CA1150372A - System filter for separating two signals - Google Patents
System filter for separating two signalsInfo
- Publication number
- CA1150372A CA1150372A CA000361225A CA361225A CA1150372A CA 1150372 A CA1150372 A CA 1150372A CA 000361225 A CA000361225 A CA 000361225A CA 361225 A CA361225 A CA 361225A CA 1150372 A CA1150372 A CA 1150372A
- Authority
- CA
- Canada
- Prior art keywords
- waveguide section
- frequency band
- filter
- signals
- waveguide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
- H01P1/161—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion sustaining two independent orthogonal modes, e.g. orthomode transducer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/213—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies
- H01P1/2131—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies with combining or separating polarisations
Landscapes
- Waveguide Switches, Polarizers, And Phase Shifters (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Waveguide Connection Structure (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A system filter for separating two signals consisting of first and second double linearly polarized frequency bands of different frequencies. The filter is of the type which includes first, second and third doubly polarizable series coupled wave-guide sections with the first waveguide section being dimensioned such that both frequency bands can exist therein with their double polarizations, and with the second and third waveguide sections being constructed such that the first frequency band forms standing waves in the second waveguide section and only the second frequency band exists in the third waveguide section, a coupling arrangement for coupling out the respective polari-zations of the signals in the first frequency band from the second waveguide section, hybrid circuits responsive to the out-put signals from the coupling arrangement for individually providing the signals of the two polarizations of the first frequency band at respective separate outputs, and a polarization filter connected to the third waveguide section and having separate outputs at which the signals of the two polarizations of the second frequency band are separately respectively available.
The entire system filter is mounted to be rotatable about its axis with respect to an antenna, and additionally, the polari-zation filter for the second frequency band is mounted to be axially rotatable with respect to the second waveguide section.
A system filter for separating two signals consisting of first and second double linearly polarized frequency bands of different frequencies. The filter is of the type which includes first, second and third doubly polarizable series coupled wave-guide sections with the first waveguide section being dimensioned such that both frequency bands can exist therein with their double polarizations, and with the second and third waveguide sections being constructed such that the first frequency band forms standing waves in the second waveguide section and only the second frequency band exists in the third waveguide section, a coupling arrangement for coupling out the respective polari-zations of the signals in the first frequency band from the second waveguide section, hybrid circuits responsive to the out-put signals from the coupling arrangement for individually providing the signals of the two polarizations of the first frequency band at respective separate outputs, and a polarization filter connected to the third waveguide section and having separate outputs at which the signals of the two polarizations of the second frequency band are separately respectively available.
The entire system filter is mounted to be rotatable about its axis with respect to an antenna, and additionally, the polari-zation filter for the second frequency band is mounted to be axially rotatable with respect to the second waveguide section.
Description
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~5`~372 BACKGROUND OF THE INVENTION
_ The present invention relates to a system filter for separating two signals each comprising two doubly linearly polarized frequency bands of different frequencies. More par-ticularly, the present invention relates to such a filter which includes first waveguide section in which both frequency bands exist with their double polarizations; a second waveguide section dimensioned in such a way that the first frequency band forms standing waves, and with this section being provided with coupling means for ~ach polarization which are arranged opposite one another in the walls and which are connected with associated lines and selection means having a pass band for the first fre-quency band, the electrically effective reflection plane of these lines and selection means producing total reflection for the second frequency band,and being interconnected via hybrid circuits in such a manner that the signals of both polarizations .
of the first frequency band are individually available at separate outputs; and a third waveguide section in which only ~- the second frequency band exists and to which there is connected ; 20 a polarization filter at whose outputs there appear the signals of the two polarizations of the second frequency band.
:, A system filter of this type is disclosed in U.S. Patent No. 3,978,434 issued August 31st, 1976 to Gunther Morz et al.
, The system filter disclosed in this patent is able to separate two doubly linearly polarized frequency bands with respect to ,~ their frequency bands and polarization directions. Each fre-quency band includes two signals whose field vectors are polarized
~5`~372 BACKGROUND OF THE INVENTION
_ The present invention relates to a system filter for separating two signals each comprising two doubly linearly polarized frequency bands of different frequencies. More par-ticularly, the present invention relates to such a filter which includes first waveguide section in which both frequency bands exist with their double polarizations; a second waveguide section dimensioned in such a way that the first frequency band forms standing waves, and with this section being provided with coupling means for ~ach polarization which are arranged opposite one another in the walls and which are connected with associated lines and selection means having a pass band for the first fre-quency band, the electrically effective reflection plane of these lines and selection means producing total reflection for the second frequency band,and being interconnected via hybrid circuits in such a manner that the signals of both polarizations .
of the first frequency band are individually available at separate outputs; and a third waveguide section in which only ~- the second frequency band exists and to which there is connected ; 20 a polarization filter at whose outputs there appear the signals of the two polarizations of the second frequency band.
:, A system filter of this type is disclosed in U.S. Patent No. 3,978,434 issued August 31st, 1976 to Gunther Morz et al.
, The system filter disclosed in this patent is able to separate two doubly linearly polarized frequency bands with respect to ,~ their frequency bands and polarization directions. Each fre-quency band includes two signals whose field vectors are polarized
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~5~372 orthogonally to one another. One signal of the one frequency band constitutes the received signal and the orthogonally polarized slgnal with respect thereto in the other frequency band constitutes the transmitting signal.
In satellite communication, the time variable, nonrecipro-cal mutual rotation of the receiving and transmitting vectors due to the Faraday effect has a negative effect on signal de-coupling in a frequency range below 10 GHz. The angles of rotation of the receiving vector and of the transmitting vector depend on the frequency and are different since receiving and transmitting vectors belong to different frequency bands. That means that even if there possibly occurs a reciprocal rotation of receiving and transmittingvectors, the latter are not perpen-,.
dicular to one another. In order to avoid signal coupling,care must be taken that the receiving vector and the transmitting vector are orthogonally polarized at the location of the satellite antenna and at the location of the ground station antenna and that the polarization of the vectors is oriented parallel to the polarization of the respective antenna.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to modify a system filter às disclosed in U.S. Patent No. 3,978,434 in a simple ; manner so that the rotations of the transmitting and receiving vectors as a result of the Faraday effect can be corrected in a simple manner.
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; - 3 -' ~5~372 The above object is achieved according to the present invention in that in a system filter for separating two signals consisting of first and second double linearly polarized fre-quency bands of different frequencies with thé filter being of the type including first, second and third doubly polarizable series coupled waveguide sections with the first waveguide section being dimensioned such that both frequency bands can exist therein with their double polarizations, and with the second and third waveguide sections being constructed such that the first frequency band forms standing waves in the second waveguide section and only the second frequency band exists in said third waveguide section, first and second coupl-ing means, each associated with a separate one of the two directions of polarization, for coupling out the respective polarizations of the signals in the first frequency band from the second waveguide section, hybrid circuit means responsive to the output signals from the coupling means ~or individually providing the signals of the two polarizations of the first frequency band at respective separate outputs, and a polarization filter connected to the third waveguide section and having sepa-rate outputs at which the signals of the two polarizations of ....
. the second frequency band are separately respectiv.ely available;
first means are provided for mounting the system filter on an antenna such that the entire system filter is rotatable about its axis with respect to the antenna, and second means are pro-, vided for mounting the polarization filter so that it is axially '~ rotatable with respect to the second waveguide section.
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~ l ' According to a preferred embodiment the first means compri-ses a waveguide section, including a rotatable coupling, which is arranged at the antenna side output of the first waveguide section and the second means comprises a rotatable coupling included in the third waveguide section which is disposed between the second waveguide section and the polarization filter for the second frequenc~ band.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side view of the system filter with rotatable 10 couplings according to the invention.
-~ Figure 2 is a top view (in the direction of the arrow x) of the system filter according to the invention shown in Figure 1.
Figure 3 is a schematic cross-sectional view showing the interior of the waveguide section 2 of Figure 1 and the coupling arrangements as well as the circuits connected to the coupling elements in block circuit form.
Figure 4 is a perspective view of a rotatable waveguide coupling with transition pieces from circular to square wave-guide cross-sections.
; 20 Figure 5 is an enlarged partial longitudinal sectional view along the line A-A of Figure 4 and in the area of the joint of the rotatable waveguide coupling.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to Figures 1 and 2 there is shown a modified system filter based on the filter disclosed in the above mentioned U.S. Patent No. 3,978,434. The prior art system filter disclosed in this patent is composed of an initial doubly polarizable waveguide section 1, e.g. having a square cross-section, in which signals exist which originate from two different frequency bands and are each doubly linearly polarized. In a subsequent doubly polarizable waveguide section 2, the two polarizations of one of the frequency bands, for example, the lower frequency band, is coupled out by means of a special coupling arrangement. The remaining frequency band, e.g., the upper frequency band, is transmitted on into a subsequent doubly polarizable waveguide section 3, e.g., having a square cross-section which is terminated by a polarization filter 4 at whose ~ outputs 5 and 6 the signals of the remaining, e.g., upper, frequency band ; appear separated into their polarization directions. The signals corres-ponding to the respective polarizations of the first frequency band coupled out of the waveguide section 2 are brought together through re-spective pairs of waveguide arms 7, 7' and 8, 8' and respective hybrid circuits Hl and H2 so that at the outputs 9 and 10 of the hybrid circuits Hl and H2 respectively, the signals of the first, e.g., lower, frequency band are likewise separately available according to their polarization directions.
The specific manner in which the various signals are decoupled and/or separated is described in detail in the above ,~p , identified U.S. Patent No. 3,978,434. However, in general, in order to permit the transmission of only the second frequency band to the polarization filter 4 and the coupling out of the first frequency band from the waveguide section 2, the waveguide - sections 2 and 3 are constructed such that the first frequency band cannot propagate in the waveguide section 3 and forms ~ standing waves in the waveguide section 2. In the preferred - embodiment of the invention wherein the first frequency band is lower in frequency than the second frequency band, this is preferably achieved by providing the inner cross-section of the waveguide section 3 with reduced dimensions such that while the higher second frequency band can be propagated therein the lower first frequency cannot be propagated, and by dimensioning the inner cross-section of the waveguide section 2 so that it forms a smooth transition between the respective cross-sections of the waveguide sections 1 and 3. Moreover, an embodiment of a coupling arrangement for coupling out the first frequency band from the ; waveguide section 2 is shown schematically in Figure 3.
, As shown in Figure 3, the first, e.g., lower frequency band, ' 20 is decoupled by means of four doubly symetrically arranged coupling :~ elements Kl, K2, K3 and K4 disposed in the walls of the waveguide section 2, with two oppositely disposed coupling elements Kl and ~ . ~
:: K3, and K2 and K4 respectively being provided for each polarization Pl or P2 of the first frequency band. Each of the coupling elements ~: Kl, K~, K3 and K4 is connected to a respective transmission line Ll, L2, L3 and L4 to which is connected a frequency selective arrangement or filter Fl, F2, F3, F4 respectively, which passes the first, e.g., lower, frequency band and blocks the second .; .
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e.g., higher, frequency band in that the electrically effective reflection plane of the filters and associated transmission lines effects total reflection of the second frequency band. The outputs of the associated filter pairs Fl, F3 and F2, F4 are connected together over the same elec-trical length arms 7, 7' and 8, 8' respectively via respective 180 hybrid circuits Hl and H2 respectively at whose respective sum outputs 9 and 10 the energy of one polarization Pl or P2 is then available. If desired, compensating or correcting pins K01, K02, K03, K04 may be dis-posed as shown, in a diagonal arrangement in the corners of the waveguide s~ection 2, i.e., at an angle of 45 with respect to the waveguide walls, in order to provide matching of one of the two frequency bands independ-, . . .
ently of the other requency band, ; According to the present invention, the known system filter has r ~ ~
been modified to the extent that the two reference systems of the two fre-quency bands are no longer rigidly oriented with respect to one another in that each reference system is rotatable about its axis independently of the other. This makes it possible in a simple manner to correct a shift in polarization in the received signal and/or in the transmitted signal which occurred as a result of the Faraday effect. A shift in polarization of the received signal can be compensated by a rotation of the reference system for the first or lower frequency band. For this purpose, as shown in Figure 1, an additional waveguide section including a rotary joint 11 is , " ., ~
disposed ahead of the first waveguide section 1 at its antenna side output.
This rotary joint 11 mak~; it possible to rotate the entire system filter .~ with respect to the antenna (not shown).
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A shift in polarization of the transmitted signal is can-celled out by rotating the polarization filter 4 for the second or upper frequency band relative to the waveguide section 2. This is made possible by a further rotary joint 12 included in the waveguide section between the polarization filter 4 and the waveguide section 2. The rotary joint 12 may be a portion of the waveguide section 3 or, as shown in Figure 1, may be connected between waveguide section
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~5~372 orthogonally to one another. One signal of the one frequency band constitutes the received signal and the orthogonally polarized slgnal with respect thereto in the other frequency band constitutes the transmitting signal.
In satellite communication, the time variable, nonrecipro-cal mutual rotation of the receiving and transmitting vectors due to the Faraday effect has a negative effect on signal de-coupling in a frequency range below 10 GHz. The angles of rotation of the receiving vector and of the transmitting vector depend on the frequency and are different since receiving and transmitting vectors belong to different frequency bands. That means that even if there possibly occurs a reciprocal rotation of receiving and transmittingvectors, the latter are not perpen-,.
dicular to one another. In order to avoid signal coupling,care must be taken that the receiving vector and the transmitting vector are orthogonally polarized at the location of the satellite antenna and at the location of the ground station antenna and that the polarization of the vectors is oriented parallel to the polarization of the respective antenna.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to modify a system filter às disclosed in U.S. Patent No. 3,978,434 in a simple ; manner so that the rotations of the transmitting and receiving vectors as a result of the Faraday effect can be corrected in a simple manner.
,.
; - 3 -' ~5~372 The above object is achieved according to the present invention in that in a system filter for separating two signals consisting of first and second double linearly polarized fre-quency bands of different frequencies with thé filter being of the type including first, second and third doubly polarizable series coupled waveguide sections with the first waveguide section being dimensioned such that both frequency bands can exist therein with their double polarizations, and with the second and third waveguide sections being constructed such that the first frequency band forms standing waves in the second waveguide section and only the second frequency band exists in said third waveguide section, first and second coupl-ing means, each associated with a separate one of the two directions of polarization, for coupling out the respective polarizations of the signals in the first frequency band from the second waveguide section, hybrid circuit means responsive to the output signals from the coupling means ~or individually providing the signals of the two polarizations of the first frequency band at respective separate outputs, and a polarization filter connected to the third waveguide section and having sepa-rate outputs at which the signals of the two polarizations of ....
. the second frequency band are separately respectiv.ely available;
first means are provided for mounting the system filter on an antenna such that the entire system filter is rotatable about its axis with respect to the antenna, and second means are pro-, vided for mounting the polarization filter so that it is axially '~ rotatable with respect to the second waveguide section.
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~ l ' According to a preferred embodiment the first means compri-ses a waveguide section, including a rotatable coupling, which is arranged at the antenna side output of the first waveguide section and the second means comprises a rotatable coupling included in the third waveguide section which is disposed between the second waveguide section and the polarization filter for the second frequenc~ band.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side view of the system filter with rotatable 10 couplings according to the invention.
-~ Figure 2 is a top view (in the direction of the arrow x) of the system filter according to the invention shown in Figure 1.
Figure 3 is a schematic cross-sectional view showing the interior of the waveguide section 2 of Figure 1 and the coupling arrangements as well as the circuits connected to the coupling elements in block circuit form.
Figure 4 is a perspective view of a rotatable waveguide coupling with transition pieces from circular to square wave-guide cross-sections.
; 20 Figure 5 is an enlarged partial longitudinal sectional view along the line A-A of Figure 4 and in the area of the joint of the rotatable waveguide coupling.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to Figures 1 and 2 there is shown a modified system filter based on the filter disclosed in the above mentioned U.S. Patent No. 3,978,434. The prior art system filter disclosed in this patent is composed of an initial doubly polarizable waveguide section 1, e.g. having a square cross-section, in which signals exist which originate from two different frequency bands and are each doubly linearly polarized. In a subsequent doubly polarizable waveguide section 2, the two polarizations of one of the frequency bands, for example, the lower frequency band, is coupled out by means of a special coupling arrangement. The remaining frequency band, e.g., the upper frequency band, is transmitted on into a subsequent doubly polarizable waveguide section 3, e.g., having a square cross-section which is terminated by a polarization filter 4 at whose ~ outputs 5 and 6 the signals of the remaining, e.g., upper, frequency band ; appear separated into their polarization directions. The signals corres-ponding to the respective polarizations of the first frequency band coupled out of the waveguide section 2 are brought together through re-spective pairs of waveguide arms 7, 7' and 8, 8' and respective hybrid circuits Hl and H2 so that at the outputs 9 and 10 of the hybrid circuits Hl and H2 respectively, the signals of the first, e.g., lower, frequency band are likewise separately available according to their polarization directions.
The specific manner in which the various signals are decoupled and/or separated is described in detail in the above ,~p , identified U.S. Patent No. 3,978,434. However, in general, in order to permit the transmission of only the second frequency band to the polarization filter 4 and the coupling out of the first frequency band from the waveguide section 2, the waveguide - sections 2 and 3 are constructed such that the first frequency band cannot propagate in the waveguide section 3 and forms ~ standing waves in the waveguide section 2. In the preferred - embodiment of the invention wherein the first frequency band is lower in frequency than the second frequency band, this is preferably achieved by providing the inner cross-section of the waveguide section 3 with reduced dimensions such that while the higher second frequency band can be propagated therein the lower first frequency cannot be propagated, and by dimensioning the inner cross-section of the waveguide section 2 so that it forms a smooth transition between the respective cross-sections of the waveguide sections 1 and 3. Moreover, an embodiment of a coupling arrangement for coupling out the first frequency band from the ; waveguide section 2 is shown schematically in Figure 3.
, As shown in Figure 3, the first, e.g., lower frequency band, ' 20 is decoupled by means of four doubly symetrically arranged coupling :~ elements Kl, K2, K3 and K4 disposed in the walls of the waveguide section 2, with two oppositely disposed coupling elements Kl and ~ . ~
:: K3, and K2 and K4 respectively being provided for each polarization Pl or P2 of the first frequency band. Each of the coupling elements ~: Kl, K~, K3 and K4 is connected to a respective transmission line Ll, L2, L3 and L4 to which is connected a frequency selective arrangement or filter Fl, F2, F3, F4 respectively, which passes the first, e.g., lower, frequency band and blocks the second .; .
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e.g., higher, frequency band in that the electrically effective reflection plane of the filters and associated transmission lines effects total reflection of the second frequency band. The outputs of the associated filter pairs Fl, F3 and F2, F4 are connected together over the same elec-trical length arms 7, 7' and 8, 8' respectively via respective 180 hybrid circuits Hl and H2 respectively at whose respective sum outputs 9 and 10 the energy of one polarization Pl or P2 is then available. If desired, compensating or correcting pins K01, K02, K03, K04 may be dis-posed as shown, in a diagonal arrangement in the corners of the waveguide s~ection 2, i.e., at an angle of 45 with respect to the waveguide walls, in order to provide matching of one of the two frequency bands independ-, . . .
ently of the other requency band, ; According to the present invention, the known system filter has r ~ ~
been modified to the extent that the two reference systems of the two fre-quency bands are no longer rigidly oriented with respect to one another in that each reference system is rotatable about its axis independently of the other. This makes it possible in a simple manner to correct a shift in polarization in the received signal and/or in the transmitted signal which occurred as a result of the Faraday effect. A shift in polarization of the received signal can be compensated by a rotation of the reference system for the first or lower frequency band. For this purpose, as shown in Figure 1, an additional waveguide section including a rotary joint 11 is , " ., ~
disposed ahead of the first waveguide section 1 at its antenna side output.
This rotary joint 11 mak~; it possible to rotate the entire system filter .~ with respect to the antenna (not shown).
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A shift in polarization of the transmitted signal is can-celled out by rotating the polarization filter 4 for the second or upper frequency band relative to the waveguide section 2. This is made possible by a further rotary joint 12 included in the waveguide section between the polarization filter 4 and the waveguide section 2. The rotary joint 12 may be a portion of the waveguide section 3 or, as shown in Figure 1, may be connected between waveguide section
3 and the polarization filter 4.
Figures 4 and 5 show a rotatable waveguide which may be used for the rotary joint 11 or 12. As shown, the rotary joint includes two portions 13 and 14 with a circular cross-section which are coupled together by means of joint including roller bearings 15 ` and a choke 19 in portion 14 so that the portions 13 and 14 are with-out galvanic contact axially relatively rotatable. Also the choke 19 keepts RF-energy from the roller bearings 15. Each of the wave-i,~
, guide portions 13 and 14 is provided with a transition portion 16 or ~i~ 17 respectively for matching the circular cros-s-section of the por-.....
q tions 13, 14 to that of the square cross-sections of the ~ssociated . .
~ connected waveguide sections 1, 3 or 4 of the system filter. Flanges .. :, l 20 18 are provided at the respective ends of rotatable waveguide coup--~ ling for making such connections.
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If de~red, the rqt~ti~n ~f the reference sy~tems~for the receiving and transmitting signals may be automatic. In such case, the rotary joints 11 and 12 are then provided with motor drives '; which are actuated by polarization sensors.
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~ In order to have sufficient space to accommodate the ~, , ~;~ rotary joint 12 coaxially with waveguide section 3 and the polari-, zation filter 4, the waveguide arms 7, 7' and 8, 8' are bent outward-ly, as shown in Figure 2, away from the axis of the system filter.
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~5~372 The above described system filter, provided with devices to correct shifts in polarization of the linearly polarized receiving and transmitting signals as a result of the Faraday effect, is distinguished by a very compact design which is of great advantage when such a system filter is used in a small ground station antenna.
It is to be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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Figures 4 and 5 show a rotatable waveguide which may be used for the rotary joint 11 or 12. As shown, the rotary joint includes two portions 13 and 14 with a circular cross-section which are coupled together by means of joint including roller bearings 15 ` and a choke 19 in portion 14 so that the portions 13 and 14 are with-out galvanic contact axially relatively rotatable. Also the choke 19 keepts RF-energy from the roller bearings 15. Each of the wave-i,~
, guide portions 13 and 14 is provided with a transition portion 16 or ~i~ 17 respectively for matching the circular cros-s-section of the por-.....
q tions 13, 14 to that of the square cross-sections of the ~ssociated . .
~ connected waveguide sections 1, 3 or 4 of the system filter. Flanges .. :, l 20 18 are provided at the respective ends of rotatable waveguide coup--~ ling for making such connections.
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If de~red, the rqt~ti~n ~f the reference sy~tems~for the receiving and transmitting signals may be automatic. In such case, the rotary joints 11 and 12 are then provided with motor drives '; which are actuated by polarization sensors.
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~ In order to have sufficient space to accommodate the ~, , ~;~ rotary joint 12 coaxially with waveguide section 3 and the polari-, zation filter 4, the waveguide arms 7, 7' and 8, 8' are bent outward-ly, as shown in Figure 2, away from the axis of the system filter.
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~5~372 The above described system filter, provided with devices to correct shifts in polarization of the linearly polarized receiving and transmitting signals as a result of the Faraday effect, is distinguished by a very compact design which is of great advantage when such a system filter is used in a small ground station antenna.
It is to be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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Claims (5)
1. In a system filter for separating two signals consist-ing of first and second double linearly polarized frequency bands of different frenquencies, said filter comprising, in combination: first, second and third doubly polarizable series coupled waveguide sections with said first waveguide section being dimensioned such that both frequency bands can exist therein with their double polarizations, and with said second and third waveguide sections being constructed such that said first frequency band forms standing waves in said second waveguide section and only said second frequency band exists in said third waveguide section;
coupling means for coupling out the respective polari-zations of the signals in said first frequency band from said second waveguide section; hybrid circuit means responsive to the output signals from said coupling means for individually providing the signals of said two polarizations of said first frequency band at respective separate outputs; and a polarization filter connected to said third waveguide section and having separate outputs at which the signals of the two polarizations of said second frequency band are separately respectively available;
the improvement wherein said system filter further comprises:
first means for mounting said system filter on an antenna such that the entire said system filter is rotatable about its axis with respect to the antenna; and second means for mounting said polarization filter so that it is axially rotatable with respect to said second waveguide section.
coupling means for coupling out the respective polari-zations of the signals in said first frequency band from said second waveguide section; hybrid circuit means responsive to the output signals from said coupling means for individually providing the signals of said two polarizations of said first frequency band at respective separate outputs; and a polarization filter connected to said third waveguide section and having separate outputs at which the signals of the two polarizations of said second frequency band are separately respectively available;
the improvement wherein said system filter further comprises:
first means for mounting said system filter on an antenna such that the entire said system filter is rotatable about its axis with respect to the antenna; and second means for mounting said polarization filter so that it is axially rotatable with respect to said second waveguide section.
2. A system filter as defined in claim 1 wherein: said first means comprises a further waveguide section having a rotary joint connected ahead of said first waveguide section at its antenna side output; and said second means comprises a rotary joint formed in said third waveguide section disposed between said second waveguide section and said polarization filter for said second frequency band.
3. A system filter as defined in claim 2 wherein said second waveguide section and said polarization filter each have a square cross-section; and wherein said third waveguide section includes first and second portions with a circular cross-section joined together at their adjacent ends by means of a rotatable joint, and third and fourth portions, each forming a transition from a circular to a square cross-section, connected to the other ends of said first and second portions respectively.
4. A system filter as defined in claim 1, 2 or 3 wherein said coupling means includes first and second coupling arrangements each associated with a separate one of the two directions of polari-zation, and with each said first and second coupling arrangements including a pair of coupling elements disposed opposite one another in the walls of said second waveguide section, and a transmission line and a frequency selective filter means for passing said first frequ-ency band connected to each said coupling element such that the electri-cally effective reflection plane of said line and said filter means effects a total reflection of the signals of said second frequency band.
5. A system filter as defined in claim 1, 2 or 3 wherein said coupling means includes first and second coupling arrangements each associated with a separate one of the two directions of polarization, and with each said first and second coupling arrangements including a pair of coupling elements disposed opposite one another in the walls of said second waveguide secton, and a transmission line and a frequency selective filter means for passing said first frequency band connected to each said coupling element such that the electrically effective reflec-tion plane of said line and said filter means effects a total reflection of the signals of said second frequency band, and wherein said first frequency band is the lower of the two frequency bands; the cross-section of said third waveguide section is dimensioned such that said first frequ-ency band cannot propagate therein; and the cross-section of said second waveguide section is dimensioned such that it forms a transition between the cross-sectional dimensions of said first and third waveguide sections.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2939679A DE2939679C2 (en) | 1979-09-29 | 1979-09-29 | System switch for a satellite radio system |
| DEP2939679.0 | 1979-09-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150372A true CA1150372A (en) | 1983-07-19 |
Family
ID=6082334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000361225A Expired CA1150372A (en) | 1979-09-29 | 1980-09-29 | System filter for separating two signals |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5651101A (en) |
| CA (1) | CA1150372A (en) |
| DE (1) | DE2939679C2 (en) |
| FR (1) | FR2466876A1 (en) |
| GB (1) | GB2061018A (en) |
| IT (1) | IT1132832B (en) |
| SE (1) | SE8006675L (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4504805A (en) * | 1982-06-04 | 1985-03-12 | Andrew Corporation | Multi-port combiner for multi-frequency microwave signals |
| US4912436A (en) * | 1987-06-15 | 1990-03-27 | Gamma-F Corporation | Four port dual polarization frequency diplexer |
| DE102013011651A1 (en) * | 2013-07-11 | 2015-01-15 | ESA-microwave service GmbH | Antenna feed system in the microwave range for reflector antennas |
| SE545208C2 (en) * | 2021-01-29 | 2023-05-23 | Ovzon Sweden Ab | Dual-Band Radio Terminal and Filter Structure |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3265993A (en) * | 1964-02-13 | 1966-08-09 | Post Office | Integrated coupling unit for two independent waveguide channels |
| US3731235A (en) * | 1971-11-03 | 1973-05-01 | Gte Sylvania Inc | Dual polarized diplexer |
| US3838362A (en) * | 1973-06-29 | 1974-09-24 | Emerson Electric Co | Diplexing coupler for microwave system |
| DE2443166C3 (en) * | 1974-09-10 | 1985-05-30 | ANT Nachrichtentechnik GmbH, 7150 Backnang | System switch for separating two signals, each consisting of two double polarized frequency bands |
| US4162463A (en) * | 1977-12-23 | 1979-07-24 | Gte Sylvania Incorporated | Diplexer apparatus |
-
1979
- 1979-09-29 DE DE2939679A patent/DE2939679C2/en not_active Expired
-
1980
- 1980-09-02 JP JP12074080A patent/JPS5651101A/en active Granted
- 1980-09-12 IT IT24639/80A patent/IT1132832B/en active
- 1980-09-18 GB GB8030250A patent/GB2061018A/en not_active Withdrawn
- 1980-09-24 SE SE8006675A patent/SE8006675L/en unknown
- 1980-09-29 FR FR8020828A patent/FR2466876A1/en active Pending
- 1980-09-29 CA CA000361225A patent/CA1150372A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6349921B2 (en) | 1988-10-06 |
| DE2939679A1 (en) | 1981-04-02 |
| DE2939679C2 (en) | 1985-12-05 |
| JPS5651101A (en) | 1981-05-08 |
| IT1132832B (en) | 1986-07-09 |
| FR2466876A1 (en) | 1981-04-10 |
| SE8006675L (en) | 1981-03-30 |
| GB2061018A (en) | 1981-05-07 |
| IT8024639A0 (en) | 1980-09-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |