EP1895615A1 - Einstellbare Kopplung - Google Patents

Einstellbare Kopplung Download PDF

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Publication number
EP1895615A1
EP1895615A1 EP06119880A EP06119880A EP1895615A1 EP 1895615 A1 EP1895615 A1 EP 1895615A1 EP 06119880 A EP06119880 A EP 06119880A EP 06119880 A EP06119880 A EP 06119880A EP 1895615 A1 EP1895615 A1 EP 1895615A1
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EP
European Patent Office
Prior art keywords
elongate portion
elongate
bore
coupling element
filter according
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.)
Withdrawn
Application number
EP06119880A
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English (en)
French (fr)
Inventor
Micheal Hoeft
Ramon Sobrido
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to EP06119880A priority Critical patent/EP1895615A1/de
Publication of EP1895615A1 publication Critical patent/EP1895615A1/de
Withdrawn legal-status Critical Current

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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 comprising at least one resonator having electrically conductive walls defining a resonator cavity and a coupling mechanism for coupling electromagnetic energy into or out of the resonator cavity, wherein the coupling mechanism comprises a through bore through a wall portion of the resonator extending transversely to the wall portion, an electrically conductive coupling element extending through the through bore and comprising a first elongate portion adjacent the opening of the through bore into the resonator cavity and a second elongate portion adjacent the opposite opening of the through bore, wherein the first elongate portion projects at least partly into the resonator cavity, a dielectric mounting for securing the coupling element in the through bore such that the coupling element is electrically isolated form the wall portion, and an adjustment means operable to selectively change the coupling characteristics of the coupling mechanism.
  • the microwave region of the electromagnetic spectrum finds widespread use in various fields of technology. Exemplary applications include wireless communication systems, such as mobile communication and satellite communication systems, as well as navigation and radar technology.
  • the growing number of microwave applications increases the possibility of interference occurring within a system or between different systems. Therefore, the microwave region is divided into a plurality of distinct frequency bands.
  • microwave filters are utilized to perform band-pass and band reject functions during transmission and/or reception. Accordingly, the filters are used to separate the different frequency bands and to discriminate between wanted and unwanted signal frequencies so that the quality of the received and of the transmitted signals is largely governed by the characteristics of the filters. Commonly, the filters have to provide for a small bandwidth and a high filter quality.
  • microwave filters include a plurality of resonators or resonant sections which are coupled together in various configurations.
  • Each such resonator usually comprises a space contained within a closed or substantially closed conducting surface.
  • an oscillating electromagnetic field may be maintained within this space or resonator cavity.
  • the resonators exhibit marked resonance effects and are characterized by the respective resonant frequency and band-width.
  • electromagnetic energy has to be coupled into and out of the filter and between the individual resonators of the filter.
  • the easiest way to achieve coupling between the resonators is the provision of an aperture in the wall between adjacent resonators which usually leads to magnetic coupling between these resonators. Therefore, the main way of coupling between the resonators is usually realized as magnetic coupling by means of coupling apertures.
  • Such electric coupling between two resonators may be achieved by provision of a capacitive coupling element which may comprise an elongated portion or pin.
  • the coupling element is held in a dielectric mounting to avoid contact with the conductive walls of the resonator cavities.
  • the mounting is placed in an opening cut out from an end of the side wall separating the two adjacent resonators.
  • the elongated portion or pin extends into both cavities and provides electric coupling.
  • Such arrangement is for example described in DE 196 02 815 A1 .
  • a similar arrangement is described in EP 0 525 416 B1 .
  • a coupling element may be provided with enlarged diameter end portions or disks at both ends of the elongated pin portion.
  • Such coupling elements are for example disclosed in DE 21 61 792 A1 .
  • the distinct resonators coupled together to form the filter have a predetermined resonant frequency.
  • novel base station systems based on "software defined radio" should have as large a tuning range for all filter parameters as possible. This relates especially to tuning of the center frequencies of the resonators for switching the filter into other operational bands and to tuning of the coupling values due to changes of the fields inside the resonators at different frequencies.
  • US 6,150,907 discloses a coupling mechanism for coupling electromagnetic energy between the resonator cavities of two coupled TE 001 or TE 01 ⁇ resonators, which coupling mechanism allows for adjustment of the magnitude and/or phase of the electromagnetic energy.
  • the coupling mechanism comprises an elongate coupling element, which may be a dielectric rod or a conductive filament, and which passes through adjacent side walls of the coupled resonators and projects into both resonator cavities.
  • Adjustment of the coupling characteristics is effected by shifting the entire coupling element as a whole along the axial direction of the two adjacent resonators, by rotating the entire coupling element as a whole about an axis perpendicular to the plane in which the coupling element extends, by bending the portions of the elongate coupling element projecting into the resonator cavities, or by a combination thereof.
  • US 6,924,718 B2 discloses a microwave filter comprising a plurality of electromagnetically coupled resonators, wherein at least two adjacent resonators are coupled by means of an elongate capacitive probe or an elongate inductive probe extending through the common side wall separating the cavities of the two resonators.
  • the probe projects into both resonator cavities and is fixedly secured in the side wall, so that it is stationary.
  • the elongate probe comprises a transverse bore located in the portion of the probe disposed within the side wall.
  • a movable tuning conductor is received in the transverse bore and extends in the plane defined by the side wall, i.e. the tuning conductor does not project into any of the resonator cavities.
  • the coupling characteristics of the probe may be adjusted by moving the tuning conductor within the plane defined by the side wall.
  • a microwave filter according to the present invention comprises at least one resonator having electrically conductive walls defining a resonator cavity and a coupling mechanism for coupling electromagnetic energy into or out of the resonator cavity.
  • the walls may be made of a conductive material or may be made of a dielectric material plated with a conductive material.
  • the coupling mechanism comprises a through bore extending through a wall portion of the resonator, which through bore extends transversely to the wall portion.
  • This through bore is preferably straight, but may also be curved.
  • the direction of extension of the through bore is understood as the direction from one opening of the through bore along the through bore to the opposite opening of the though bore.
  • the coupling mechanism further comprises a coupling element.
  • This coupling element extends through the through bore and comprises a first elongate portion adjacent the opening of the through bore into the resonator cavity and a second elongate portion adjacent the opposite opening of the through bore.
  • the first elongate portion projects at least partly into the resonator cavity, whereas the second elongate portion may or may not project from the opening of the though bore on the side of the wall portion opposite the resonator cavity.
  • the first and the second elongate portion are electrically conductive.
  • the coupling element is constructed such that electromagnetic energy coupled into one of the elongate portions is transferred to the second elongate portion. In this way, electromagnetic energy can be coupled from the outside into the resonator cavity and vice versa.
  • the elongate portions are preferably rigid, but may also be flexible.
  • a dielectric mounting of the coupling mechanism is provided for securing the coupling element in the wall portion such that the coupling element is electrically isolated from the wall portion.
  • This dielectric mounting may be arranged as an element in a larger through bore formed in the wall portion, i.e. as an element only partly filling a through bore formed in the wall portion, or the dielectric mounting may be disposed in a cut-out region of the wall portion with the through bore being provided in the dielectric mounting.
  • the through bore extends through the wall portion, but is formed in the dielectric mounting, which itself can be regarded as forming a part of the wall portion.
  • the through bore extending through the wall portion is to be understood as meaning that the through bore provides a path from one side of the wall portion to the other side of the wall portion.
  • the coupling mechanism comprises an adjustment means that is adapted to allow for a selective change of the coupling characteristics of the coupling mechanism, such as for a change of the coupling strength.
  • the adjustment means is adapted to cooperate with or act on the coupling element in such a manner that it is possible to displace the first elongate portion and the second elongate portion of the coupling element with respect to each other to thereby selectively advance the first elongate portion from the through bore further into the resonator cavity or further retract the first elongate portion from the resonator cavity into the through bore.
  • This means that it is possible to operate the adjustment means in order to increase or decrease, at the operator's option according to the requirements and to the desired change of coupling characteristics, the length of the part of the first elongate portion projecting from the through bore into the resonator cavity.
  • first elongate portion and the second elongate portion may be separate, physically distinct members or parts which, possibly in combination with additional members or parts, together form the coupling element, or the first elongate portion and the second elongate portion may be sections of one integral piece which, alone or together with additional members or parts, forms the coupling element.
  • the adjustment means is adapted to change the length of the path defined by (a) starting from the outer terminal end of the first elongate portion disposed in the resonator cavity along the first elongate portion to the opening of the through bore into the resonator cavity, (b) then from this opening following the direction of extension of the through bore to, depending on whether or not the second elongate portion projects from the through bore, the location of the outer terminal end of the second elongate portion in the through bore or the opposite opening of the through bore, and (c), in case the second elongate portion projects from this opening, from the opening along the second elongate portion to the outer terminal end of the second elongate portion.
  • the adjustment means is adapted to change the length of a central portion of the coupling element.
  • the first and the second elongate portion are the terminal end portions of the coupling element, the central portion spans the entire coupling element, so that in this case the length of the entire coupling element, understood in the above sense, can be changed, and the coupling element can selectively be gradually extended or shortened in its overall length.
  • further elements such as e.g. capacitive disks or inductive wires, are secured to the outer ends of the elongate portions.
  • the capability of coupling electromagnetic energy from one of the two elongate portions to the other may preferably be realized by providing an electrical connection between the two elongate portions.
  • the first elongate portion and the second elongate portion may be separated by a dielectric portion of the coupling element such that capacitive coupling is realized.
  • a dielectric portion could e.g. comprise ceramic material to provide a large relative permittivity.
  • This coupling mechanism can be an input or output coupling mechanism for coupling electromagnetic energy from the exterior of the filter into a resonator or from a resonator to the exterior of the filter. Further, in case the filter comprises more than one resonator, the coupling mechanism can also be a coupling mechanism for coupling electromagnetic energy between adjacent resonators as described above. It is evident, that in case of more than one resonator, the filter may comprise several coupling mechanisms according to the present invention, some of which are input or output coupling mechanisms and some of which provide coupling between adjacent resonators.
  • the above construction provides the advantage of a simple and reliable coupling mechanism having a large tuning range.
  • the second elongate portion terminates in a connector component to thereby form an input or output coupling mechanism.
  • the connector component can be constituted by a part of or the entire second elongate portion, or the connector component can be a component secured to the outer terminal end of the second elongate portion.
  • the connector component will advantageously be secured to and thus stationary with respect to the wall portion.
  • the connector component or the second elongate portion has a bend formed therein to allow for compensation of the movement of portions of the coupling element to avoid damaging the connection of the connector component to the wall portion.
  • the microwave filter comprises at least one coupling mechanism of the above construction which serves as a coupling mechanism between the two resonator cavities of adjacent resonators.
  • the coupling element of such a coupling mechanism projects from the through bore into both resonator cavities.
  • first elongate portion and the second elongate portion are opposing end portions of the coupling element.
  • the coupling element is an elongate member
  • the first elongate portion and the second elongate portion are portions of the elongate member.
  • the two elongate portions are sections of the same elongate member.
  • a preferred adjustment means is adapted to coil and uncoil a portion of the elongate member between the first and the second elongate portion or to displace a portion of the elongate member between the first and the second elongate portion transversely to the direction of extension of the through bore by e.g. forming a loop. In this way, the extension of the portion of the elongate member between the first and the second elongate portion in the direction of extension of the through bore is changed, and the first and the second elongate portion are thereby displaced with respect to each other.
  • the coupling element is a capacitive coupling element.
  • a capacitive coupling element could e.g. comprise a disk-shaped portion located at the outer terminal end of the first and/or the second elongate portion.
  • the coupling element is an inductive coupling element.
  • the first and/or the second elongate portion could e.g. advantageously terminate in a flexible, electrically conductive wire electrically connected to a wall portion of the resonator.
  • These flexible, electrically conductive wires can be components attached to the outer terminal end of the respective elongate portion, or they can be part of the respective elongate portion or the elongate portion itself.
  • the adjustment means is adapted to be operable to either simultaneously advance both elongate portions out of the through bore or simultaneously retract both elongate portions into the through bore, depending on the manner in which the adjustment means is operated.
  • the adjustment means is adapted to be operable to move the first elongate portion, while the second elongate portion is not moving. In the latter case, the second elongate portion is preferably fixedly secured to the wall portion or dielectric mounting.
  • the adjustment means is adapted to be operable to selectively increase and decrease the length of the coupling element from the outer terminal end of the first elongate portion along the coupling element to the outer terminal end of the second elongate portion.
  • This can e.g. be achieved by a telescoping arrangement or, as will be explained in more detail below, by increasing and decreasing the extension of a region of overlap of the first and the second elongate portion partly running side by side.
  • first and second elongate portions are both straight. This construction is particularly simple. However, for some applications, such as e.g. an application necessitating a curved through bore, it may also be advantageous if the first and second elongate portions are both at least partly curved.
  • the first elongate portion and the second elongate portion are physically separate and distinct components of the coupling element arranged such that they overlap each other along at least a part of their length and that they extend parallel to the direction of extension of the through bore.
  • the adjustment means is then adapted to be operable to shift one of these components or both components along the direction of extension of the through bore in order to increased and decreased the region of overlap.
  • the adjustment means is adapted to be operable to shift the two components in opposite directions with respect to each other.
  • the two components are toothed racks disposed laterally offset from each other with their toothings facing each other, and the coupling element further includes a pinion which is electrically conductive to effect an electrical connection between the toothed racks or may be made of or comprise dielectric material to effect capacitive coupling between the toothed racks.
  • the pinion is located between the toothed racks and engages the toothings of the two racks, such that upon rotation of the pinion the two toothed racks are displaced with respect to each other.
  • the adjustment means is adapted to be operable to effect rotation of the pinion.
  • toothed racks While in this preferred form two toothed racks are provided, it is of course also possible that only the first elongate portion is a toothed rack, and that the adjustment means is operable to effect rotation of a pinion engaging the toothing of this toothed rack, such that upon rotation of the pinion the toothed rack is displaced with respect to the second elongate portion.
  • the adjustment means is operable to effect rotation of a pinion engaging the toothing of this toothed rack, such that upon rotation of the pinion the toothed rack is displaced with respect to the second elongate portion.
  • Providing only on toothed rack may be advantageous e.g. for an input or output coupling mechanism.
  • the pinion in case the pinion has to provide for an electrical connection between the two elongate portions, the pinion may be made of conductive material or plated with conductive material, and in case the pinion has to provide for a capacitive connection between the two elongate portions, the pinion may be made of or comprise on its outside dielectric material, such as e.g. ceramic material.
  • the pinion is preferably formed as the end portion of a rod.
  • the rod extends in a bore which is formed in the dielectric mounting and which extends perpendicularly to the direction of extension of the through bore.
  • the end portion of the rod opposite the pinion is accessible from outside the filter for rotating the rod and thereby the pinion.
  • the wheel is arranged to frictionally engage the rod(s) or other elongate element(s).
  • the wheel is positioned between them. It is preferred that such wheel is made of a material with a high coefficient of friction, such as rubber material, or comprises such material on its outside surface. With such a construction, the fine tuning capabilities of the coupling mechanism may be enhanced.
  • the coupling element including a pinion and one or more toothed racks or a wheel frictionally engaging one or more rods
  • a very small coupling mechanism can be realized which efficiently utilizes the small space available within microwave filters.
  • a pinion or possibly a wheel are preferred, it is also possible to replace the pinion or wheel with a different drive mechanism or actuator, such as a piezoelectric actuator, e.g. a linear piezoelectric motor.
  • a drive mechanism or actuator preferably comprises one or more tips engaging the one or more toothed racks or rods in order to effect their movement.
  • the tips may engage the toothing of a toothed rack or they may be friction tips frictionally engaging a rod or other elongate element. There may e.g. be one tip for effecting movement in both directions, or there may e.g. be separate tips for the two directions of movement.
  • the dielectric mounting is made from PTFE (polytetrafluor ethylene), polyethylene, FEP (fluorinated ethylene-propylene) or PEEK (polyether etherketone).
  • PTFE polytetrafluor ethylene
  • FEP fluorinated ethylene-propylene
  • PEEK polyether etherketone
  • the dielectric mounting is secured in the wall portion in such a manner that it may be rotated together with the coupling element to thereby change the orientation of the first and second elongate portions of the coupling element within the resonator cavities. In this way, an additional tuning possibility is provided, thereby increasing ease of tuning and the tuning range.
  • the adjustment means is disposed entirely or partly within the wall portion, i.e. in the through bore and/or in an additional bore or cavity formed in the wall portion. Further, the adjustment means is arranged to act on the coupling element within the wall portion, such as e.g. within the through bore. In any case, the adjustment means preferably does not protrude from the wall portion into an adjacent resonator cavity. However, it might be advantageous if a part of the adjustment means protrudes to the outside of the filter to be easily accessible for operating the adjustment means.
  • a preferred microwave filter includes a plurality of coupled resonators including at least one combline resonator and/or at least one dielectric resonator, and at least one of coupling mechanism according to the present invention arranged to provide for coupling of electromagnetic energy into or out of a combline resonator and/or a dielectric resonator.
  • the microwave filter may of course comprise several coupling mechanisms according to the present invention, where the various coupling mechanisms may be identical or different in construction.
  • the coupling mechanisms could comprise different of the above-described features.
  • some of the coupling mechanisms could comprise a capacitive coupling element and some of the coupling mechanisms could comprise an inductive coupling element.
  • Figure 1 shows a perspective view of a portion of a combline resonator microwave filter 1 according to the present invention with the upper cover of the filter removed.
  • the filter 1 comprises side walls 2 and a bottom wall 3 which, together with the upper cover, define a plurality of resonator cavities 4.
  • an inner conductor 5 is disposed which is secured and electrically connected to the bottom wall 3 and extends upwardly therefrom along the central longitudinal axis of the resonator cavity 4.
  • Each resonator cavity 4 together with the corresponding inner conductor 5 and wall portions 2, 3 (and the cover) constitutes a combline resonator or combline resonant section.
  • a coupling window or coupling iris 6 is formed in the common side wall 2 separating the respective resonator cavities 4 to thereby form the main coupling path of the filter in the usual manner.
  • a further coupling mechanism 7, providing electrical coupling is disposed in the side wall 2 between two combline resonators not adjacent along the main coupling path to thereby provide for cross-coupling.
  • This coupling mechanism 7 is a coupling mechanism according to the present invention and is shown isolated in Figure 2 and in more detail in the exploded illustration shown in Figure 3.
  • the coupling mechanism 7 comprises a cylindrical dielectric mounting body 8 which has a cylindrical through bore 9 extending perpendicularly to the axis of the cylinder 8. Further, the coupling mechanism 7 comprises an electrically conductive coupling element 10 in the form of a capacitive probe, which is composed of three separate parts, namely a first electrically conductive rigid elongate portion or rod 11a having a capacitive disk 12a secured to its one end, a second electrically conductive rigid elongate portion or rod 11b having a capacitive disk 12b secured to its one end, and an electrically conductive pinion 13, which is formed on the end of a rod 14. At least the surface of pinion 13 must have good electrical conductivity.
  • the coupling element 10 is shown in the assembled state, but with the dielectric mounting body 8 removed in Figure 4.
  • Each rigid elongate portion or rod 11a, 11b is constructed as a part cylinder having a toothing 15a and 15b, respectively, formed on its flat surface along a part of its length.
  • the two rigid elongate portions or rods 11a, 11b are toothed racks.
  • the two toothed racks 11a, 11b are arranged such that their toothings 15a, 15b face each other, with the pinion 13 disposed between the toothed racks 11a, 11b in meshing engagement with both toothings 15a, 15b (see Figure 4) .
  • the through bore 9 is dimensioned to receive the toothed racks 11a, 11b and the pinion 13 in the state shown in Figure 4.
  • the dimensions of the toothed racks 11a, 11b and the pinion 13 are chosen such that there is only a small clearance between the curved outside surfaces of the toothed racks 11a, 11b and the inside surface of the through bore 9. In this way, the toothed racks 11a, 11b and the pinion 13 are secured against lateral movement. Further, because the pinion 13 is in meshing engagement with the toothings 15a, 15b, the toothed racks 11a, 11b cannot move freely in the axial direction, i.e. the direction of extension, of the through bore 9.
  • each toothed rack 11a, 11b is disposed adjacent one of the two opposing openings 16 of the through bore 9 and projects from the through bore 9 into the respective resonator cavity 4.
  • each toothed rack 11a, 11b extends partly within the through bore 9 and partly in the resonator cavity 4.
  • the capacitive disks 12a, 12b are located inside the respective resonator cavity 4.
  • the basic principle behind this embodiment as compared to prior art coupling mechanisms is that the coupling element is split up into two parts which are moveable against each other by means of a pinion located between them in the center of the coupling element to increase or decrease the length of the coupling element.
  • the cylindrical mounting body 8 further has a cut 17 which extends from one of its end faces and merges into through bore 9, and a cylindrical bore 18 which likewise extends from the same end face of the mounting body 8 along the axial direction of the mounting body 8 before merging into through bore 9.
  • the cylindrical bore 18 is dimensioned to receive the rod 14 and the pinion 13 with a small clearance to allow for rotation of the rod 14 inside the bore 18. This arrangement greatly facilitates securing the coupling element 10 in the mounting 8 without sacrificing the reliability of the connection.
  • the mounting body 8 is formed from a material, which enables elastically spreading away the two cylinder portions separated by the cut 17 to form a gap and to thereby temporarily expand the through bore 9 such that the toothed racks 11a, 11b can be inserted into the through bore 9 in their appropriate position but with a distance between the toothings 15a, 15b greater than the diameter of pinion 13. Subsequently, the rod 14 can be inserted through the cylindrical bore 18 until the pinion 13 is positioned in the center of expanded through bore 9. Then, the two spaced apart cylinder portions can be released to close the gap and to return through bore 9 to its normal dimensions. In this way, the toothings 15a, 15b are brought into meshing engagement with pinion 13 and the coupling element 10 is secured in the mounting body 8.
  • the rod 14 On the end opposite the pinion 13, the rod 14 has an enlarged diameter portion 19 with a slit 20.
  • the bore 18 in the mounting body 8 comprises a lower section and an enlarged diameter upper section, thereby forming a shoulder on which the enlarged diameter portion 19 can rest. By means of this shoulder, the axial position of the pinion 13 within through bore 9 is determined.
  • the rod 14 can be easily rotated by means of e.g. a screw driver inserted through the bore 18 and engaging slit 20 (see Figure 5).
  • Rod 14 with enlarged diameter portion 19 and slit 20 forms an adjustment means for changing the length of coupling element 10 and, thus, the coupling characteristics of the coupling mechanism 7.
  • the enlarged diameter portion 19 and the remainder of the rod 14 should have no electrical contact with the wall portions of the filter. Therefore, the enlarged diameter portion 19 should be disposed sufficiently deep inside the mounting body 8.
  • the entire rod 14 with the exception of pinion 13 could be made of dielectric material.
  • the rod 14 including the pinion 13 could be made of dielectric material, with only the pinion 13 being plated with conductive material such as e.g. silver or copper.
  • the above construction of the dielectric mounting 8 is advantageous not only in this particular embodiment, but also for all other embodiments of the present invention.
  • a coupling element that does not comprise several parts but is formed in one piece, can be easily secured by spreading away the two cylinder portions separated by the cut 17 to form a gap sufficiently large to allow a center portion of the coupling element to be slid through the cut 17 into through bore 9.
  • the dielectric mounting 8 could also be constructed differently.
  • it could comprise a lower part having a bore for the toothed racks and a bore for the pinion, and an upper part which ensures that the enlarged diameter portion 19 of rod 14 cannot move upwardly in order to provide mechanical stability and avoid contact with the wall portions of the filter.
  • the coupling mechanism 7 is secured in the side wall 2 separating the adjacent resonator cavities 4 to be coupled by fitting the mounting body 8 into an opening 21 which is cut out from the upper end of the side wall 2 (see Figure 1).
  • the opposing surfaces of the cut-out 21 in the side wall 2 are adapted to conform to the surface of the cylindrical mounting body 8 and are dimensioned to receive this cylindrical mounting body 8 in a press fitting manner. This ensures that the coupling mechanism 7 is securely held in place once the mounting 8 is in its press-fitting seat in the cut-out 21.
  • the through bore 9 of the mounting 8 extends transversely to the side wall 2 and constitutes a through bore through the side wall 2. This state is shown in Figures 4 and 5.
  • the cylindrical shape of the mounting body 8 together with the complementary cylinder segment shape of the opposing surfaces of the cut-out 21 provide for a press-fitting seat of the mounting body 8. Nevertheless, it is possible to turn the mounting body 8 inside the cut-out 21 in order to alter the orientation or direction of the coupling element 10. Since this also alters the locations of the capacitive disks 12a, 12b inside the resonator cavities 4, the capacitive coupling strength may be altered. This can also be achieved if the cover (not shown) is already closed and fixed, if an opening is provided in the cover in the area over the mounting body 8. This is also advantageous in case access to the enlarged diameter portion 19 of adjustment rod 14 without the need to remove the cover is desired.
  • a further advantage of the cylindrical mounting body 8 is that it can be received in openings which are formed in side walls of different thicknesses.
  • a side wall of greater thickness a larger part of the cylinder surface is surrounded by the opposing surfaces of the opening in the side wall, whereas in thinner side walls only a relatively small part of the cylinder surface is engaged by the opposing surfaces of the opening, whereas the radius of curvature of the opposing surfaces of the opening in the side wall is always the same and equal to the radius of the cylinder.
  • FIG. 6 shows a perspective view of a dielectric TM mode microwave filter 1' according to the present invention with a wall portion removed.
  • the dielectric resonator filter 1' comprises two resonator cavities 4 coupled by means of a coupling mechanism 7' having an inductive coupling element 10'.
  • the filter 1' comprises side walls 2, a bottom wall 3 and a cover 22 defining the resonator cavities 4.
  • a dielectric rod 23 is disposed and extends between the bottom wall 3 the cover 22.
  • Each resonator cavity 4 together with the corresponding dielectric rod 23 and wall portions 2, 3, and 22 constitutes a dielectric resonator or dielectric resonant section.
  • the coupling mechanism 7' providing magnetic coupling, is disposed in the side wall 2 between the two adjacent dielectric resonators. It is constructed identically to the coupling mechanism 7 shown in Figures 1 to 5 with the exception of the capacitive disks 12a, 12b being replaced with flexible, electrically conductive wires 24a, 24b.
  • One end of the wires 24a, 24b is secured, e.g. by soldering, to the outer terminal end of toothed racks 11a and 11b, respectively, and the other end of wires 24a, 24b is secured, e.g. by soldering or screwing, to one of the wall portions 2, 3, or 22. Due to the movement of the toothed racks 11a, 11b upon adjustment, the wires should be of sufficient flexibility and length to allow for compensation of the movement.
  • Figures 7 and 8 show a further embodiment of the present invention, in which a coupling mechanism 7" is provided as an input or output coupling mechanism to the first combline resonator or combline resonant section of a combline resonator microwave filter 1".
  • Figures 7 and 8 could also show an edge region of the combline filter 1 shown in Figures 1 to 5.
  • the combline filter 1'' comprises a side wall 2'' of increased thickness as compared to side walls 2 separating adjacent resonator cavities 4. While the construction of the filter 1'' and the arrangement of coupling mechanism 7" in the side wall 2'' is largely identical to the construction shown in Figures 1 to 5, the mounting body 8 is disposed completely inside the side wall 2'', and the through bore 9 through the mounting body 8 is not identical with the through bore through the side wall 2" . Rather, a through bore 9" is formed through the side wall 2'' which has a larger diameter than through bore 9.
  • the coupling mechanism 7" is constructed identically to the coupling mechanism 7 shown in Figures 1 to 5 with the exception of one of the toothed racks 11a, 11b being replaced with a flexible, electrically conductive wire 25 and of the other toothed rack 11b" not having a capacitive disk at its end (although a capacitive disk could be provided to increase the coupling strength).
  • a suitable stationary toothing is present inside through bore 9 of mounting body 8, and the pinion 13 is in meshing engagement with this toothing and the toothing 15b'' of toothed rack 11b".
  • the wire 25 is the inner conductor of a coaxial connector 27 and is connected, e.g. by soldering, to the end of toothed rack 11b" opposite the end projecting into the resonator cavity 4.
  • a loop or bend 26 is formed to allow for compensation of the motion of the toothed rack 11b" upon rotation of pinion 13.
  • Another possibility is to provide an inflexible inner conductor which is arranged such that it is pressed against the moving toothed rack 11b" to provide a sliding electrical contact.
  • the pinion 13 is preferably not conductive and advantageously made of nonconductive material.
  • coupling mechanism 7 provides for capacitive coupling. However, it could also be realized as inductive coupling as described above.

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Cited By (9)

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WO2010147418A2 (ko) * 2009-06-18 2010-12-23 주식회사 에이스테크놀로지 크로스 커플링 조절 장치 및 이를 포함하는 rf 캐비티 필터
EP2405531A1 (de) * 2010-07-07 2012-01-11 Powerwave Finland Oy Resonatorfilter
EP2429026A1 (de) * 2010-09-10 2012-03-14 Alcatel Lucent Filter für Funkfrequenzsignale
US9105955B2 (en) 2011-07-06 2015-08-11 Intel Corporation Adjustable resonator filter and method for adjusting coupling between resonator cavities
CN108091966A (zh) * 2017-12-07 2018-05-29 南京乾波通信技术有限公司 一种可调机械滤波器
CN108281740A (zh) * 2018-03-27 2018-07-13 深圳市华扬通信技术有限公司 带有可调电容耦合结构的腔体滤波器
EP3598568A1 (de) * 2018-07-20 2020-01-22 The Boeing Company Abstimmbare sonde für hochleistungsfähige kreuzgekoppelte hf-filter
EP3823090A1 (de) * 2018-07-13 2021-05-19 Comba Telecom Technology (Guangzhou) Limited Kapazitive kreuzkopplungsstruktur und hohlraumfilter
CN114243239A (zh) * 2021-11-30 2022-03-25 南京沁智电子科技有限公司 一种腔体滤波器及腔体滤波器的交叉耦合结构

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FR2365243A1 (fr) * 1976-09-21 1978-04-14 Nippon Electric Co Compensateur de retard pour microondes comprenant une paire d'elements a constantes reparties en tant que coupleur directionnel
US4307357A (en) * 1980-03-04 1981-12-22 Tektronix, Inc. Foreshortened coaxial resonators
US5608363A (en) * 1994-04-01 1997-03-04 Com Dev Ltd. Folded single mode dielectric resonator filter with cross couplings between non-sequential adjacent resonators and cross diagonal couplings between non-sequential contiguous resonators
US6304160B1 (en) * 1999-05-03 2001-10-16 The Boeing Company Coupling mechanism for and filter using TE011 and TE01δ mode resonators
US6317013B1 (en) * 1999-08-16 2001-11-13 K & L Microwave Incorporated Delay line filter

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FR2365243A1 (fr) * 1976-09-21 1978-04-14 Nippon Electric Co Compensateur de retard pour microondes comprenant une paire d'elements a constantes reparties en tant que coupleur directionnel
US4307357A (en) * 1980-03-04 1981-12-22 Tektronix, Inc. Foreshortened coaxial resonators
US5608363A (en) * 1994-04-01 1997-03-04 Com Dev Ltd. Folded single mode dielectric resonator filter with cross couplings between non-sequential adjacent resonators and cross diagonal couplings between non-sequential contiguous resonators
US6304160B1 (en) * 1999-05-03 2001-10-16 The Boeing Company Coupling mechanism for and filter using TE011 and TE01δ mode resonators
US6317013B1 (en) * 1999-08-16 2001-11-13 K & L Microwave Incorporated Delay line filter

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010147418A3 (ko) * 2009-06-18 2011-02-24 주식회사 에이스테크놀로지 크로스 커플링 조절 장치 및 이를 포함하는 rf 캐비티 필터
WO2010147418A2 (ko) * 2009-06-18 2010-12-23 주식회사 에이스테크놀로지 크로스 커플링 조절 장치 및 이를 포함하는 rf 캐비티 필터
CN102460825A (zh) * 2009-06-18 2012-05-16 Ace技术株式会社 交叉耦合调节装置以及包括该装置的rf腔体滤波器
CN102460825B (zh) * 2009-06-18 2014-07-23 Ace技术株式会社 交叉耦合调节装置以及包括该装置的rf腔体滤波器
US8847709B2 (en) 2010-07-07 2014-09-30 Powerwave Technologies S.A.R.L. Resonator filter
EP2405531A1 (de) * 2010-07-07 2012-01-11 Powerwave Finland Oy Resonatorfilter
EP2429026A1 (de) * 2010-09-10 2012-03-14 Alcatel Lucent Filter für Funkfrequenzsignale
US9105955B2 (en) 2011-07-06 2015-08-11 Intel Corporation Adjustable resonator filter and method for adjusting coupling between resonator cavities
CN108091966A (zh) * 2017-12-07 2018-05-29 南京乾波通信技术有限公司 一种可调机械滤波器
CN108281740A (zh) * 2018-03-27 2018-07-13 深圳市华扬通信技术有限公司 带有可调电容耦合结构的腔体滤波器
EP3823090A1 (de) * 2018-07-13 2021-05-19 Comba Telecom Technology (Guangzhou) Limited Kapazitive kreuzkopplungsstruktur und hohlraumfilter
EP3823090A4 (de) * 2018-07-13 2022-04-20 Comba Telecom Technology (Guangzhou) Limited Kapazitive kreuzkopplungsstruktur und hohlraumfilter
EP3598568A1 (de) * 2018-07-20 2020-01-22 The Boeing Company Abstimmbare sonde für hochleistungsfähige kreuzgekoppelte hf-filter
US10985435B2 (en) 2018-07-20 2021-04-20 The Boeing Company Tunable probe for high-performance cross-coupled RF filters
CN114243239A (zh) * 2021-11-30 2022-03-25 南京沁智电子科技有限公司 一种腔体滤波器及腔体滤波器的交叉耦合结构

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