JPS62122302A - Branching filter - Google Patents

Abstract

PURPOSE:To limit the transmission power by providing a step conversion part giving matching between an electromagnetic wave of a low frequency band and an electromagnetic wave of a high frequency band to a face opposite to a branch waveguide at the joint between a main waveguide and a sub waveguide so as to eliminate the necessity of a band-pass filter. CONSTITUTION:A branch waveguide 3 including a band-pass filter 4 is connected to one face of the main waveguide 1 near the joint between the main waveguide 1 and the sub waveguide 2. The step conversion part 5 gives a matching between an electromagnetic wave of a low frequency band and an electromagnetic wave of a high frequency hand while being provided at a face opposite to the branch waveguide 3 at the joint between the main waveguide 1 and the sub waveguide 2. The length of the step conversion part 5 is selected nearly as lambdag2/4, the reflection at the joint between the main waveguide 1 and the sub waveguide 2 is eliminated to a transmission wave f2, the matching is given also to a reception wave f1 and has a characteristic so that the reception wave f1 is led efficiently to the branch waveguide 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] Misaki II relates to a branching filter for branching electromagnetic waves of the same polarization in multiple frequency bands.

[Conventional Techniques] Conventionally, as this type of duplexer, a configuration as shown in FIG. 2 has been adopted. That is, a main wave tube l that introduces low-frequency electromagnetic waves f- and high-frequency electromagnetic waves f2, ', V, a bandpass filter 4 that passes the magnetic waves f+ and blocks the electromagnetic waves f2, 'il+ , magnetic wave fl
A bandpass filter 6 that blocks the electromagnetic wave f2 and passes the electromagnetic wave f2.
, the branch waveguide 7 that transmits the electromagnetic wave f1, and the electromagnetic wave f?
It was composed of a branch waveguide 8 that transmits.

Now, if the low frequency '+lj magnetic wave fl is the received wave and the high frequency electromagnetic wave f2 is the transmitted wave, then the received wave f! introduced into the L waveguide l! is reflected by the bandpass filter 6 and taken out through the bandpass filter 4. Further, the transmitted wave f2 that has passed through the five-branch waveguide 8 and the band-pass filter 4 is guided to the main waveguide 1 by the band-pass filter 4 without leaking to the branch waveguide 7.

According to the conventional duplexer described in [Problems to be solved by N IjI], a 4-if bandpass filter 6 is required in the path for passing the transmitted wave f2, and arcing occurs when high power is passed. Therefore, there was a drawback that the transmission power was subject to an 11 limit.

The present invention has been made in view of the problems listed in item L, and aims to provide a duplexer that eliminates the need for a bandpass filter and is not limited by the transmission power.

[Means for Solving the Problems] In order to achieve the above object, the duplexer of the present invention includes a rectangular main wave tube that propagates electromagnetic waves of the same polarization in multiple frequency bands, and a rectangular main wave tube that propagates electromagnetic waves of the same polarization in multiple frequency bands. a branch waveguide connected in series with the main waveguide and including a bandpass filter that passes only low frequency A-band electromagnetic waves; The above-mentioned branch at the connection between the secondary and q-wave tubes and the aforementioned waveguide and the secondary 4-wave tube; matching for electromagnetic waves in a low frequency band and electromagnetic waves in a high frequency band provided on the opposite side of the q-wave tube. It consists of a stay that calculates γ, and a conversion section.

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

In Figure 1, l is the main waveguide, and 2 is a sub-waveguide connected to the main waveguides l and 6 and 1, which has a shape that cuts off low-frequency electromagnetic waves and allows high-frequency electromagnetic waves to pass through. be. 3 is a branch waveguide that includes an area filter 4 that allows only low-frequency electromagnetic waves to pass ifi; It is connected. 5 is a step conversion section, which converts the leading wave erF
Matching is given to the submerged low frequency band electromagnetic waves and the high frequency band electromagnetic waves on the surface opposite to the branch waveguide 3 at the connecting portion between the sub waveguide 2 and the sub waveguide 2. This step converter 5 has a length of about λg2/4, and eliminates reflection at the connection between the main waveguide l and the sub-waveguide 2 for the transmitted wave f2, and converts the received wave fl It also has a characteristic that the received wave f1 is efficiently guided to the branching waveguide 3 (here, λg2 is the internal wavelength of f).

Now, the transmitted wave f? to the sub waveguide 2? is introduced, the transmitted wave f2 is transmitted to the main waveguide 1 at the step converter 5 without reflection. In addition, the received wave f1 provided in the main wave tube l
The received wave f1 passes through the demultiplexer, and the transmitted wave f2
The bandpass filter 4 that blocks the waves of approximately λg2 from the demultiplexing section
Since they are provided at a distance of /2, the branching section forms an electrical short-circuit surface for the transmitted wave f2 and prevents the transmitted wave f2 from coupling to the receiving terminal. On the contrary, the received wave fl introduced into the main waveguide 1 is given a short-circuit surface by the step converter 5 and at the same time is matched with the duplexer and guided to the branch waveguide 3.

[Effects of the Invention] As explained above, according to the duplexer of the present invention, the band-pass filter that was conventionally required can be eliminated.

Limitations on transmission power can be eliminated.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. 1: 14-wave tube 2: Sub-waveguide 3: Branch waveguide 4: (i'I band pass filter 5 two-step conversion section 1＼＼ Agent Uchihara's patent attorney)

Claims (1)

[Claims] a rectangular main waveguide that propagates electromagnetic waves of the same polarization in multiple frequency bands; a branch waveguide that is connected to one side of the main waveguide and includes a bandpass filter that passes only electromagnetic waves in a low frequency band; a sub-waveguide connected in series to the main waveguide and having a shape that provides a cut-off for electromagnetic waves in a low frequency band; and a branch waveguide at a joint between the main waveguide and the sub-waveguide. 1. A duplexer comprising a step conversion section provided on opposite surfaces for matching electromagnetic waves in a low frequency band and electromagnetic waves in a high frequency band.