JPS603241B2 - duplexer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a microwave splitter that splits propagating waves in multiple frequency bands into waves in a high frequency band and waves in a low frequency band.

Here, for convenience of explanation, a high frequency wave is referred to as fH, a low frequency band wave is referred to as fL, and a duplexer for fM and fL will be described.

FIG. 1 shows a cutaway side view of a conventional duplexer.

In the figure, 1 is a shared circular waveguide, 2 is a partition for forming a corrugated groove in the shared circular waveguide 1, 3 is a corrugated groove formed by the partition 2, 4 is a dedicated circular waveguide, and 5 is a coupling 6 is a rectangular waveguide connected via the coupling hole 5 provided in the common circular waveguide 1; 7 is a low-pass waffle iron filter provided in the rectangular waveguide 6; 8 is a A coaxial line type polarization splitter consisting of a rectangular waveguide 6, a Watsuful iron filter 7, a coupling hole 5, a common circular waveguide 1, and a dedicated circular waveguide 4, 9 is a dedicated circular waveguide. A rectangular waveguide provided orthogonally to the dedicated circular waveguide 4; 10 is a rectangular waveguide provided coaxially with the dedicated circular waveguide 4; 11 is a shorting plate; 12 is a rectangular waveguide 9;
．． 10, a circular waveguide polarization splitter composed of a coupling hole 5;
14 is a coaxial line composed of a common circular waveguide 1 and a dedicated circular waveguide 4, and 13 is a post-shaped low-pass filter provided on the coaxial line base 14 to reflect the fH wave. Before explaining the operating principle of the duplexer shown in FIG. 1, the operation of the corrugated groove 3 will be explained to the extent necessary for explaining the present invention. If the interval between the corrugated grooves 3 is sufficiently small compared to the wavelength of the wave propagating in the shared circular waveguide 1, the corrugated grooves 3
exhibits capacitive susceptance at frequencies where the depth of the corrugated grooves 3 is between I/4 and ^/2, and exhibits inductive susceptance at frequencies where the depth of the corrugated grooves 3 is shallower than ^/4.

Here ^ is the free space wavelength. Now, the madmitance Yc exhibited by the corrugated groove 3 is distributed in series with the transmission line when expressed as an equivalent circuit.

Therefore, if the depth of corrugated book 3 is d, then ^/
When d<^/2, Yc/i20, and the phase velocity of the waveguide section provided with the corrugated groove 3 becomes faster than the phase velocity of the circular waveguide beam.

Further, when ^/4>d, Yc/j<0, and the phase velocity of the waveguide section provided with the corrugated groove 3 becomes slower than the phase velocity of the circular waveguide.

As the phase velocity decreases, the propagating wave begins to exhibit the characteristics of a so-called surface wave.

That is, most of the energy of the propagating wave is concentrated at the entrance of the corrugated groove 3, and is reduced at the center of the waveguide.
Naturally, the opposite phenomenon occurs when the phase velocity is high. Now, if we choose the depth of the corrugated groove 3 so that fH is Yc/20 and fL is Yc/i<0, the waves of fH and fL incident on the common circular waveguide 1 will pass through the corrugated groove. 3, the energy of the wave fL is concentrated at the entrance of the corrugated groove 3, and the energy of the wave fH is concentrated at the tube axis and propagated.

Therefore, if the tip of the dedicated circular waveguide 4 is installed in the corrugated groove 3 of the shared circular waveguide 1, the fH wave will be split into the dedicated circular waveguide 4, and the fL wave will be split into the coaxial line 14. be waved.

At this time, since the dedicated circular waveguide 4 is designed to exhibit a shearing characteristic for the fL wave, the fL wave is transmitted to the circular waveguide corner splitter 12 which is the output end of fH. square waveguide 9
, 10.

However, some of the power of the fH wave leaks into the coaxial line 14 through which the fL wave propagates, and leaks into the rectangular waveguide 6 of the coaxial polarization splitter 8, which is the output end of fL. A shaped low-pass filter 13 is provided.

In this way, in the conventional duplexer shown in FIG. 1, the waves fL and fH incident on the common circular waveguide 1 are caused by the action of the corrugated groove 3 so that the wave of fL follows the entrance of the corrugated groove 3. The wave of fH propagates to the coaxial line 14, and the wave of fH propagates concentrated in the tube shaft portion, and is split into the dedicated circular waveguide 4, respectively.

Thereafter, the waves fL and fH are transferred to a branch rectangular waveguide 6 of each polarization splitter according to the state of the incident polarization by a coaxial polarization splitter 8 and a circular waveguide polarization splitter 12, respectively. ,9,
One river is waved. However, in conventional duplexers,
Since the post-type low-pass filter 3 is effective only for the fundamental mode wave of the fH waves leaked into the coaxial line 14, the waffle iron filter 7 is used as a filter for higher-order mode waves. Rectangular waveguide 6
Therefore, the structure of the coaxial polarization splitter 8 becomes complicated, and it is difficult to obtain good matching.

In addition, in order to branch the fH wave into the dedicated circular waveguide 4 while obtaining good matching, a dedicated circular waveguide 4 with a large inner diameter is required, but increasing the inner diameter will have an effect on the fL wave. Therefore, the inner diameter of the dedicated circular waveguide 4 could not be made sufficiently large, and there was a drawback that reflection at the tip of the dedicated circular waveguide 4 was large.

In order to eliminate these drawbacks, the present invention provides a coaxial line 14
The corrugated groove 3 provided in the section is changed to a waffle iron type filter, and a corrugated groove is newly provided on the inner wall of the dedicated circular waveguide 4.The drawings will be described in detail below. FIG. 2 shows an embodiment of the invention.

Further, FIG. 3 shows a sectional view taken along line A-A' in FIG. 2 to clarify the foundation structure. Compared to the secondary branching filter shown in FIG. is deformed into the shape shown in FIG. 3 to form a coaxial line type waffle iron filter, and the inner wall of the dedicated circular waveguide 4 is
A feature is that a corrugated groove 3 is newly provided in which Yc exhibits an inductive susceptance with respect to waves of .

In the duplexer embodying the present invention, a waffle iron filter 7 in the form of a coaxial line acts on the fH wave leaked into the coaxial line 14.

Since this waffle iron filter 7 exhibits a shearing characteristic for all mode waves of the fH wave, the rectangular waveguide of the coaxial line type polarization splitter 8 is used as shown in the conventional invention shown in FIG. There is no need to provide a waffle iron filler in 6. Therefore, the coaxial line type polarization splitter 8 that separates the wave of fL becomes simple, and matching is easily obtained and a good V
SWR characteristics can be obtained. Further, in the embodiment of the present invention shown in FIG. 2, a corrugated groove 3 in which Yc exhibits an inductive susceptance to waves of fH is provided in the dedicated circular waveguide 4.

The operating principle of this corrugated groove 3 is the same as that of the corrugated groove 3 provided in the shared circular waveguide 1. Therefore, by appropriately selecting the depth of the corrugated waveguide 3, it is possible to increase the amount of energy of the fH wave propagating through the dedicated circular waveguide 4 through the trajectories compared to the case of a circular waveguide. I can do it.

This has the effect of equivalently increasing the inner diameter of the dedicated circular waveguide 4. Therefore, compared to conventional duplexers,
The energy of the fH wave propagating through the common circular waveguide 1 provided with the corrugated groove 3 and concentrated in the tube axis is more easily divided into the dedicated circular waveguide 4 provided with the corrugated groove 3. As a result, the VSWR characteristics for fH waves at the tip of the dedicated circular waveguide 4 can be improved.

Although the above description has been made regarding two frequency bands, fL and fH, it is clear that the present invention is not limited to this, but can also be applied to cases where fL and fH include waves in multiple frequency bands. It is.

As described above, in the duplexer according to the present invention, the coaxial line type waffle iron filter 7 provided in the coaxial line 14 portion simplifies the structure of the equal line type polarized duplexer 8 and improves the VSWR characteristic. There is an advantage that it can be improved, and that the corrugated groove 3 provided in the dedicated circular waveguide 4 can improve the VSWR characteristic of the tip of the dedicated circular waveguide 4.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of a conventional duplexer, FIG. 2 is a cutaway side view showing an embodiment of the present invention, and FIG. 3 is a cutaway side view of a conventional duplexer.
It is an A' sectional view. In the figure, 1' is a common circular waveguide, 2 is a partition wall of a corrugated groove, 3 is a corrugated groove, 4 is a dedicated circular waveguide, 7 is a waffle iron filter, 8 is a coaxial line type polarization splitter, 12 1 is a circular waveguide type polarization splitter, 13 is a post-type low-pass filter, and 14 is a coaxial line. In the drawings, the same or corresponding parts are denoted by the same reference numerals. Many 1 drawings Many Z drawings Mi drawings

Claims (1)

[Claims] 1 A circular waveguide dedicated to high frequency bands that propagates waves in a high frequency band is installed concentrically within a shared waveguide that propagates waves in multiple frequency bands, and the vicinity of the tip of this dedicated circular waveguide is located By providing multiple corrugated grooves in the shared circular waveguide section, waves in the high frequency band are placed in a dedicated circular waveguide, while waves in the low frequency band are configured in the shared circular waveguide and the dedicated waveguide. A branching filter for branching into a coaxial line, characterized in that the partition wall of the corrugated groove located in the coaxial line part is a Watsuful iron filter, and the inner wall of the dedicated waveguide is provided with a corrugated groove. vessel.