EP0197653A2 - Microwave bandpass filter including dielectric resonators - Google Patents
Microwave bandpass filter including dielectric resonators Download PDFInfo
- Publication number
- EP0197653A2 EP0197653A2 EP86301617A EP86301617A EP0197653A2 EP 0197653 A2 EP0197653 A2 EP 0197653A2 EP 86301617 A EP86301617 A EP 86301617A EP 86301617 A EP86301617 A EP 86301617A EP 0197653 A2 EP0197653 A2 EP 0197653A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- filter
- board
- coupling
- waveguide
- resonators
- 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
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
- H01P1/219—Evanescent mode filters
-
- 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
- H01P1/2084—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure with dielectric resonators
Definitions
- This invention relates to microwave bandpass filters including dielectric resonators.
- a microwave bandpass filter in the form of an iris coupled filter which comprises a waveguide, sized for propagating microwaves in the desired pass band, which is divided into a plurality of resonant chambers by partitions across the waveguide, each partition having an aperture or iris which provides for coupling microwaves into or out of the chamber.
- an n-pole filter (n being an integer) generally needs a total of 2n+1 coupling and tuning adjustments.
- a 3-pole iris coupled filter for example, these can be readily constituted by 3 tuning screws, one for each of the 3 resonant chambers of the filter, and 4 coupling screws, one for each aperture or iris.
- the iris coupled filter has the disadvantage of being of a relatively large size for microwave frequencies below about 10GHz. .
- the dielectric resonator microwave bandpass filter has a relatively smaller size due to its use of a cut-off waveguide, but known forms of this do not-facilitate providing the desired number of adjustments for achieving particular characteristics.
- Such microwave bandpass filters are typically used as channel filters in a multi-channel microwave radio transmitter.
- each filter is typically connected between the output of a modulator and the input-of a transmitting amplifier, and serves to pass only one of the two sidebands of the modulated signal for transmission.
- Connection to an iris coupled filter is conveniently effected by coaxial cable via an isoadapter, which is a combined isolator and waveguide/coaxial cable adapter, but this adds further to the large size of the filter.
- Coupling to a dielectric resonator filter can be effected in the same manner with the same disadvantage of large size, or can be effected by coaxial cable with the disadvantage of requiring an isolator to be separately provided.
- Microwave bandpass filters are also used as branching (channel combining and channel dropping) filters in microwave radio transmission systems.
- each filter conveniently has a coaxial connection at one port for coupling to a transmitting or receiving amplifier, and a waveguide coupling at the other port for connection to a circulator and thence to a transmitting or receiving antenna.
- An object of this invention is to provide an improved microwave bandpass filter.
- a microwave bandpass filter comprising: a waveguide of rectangular cross section having conductive upper, lower, and side walls; an insulating board in the waveguide having upper and lower surfaces substantially parallel to and spaced from the upper and lower walls, the lower and side walls defining a well beneath the board and supporting the board around substantially its entire periphery; a plurality of dielectric resonators supported by the board and spaced along the waveguide; a plurality of tuning screws each extending through the lower wall into the well beneath a respective one of the dielectric resonators; and means for coupling microwave signals to and from the resonators.
- the board preferably includes on its lower surface a ground plane conductor in regions where the board is supported, the ground plane being soldered to the walls to fix the board in position, and the dielectric resonators are preferably supported above the board.
- Electrically conductive spurious mode suppressors preferably extend from the lower wall through the board substantially perpendicularly thereto each between two adjacent resonators.
- coupling adjustment screws advantageously extend through a side wall of the waveguide above the board each between two adjacent resonators for varying the coupling therebetween. For example, there may be three resonators and two such coupling adjustment screws.
- each means for coupling microwave signals to or from a resonator comprises a coupling conductor on the board extending adjacent to the periphery of the resonator, each coupling conductor conveniently being on the upper surface of the board and having an unconnected end adjacent to a side wall of the waveguide.
- coupling adjustment screws preferably also extend through the side wall above the board each adjacent to the unconnected end of a respective coupling conductor for varying the coupling between this conductor and the respective resonator.
- the filter preferably also includes within the waveguide at least one isolator having a port coupled to a respective means for coupling microwave signals to or from a resonator.
- each respective means for coupling microwave signals to or from a resonator which is coupled to an isolator port comprises a microstrip transmission line, comprising a conductor and a ground plane on opposite surfaces of the board, having a characteristic impedance matched to that of the isolator. In this manner impedance matching and a compact isolator and filter arrangement are readily achieved.
- the waveguide For coupling coaxial cables to the filter and isolator arrangement, preferably there are two isolators and the waveguide includes two end walls each including a respective coaxial connector having a central connection extending through the end wall and coupled to a second port of a respective isolator.
- the waveguide conveniently comprises a body constituting the lower and side walls and a flat lid constituting the upper wall, and means for securing the lid to the body.
- the filter illustrated therein comprises a metal enclosure, forming a cut-off waveguide, formed by an elongate body 10 and a flat lid 12 which is shown only in Fig. 2.
- the body 10 is for example formed by investment casting, and subsequent machining where necessary, from an alloy comprising 83% copper, 7% lead, 7% tin, and 3% zinc.
- the body 10 has a top flange 14 along the length of each side, in which are formed a plurality of threaded holes 16 into which are screwed screws (not shown) which pass through corresponding holes (not shown) in the lid 12 to secure the lid to the body 10.
- the top flange 14 is illustrated as being cut-away in parts to show details beneath it.
- the body 10 includes an elongate cavity 18 which is described in detail below.
- the body 10 includes a continuous groove 20 in which a continuous wire mesh filament (not shown) is secured to provide an electro-magnetic seal between the body 10 and the lid 12.
- the body 10 also has at each end a flange 22 which is shaped as is best shown in Fig. 3 to form feet 24 on which the filter stands in use, so that a lower surface of the base 26 of the body 10 is supported above the surface on which the filter stands, in order to facilitate adjustment of tuning screws described below.
- the filter in this embodiment of the invention is intended to be connected between two coaxial cables, to which end a coaxial cable connector 28 is mounted externally on each end flange 22, a central pin of each connector 28 passing through an aperture in the end flange 22, as shown by broken lines in Figs. 1 and 2, to the end of the cavity 18 where it is electrically connected to one port of a respective one of two isolators 30.
- each isolator is a known form of so-called drop-in isolator which comprises a metallized ferrite substrate 32 and a cylindrical permanent magnet 34 supported therefrom.
- the ferrite substrate 32 is supported by and has on its underside a ground plane which is soldered to the base 26 of the body 10, through which there is provided a cylindrical aperture 36 to accommodate and provide access to the permanent magnet 34.
- Each aperture 36 has a counter-bore 38 at the lower surface of the base 26 to accommodate a metal cap (not shown) for electro-magnetically sealing this aperture.
- a printed circuit board 40 preferably of polyetherimide material, such as that marketed by the General Electric Company under the trade name "Ultem”, which is physically and thermally stable.
- polyetherimide material such as that marketed by the General Electric Company under the trade name "Ultem”
- PTFE which is commonly used for printed circuit boards
- the board 40 is relatively thick compared with, for example, the substrates 32.
- the upper surface of the base 26 of the body 10 is stepped, at the point where each substrate 32 and the board 40 meet, so that their upper surfaces are in the same plane.
- the coaxial cable connectors 28 are positioned so that their central pins are also in this same plane, so that electrical connections to..the ports of the isolators are readily achieved by solder bridges between the abutting contacts.
- a well 42 is formed in the base 26 of the body 10 beneath the board 40.
- the board 40 is supported at its ends, beyond the ends of the well 42, by the base 26 as shown in Fig. 2, and is supported along the lengths of its sides, beyond the sides of the well 42, by stepped sides of the base 26 as shown in Fig. 3.
- the board 40 has on its lower surface a ground plane which is soldered to the base 26 to secure the board 40 in place. The ground plane does not extend into the region of the well 42.
- dielectric resonators 44 are glued to the upper surface of the board 40 to form in this case a 3-pole bandpass filter.
- the form and selection of dielectric resonators to form bandpass filters is generally known and need not be described here. It is noted, however, that the dielectric resonators 44 are positioned above the region of the well 42, so that there is no ground plane close to the resonators. The distance between the resonators and the nearest ground plane, which is greatly increased by the provision of the well 42, maintains the high quality factor of the dielectric resonators and considerably facilitates tuning of the resonators over a relatively wide frequency range as is described further below.
- conductive tracks 46 are provided on the upper surface of the board 40.
- Each track 46 comprises. a coupling loop 48 which extends part of the way around the periphery of the respective resonator 44, a relatively wide track 50 which extends above the ground plane on the lower surface of the board 40 and forms a microstrip transmission line, and a tapered portion which couples the microstrip transmission line to the coupling loop.
- Each track 50 has a width which is selected to provide a 50 ohm characteristic impedance to match the characteristic impedance, also 50 ohms, of the isolator 30 and coaxial cable to be connected to the connector 28.
- Each track 50 is electrically connected to a second port of the respective isolator 30; a third port of each isolator 30 is terminated with a resistance of 50 ohms within the isolator itself.
- each coupling loop 48 is arranged so that its unconnected end 52 is at one side of the dielectric resonator, as shown in Fig. 1.
- a respective screw 54 extends through a threaded hole in the side wall 56 of the body 10 above the board 40 into proximity with each end 52 and the associated resonator 44, and serves for adjusting the coupling of the loop 48 to the resonator 44. Turning the screw 54 to be closer to the resonator 44 increases the coupling by increasing the fringing capacitance associated with the loop end 52.
- a locking nut 58 on each screw 54 enables the screw to be fixed in position after it has been appropriately adjusted.
- each bar 60 extends from a respective recess in the base 26 of the body 10, to which it is thereby electrically connected, upwardly through an aperture in the board 40 positioned mid-way between the dielectric resonators 44 on each side of it, to the vicinity of the lid 12.
- the bars 60 serve to suppress the propagation of spurious modes of microwave signals through the filter in a manner known for example from Nishikawa et al. U.S. Patent No. 4,138,652 issued February 6, 1979.
- Two screws 62 extend through threaded holes in the side wall 56 of the body 10 above the board 40, one opposite each of the bars 60, and enable adjustment of the coupling which is achieved between adjacent pairs of the resonators 44.
- Lock nuts 64 on these screws 62 enable them to be fixed in position after they have been appropriately adjusted to achieve desired degrees of coupling.
- each dielectric resonator 44 centrally beneath each dielectric resonator 44 there is a tuning adjustment screw 66 which extends through a respective threaded hole in the base 26 of the body 10 into the well 42 below the board 40 to permit tuning of the resonators 44.
- a respective locking nut 68 on each of the three screws 66 enables the screw to be fixed in position after tuning.
- the bandpass filter described above provides numerous advantages and conveniences over known filters. For example, it has a relatively small size due to the use of dielectric resonators and a cut-off waveguide, and the incorporation of the isolators 30 within the body 10.
- the use of the flat lid 12 is a convenience in manufacture, and because this lid 12 does not incorporate any adjusting screws it can be removed and replaced without disturbing tuning and coupling adjustments.
- the provision of the well 42 increases the distances between the resonators 44 and ground planes, thereby maintaining the high quality factor of the dielectric resonators and facilitating adjustment of the filter for particular characteristics within relatively wide ranges.
- the positioning of the tuning screws 66 below the board 40 and below the resonators 44, and the coupling adjustment screws 54 and 62 above the board 40 and at one side of the resonators 44 provides a substantial degree of independence of the tuning and coupling adjustments, so that the coupling and tuning adjustments do not mutually and adversely affect one another to a large extent. It should be noted that the 4 coupling adjustment screws and the 3 tuning screws provided the desired total of 7 adjustments for the described 3-pole filter.
- the above description relates to a filter incorporating isolators and for coupling between two coaxial cables, it should be appreciated that at one or both ends of the filter the isolator could, if desired, be omitted, and/or coupling may be effected in known manner to a waveguide rather than to a coaxial cable connector. It should also be appreciated that the microstrip connector formed by the track 50 may be modified or replaced by other suitable forms of coupling.
Abstract
Description
- This invention relates to microwave bandpass filters including dielectric resonators.
- It is known for example from Nishikawa et al. U.S. Patent No. 4,143,344 issued March 6, 1979 to provide a microwave bandpass filter which is constituted by a cut-off waveguide, i.e. a waveguide whose size is too small to propagate microwaves in a desired range of frequencies, in which there are disposed a plurality of tuned dielectric resonators to provide coupling of microwaves in the desired pass band from an input coupler to an output coupler.
- It is also known to provide a microwave bandpass filter in the form of an iris coupled filter which comprises a waveguide, sized for propagating microwaves in the desired pass band, which is divided into a plurality of resonant chambers by partitions across the waveguide, each partition having an aperture or iris which provides for coupling microwaves into or out of the chamber.
- In order to provide a desired bandpass filter characteristic it has been determined that an n-pole filter (n being an integer) generally needs a total of 2n+1 coupling and tuning adjustments. For a 3-pole iris coupled filter, for example, these can be readily constituted by 3 tuning screws, one for each of the 3 resonant chambers of the filter, and 4 coupling screws, one for each aperture or iris. However, the iris coupled filter has the disadvantage of being of a relatively large size for microwave frequencies below about 10GHz. .
- In contrast, the dielectric resonator microwave bandpass filter has a relatively smaller size due to its use of a cut-off waveguide, but known forms of this do not-facilitate providing the desired number of adjustments for achieving particular characteristics.
- Such microwave bandpass filters are typically used as channel filters in a multi-channel microwave radio transmitter. In such an application, each filter is typically connected between the output of a modulator and the input-of a transmitting amplifier, and serves to pass only one of the two sidebands of the modulated signal for transmission. Connection to an iris coupled filter is conveniently effected by coaxial cable via an isoadapter, which is a combined isolator and waveguide/coaxial cable adapter, but this adds further to the large size of the filter. Coupling to a dielectric resonator filter can be effected in the same manner with the same disadvantage of large size, or can be effected by coaxial cable with the disadvantage of requiring an isolator to be separately provided.
- Microwave bandpass filters are also used as branching (channel combining and channel dropping) filters in microwave radio transmission systems. In such a case each filter conveniently has a coaxial connection at one port for coupling to a transmitting or receiving amplifier, and a waveguide coupling at the other port for connection to a circulator and thence to a transmitting or receiving antenna.
- An object of this invention, therefore, is to provide an improved microwave bandpass filter.
- According to this invention there is provided a microwave bandpass filter comprising: a waveguide of rectangular cross section having conductive upper, lower, and side walls; an insulating board in the waveguide having upper and lower surfaces substantially parallel to and spaced from the upper and lower walls, the lower and side walls defining a well beneath the board and supporting the board around substantially its entire periphery; a plurality of dielectric resonators supported by the board and spaced along the waveguide; a plurality of tuning screws each extending through the lower wall into the well beneath a respective one of the dielectric resonators; and means for coupling microwave signals to and from the resonators.
- The board preferably includes on its lower surface a ground plane conductor in regions where the board is supported, the ground plane being soldered to the walls to fix the board in position, and the dielectric resonators are preferably supported above the board. Electrically conductive spurious mode suppressors preferably extend from the lower wall through the board substantially perpendicularly thereto each between two adjacent resonators. In addition, coupling adjustment screws advantageously extend through a side wall of the waveguide above the board each between two adjacent resonators for varying the coupling therebetween. For example, there may be three resonators and two such coupling adjustment screws.
- Preferably each means for coupling microwave signals to or from a resonator comprises a coupling conductor on the board extending adjacent to the periphery of the resonator, each coupling conductor conveniently being on the upper surface of the board and having an unconnected end adjacent to a side wall of the waveguide. In this case coupling adjustment screws preferably also extend through the side wall above the board each adjacent to the unconnected end of a respective coupling conductor for varying the coupling between this conductor and the respective resonator.
- The filter preferably also includes within the waveguide at least one isolator having a port coupled to a respective means for coupling microwave signals to or from a resonator. Conveniently each respective means for coupling microwave signals to or from a resonator which is coupled to an isolator port comprises a microstrip transmission line, comprising a conductor and a ground plane on opposite surfaces of the board, having a characteristic impedance matched to that of the isolator. In this manner impedance matching and a compact isolator and filter arrangement are readily achieved.
- For coupling coaxial cables to the filter and isolator arrangement, preferably there are two isolators and the waveguide includes two end walls each including a respective coaxial connector having a central connection extending through the end wall and coupled to a second port of a respective isolator.
- The waveguide conveniently comprises a body constituting the lower and side walls and a flat lid constituting the upper wall, and means for securing the lid to the body.
- The invention will be further understood from the following description with reference to the accompanying drawings, in which:
- Fig. 1 is a partly cut-away plan view of a dielectric resonator microwave bandpass filter, with a lid thereof removed, in accordance with an embodiment of the invention;
- Fig. 2 is a longitudinal sectional illustration of the filter of Fig. 1, the section being taken on the lines II-II in Fig. 1; and
- Fig. 3 is a cross sectional illustration of the filter, the section being taken on the lines III-III in Fig. 2.
- Referring to the drawings, the filter illustrated therein comprises a metal enclosure, forming a cut-off waveguide, formed by an
elongate body 10 and a flat lid 12 which is shown only in Fig. 2. Thebody 10 is for example formed by investment casting, and subsequent machining where necessary, from an alloy comprising 83% copper, 7% lead, 7% tin, and 3% zinc. Thebody 10 has atop flange 14 along the length of each side, in which are formed a plurality of threadedholes 16 into which are screwed screws (not shown) which pass through corresponding holes (not shown) in the lid 12 to secure the lid to thebody 10. In Fig. 1 thetop flange 14 is illustrated as being cut-away in parts to show details beneath it. - The
body 10 includes anelongate cavity 18 which is described in detail below. In thetop flange 14 and immediately surrounding the entire periphery of thecavity 18 thebody 10 includes acontinuous groove 20 in which a continuous wire mesh filament (not shown) is secured to provide an electro-magnetic seal between thebody 10 and the lid 12. - The
body 10 also has at each end aflange 22 which is shaped as is best shown in Fig. 3 to formfeet 24 on which the filter stands in use, so that a lower surface of thebase 26 of thebody 10 is supported above the surface on which the filter stands, in order to facilitate adjustment of tuning screws described below. - The filter in this embodiment of the invention is intended to be connected between two coaxial cables, to which end a
coaxial cable connector 28 is mounted externally on eachend flange 22, a central pin of eachconnector 28 passing through an aperture in theend flange 22, as shown by broken lines in Figs. 1 and 2, to the end of thecavity 18 where it is electrically connected to one port of a respective one of twoisolators 30. As is best shown in Fig. 2, each isolator is a known form of so-called drop-in isolator which comprises ametallized ferrite substrate 32 and a cylindricalpermanent magnet 34 supported therefrom. Theferrite substrate 32 is supported by and has on its underside a ground plane which is soldered to thebase 26 of thebody 10, through which there is provided acylindrical aperture 36 to accommodate and provide access to thepermanent magnet 34. Eachaperture 36 has acounter-bore 38 at the lower surface of thebase 26 to accommodate a metal cap (not shown) for electro-magnetically sealing this aperture. - Between the
isolators 30 there extends a printedcircuit board 40 preferably of polyetherimide material, such as that marketed by the General Electric Company under the trade name "Ultem", which is physically and thermally stable. In this respect it is observed that other materials could be used, but PTFE, which is commonly used for printed circuit boards, is preferably not used because it has a discontinuity in its expansion-temperature characteristic at a temperature of about 25°C and hence lacks thermal stability. For physical stability theboard 40 is relatively thick compared with, for example, thesubstrates 32. In consequence, the upper surface of thebase 26 of thebody 10 is stepped, at the point where eachsubstrate 32 and theboard 40 meet, so that their upper surfaces are in the same plane. Thecoaxial cable connectors 28 are positioned so that their central pins are also in this same plane, so that electrical connections to..the ports of the isolators are readily achieved by solder bridges between the abutting contacts. - As indicated by a broken line in Fig. 1, a
well 42 is formed in thebase 26 of thebody 10 beneath theboard 40. Theboard 40 is supported at its ends, beyond the ends of thewell 42, by thebase 26 as shown in Fig. 2, and is supported along the lengths of its sides, beyond the sides of thewell 42, by stepped sides of thebase 26 as shown in Fig. 3. In these support regions theboard 40 has on its lower surface a ground plane which is soldered to thebase 26 to secure theboard 40 in place. The ground plane does not extend into the region of thewell 42. - Three
dielectric resonators 44 are glued to the upper surface of theboard 40 to form in this case a 3-pole bandpass filter. The form and selection of dielectric resonators to form bandpass filters is generally known and need not be described here. It is noted, however, that thedielectric resonators 44 are positioned above the region of thewell 42, so that there is no ground plane close to the resonators. The distance between the resonators and the nearest ground plane, which is greatly increased by the provision of thewell 42, maintains the high quality factor of the dielectric resonators and considerably facilitates tuning of the resonators over a relatively wide frequency range as is described further below. - For coupling microwave frequency signals between each of the
isolators 30 and the respectivedielectric resonator 44 which is nearest to it,conductive tracks 46 are provided on the upper surface of theboard 40. Eachtrack 46 comprises. acoupling loop 48 which extends part of the way around the periphery of therespective resonator 44, a relativelywide track 50 which extends above the ground plane on the lower surface of theboard 40 and forms a microstrip transmission line, and a tapered portion which couples the microstrip transmission line to the coupling loop. Eachtrack 50 has a width which is selected to provide a 50 ohm characteristic impedance to match the characteristic impedance, also 50 ohms, of theisolator 30 and coaxial cable to be connected to theconnector 28. Eachtrack 50 is electrically connected to a second port of therespective isolator 30; a third port of eachisolator 30 is terminated with a resistance of 50 ohms within the isolator itself. - The width of the track forming each coupling loop, its spacing from the periphery of the
dielectric resonator 44 to which it couples, the angle which this loop subtends at the axis of this resonator, and the distance of the loop (and hence the resonator) from the edge of thewell 42 are all selected to optimize the matching and coupling between the microstrip connector and the resonator, for the desired pass band of the bandpass filter. In any event, eachcoupling loop 48 is arranged so that itsunconnected end 52 is at one side of the dielectric resonator, as shown in Fig. 1. Arespective screw 54 extends through a threaded hole in theside wall 56 of thebody 10 above theboard 40 into proximity with eachend 52 and the associatedresonator 44, and serves for adjusting the coupling of theloop 48 to theresonator 44. Turning thescrew 54 to be closer to theresonator 44 increases the coupling by increasing the fringing capacitance associated with theloop end 52. Alocking nut 58 on eachscrew 54 enables the screw to be fixed in position after it has been appropriately adjusted. - Between the central one of the three
dielectric resonators 44 and each outer one of theseresonators 44 there is provided an electrically conductiveupright bar 60 which constitutes a spurious mode suppressor. As is best shown in Fig. 2, eachbar 60 extends from a respective recess in thebase 26 of thebody 10, to which it is thereby electrically connected, upwardly through an aperture in theboard 40 positioned mid-way between thedielectric resonators 44 on each side of it, to the vicinity of the lid 12. Thebars 60 serve to suppress the propagation of spurious modes of microwave signals through the filter in a manner known for example from Nishikawa et al. U.S. Patent No. 4,138,652 issued February 6, 1979. - Two
screws 62 extend through threaded holes in theside wall 56 of thebody 10 above theboard 40, one opposite each of thebars 60, and enable adjustment of the coupling which is achieved between adjacent pairs of theresonators 44. Lock nuts 64 on thesescrews 62 enable them to be fixed in position after they have been appropriately adjusted to achieve desired degrees of coupling. - As shown in Figs. 2 and 3, centrally beneath each
dielectric resonator 44 there is atuning adjustment screw 66 which extends through a respective threaded hole in thebase 26 of thebody 10 into the well 42 below theboard 40 to permit tuning of theresonators 44. Arespective locking nut 68 on each of the threescrews 66 enables the screw to be fixed in position after tuning. - The bandpass filter described above provides numerous advantages and conveniences over known filters. For example, it has a relatively small size due to the use of dielectric resonators and a cut-off waveguide, and the incorporation of the
isolators 30 within thebody 10. The use of the flat lid 12 is a convenience in manufacture, and because this lid 12 does not incorporate any adjusting screws it can be removed and replaced without disturbing tuning and coupling adjustments. - The provision of the well 42 increases the distances between the
resonators 44 and ground planes, thereby maintaining the high quality factor of the dielectric resonators and facilitating adjustment of the filter for particular characteristics within relatively wide ranges. The positioning of the tuning screws 66 below theboard 40 and below theresonators 44, and the coupling adjustment screws 54 and 62 above theboard 40 and at one side of theresonators 44, provides a substantial degree of independence of the tuning and coupling adjustments, so that the coupling and tuning adjustments do not mutually and adversely affect one another to a large extent. It should be noted that the 4 coupling adjustment screws and the 3 tuning screws provided the desired total of 7 adjustments for the described 3-pole filter. - Although the above description relates to a filter incorporating isolators and for coupling between two coaxial cables, it should be appreciated that at one or both ends of the filter the isolator could, if desired, be omitted, and/or coupling may be effected in known manner to a waveguide rather than to a coaxial cable connector. It should also be appreciated that the microstrip connector formed by the
track 50 may be modified or replaced by other suitable forms of coupling. - These and numerous other modifications, variations, and adaptations may be made to the particular bandpass filter described above without departing from the scope of the invention, which is defined by the claims.
Claims (18)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT86301617T ATE69671T1 (en) | 1985-04-03 | 1986-03-06 | MICROWAVE BANDPASS FILTERS WITH DIELECTRIC RESONATORS. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA478332 | 1985-04-03 | ||
CA000478332A CA1229389A (en) | 1985-04-03 | 1985-04-03 | Microwave bandpass filters including dielectric resonators |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0197653A2 true EP0197653A2 (en) | 1986-10-15 |
EP0197653A3 EP0197653A3 (en) | 1988-06-22 |
EP0197653B1 EP0197653B1 (en) | 1991-11-21 |
Family
ID=4130192
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86301617A Expired - Lifetime EP0197653B1 (en) | 1985-04-03 | 1986-03-06 | Microwave bandpass filter including dielectric resonators |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0197653B1 (en) |
JP (2) | JPS61230501A (en) |
AT (1) | ATE69671T1 (en) |
AU (1) | AU575469B2 (en) |
CA (1) | CA1229389A (en) |
DE (1) | DE3682523D1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0235123A1 (en) * | 1985-07-08 | 1987-09-09 | Ford Aerospace & Communication | Narrow bandpass dielectric resonator filter. |
GB2263363A (en) * | 1992-01-07 | 1993-07-21 | Marconi Gec Ltd | Electrical filter. |
WO1998028813A2 (en) * | 1996-12-20 | 1998-07-02 | Telefonaktiebolaget Lm Ericsson (Publ) | Fixed tuneable loop |
EP1079457A2 (en) * | 1999-08-24 | 2001-02-28 | Murata Manufacturing Co., Ltd. | Dielectric resonance device, dielectric filter, composite dielectric filter device, dielectric duplexer, and communication apparatus |
DE10348909A1 (en) * | 2003-10-21 | 2005-06-02 | Siemens Ag | Filter element for filtering electromagnetic waves, especially bandpass filter or band blocking filter, has resonator held at distance from contacting structure in recess in circuit board by suitable attachment arrangement |
WO2007005580A1 (en) * | 2005-06-30 | 2007-01-11 | Intermec Ip Corp. | Apparatus and method to facilitate wireless communications of automatic data collection devices in potentially hazardous environments |
US7453336B2 (en) | 2003-10-21 | 2008-11-18 | Siemens Aktiengesellschaft | Coupling structure for cylindrical resonators |
EP2919317A4 (en) * | 2012-12-10 | 2015-12-02 | Zte Corp | Dielectric resonator, assembly method therefor, and dielectric filter |
WO2023138088A1 (en) * | 2022-01-21 | 2023-07-27 | Telefonaktiebolaget Lm Ericsson (Publ) | Isolation-filtering unit |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6221301A (en) * | 1985-07-22 | 1987-01-29 | Nec Corp | Dielectric resonator filter |
JPH03121703U (en) * | 1990-03-27 | 1991-12-12 | ||
JPH03128304U (en) * | 1990-04-02 | 1991-12-24 | ||
JPH04347909A (en) * | 1991-05-24 | 1992-12-03 | Nec Corp | Dielectric resonator filter |
JP2800890B2 (en) * | 1996-09-27 | 1998-09-21 | 日本電気株式会社 | Microwave circuit |
CN101978551A (en) * | 2007-12-13 | 2011-02-16 | 天瑞通讯产品有限公司 | A microwave filter |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3798578A (en) * | 1970-11-26 | 1974-03-19 | Japan Broadcasting Corp | Temperature compensated frequency stabilized composite dielectric resonator |
JPS51139745A (en) * | 1975-05-28 | 1976-12-02 | Oki Electric Ind Co Ltd | Filter |
JPS5372438A (en) * | 1976-12-09 | 1978-06-27 | Toshiba Corp | Microwave circuit unit using dielectric resonator |
JPS58215101A (en) * | 1982-06-08 | 1983-12-14 | Tdk Corp | Dielectric filter |
US4477785A (en) * | 1981-12-02 | 1984-10-16 | Communications Satellite Corporation | Generalized dielectric resonator filter |
US4686496A (en) * | 1985-04-08 | 1987-08-11 | Northern Telecom Limited | Microwave bandpass filters including dielectric resonators mounted on a suspended substrate board |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5176948A (en) * | 1974-12-27 | 1976-07-03 | Kokusai Denshin Denwa Co Ltd | JUDENTAI KYOSHINKIOMOCHIITATAIIKITSUKAROHAKI |
JPS5585101A (en) * | 1978-12-22 | 1980-06-26 | Nec Corp | Dielectric substance drop-in filter |
JPS6179301A (en) * | 1984-09-27 | 1986-04-22 | Nec Corp | Band-pass filter of dielectric resonator |
-
1985
- 1985-04-03 CA CA000478332A patent/CA1229389A/en not_active Expired
-
1986
- 1986-03-06 AT AT86301617T patent/ATE69671T1/en not_active IP Right Cessation
- 1986-03-06 DE DE8686301617T patent/DE3682523D1/en not_active Expired - Fee Related
- 1986-03-06 EP EP86301617A patent/EP0197653B1/en not_active Expired - Lifetime
- 1986-03-14 AU AU54848/86A patent/AU575469B2/en not_active Ceased
- 1986-04-01 JP JP61072628A patent/JPS61230501A/en active Pending
-
1994
- 1994-05-16 JP JP006527U patent/JPH0733001U/en active Pending
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3798578A (en) * | 1970-11-26 | 1974-03-19 | Japan Broadcasting Corp | Temperature compensated frequency stabilized composite dielectric resonator |
JPS51139745A (en) * | 1975-05-28 | 1976-12-02 | Oki Electric Ind Co Ltd | Filter |
JPS5372438A (en) * | 1976-12-09 | 1978-06-27 | Toshiba Corp | Microwave circuit unit using dielectric resonator |
US4477785A (en) * | 1981-12-02 | 1984-10-16 | Communications Satellite Corporation | Generalized dielectric resonator filter |
JPS58215101A (en) * | 1982-06-08 | 1983-12-14 | Tdk Corp | Dielectric filter |
US4686496A (en) * | 1985-04-08 | 1987-08-11 | Northern Telecom Limited | Microwave bandpass filters including dielectric resonators mounted on a suspended substrate board |
Non-Patent Citations (6)
Title |
---|
1977 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, San Diego, 21st-23rd June 1977, pages 290-293, IEEE, Piscataway, US; J.K. PLOURDE et al.: "Microwave dielectric resonator filters utilizing Ba2Ti9O20 ceramics" * |
1982 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, Dallas, 15th-17th June 1982, pages 389-391, IEEE, Piscataway, US; C.L. REN: "Mode suppressor for dielectric resonator filters" * |
1982 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, Dallas, 15th-17th June 1982, pages 416-418, IEEE, Piscataway, US; M.L. MAJEWSKI et al.: "MIC directional filters using dielectric resonators" * |
PATENT ABSTRACTS OF JAPAN, vol. 1, no. 42, 25th April 1977, page 2624 E 76; & JP-A-51 139 745 (OKI DENKI KOHGYO K.K.) 02-12-1976 * |
PATENT ABSTRACTS OF JAPAN, vol. 2, no. 106, 31st August 1978, page 5659 E 78; & JP-A-53 72 438 (TOKYO SHIBAURA DENKI K.K.) 27-06-1978 * |
PATENT ABSTRACTS OF JAPAN, vol. 8, no. 66 (E-234)[1503], 28th March 1984; & JP-A-58 215 101 (TDK K.K.) 14-12-1983 * |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0235123A1 (en) * | 1985-07-08 | 1987-09-09 | Ford Aerospace & Communication | Narrow bandpass dielectric resonator filter. |
EP0235123A4 (en) * | 1985-07-08 | 1987-10-27 | Ford Aerospace & Communication | Narrow bandpass dielectric resonator filter. |
GB2263363A (en) * | 1992-01-07 | 1993-07-21 | Marconi Gec Ltd | Electrical filter. |
GB2263363B (en) * | 1992-01-07 | 1996-05-08 | Marconi Gec Ltd | Electrical filter |
WO1998028813A2 (en) * | 1996-12-20 | 1998-07-02 | Telefonaktiebolaget Lm Ericsson (Publ) | Fixed tuneable loop |
WO1998028813A3 (en) * | 1996-12-20 | 1998-09-11 | Ericsson Telefon Ab L M | Fixed tuneable loop |
US6005452A (en) * | 1996-12-20 | 1999-12-21 | Telefonaktiebolget Lm Ericsson | Fixed tuneable loop |
EP1079457A3 (en) * | 1999-08-24 | 2002-07-24 | Murata Manufacturing Co., Ltd. | Dielectric resonance device, dielectric filter, composite dielectric filter device, dielectric duplexer, and communication apparatus |
EP1079457A2 (en) * | 1999-08-24 | 2001-02-28 | Murata Manufacturing Co., Ltd. | Dielectric resonance device, dielectric filter, composite dielectric filter device, dielectric duplexer, and communication apparatus |
US6529094B1 (en) | 1999-08-24 | 2003-03-04 | Murata Manufacturing Co. Ltd. | Dielectric resonance device, dielectric filter, composite dielectric filter device, dielectric duplexer, and communication apparatus |
DE10348909A1 (en) * | 2003-10-21 | 2005-06-02 | Siemens Ag | Filter element for filtering electromagnetic waves, especially bandpass filter or band blocking filter, has resonator held at distance from contacting structure in recess in circuit board by suitable attachment arrangement |
US7453336B2 (en) | 2003-10-21 | 2008-11-18 | Siemens Aktiengesellschaft | Coupling structure for cylindrical resonators |
WO2007005580A1 (en) * | 2005-06-30 | 2007-01-11 | Intermec Ip Corp. | Apparatus and method to facilitate wireless communications of automatic data collection devices in potentially hazardous environments |
US7271679B2 (en) | 2005-06-30 | 2007-09-18 | Intermec Ip Corp. | Apparatus and method to facilitate wireless communications of automatic data collection devices in potentially hazardous environments |
EP2919317A4 (en) * | 2012-12-10 | 2015-12-02 | Zte Corp | Dielectric resonator, assembly method therefor, and dielectric filter |
US9941564B2 (en) | 2012-12-10 | 2018-04-10 | Zte Corporation | Dielectric resonator, assembly method therefor, and dielectric filter |
WO2023138088A1 (en) * | 2022-01-21 | 2023-07-27 | Telefonaktiebolaget Lm Ericsson (Publ) | Isolation-filtering unit |
Also Published As
Publication number | Publication date |
---|---|
EP0197653B1 (en) | 1991-11-21 |
EP0197653A3 (en) | 1988-06-22 |
CA1229389A (en) | 1987-11-17 |
AU575469B2 (en) | 1988-07-28 |
JPS61230501A (en) | 1986-10-14 |
ATE69671T1 (en) | 1991-12-15 |
AU5484886A (en) | 1986-10-09 |
DE3682523D1 (en) | 1992-01-02 |
JPH0733001U (en) | 1995-06-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4686496A (en) | Microwave bandpass filters including dielectric resonators mounted on a suspended substrate board | |
EP0197653B1 (en) | Microwave bandpass filter including dielectric resonators | |
US5432489A (en) | Filter with strip lines | |
KR100441727B1 (en) | Dielectric antenna including filter, dielectric antenna including duplexer and radio apparatus | |
US5748058A (en) | Cross coupled bandpass filter | |
JPS63258101A (en) | Microwave filter | |
US11303004B2 (en) | Microstrip-to-waveguide transition including a substrate integrated waveguide with a 90 degree bend section | |
US7355496B2 (en) | Finline type microwave band-pass filter | |
US4542358A (en) | Device protecting a coaxial cable against high-powered, low-frequency spurious pulses | |
US4867704A (en) | Fixture for coupling coaxial connectors to stripline circuits | |
US6812808B2 (en) | Aperture coupled output network for ceramic and waveguide combiner network | |
US6175286B1 (en) | Dielectric resonator and dielectric filter using the same | |
EP0943161B1 (en) | Microwave resonator | |
US4906957A (en) | Electrical circuit interconnect system | |
JP2630387B2 (en) | Dielectric filter | |
CA1283958C (en) | Suspended stripline rat race mixer with simplified i.f. extraction | |
EP0162506A1 (en) | Receiving arrangement for HF signals | |
US4970477A (en) | Microwave adjustment device for a transition between a hollow waveguide and a plane transmission line | |
JPS625702A (en) | Band-pass filter | |
JP4105017B2 (en) | Waveguide type dielectric filter | |
EP3490055A1 (en) | A multi-mode cavity filter | |
US4871988A (en) | Microwave transmission line of the symmetrical type and with two coplanar conductors | |
JPH03195102A (en) | Band erasing filter for microwave waveguide | |
JPH08307115A (en) | Transformer coupling method and transformer coupler | |
JP2002111329A (en) | Dielectric resonator and filter |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT CH DE FR GB LI NL SE |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT CH DE FR GB LI NL SE |
|
17P | Request for examination filed |
Effective date: 19881128 |
|
17Q | First examination report despatched |
Effective date: 19900206 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT CH DE FR GB LI NL SE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19911121 Ref country code: NL Effective date: 19911121 Ref country code: LI Effective date: 19911121 Ref country code: CH Effective date: 19911121 Ref country code: AT Effective date: 19911121 |
|
REF | Corresponds to: |
Ref document number: 69671 Country of ref document: AT Date of ref document: 19911215 Kind code of ref document: T |
|
REF | Corresponds to: |
Ref document number: 3682523 Country of ref document: DE Date of ref document: 19920102 |
|
ET | Fr: translation filed | ||
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19950309 Year of fee payment: 10 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19961203 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20010307 Year of fee payment: 16 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20010313 Year of fee payment: 16 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20020306 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20020306 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20021129 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |