JPH0512881B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the configuration of a polarization splitter for feeding an antenna that is shared by two separate frequency bands in the microwave and millimeter wave bands.

Conventionally, in a parabolic antenna, a single primary radiator is used as a polarization demultiplexer that excites a common waveguide with polarized waves in two separate frequency bands, each of which can be used in orthogonal directions.
Several configurations have been put into practical use, each with advantages and
It has drawbacks.

The details will be explained below with reference to the drawings. FIGS. 1A and 1B are perspective views showing an example of the configuration of a conventional polarization splitter of this type. The band wave 1 input from the P ₁₁ port is divided into in-phase and same amplitude by a magic T, and then passed through a band filter or filters a ₁ , a ₂ that provide non-pass characteristics for the band wave 2 input from the P ₂ port. , is excited by the coupling holes b ₁ and b ₂ and guided to the common output port P ₃ , where it becomes a polarized wave E _V1 . In exactly the same way, when the band wave 1 input from the _P12 port is led to the common output port _P5 , it becomes E _H1 which is orthogonal to _EV1 . binding hole
b ₁ , b ₂ , b ₃ , and b ₄ are placed exactly 90° apart around the common waveguide. On the other hand, the band wave 2 input from the input port P ₂ is affected by these coupling holes b ₁ to b ₄ , but the coupling holes are provided at 90° intervals, and the band wave 2 that is input from the input port P 2 has a high frequency that can be transmitted within the common waveguide. The next mode wave
When the TM ₀₁ and TE ₂₁ modes are used, the TE ₁₁ mode wave component orthogonal to the TE ₁₁ mode wave, which is the fundamental mode, is not generated. Therefore, it is possible to input the band wave 2 having polarization in any direction from the input port P ₂ and guide it to the common output port P ₃ . However, this configuration has the disadvantage that it is complicated and the adjustment is troublesome because it is necessary to divide the band wave 1 into two by the magic T when inputting it.

FIG. 2 is a block diagram showing another configuration example of a conventional polarization splitter, in which the band wave is connected to ports _P11 and _P12.
When the signals are output to port _P3 , which has been input from the source, the polarized waves are orthogonal to each other.

In the configuration example shown in FIG. 2, when the band waves 1 and 2 are to be led to the common output port _P3 as E _V1 , they are excited from the common port _P11 , and when they are to be led as E _H1 , they are excited from the common port _P12 . For this purpose, ports P ₁₁ and P ₁₂ require polarizers (synthesizers) 12 to combine band waves 1 and 2, but polarizers (synthesizers) 12 are required for ports P ₁₁ and P ₁₂ . Since the common waveguide can be excited at the same location, there is little deterioration of polarization and no magic T is required. However, in this configuration example, not only is the filter polarizer 12 required to combine the band waves 1 and 2, but also the ports P ₁₁ and P ₁₂ must simultaneously excite both band waves. 1
While it is more complex than the configuration example shown in the figure, it also has the disadvantage that adjustment is extremely troublesome.

On the other hand, in the configuration example shown in FIG.
The part where band wave 1 is transferred to the common waveguide is a coaxial line so that band wave 2 is not affected. Then, the band wave 2 is transmitted through the waveguide serving as its center conductor. Therefore, there is no need to provide a filter for blocking the coupling of band wave 2 to the port into which band wave 1 is input, and the port can be moved to a coaxial line. The band wave 1 that has been transmitted through the coaxial line and the band wave 2 that has been transmitted through the circular waveguide that is its center conductor are transferred to the corrugated circular waveguide section C. The impedance of the groove of this corrugated waveguide section C is inductive for band wave 1,
Since it is selected as capacitive for band wave 2,
In the band wave 1, the wall current increases and the energy distribution begins to surround the tube wall, so that a transition from a matched coaxial line to a waveguide line is performed. On the other hand, band wave 2 is affected by the corrugation in the opposite way to band wave 1, so there is less leakage to ports P ₁₁ and P ₁₂ , and the large circular waveguide that is the common line is more effective than the small circular waveguide that is the center conductor. Radio waves can be transferred to the tube well. Since this corrugated waveguide section C is symmetrical about the common circular waveguide axis, it has the characteristic that it can provide good polarization characteristics regardless of the direction of polarization of the band waves 1 and 2.

This invention has been made in view of the above-mentioned conventional situation, and the purpose of this invention is to solve the problem of the polarization demultiplexer shown in FIG. It is an object of the present invention to provide a novel polarization splitter that can realize characteristics similar to those obtained in a small size and with a simple structure.

The above object of the present invention is to connect a circular coaxial line having a circular waveguide as the center conductor and a circular waveguide having a common line as the outer circumferential conductor, and to generate a first frequency band wave from a portion of the circular coaxial line. In a polarization splitter in which a second frequency band wave having a higher frequency than the first band wave is transmitted to the central circular waveguide, the circular waveguide is excited and transmits a second frequency band wave having a higher frequency than the first band wave to the central circular waveguide. A multilayer dielectric filter is provided around the entire circumference between the center conductor and the outer conductor of the coaxial line, which serves as a pass band for waves in the first frequency band and a reflection area for waves in the second frequency band. This is achieved by a dual frequency band polarization demultiplexer.

Next, a preferred embodiment of this invention will be explained in detail with reference to the drawings.

FIG. 4 is a block diagram showing an embodiment of the present invention. That is, as shown in FIG. 4, a coaxial line is used for band wave 1, and a circular waveguide is used as the center conductor for band wave 2. By providing a dielectric multilayer filter (filter) d in the conversion section between the coaxial line and the circular waveguide line, the axial ratio of the polarized waves can be deteriorated without mutual interference between band waves 1 and 2. It leads to a common circular waveguide without any problems. To explain this embodiment with reference to the drawings, as shown in FIG. 4, a circular waveguide smaller than one of the common circular waveguides is inserted along the tube axis. A dielectric multilayer filter d is provided in the space between the tip of the inserted waveguide and the common circular waveguide. P ₁₁ , P ₁₂ connect band wave 1 to coupling hole b,
port for leading to the common circular waveguide via b′,
P ₂ is a port for exciting band wave 2,
The direction of polarization is arbitrary.

In the configuration shown in the figure, band wave 1 has a lower frequency than band wave 2. The dielectric multilayer filter d passes band 1 and does not pass band 2. Now, band wave 2 input from input port P ₂
is radiated into a common waveguide at the tip of the waveguide, which serves as the center conductor of the coaxial line. At this time, since the dielectric multilayer filter d has a non-pass band, a short-circuit surface is equivalently formed between it and the common waveguide. Therefore, by devising the position and structure of the dielectric multilayer filter d, it is possible to transfer it to a common circular waveguide without causing impedance mismatch. Since the dielectric multilayer filter d is rotationally symmetrical around the tube axis of the common waveguide, the polarization direction of the input wave from the input port _P2 is arbitrary, and its axial ratio is degraded in this conversion section. There's nothing to do. or,
There is also almost no generation of higher-order mode waves that degrade the axial ratio with respect to the frequency of band wave 2.

On the other hand, band wave 1 input from input port _P11
passes through the dielectric multilayer filter d and moves to the waveguide line. At this time, the diameter of the waveguide through which input port _P2 is transmitted must be selected so that it is in a non-transmission range for band wave 1. In addition, the dielectric multilayer filter d is composed of five dielectric layers in the case of this embodiment. It is necessary to design each time as a parameter.

The above operation is similar to that for band wave 2.
Since the large and small circular waveguides and dielectric multilayer filters are all rotationally symmetrical around the waveguide axis, even band 1 waves can be excited to have polarization in any direction. However, it does not cause deterioration of the axial ratio. Therefore, by providing another port _P12 orthogonal to port _P11 and further providing a partition plate e parallel to the polarized wave input from port _P11 , band wave 1 can also be excited from port _P12 . I can do it.

In the above explanation, Fig. 4 shows a case where the dielectric multilayer filter is a multilayer filter tilted with respect to the waveguide axis, but even if the filter has the structure shown in Fig. 5, the operating principle is completely the same as the above explanation. are the same.

From the above, for frequency band wave 1, the common waveguide is excited with two orthogonal polarizations, while for another higher frequency band wave 2, another waveguide with polarization in an arbitrary direction is excited. A simple orthogonal polarization splitter can be provided by a structure in which two orthogonal polarized waves can be transferred to a common waveguide without causing deterioration of the axial ratio in principle.

[Brief explanation of the drawing]

FIGS. 1A and 1B are an external view showing an example of a conventional polarization demultiplexer for the same purpose as the present invention; a perspective view of the internal configuration showing the position and arrangement of coupling holes and filters; FIG. 3 is a block diagram showing another example of the configuration of a conventional polarization duplexer, FIG. 3 is a diagram showing still another example of the configuration of a conventional polarization duplexer, and FIG. 4 is a block diagram of a polarization duplexer according to the present invention. FIG. 5 is a diagram showing another embodiment of the dielectric multilayer filter used in the present invention. 1, 2... Frequency band wave, 11... Polarization splitter capable of simultaneously feeding band wave 1 and band wave 2 with the same polarized wave, 12... For combining band wave 1 and band wave 2 Combiner (filter), P ₁₁ , P ₁₂ ... Input port for inputting band wave 1, P ₂ ... Input port for inputting band wave 2, P ₃ ... Common output port, a ₁
~a ₄ ... Filters all having the same characteristics to prevent band wave 2 from coupling, b, b', b ₁ ~b ₄ ...
Coupling hole, c... Corrugate conversion section, d... Dielectric multilayer filter, e... Partition plate provided in parallel to coupling hole b' at the center between the center conductor and the outer conductor of the coaxial line.

Claims (1)

[Claims] 1. A circular coaxial line with a circular waveguide as the center conductor and a circular waveguide with a common line as the outer circumferential conductor are joined, a first frequency band wave is excited from the circular coaxial line, and the central circular waveguide is excited. The waveguide has the first
In a polarization splitter in which a second frequency band wave having a higher frequency than the band wave of A polarization demultiplexer for dual frequency bands, characterized in that a multilayer dielectric filter is provided that serves as a pass band for waves in the first frequency band and a reflection area for waves in the second frequency band.