the circular waveguide 1, and the side of the dielectric plate 5 facing the circular waveguide 1 is used as a ground conductor 6 having a slot 11 of a substantially rectangular shape. The pattern 7 is provided, and the radiation circuit pattern 4 is arranged on the front surface of the slot 11.

As the radiating circuit pattern 4, for example, a pair of diagonally cut upper and lower left corners of a substantially square shape is used, and it is assumed that a right-handed circularly polarized wave is introduced into the circular waveguide 1.
By adjusting the diagonal cut amount of the radiating circuit pattern 4, the right-handed circularly polarized wave can be converted into the linearly polarized wave having the electric field direction in the Y-axis direction in the radiating circuit pattern 4.
Therefore, if the long side direction of the slot 11 is arranged to be parallel to the X-axis and the length of the slot 11 in the long side direction is set to a length of about a half wavelength of the linearly polarized wave, the linearly polarized wave from the slot 11 is changed. A wave can be output and coupled to the power feeding circuit pattern 7. The power feeding circuit pattern 7 converts the wave into an electric signal, which is input to the LNB input circuit to receive a satellite signal. However, when a left-handed circularly polarized wave which is a cross-polarized wave component is introduced into the circular waveguide 1, the left-handed circularly polarized wave is converted into a linearly polarized wave having an electric field direction in the X-axis direction by the radiation circuit pattern 4, The linearly polarized wave is reflected by the slot 11 and again emitted as a left-handed circularly polarized wave by the radiating circuit pattern 4.

[0004]

A part of the left-handed circularly polarized wave radiated by the radiation circuit pattern 4 is used for the dustproof radome 3.
Is radiated to the outside through
There is a problem that the cross-polarized wave characteristics are deteriorated because the light is reflected by the right-handed circularly polarized light and becomes a right-handed circularly polarized wave and heads for the radiation circuit pattern 4 again. An object of the present invention is to improve the cross polarization characteristic by providing a linear resistor for absorbing the cross polarization component so that the cross polarization component can be absorbed.

[0005]

In the microstrip antenna of the present invention, one surface of the first dielectric plate is a ground conductor having a slot having a substantially rectangular shape, and the other surface intersects with the central portion of the long side of the slot. The feeding circuit pattern provided in the direction, the radiation circuit pattern formed on the surface of the second dielectric plate provided on the front surface of the slot, and the radiation circuit pattern between the first and second dielectric plates are converted by the radiation circuit pattern. And a linear resistor for absorbing a cross-polarized component which is oriented in a direction orthogonal to a desired linearly polarized wave and which is parallel to the long side of the slot and passed to the central part of the slot. To do.

[0006]

As described above, according to the present invention, since the linear resistor is arranged on the front surface of the slot in parallel with the long side direction of the slot and across the central portion of the slot, cross polarization is generated by the linear resistor. The component can be absorbed, and the cross polarization characteristic can be improved.

[0007]

1A and 1B are explanatory views showing a first embodiment of a microstrip antenna of the present invention. FIG. 1A is a partially cutaway perspective view, and FIG. 1B is a partially enlarged view. In the figure, the same components as those shown in FIG. 5 are designated by the same symbols. A circular waveguide 1 having a shape capable of propagating a TE11 mode electromagnetic wave is used, and a horn-shaped opening 2 is provided at one end to efficiently introduce the electromagnetic wave, and a dielectric plate 5 is provided at the other end. The ground conductor 6 is provided and closed, and the side of the dielectric plate 5 facing the circular waveguide 1 is a ground conductor 6 having a substantially rectangular slot 11.
On the back side, face the slot 11 so that it intersects with the slot 11.
Feeding circuit pattern 7 so that it passes through almost the center of the long side of
And the radiation circuit pattern 4 is arranged on the front surface of the slot 11.

As the radiation circuit pattern 4, a dielectric plate 9 is used.
Is formed by providing a substantially square conductor surface 8 and diagonally cutting a pair of diagonally upper and lower left corners of the square to form a hypotenuse, and a center line connecting the centers of the hypotenuses and a side in the longitudinal direction of the slot 11. The insulating surface side of the dielectric plate 9 is attached to the ground conductor 6 in such a manner that the angle formed by is about 45 degrees. The absorbing linear resistor 10 has a length longer than the long side of the slot 11, is arranged parallel to the long side of the slot 11, and passes through the approximate center of the short sides of the slot 11. . The absorbing linear resistor 10 may be formed, for example, by applying a carbon film or the like on the insulating surface side of the dielectric plate 9.

By adjusting the cut-off amount of the oblique side of the radiation circuit pattern 4, the right-handed circularly polarized wave introduced into the circular waveguide 1 is a linearly polarized wave having an electric field direction in the Y-axis direction in the radiation circuit pattern 4. Is converted to. Therefore, the longitudinal direction of the slot 11 is arranged so as to be parallel to the X axis, and the slot 11
If the length in the longitudinal direction is about half the wavelength of the linearly polarized wave, the linearly polarized wave can be output from the slot 11 and coupled to the feeding circuit pattern 7, and the electric power feeding circuit pattern 7 The signal is converted into a signal, and the power feeding circuit pattern 7 and the ground conductor 6 form a microstrip line to transmit the signal and input it to the LNB input circuit so that the satellite signal can be received. When the left-handed circularly polarized wave, which is a cross-polarized wave component, is introduced into the circular waveguide 1, the left-handed circularly polarized wave is converted into a linearly polarized wave having an electric field direction in the X-axis direction by the radiation circuit pattern 4. Since the absorbing linear resistor 10 is arranged in the direction of the X-axis, a current due to the linearly polarized wave flows through the absorbing linear resistor 10 to increase the loss, so that the propagation energy of the linearly polarized wave is increased. Can be damped, and thus
The absorbing linear resistor 10 can absorb left-handed circularly polarized waves that are cross-polarized components, and can improve cross-polarized characteristics as a microstrip antenna.

2A and 2B are explanatory views showing a second embodiment of the microstrip antenna of the present invention. FIG. 2A is a partially cutaway perspective view and FIG. 2B is a partially enlarged view. In the figure, the same parts as those shown in FIG. 1 are shown by the same symbols, and the difference from the embodiment shown in FIG.
The point is that a pair of diagonally upper and lower right corners of a square is obliquely cut to form a hypotenuse, and other configurations are similar to those of the embodiment of FIG. With this configuration, the left-handed circularly polarized wave introduced into the circular waveguide 1 is converted into the linearly polarized wave having the electric field direction in the Y-axis direction by the radiation circuit pattern 14, and the linearly polarized wave from the slot 11 is converted. Can be output to be coupled to the feeding circuit pattern 7, and a signal of left-handed circularly polarized wave can be taken out. The right-handed circularly polarized wave, which is a cross-polarized component, is converted by the radiation circuit pattern 14 into a linearly polarized wave having an electric field direction in the X-axis direction, and the absorbing linear resistor 10 can absorb the same linearly polarized wave. Therefore, it is possible to improve the cross polarization characteristic as the microstrip antenna and receive the left-handed circular polarization.

FIG. 3 is a layout view showing an embodiment in which a plurality of microstrip antennas according to the present invention are used. The radiation element including the radiation circuit pattern 4, the absorption linear resistor 10 and the slot 11 shown in FIG.
A plurality of antennas are provided in the antenna to form a planar antenna, and a feeding circuit pattern 7 arranged in the same manner as in FIG. 1 is provided. A polarized wave signal received from a slot 11 provided in each radiating element is taken out to form a feeding circuit pattern 7. They are connected to each other and connected to the feeding point so that they are in phase with each other by the microstrip line formed by the feeding circuit pattern 7 and the ground conductor 6, and input to the LNB input circuit from the feeding point to receive satellite signals. It is something that is done. Also in this example, the absorbing linear resistor 10 has a length longer than the long side of the slot 11, is parallel to the long side of the slot 11, and passes through the approximate center of the short sides of the slot 11. Because it is arranged as
The cross polarization component can be absorbed by the absorbing linear resistor 10.

FIG. 4 is an explanatory view showing another embodiment of the microstrip antenna of the present invention. In the above-mentioned embodiment, the radiation circuit pattern 4 has a square shape with a pair of diagonally cut diagonally, but this embodiment shows an embodiment in which a circular one is used. The radiating circuit pattern 15 has a shape in which a substantially U-shaped cutout portion 16 is provided on a circular opposing circumference, and the center line connecting the centers of the cutout portions 16 and the long side of the slot 11 are approximately 45 degrees. They are arranged so as to form an angle, and the depth and width of the cutout portion 16 are adjusted so that the right-handed circularly polarized wave is converted into the linearly polarized wave by the radiation circuit pattern 15. Also in this example, the absorbing linear resistor 10 has a length longer than the long side of the slot 11 and is parallel to the long side of the slot 11.
Since they are arranged so as to pass through substantially the centers of their short sides, the cross polarization component can be absorbed by the absorbing linear resistor 10. Other configurations may be the same as those in FIG. 1 or may be the same as those in FIG. 3 and used as a planar antenna. As the shape of the patch element, in addition to the circular shape of this example, a rectangular shape in which the lengths of the diagonal lines are slightly changed or an elliptical shape may be used.

[0013]

As described above, according to the present invention, since the absorption linear resistor can absorb the cross polarization component, it is possible to provide a microstrip antenna having good cross polarization characteristics. It will be possible.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of a microstrip antenna of the present invention, (A) is a partially cutaway perspective view,
(B) is a partially enlarged view.

FIG. 2 is an explanatory view showing a second embodiment of the microstrip antenna of the present invention, (A) is a partially cutaway perspective view,
(B) is a partially enlarged view.

FIG. 3 is a layout view showing an embodiment when a plurality of microstrip antennas according to the present invention are used.

FIG. 4 is an explanatory view showing another embodiment of the microstrip antenna of the present invention.

5A and 5B are explanatory views of a conventional microstrip antenna, in which FIG. 5A is a partially cutaway perspective view and FIG. 5B is a partially enlarged view.

[Explanation of symbols]

 1 Circular Waveguide 2 Opening 3 Radome 4 Radiation Circuit Pattern 5 Dielectric Plate 6 Ground Conductor 7 Feed Circuit Pattern 8 Conductor Surface 9 Dielectric Plate 10 Resistor 11 Slot 14 Radiation Circuit Pattern 15 Radiation Circuit Pattern 16 Notch

Claims (4)

[Claims] 1. A grounding conductor having a substantially rectangular slot on one surface of the first dielectric plate, and a feeding circuit pattern provided on the other surface in a direction intersecting with the central portion of the long side of the slot, and Between the radiation circuit pattern formed on the surface of the second dielectric plate provided on the front surface, and between the first and second dielectric plates, a direction orthogonal to the desired linearly polarized wave converted by the radiation circuit pattern. A microstrip antenna comprising a linear resistor for absorbing cross-polarized components, which is parallel to the long side direction of the slot and passed to the center of the slot. 2. The microstrip antenna according to claim 1, wherein the absorbing linear resistor is made of a carbon film or the like applied to the back surface of the second dielectric plate. 3. The microstrip antenna according to claim 1, wherein a plurality of the microstrip antennas are provided, and the microstrip antennas are connected to a feeding point so that they have the same phase in the feeding circuit pattern. 4. The microstrip antenna according to claim 1, wherein a circular waveguide having an opening through which an electromagnetic wave can be introduced is arranged on a surface of the microstrip antenna on which a radiation circuit pattern is formed. .