JPH06120702A - Coaxial waveguide converter - Google Patents

Abstract

PURPOSE:To obtain a high cross polarized wave identification level by providing mutually orthogonally intersecting two rectangular waveguides for intersecting orthogonally with an input waveguide, bending those rectangular waveguides to an inverse direction at 45 deg., and projecting probes in those waveguides. CONSTITUTION:A horizontal polarized wave 1 and a vertical polarized wave 2 in a circular waveguide 5 are respectively led to a rectangular waveguide 6 and a rectangular waveguide 7 by reflecting bars 8 and 9. The polarized waves 1 and 2 in the waveguides 6 and 7 are bent at 45 deg., and detected by probes 3 and 4 provided on a circuit board 10. The waveguides 6 and 7 are fixed by shifting the position to the axial direction of the waveguide 5 almost at the same dimension as the longitudinal sides of the waveguides 6 and 7. Thus, the waveguides of the polarized waves 1 and 2 can be independently provided, and the high cross polarized wave identification level can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in, for example, an input section of a converter for an antenna for receiving satellite broadcasting or satellite communication, and is a coaxial type for receiving horizontal polarized waves and vertical polarized waves orthogonal to each other with a high degree of separation. The present invention relates to a waveguide conversion unit.

[0002]

2. Description of the Related Art Conventionally, an outdoor converter for receiving satellite broadcasting, which is mounted on an antenna for receiving two types of independent linearly polarized waves (horizontal polarized wave and vertical polarized wave) orthogonal to each other, is known. Uses a coaxial-to-waveguide converter.

FIG. 7 is a partially cutaway sectional perspective view showing the internal structure of an example of a coaxial-waveguide converter used in a conventional satellite broadcast receiving outdoor converter. In the figure, this coaxial-to-waveguide converter comprises, for example, a circular waveguide 101 and a circular waveguide 10 connected to a horn (not shown).
A first microstrip circuit board (hereinafter referred to as a circuit board) 102 attached at a predetermined position on the outer periphery of the first substrate 1, and formed on the circuit board 102 so as to project inward through an opening of a circular waveguide 101. The first probe 105
And a short rod 104 which is a short-circuit terminal provided inside the circular waveguide 101 at a distance of a quarter wavelength downward from the position where the first probe 105 is attached. Further, the second probe 106 formed so as to project downward from the first probe 105 at an interval of about a half wavelength into the circular waveguide 101 and the second probe 106 are circular waveguides. The second circuit board 103, which is installed through the opening of the circular waveguide 101 and is attached to the outer peripheral portion of the circular waveguide 101, is spaced downward from the second probe 106 by a quarter wavelength. And a short plate 107 which is a short-circuit terminal attached.

The first probe 105 and the short rod 104
Are installed such that their extending directions are substantially the same. First probe 105 and second probe 1
06 are installed such that their extending directions are orthogonal to each other. The first probe 105 is for detecting the horizontal polarized wave 1, and the second probe 106 is for detecting the vertical polarized wave 2. Short stick 10
Reference numeral 4 is for reflecting the horizontal polarized wave 1 so that the first probe 105 can detect it.
Reference numeral 7 is for reflecting the vertically polarized wave 2 and causing the second probe 106 to detect it.

Generally, two probes are required to receive two kinds of linearly polarized waves which are orthogonal to each other by a single waveguide. Each probe receives a signal that has a plane of polarization parallel to the probe. In order to suppress the interference of signals having polarization planes other than the polarization plane parallel to the probe and improve cross polarization discrimination characteristics (Cross polarization discrimination), as shown in FIG. It is necessary to make the first probe 105 and the second probe 106 of 101 orthogonal to each other and to separate, for example, a half wavelength interval in the axial direction. In addition, the waveguide input VSWR (voltag
In order to improve the e standing wave ratio) and suppress the conversion loss between the first probe 105 and the second probe 106 in a wide band, as shown in FIG.
05 and the short rod 104, and the second probe 106 and the short plate 107, the distance 1 /
It is necessary to make an interval of four wavelengths.

FIG. 8 is a partially cutaway sectional perspective view showing the internal structure of another example of the conventional coaxial-waveguide converter. In the figure, this coaxial-waveguide converter is a circular waveguide 2
01, a circuit board 202 attached to a predetermined position on the outer circumference of the circular waveguide 201, and a first probe 203 formed on the circuit board 202 so as to project into the circular waveguide 201. A second probe 204 attached to the circuit board 202 and formed to project inside the circular waveguide 201 in a direction orthogonal to the first probe 203 on the same plane, and the first probe 203 and the second probe. A short plate 205 is attached downward from 204 at a distance of ¼ wavelength. In this coaxial-waveguide converter, the first probe 203 and the second probe 204 are formed on the same plane. By thus mounting the first probe 203 and the second probe 204 on the same plane, it is possible to reduce the size of the device.

[0007]

As described above, in the structure of the conventional coaxial-waveguide converter shown in FIG. 7, the signal received by the first probe 105 and the signal received by the second probe 106 are received. In order to improve the cross polarization discrimination characteristic by suppressing the interference with the signal to be generated, the first probe 105 and the second probe 106 are separated by about a half wavelength.

However, in such a structure, the first
Since the first probe 105 and the second probe 106 are not on the same plane, the first probe 105 can be mounted on a single circuit board.
It was difficult to directly connect both and the second probe 106. As a result, as shown in FIG. 7, two circuit boards, the first circuit board 102 and the second circuit board 103, were required. As a result, the number of parts is increased and the manufacturing process is complicated, so that the cost cannot be reduced and the mass productivity cannot be improved.

Further, in the coaxial-waveguide converter of another example shown in FIG. 8, since the first probe 203 and the second probe 204 are on the same plane as described above, Although the size can be reduced, the cost can be reduced, and the mass productivity can be improved, since the first probe 203 and the second probe 204 are on the same plane, the polarization planes other than the polarization planes to be received are different. With a signal (electric field) interferes with. As a result, there is a problem that the cross polarization discrimination characteristic deteriorates.

An object of the present invention is to provide a coaxial-waveguide converter in which the first linearly polarized wave and the second linearly polarized wave orthogonal to the first linearly polarized wave are independent of each other, and on the same circuit board. The first probe and the second probe are provided to obtain a high degree of cross polarization discrimination.

[0011]

SUMMARY OF THE INVENTION The coaxial-to-waveguide converter of the present invention is provided with two rectangular waveguides orthogonal to the input waveguide and further orthogonal to each other, and these rectangular waveguides are opposite to each other. The rectangular waveguide is bent at 45 degrees, and one side of the rectangular waveguide is constituted by the ground plane of the circuit board, and two probes provided on the circuit board are projected into the inside of each rectangular waveguide. Further, by bending at least one of the two rectangular waveguides whose one side is constituted by the ground plane of the circuit board in a direction substantially perpendicular to the axial direction of the input waveguide, the two probes are connected to the axis of the input waveguide. It is arranged at a position that is substantially axisymmetric.

[0012]

Operation: The input waveguide has first and second portions orthogonal to each other.
Linearly polarized waves (horizontal polarized wave and vertical polarized wave) are introduced, respectively guided separately to the first and second rectangular waveguides connected so as to be orthogonal to each other, and further bent in opposite directions by 45 degrees. Therefore, the first and second linearly polarized waves are electric fields (polarized waves) in the same direction. Therefore, the first and second linearly polarized waves can be detected by the first and second probes provided on the same circuit board in the same direction.

[0013]

1 (a) and 1 (b) are a horizontal sectional view and a vertical sectional view, respectively, of a first embodiment of the present invention. Although the input waveguide can be either circular or rectangular, this embodiment describes the case of a circular input waveguide.

In FIGS. 1 (a) and 1 (b), a circular waveguide 5 connected to a horn (not shown) for receiving a signal, and a first integrally connected orthogonally thereto. For example, a rectangular waveguide 6 and a circular waveguide 5 which is spaced apart from the first rectangular waveguide 6 by a predetermined distance and is orthogonal to the first rectangular waveguide 6 and the circular waveguide 5 The second rectangular waveguide 7 is connected to the circular waveguide 5, and the circular waveguide 5 is provided with the reflecting rods 8 and 9 at a certain distance. The reflecting rod 8 is provided parallel to the electric field of the horizontal polarized wave in order to reflect the first linear polarized wave, for example, the horizontal polarized wave 1.
The reflected horizontal polarized wave 1 is guided to the first rectangular waveguide 6. The second linearly polarized wave, for example, the vertically polarized wave 2 is reflected by the reflecting rod 9 parallel to the electric field and guided to the second rectangular waveguide 7.

The horizontally polarized wave 1 in the first rectangular waveguide 6 is 45
It is bent once and is detected by the first probe 3 provided on the circuit board 10 forming one side of the first rectangular waveguide 6. The vertically polarized wave in the second rectangular waveguide 7 is bent by 45 degrees in the opposite direction to the horizontally polarized wave 1, and is also applied to the circuit board 10 that constitutes one side of the second rectangular waveguide 7. It is detected by the second probe 4 provided.

Here, the rectangular waveguides 6 and 7 are made of the same material as the circular waveguide 5 and are the chassis 12 of the converter.
1 and a part of the ground surface on the back surface of the circuit board 10 attached to the chassis 12, and a cover 11 (shown by a chain double-dashed line in FIG. 1B).
As shown in (b), the positions of the rectangular waveguides 6 and 7 are shifted in the axial direction of the circular waveguide 5. Here, the dimensions of the long sides of the rectangular waveguides 6 and 7 are shifted by approximately the same amount, but if this dimension becomes smaller, the degree of separation between horizontal polarization and vertical polarization (cross polarization discrimination) deteriorates.

The reflecting rod 8 or 9 is provided with a cover 11
The screw used when the is attached to the circular waveguide 5 and the chassis 12 can be used as a reflecting rod.

2 (a) and 2 (b) respectively show the second
FIG. 3 is a horizontal sectional view and a vertical sectional view of the embodiment of FIG. Figure 2 (b)
In, the cover 11 is indicated by a chain double-dashed line. Figure 1
The difference from the embodiments of (a) and (b) is that after the first rectangular waveguide 6 is bent in the direction of 45 degrees, the circuit board 10
The rectangular waveguide constituted by the ground surface on the back surface of the and the cover 11 is further bent at a right angle to the axial direction of the circular waveguide 5,
The probe 3 is provided at a position substantially symmetrical to the position of the second probe 4 with respect to the axis of the circular waveguide 5.

12CH used for satellite broadcasting and satellite communication
In the z-band converter circuit, the planar arrangement of signal lines and components has a great influence on the performance. Therefore, in the case of having two similar amplifier circuits, such as a converter for horizontal and vertical polarization, it is better to make the two circuits similar or symmetrical in terms of placement.
It is also excellent in terms of separation degree (cross polarization discrimination degree) and stability of circuit operation.

In the configurations of FIGS. 2 (a) and 2 (b), the two amplifier circuits of the converter connected to each probe can be arranged in a similar or symmetrical manner.

FIG. 3 is a conversion loss characteristic (shown by a solid line A) of the first probe of the coaxial-waveguide converter according to the present invention shown in FIGS. 1 (a) and 1 (b), and is shown in FIG. It is a characteristic view which compared the conversion loss characteristic (shown with the broken line B) of the 1st probe of the conventional coaxial-waveguide converter. 4 is shown in FIG.
The conversion loss characteristics (shown by the solid line A) of the second probe of the coaxial-waveguide converter according to the present invention shown in (a) and (b), and the conventional coaxial-waveguide converter shown in FIG. 5 is a characteristic diagram comparing the conversion loss characteristics (shown by a broken line B) of the second probe of FIG.

FIG. 5 is a cross polarization discrimination characteristic (shown by a solid line A) of the first probe of the coaxial-waveguide converter according to the present invention shown in FIGS. 1 (a) and 1 (b), and FIG. FIG. 9 is a characteristic diagram comparing the cross polarization discrimination characteristic (shown by a broken line B) of the first probe of the conventional coaxial-waveguide converter shown in FIG. FIG. 6 is a cross polarization discrimination degree characteristic (shown by a solid line A) of the second probe of the coaxial-waveguide converter according to the present invention shown in FIGS. 1A and 1B, and is shown in FIG. It is a characteristic view which compared the characteristic of the cross polarization discrimination degree characteristic (indicated by a broken line B) of the second probe of the conventional coaxial-waveguide converter.

Referring to FIGS. 3 and 4, first, regarding the conversion loss characteristics, the conventional coaxial-waveguide converter shown in FIG. 7 and the present invention shown in FIGS. 1 (a) and 1 (b) are used. Coaxial-
There is not much difference with the waveguide converter. On the other hand, regarding the cross polarization discrimination characteristic, the coaxial-waveguide converter of the present invention shown in FIGS. 1A and 1B is more conventional than the conventional coaxial-guide. It can be seen that it is superior to the wave tube converter. Thus, in the coaxial-waveguide converter of the present invention shown in FIGS. 1A and 1B, it is possible to improve the performance of the cross polarization protection ratio.

Also in the second embodiment shown in FIGS. 2A and 2B, similarly, the performance improvement of the high cross polarization protection ratio can be obtained.

[0025]

Since the present invention is constructed as described above,
The electric fields of the first and second linearly polarized waves are in the same direction, and can be detected by the first and second probes provided in the same direction on the same circuit board, respectively. Circuits for the first and second linearly polarized waves (horizontal polarized wave and vertical polarized wave) can be configured.

Further, in the case of such a complicated waveguide structure, it is usually impossible to manufacture the mold with a mold, or it is necessary to divide the waveguide into several parts and manufacture them, and then assemble them later. However, according to the present invention, since one side of the first and second rectangular waveguides is configured by the ground surface on the back surface of the circuit board, the minimum of the input waveguide and the two rectangular waveguides is provided. The waveguide can be composed of two parts. Therefore, the mass productivity of the product can be improved and the manufacturing cost can be reduced.

Further, with the structure as shown in FIGS. 2A and 2B, the mechanical structures of the two circuits for horizontal and vertical polarization can be made substantially the same or almost symmetrical. Therefore, the converter circuit NF (noise figure)
It is possible to improve the degree of separation between horizontal polarization and vertical polarization.

[Brief description of drawings]

1A and 1B are a horizontal sectional view and a vertical sectional view, respectively, of an embodiment of the present invention.

2A and 2B are a horizontal cross-sectional view and a vertical cross-sectional view, respectively, of another embodiment of the present invention.

FIG. 3 is a characteristic diagram comparing the conversion loss characteristic of the first probe shown in FIGS. 1A and 1B with the conversion loss characteristic of the first probe shown in FIG. 7.

FIG. 4 is a characteristic diagram comparing the conversion loss characteristics of the second probe shown in FIGS. 1A and 1B with the conversion loss characteristics of the second probe shown in FIG. 7.

5 is a characteristic diagram comparing the cross polarization discrimination characteristic of the first probe shown in FIGS. 1A and 1B with the cross polarization discrimination characteristic of the first probe shown in FIG.

6 is a characteristic diagram comparing the cross polarization discrimination characteristic of the second probe shown in FIGS. 1A and 1B with the cross polarization discrimination characteristic of the second probe shown in FIG. 8;

FIG. 7 is a partially cutaway cross-sectional perspective view showing an internal structure of a conventional example.

FIG. 8 is a partially cutaway cross-sectional perspective view showing the internal structure of another conventional example.

[Explanation of symbols]

 1 Horizontally polarized wave 2 Vertically polarized wave 3,4 Probe 5 Circular waveguide 6,7 Rectangular waveguide 8,9 Reflector 10 Circuit board 11 Cover 12 Chassis

Claims (2)

[Claims] 1. An input waveguide for transmitting first and second linearly polarized waves which are orthogonal to each other, and first and second rectangular shapes which are provided so as to be orthogonal to the input waveguide and further orthogonal to each other. A waveguide is provided, and the waveguides are bent in opposite directions by 45 degrees. One side of each waveguide is formed by a ground surface on the back surface of the circuit board, and one side of each waveguide is formed. A coaxial-waveguide converter having first and second probes respectively protruding from the circuit board into the respective waveguides. 2. A radio wave traveling direction of at least one of the first and second rectangular waveguides is bent substantially at right angles to the axial direction of the input waveguide, and the positions of the first probe and the second probe are input. The coaxial-waveguide converter according to claim 1, wherein the coaxial-waveguide converter is arranged substantially symmetrically with respect to the axis of the waveguide.