JPH0322081B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an orthogonal polarization splitting device used in microwave and sub-millimeter wave antenna power feeding devices.

[Conventional technology]

In microwave or sub-millimeter wave communication,
In order to make effective use of frequencies, a frequency reuse method that simultaneously uses orthogonal polarization is adopted.
In addition, in order to perform transmission and reception at the same time, most of the antennas used for this type of communication use orthogonal polarization of linearly polarized waves or circularly polarized waves for two separated frequency bands. Among the polarization splitters used in the antenna feeding device of this type of antenna,
In a splitter that uses a method that polarizes the low frequency band ( ₁ ) and then the high frequency band ( ₂ ), it is possible to polarize the low frequency band ( ₂ ) without affecting the radio waves in the high frequency band (2) at all. An orthogonal polarization splitting device is required to simultaneously polarize two mutually orthogonal polarized waves ( ₁ ). This type of polarization splitter suppresses the polarization characteristics of the high frequency band ( ₂ ) and the excitation of higher-order modes that pass through its main wave tube, and polarizes only the low frequency band ( ₁ ). In order to do this, the part that performs polarization needs to have a coupling circuit that has small coupling to higher-order modes and maintains axial symmetry. This type of demultiplexer simultaneously demultiplexes orthogonally polarized waves through four coupling holes cut in the axial direction at 90° intervals on the circumference of a circular waveguide, which is the main transmission line. A balanced polarization splitter is effective.

This type of polarization splitting device combines four coupling holes and a branch waveguide with a _low -pass filter or a bandpass filter, each independently coupled to each polarization component, using a magic T. Then, two orthogonal polarization components are detected independently while separating the high frequency band.

[Problem that the invention aims to solve]

Conventional polarization splitting devices of this type perform polarization-specific synthesis using a combination of an ordinary curved waveguide and a magic T, which results in a large structure that makes it difficult to mount on a small antenna. There is a drawback.

An object of the present invention is to provide an orthogonal polarization splitting device that does not have the above-mentioned drawbacks.

[Means for solving problems]

The present invention utilizes a circular or square waveguide as the main transmission line that simultaneously transmits two or more frequencies with two orthogonal polarizations, and four coupling holes arranged symmetrically around the waveguide. It consists of branch transmission lines that are each independently coupled to the main transmission line, and a synthesis circuit unit that independently synthesizes two sets of branch transmission lines that are orthogonal to each other, and that has at least one frequency that is orthogonal to each other. In an orthogonal polarization demultiplexing device that simultaneously demultiplexes polarized waves, the branch transmission line coupled to the main transmission line has a ridge in the center and bends 90° within the electric plane while being displaced in the direction of the main transmission line. It is characterized by being composed of a shift-bend waveguide with a ridge.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cross-sectional side view showing the structure of the orthogonal polarization splitter of the present invention, and FIG. 2 is a cross-sectional view showing the structure of the orthogonal polarization splitter of the present invention. 1 shows a cross-sectional view of the structure of a shift bend waveguide with a ridge, which shows the characteristics of the shift bend waveguide.

In FIGS. 1 and 2, in order to perform frequency separation, the main circular waveguide 1 has a step conversion section 2 for impedance matching, and adjacent step conversion sections 2 are arranged axially symmetrically at every 90 degrees on the circumference. Four coupling holes 3a, 3b, 3c, and 3d cut in the direction are provided. These coupling holes are arranged symmetrically within a plane perpendicular to the tube axis of the main circular waveguide 1 in order to suppress the excitation of higher-order modes and the induction of polarization characteristics for radio waves of high frequency ( ₂ ). There is. Therefore, these 4
In order to demultiplex the low frequency ( ₁ ) coupled by the two coupling holes 3a, 3b, 3c, and 3d while performing polarization separation, it is necessary to It is necessary to synthesize the radio wave components separately. One of the two orthogonal polarization components, horizontal polarization _{1 (} H) and vertical polarization ₁ (V)
The branch waveguide synthesis circuit for (H) includes shift bend waveguides 4a, 4c with ridges coupled to the main circular waveguide 1 via coupling holes 3a, 3c, low-pass filters 5a, 5c, and Consists of Magic T6. On the other hand, the branch waveguide synthesis circuit for ₁ (V) includes shift bend waveguides 4b and 4d with ridges coupled to the main circular waveguide 1 via coupling holes 3b and 3d, and a low-pass filter 5b. , 5d and Magic T7.

Shift bend waveguide with rigidity 4a, 4b, 4
c and 4d are the main circular waveguides 1 of the present invention, which are continuously displaced in the tube axis direction and have an E-bend of 90°, in order to avoid structural interference of the combining circuits having orthogonal polarization relationships. Characterize the waveguide. Low pass filters 5a, 5b, 5c, 5d are connected to coupling holes 3a, 3
High frequency ( ₂ ) combined at b, 3c, 3d
This is to block radio waves. Also, Magic T
6, T7 is the opposing coupling hole 3 of the main circular waveguide 1
This is a waveguide type hybrid that combines the same polarized wave components in the same phase by combining them at a, 3c and 3b, 3d. That is, in Magic T6 and T7, the H-plane arm is used as an output terminal, and the E-plane arm is terminated without reflection.

Shift bend waveguide with rigidity 4a, 4b, 4
c, 4d specifications and low pass filters 5a, 5
At positions b, 5c, and 5d, the radio waves of high frequency ( ₂ ) are polarized and demultiplexed for radio waves of low frequency ( ₁ ), which consists of the coupling hole groups 3a, 3b, 3c, and 3d and the branching waveguide synthesis circuit. In order to avoid interference caused by high frequency ( ₂ ) radio waves, the coupling hole is designed to have an electric field wall (transverse electric field is zero). The shift bend waveguide with a ridge has a 90° E bend while being largely displaced in the tube axis direction of the main circular waveguide 1.
In order to prevent the equivalent cross section in the transmission direction for low frequency ( ₁ ) radio waves from being smaller than the cross section of a normal waveguide and deteriorating the transmission characteristics, a ridge is provided in the center to widen the electrical equivalent cross section. The aim is to improve the transmission characteristics.

In the orthogonal polarization splitter having the above configuration, one terminal #1 of the main circular waveguide 1 is connected to the orthogonal polarization ₁ (V/H) with a lower frequency than the antenna side and the orthogonal polarization ₂ (V/H) with a higher frequency than the antenna side. V/H) is input, and the terminal #1 side waveguide transmits a low frequency orthogonal polarized wave ₁ (V/H) and a high frequency orthogonal polarized wave ₂ (V/H).
The other terminal #2 waveguide of the main circular waveguide 1 is selected as a cutoff region for the low frequency ₁ and transmits only the high frequency orthogonally polarized wave ₂ (V/H). The step converter 2 performs impedance matching between the terminal #1 side waveguide and the terminal #2 side waveguide. The low frequency horizontally polarized waves ₁ are combined through the coupling holes 3a and 3c,
They pass through low-pass filters 5a and 5c, are combined by magic T6, and are detected at detection terminal #3.
On the other hand, the low frequency vertically polarized wave ₁ (V) is
b and 3d, pass through low-pass filters 5b and 5d, respectively, and are synthesized by magic T7 and detected at detection terminal #4. In such polarization-specific synthesis, according to this embodiment, a shift bend waveguide with a ridge is used as the connection waveguide connecting the coupling hole and the low-pass filter, so that the polarization of the branch waveguide can be adjusted. Interference that occurs during wave-by-wave synthesis can be prevented.

In this way, the low frequency ( ₁ ) radio wave is split, and the high frequency orthogonal polarized wave ₂ (V/H) is detected at the terminal 2 of the main circular waveguide 1.

In the above embodiments, a circular waveguide was used as the main transmission line, but it is clear that a square waveguide can also be used. Further, although a low-pass filter is used in the synthesis circuit, a band-pass filter may also be used. Furthermore, in the above embodiment, two frequencies are simultaneously transmitted using polarized waves orthogonal to the main transmission line, but the present invention is not limited to this. Three or more frequencies are transmitted, and at least one frequency is polarized at right angles to each other. It goes without saying that the present invention can be applied to an orthogonal polarization demultiplexing device that simultaneously demultiplexes.

〔Effect of the invention〕

As explained above, according to the present invention, by using a shift bend waveguide with a rigid between the coupling part of the main waveguide and the filter, structural interference between the branch waveguide synthesis circuits can be avoided and the path can be shortened. Since it is possible to combine the polarized waves over a long length, it is possible to provide a small-sized and low-loss polarization demultiplexing device.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional side view of a polarization splitter according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the polarization splitter according to an embodiment of the present invention. 1... Main circular waveguide, 2... Step conversion section,
3a, 3b, 3c, 3d...Binding hole, 4a, 4
b, 4c, 4d...Shift bend waveguide with ridge, 5a, 5b, 5c, 5d...Low pass filter, 6, 7...Magic T.

Claims (1)

[Claims] 1 A circular or square waveguide as a main transmission line that simultaneously transmits two or more frequencies with two orthogonal polarizations, and the main transmission via four coupling holes arranged symmetrically around this waveguide. Branch transmission lines each connected to the line independently, and two branch transmission lines that are orthogonal to each other.
an orthogonal polarization demultiplexing device that simultaneously demultiplexes mutually orthogonal polarized waves of at least one frequency, comprising a combining circuit unit that independently combines each set of the branch transmission lines, and is coupled to the main transmission line. orthogonal polarization, characterized in that the branch transmission line is constituted by a shift bend waveguide with a ridge having a ridge in the center and having a 90° bend within the electric surface while being displaced in the direction of the main transmission line. Demultiplexing device.