JPH0113441Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention uses a circular main waveguide as the main waveguide, and transmits only a single polarized wave, while each of the horizontal and vertical orthogonal polarized waves that are transmitted independently and coexist within the circular main waveguide. The present invention relates to an improvement in a polarization splitter that branches polarized waves transmitted in a rectangular waveguide into a rectangular waveguide, or conversely combines polarized waves transmitted in a rectangular waveguide into two horizontally and vertically orthogonally polarized waves in a circular main waveguide.

As is well known, a polarization splitter using a circular waveguide as the main waveguide consists of two types: an orthogonal polarization splitter in which two T-branch rectangular waveguides are coupled to the sides of the circular main waveguide, and one polarization splitter that uses a circular waveguide as the main waveguide. There is a coaxial polarization splitter in which a rectangular waveguide is T-branched to the side surface of a circular main waveguide, and another rectangular waveguide is connected in the axial direction of the circular main waveguide.

In particular, the latter uses a 1/4λg long step converter as a rectangular-circular converter, which makes it possible to shorten the length of the waveguide in the axial direction, resulting in a compact and good structure.
It is characterized by the ability to obtain VSWR characteristics.

Conventionally, the above-mentioned coaxial polarization splitter has a structure shown in FIG.

In Fig. 1, 1 is a circular main waveguide, 2 is a T-branched rectangular sub-waveguide, 3 is a coaxial rectangular sub-waveguide, 4 is a thin conductor plate, 5 is a coupling hole, and 6 is a 1/4λg length step converter. , 7 is a resonant window iris, 8 is a flange, and 9 is a fastening bolt.

Waves of polarized wave E ₁ and polarized wave E ₂ that entered the circular main waveguide 1 from the right side of Figure 1 are transmitted to the left side of the figure, and the polarized waves
The wave of E ₁ is reflected by the thin conductor plate 4 installed parallel to this, and passes through the coupling hole 5 to the T-branch rectangular sub-waveguide 2.
It is split into two waves.

On the other hand, the conductor thin plate 4 is set in a vertical plane with respect to the polarized wave E ₂ and in a position where reflection and loss can be ignored, and the wave of the polarized wave E ₂ further travels inside the circular main waveguide 1 as shown in FIG. The signal is transmitted to the left side, passes through a 1/4λg length step converter 6, a resonant window iris 7, and is branched into a coaxial rectangular sub-waveguide 3. The 1/4λg length step converter 6 and the resonant window iris 7 are sandwiched between a flange 8 of the circular main waveguide and the coaxial rectangular sub-waveguide and fastened with bolts 9.

As described above, the conventional polarization demultiplexer having the structure shown in FIG. The impedance matching between the tube and the circular main waveguide can be achieved, and good VSWR characteristics can be obtained.Furthermore, by providing the conductor thin plate 4 in the plane perpendicular to the polarized wave E ₂ , the transmission of the T-branch rectangular sub-waveguide 2 is improved. It has the characteristics of preventing waves from leaking to the side of the coaxial rectangular sub-waveguide 3 and obtaining good coupling properties.

However, in a polarization splitter with this structure, a 1/4λg length step converter 6 processed into a cylindrical shape and a thin resonant window iris 7 are placed between the circular main waveguide 1 and the flange 8 of the coaxial rectangular sub-waveguide 3. Because they are fastened with clamping bolts, they have the drawback of being large and heavy, especially for low-frequency microwave bands such as the 2 GHz and 4 GHz bands, because the pipe wavelength is long. If further airtightness inside the polarization splitter is required, install an O-ring or other airtight seal on each joint surface of the circular main waveguide flange, 1/4λg length step converter, resonant window iris, and coaxial rectangular sub-waveguide flange. It became necessary to provide packing for holding, which resulted in a complicated structure and a lack of economic efficiency.

The purpose of this invention is to solve the above-mentioned drawbacks of conventional polarization demultiplexers and to provide a small, lightweight, and economical polarization demultiplexer.

FIG. 2 is a configuration diagram of a polarization splitter showing an embodiment of this invention, in which a thin resonant window 11 is provided at the joint between the coaxial rectangular sub-waveguide 3 and the circular main waveguide 1. A 1/4λg long conductor 10 with a substantially semicircular cross section is provided at the end of the circular main waveguide 1 in contact with the surface of the resonance window 11 to constitute a rectangular-circular converter, and the waveguide of the rectangular-circular converter portion is A thin conductor plate 4 is provided on a plane located on the tube axis and perpendicular to the electric field E ₂ of the transmitted wave of the coaxial rectangular sub-waveguide 3 to form a coaxial rectangular sub-waveguide 3 with polarized wave E ₁ . This is a polarization demultiplexer characterized by preventing leakage to.

As shown in FIG. 2, the polarization demultiplexer of this invention uses, for example, two 1/4λg long conductors 10 each having a substantially semicircular cross section, and the surfaces of the conductors facing the central axis of the circular main waveguide 1 are common. It is set in a plane orthogonal to the polarization E ₂ of the axially rectangular sub-waveguide 3 to form an equivalent 1/4λg step converter that contributes to impedance matching between the circular main waveguide impedance and the coaxial rectangular auxiliary waveguide. Furthermore, a plane located on the waveguide axis of this converter section and orthogonal to the electric field of the polarized wave E ₂ transmitted through the coaxial rectangular sub-waveguide 3, that is, the electric field of the polarized wave E ₁ A thin conductor plate 4 is provided on parallel surfaces to prevent polarized wave E ₁ from leaking to this area, and further eliminates the need for TE ₀₁ waves, etc., which have the same electric field component as the polarized wave E ₁ in this area. This prevents the generation of attitude waves. Strictly speaking, the dimensions and setting positions of each part of the approximately semicircular cross-section 1/4λg long conductor, and the dimensions and setting positions of each part of the thin conductor plate are set to values that can achieve electrically effective impedance matching, or to prevent the occurrence of unnecessary configurations. The value is selected to form an electrically effective shorting plate that blocks the transmission of polarized wave E ₁ .

In addition, the branching paths of the polarized waves E ₁ and E ₂ in the circular main waveguide to the T-branch rectangular sub-waveguide and the coaxial rectangular sub-waveguide in the polarization splitter of this invention as shown in Fig. 2 are as follows. The principle is the same as that in the conventional polarization splitter shown in FIG.

Furthermore, it goes without saying that the thin conductor plate 4 can be replaced by a plurality of electrically equivalent conductor rods.

As described above, in the polarization splitter of this invention, a 1/4λg long conductor with an approximately semicircular cross section is loaded into a circular main waveguide to form an impedance step converter. A T-branched rectangular sub-waveguide, which is located in the coaxial rectangular sub-waveguide and is connected to the side surface of the circular main waveguide by providing a thin conductor plate or a plurality of conductor bars on a plane orthogonal to the polarized wave transmitted through the coaxial rectangular sub-waveguide. To prevent leakage of polarized waves transmitted through the tube toward the coaxial rectangular sub-waveguide,
Furthermore, this converter part has a structure that suppresses the generation of unnecessary state waves equivalent to TE ₀₁ waves for the coaxial rectangular sub-waveguide, and is an extremely effective device that maintains good electrical characteristics and achieves a small size and light weight. It is something.

In addition, the polarization splitter of this invention has a structure that allows easy assembly of each component by, for example, welding.
Even when airtightness is required, this function can be achieved without creating a complicated structure or adding components, and it is extremely effective economically.

[Brief explanation of the drawing]

Fig. 1 shows the structure of a conventional polarization splitter, and Fig. 2 shows the structure of the polarization splitter of this invention. 1 is a circular main waveguide, 2 is a T-branch rectangular sub-waveguide, and 3 is a Coaxial rectangular sub-waveguide, 4 is a thin conductor plate, 5 is a coupling hole, 6 is 1/4
λg length step converter, 7 is resonant window iris, 8
9 is a flange, 9 is a fastening bolt, 10 is a 1/4λg long conductor with a substantially semicircular cross section, and 11 is a resonant window. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Scope of utility model registration request] A circular waveguide is used as the main waveguide, and one of the horizontal and vertical orthogonal polarized waves transmitted inside the circular main waveguide is coupled to the T-branch square sub-waveguide on the side of the circular main waveguide. In a polarization splitter that splits one polarized wave into a coaxial rectangular sub-waveguide coupled to one open end of a circular main waveguide, the coaxial rectangular sub-waveguide and the circular main waveguide are A resonant window is provided at the junction, and a 1/4λg with approximately semicircular cross section is attached to the end of the circular main waveguide in contact with the resonant window surface.
A long conductor is provided to constitute a rectangular-circular transducer, and located on the waveguide axis of the rectangular-circular transducer portion,
In addition, a thin conductor plate or a plurality of conductor bars are provided on the plane perpendicular to the electric field of the transmitted wave of the coaxial rectangular sub-waveguide, so that the coaxial rectangular sub-waveguide side of the transmitted wave of the T-branched rectangular sub-waveguide is provided. A polarization demultiplexer characterized in that it is formed to prevent leakage.