EP0029276A1 - Microwave filter - Google Patents
Microwave filter Download PDFInfo
- Publication number
- EP0029276A1 EP0029276A1 EP80201088A EP80201088A EP0029276A1 EP 0029276 A1 EP0029276 A1 EP 0029276A1 EP 80201088 A EP80201088 A EP 80201088A EP 80201088 A EP80201088 A EP 80201088A EP 0029276 A1 EP0029276 A1 EP 0029276A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- band
- partition
- waveguide
- slots
- partitions
- 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.)
- Granted
Links
- 238000005192 partition Methods 0.000 claims abstract description 29
- 230000001939 inductive effect Effects 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
Images
Classifications
-
- 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
- H01P1/207—Hollow waveguide filters
- H01P1/209—Hollow waveguide filters comprising one or more branching arms or cavities wholly outside the main waveguide
-
- 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
- H01P1/207—Hollow waveguide filters
- H01P1/208—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure
-
- 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
- H01P1/2138—Frequency-selective devices, e.g. filters combining or separating two or more different frequencies using hollow waveguide filters
Definitions
- Fig. 5 shows the connection between the attenuation and the frequency for each of the partitions 7 and 8 (curves 15 and 16) and for the combination of the two partitions (curve 15 + 16)in the pass range of the band of 11.35 - 11.8 GHz. In this band the attenuation is only very little larger than for each separate partition.
Landscapes
- Control Of Motors That Do Not Use Commutators (AREA)
- Control And Other Processes For Unpacking Of Materials (AREA)
- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
Abstract
Description
- The invention relates to a microwave filter formed by a transverse partition mounted in a waveguide, which partition is provided with some parallel slot-shaped apertures of different lengths.
- A microwave filter of this type is known from the British patent specification 649,301.
- The known filter relates to a polarization filter and therefore the lengths of the slots are not significant.
- The known filter is only useful for waves which are orthogonally polarized.
- Microwave filters generally consist of elements which have a capacitive or an inductive behaviour. These elements can be:
- - A local narrowing of the waveguide (the long or a-dimension smaller), which has an inductive effect.
- - A local lowering of the waveguide (the short or b-dimension smaller), which has a capacitive effect.
- - Pins transversely mounted in the waveguide, which has an inductive effect, and
- - Transverse partitions with a slot or with a round hole, which has a capacitive and an inductive effect.
- By mounting two similar elements at a distance of λ in a waveguide a resonant cavity is formed. This resonant cavity can be compared with a resonant circuit, so a filter consisting of one circuit. In case several resonant cavities are arranged in a waveguide at a distance of 4 between them, this involves that certain desirable properties can be attributed to the filter. Filters consisting of inductive and/or of capacitive elements have a band-pass character.
- A drawback of these filters is that a band-pass behaviour can also occur higher up in the frequency band. This is an undesirable circumstance in many cases when said filters are made use of, e.g. when in a system the transmitting and receiving frequencies have to be separated. When in a receiving system the parasitic pass band is at the transmitting frequency, the entrance of transmission signals into the receiver can be prevented by mounting band-stop filters. The band-stop filters generally used consist of resonant circuits coupled in parallel to a waveguide. These filters are voluminous and making them is costly.
- The object of the invention is to provide a filter which has on the one hand a band-pass character, e.g. for a receiving band, and on the other hand a band-stop character for a transmitting band. This is achieved because of the fact that the length of the longest slot is equal to about half the wavelength of the centre frequency of the pass band. The longest slot yields the band-pass character with a low Q. The. short slots have a length of half the wavelength for a frequency higher than the band to be stopped. The entire combination of slots gives a resonance phenomenon at an interjacent frequency, which results in a stop-band attenuation with a maximum of c. 50 dB.
- The filter according to the invention can often be a very good substitute for the band-stop filters of the conventional type. The use of the filter according to the invention disposes of the drawbacks attended with the conventional filters. A very striking aspect is that the cost of production is considerably lower. The filter according to the invention can be utilized in a special way when the transverse partition forms the wall between two coupled waveguides. Stopping the undesirable overflow of signals can now take place in the coupling area of the connection.
- The invention will be elucidated below by means of some examples of the utilization of the invention elaborated with the help of the drawing; in which
- Fig. 1 illustrates an output system at the beginning of a receiving circuit;
- Fig. 2 shows a side-view of a filter consisting of two partitions;
- Fig. 3,4 show views of the two partitions;
- Fig. 5 represents a dB-f diagram for the pass band, and
- Fig. 6 represents a dB-f diagram for the stop band.
- The output system according to Fig. is part of the waveguide circuit used for Orbital Test Satellite (OTS) experiments. The wall of a
round waveguide 1 is provided with fourslot combinations 2, to which thewaveguides 3 are connected, which in their turn are connected to a receiving system. Oneend 4 of thewaveguide 1 is connected to an aerial; theother end 5 is connected to a transmitter. Thepart 6 between theslot combinations 2 and theend 5 is made narrow and forms a short-circuit for the received signals. - The filter according to Figs. 2 - 4 comprises two
partitions slot combination 2 is then formed by apartition 7, and apartition 8 is mounted in each of the fourwaveguides 3. This configuration is chosen when a broad transmission band has to be stopped. Thepartition 7 has along slot 9 and twoshort slots partition 8 also has along slot 12 and twoshort slots partition 8 are somewhat shorter than those of thepartition 7. The distance between thepartitions slots - Fig. 5 shows the connection between the attenuation and the frequency for each of the
partitions 7 and 8 (curves 15 and 16) and for the combination of the two partitions (curve 15 + 16)in the pass range of the band of 11.35 - 11.8 GHz. In this band the attenuation is only very little larger than for each separate partition. - Fig. 6 also shows the connection between the attenuation and the frequency for the
partitions curves 17 and 18) and for the combination of the two partitions (curve 17 + 18) in the range around the stop frequency of 14.551 GHz. It appears that for each separate partition the attenuation at the stop frequency amounts to at least 20 dB, whereas the combination of the two partitions yields an attenuation of 50 dB. - As a third possibility of utilizing the invention can be mentioned a band-stop filter with more than two partitions arranged behind each other, in consequence of which every passage in a large stop range will be completely impossible because of the high pass-band attenuation.
- As already stated the filter according to the invention is, in addition to its better properties, much more attractive than the usual band filters.with resonant cavities, which are difficult to make.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT80201088T ATE7437T1 (en) | 1979-11-15 | 1980-11-14 | MICROWAVE FILTER. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7908374 | 1979-11-15 | ||
NLAANVRAGE7908374,A NL181064C (en) | 1979-11-15 | 1979-11-15 | MICROWAVE FILTER. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0029276A1 true EP0029276A1 (en) | 1981-05-27 |
EP0029276B1 EP0029276B1 (en) | 1984-05-09 |
Family
ID=19834190
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP80201088A Expired EP0029276B1 (en) | 1979-11-15 | 1980-11-14 | Microwave filter |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0029276B1 (en) |
AT (1) | ATE7437T1 (en) |
DE (1) | DE3067782D1 (en) |
NL (1) | NL181064C (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0045242A1 (en) * | 1980-07-22 | 1982-02-03 | Thomson-Csf | Microwave pass-band filter in a waveguide |
FR2577719A1 (en) * | 1985-02-15 | 1986-08-22 | Alcatel Espace | POLARIZATION DUPLEXER |
US5087440A (en) * | 1989-07-31 | 1992-02-11 | Salutar, Inc. | Heterocyclic derivatives of DTPA used for magnetic resonance imaging |
WO1997002619A1 (en) * | 1995-06-30 | 1997-01-23 | Daimler-Benz Aerospace Ag | Waveguide filter |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4008770A1 (en) * | 1990-03-19 | 1991-09-26 | Ant Nachrichtentech | Cavity resonator with TE wave-type coupling - provided by slot in side wall of cylinder |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB649301A (en) * | 1948-06-29 | 1951-01-24 | Mini Of Supply | Improvements in or relating to ultra high frequency radio apparatus employing wave guides |
GB773527A (en) * | 1953-10-09 | 1957-04-24 | British Thomson Houston Co Ltd | Improvements in and relating to waveguides |
US3952270A (en) * | 1974-01-25 | 1976-04-20 | Compagnie Industrielle Des Telecommunications Cit-Alcatel | Hyperfrequency band-cut filter |
-
1979
- 1979-11-15 NL NLAANVRAGE7908374,A patent/NL181064C/en not_active IP Right Cessation
-
1980
- 1980-11-14 DE DE8080201088T patent/DE3067782D1/en not_active Expired
- 1980-11-14 AT AT80201088T patent/ATE7437T1/en not_active IP Right Cessation
- 1980-11-14 EP EP80201088A patent/EP0029276B1/en not_active Expired
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB649301A (en) * | 1948-06-29 | 1951-01-24 | Mini Of Supply | Improvements in or relating to ultra high frequency radio apparatus employing wave guides |
GB773527A (en) * | 1953-10-09 | 1957-04-24 | British Thomson Houston Co Ltd | Improvements in and relating to waveguides |
US3952270A (en) * | 1974-01-25 | 1976-04-20 | Compagnie Industrielle Des Telecommunications Cit-Alcatel | Hyperfrequency band-cut filter |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0045242A1 (en) * | 1980-07-22 | 1982-02-03 | Thomson-Csf | Microwave pass-band filter in a waveguide |
FR2577719A1 (en) * | 1985-02-15 | 1986-08-22 | Alcatel Espace | POLARIZATION DUPLEXER |
EP0192186A1 (en) * | 1985-02-15 | 1986-08-27 | Alcatel Espace | Polarisation duplexer |
US5087440A (en) * | 1989-07-31 | 1992-02-11 | Salutar, Inc. | Heterocyclic derivatives of DTPA used for magnetic resonance imaging |
WO1997002619A1 (en) * | 1995-06-30 | 1997-01-23 | Daimler-Benz Aerospace Ag | Waveguide filter |
US6340922B1 (en) | 1995-06-30 | 2002-01-22 | Daimlerchrysler Aerospace Ag | Waveguide filter with three apertures for passing transmission frequencies and blocking interference frequencies |
Also Published As
Publication number | Publication date |
---|---|
NL181064C (en) | 1987-06-01 |
ATE7437T1 (en) | 1984-05-15 |
DE3067782D1 (en) | 1984-06-14 |
NL181064B (en) | 1987-01-02 |
NL7908374A (en) | 1981-06-16 |
EP0029276B1 (en) | 1984-05-09 |
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Legal Events
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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ITCL | It: translation for ep claims filed |
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TCAT | At: translation of patent claims filed | ||
DET | De: translation of patent claims | ||
17P | Request for examination filed |
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