EP0525416B1 - Microwave filter - Google Patents
Microwave filter Download PDFInfo
- Publication number
- EP0525416B1 EP0525416B1 EP92111098A EP92111098A EP0525416B1 EP 0525416 B1 EP0525416 B1 EP 0525416B1 EP 92111098 A EP92111098 A EP 92111098A EP 92111098 A EP92111098 A EP 92111098A EP 0525416 B1 EP0525416 B1 EP 0525416B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coupling
- conductor
- coaxial resonators
- microwave filter
- coaxial
- 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 - Lifetime
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- 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
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/205—Comb or interdigital filters; Cascaded coaxial cavities
- H01P1/2053—Comb or interdigital filters; Cascaded coaxial cavities the coaxial cavity resonators being disposed parall to each other
Definitions
- the present invention relates to a microwave filter, consisting of at least three coaxial resonators, each of which is coupled to its adjacent coaxial resonator via a coupling opening in the common partition, the coaxial resonators being strung together along an angled line.
- Such a microwave filter is known from DE-AS 21 61 792.
- coaxial resonators which are directly adjacent to one another are coupled via coupling pins which are held in coupling openings by means of dielectric disks. Special measures must often be taken to ensure that a filter has the desired flank profiles.
- So z. B. in a known from DE-PS 22 18 277 filter with rectilinearly arranged coaxial resonators extending outside the resonators coupling line between non-adjacent resonators is provided in order to achieve a flank symmetry of the damping curve.
- the invention is based on the object of specifying a microwave filter of the type mentioned in the introduction, in which a desired flank profile of the damping curve can be realized with simple space-saving means.
- this object is achieved by the features of claim 1. Accordingly, only a conductor arranged in the interior of the filter is required in order to implement the desired edge profiles of the damping curve. This advantageously does not increase the space requirement of the filter.
- FIG. 1 shows a three-circuit microwave filter, consisting of three coaxial resonators K1, K2 and K3, the inner conductors of which are designated I1, I2 and I3.
- the drawing shows that the coaxial resonators K1, K2 and K3 have a square cross section.
- the invention is not limited to square coaxial resonators, but allows any other resonator cross section.
- the coaxial resonators are lined up along an angled line, the angling also being able to deviate from 90 °.
- the partitions between the individual coaxial resonators K1, K2 and K3 are provided with inductively acting coupling openings KS1 and KS2.
- these coupling openings KS1 and KS2 lead to undesirable inductive coupling between the mutually angled, mutually angled coaxial resonators K1 and K3.
- This parasitic inductive coupling causes an asymmetry in the edge curves of the filter damping curve.
- This damping curve 1 can be seen in FIG. 2.
- an additional capacitive coupling between the individual coaxial resonators K1, K2 and K3 is provided in addition to the inductive coupling.
- This additional capacitive coupling which is not absolutely necessary, is realized with the aid of coupling pins S12 and S23, which are arranged in the coupling openings KS1 and KS2 and protrude into the adjacent coaxial resonators K1, K2 and K3.
- These coupling pins S12 and S23 are held by dielectric disks F1 and F2 inserted into the coupling opening KS1 and KS2.
- the degree of capacitive coupling depends on the length and the cross-sectional geometry of the coupling pins S12 and S23.
- the above-mentioned parasitic inductive coupling between the coaxial resonators K1 and K3 can be compensated for by a conductor L which extends in the shortest possible way through the coaxial resonator K2 arranged between the two mutually angled coaxial resonators K1 and K3 and the ends of which through the coupling opening KS1 and KS2 in said coaxial resonators K1 and K3 protrude into it.
- the capacitive couplings caused by this conductor L depend on the cross-sectional geometry and the depth of penetration of the conductor ends into the coaxial resonators K1 and K2.
- the flanks of the damping curve shift to such an extent that there is a symmetrical course, as shown by the dashed curve 2 in FIG .
- the flanks of the damping curve can also be given a course deviating from the symmetry, if this is desired for certain applications. It can be seen from FIG. 2 that the capacitive coupling of the conductor L relates only to the edge profiles in the area of high damping, but in the area of low damping the damping curve remains unaffected.
- the invention has been described above using a three-circuit microwave filter. But it can also be used effectively for filters with more than just three circles.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Description
Die vorliegende Erfindung betrifft ein Mikrowellenfilter, bestehend aus mindestens drei Koaxialresonatoren, von denen jeder mit seinem jeweils benachbarten Koaxialresonator über eine Koppelöffnung in der gemeinsamen Trennwand gekoppelt ist, wobei die Koaxialresonatoren entlang einer abgewinkelten Linie aneinandergereiht sind.The present invention relates to a microwave filter, consisting of at least three coaxial resonators, each of which is coupled to its adjacent coaxial resonator via a coupling opening in the common partition, the coaxial resonators being strung together along an angled line.
Ein derartiges Mikrowellenfilter ist aus der DE-AS 21 61 792 bekannt. Bei diesem Filter sind einander direkt benachbarte koaxiale Resonatoren über Koppelstifte, die in Koppelöffnungen mittels dielektrischer Scheiben gehalten werden, gekoppelt. Damit ein Filter die gewünschten Flankenverläufe aufweist, sind oft besondere Maßnahmen zu ergreifen. So ist z. B. bei einem aus der DE-PS 22 18 277 bekannten Filter mit geradlinig angeordneten Koaxialresonatoren eine außerhalb der Resonatoren verlaufende Koppelleitung zwischen nicht benachbarten Resonatoren vorgesehen, um eine Flankensymmetrierung der Dämpfungskurve zu erzielen.Such a microwave filter is known from DE-AS 21 61 792. In this filter, coaxial resonators which are directly adjacent to one another are coupled via coupling pins which are held in coupling openings by means of dielectric disks. Special measures must often be taken to ensure that a filter has the desired flank profiles. So z. B. in a known from DE-PS 22 18 277 filter with rectilinearly arranged coaxial resonators extending outside the resonators coupling line between non-adjacent resonators is provided in order to achieve a flank symmetry of the damping curve.
Der Erfindung liegt nun die Aufgabe zugrunde, ein Mikrowellenfilter der eingangs genannten Art anzugeben, bei dem mit einfachen raumsparenden Mitteln ein gewünschter Flankenverlauf der Dämpfungskurve realisiert werden kann.The invention is based on the object of specifying a microwave filter of the type mentioned in the introduction, in which a desired flank profile of the damping curve can be realized with simple space-saving means.
Erfindungsgemäß wird diese Aufgabe durch die Merkmale des Anspruchs 1 gelöst. Demnach ist lediglich ein im Innern des Filters angeordneter Leiter erforderlich, um gewünschte Flankenverläufe der Dämpfungskurve zu verwirklichen. Der Platzbedarf des Filters erhöht sich dadurch vorteilhafterweise nicht.According to the invention, this object is achieved by the features of claim 1. Accordingly, only a conductor arranged in the interior of the filter is required in order to implement the desired edge profiles of the damping curve. This advantageously does not increase the space requirement of the filter.
Zweckmäßige Ausführungen und Weiterbildungen der Erfindung gehen aus den Unteransprüche hervor.Appropriate embodiments and developments of the invention emerge from the subclaims.
Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels wird nachfolgend die Erfindung näher erläutert.
- Fig. 1
- zeigt ein dreikreisiges Filter und
- Fig. 2
- zeigt zwei Dämpfungskurven des Filters.
- Fig. 1
- shows a three-circuit filter and
- Fig. 2
- shows two attenuation curves of the filter.
In der Figur 1 ist ein dreikreisiges Mikrowellenfilter dargestellt, bestehend aus drei koaxialen Resonatoren K1, K2 und K3, dessen Innenleiter mit I1, I2 und I3 bezeichnet sind. Der Zeichnung ist zu entnehmen, daß die koaxialen Resonatoren K1, K2 und K3 einen quadratischen Querschnitt haben. Die Erfindung ist aber nicht auf quadratische Koaxialresonatoren beschränkt, sondern läßt jeden anderen Resonatorquerschnitt zu.1 shows a three-circuit microwave filter, consisting of three coaxial resonators K1, K2 and K3, the inner conductors of which are designated I1, I2 and I3. The drawing shows that the coaxial resonators K1, K2 and K3 have a square cross section. However, the invention is not limited to square coaxial resonators, but allows any other resonator cross section.
Bei dem dieser Anmeldung zugrundeliegenden Mikrowellenfilter sind die Koaxialresonatoren entlang einer abgewinkelten Linie aneinandergereiht, wobei die Abwinklung auch von 90° abweichen kann. Die Trennwände zwischen den einzelnen Koaxialresonatoren K1, K2 und K3 sind mit induktiv wirkenden Koppelöffnungen KS1 und KS2 versehen. Durch diese Koppelöffnungen KS1 und KS2 kommt es aber zu unerwünschten induktiven Überkopplungen zwischen den einander nicht benachbarten, gegenseitig abgewinkelten Koaxialresonatoren K1 und K3. Diese parasitäre induktive Kopplung ruft eine Unsymmetrie der Flankenverläufe der Filter-Dämpfungskurve hervor. Diese Dämpfungskurve 1 kann man der Figur 2 entnehmen.In the microwave filter on which this application is based, the coaxial resonators are lined up along an angled line, the angling also being able to deviate from 90 °. The partitions between the individual coaxial resonators K1, K2 and K3 are provided with inductively acting coupling openings KS1 and KS2. However, these coupling openings KS1 and KS2 lead to undesirable inductive coupling between the mutually angled, mutually angled coaxial resonators K1 and K3. This parasitic inductive coupling causes an asymmetry in the edge curves of the filter damping curve. This damping curve 1 can be seen in FIG. 2.
Bei dem in der Figur 1 dargestellten Mikrowellenfilter ist neben der induktiven Kopplung noch eine kapazitive Zusatzkopplung zwischen den einzelnen Koaxialresonatoren K1, K2 und K3 vorgesehen. Diese nicht unbedingt erforderliche kapazitive Zusatzkopplung wird mit Hilfe von Koppelstiften S12 und S23 verwirklicht, die in den Koppelöffnungen KS1 und KS2 angeordnet sind und in die benachbarten Koaxialresonatoren K1, K2 und K3 hineinragen. Gehalten werden diese Koppelstifte S12 und S23 durch in die Koppelöffnung KS1 und KS2 eingesetzte dielektrische Scheiben F1 und F2. Der Grad der kapazitiven Kopplung hängt von der Länge und der Querschnittsgeometrie der Koppelstifte S12 und S23 ab.In the microwave filter shown in FIG. 1, an additional capacitive coupling between the individual coaxial resonators K1, K2 and K3 is provided in addition to the inductive coupling. This additional capacitive coupling, which is not absolutely necessary, is realized with the aid of coupling pins S12 and S23, which are arranged in the coupling openings KS1 and KS2 and protrude into the adjacent coaxial resonators K1, K2 and K3. These coupling pins S12 and S23 are held by dielectric disks F1 and F2 inserted into the coupling opening KS1 and KS2. The degree of capacitive coupling depends on the length and the cross-sectional geometry of the coupling pins S12 and S23.
Die zuvor angesprochene parasitäre induktive Kopplung zwischen den Koaxialresonatoren K1 und K3 kann durch einen Leiter L kompensiert werden, der sich auf kürzestem Wege durch den zwischen den beiden gegeneinander abgewinkelten Koaxialresonatoren K1 und K3 angeordneten Koaxialresonator K2 erstreckt und dessen Enden durch die Koppelöffnung KS1 und KS2 in die besagten Koaxialresonatoren K1 und K3 hineinragen. Die durch diesen Leiter L bewirkten kapazitiven Kopplungen hängen von der Querschnittsgeometrie und der Eindringtiefe der Leiterenden in die Koaxialresonatoren K1 und K2 ab. Wird der Leiter L so stark an die Koaxialresonatoren K1 und K2 kapazitiv angekoppelt, daß gerade die parasitäre induktive Überkopplung kompensiert wird, so verschieben sich die Flanken der Dämpfungskurve soweit, daß es zu einem symmetrischen Verlauf kommt, wie die strichlierte Kurve 2 in Figur 2 zeigt. Bei entsprechender Wahl der kapazitiven Ankopplung des Leiters L an die Koaxialresonatoren K1 und K2 kann den Flanken der Dämpfungskurve auch ein von der Symmetrie abweichender Verlauf verliehen werden, sofern das für gewisse Anwendungsfälle gewünscht ist. Der Figur 2 kann man entnehmen, daß sich die kapazitive Kopplung des Leiters L nur auf die Flankenverläufe im Bereich hoher Dämpfung auswirkt, im Bereich niederer Dämpfung die Dämpfungskurve aber unbeeinflußt bleibt.The above-mentioned parasitic inductive coupling between the coaxial resonators K1 and K3 can be compensated for by a conductor L which extends in the shortest possible way through the coaxial resonator K2 arranged between the two mutually angled coaxial resonators K1 and K3 and the ends of which through the coupling opening KS1 and KS2 in said coaxial resonators K1 and K3 protrude into it. The capacitive couplings caused by this conductor L depend on the cross-sectional geometry and the depth of penetration of the conductor ends into the coaxial resonators K1 and K2. If the conductor L is capacitively coupled to the coaxial resonators K1 and K2 in such a way that the parasitic inductive coupling is compensated for, the flanks of the damping curve shift to such an extent that there is a symmetrical course, as shown by the dashed curve 2 in FIG . With a suitable choice of the capacitive coupling of the conductor L to the coaxial resonators K1 and K2, the flanks of the damping curve can also be given a course deviating from the symmetry, if this is desired for certain applications. It can be seen from FIG. 2 that the capacitive coupling of the conductor L relates only to the edge profiles in the area of high damping, but in the area of low damping the damping curve remains unaffected.
Vorangehend wurde die Erfindung anhand eines dreikreisigen Mikrowellenfilters beschrieben. Sie kann aber auch für Filter mit mehr als nur drei Kreisen wirksam eingesetzt werden.The invention has been described above using a three-circuit microwave filter. But it can also be used effectively for filters with more than just three circles.
Claims (4)
- Microwave filter, consisting of at least three coaxial resonators, each of which is coupled to its respectively adjacent coaxial resonator via a coupling aperture in the common separating wall, the coaxial resonators being arranged sequentially along an angled line, characterized in that a conductor (L) extends through the cavity of such a coaxial resonator (K2) which is coupled to two coaxial resonators (K1, K3) angled off from one another, the ends of which conductor project through the coupling apertures (KS1, KS2) into the coaxial resonators (K1, K3), angled off with respect to one another and adjacent to this conductor, and in that the penetration depth of the conductor ends and their cross-sectional geometry are chosen such that the edges of the filter attenuation curve assume a desired profile.
- Microwave filter according to Claim 1, characterized in that dielectric discs (F1, F2) are placed in the coupling apertures (KS1, KS2), through which discs the ends of the conductor (L) are inserted in order to be held.
- Microwave filter according to Claim 1, characterized in that in each case two adjacent coaxial resonators (K1, K2) are capacitively coupled by a coupling pin (S12, S23) placed in their common coupling aperture (KS1, KS2).
- Microwave filter according to Claim 1 and 3, characterized in that the coupling pin (S12, S23) is located in the dielectric disc (F1, F2) of the coupling aperture (KS1, KS2).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4125060 | 1991-07-29 | ||
| DE4125060 | 1991-07-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0525416A1 EP0525416A1 (en) | 1993-02-03 |
| EP0525416B1 true EP0525416B1 (en) | 1995-10-18 |
Family
ID=6437229
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92111098A Expired - Lifetime EP0525416B1 (en) | 1991-07-29 | 1992-07-01 | Microwave filter |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0525416B1 (en) |
| DE (1) | DE59204046D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1791212A1 (en) | 2005-11-28 | 2007-05-30 | Matsushita Electric Industrial Co., Ltd. | Microwave filters including a capacitive coupling element |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19623144A1 (en) * | 1996-06-10 | 1997-12-11 | Bosch Gmbh Robert | Microwave filter, consisting of several coaxial resonators |
| KR100624048B1 (en) * | 1999-01-29 | 2006-09-18 | 도꼬가부시끼가이샤 | Dielectric filter |
| FI114251B (en) | 2000-09-22 | 2004-09-15 | Filtronic Lk Oy | resonator filter |
| JP3902072B2 (en) | 2001-07-17 | 2007-04-04 | 東光株式会社 | Dielectric waveguide filter and its mounting structure |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB780231A (en) * | 1953-01-10 | 1957-07-31 | Standard Telephones Cables Ltd | Electromagnetic wave filters of large bandwidth |
| CH532864A (en) * | 1971-07-05 | 1973-01-15 | Hirschmann Electric | Arrangement with coaxial cup circles, the mutual coupling of which is adjustable |
| DE2640210C3 (en) * | 1976-09-07 | 1979-05-03 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Filter for very short electromagnetic waves |
| DE3028925A1 (en) * | 1980-07-30 | 1982-02-11 | Siemens AG, 1000 Berlin und 8000 München | Quarter wave branch connector for HF aerials - has junction with coupling loops at input resonators of twin parallel filters |
| FR2509535A1 (en) * | 1981-07-07 | 1983-01-14 | Thomson Csf | Coupled line section tunable microwave filter - has parallel resonators extending across rectangular resonant cavity and tuning provided by variable capacitor |
-
1992
- 1992-07-01 DE DE59204046T patent/DE59204046D1/en not_active Expired - Fee Related
- 1992-07-01 EP EP92111098A patent/EP0525416B1/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1791212A1 (en) | 2005-11-28 | 2007-05-30 | Matsushita Electric Industrial Co., Ltd. | Microwave filters including a capacitive coupling element |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0525416A1 (en) | 1993-02-03 |
| DE59204046D1 (en) | 1995-11-23 |
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