CA2054996A1 - In-line folded microwave filter - Google Patents
In-line folded microwave filterInfo
- Publication number
- CA2054996A1 CA2054996A1 CA 2054996 CA2054996A CA2054996A1 CA 2054996 A1 CA2054996 A1 CA 2054996A1 CA 2054996 CA2054996 CA 2054996 CA 2054996 A CA2054996 A CA 2054996A CA 2054996 A1 CA2054996 A1 CA 2054996A1
- Authority
- CA
- Canada
- Prior art keywords
- series
- filter
- sub
- cavity
- cavities
- 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.)
- Abandoned
Links
Landscapes
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
Abstract An in-line folded microwave filter comprises a plurality of resonant cavities connected in a series between an input and an output at opposite ends of the filter. The resonant cavities are arranged in two parallel sub-series with the signal path proceeding from the input to a first cavity in one sub-series, then to a first cavity in the second sub-series, then to a second cavity in the second sub-series, then to a second cavity in the first sub-series, and so on through the cavities up to the output.
Description
.
IN-LINE FOLDED MICROWAVE FILq!ER
This invention relates to a microwave filter for filtering input signals to within a predetermined frequency band.
One type of microwave filter comprises a plurality of 5 resonant cavities coupled together in a series. Typically the series of resonant cavities are arranged in a straight line between an input and an output of the filter.
In some circumstances there is a limited space in which to install a microwave filter, in particular only a short space 10 may be available between the end of an input waveguide and the end of an output waveguide, between which the filter is to be fitted.
In accordance with this invention, there is provided a filter comprising a plurality of resonant cavities coupled 15 together in a series between an input and an output at opposite ends of the filter, the cavities being arranged in two parallel sub-series with the signal path proceeding from the input to a first cavity in one sub-series, then to a first cavity in the second sub-series, then to a second cavity in the second sub-20 series, then to a second cavity in the first sub-series, and so on up to the output.
Typically therefore, the filter may comprise 2n resonant cavities coupled in a series but have half the length of a normal filter of the same number of cavities.
Preferably the input and output of the filter face in opposite directions, so that the filter receives the input signal in one direction and the output signal continues travelling in the same direction.
Preferably the two sub-series of resonant cavities are separated by a common partition wall. Adjacent cavities in each sub-series are also separated by partition walls.
Coupling between adjacent cavities in the same sub-series is effected by means of an aperture or iris in the respective partition wall: preferably this iris is offset towards one 35 side of the filter. Coupling between a cavity of one sub-series and a cavity of the other sub-series is effected by means of an aperture or iris in the common partition wall between these cavities: this iris is offset towards the . . , - :. :. . , ~,. . : . .
,, . . . . ~ . . . .~ ...................................... .
: . ~ . . . : . .
20~996 opposite side of the filter; further this iris is adjacent one of the sub-series partition walls. These arrangements avoid or minimise coupling between non-consecutive cavities of the overall series.
An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which:
FIGURE 1 is a plan view of a microwave filter in accordance with the invention, shown with its top closure plate 10 or lid removed;
FIGURE 2 is a side view of the filter;
FIGURE 3 is a view of one end of the filter; and FIGURE 4 is a view of the opposite end of the filter.
Referring to the drawings, there is shown a microwave filter body 10 formed in one-piece and comprising two parallel side walls 11, 12 connected along their centre lines by a partition wall 13. on one side of the partition wall 13 there are three rectangular resonant cavities 23, 24, 25 and on the other side of the partition wall 13 there are three rectangular 20 resonant cavities 26, 27, 28. The six cavities 23 to 28 are coupled in a series between rectangular input and output apertures 14, 15 in end walls 16, 17 of the filter, as will be described below, with cavities 23 to 25 forming one sub-series and cavities 26 to 28 forming a second sub-series. Adjacent 25 cavities in each sub-series are separated by partition walls 41 to 43. The sub-series of cavities 26 to 28 are open to the top of the body 10 but are closed by a top closure plate or lid 50 fitted to the body 10: similarly the second sub-series of cavities are closed by a bottom plate 52 fitted to the body 10.
Cavity 23 is coupled to cavity 26 by an elongate slot or iris 30 in the common partition wall 13 adjacent the end wall 16. Cavity 26 is coupled to cavity 27 by a rectangular aperture or iris 31 in the wall 42 between these cavities.
Cavity 27 is coupled to cavity 24 by a slot 32 in common 35 partition wall 13, adjacent partition wall 42. Cavity 24 is coupled to cavity 25 by a rectangular aperture, similar to aperture 31, in the partition wall 41 between those cavities.
Cavity 25 is coupled to cavity 2~ by a slot 33 in common partition wall 13, adjacent partition wall 43. Cavity 28 is , 20~4996 coupled to the output through aperture 15 in the end wall 17.
It will be noted that the slots 30, 32, 33 are offset towards side wall 11 of the filter, whilst the apertures e.g.
31 in the partition walls 42, 41 are offset towards the 5 opposite side wall 12. These arrangements, together with the positioning of the slots 30, 32, 33 adjacent the partition walls 16, 42, 43, avoid direct coupling between non-consecutive cavities in the series 23, 26, 24, 27, 25, 28.
In use, the opposite ends of the filter are coupled to input and output lengths of rectangular-section waveguide. The resonant cavities support TEol mode wave patterns.
. .....
~ .
. : ' : . - - . , . :.. -.. .. , :~ .. , - . .
' ' . . ' ''' . '.' '' "' " ' ' ' ' ' .
IN-LINE FOLDED MICROWAVE FILq!ER
This invention relates to a microwave filter for filtering input signals to within a predetermined frequency band.
One type of microwave filter comprises a plurality of 5 resonant cavities coupled together in a series. Typically the series of resonant cavities are arranged in a straight line between an input and an output of the filter.
In some circumstances there is a limited space in which to install a microwave filter, in particular only a short space 10 may be available between the end of an input waveguide and the end of an output waveguide, between which the filter is to be fitted.
In accordance with this invention, there is provided a filter comprising a plurality of resonant cavities coupled 15 together in a series between an input and an output at opposite ends of the filter, the cavities being arranged in two parallel sub-series with the signal path proceeding from the input to a first cavity in one sub-series, then to a first cavity in the second sub-series, then to a second cavity in the second sub-20 series, then to a second cavity in the first sub-series, and so on up to the output.
Typically therefore, the filter may comprise 2n resonant cavities coupled in a series but have half the length of a normal filter of the same number of cavities.
Preferably the input and output of the filter face in opposite directions, so that the filter receives the input signal in one direction and the output signal continues travelling in the same direction.
Preferably the two sub-series of resonant cavities are separated by a common partition wall. Adjacent cavities in each sub-series are also separated by partition walls.
Coupling between adjacent cavities in the same sub-series is effected by means of an aperture or iris in the respective partition wall: preferably this iris is offset towards one 35 side of the filter. Coupling between a cavity of one sub-series and a cavity of the other sub-series is effected by means of an aperture or iris in the common partition wall between these cavities: this iris is offset towards the . . , - :. :. . , ~,. . : . .
,, . . . . ~ . . . .~ ...................................... .
: . ~ . . . : . .
20~996 opposite side of the filter; further this iris is adjacent one of the sub-series partition walls. These arrangements avoid or minimise coupling between non-consecutive cavities of the overall series.
An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which:
FIGURE 1 is a plan view of a microwave filter in accordance with the invention, shown with its top closure plate 10 or lid removed;
FIGURE 2 is a side view of the filter;
FIGURE 3 is a view of one end of the filter; and FIGURE 4 is a view of the opposite end of the filter.
Referring to the drawings, there is shown a microwave filter body 10 formed in one-piece and comprising two parallel side walls 11, 12 connected along their centre lines by a partition wall 13. on one side of the partition wall 13 there are three rectangular resonant cavities 23, 24, 25 and on the other side of the partition wall 13 there are three rectangular 20 resonant cavities 26, 27, 28. The six cavities 23 to 28 are coupled in a series between rectangular input and output apertures 14, 15 in end walls 16, 17 of the filter, as will be described below, with cavities 23 to 25 forming one sub-series and cavities 26 to 28 forming a second sub-series. Adjacent 25 cavities in each sub-series are separated by partition walls 41 to 43. The sub-series of cavities 26 to 28 are open to the top of the body 10 but are closed by a top closure plate or lid 50 fitted to the body 10: similarly the second sub-series of cavities are closed by a bottom plate 52 fitted to the body 10.
Cavity 23 is coupled to cavity 26 by an elongate slot or iris 30 in the common partition wall 13 adjacent the end wall 16. Cavity 26 is coupled to cavity 27 by a rectangular aperture or iris 31 in the wall 42 between these cavities.
Cavity 27 is coupled to cavity 24 by a slot 32 in common 35 partition wall 13, adjacent partition wall 42. Cavity 24 is coupled to cavity 25 by a rectangular aperture, similar to aperture 31, in the partition wall 41 between those cavities.
Cavity 25 is coupled to cavity 2~ by a slot 33 in common partition wall 13, adjacent partition wall 43. Cavity 28 is , 20~4996 coupled to the output through aperture 15 in the end wall 17.
It will be noted that the slots 30, 32, 33 are offset towards side wall 11 of the filter, whilst the apertures e.g.
31 in the partition walls 42, 41 are offset towards the 5 opposite side wall 12. These arrangements, together with the positioning of the slots 30, 32, 33 adjacent the partition walls 16, 42, 43, avoid direct coupling between non-consecutive cavities in the series 23, 26, 24, 27, 25, 28.
In use, the opposite ends of the filter are coupled to input and output lengths of rectangular-section waveguide. The resonant cavities support TEol mode wave patterns.
. .....
~ .
. : ' : . - - . , . :.. -.. .. , :~ .. , - . .
' ' . . ' ''' . '.' '' "' " ' ' ' ' ' .
Claims (9)
1) A microwave filter comprising a plurality of resonant cavities coupled together in a series between an input and an output at opposite ends of the filter, the cavities being arranged in two parallel sub-series with the signal path proceeding from the input to a first cavity in one sub-series, then to a first cavity in the second sub-series, then to a second cavity in the second sub-series, then to a second cavity in the first sub-series, and so on up to the output.
2) A filter as claimed in claim 1 in which the input and output of the filter face in opposite directions.
3) A filter as claimed in claims 1 in which the two sub-series of resonant cavities are separated by a common partition wall.
4) A filter as claimed in claim 1 in which adjacent cavities in each sub-series are separated by partition walls.
5) A filter as claimed in claim 4 in which the adjacent cavities in the same sub-series are coupled by means of an iris in the respective partition wall.
6) A filter as claimed in claim 5 in which the iris is offset towards a first side of the filter.
7) A filter as claimed in claim 3 in which a cavity of one sub-series and a cavity of the other sub-series are coupled by means of an iris in the common partition wall between these cavities.
8) A filter as claimed in claim 7 in which the iris is offset towards a second side of the filter.
9) A filter as claimed in claim 7 in which the iris is adjacent one of the sub-series partition walls.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB919114969A GB9114969D0 (en) | 1991-07-11 | 1991-07-11 | Inline folded microwave filter |
| GB9114969.0 | 1991-07-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2054996A1 true CA2054996A1 (en) | 1993-01-12 |
Family
ID=10698186
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2054996 Abandoned CA2054996A1 (en) | 1991-07-11 | 1991-11-06 | In-line folded microwave filter |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU8571791A (en) |
| CA (1) | CA2054996A1 (en) |
| GB (1) | GB9114969D0 (en) |
-
1991
- 1991-07-11 GB GB919114969A patent/GB9114969D0/en active Pending
- 1991-10-09 AU AU85717/91A patent/AU8571791A/en not_active Abandoned
- 1991-11-06 CA CA 2054996 patent/CA2054996A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| GB9114969D0 (en) | 1991-08-28 |
| AU8571791A (en) | 1993-01-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |