JPS6129566B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a band-sharing duplexer used in a microwave antenna system.

For convenience of explanation, we will use the high frequency band _H.
A case will be explained in which the waves of L and the waves of the low frequency band _L are separated using a branch waveguide. First, the function of a conventional band-sharing demultiplexer will be explained in detail.

Figure 1 shows the configuration of a conventional band-sharing duplexer. In the figure, 1 is a circular waveguide, 2 is a circular tapered waveguide, 3 is a filter, 4 is a rectangular waveguide, and 5 is a filter. Vessel 3
and a rectangular waveguide 4;
is a coupling hole elongated in the tube axis direction of the circular waveguide 1 provided in the partition wall between the branch waveguide line 5 and the circular waveguide 1.

In this band-sharing splitter, the circular tapered waveguide 2 allows _{the H} wave to propagate but _{the L} wave is slightly cut off, and the filter 3 allows _{the L} wave to propagate. However, it is designed to cut off _H waves.

Further, the coupling hole 6 is formed in the circumferential direction of the circular waveguide 1.
Two pieces are provided facing each other at positions rotated 180 degrees.

Now, the frequencies _L and _H , which are the fundamental mode waves (TE ₁₁ mode) of the circular waveguide 1, are connected to the terminal 1 in Fig. 1.
Considering the _case where _a wave of
It shall be possible to combine with.

First, we will discuss the propagation of _{the L} wave. Part of
_{The L} wave is coupled to the coupling hole 6 and propagated to the branch waveguide 5, but the other _L waves reach the circular taper waveguide 2 and are completely reflected due to the cross-section characteristics of the circular taper waveguide. be done. At this time, if the size of the coupling hole 6 and the distance between the circular tapered waveguide 2 and the coupling hole 6 are appropriately selected, all the waves of _L will be transmitted to the branch waveguide 5.
It is split into two waves.

Next, we will discuss the propagation of _{the H} wave. Similar to the _L wave, a part of _{the H} wave is coupled to the branch waveguide line 5 through the coupling hole 6, but in this band-sharing splitter, a filter provided in the branch waveguide line 5 is used. It is all reflected by vessel 3. By providing this filter 3 as close to the coupling hole 6 as possible, the coupling hole 6 can be equivalently short-circuited for _H waves. As a result, all the waves of _H propagate through the circular tapered waveguide 2 and reach the terminal.

Therefore, _{the L} and _H waves incident from the terminal are split into _{an L} wave at the terminal and _{an H} wave at the terminal.

In this band-sharing splitter, it is necessary that the polarization plane of the _L wave has the relationship shown in Fig. 2 with respect to the coupling hole 6, but when splitting _{the L} wave with an arbitrary polarization plane, Four branch waveguide lines 5 may be provided at intervals of 90 degrees in the circumferential direction of the circular waveguide 1. Note that in Fig. 2, A is the line of electric force.

FIG. 3 shows an example of the configuration of a conventional band-sharing demultiplexer capable of demultiplexing the above-mentioned wave of arbitrary polarization plane.

In both of the band-sharing duplexers shown in FIGS. 1 and 3, the circular waveguide 1 and the branch waveguide 5 are connected via a coupling hole 6, but as shown in FIG. Separation can also be achieved by using a coaxial line 7 as the branch waveguide line 5 and coupling the circular waveguide 1 and the coaxial line 6 with a probe 8 attached to the center conductor of the coaxial line 7.

However, the conventional coupling hole 6 as shown in Figs.
In a duplexer that demultiplexes signals via a
The structure is complex and there are difficulties in workability. Also, the fourth
In the demultiplexer that demultiplexes the waves through the probe 8 as shown in the figure, in order to demultiplex _{the L} wave, the probe 8 must be inserted deep into the circular waveguide 1 and in a position where the electric field is strong. Therefore, it has a drawback that it has a strong influence on _{the H} wave of the probe 8, and cannot be applied especially when the power of _{the H} wave is large.

In order to eliminate these drawbacks, the present invention provides the branch waveguide line 5 in a cruciform waveguide, and will be described in detail below with reference to the drawings.

First, the outline of a cruciform waveguide will be explained. FIG. 5 shows a cruciform waveguide. This waveguide has two orthogonal polarized waves V shown by solid lines and broken lines in the figure, respectively.
B, polarized waves H and C can be propagated. Therefore, like the circular waveguide 1, this waveguide can propagate arbitrary polarized waves. In addition, the characteristics of a cruciform waveguide are that when excited considering the symmetry of the electromagnetic field, the shearing frequency of the fundamental wave and the shedding frequency of higher-order mode waves that are likely to be generated due to the excitation of the fundamental wave. Since the distance between the waveguide 1 and the circular waveguide 1 is much wider than that in the case of the circular waveguide 1, there is an advantage that the frequency band in which only the fundamental wave can be excited is wide.

FIG. 6 shows an embodiment of the present invention. In the figure,
1, 3, 5, and 7 are the same as in Fig. 4, 9 and 10 are cruciform waveguides, 11 is a converter between a cruciform waveguide and a circular waveguide 1, and 12 is a cruciform taper waveguide. tube, 13
is a matching element for _H waves. Cross-sectional views along lines AA, BB, and CC in FIG. 6 are shown corresponding to FIGS. 7a, b, and c, respectively.

In this invention, as shown in FIG. 7b,
A coaxial line 7 is used as the branch waveguide line 5 provided in the cruciform waveguide 9, and a coaxial filter 3 is connected to the cruciform waveguide 9 and propagates only _{the L} wave.
is provided. Further, one end of the inner conductor of the coaxial line 7 on the cruciform waveguide 9 side is fixed to the tube wall of the cruciform waveguide 9 on the extension line, and the branch waveguide 5 and the cruciform waveguide 9 are connected to each other. are mainly coupled by magnetic fields. This configuration is commonly known as coaxial
It is almost similar to a waveguide transducer.

In addition, the cross-shaped tapered waveguide 12, like a conventional band-sharing splitter, cuts _{the L} wave, but
_H waves are designed to pass through.

As described above, the present invention shown in FIG. 6 is equipped with a filter 3 having the same functions as a conventional band-sharing demultiplexer, a tapered waveguide 12, and a means for coupling to the branch waveguide 5. , incident from the terminal in Figure 6
Of _{the L} and _H waves, _{the L} wave can all be branched to the terminal by adjusting the mounting positions of the cross-shaped tapered waveguide 12 and the branch waveguide 5.

Further, _{the H} wave can propagate to the terminal without leaking into the branch waveguide line 5 due to the action of the filter 3.

In addition, in this invention, since _{the H} wave is partially reflected by the coupling part between the branch waveguide line 5 and the cruciform waveguide 9, the cruciform waveguide is small in size and only _{the H} wave propagates. By providing the matching element 13 in the 10th section, reflected waves are reduced.

The above describes a duplexer in which the circular waveguide 1 is converted into a cross-shaped waveguide 9. However, the present invention is not limited to this, and a square waveguide may be used instead of the circular waveguide 1. It's okay.

As described above, since the band-sharing duplexer according to the present invention uses the cruciform waveguide 9, FIGS.
Compared to the band-sharing duplexer shown in the figure, a rectangular waveguide 4 is connected orthogonally to the circular waveguide 1 via the coupling hole 6.
Since there is no need to attach a wire, it has the advantage that it can be easily machined by electroforming. In addition, compared to a band-sharing splitter as shown in _FIG . It has the advantage of being able to be used even when the transmission power of _{the H} wave is large because it can be attached to the main body.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway schematic diagram of a conventional band-sharing demultiplexer, Figure 2 is an explanatory diagram showing the relationship between electric field distribution and coupling hole position, and Figure 3 is an arbitrary polarized _L wave splitter. A schematic configuration diagram of a conventional band-sharing demultiplexer that can
Fig. 4 is a partially cutaway structural diagram of a conventional band-sharing duplexer using a coaxial line as the branch waveguide, Fig. 5 is an explanatory diagram showing the lines of electric force in a cruciform waveguide, and Fig. 6 7 is a schematic configuration diagram showing one embodiment of the present invention, and FIG. 7 is a sectional view showing the cross-sectional shape of FIG. 6. In the figure, 1 is a circular waveguide, 2 is a circular tapered waveguide, 3 is a filter, 5 is a branch waveguide, 9 is a cruciform waveguide, 11 is a converter, and 12 is a cruciform taper guide. It is a wave tube. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] 1. In a duplexer that is shared by multiple frequency bands, the first
a circular waveguide or a square waveguide; a first cross-shaped waveguide through which waves in the plurality of frequency bands can propagate; and a first cross-shaped waveguide through which waves in the plurality of frequency bands can propagate, and only waves in a high frequency band among the waves in the plurality of frequency bands can propagate. a second cruciform waveguide, a second circular waveguide or a square waveguide through which only waves in the high frequency band can propagate;
a converter that connects a circular waveguide or a square waveguide with the first cruciform waveguide; and a converter that connects the first cruciform waveguide with the second cruciform waveguide. a cruciform tapered waveguide, a transducer connecting the second cruciform waveguide and the second circular waveguide or the square waveguide, and a low-pass filter. A band-sharing duplexer comprising: a branch waveguide, and the branch waveguide is coupled to the first cruciform waveguide.