JP2006246314A - Wave polarizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a ceptum type wave polarizer that uses the properties of polarization that a ceptum which is a flat plate arranged in a waveguide is incapable of transmitting radio waves, when arranged in parallel to polarized waves and capable of passing the radio waves, when arranged orthogonally to the polarized wave can be made small-sized, but is disadvantageous in electric power resistance, since electric field is concentrated on the tip of the ceptum similar to a turn-style type. <P>SOLUTION: The wave polarizer as an embodiment of the present invention is equipped with a rectangular waveguide, a rectangular branch waveguide which branches off at right angles to an facing flank of the rectangular waveguide, and two ceptums which are provided in a space where the rectangular waveguide and rectangular branch waveguide cross each other and provided at right angles to the flank of the rectangular waveguide; and the interval between the ceptums is set to 0.18λ to 0.27λ, where λ is the wavelength of an electromagnetic wave passing through the rectangular waveguide, and the ceptums are arranged at positions of d/2 from the center axis of the rectangular waveguide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a demultiplexer used in microwaves and millimeter waves.

  In recent years, with an increase in communication capacity, a wider frequency band and polarization are often shared. For this reason, a demultiplexer is required to feed the satellite antenna. As this polarization splitter, one of two orthogonal polarizations is distributed to two opposing rectangular branching waveguides, and each polarization branching waveguide is squared at an angle of 90 degrees. A turn-style configuration that is arranged so as to expand is used (for example, Non-Patent Document 1). In addition, it is necessary to reduce the size of the equipment mounted on the satellite so that it can be placed in a limited space. One polarization is connected to one port, and the other polarization is connected to two rectangular branching waveguides. A septum-type configuration for distribution may be used (for example, Non-Patent Document 2).

Aramaki et al .: “Broadband design of thin-type demultiplexer using TURNSTILE branch circuit”, IEICE, C-2-44 (2003-3) Takashi Kitsuregawa, “SATELLITE COMMUNICATION ANTENNAS”, Artech House, p87, Fig1.61 (c)

  In order to increase the communication capacity, not only widening of the frequency band and polarization sharing due to the increase in the number of channels but also the handling of kW-class transmission power is increasing as the output increases. When mounted on a satellite, it is used in a vacuum. Therefore, when handling high power, it is necessary to consider that multi-pactor discharge does not occur in a vacuum. For this reason, there is a need for a polarization demultiplexer with excellent power durability while having broadband characteristics.

  There is a turn style type as a method of separating polarized waves. The turn style type has a feature that power is distributed because power is distributed from the branch circuit to the rectangular branch waveguide. However, the rectangular branching waveguide spreads in all directions, and it is necessary to take out each polarized wave after synthesizing / demultiplexing them again by the combiner / distributor, which makes the configuration complicated and increases the size of the demultiplexer / demultiplexer. There was a problem. In addition, the electric field is concentrated on the tip of the metal pyramid installed at the four-way branch portion for impedance matching, and there is a problem in that the power durability is deteriorated.

  In addition, there is a septum type in which a septum is inserted inside the waveguide to separate polarized waves. A septum is a flat plate placed inside a waveguide. When a flat plate is placed parallel to the polarization, radio waves cannot pass. Conversely, when a flat plate is placed perpendicular to the polarization, radio waves can pass. A septum-type demultiplexer is one that uses this polarization property. This septum type has the feature that it can be downsized. However, like the turn style type, there is a problem that the electric field is concentrated at the tip of the septum, which is disadvantageous in terms of power resistance.

  A demultiplexer according to the present invention includes a rectangular waveguide, a rectangular branched waveguide that branches at right angles to opposite side surfaces of the rectangular waveguide, the rectangular waveguide, and the rectangular branched waveguide. Two septums provided in intersecting spaces and provided at right angles to the side surface of the rectangular waveguide, and the distance d between the septums is λ the wavelength of electromagnetic waves passing through the rectangular waveguide 0.18λ to 0.27λ, and the septum is arranged at a position d / 2 from the central axis of the rectangular waveguide.

  According to the present invention, it is possible to obtain a polarization demultiplexer having excellent power resistance.

Embodiment 1
1 to 5 are diagrams showing Embodiment 1 of the present invention. FIG. 1 shows a demultiplexer 1 according to the present invention. The demultiplexer 1 includes a rectangular waveguide 2, a first rectangular branch waveguide 3, and a second rectangular branch waveguide 4.

  The first rectangular branch waveguide 3 and the second rectangular branch waveguide 4 are connected to the left and right side surfaces of the rectangular waveguide 2 so as to be orthogonal to the rectangular waveguide 2. That is, the first rectangular branch waveguide 3 and the second rectangular branch waveguide 4 are provided at right angles to the opposite side surfaces of the rectangular waveguide 2. The central axes 5 of the first rectangular branch waveguide 3 and the second rectangular branch waveguide 4 are made to coincide.

  A septum 6 that separates the first polarization 7 and the second polarization 8 that pass through the rectangular waveguide 2 is provided inside the rectangular waveguide 2. The septum 6 is provided in a space where the rectangular waveguide 2, the first rectangular branch waveguide 3, and the second rectangular waveguide 4 intersect. As an example, the first polarization 7 is horizontal polarization, and the second polarization 8 is vertical polarization.

  The septum 6 is parallel to the central axis 5 of the first rectangular branch waveguide 3 and the second rectangular waveguide 4. The septum 6 is provided at right angles to the side surface of the rectangular waveguide 2 where the first rectangular waveguide 3 and the second rectangular waveguide 4 are provided.

  Of the received signals of the first polarization 7 and the second polarization 8 input from the rectangular waveguide 2, the second polarization 8 of the electric field parallel to the septum 6 is the first rectangular branch waveguide. 3, distributed to the second rectangular branching waveguide 4. The first rectangular branching waveguide 3 and the second rectangular branching waveguide 4 become the second polarized wave 9 that is demultiplexed and has a phase difference of 180 degrees. The first polarization 7 passes through the rectangular waveguide 2 as it is.

  That is, the first polarized wave 7 input to the rectangular waveguide 2 passes through the rectangular waveguide 2 as it is, and the second polarized wave 8 is distributed by the septum 6 to be the first rectangular branched waveguide 3. And the second rectangular branch waveguide 4.

  2A is a septum shape, FIG. 2B is an XZ sectional view of a septum branch circuit, and FIG. 2C is an XY sectional view. The definition of the coordinate axes X, Y, and Z is the same as that shown in FIG. As shown in FIG. 2A, the septum 6 includes a square convex portion 10 and an inclined portion 11 continuously connected to the square convex portion 10. The bottom of the septum 6 is a flat surface 12. Of course, the septum 6 may be very thin, and the flat surface 12 may be uneven within the range of manufacturing errors. In other words, the width of the plane 12 may be very narrow, less than millimeters.

  Further, as shown in FIG. 2B, the demultiplexed second polarized wave 9 passing through the first rectangular branch waveguide 3 and the demultiplexed light passing through the second rectangular branch waveguide 4 are separated. Further, since the phase is 180 degrees different from that of the second polarization 9, the direction of the arrow is different.

  In the polarization splitter 1, since one polarized wave is extracted in the tube axis direction of the rectangular waveguide 2, the number of waveguide terminals is less than that of the turn style type, and only one combiner / distributor is used. This eliminates the need for a bend waveguide, so that downsizing can be realized.

  By passing the first polarized light 7, the electric field concentrates on the tip of the septum 6, but the electric field does not concentrate by flattening the tip of the square projection 10. Moreover, the electric field strength is dispersed by using two septums 6.

  As shown in FIG. 2C, the interval between the septums 6 is d. Since the second polarization 8 has two septa, the maximum electric field is not concentrated and the power durability can be improved. Details are described below.

  FIG. 3 shows power resistance and reflection characteristics when the distance between the two septums d shown in FIG. In FIG. 3, the horizontal axis indicates the septum distance d / λ. Here, λ is the wavelength of the electromagnetic wave passing through the rectangular waveguide 2. Further, the left scale indicates the withstand power kW, and the right scale indicates the reflection characteristic dB.

  According to FIG. 3, the reflection characteristic shows an extreme value in the range of 0.18λ to 0.27λ. However, since the reflection characteristic only needs to be −20 dB or less in actual operation, the interval d is 0.15λ to 0.3λ. It only has to be. In addition, although the power durability characteristic shows a substantially constant value at 0.25λ or more, it is sufficient that the power durability is 60 kW or more in actual operation, and therefore it may be 0.15λ or more. From the above, the distance d is excellent in the range of 0.18λ to 0.27λ. Note that the septum 6 is equally disposed on the left and right sides from the central axis of the rectangular waveguide 1.

  Further, although the reflection is increased by flattening the tip, matching can be achieved by selecting an appropriate value for the size of the convex portion. 4A is a diagram showing the relationship between the half width rk of the square convex portion 10 and the reflection characteristics, and FIG. 4B is a diagram showing the relationship between the height Δh of the square convex portion 10 and the reflection characteristics. It is.

  From FIG. 4A, when the half width rk of the square convex portion 10 is about 0.002λ to 0.003λ, the reflection characteristic is −20 dB or less. Also, from FIG. 4B, when the height Δh of the rectangular convex portion 10 is about 0.14λ to 0.17λ, the reflection characteristic is −20 dB or less. Therefore, the half width rk of the square protrusion 10 is excellent from 0.002λ to 0.003λ, and the height Δh of the square protrusion 10 is excellent from 0.14λ to 0.17λ.

  The first polarized wave 7 increases the electric field at the square convex portion 10 of the septum 6, and the second polarized wave 8 increases the electric field at the inclined portion 11 of the septum 6. Therefore, by using this septum structure, the first polarized wave 7 and the second polarized wave 7 can be changed in position where the electric field strength becomes strong, and the second polarized light 7 can change the position where the electric field strength becomes strong. . As a result, it is possible to provide the polarization demultiplexer 1 having excellent power durability.

  3 and 4, as shown in FIG. 2A, the sum of the height of the rectangular convex portion 10 and the height of the inclined portion 11 is 0.40λ, and the other height is 0.42λ. However, it may be appropriately changed according to the design.

  Of course, depending on the design, the number of septums 6 may be four as shown in FIG. That is, when the two septums 6 are shifted from the center, the isolation between the polarizations of the first polarization 7 and the second polarization 8 may not be sufficiently achieved. By doing so, it is possible to improve the polarization isolation.

  6 to 8 are views of the septum 6 in another embodiment. By changing the shape of the septum 6 in FIGS. 6 to 8, it is possible to finely adjust the reflection of the first polarized wave 7 and the power durability characteristics.

  In FIG. 6, a V-shaped protrusion 13 is provided by two surfaces instead of the flat surface 12 of the septum 6 shown in FIG. By providing the V-shaped protrusion 13 on the septum 6, the septum 6 becomes tapered, and the reflection of the first polarized wave 3 generated by the septum can be reduced.

  In FIG. 7, a V-shaped cut 14 is provided by two surfaces instead of the flat surface 12 of the septum 6 shown in FIG. By providing the V-shaped cut 14 in the septum 6, the reflection of the first polarized wave 3 can be reduced, and the septum 6 can be miniaturized.

  In FIG. 8, instead of the flat surface 12 of the septum 6 shown in FIG. 2A, convex cuts 15 are provided by a plurality of surfaces. As a result, the current on the septum 6 of the first polarization 7 can be changed to achieve power dispersion and improve power durability. In FIG. 8, a hole 16 is provided. Thereby, it can reduce in size / weight.

  The width of the surface may be extremely thin.

  As described above, by changing the shape of the leptum 6, it is possible to finely adjust the power durability, and it is possible to reduce the size and weight.

  As described above, according to the present invention, it is possible to obtain a polarization demultiplexer having excellent power resistance.

1 shows a polarization demultiplexer according to a first embodiment. FIG. 3 is a diagram showing the shape of the septum of the first embodiment. It is a withstand power and reflection characteristic figure at the time of septum space | interval change. It is a reflection characteristic figure when changing a septum shape. 1 shows a demultiplexer according to Embodiment 1 including a plurality of septa. It is a septum shape figure. It is a septum shape figure. It is a septum shape figure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Polarization demultiplexer, 2 Rectangular waveguide, 3 1st square branch waveguide, 4 2nd square branch waveguide, 5 Center axis, 6 Septum, 7 1st polarization, 8 2nd Polarized wave, second polarized wave divided by 9, 10 square convex part, 11 inclined part, 12 plane, 13 V-shaped protrusion, 14 V-shaped cut, 15 convex cut, 16 holes.

Claims (6)

A rectangular waveguide;
A rectangular branch waveguide that branches perpendicularly to opposite sides of the rectangular waveguide; and
Two septums provided in a space where the rectangular waveguide and the rectangular branching waveguide intersect, and provided at right angles to the side surface of the rectangular waveguide,
The interval d of the septum is 0.18λ to 0.27λ, where λ is the wavelength of the electromagnetic wave passing through the rectangular waveguide,
The septum is a demultiplexer disposed at a position d / 2 from the central axis of the rectangular waveguide. 2. The demultiplexer according to claim 1, wherein the septum includes a square convex portion and an inclined portion continuously connected to the square convex portion. The wavelength of the electromagnetic wave passing through the rectangular waveguide is λ, the half width rk of the convex portion of the rectangular shape is 0.002λ to 0.003λ, and the height Δh is 0.14λ to 0.17λ. The demultiplexer. The demultiplexer according to claim 2 or 3, wherein the bottom of the septum is a surface. The demultiplexer according to claim 2 or 3, wherein a bottom portion of the septum constitutes a V-shaped protrusion. The demultiplexer according to claim 2 or 3, wherein a bottom of the septum forms a V-shaped cut.

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