JPS5938722Y2 - Multiplexer/demultiplexer for microwave antennas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field This invention relates to a multiplexer-demultiplexer for microwave antennas, more particularly antennas for the transmission of telephone channels.

BACKGROUND OF THE INVENTION Increasing the density of wireless links requires the use of a larger number of antennas at communications central stations.

The space available for such an antenna on a support tower is of course limited, and therefore several frequency bands (V, H
The idea naturally arises that the polarization can be used).

Abbreviated as 3.6-4゜2 GHz and 5.9, respectively.
~6.4GHz, 6.4~7.1GHz, 1
4G for each frequency band from 0.7 to 11.7GHz
Hz + 6 GHz + 7 GHz.

It is described as a frequency band of 11 GHz.

Various solutions have been proposed in the past, one of which is a well-known multiplexer/demultiplexer for three frequency bands: 4 GHz and 6 GHz.

It can carry a frequency band of 11 GHz, and the energy in each frequency band is captured by a fully coupled directional coupler, with six directional couplers placed in series one behind the other, two for each frequency band. be done.

This solution cannot be applied when at least two of the frequency bands are close to each other, and it is difficult to perform band separation where the frequency bands are close to each other.

Another well-known multiplexer-demultiplexer is capable of processing two frequency bands (4 GHz, 6 GHz), in this case two polarizations for the 4 GHz frequency band and polarization transmission and reception for the 6 GHz frequency band. Two directional couplers of total coupling type in combination with a switch are used, and this solution, like the above method, also does not give good results when the two frequency bands are close to each other.

Furthermore, three frequency bands (4 GHz, 6 GHz
.

7GH2) Multiplexer demultiplexer adapted for sound processing is also known, which has a port for coupling to the antenna, a directional coupler system for the 6GHz and 7GHz frequency bands, and a polarization for the two 4HGz frequency bands. It is constructed by arranging in series a polarization transmitter/receiver switcher for separating the polarized waves.

Purpose of the invention The purpose of this invention is to solve these problems.

The multiplexer-demultiplexer according to this invention can operate in the same frequency band as the three frequency bands mentioned above, providing the benefit of excellent isolation or combination between different frequency bands.

Therefore, in this invention, the 6 GHz and 7 GHz frequency bands are processed at positions where the 4 GHz frequency band does not exist, and a structure of elements is provided to separate or double the 6 GHz and 7 GHz frequency bands. It will be done.

According to this invention, in order from the antenna input terminal side, a mode filter, a first polarization separation/mixing device, and a second polarization separation/mixing device are provided with two orthogonal output terminals that pass horizontal and vertical polarization frequencies, respectively. 4 GHz (3,4-4.2 GHz
), 6 GHz (5,9~6゜3 GHz) and 7 GHz (6゜4~7゜I GHz) in a multiplexer/demultiplexer for a microwave antenna, in which the mode filter is T
The first polarization separation/mixing device is configured to attenuate the E12 mode button and the 7M1□ mode, and is coupled at 90° to each other, and has a rectangular main waveguide and a secondary waveguide, respectively, for total coupling of the 4GHz band. The second polarization separation/mixing device is formed of a circular waveguide, and the second polarization separation/mixing device is coupled to the first polarization separation/mixing device via a square/circular converter. There is also provided a multiplexer/demultiplexer for a microwave antenna, characterized in that the two orthogonal output terminals are respectively coupled to two frequency separators that pass two bands of 6 GHz and 7 GHz.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be better understood and other features of the invention will become apparent from the following description of the drawings.

FIG. 1 schematically shows an offset cast-grain antenna equipped with a multiplexer/demultiplexer according to this invention.

The life 1, the auxiliary reflector 2 and the main reflector 3 are shown in cross-section, and the multiplexer/demultiplexer 5 is shown in side view.

The multiplexer-demultiplexer 5 has a port coupled to lifetime 1 and the other 6 ports 4V.

The (7) ports will be described later with reference to other drawings.

1, only the multiplexer/demultiplexer of the transmitting and/or receiving circuitry of the antenna is shown; the other circuitry is conventional in design.

As a display example, the antenna shown in Figure 1 has a height of 5 m,
Also, from the viewpoint of performance, it is equivalent to a horn reflector type antenna with a height of 1077Z, and the multiplexer/demultiplexer 5 is approximately 2.5 m.

This assembly can be glued to the upper part of the tower, which also mounts all the circuitry and equipment necessary for the operation of the antenna, so that the connections between these various elements are not parasitic due to the length of the elements. or cause any other interference.

FIG. 2 shows the multiplexer/demultiplexer 5 shown in FIG. 1 in more detail.

The multiplexer-demultiplexer considered as an example in this description covers the entire frequency plane of the 4 GHz CCIR frequency for beams with 960 channels per channel group, and the entire frequency plane of the 6 GHz CCIR frequency band for beams with 1800 channels per channel group. Half of the plane and half of the full frequency plane of the 7 GHz CCIR frequency band for a beam of 2700 channels per channel group are activated, thus approximately 40,000 half telephone channels are connected to this multiplexer device. Can pass through multiplexer.

That is, as mentioned above in the 3.6-4.2 GHz frequency band there are 960 channels per channel group, and the multiplexer-demultiplexer passes only 3 of the 6 channel groups, so 960X3=
This results in 2,880 telephone channels.

Also, in the 5,9-6.4 subband, there are 1800 channels per channel group, and the multiplexer/demultiplexer passes only 4 of the 8 channel groups, so the number of telephone channels is 1soox4=72
It becomes 00.

Furthermore, in the 6.4-7.1 GHz subband, there are 2700 channels in a channel group, and the multiplexer/demultiplexer passes only 4 out of 8 channel groups, so the number of telephone channels is 2700.
It becomes X410800.

Therefore, the total number of telephone channels that can pass through the multiplexer/demultiplexer is 2880 + 7200 + 108
00=20880, i.e. about 20 as mentioned above.
This means 000.

The multiplexer/demultiplexer shown in FIG. 2 will be considered as a demultiplexer, that is, the one before the antenna will be explained.

This device includes a port A, a first coupling device 10, a first directional coupler 12, a second directional coupler 13, a second coupling device 14, and a mode converter.
ns-ducer) 15 and frequency separator 20.30
It consists of.

3.6-4.
All vertically and horizontally polarized signals for the frequency band 2 GHz and 6.2-6°4 GHz)- and 6.7-
A common input for vertically and horizontally polarized signals in the 7° IGHz frequency band.

A mode filter is coupled to the circular-to-square converting section, that is, the first coupling device 10, and has the function of suppressing the possibly occurring TE12 mode and TM1□ mode, and is constituted by a nickel-chromium coated glass resistor.

The first directional coupler 12 is coupled to the first coupling device 10 and is composed of a main waveguide 12a having a rectangular cross section and passing through all operating frequencies of the antenna, and a secondary waveguide 12b provided with an output port 4Ve. The electromagnetic coupling between the main waveguide 12a and the secondary waveguide 12b is performed through a hole formed in the common wall of the main waveguide 12a and the secondary waveguide 12b.

The first directional coupler 12 is adapted to transmit the entire vertically polarized signal in the 4 GHz frequency band applied through the first coupler 10 to the output of the demultiplexer (4V).

The second directional coupler 13 is the same as the first directional coupler 12 and is disposed continuously with the main wave pipe 13ak of the first directional coupler 12, and is connected to the first and second directional couplers. main waveguide 12a of the device 12.13.

13a have a common axis and are rotated by 90° with respect to each other around this axis, so that the output capacitor (4H) of the secondary waveguide 13b of the second directional coupler 13 is horizontal in the 4 GHz frequency band. This is the output for polarization.

The square-to-circular conversion section, ie, the second coupling device 14, is coupled to the main waveguide 13a of the second directional coupler 13.

The mode converter 15 has an input port coupled to the second coupling device 14 and two polarization ports (H, V) and operates as a polarization separator for demultiplexing purposes.

This polarization splitter 15 has two polarized waves (H, V).
Two linearly polarized waves H and V'i within a band of 5.9-7.1 GHz are transmitted.

A frequency separator 20 is coupled to the polarization port ()H of the mode converter 15, the frequency separator 20 having a first end coupled to the polarization port ()H and connected to a matching network for a band of 7 GHz. a waveguide 21 with a tuned compensation stub 22;
The first of the three ports is coupled to the second end of the waveguide 21 via the Y junction 23, and each Y
These filters have two filters 24,25e with isolators coupled to the second and third ports of the junction 23 and adapted to improve the impedance matching to the inputs facing the Y-junction 23. 24.25 corresponds to 6, 7-7° IGHz sub-frequency range, respectively corresponding to 2700 channels per channel group and 6, corresponding to 1800 channels per channel group, respectively.
The terminals of the filters 24, 25, which are tuned to the 2-6.4 GHz sub-frequency range, and opposite the Y-junction 33, are tuned to the 6.7-7° IGHz and 6.2-6.4 GHz sub-frequency ranges of the demultiplexer, respectively. Output ports 7H and 6H, which are outputs for horizontal polarization of the station wave number, are configured.

The frequency separator 30 is coupled to the polarization port (V) of the mode converter 15 and is constituted by elements corresponding to those of the frequency separator 20.

The output port, which is the output for vertical polarization of the 6゜26.4GHz h and 6゜7-7゜I GHz sidebands, is 6V.
.

The matching network and stub 32 for the waveguide 31 are tuned to a frequency band of 5°9-6.7 GHz, and the filters 34, 35 each have a frequency band of 2700 channels per channel group. 5, corresponding to a beam with a side frequency range of 6°4-6.7 GHz and 1800 channels per channel group;
6 GHz, tuned to the side frequency range of 9-6.2 GHz and derived by frequency separators 20° and 30, respectively
Relatively high frequency range of the 7 GHz band and 6 GHz
z, the relatively lower frequency range of the 7GHz band is 6GHz
z, resulting in good performance in links utilizing this multiplexer-demultiplexer despite the approximation of the 7 GHz band.

FIG. 3 schematically shows the frequency separator 20 shown in FIG.

In the explanation of FIG. 2, the matching network described in relation to the frequency separator/mixer is designated by the same reference numeral 21 as the waveguide to which it is coupled.

Also, a compensation stub 22, a Y-junction 23, a filter 24゜2
5, output port doors H, 6H, and port B connected to the polarization splitter 15 in FIG.

For clarity, the multiplexer-demultiplexer will be described as being used only for demultiplexing.

As is well known, all elements that effect separation can be used in reverse for demultiplexing.

However, in normal operation commensurate with a well-characterized link, the antenna is preferably used for simultaneous multiplexing and demultiplexing, and one of the frequency separators 20, 30 is a demultiplexing frequency separator. and the other is used as a multiplexing frequency mixer, thereby allowing the first . Second
Each of the directional couplers 12.13 can be used for transmission or reception without affecting the characteristics of the link, regardless of how the other directional coupler is used.

The results listed below correspond to this type of operation of a multiplexer-demultiplexer.

The frequency separator 20 has a standing wave ratio of 1°05 and a frequency of 6 GHz.
.

Covers the frequency range of the 7GHz band.

Filter 2 used for relatively high frequency range
4.25 has 10 cavities and has a frequency of 6°4 GHz,
40 d for frequencies approximately equally spaced from 6°7 GHz
T s cheby resulting in attenuation equal to or better than 40 dB and excellent definition of the filter shorting plane
s ch ef f cavity filter.

The transmission loss ranges between 0.002dB and 0.4dB,
Further, the variation in group delay time is 0.005 ns or less.

Similar results can be obtained using the Butterworth type filter 34.
5.9-6.2 GHz using °35, 6.4-
obtained for a relatively low frequency of 6.7 GHz.

As is obvious, the invention is not limited to the multiplexer-demultiplexer described here; for example, one of the frequency separators may be used to transmit a single frequency band, and two filters of this frequency separator may be used to transmit a single frequency band. An alternative embodiment could be used in which one of the two is replaced by a matched load, and the coupling of the frequency separators 20 and 30 could be switched.

Effects of the invention As explained above, this invention not only makes it possible to obtain good splitting and combining between different frequency bands, but also greatly increases the capacity in terms of the number of telephone channels that can pass through this device. can.

This idea can be implemented as follows.

(1) Each waveguide 21.31 has a matching network.

(2) a third bandpass filter 25 button whose first port is coupled to one of two other ports of the first Y-junction 23;
A fourth bandpass filter 35 is provided whose port is coupled to one of the two other ports of the second Y-junction 33; Third frequency band (5,9-6,4GHz, 6.4-7.
1 GHz) are each subdivided into a relatively low frequency range and a relatively high frequency range; Second. Third. The fourth bandpass filters 24, 34, 25, and 35 respectively cover a relatively low side frequency range of the second frequency band, a relatively high side frequency range of the second frequency band, and a relatively low side frequency range of the third frequency band. and the relatively higher frequency range of the second frequency band.

(3) First. The second coupling devices 10.14 each have a circular
It is a square and a square/circular converter.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an antenna having a multiplexer/demultiplexer according to the invention, FIG. 2 is a detailed diagram of the multiplexer/demultiplexer of the antenna shown in FIG. 1, and FIG. 3 is a diagram of one of the elements shown in FIG. It is a block diagram. In the drawing, 1 is the lifetime, 2 is the auxiliary reflector, 3 is the main reflector, 5 is the multiplexer/demultiplexer, A, B, 4
V, 4H, 6V, 7V, 6H. 7H is a port, 10 is a first coupling device (circular/square conversion section), 12 is a first directional coupler, 13 is a second directional coupler, 14 is a second coupling device (square/circular conversion section), 15 is a positive mode converter, 20.30 is a frequency separator, 21.31
is a waveguide, 22.32 is a compensation stub, 23.33 is a Y-junction, and 24°25.34.35 is a bandpass filter.

Claims (1)

[Scope of utility model registration request] Mode filter 10, first mode filter in order from the antenna input terminal side
The polarization splitter mixer has a second polarization splitter mixer with two orthogonal output terminals V, H'i passing the horizontal and vertical polarization frequencies, respectively. 3.4~4.2 GHz),
6 GHz (5,9-6.4 GHz) and 7 G
The mode filter 10 is suitable for a multiplexer/demultiplexer for a microwave antenna for separating a frequency band of Hz (6°4 to 7.1 GHz).
2 mode and TM12 mode are attenuated;
Two series direct couplers 12. The first polarization separation/mixing devices are coupled at 90 degrees to each other and are composed of a rectangular main waveguide and a secondary waveguide for full coupling of the 4 GHz band.
13, the second polarization separation/mixing device is made up of a circular waveguide 15, and is coupled to the first polarization separation/mixing device via a rectangular/circular converter 14, and the two orthogonal A multiplexer/demultiplexer for a microwave antenna, characterized in that output terminals V and (2) are respectively coupled to two frequency separators 20 and 30 that pass two bands of 6 GHz and 7 GHz.