CA1057829A - Waveguide circulator having single gyromagnetic element - Google Patents
Waveguide circulator having single gyromagnetic elementInfo
- Publication number
- CA1057829A CA1057829A CA210,732A CA210732A CA1057829A CA 1057829 A CA1057829 A CA 1057829A CA 210732 A CA210732 A CA 210732A CA 1057829 A CA1057829 A CA 1057829A
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- waveguide
- gyromagnetic
- circulator
- pedestal
- gyromagnetic element
- Prior art date
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Abstract
WAVEGUIDE CIRCULATOR HAVING SINGLE
GYROMAGNETIC ELEMENT
ABSTRACT
A three-port waveguide circulator has three waveguide arms meeting at a common junction. A gyromagnetic element is centrally situated at the junction and is subjected to the influence of a magnetic field during operation of the circulator. An appreciable saving in gyromagnetic material is effected by making the gyromagnetic element approximately one quarter wavelength long along its axis in the ferrite medium at the center frequency of the band and mounting that element upon a pedestal that rises from a transformer plate. Both the transformer plate and the pedestal effect a narrowing in the height of the waveguide. One face of the gyromagnetic element is short circuited by the pedestal whereas the opposite face is open-circuited by a dielectric gap between it and the waveguide wall. To permit the thickness of the gap to be adjusted the pedestal or a portion of the waveguide wall directly opposite the gyromagnetic element can be made movable. To tune the in-phase mode without appreciably affecting the counter-rotating modes, a thin tuning post is provided that extends into the dielectric gap from the waveguide wall opposite the open-circuited face of the gyromagnetic element.
GYROMAGNETIC ELEMENT
ABSTRACT
A three-port waveguide circulator has three waveguide arms meeting at a common junction. A gyromagnetic element is centrally situated at the junction and is subjected to the influence of a magnetic field during operation of the circulator. An appreciable saving in gyromagnetic material is effected by making the gyromagnetic element approximately one quarter wavelength long along its axis in the ferrite medium at the center frequency of the band and mounting that element upon a pedestal that rises from a transformer plate. Both the transformer plate and the pedestal effect a narrowing in the height of the waveguide. One face of the gyromagnetic element is short circuited by the pedestal whereas the opposite face is open-circuited by a dielectric gap between it and the waveguide wall. To permit the thickness of the gap to be adjusted the pedestal or a portion of the waveguide wall directly opposite the gyromagnetic element can be made movable. To tune the in-phase mode without appreciably affecting the counter-rotating modes, a thin tuning post is provided that extends into the dielectric gap from the waveguide wall opposite the open-circuited face of the gyromagnetic element.
Description
This invention relates in yeneral to apparatus for non-reciprocal transmission of electromagnetic wave energy and more particul~rly, the invention pertains to broadband waveguide y-jlmction circulators.
DISCUSSION OE~ TEIE PRIOR ART
.~ , ' , ,, :
The conventional three port waveguide symmetrical waveguide circulator employs three waveguide arms that are arrangecl at angles of 120 with respect to one another and meet at a common junction. Centrally disposed at the junction are one or more gyromagnetic members which are situated to preserve the symmetry of the junction. The gyromagnetic members are subjected to the influence of a magnetic field in the operation of the circulator to cause the ' ;' , .
:
.~
.
: : . :. . : . : : ~ .
.
:. . . ~ : .: . . , :. ,.
device to be a non-reciprocal transmi-tter of electro-magne-tic wave energy propagating in the waveguide. To improve the operating characteristics of the symmetrical y-junctlon circulator, modifications in the si~e and shape of the gyromagnetic members and in the matching the impedance of those members to the remainder of the structure have been made. The improved circulators have, in general, preserved the symmetry of the junction and have required gyro-magnetic members of appreciable volume.
U.S. patent 3,104,361 granted to J.G. Leetmaa, et al, discloses a circulator having a triangular gyromagnetic member situated between a pair of triangular transformer plates. The gyromagnetic member is entirely with the junction and the apexes of the triangular transformer pla-tes extend into the waveguide arms to provide an impedance match for the gyromagnetic member. The arrangement preserves the symmetry of the junction while providing an impedance matching structure that is asserted to be less frequency sensitive than conventional impedance transformers.
U.S.Patent 36849~3 Aug 15 1972 granted to J.J. Cotter, et al, discloses a circulator employing a pair of triangular gyromagnetic members separated by an i~erposqd die~lectricmember.The gyromagnetic members are disposed between a -~
pair of transition elements that reduce the height of the waveguide in two steps to prbvide impedance matching. The Cotter, et al, circulator preserves the symmetry of the junction but its construction is somewhat more critical than the Leetmaa, et al, circulator because Cotter, et al, uses two gyromagnetic members that must be maintained in alignment to preserve the symmetry of the junction, whereas Leetmaa, et al, employs a single gyromagnetic member.
However, even in the Leetmaa, et al, device, the upper and lower transformer plates must be maintained in alignment as well as the dielectric supports ; between which the gyromagnetic member is sandwiched.
, .
SUMMARY OF THE INVENTION
The invention resides in an improved three-port waveguide circulator of simplified construction that requires but a single gyromagnetic element
DISCUSSION OE~ TEIE PRIOR ART
.~ , ' , ,, :
The conventional three port waveguide symmetrical waveguide circulator employs three waveguide arms that are arrangecl at angles of 120 with respect to one another and meet at a common junction. Centrally disposed at the junction are one or more gyromagnetic members which are situated to preserve the symmetry of the junction. The gyromagnetic members are subjected to the influence of a magnetic field in the operation of the circulator to cause the ' ;' , .
:
.~
.
: : . :. . : . : : ~ .
.
:. . . ~ : .: . . , :. ,.
device to be a non-reciprocal transmi-tter of electro-magne-tic wave energy propagating in the waveguide. To improve the operating characteristics of the symmetrical y-junctlon circulator, modifications in the si~e and shape of the gyromagnetic members and in the matching the impedance of those members to the remainder of the structure have been made. The improved circulators have, in general, preserved the symmetry of the junction and have required gyro-magnetic members of appreciable volume.
U.S. patent 3,104,361 granted to J.G. Leetmaa, et al, discloses a circulator having a triangular gyromagnetic member situated between a pair of triangular transformer plates. The gyromagnetic member is entirely with the junction and the apexes of the triangular transformer pla-tes extend into the waveguide arms to provide an impedance match for the gyromagnetic member. The arrangement preserves the symmetry of the junction while providing an impedance matching structure that is asserted to be less frequency sensitive than conventional impedance transformers.
U.S.Patent 36849~3 Aug 15 1972 granted to J.J. Cotter, et al, discloses a circulator employing a pair of triangular gyromagnetic members separated by an i~erposqd die~lectricmember.The gyromagnetic members are disposed between a -~
pair of transition elements that reduce the height of the waveguide in two steps to prbvide impedance matching. The Cotter, et al, circulator preserves the symmetry of the junction but its construction is somewhat more critical than the Leetmaa, et al, circulator because Cotter, et al, uses two gyromagnetic members that must be maintained in alignment to preserve the symmetry of the junction, whereas Leetmaa, et al, employs a single gyromagnetic member.
However, even in the Leetmaa, et al, device, the upper and lower transformer plates must be maintained in alignment as well as the dielectric supports ; between which the gyromagnetic member is sandwiched.
, .
SUMMARY OF THE INVENTION
The invention resides in an improved three-port waveguide circulator of simplified construction that requires but a single gyromagnetic element
(2) . . , ., . . , :
. ;. :., ,. . , . ~ . : -, , :. .
~a~7~
approximately one quarter wavelength long measured in the gyromagnetic material.
Only one transformer plate is required although two transformer pla-tes may be used. To minimize the cost of manufacture and avoid the necess:Lty for aligning two transEormer plates, a one transformer plate construction is preferred. The gyromagnetic member is disposed at the center of the junction with one face spaced frorn the waveguide wall by a diel~ctric gap which can be made adjustable to facilitate tuning of the device. The opposite face of the gyromagnetic member is disposed upon a conductive member so that that face is short~
circuited whereas the obverse face is open circuited at the dielectric gap.
Because of the asymmetrical arrangement of the gyromagnetic member, an additional advantage is gained in that the higher order modes are shifted to a portion of the frequency spectrum outside the band of intended operation of the circulator. The invention, because it employs a single quarter wave gyromagnetic element, permits a reduction in weight to be achieved over conventional circulators which employ three quarter wavelength or one half wavelength gyromagnetic elements. Moreover, an appreciable saving in cost can be realized by the reduction in volume of the ferrite or garnet gyromagnetic material needed for a quarter wavelength element, compared to the material neeaed for a half wave or three quarter wave length element.
THE DRAWI~GS
The invention, both as to its construction and its mode of operation, can be better understood from the detailed description that follows when it is considered in conjunction with the accompanying drawings in which:
Fig. 1 is a perspective view of a conventional prior art waveguide y-junction circulator in which interior components are depicted in phantom;
Fig. 2 is a cross-sectional view in elevation taken along the line 2-2 in Fig. l;
Fig. 3 is a perspective view of the preferred embodiment of the inventor in which parts are broken away to expose the interior of the circulator;
Fig. 4 is a cross-sectional view in elevation of the preferred embodiment of the invention taken along the line 4-4 in Fig. 3;
t3) s~ 3 Fig. 5 indicates dimensions to be considered in the construction oE
the preferred embodiment;
Fig. 6 depicts a modification of khe preferred embodiment which permits independent tuning of the in-phase mode by a central tuning post;
Fig. 7 depicts an embodiment of the invention employing a triangular gyromagnetic element and a triangular transformer plate.
DETAILED DESCRIPTION
Fig. 1 depicts a prior art waveguide y-junction circulator having three waveguide arms A, s and C meeting at a common junction. Centrally disposed at the junction are a pair of gyromagnetic disks 1 and 2, which for ;
ease of exposition are assumed to be of ferrite exhibiting gyromagnetic properties. The ferrite disks are identical in diameter and thickness and are separated by a gap that in some conventional circulators is filled with a dielectric material. The ferrite disks are disposed between a pair of circular transformer plates 3 and 4 that match the impedance of the ferrite disks to the waveguide structure. In the operation of the circulator, the ferrite disks are subjected to the influence of unidirectional magnetic field, represented in Fig. 1 by the arrow designated HDC. The magnetic field can be established by one or more permanent magnets or may be set up by an electromagnet having the ferrite disks between its pole pieces.
Electromagnetic wave energy entering waveguide arm A propagates to the ~nction and because of the gyromagnetic properties of the ferrite disks, substantially all the energy is directed into arm B. In the ideal waveguide `
.. : .
circulator, all the wave energy enters arm B and none enters arm C. The `~ ~ -`j circulator is not a reciprocal transmitter because wave energy entering arm B ~
is directed into arm C and not into arm A~ ~.
By changing the direction of ma~netic field HDC, the circulator can be operated as a switch in as much as a reversal in direction of that magnetic ~ -~
field causes electromagnetic wave energy entering arm A to be directed into arm C rather than into arm B.
" .
(4) ;. ~
Fig. 2 shows a cross-section of the prior art circulator taken along the plane 2-2 in Fig. 1. The ferrite disks 1, 2 must be maintained in alignment as well as the transformer plates 3, 4, to preserve the symmetry of the junction.
Construction of the circulator requires relatively precise dimensional control as there usually is no provision for adjustment of the gap between the ferrite disks after the device is assembled. Commonly, however, capacitive tuning screws, as shown in U.S. patent 3,593,210 July 13, 197_, granted to R.F. Skedd are-provided in each waveguide arm to faci7itate tuning.
Fig. 3 depicts the preferred embodiment of the invention with part of the waveguide top wall broken away to expose the interior of the circulator.
In the Fig. 3 arrangement the gyromagnetic element 5 is a disk of a mat~erial~
such as ferrite or garnet exhibiting gyromagnetic properties. The length of the disk along i~s axis is approximately a quarter wave length measured in the medium of the disk at a selected frequency in the operational band of the clrculator. The disk is mounted on a cylindrical boss 6 that rises from the transformer plate 7. As shown in the cross-sectional view of Fig. 4, a memher 8, threaded into the top wall of the`waveguide, is disposed directly over the gyromagnetic disk 5. The member 8, and boss 6, preferably are of the same diameter as the gyromagnetic disks. The member 8, essentially is an extension of the waveguide top wall which permits adjustment of the gap between that wall and the gyromagnetic disk. Because of that gap, the disk is open circuited at its upper face whereas the face that lies on the boss is short circuited.
Adjustment of the gap permits tuning of the circulator. To further facilitate tuning of the device, capacitive tuning screws 10, 11 and 12 are provided as indicated in Figs. 3 and 4. In each of the three waveguide arms, a capacitive tunlng screw is situated above the transformer plate.
The more lmportant dimensions to be dealt with in construction of an embodiment of the invention are indicated in Fig. 5. An embodiment of the invention of the general type shown in Figs. 3 and 4 was constructed using WR-90 waveguide arms and a gyromagnetic element constituted of TT390 ferrite.
The dimensions of that embodiment are as follows: a = .080", b = .060", (5) ., ,.' ~' :3~a~5 ~
c = .160", d = .395", and f = 1.130". The dimension indicated as h in Fig. 5 is .400" or WR-90 waveguide. rrhat embodiment operated with a VSWR (voltage standing wave ratio) of less -than 1.10 from 8.5 GHz to 9.6 GHz and was tuned with a capacitive screw in each arm located between the edge of the transformer plate and the ferrite disk and with the movable gap adjusting plate situated directly over the disk. Over a broader band extending from 8.0 G~z to 10.0 GHz, that embodiment operated with a VSWR of less than 1.30. To scale that embodiment for another frequency band, the Eoregoing dimensions, as a rough ;
calculation, can be multiplied by the factor ~ , where ~ is the center frequency of the new band. In addition, a ferrite material should be selected whose magnetization is close to the magnetization of rrT39o ferrite multiplied by the factor g o5 .
E'ig. 6 shows an embodiment of the invention that is an improvement upon the Fig. 4 circulator. In the Fig. 6 circulator the ferrite disk 12 is mounted on a boss 13 that can be moved to adjust the gap between the disk and the upper waveguide wall. rrhe boss is provided with threads that mate with threads on the transformer plate 14 whereby upon rotation of the boss, it moves ;
vertically as viewed in Fig. 6. Extending downwardly from the upper waveguide wall is a tuning post 15 situated over the center of the ferrite disk. The tuning post is threaded into the waveguiae wall to permit vertically movement of the post. Thetuning post is a thin, electrically conductive rod whose presence in the guide affects only the in-phase mode of the circulator. .
It has been established that circulator action depends upon the ; ;
relationship between the responses of the junction to three modes supported in the junction, viz., an in-phase mode and two counter-rotating modes, the reflection coefficients of which must be mutually displaced in phase by 120.
'rhe variations in bandwidth exhibited by different ~orms of circulators depend upon the dgree to which a particular structure maintains the requisite phase relation as frequency is changed and by the onset of higher order modes.
' (6) ~L~57~
The tuning post 15 permits -the in~phase mode -to be -tuned independently to cause i-ts rerlec-tlon coef'ficlent to be dls-placed by 120 with respect to -the o-ther modes. 'rhe in-phase mode has an electric fleld on the axls of symme-try such that the resonant frequency depends upon the pene-tratlon of the pos-t into the waveguide. The coun-ter-rotating modes have only transverse electric fields in the axis of symmetry and hence are not affected by the post if that post is slender.
The invention causes higher order modes to be shifted upward in frequency compared to the conventional prior art circulator and thereby provides an additional advantage. ;
Fig. 7. depicts an embodiment of the invention employing a triangular gyromagnetic element 16 mounted on a triangular boss 17rising from -the triangular transformer plate 18. A
tuning post 19, similar to the post of 15 in Fig. 6, is dis-posed directly over the center of gyromagnetic element. While not illustrated in the figure, capaci-tive tuning screws can ., :, .
be provided in each of the waveguide arms.
While not illustrated, a mixture of -triangular and cir-cular elements can be employed at the circulator's junc-tion.
For example, the transformer plate may be triangular and the , gyromagnetic element may be a disk disposed on a cylindrical boss.
, Although the invention has been illustrated as embodied in a symmetrical y-junction waveguide circulator, it can also take other forms such as a t-junction waveguide circulator.
In view of the different forms that the invention can take, it is not intended to limit the invention to the precise .. , ~ .
-' embodiments illustrated in the drawings. -,.
~ _7_ .. .. . . . . . .. .
. ;. :., ,. . , . ~ . : -, , :. .
~a~7~
approximately one quarter wavelength long measured in the gyromagnetic material.
Only one transformer plate is required although two transformer pla-tes may be used. To minimize the cost of manufacture and avoid the necess:Lty for aligning two transEormer plates, a one transformer plate construction is preferred. The gyromagnetic member is disposed at the center of the junction with one face spaced frorn the waveguide wall by a diel~ctric gap which can be made adjustable to facilitate tuning of the device. The opposite face of the gyromagnetic member is disposed upon a conductive member so that that face is short~
circuited whereas the obverse face is open circuited at the dielectric gap.
Because of the asymmetrical arrangement of the gyromagnetic member, an additional advantage is gained in that the higher order modes are shifted to a portion of the frequency spectrum outside the band of intended operation of the circulator. The invention, because it employs a single quarter wave gyromagnetic element, permits a reduction in weight to be achieved over conventional circulators which employ three quarter wavelength or one half wavelength gyromagnetic elements. Moreover, an appreciable saving in cost can be realized by the reduction in volume of the ferrite or garnet gyromagnetic material needed for a quarter wavelength element, compared to the material neeaed for a half wave or three quarter wave length element.
THE DRAWI~GS
The invention, both as to its construction and its mode of operation, can be better understood from the detailed description that follows when it is considered in conjunction with the accompanying drawings in which:
Fig. 1 is a perspective view of a conventional prior art waveguide y-junction circulator in which interior components are depicted in phantom;
Fig. 2 is a cross-sectional view in elevation taken along the line 2-2 in Fig. l;
Fig. 3 is a perspective view of the preferred embodiment of the inventor in which parts are broken away to expose the interior of the circulator;
Fig. 4 is a cross-sectional view in elevation of the preferred embodiment of the invention taken along the line 4-4 in Fig. 3;
t3) s~ 3 Fig. 5 indicates dimensions to be considered in the construction oE
the preferred embodiment;
Fig. 6 depicts a modification of khe preferred embodiment which permits independent tuning of the in-phase mode by a central tuning post;
Fig. 7 depicts an embodiment of the invention employing a triangular gyromagnetic element and a triangular transformer plate.
DETAILED DESCRIPTION
Fig. 1 depicts a prior art waveguide y-junction circulator having three waveguide arms A, s and C meeting at a common junction. Centrally disposed at the junction are a pair of gyromagnetic disks 1 and 2, which for ;
ease of exposition are assumed to be of ferrite exhibiting gyromagnetic properties. The ferrite disks are identical in diameter and thickness and are separated by a gap that in some conventional circulators is filled with a dielectric material. The ferrite disks are disposed between a pair of circular transformer plates 3 and 4 that match the impedance of the ferrite disks to the waveguide structure. In the operation of the circulator, the ferrite disks are subjected to the influence of unidirectional magnetic field, represented in Fig. 1 by the arrow designated HDC. The magnetic field can be established by one or more permanent magnets or may be set up by an electromagnet having the ferrite disks between its pole pieces.
Electromagnetic wave energy entering waveguide arm A propagates to the ~nction and because of the gyromagnetic properties of the ferrite disks, substantially all the energy is directed into arm B. In the ideal waveguide `
.. : .
circulator, all the wave energy enters arm B and none enters arm C. The `~ ~ -`j circulator is not a reciprocal transmitter because wave energy entering arm B ~
is directed into arm C and not into arm A~ ~.
By changing the direction of ma~netic field HDC, the circulator can be operated as a switch in as much as a reversal in direction of that magnetic ~ -~
field causes electromagnetic wave energy entering arm A to be directed into arm C rather than into arm B.
" .
(4) ;. ~
Fig. 2 shows a cross-section of the prior art circulator taken along the plane 2-2 in Fig. 1. The ferrite disks 1, 2 must be maintained in alignment as well as the transformer plates 3, 4, to preserve the symmetry of the junction.
Construction of the circulator requires relatively precise dimensional control as there usually is no provision for adjustment of the gap between the ferrite disks after the device is assembled. Commonly, however, capacitive tuning screws, as shown in U.S. patent 3,593,210 July 13, 197_, granted to R.F. Skedd are-provided in each waveguide arm to faci7itate tuning.
Fig. 3 depicts the preferred embodiment of the invention with part of the waveguide top wall broken away to expose the interior of the circulator.
In the Fig. 3 arrangement the gyromagnetic element 5 is a disk of a mat~erial~
such as ferrite or garnet exhibiting gyromagnetic properties. The length of the disk along i~s axis is approximately a quarter wave length measured in the medium of the disk at a selected frequency in the operational band of the clrculator. The disk is mounted on a cylindrical boss 6 that rises from the transformer plate 7. As shown in the cross-sectional view of Fig. 4, a memher 8, threaded into the top wall of the`waveguide, is disposed directly over the gyromagnetic disk 5. The member 8, and boss 6, preferably are of the same diameter as the gyromagnetic disks. The member 8, essentially is an extension of the waveguide top wall which permits adjustment of the gap between that wall and the gyromagnetic disk. Because of that gap, the disk is open circuited at its upper face whereas the face that lies on the boss is short circuited.
Adjustment of the gap permits tuning of the circulator. To further facilitate tuning of the device, capacitive tuning screws 10, 11 and 12 are provided as indicated in Figs. 3 and 4. In each of the three waveguide arms, a capacitive tunlng screw is situated above the transformer plate.
The more lmportant dimensions to be dealt with in construction of an embodiment of the invention are indicated in Fig. 5. An embodiment of the invention of the general type shown in Figs. 3 and 4 was constructed using WR-90 waveguide arms and a gyromagnetic element constituted of TT390 ferrite.
The dimensions of that embodiment are as follows: a = .080", b = .060", (5) ., ,.' ~' :3~a~5 ~
c = .160", d = .395", and f = 1.130". The dimension indicated as h in Fig. 5 is .400" or WR-90 waveguide. rrhat embodiment operated with a VSWR (voltage standing wave ratio) of less -than 1.10 from 8.5 GHz to 9.6 GHz and was tuned with a capacitive screw in each arm located between the edge of the transformer plate and the ferrite disk and with the movable gap adjusting plate situated directly over the disk. Over a broader band extending from 8.0 G~z to 10.0 GHz, that embodiment operated with a VSWR of less than 1.30. To scale that embodiment for another frequency band, the Eoregoing dimensions, as a rough ;
calculation, can be multiplied by the factor ~ , where ~ is the center frequency of the new band. In addition, a ferrite material should be selected whose magnetization is close to the magnetization of rrT39o ferrite multiplied by the factor g o5 .
E'ig. 6 shows an embodiment of the invention that is an improvement upon the Fig. 4 circulator. In the Fig. 6 circulator the ferrite disk 12 is mounted on a boss 13 that can be moved to adjust the gap between the disk and the upper waveguide wall. rrhe boss is provided with threads that mate with threads on the transformer plate 14 whereby upon rotation of the boss, it moves ;
vertically as viewed in Fig. 6. Extending downwardly from the upper waveguide wall is a tuning post 15 situated over the center of the ferrite disk. The tuning post is threaded into the waveguiae wall to permit vertically movement of the post. Thetuning post is a thin, electrically conductive rod whose presence in the guide affects only the in-phase mode of the circulator. .
It has been established that circulator action depends upon the ; ;
relationship between the responses of the junction to three modes supported in the junction, viz., an in-phase mode and two counter-rotating modes, the reflection coefficients of which must be mutually displaced in phase by 120.
'rhe variations in bandwidth exhibited by different ~orms of circulators depend upon the dgree to which a particular structure maintains the requisite phase relation as frequency is changed and by the onset of higher order modes.
' (6) ~L~57~
The tuning post 15 permits -the in~phase mode -to be -tuned independently to cause i-ts rerlec-tlon coef'ficlent to be dls-placed by 120 with respect to -the o-ther modes. 'rhe in-phase mode has an electric fleld on the axls of symme-try such that the resonant frequency depends upon the pene-tratlon of the pos-t into the waveguide. The coun-ter-rotating modes have only transverse electric fields in the axis of symmetry and hence are not affected by the post if that post is slender.
The invention causes higher order modes to be shifted upward in frequency compared to the conventional prior art circulator and thereby provides an additional advantage. ;
Fig. 7. depicts an embodiment of the invention employing a triangular gyromagnetic element 16 mounted on a triangular boss 17rising from -the triangular transformer plate 18. A
tuning post 19, similar to the post of 15 in Fig. 6, is dis-posed directly over the center of gyromagnetic element. While not illustrated in the figure, capaci-tive tuning screws can ., :, .
be provided in each of the waveguide arms.
While not illustrated, a mixture of -triangular and cir-cular elements can be employed at the circulator's junc-tion.
For example, the transformer plate may be triangular and the , gyromagnetic element may be a disk disposed on a cylindrical boss.
, Although the invention has been illustrated as embodied in a symmetrical y-junction waveguide circulator, it can also take other forms such as a t-junction waveguide circulator.
In view of the different forms that the invention can take, it is not intended to limit the invention to the precise .. , ~ .
-' embodiments illustrated in the drawings. -,.
~ _7_ .. .. . . . . . .. .
Claims (3)
1. In a three-port waveguide circulator of the type having:
(i) three waveguide arms meeting at a common junction and (ii) a gyromagnetic element centrally situated in the junction the improvement wherein (a) the gyromagnetic element is substantially one quarter wavelength long along its axis in the ferrite medium at a frequency within the operational band of the circulator.
(b) the gyromagnetic element is mounted on an electrically conductive pedestal, (c) one face of the gyromagnetic element is short circuited by the pedestal and the opposite face of the gyromagnetic element is spaced from the waveguide wall by a dielectric gap and (d) the pedestal is supported upon an impedance transformer plate.
(i) three waveguide arms meeting at a common junction and (ii) a gyromagnetic element centrally situated in the junction the improvement wherein (a) the gyromagnetic element is substantially one quarter wavelength long along its axis in the ferrite medium at a frequency within the operational band of the circulator.
(b) the gyromagnetic element is mounted on an electrically conductive pedestal, (c) one face of the gyromagnetic element is short circuited by the pedestal and the opposite face of the gyromagnetic element is spaced from the waveguide wall by a dielectric gap and (d) the pedestal is supported upon an impedance transformer plate.
2. The improved three-part waveguide circulator according to claim 1, wherein (e) the gyromagnetic element is a circular disk, (f) the pedestal is a cylinder of the same diameter as the circular disk, and (g) a circular plate is disposed directly over the gyromagnetic disk and is movably mounted in the waveguide wall for adjustment of the dielectric gap.
3. The improved three-port waveguide circulator according to claim 1, wherein the improvement further includes (h) an electrically conductive slender post extending from one wall of the waveguide into the dielectric gap, the post affecting the in-phase without appreciably affecting the counter-rotating modes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA210,732A CA1057829A (en) | 1974-10-03 | 1974-10-03 | Waveguide circulator having single gyromagnetic element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA210,732A CA1057829A (en) | 1974-10-03 | 1974-10-03 | Waveguide circulator having single gyromagnetic element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1057829A true CA1057829A (en) | 1979-07-03 |
Family
ID=4101288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA210,732A Expired CA1057829A (en) | 1974-10-03 | 1974-10-03 | Waveguide circulator having single gyromagnetic element |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1057829A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106207348A (en) * | 2016-08-30 | 2016-12-07 | 江苏贝孚德通讯科技股份有限公司 | A kind of waveguide junction circulator |
-
1974
- 1974-10-03 CA CA210,732A patent/CA1057829A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106207348A (en) * | 2016-08-30 | 2016-12-07 | 江苏贝孚德通讯科技股份有限公司 | A kind of waveguide junction circulator |
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