JPH0758503A - Feed horn for circularly polarized wave - Google Patents

Abstract

PURPOSE:To provide a feed horn for a circularly polarized wave suitable for miniaturization, with an excellent cross polarized wave characteristic and offering ease of connection to an LNB. CONSTITUTION:The horn is made up of a radio wave output means comprising a dielectric plate 3 and a conductor pattern 4 provided to an opening 1 of a circular waveguide 2, a parallel grating pattern 6 provided to a dielectric plate 5 located at a distance equivalent to a nearly 1/4 wavelength of a radio wave propagated in a circular waveguide 1 from said output means and a radio wave reflection means provided at a distance equivalent to a nearly 1/8 wavelength of a radio wave from the parallel grating pattern 6 and comprising a dielectric plate 7 and a copper foil face 8, and a polarized wave component whose phase is delayed more than that of the other in two orthogonal polarized wave components of a circularly polarized wave introducing to the circular waveguide 2 is reflected in the parallel grating pattern 6 and the polarized wave component whose phase is led is reflected in the copper foil face 8 and converted into a linearly polarized wave at a position of the output means and the converted wave is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave receiver, and more particularly to a circularly polarized feed horn for receiving circularly polarized waves transmitted from a satellite.

[0002]

2. Description of the Prior Art A conventional circularly polarized feed horn is shown in FIG.
As shown in FIG. 2, one end of the circular waveguide 22 is used as the opening 21 and the other end is used as the termination surface 25, and circularly polarized radio waves are efficiently introduced into the circular waveguide 22 through the opening 21 and circularly polarized wave. Used as a wave / linear polarization converter, for example, a circularly polarized wave introduced by a dielectric plate 23 having a length that produces a phase difference of ¼ wavelength is converted into a linearly polarized wave, and the converted linearly polarized wave is obtained. The direction of the electric field of the wave and the direction of the coupling probe 24 are the same, and the probe 24 is arranged at a position of about 1/4 wavelength from the end face 25, and the linearly polarized waves converted by the probe 24 are coupled to each other to generate an electric signal. Converted to LN
I input it to B and received the circularly polarized wave transmitted from the satellite.

[0003]

Therefore, as a circularly polarized feed horn, the length of a circularly polarized wave / linearly polarized wave converter and the length between the terminating surface 25 and the coupling probe 24 are about 1/4. There is a problem that at least the length of the wavelength is required, and it is difficult to reduce the size, and it is necessary to take measures for impedance matching at the joint between the coupling probe 24 and the input circuit of the LNB. The portion becomes complicated, and further, the circular polarization / linear polarization converter provided in the circular waveguide 22 reflects the circular polarization of the reverse rotation with respect to the circular polarization desired to be received, and the opening 21 or the opening. Part 2
1 is again reflected by a portion such as a dust-proof cap provided at the tip of No. 1 and is propagated in the circular waveguide 22 as a circular polarization that rotates in the same direction as the circular polarization desired to be received. There was a problem that the characteristics deteriorate. The present invention relates to a radio wave output means provided in a circular waveguide, a parallel grating pattern provided at a predetermined distance from the output means, and a radio wave provided at a predetermined distance from the parallel grid pattern. With the reflection means, the electric wave is reflected so that the circularly polarized wave is converted into the linearly polarized wave at the position of the electric wave output means, and the converted linearly polarized wave is on the dielectric plate provided as the electric wave output means. Provides a circularly polarized feed horn that is suitable for downsizing and is easily connected to an LNB by connecting directly to a conductor pattern and extracting the desired signal through the conductor pattern. The purpose is to do.

[0004]

A circularly polarized feed horn according to the first invention of the present application is a radio wave output means provided on the opening side of a circular waveguide and a circular guide from the output means. From a parallel grating pattern provided at a distance of about 1/4 wavelength of a radio wave propagating in the wave tube, and a reflection means for reflecting the electric wave provided at a distance of about 1/8 wavelength of the radio wave from the parallel grating pattern. Then, the two polarization components orthogonal to each other of the circular polarization introduced into the same circular waveguide are reflected by the parallel grating pattern for the polarization component with the phase delay, and the phase is reflected. With respect to the polarized wave component of the one that is advancing, it is characterized in that it is reflected by the reflecting means, converted into a linear polarized wave at the position of the output means, and output. In the circularly polarized feed horn of the second invention of the present application, the parallel grating pattern is
It is characterized in that it has a parallel grating pattern having a line width larger than the thickness of the skin with respect to the frequency band used, and has a pattern interval sufficiently narrower than a half wavelength of the radio wave propagating in the circular waveguide.

In the circularly polarized feed horn of the third invention of the present application, the output means is composed of a linear conductor pattern provided on a first dielectric plate inserted inside a circular waveguide, It is characterized in that the conductor pattern and the lines of the parallel lattice pattern are arranged so as to form an angle of about 45 degrees. In the circularly polarized feed horn of the fourth invention of the present application, the output means comprises a rod-shaped pickup probe inserted inside a circular waveguide, and the rod-shaped pickup probe and the lines of the parallel grating pattern are provided. It is characterized in that they are arranged so as to form an angle of about 45 degrees.

The circularly polarized feed horn of the fifth invention of the present application comprises the conductor pattern in which the parallel grating pattern is provided on the second dielectric plate, and the thickness of the second dielectric is the same. The length of the radio wave propagating through the plate is about ¼ wavelength, the reflecting means is a copper foil surface provided on the third dielectric plate, and the thickness of the third dielectric plate is the same. The second dielectric and the third dielectric plate are arranged such that the parallel grating pattern and the copper foil surface are respectively on the inner sides of the circular waveguides, with the length of about 1/8 wavelength of the radio wave propagating inside. And are attached to each other and arranged in the circular waveguide. The circularly polarized feed horn of the sixth invention of the present application uses a double-sided substrate as the third dielectric plate, and provides the parallel grating pattern on the surface of the circular waveguide on the side of the opening, and the surface on the opposite side. It is characterized in that a copper foil surface is provided on.

[0007]

According to the present invention, the circularly polarized wave introduced into the circular waveguide is converted into the linearly polarized wave by the above-mentioned structure, and the circularly polarized wave is provided at the position of about 1/4 wavelength from the output means of the electromagnetic wave. From the parallel grid pattern and about 1 from the parallel grid pattern
/ 8 wavelength reflection means for reflecting radio waves, and the phase of which is delayed with respect to two orthogonal polarization components of circular polarization introduced into the circular waveguide. The polarized wave component is reflected by the parallel grating pattern, and the polarized wave component having the phase advance is reflected by the reflecting means so that a linear polarized wave is formed at the position of the output means. For the circularly polarized wave of the reverse rotation, the polarization component of the phase advance is reflected by the parallel grating pattern, and the polarization component of the phase delay is reflected by the reflection means. Due to the arrangement, both reflected waves have a relationship of opposite phases and are not output as a signal, so that it is possible to improve the cross polarization characteristics, and it is possible to reduce the size of the circular waveguide because the length of the circular waveguide can be shortened. It will be possible.

Further, by using a conductor pattern provided on each dielectric plate for the parallel grating pattern and the reflecting means, and selecting one having a high relative dielectric constant as each dielectric plate, Since the wavelength of the radio wave propagating through can be shortened, the length of the circular waveguide along the tube axis direction can be shortened, and further, the length of the circular waveguide can be shortened, thus enabling miniaturization. Becomes As the output means, a linear conductor pattern provided on a dielectric plate inserted inside a circular waveguide is used, and a signal desired to be received is taken out through the conductor pattern. Connection becomes easy.

[0009]

FIG. 1 is a partially cutaway perspective view of a circularly polarized feed horn showing an embodiment of the present invention. One end of the circular waveguide 2 serves as the opening 1 and the other end serves as the terminating surface 9, and the dielectric plate 3 and the conductor pattern 4 provided on the dielectric plate 3 are sequentially arranged from the opening 1 toward the terminating surface 9. And a dielectric plate 5 having a parallel lattice pattern 6 on one side,
A dielectric plate 7 having a copper foil surface 8 on one surface is arranged. In addition, in FIG. 1, 10 and 11 show notched lines.

FIG. 2 is a partially cutaway side view of FIG.
The dielectric plate 3 is oriented perpendicular to the tube axis of the circular waveguide 2, and is inserted and arranged between the opening 1 side of the circular waveguide 2 and the end face 9 side. One end of the linear conductor pattern 4 provided on the surface of is directed toward the central axis of the circular waveguide 2, and the other end is drawn out of the circular waveguide 2,
A signal can be output from the conductor pattern 4.
As the dielectric plate 5, a cylindrical one having a diameter smaller than the inner diameter of the circular waveguide 2 is used, and the distance between the conductor pattern 4 and the parallel lattice pattern 6 provided on one side of the dielectric plate 5 is the same. The thickness of the plate 5 is set to be about ¼ wavelength of the radio wave propagating through the plate 5, so that the radio wave reflected by the parallel grating pattern 6 can be efficiently coupled to the conductor pattern 4.

The thickness of the dielectric plate 7 is the parallel lattice pattern 6
And the distance to the copper foil surface 8 provided on one side of the dielectric plate 7 is set to be about 1/8 wavelength of the radio wave propagating through the dielectric plate 7, and the radio wave passing through the parallel grating pattern 6 is So that it can be reflected, and the dielectric plate 5 and the dielectric plate 7 are bonded together,
It is fixed in the circular waveguide 2 while being in contact with the dielectric plate 3. If the dielectric plates 5 and 7 having a high relative permittivity are selected and used, the wavelength of the radio wave propagating through the dielectric plates can be shortened. Therefore, the thickness of the dielectric plates 5 and 7 can be reduced. Therefore, it is possible to reduce the length of the circular waveguide 2 in the tube axis direction and reduce the size.

FIG. 3 is a partially cutaway sectional view taken along the line AA of FIG. In the parallel grating pattern 6, the pattern interval (the interval between the center lines of the patterns) D is made sufficiently narrower than the half-wave length of the radio wave propagating through the dielectric plate 5, and the line width d of the conductor pattern is set to the circular polarization feed. The horn has a shape in which a plurality of parallel conductor patterns are provided to be larger than the skin thickness for the frequency band used. The thickness of the epidermis is generally defined as the thickness of the skin current flowing,
For example, if copper is used as the conductor pattern, 12G
The skin thickness for a radio wave of Hz is about 1 μm, and the line width d is set to a value exceeding 1 μm, which is selected and determined depending on mechanical strength or workability. FIG. 3 shows an arrangement for receiving left-handed circularly polarized waves. The angle formed by the conductor pattern of the parallel grating pattern 6 and the conductor pattern 4 for picking up the radio wave is 45 degrees. It is arranged so that it goes up to the left.

FIG. 4 is an explanatory diagram of circularly polarized waves, and the traveling direction of radio waves is from the front to the back of the paper. If a left-handed circularly polarized wave is introduced into the circular waveguide 2, the electric field vector E of the left-handed circularly polarized wave is expressed by two orthogonal linearly polarized components in the X-axis and Y-axis directions, Ex = Ecosωt · ex and Ey = Ec
It can be decomposed into os (ωt + π / 2) · ey. Here, ex and ey represent unit vectors in the X-axis and Y-axis directions, respectively. Therefore, the linearly polarized wave component is E
The phase of Ey is advanced by 90 degrees from x and propagates in the circular waveguide 2.

The conductor pattern of the parallel grid pattern 6 of FIG. 3 is parallel to the direction of the electric field of the linearly polarized wave component Ex in the X-axis direction, and the pattern interval D is sufficiently longer than the half wavelength of the radio wave propagating through the dielectric plate 5. Since the line width d is set to a value exceeding the skin thickness, the linear polarization component Ex in the X-axis direction is reflected by the parallel grating pattern 6 and the direction of the electric field of the linear polarization component Ey in the Y-axis direction. Has a direction crossing the conductor pattern of the parallel lattice pattern 6, and therefore propagates through the parallel lattice pattern 6. The linearly polarized wave component Ey reaches the copper foil surface 8 provided on one surface of the dielectric plate 7 at a distance of about 1/8 wavelength from the parallel grating pattern 6 and is reflected by the copper foil surface 8.

Therefore, the linear polarization component Ex reflected by the parallel grating pattern 6 and the linear polarization component Ey reflected by the copper foil surface 8
The phase relationship of the linear polarization component Ey becomes the same phase because the propagation path of the linear polarization component Ey is longer than the linear polarization component Ex by ¼ wavelength, and a combination of both linear polarization components has two X-axis and Y-axis components.
It can be converted into a linearly polarized wave having the electric field vector E at the dividing angle. Since the pickup conductor pattern 4 is arranged so as to be parallel to the direction of the converted linearly polarized electric field, the linearly polarized electric field is coupled to the conductor pattern 4 and converted into an electric signal, 4 outputs the signal from the circular waveguide 2, and a ground conductor is provided outside the circular waveguide 2 on the back surface of the dielectric plate 3 to form a conductor pattern 4 and a microstrip line. Transmitted L
The input signal is input to the NB so that satellite signals can be received.

In FIG. 4, assuming that a right-handed circular polarization, which is a cross-polarized wave with respect to the left-handed circular polarization desired to be received, is introduced into the circular waveguide 2, the electric field vector E of the right-handed circular polarization is two. The linearly polarized components in the X-axis and Y-axis directions that are orthogonal to each other are, as shown in parentheses, Ex = Ecosωt · ex and Ey = Ec
It can be decomposed into os (ωt−π / 2) · ey. Here, ex and ey represent unit vectors in the X-axis and Y-axis directions, respectively. Therefore, the linearly polarized wave component is E
Ex propagates through the circular waveguide 2 in a state in which the phase is 90 degrees ahead of y. Since the polarized wave component Ex having the advanced phase is reflected by the parallel grating pattern 6 and the polarized wave component Ey having the delayed phase is reflected by the copper foil surface 8, both reflected waves are Since there is a relationship of opposite phases, and therefore the combined signal is not output as a canceling signal, it is possible to improve the cross polarization characteristic.

FIG. 5 is an explanatory view of a circularly polarized feed horn showing another embodiment of the present invention, showing an example for receiving right-handed circularly polarized wave. In FIG. 1, only the direction of the parallel grid pattern 6 provided on the dielectric plate 5 is changed and the other configurations are made the same to form a parallel grid pattern 15 as shown in FIG. 5, and the conductor pattern of the parallel grid pattern 15 and the radio wave pickup. The angle formed with the conductor pattern 4 for use is 45 degrees, and the conductor pattern of the parallel lattice pattern 15 is arranged so as to rise to the right. For two orthogonal polarization components Ex and Ey of right-handed circularly polarized waves introduced into the circular waveguide 2,
The polarized wave component Ey having a phase delay is reflected by the parallel grating pattern 15, and the polarized wave component Ex having a phase advance is reflected by the copper foil surface 8 to be synthesized. For the left-handed circularly polarized wave of the reverse rotation, the polarized wave component Ey having the advanced phase is reflected by the parallel grating pattern 15 and the polarized wave having the delayed phase is polarized. Since the arrangement is such that the wave component Ex is reflected by the copper foil surface 8, both reflected waves have a relationship of opposite phases and are not output as a canceling signal due to synthesis, so that cross polarization characteristics can be improved. Becomes

The depth of insertion of the pickup conductor pattern 4 into the circular waveguide 2 is adjusted so that the electric wave converted from the circularly polarized wave to the linearly polarized wave can be efficiently coupled to the conductor pattern 4. decide. The conductor pattern 4 may be provided on the back side of the dielectric plate 3. Alternatively, instead of using the conductor pattern 4, a rod-shaped pickup probe having the same arrangement is used, and an electric signal extracted through the probe is used. May be input to the input circuit of the LNB. It suffices if the parallel grating pattern 6 is located at a position of about ¼ wavelength of the radio wave propagating in the circular waveguide 2 from the conductor pattern 4, and the copper foil surface 8 is from the parallel grating pattern 6 to the circular waveguide 2. It only needs to be at a position of about 1/8 wavelength of the radio wave propagating inside, and by using the copper foil surface provided on one side of each dielectric plate, it becomes easy to set a predetermined interval,
The processing can be facilitated, and the length of the circular waveguide along the tube axis direction can be shortened.

Instead of using the copper foil surface 8 by removing the dielectric plates 5 and 7, the end surface 9 of the circular waveguide 2 is made to reflect the radio wave, and the parallel grating pattern 6 is made of a single metal. A ring may be used. Alternatively,
The dielectric plate 7 having copper foils on both sides is used, the parallel lattice pattern 6 is provided on one surface, the entire surface is made of copper foil surface 8, and the dielectric plate 5 is obtained by removing the parallel lattice pattern 6. You may use it.

[0020]

As described above, according to the present invention,
It is possible to provide a circularly polarized feed horn which is suitable for downsizing and which has an improved cross polarization characteristic and which can be easily connected to an LNB.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a circularly polarized feed horn showing an embodiment of the present invention.

FIG. 2 is a partially cutaway side view of FIG.

FIG. 3 is a partially cutaway sectional view taken along the line AA in FIG.

FIG. 4 is an explanatory diagram of circular polarization.

FIG. 5 is an explanatory view of a circularly polarized feed horn showing another embodiment of the present invention.

FIG. 6 is a partially cutaway perspective view of a circularly polarized feed horn showing a conventional example.

[Explanation of symbols]

 1 Opening 2 Circular Waveguide 3 Dielectric Plate 4 Conductor Pattern 5 Dielectric Plate 6 Parallel Lattice Pattern 7 Dielectric Plate 8 Copper Foil Surface 9 End Face 10 Notch Line 11 Notch Line 15 Parallel Lattice Pattern 21 Opening 22 Circular waveguide 23 Dielectric plate 24 Probe 25 End surface

Claims (6)

[Claims] 1. A radio wave output means provided on the opening side of the circular waveguide and a parallel provided at a distance of about ¼ wavelength of the radio wave propagating through the circular waveguide from the output means. Approximately 1/8 of the radio wave from the grid pattern and the parallel grid pattern
A circular polarized wave introduced into the circular waveguide is orthogonal to each other, and is composed of a reflection means provided at a distance of the wavelength for reflecting an electric wave.
With respect to the two polarization components, the one having a phase delay is reflected by the parallel grating pattern, and the polarization component having a phase advance is reflected by the reflecting means. A circularly polarized feed horn which is reflected and converted into a linearly polarized wave at the position of the output means for output. 2. The parallel grating pattern has a parallel grating pattern having a line width greater than the thickness of the skin with respect to the frequency band used, and the pattern spacing is sufficiently narrower than the half wavelength of the radio wave propagating in the circular waveguide. The circularly polarized feed horn according to claim 1, which comprises: 3. The output means comprises a linear conductor pattern provided on a first dielectric plate inserted inside a circular waveguide, and the conductor pattern and the lines of the parallel lattice pattern are approximately The feed horn for circularly polarized waves according to claim 1 or 2, wherein the feed horn is arranged so as to form an angle of 45 degrees. 4. The output means comprises a rod-shaped pickup probe inserted inside a circular waveguide, and the rod-shaped pickup probe and the lines of the parallel grating pattern are arranged so as to form an angle of about 45 degrees. The feed horn for circularly polarized wave according to claim 1 or 2, characterized in that. 5. The parallel lattice pattern comprises a conductor pattern provided on a second dielectric plate, and the thickness of the second dielectric plate is about 1/4 wavelength of a radio wave propagating in the dielectric plate. The length of the reflecting means is a copper foil surface provided on the third dielectric plate, and the thickness of the third dielectric plate is about 1/8 wavelength of a radio wave propagating in the dielectric plate. As a result, the parallel dielectric pattern and the copper foil surface are located on the inner side of the circular waveguide, and the second dielectric and the third dielectric plate are attached to each other and arranged in the circular waveguide. The feed horn for circularly polarized waves according to claim 1, 2, 3 or 4. 6. A double-sided substrate is used as the third dielectric plate, the parallel grating pattern is provided on the surface of the circular waveguide on the opening side, and a copper foil surface is provided on the opposite surface. The feed horn for circularly polarized wave according to claim 5.