JPH04267602A - Circularly polarized wave/linearly polarized wave converter - Google Patents

Abstract

PURPOSE:To realize the small sized, easily processed and economical circularly polarized wave/linearly polarized wave converter with respect to the circularly polarized wave/linearly polarized wave converter employing a waveguide. CONSTITUTION:A primary radiator 1 is bonded to one end of a circular waveguide 2, a termination face 7 is provided to the other end, and a signal input output means such as a probe 4 is provided to the primary radiator 1. A 1st means reflecting one mode of an electromagnetic wave propagated in two orthogonal modes in the circular waveguide 2 such as a metallic plate 5, and a 2nd means reflecting the other mode of the electromagnetic wave such as a metallic plate 6 are provided on the termination face 7. The electromagnetic wave of the circularly polarized wave made incident in the primary radiator 1 is converted by a difference of the reflection path of both the modes into a linearly polarized wave and coupled with the probe 4, which sends a signal to a BS converter. A square waveguide is used in place of the probe 4 and the electromagnetic wave may be reflected in the opening of the slot provided on/the termination face 7 and the termination face in place of the metallic plates 5,6.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a circularly polarized wave/linearly polarized wave converter using a waveguide, and when used on the receiving side, converts circularly polarized wave to linearly polarized wave. The present invention relates to a device that can be used as a circularly polarized wave generator, and when used on the transmitting side, can be used as a circularly polarized wave generator that converts linearly polarized waves into circularly polarized waves and radiates circularly polarized waves.

0002

[Prior Art] In a conventional circularly polarized wave/linearly polarized wave converter, as shown in FIG.
, a circular waveguide 2 provided with a space portion 21 for impedance matching with a phase circuit 20, and an excitation probe 4. A primary radiator 1 is connected to one end of the circular waveguide 2. The circularly polarized satellite broadcast signal received by the parabolic antenna is input to the primary radiator 1, and the circularly polarized radio wave input to the primary radiator 1 is converted into a linearly polarized wave by the phase circuit 20. An electric signal is excited by the radio wave converted into a linearly polarized wave in the excitation probe 4 provided in the spatial part 21 for impedance matching with the excitation probe 4, and the electric signal is sent to the BS converter by the excitation probe 4. It was designed to transmit converted satellite broadcast signals.

0003

[Problem to be Solved by the Invention] Therefore, the circular waveguide 2
Since a space portion 21 for so-called impedance matching is provided inside the circular waveguide 2, the length of the circular waveguide 2 becomes long, and the phase circuit 20 provided inside the circular waveguide 2
When using a structure that is integrated with the circular waveguide 2, a mold corresponding to the space portion 21 is required in addition to a mold corresponding to the phase circuit 20 portion, resulting in a large number of molds. There was a problem that it was difficult to process. The present invention shortens the length of the circular waveguide 2 by providing an electromagnetic wave reflection means on the end surface of the circular waveguide 2, thereby eliminating the space portion 21 and the phase circuit 20 for achieving so-called impedance matching. Furthermore, since there is no need to provide the phase circuit 20 or the space 21 of the circular waveguide 2, a simplified mold can be used, making it easy to process, compact and economical circularly polarized/linearly polarized waves. The purpose is to provide a converter.

0004

[Means for Solving the Problems] FIG. 1 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing one embodiment of the present invention. In a circular waveguide 2 having an opening for inputting and outputting polarized electromagnetic waves, for example a primary radiator, and a termination surface 7 at the other end, a signal input/output means, for example a probe 4 is provided on the opening side. A first means, for example, a metal plate 5, for reflecting one mode of the electromagnetic waves propagating in two orthogonal modes in the circular waveguide 2, and a second means, for example, for reflecting the other mode of the electromagnetic waves, for reflecting the electromagnetic waves in two orthogonal modes. A plate 6 is provided on the termination surface 7 side, and the circularly polarized electromagnetic wave is converted into a linearly polarized wave by the reflection path difference between the two modes, which is coupled to the probe 4, and the probe 4 sends a signal to the BS converter. I'm trying to transmit it. A rectangular waveguide is used instead of the probe 4, and a terminal surface 7 is used instead of the metal plates 5 and 6.
The structure may be such that electromagnetic waves are reflected at the opening of the groove provided in the groove and the end face of the same groove.

[0005]

[Operation] With the above-described configuration, the present invention has a first means for reflecting one mode of electromagnetic waves propagating in two orthogonal modes in the circular waveguide 2, and a second means for reflecting the other mode of the electromagnetic waves. means for converting the circularly polarized electromagnetic wave into a linearly polarized wave by the reflection path difference between the two modes and coupling it to the input/output means, so that the input/output means transmits an electrical signal to the BS converter. ing. FIG. 3 is an equivalent configuration diagram for explaining the principle of the circularly polarized wave/linearly polarized wave converter of the present invention. Assuming that a current I is applied to excite radio waves, the electromagnetic field E directed toward the opening of the circular waveguide 2 consists of an electromagnetic field component Ea directed directly toward the opening from the probe 4, and an electromagnetic field component Ea that exits the probe 4 and is reflected at the end surface 7. It is expressed as a combination with the electromagnetic field component Eb directed toward the aperture. Therefore, E=Ea +Eb...■

[0006] Let Z = 0 at the end surface of the circular waveguide, take the Z axis in the direction of the tube axis, and let A = amplitude constant of the radio wave in the circular waveguide β = wave number of the radio wave in the circular waveguide, then Ea is expressed by the following equation. Ea =A・exp[j{ωt−β(Z−L)}]・・
...■ Eb is equivalent to excitation of a radio wave by passing current -I through the probe 8 at a position L to the right from the termination surface 7, as shown in Fig. 3, and is expressed by the following formula. . Eb =-A・exp[j{ωt-β(Z+L)}]・
...■ Therefore, E is expressed by the following formula from the formulas ■, ■, and ■. E=A・exp[j{ωt−β(Z−L)}]
−A・exp[j{ωt−β(Z+L)}]
=A・exp[j{ωt−βZ}]・[exp
{jβL}−exp {−jβL}] =j2
A・SIN (βL)・exp [j{ωt−βZ
}] ...■ Therefore, when electromagnetic waves are excited by the probe 4, the phase of the electromagnetic waves generated in the circular waveguide 2 is determined by the distance Z from the end surface 7 and the wave number β according to the formula ■. It shows that things change.

FIG. 4 is an explanatory diagram of the principle of the circularly polarized wave/linearly polarized wave converter of the present invention, in which the mounting position of the probe 4 is set at Z=0, and Z In the left figure, the distance between the probe 4 mounting position and the electromagnetic wave reflecting surface 9 is Lc, and in the right figure, the distance between the probe 4 mounting position and the electromagnetic wave reflecting surface 10 is Ld. Therefore, the electromagnetic fields Ec and Ed directed toward the opening of each circular waveguide can be expressed as follows from equation (2). Ec=j2A・SIN(βLc)・exp[j{
ωt−β(Z+Lc) }] ・・・■ Ed=j
2A・SIN(βLd)・exp[j{ωt−β(
Z+Ld) }] ... ■The phase difference between Ec and Ed is β(
Ld-Lc), and if the values of Ld and Lc are selected so that the following formula holds, |β(Ld-Lc)|=π/2... ■The phase difference between Ec and Ed is 90 degrees. be able to.

FIG. 5 is an explanatory diagram of the electric field distribution mode of an electromagnetic wave propagating in a circular waveguide, and the TE11 mode, which is the fundamental mode of the circular waveguide, has two orthogonal modes, mode 1 and mode 2, as shown in the figure. In Figure 5, if the vertical direction is the Y axis and the horizontal direction is the X axis, mode 1 has an electric field parallel to the Y axis, and mode 2 is an electric field distribution mode with an electric field parallel to the X axis. It has become. In FIG. 4, a reflecting surface 9 and a reflecting surface 10 are provided in the same circular waveguide 2, and the probe 4 excites linearly polarized electromagnetic waves so that the two modes shown in FIG. 5 exist, and mode 1 is reflected. If the mode 2 is reflected by the surface 9 and the mode 2 is reflected by the reflective surface 10, and the values of Ld and Lc are selected so that the formula Therefore, the relationship holds that the circularly polarized electromagnetic wave incident on the opening of the circular waveguide 2 is converted into a linearly polarized electromagnetic wave at the position of the probe 4.

[0009] In this way, the space portion 21 and the phase circuit 20 for impedance matching inside the circular waveguide 2 that have been conventionally used can be deleted, and electromagnetic waves can be transmitted to the end face of the circular waveguide 2. By providing the reflecting means, the length of the circular waveguide 2 can be shortened, and the mold can be simplified since there is no need to provide the phase circuit 20 or the space portion 21 of the circular waveguide 2. Therefore, it is possible to provide a circularly polarized wave/linearly polarized wave converter that is easy to process, small, and economical.

0010

[Embodiment] FIG. 1 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing an embodiment of the present invention, and FIG. 2 is a front view of FIG. As shown, the primary radiator 1 is joined to one end of the circular waveguide 2 as an opening through which circularly polarized electromagnetic waves can be input and output, and the termination surface 7 is provided at the other end. A probe 4 is provided on the first side as a signal input/output means. As shown in FIG. 5, a metal plate 5 is provided parallel to the X axis as a means for reflecting mode 2 of the electromagnetic waves propagating in the circular waveguide 2 in two orthogonal modes, and the other mode 1 is reflected. As a second means for this purpose, a metal plate 6 is provided in a direction parallel to the Y axis, and the metal plate 5 and the metal plate 6 are attached at right angles to the terminal surface 7. The distance between the tip of the metal plate 5 and the probe 4 and the distance between the tip of the metal plate 6 and the probe 4 are set so that the theoretical formula (■) holds true, but the arrangement is slightly adjusted to adjust the difference in the reflection paths of the two modes. The circularly polarized electromagnetic waves are converted into linearly polarized waves at the position of the probe 4.

The probe 4 is held by a fixture 3 and inserted into the circular waveguide 2 from the outside, and the installation angle of the probe 4 is approximately 45 degrees with respect to the Y axis (or X axis). It is made to combine with the composite electric field of the electric field component in the Y-axis direction (mode 1) and the electric field component in the X-axis direction (mode 2),
As shown in the theoretical formulas (■) and (■) in the section on the effect, the electric field component in the X-axis direction and the electric field component in the Y-axis direction have different amplitudes, and S
Since IN (βLc) and SIN (βLd),
The mounting angle of the probe 4 (45 degrees) was slightly adjusted, and the length of the probe 4 inserted into the circular waveguide 2 was also adjusted so that the coupling was optimal for linearly polarized radio waves. This ensures that a high signal level is obtained.

Both ends of each of the metal plates 5 and 6 are sandwiched and fixed between the inner walls of the circular waveguide 2.
Because the metal plates are made to intersect in the center,
One side now holds the other, making it easier to attach the metal plate at right angles to the end face 7. If it is not necessary in terms of strength, remove either the metal plate 5 or 6 and reflect each mode of the electromagnetic wave at the tip of the metal plate and the end surface 7 of the circular waveguide 2, so that the theoretical formula (■) holds true. The arrangement may be slightly adjusted to adjust the reflection path difference between the two modes so that the circularly polarized electromagnetic wave is converted to linearly polarized wave at the position of the probe 4.

FIG. 6 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing another embodiment of the present invention, and FIG.
6 is a front view of FIG. 6, and the difference from the embodiment shown in FIGS. 1 and 2 is that instead of using metal plates 5 and 6 as the electromagnetic wave reflecting means, a metal lump is used to provide a groove. It is a point. Two substantially semi-cylindrical metal lumps 11 and 12 are provided on opposing arcuate portions of the inner wall portion of the terminal end surface 7 of the circular waveguide 2 so that the arcuate portions are flat, and the same planes are opposed to A groove is provided between the metal lumps (11, 12). The shape of the groove viewed from the opening surface of the circular waveguide 2 is such that the width D of the groove is in the X-axis direction and the long side of the groove is located in the Y-axis direction. The distance to the end surface 7 is L
d, and the height of the metal lumps 11 and 12 from the end surface 7 is L.
It is set as e.

When the width D of the groove is made narrower than 1/2 of the wavelength of the electromagnetic wave propagating inside the circular waveguide 2, the electromagnetic wave of mode 1 having an electric field distribution in the Y-axis direction moves slightly inside the groove from the entrance of the groove. The light is reflected at the point where it enters the probe 4, and the distance between this reflecting surface and the probe 4 is defined as Lc. On the other hand, the electromagnetic wave of mode 2, which has an electric field distribution in the X-axis direction, enters the inside of the groove because the groove part becomes a propagation mode, and is reflected at the end surface 7 of the circular waveguide 2, which corresponds to the bottom of the groove. Become. Therefore, if the relationship between Lc and Ld is set so that the theoretical formula (■) holds true, the reflected waves of mode 1 and mode 2 can be converted into linearly polarized waves at the position of the probe 4, but in reality, the waves at the entrance of the groove Since the electric field distribution mode of the electromagnetic waves changes, higher-order modes are generated, so the arrangement is adjusted somewhat so that the electromagnetic waves in both modes are converted into linearly polarized waves at the position of the probe 4. The mounting angle of the probe 4 is the same as in the embodiment shown in FIGS. 1 and 2.

FIG. 8 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing another embodiment of the present invention, and FIG.
8 is a front view of FIG. 8, and the difference from the embodiments shown in FIG. 6 and FIG. Similarly, in the embodiments shown in FIGS. 1 and 2, a rectangular waveguide 13 may be joined to the side surface of the circular waveguide 2 instead of using a probe. good. A coupling slit 14 is provided on the side surface of the circular waveguide 2 so that the long side of the slit 14 is parallel to the tube axis of the circular waveguide 2, and the short side of the slit 14 when projected on a vertical plane is in the vertical direction. I am trying to make it so that The tube axis 15 of the rectangular waveguide 13 is joined in the direction that matches the probe 4 in FIGS. 6 and 7, and the joining position is adjusted slightly in the same way as the example using the probe 4 in FIGS. The rectangular waveguide 13 is arranged so that the polarized wave is optimally coupled to the radio wave.
This allows linearly polarized electromagnetic waves to be propagated efficiently.

[0016]

As explained above, according to the present invention, by eliminating the so-called spatial part and phase circuit for impedance matching and providing an electromagnetic wave reflecting means on the end face of the circular waveguide, The length of the circular waveguide can be shortened, and the mold can be made simpler than when a phase circuit is provided in the middle of the circular waveguide, making it compact and economical. A polarization converter can be provided.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing an embodiment of the present invention.

FIG. 2 is a front view of FIG. 1.

FIG. 3 is an equivalent configuration diagram for explaining the principle of the circularly polarized wave/linearly polarized wave converter of the present invention.

FIG. 4 is a diagram illustrating the principle of the circularly polarized wave/linearly polarized wave converter of the present invention.

FIG. 5 is an explanatory diagram of an electric field distribution mode of electromagnetic waves in a circular waveguide.

FIG. 6 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing another embodiment of the present invention.

FIG. 7 is a front view of FIG. 6;

FIG. 8 is a partially cutaway perspective view of a circularly polarized wave/linearly polarized wave converter showing another embodiment of the present invention.

FIG. 9 is a front view of FIG. 8;

FIG. 10 is a schematic diagram of a conventional circular polarization/linear polarization converter.

[Explanation of symbols]

1 Primary radiator 2 Circular waveguide 3 Fixing tool 4 Probe 5 Metal plate 6 Metal plate 7 End surface 8 Probe 9 End surface 10 End surface 11 Metal lump 12 Metal lump 13 Square waveguide 14 Slit 15 Tube shaft 20 Notch line 21 Phase circuit 22 Spatial part

Claims (6)

[Claims] Claim 1: A circular waveguide having an opening at one end that can input and output circularly polarized electromagnetic waves and a termination surface at the other end,
A signal input/output means is provided on the opening side, and a first means for reflecting one mode of electromagnetic waves propagating in two orthogonal modes in the circular waveguide and a second means for reflecting the other mode are provided. It is characterized in that it is provided on the termination surface side, converts the circularly polarized electromagnetic wave into a linearly polarized wave by the reflection path difference between the two modes, couples it to the input/output means, and transmits the signal by the input/output means. Circular polarization/linear polarization converter. 2. The first means comprises a metal plate parallel to the electric field direction of one mode, and the second means comprises a metal plate parallel to the electric field direction of the other mode. , both sides of the metal plates are sandwiched between the opposing inner walls of the circular waveguide and intersect with each other,
2. The circularly polarized wave/linearly polarized wave converter according to claim 1, wherein the circularly polarized wave/linearly polarized wave converter is attached to an end face of the same circular waveguide. 3. The first means is a terminal face of a circular waveguide, the second means is a metal plate parallel to the electric field direction of the other mode, and both side surfaces of the metal plate are 2. The circularly polarized wave/linearly polarized wave converter according to claim 1, wherein the circular waveguide is sandwiched between opposing inner walls of the circular waveguide and attached to the end face of the circular waveguide. 4. Two substantially semi-cylindrical metal lumps are provided on opposing circular arc portions of the terminal end face of the circular waveguide, and the circular arc portions are made into a planar shape, and the same planes are made to face each other to form a space between the two metal lumps. A groove is provided in the circular waveguide, the longitudinal direction of the groove is parallel to the electric field direction of one mode, and the width of the groove is set to be less than half the wavelength of the electromagnetic wave propagating in the circular waveguide. 2. The circularly polarized wave/linearly polarized wave converter according to claim 1, wherein the opening is an opening of the groove, and the second means is an end surface of the groove. 5. The input/output means comprises a probe,
2. The circular polarization/linear polarization conversion according to claim 1, wherein the probe is inserted into the circular waveguide from a side surface thereof in a direction parallel to the combined electric field of the two orthogonal modes. vessel. 6. The input/output means comprises a rectangular waveguide, and the tube axis of the rectangular waveguide is oriented parallel to the composite electric field of the two orthogonal modes, and the side surface of the circular waveguide is 2. The circularly polarized wave/linearly polarized wave converter according to claim 1, wherein the circularly polarized wave/linearly polarized wave converter is bonded to each other by providing a coupling opening therein.