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Title: Microwave bank branching arrangements
Claims: I claim: 1. A microwave band branching arrangement including the sequential connection of a bifurcation for transferring TE.sub.01 mode energy at one end thereof from a circularly sectioned waveguide to TE.sub.01 mode energy in two semi-circularly sectioned waveguides at the other end thereof, the TE.sub.01 mode energy in each of the semi-circular waveguides being in phase opposition, a first centre excited coupler for transferring the TE.sub.01 mode energy above a first predetermined frequency from the said two semi-circularly sectioned waveguides to a TE.sub.10 mode in an axially, centrally disposed waveguide having a rectangular cross-section with the narrow walls thereof connected to the flat sides of the semi-circular waveguides, a phase shifter and a low pass filter for permitting energy below said first predetermined frequency to pass therethrough with a phase shift governed by the phase shifter and arranged to reflect TE.sub.01 mode energy above said predetermined frequency such that the TE.sub.01 mode energy above said predetermined frequency is reflected with an in-phase relationship so that it is capable of being coupled by the said rectangularly sectioned waveguide, a further phase shifter for restoring the phase opposition relationship between the TE.sub.01 mode energy below said predetermined frequency, a second centre excited coupler for transferring TE.sub.01 mode energy below a second predetermined frequency from two semi-circularly sectioned waveguides to a TE.sub.10 mode energy in an axially, centrally disposed waveguide having a rectangular cross-section with the narrow walls thereof connected to the flat sides of the semi-circularly sectioned waveguides, said second predetermined frequency being below said first predetermined frequency, a reflection filter for permitting energy above said second predetermined frequency to pass substantially unaffected therethrough and for reflecting energy below said second predetermined frequency so as to provide an in-phase relationship between the TE.sub.01 mode energy reflected thereby the energy then being capable of being coupled by the rectangularly sectioned waveguide of said second centre excited coupler, a third centre excited coupler for transferring TE.sub.01 mode energy below a third predetermined frequency from two semi-circularly sectioned waveguides to TE.sub.10 mode energy in an axially, centrally, disposed waveguide having a rectangular cross-section with the narrow walls thereof connected to the flat sides of the semi-circularly sectioned waveguides, said third predetermined frequency being above said second predetermined frequency but below said first predetermined frequency, a further reflection filter for permitting energy above said third predetermined frequency to pass substantially unaffected therethrough and for reflecting energy below said third predetermined frequency so as to provide an in-phase relationship between TE.sub.01 mode energy reflected thereby, the energy then being capable of being coupled by the rectangular waveguide of said third centre excited coupler, and a fourth centre excited coupler for transferring TE.sub.01 mode energy above said third predetermined frequency but below said first predetermined frequency from two semi-circulary sectioned waveguides to TE.sub.10 mode energy in an axially, centrally disposed waveguide having a rectangular cross-section with the broad walls thereof connected to the flat sides of the semi-circular waveguides. 2. A microwave band branching arrangement for use in a repeater station including the sequential connection of a bifurcation for transferring TE.sub.01 mode energy at one end thereof from a circularly sectioned waveguide to a TE.sub.01 mode into two semi-circularly sectioned waveguides at the other end thereof, a first centre excited coupler for coupling energy above a first predetermined frequency, a first phase shifter and low pass filter for permitting energy below said first predetermined frequency to pass therethrough with a phase shift governed by the phase shifter and arranged to reflect energy above said first predetermined frequency so that the TE.sub.01 mode energy above said first predetermined frequency is reflected with an in-phase relationship for it to be coupled by the rectangularly sectioned waveguide of said first centre excited coupler, a further phase shifter for restoring the phase opposition relationship between the TE.sub.01 mode energy below said first predetermined frequency, a second centre excited coupler for coupling frequencies below a second predetermined frequency which is below said first predetermined frequency, a reflection filter for permitting TE.sub.01 energy above said second predetermined frequency to pass substantially unaffected therethrough and for reflecting energy below said second predetermined frequency so as to provide an in-phase relationship between the TE.sub.01 mode energy reflected thereby for it to be coupled by the rectangularly sectioned waveguide of said second centre excited coupler, a third centre excited coupler also for coupling frequencies below said second predetermined frequency, a second phase shifter and low pass filter for permitting energy below said first predetermined frequency to pass therethrough with a phase shift governed by the phase shifter and arranged to reflect energy above said first predetermined frequency such that the TE.sub.01 mode energy above said first predetermined frequency is reflected with an in-phase relationship for it to be coupled by the rectangularly sectioned waveguide of a fourth centre excited coupler. 3. A microwave band branching arrangement as claimed in claim 2 wherein isolation means with regard to the TE.sub.01 mode energy below said second predetermined frequency in addition to said reflection filter are provided between said second and third centre excited couplers. 4. A microwave band branching arrangement as claimed in claim 3 wherein said isolation means comprise two further centre excited couplers each for coupling energy below said first predetermined frequency and above said second predetermined frequency with a high pass filter for passing TE.sub.10 mode energy above said second predetermined frequency connected between the rectangularly sectioned waveguides of the two further centre excited couplers, one of the two further centre excited couplers being connected to the reflection filter and the other of said two further centre excited couplers being connected to the third centre excited coupler through the intermediary of a further reflection filter also arranged to permit TE.sub.01 energy above said second predetermined frequency to pass substantially unaffected therethrough. 5. A microwave band branching arrangement for successively coupling out frequency sub-bands germane to a broad frequency band, comprising bifurcation means for dividing applied microwave energy into two parallel paths and a series of successive center excited coupler means for sequentially coupling out different frequency sub-bands of said energy, each coupler means comprising two outer waveguide sections, each forming part of one of said two parallel paths, and an inner waveguide section coupled with said outer waveguide sections and being provided for taking off the energy of a respective frequency sub-band, that one coupler means which is provided for coupling out the highest frequency sub-band being disposed directly behind said bifurcation means and ahead of the remaining coupler means, one of said parallel paths including a reflection low pass filter connected to one outer waveguide of said one coupler means and a 90.degree. phase shifter connected to such filter, and the other parallel path including a second 90.degree. phase shifter connected to the other outer waveguide section of said one coupler means and a second reflection low pass filter connected to said second phase shifter. 6. A microwave branching arrangement as defined in claim 5 wherein said outer waveguide sections are semi-circularly sectioned waveguides and said inner waveguide section is of rectangular cross-section with the narrow walls thereof connected to the flat sides of the semi-circularly sectioned waveguides. 7. A microwave branching arrangement comprising, in combination: bifurcation means, having an input port receiving a broad frequency band of microwave energy and a pair of output ports, for dividing the energy received into two parallel paths in which the energy is in phase opposition; coupler means connected to said output ports for coupling out a sub-band of frequencies within said broad band, which sub-band is the highest frequency band in said broad band, said coupling means comprising a center excited coupler having two outer waveguide sections respectively forming portions of said two paths and an inner waveguide section coupled to said outer waveguide sections for coupling out said sub-band when the frequencies in said two paths are in phase; and phase shifting and reflecting means for causing said outer waveguide sections to receive reflected energy which is in phase such that said sub-band is coupled out of said coupler means, said phase shifting and reflecting means comprising low pass filter means downstream of said coupler means in both of said paths for passing microwave energy below that frequency at the lower end of said sub-band and reflecting the energy in said sub-band back to said coupler means, and a 90.degree. phase shifter in one of said paths between said coupler means and said filter means whereby said energy which is reflected in said paths reaches said coupler means in phase. 8. A microwave branching arrangement as defined in claim 7 including a further 90.degree. phase shifter disposed in said other path downstream of said filter means for restoring said out of phase relation between the two paths. Other info: Inventors: Watson, Barry K. (Witham, GB) Application Number: 757558 Filing Date: 1977-01-07 Publication_date: 1978-08-29 Assignee: The Marconi Company Limited (Chelmsford, GB) Primary Class(es): 333/110 333/1, 333/17.1, 333/137 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Gensler, Paul L. Assistant Examiner: Attorney: Diller, Brown, Ramik & Wight |
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