JPS639304A - Microwave propagation path - Google Patents

Abstract

PURPOSE:To decrease the transmission loss of a microwave by providing a circulator group connected in cascade to an output terminal of a broad band pass filter and a circulator group connected in cascade with other output terminals of the circulator and forming multi-stage for wave branching/ synthesizing constitution being the combination of the circulators and band pass filters. CONSTITUTION:The broad band pass filter 18 is a broad band pass filter passing waves whose frequencies are f11-f14, and the attenuation characteristic is shown in broken line 19. Thus, waves made incident in an input terminal A whose frequencies are F11-f14 and f21-f24 are branched into the frequencies f11-f14 and f21-f24 by the circulator 17 of the broad band pass filter 18. Then each frequency is branched by circulators 1-4, filters 9-12, circulators 5-8 and filters 13-16. In considering the wave of the frequency f24, the transmission loss is caused by 9 paths comprising the circulators 17 and 5-8, then the loss is less in comparison with conventional 16 paths' loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave propagation path in which a plurality of microwaves having different frequencies propagating on a transmission line are split into one or multiplexed and propagated.

[Prior Art] Conventionally, in order to separate or combine multiple microwaves with different frequencies, a bandpass filter and a circulator are combined, and the microwaves within the passband of the filter and the passband are combined. This configuration uses a circulator to split the microwaves from the outside and reflected by the filter.

A summary of this type of tiger rice is shown in Figure 3.

Although it is explained as a demultiplexing device N in FIG. 3, when used as a multiplexing device, it can be achieved by rotating the rotation direction of the circulator in the same figure in the opposite direction to the direction of the arrow in the same figure.
Since the operating principle is the same, its explanation will be omitted.

In FIG. 3, this branching device has circulators 1 to 8 arranged vertically bc+fi on the transmission line, and each circulator 1 to 8 has a different frequency band fll to f.
la, f'? +" f 2& are connected to each other.

Then, a different frequency from input terminal A to fIJlf
When a plurality of microwaves from 21 to f24 are propagated, these microwaves are first guided to the bandpass filter 9 via the circulator 1, but here, the frequency fll is
Only the microwaves passing through the filter 9 are separated, and the other microwaves are reflected and guided to the bandpass filter 10 via the circulator 1.2, where the microwaves with the frequency f12 are separated. only the signals are demultiplexed. Hereafter, in the same manner, f13. Microwaves of frequencies f14 and fil to f2a are separated.

[Problems to be solved] Here, in the conventional demultiplexing (multiplexing) system described above, the circulators are connected in series, so the number of circulators passing through varies depending on the frequency to be demultiplexed, resulting in insertion loss. For example, as shown in FIG. 2, the frequency f2
Since the 40 waves pass through all of the circulators 1 to 8, there is a large insertion loss. Therefore, the wave of frequency f24 has a higher transmission loss than the wave of frequency fll by 14 passages through the circulators.

Therefore, an object of the present invention is to provide a microwave propagation path that can reduce the transmission loss caused by passing through a circulator even when multiplexing or demultiplexing many frequencies over a wide frequency range. It is about providing.

[Means for Solving Problems] The present invention provides a method for splitting or combining a plurality of microwaves having different frequencies propagating on a transmission line and propagating them. A circulator inserted and connected in the middle of the line, a wide band pass filter connected to one output end of this circulator to pass microwaves of three or more frequencies, and a circulator connected in cascade to the output end of this wide band pass filter. a group of circulators connected vertically bc to other output ends of the circulators, and a group of bandpass filters that are connected to each of the circulator groups and pass frequencies in a predetermined range. .

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a consultation report of a device N according to an embodiment of the present invention.

In the figure, the microwave propagation path according to one embodiment is as follows:
A circulator 17 is inserted and connected in the middle of the transmission line 28 on which microwaves having a plurality of frequencies ftl~fla, f2+~f's propagate, and a circulator 17 is connected to one output end of this circulator to transmit microwaves of three or more frequencies. A broadband pass filter 18 to pass the filter 18, and circulators 1 to 4 connected vertically bc to the output end of the broadband pass filter 18.
The first circulator group 19 is connected to each of the first circulator group 19, and
A first band-pass filter group 21 is made up of band-pass filters 9 to 12 that pass the frequency of fz, and a first band-pass filter group 21 is made up of circulators 5 to 8 that are cascade-connected to the other output end of the circulator L7. 2 circulator groups 20;
A second band A filter group 22 includes band pass filters 13 to 16 connected to each of the second circulators t#20 and passing frequencies f21 to f24. .

Here, consider frequency distribution 1 as shown in FIG. 2 as the frequencies of fz''fzi and f21-f24.The wideband A filter 18 is a wideband filter l that passes waves of frequencies fll to f14. , the attenuation characteristics are as shown by the broken line 19. Therefore, the waves of frequencies fll to f(s) and waves of f21 to fzs incident on the input terminal A are filtered by the broadband pass filter 18 and the circulator 17. The waves are split into f-f14 and f21-f2g.Then, each frequency is divided into circulators 1-4 and filter 9.
~12 and circulators 5~8. Filters 13-16
The waves are separated by

If we consider the frequency &fzs wave here, it is the passage loss of 9 passages from circulator 17 and circulators 5 to 8, and compared to the IB passage when using the conventional demultiplexer shown in Fig. 3, In general, the wider the passband width of a band-pass filter, the lower the insertion loss, and as shown in the attenuation curve 23 in FIG. It has a wide band, and its insertion loss is small and can be ignored.

In addition, in FIG. 3, waves with frequencies f21 to f2s pass through circulators 1 to 4, so circulators 1 to 4
4 must be a wideband circulator that satisfies the required electrical characteristics in the front band from frequencies fll to fH in Figure 2, but for example, from 5.9 GHz to 7 GHz.
- IGHz wide frequency band circulators are generally 5.9GHz to 6.4GH2 or 6.4GHz.
Compared to narrow band circulators from GH/ to 7.1 GH, it has inferior electrical characteristics, such as high insertion loss, and therefore, the loss will further increase in the case of demultiplexing ``j<21'' in Figure 3. There are drawbacks.

On the other hand, in the case of the configuration example shown in FIG. 1 according to the present invention, only the circulator 17 needs to have a broadband circulator.
Circulators 1 to 4 and circulators 5 to 7 are
Narrow band circulators in the f-th to f-outlet and fz+"fzs frequency bands can be used, respectively, and circulators with good electrical characteristics such as low loss can be used.

In this way, according to this embodiment, the quasi-frequency demultiplexing configuration (
1st. The second circulator group 19°20 and the first circulator group 19°20.
Since the stage before the second band-pass filter group 21, 22) has a combination of a wide-band-pass filter 18 and a circulator 17 that commonly pass microwaves of at least three frequencies, Passage loss can be reduced.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

As described above, when this microwave propagation path is used as a multiplexing device, the rotation direction of each circulator shown in FIG. 1 may be set in the opposite direction to the direction of the arrow in the same figure.

[Effects of the Invention] As explained below, according to the present invention, by using a multi-stage demultiplexing or multiplexing configuration that combines a circulator and a bandpass filter, for example, in the case of demultiplexing, each demultiplexing Since the bandwidth required for the circulator at each stage becomes narrower as the demultiplexing stage progresses, it is difficult to reduce the insertion loss and to increase the cost, especially when demultiplexing into waves of many frequencies over a wide frequency range. This has the effect of reducing the number of broadband circulators.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a demultiplexer which is an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the distribution A8 of frequencies to be demultiplexed and attenuation characteristics, and Fig. 3 is a conventional demultiplexer. FIG. 17: Circulator 18: Broadband, 1[I filtering: 19.20: Circulator group

Claims (1)

[Claims] A circulator inserted and connected in the middle of a line on which a plurality of microwaves propagate in a microwave propagation path in which a plurality of microwaves having different frequencies propagating on a transmission line are propagated by splitting or combining them; and the circulator. a wide band pass filter connected to one output end to pass microwaves of two or more frequencies; a circulator group connected in cascade to the output end of the wide band pass filter; and a group of circulators connected in cascade to the other output end of the circulator. A microwave propagation path comprising a group of connected circulators and a group of bandpass filters connected to each of the circulator groups and passing a frequency setting in a predetermined range.