EP2203953B1 - Tunable filter and method of use thereof - Google Patents
Tunable filter and method of use thereof Download PDFInfo
- Publication number
- EP2203953B1 EP2203953B1 EP08846190.0A EP08846190A EP2203953B1 EP 2203953 B1 EP2203953 B1 EP 2203953B1 EP 08846190 A EP08846190 A EP 08846190A EP 2203953 B1 EP2203953 B1 EP 2203953B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- primary
- resonating
- adjustment
- tunable filter
- resonator
- 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.)
- Active
Links
- 238000000034 method Methods 0.000 title claims description 13
- 230000008878 coupling Effects 0.000 claims description 28
- 238000010168 coupling process Methods 0.000 claims description 28
- 238000005859 coupling reaction Methods 0.000 claims description 28
- 239000004020 conductor Substances 0.000 claims description 7
- 230000004044 response Effects 0.000 claims description 5
- 239000003989 dielectric material Substances 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000008859 change Effects 0.000 description 6
- 238000004891 communication Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000005672 electromagnetic field Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002305 electric material Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 101150077194 CAP1 gene Proteins 0.000 description 1
- 101150014715 CAP2 gene Proteins 0.000 description 1
- 101100245221 Mus musculus Prss8 gene Proteins 0.000 description 1
- 101100260872 Mus musculus Tmprss4 gene Proteins 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—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
- This invention relates to a tunable filter and a method of use thereof.
- the invention relates to communication apparatus incorporating a tunable filter and method of use of said communication apparatus.
- the microwave region of the electromagnetic spectrum is an essential yet finite resource used by both civilian and military applications such as radar, navigation and wireless communications.
- Mobile radio communications require careful allocation of the spectrum by the relevant national or international authorities to service providers, who in turn may divide their slots into narrower sub bands for allocation to individual operators.
- Providers must have sufficient flexibility to re-allocate frequencies rapidly, leading to the requirement for tunable filters.
- sub band filters are generally smaller, easier and therefore cheaper to manufacture, without the ability to tune them in the field, providers are forced to buy multiple products to cover the entire band and to physically swap filters out of base stations as circumstances and adjacent operators change.
- Tunable filters allow operators to purchase one product only and align it to the desired operating frequency and bandwidth in the field.
- filters have comprised a conductive housing defining a plurality of resonant cavities with a resonator located in each cavity.
- a pre-determined electromagnetic coupling strength between the resonators.
- Each resonator has a natural resonating frequency and therefore each resonator typically has to be tuned manually due to production build and mechanical part tolerances to achieve a pre-determined frequency for all the resonators.
- This tuning is typically performed using an adjustment screw located in a lid of the filter housing above each cavity. Additional fine adjustment of the electromagnetic coupling strength may also be required and tuning is typically achieved by an adjustment of a tuning screw located within the conductive housing within or around the area at which the coupling takes place.
- filters which allow tuning of all the resonators of the filter substantially simultaneously, thereby allowing post deployment tuning and reducing associated time and costs.
- Typical examples of such prior art filters are disclosed in US5841330 , US 2007/0052495 , and US7180391 .
- the filters contain a plurality of resonant cavities, each cavity comprising a resonator contained within an outer conductor and a dielectric tuner held by a holder.
- the holders of all the dielectric tuners in the filter are connected together such that they can be moved simultaneously as a group or individually, allowing the dielectrics to adjust the resonator frequencies substantially equally or individually, allowing each resonator frequency to be adjusted independently of the others.
- a tunable filter as set out in product claim 1.
- the tunable filter of the present invention allows either or both of:
- an adjuster element is introduced into each resonant cavity to influence the frequency of a primary resonator located in said cavity.
- the primary resonator is fixed and the adjuster element is movable.
- secondary resonating means are associated with each primary resonating means to influence the frequency of the primary resonating means and the adjustment means are provided to allow adjustment of coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator.
- the filter of the present invention therefore has the advantage that the filter is easier to manufacture, it allows complete filter parametric adjustment to be achieved and the filter is less sensitive to adjustments, thereby allowing tuning of the filter to be more consistently reproducible compared to prior art filters.
- the rate of change of adjustment of the coupling between the primary-secondary resonator pair can be adjusted allowing a greater potential tuning range of the filter characteristics.
- the secondary resonating means can be located in a cavity of the tunable filter with a primary resonating means or can be located externally of the cavity housing the primary resonating means. In either embodiment the secondary resonating means is located in such a position and manner to allow coupling with the primary resonating means with which it is associated.
- the filter housing is formed from conductive material. Further preferably the conductive housing has a plurality of cavities defined therein for the location of at least the primary resonating means and preferably the primary-secondary resonating pair.
- the primary resonating means is arranged so as to resonate close to the desired operating frequency of the filter.
- Tuning means are typically associated with each primary resonating means to allowing tuning of the primary resonating means to a pre-determined or first frequency on manufacture or initial set up of said filter. Thereafter, tuning of the primary resonating means takes place via the adjustment means in accordance with the present invention.
- the tuning means are preferably located directly above the primary resonating means in the cavity (i.e. substantially vertically above and within the outer perimeter of the primary resonating means).
- the secondary resonating means are provided with tuning means for allowing the secondary resonating means to be tuned to a pre-determined frequency or second frequency.
- the tuning means of the secondary resonating means can be integrally formed therewith or can be located a spaced distance from the secondary resonating means (i.e. the tuning means could be located a spaced distance above the secondary resonating means in one example).
- the tuning means can be in the form of a rotatable threaded screw and/or the like. Once the pre-determined frequency is achieved, the tuning means can be locked via locking means, such as for example by a locking nut and/or the like. It is not essential that separate locking means are used with the tuning means since the tuning means could be self locking and could be moved manually or automatically (i.e. without direct user actuation) using drive means and/or the like.
- the secondary resonating means is substantially fixed relative to the housing following set-up of the filter (i.e. once any tuning means, if present, have been locked).
- the primary resonating means are substantially fixed relative to the housing following set-up of the filter (i.e. once tuning means if present have been locked).
- the adjustment means are typically movable relative to the primary and/or secondary resonating means.
- the primary and secondary resonating means are substantially fixed and the adjustment means are movable relative to both said primary and secondary resonating means.
- the primary resonating means in each of the two of more cavities of the filter are coupled together to form the required filter response.
- the adjustment means for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator are arranged such that each resonator pair and/or secondary resonator means are adjusted substantially independently of each other and/or of other resonator pairs and/or secondary resonator means in the filter.
- the adjustment means for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator are connected via connection means such that each resonator pair and/or secondary resonator means can be adjusted substantially simultaneously.
- a first adjustment means in order to achieve adjustment of the centre frequency of the filter, can be used to influence the coupling within the primary-secondary resonator pair.
- second adjustment means are used in addition to or as an alternative to the first adjustment means to influence the resonating frequency of the secondary resonating means. Both the first and second adjustment means can be controlled remotely without a user having the access the interior of the cavity to make the adjustment.
- the first adjustment means are capable of adjusting the coupling within the primary-secondary resonating pair
- the first adjustment means are preferably located laterally of the primary resonating means and between the primary and secondary resonating means.
- the first adjustment means of two or more primary-secondary resonating pairs in the filter can be connected together via connection means. This allows the coupling within each primary-secondary resonating pair of the two or more primary-secondary resonating pairs to be adjusted substantially simultaneously.
- the second adjustment means are capable of adjusting the resonating frequency of the secondary resonating means
- the second adjustment means can be located laterally of the secondary resonating means or, in one embodiment, can be located above or integraly with the secondary resonating means.
- the second adjustment means of two or more secondary resonating means can be connected together via connection means. This allows the frequency of two or more secondary resonating means to be adjusted substantially simultaneously.
- connection means can be any suitable connection means.
- the connection means can include any suitable linkage means, mechanical means and/or the like.
- the adjustment means can be joined to control means in the form of an elongate rod, any other suitably shaped rod and/or the like.
- the connection means could be electrical means, such as for example a diode adjuster, connected via a circuit board, suitable electrical circuitry and/or the like. Adjustment of any electrical parameters through the electrical means could result in adjustment of the coupling of the resonator pair and/or the resonating frequency of the secondary resonating means.
- connection means can be moved in a substantially horizontal plane or in a plane substantially parallel to the lid of the filter.
- the connection means can be moved from side to side in a direction substantially parallel to the longitudinal axis of the filter.
- connection means could be slidably movable, pivotably movable and/or rotatable.
- connection means could be a ring or disc member located with the lid of the filter to which the adjustment means are connected at spaced apart intervals therealong. Rotation of the connection means could cause sliding movement of the adjustment means relative to the primary and/or secondary resonating means.
- connection means are located underneath the lid of the filter and movable within the cavities of the filter, thereby substantially preventing electrical leakage from the filter.
- connection means could be located on top of or above the lid or cavity walls of the filter and movable relative thereto if required.
- Guide means can be associated with the connection means to help guide the connection means during movement of the same and for supporting the same.
- the guide means could include one or more guide channels defined in the housing of the filter.
- adjustment of the adjustment means can be undertaken manually.
- adjustment of the adjustment means can be undertaken automatically using suitable drive means.
- the drive means can include any or any combination electrical, pneumatic, mechanical, hydraulic means and/or the like and can be connected to the adjustment means directly or the connection means.
- one or more electrically powered motors can be used to drive the adjustment means and/or connection means.
- Control means can be associated with the adjustment means and/or connection means to allow control of the adjustment. Control of the adjustment means can be undertaken remotely.
- the adjustment means includes one or more adjustment elements.
- the adjustment means can be formed at least in part from dielectric material or from conductive material. In the case of di-electric material, the adjustment means can engage or abut with the primary and/or secondary resonating means. In the case of conductive material, the adjustment means are typically a spaced distance apart from the primary and/or secondary resonating means.
- the adjustment means can be located internally or externally of the cavity and preferably in either embodiment movement of the adjustment means relative to the primary and/or secondary resonating means influences the coupling within the primary-secondary pair and/or resonating frequency of the secondary resonating means.
- the adjustment means are preferably capable of undergoing rotatable, pivotable and/or slideable movement during the adjustment process.
- Each associated primary and secondary resonating means are typically located a spaced distance apart and laterally from each other.
- the primary and secondary resonating means can be located at any suitable position within a cavity of the filter providing the secondary resonating means can influence the primary resonating means in use.
- the secondary resonating means of a primary-secondary resonating pair can be located in a separate cavity to the primary resonating means with which it is associated or coupled.
- the primary resonating means is preferably located on a base, side wall and /or on a lid of the defined cavity. It can take the form of a solid post, hollow cylindrical post and/or the like.
- the secondary resonating means can be located on a base, side wall and/or on a lid associated with the cavity and also take the form of a solid post, hollow cylindrical post and/or the like. In either case the primary and secondary resonating means are of such a form, size, shape and/or material to allow them to resonate at a desired resonating frequency.
- first adjustment means can be provided to adjust the coupling between the primary-secondary resonating pair and at least second adjustment means can be provided to adjust the resonating frequency of the secondary resonating means.
- the difference between the first and second frequencies of the between the primary and secondary resonating means is less than or substantially equal to three times the resonating frequency of the primary resonating means.
- coupling refers to any arrangement whereby the electromagnetic fields of two or more parts of the filter, the primary resonating means, the secondary resonating means and/or the adjustment means are electromagnetically connected together or influence each other (i.e. the parts or means are mutually affected by the same electromagnetic field).
- the primary and/or secondary resonating means can take any suitable size, shape and/or form in which they can resonate at one or more desired frequencies and can be coupled to each other.
- the primary and/or secondary resonating means are in the form of a conductive post like element protruding inwardly into a cavity defined by one or more surfaces of the filter housing.
- the present invention has the advantages over the prior art in that complete filter parametric adjustment can be achieved, the bandwidth of the filter can be increased or reduced, a greater overall tunable frequency range can be achieved and a simpler mechanical implementation can be utilised.
- the filter includes a conductive housing defining a plurality of cavities therein. Each cavity has a primary resonator (R) located therein. An adjuster (not shown) is provided in each cavity to allow adjustment of the frequency of each primary resonator. Adjustment of the adjuster has the effect of changing the loading capacitance (Cap) to the resonator R.
- the adjusters of least two resonators (R1, R2; R(n-1), R(n)) are connected together so that the frequency of each resonator R1, R2; R(n-1), R(n) can be adjusted substantially simultaneously. This results in the loading capacitance (Cap1, Cap2; Cap(n-1), Cap(n)) of each resonator being adjusted substantially simultaneously by equal amounts.
- FIG. 2 there is illustrated a simplified circuit diagram of a tunable filter according to an embodiment of the present invention.
- the filter includes a conductive housing defining a plurality of cavities therein. Each cavity contains a Primary Resonator (PR) and a Secondary Resonator (AR) electromagnetically coupled (CA) to the PR, to form a primary-Secondary resonator pair. Adjustment means (not shown) are associated with each cavity to allow adjustment of the coupling between said primary-secondary resonator pairs. Adjustment of the adjustment means has the effect of changing the resonant frequency of the resonator PR.
- the adjusters of least two primary resonators PR1, PR2; PR(n-1), PR(n) are connected together so that the frequency of each primary resonator PR can be adjusted substantially simultaneously thus changing the frequency of the filter parameters.
- the adjustment means can be arranged so as to adjust the frequency of the secondary resonator and/or the coupling between each Primary-Secondary pair, thereby changing the centre frequency of the filter, and/or bandwidth of the filter.
- FIGS. 3a and 3b show cross sectional views of a top and side of one section of a tunable filter according to an embodiment of the present invention. More particularly, the section is defined in a housing 4 having a base 6, side walls 8 and a lid 10.
- the housing is formed from conductive material, such as for example metal.
- a cavity 2 is defined between the base, side walls and a lid. The cavity is typically one of a plurality of cavities defined in the housing of the filter but only one cavity is shown in these figures for the purposes of clarity.
- a primary resonator 12 in the form of a conductive post is located on base 6 of the cavity 2 and protrudes upwardly into the cavity.
- Tuning means in the form of a frequency adjustment screw 14 is inserted through lid 10 to allow tuning of the primary resonator 12 during manufacture of the filter.
- Screw 14 is in the form of a threaded screw having locking means in the form of a locking nut 16 located thereon.
- a secondary resonator 18 in the form of a conductive post is located on base 6 of the cavity 2 and also protrudes upwardly into the cavity.
- the size, material and/or position of the secondary resonator 18 is such so as to allow electromagnetic coupling with the primary resonator 12 to form a primary-secondary resonator pair.
- Adjustment means in the form of an adjuster element 20 is pivotally mounted in cavity 2 and is located between the primary resonator 12 and the secondary resonator 18.
- the purpose of the adjuster element is to adjust the electromagnetic coupling between the primary and secondary resonators 12, 18 (i.e. adjust the coupling within the primary-secondary resonator pair).
- the adjuster element can be formed from di-electric material or conductive material as required.
- element 20 is pivotable about a substantially horizontal axis. However, it will be appreciated that the adjuster element can be moved through any suitable angle and/or about any suitable axis providing that suitable adjustment of the coupling between the primary-secondary resonator pair is achieved.
- Pivotal movement of adjuster element 20, as shown by arrow 22, influences the electromagnetic field within the primary-secondary resonator pair. This causes a change in the centre operating frequency of the primary resonator 12. This in turn changes the loading of the primary resonator thus changing the resonating frequency associated with therewith.
- the secondary resonator 18 can be located in any suitable position within or externally to cavity 2 providing it is coupled to primary resonator 12.
- figures 4a and 4b illustrates a similar filter to that of figures 3a and 3b but secondary resonator 18 is attached to lid 10 in this embodiment.
- tuning means in the form of a screw thread 24 is associated with an external end of secondary resonator 18 to allow the frequency of secondary resonator 18 to be tuned during manufacture of the filter.
- Locking means in the form of a locking nut 26 can be provided on screw thread 24 to lock the same once initial tuning has taken place.
- the opposite end of resonator 18 protrudes into cavity 2 and projects downwardly into the cavity (i.e. protrudes in an opposite direction to primary resonator 12).
- the tuning means could also be used as second adjustment means for adjustment of the resonating frequency of the secondary resonator 18 even after initial set up of the filter.
- a self locking screw 24 could be used which is integral with the secondary resonator 18 to allow movement of the secondary resonator after initial set up of the filter has been completed.
- adjuster element 20 is slidably mounted in the cavity 2 for sliding movement between the primary resonator 12 and secondary resonator 18, as shown by arrow 28. Sliding movement of adjuster element 20 acts in a similar manner to the adjuster element in figures 3a and 3b to influence the coupling within the primary-secondary resonator pair, thereby changing the frequency of the primary resonator.
- a filter typically includes a plurality of cavities defined therein and each cavity typically contains a primary-secondary resonator pair and an adjustment element, as shown in figures 5a-6c . More particularly, figures 5a-5c illustrate a filter housing 100 having five sections or cavities 102 defined therein. Each cavity communicates with an adjacent cavity via an iris or aperture. 103.
- the filter housing 100 has a base 106, side walls 108 and a lid 110.
- a primary resonator 112 is located in each cavity 102 and has tuning means in the form of an adjustment screw 114 located in lid 110 and associated with each resonator 112. This allows each of the plurality of primary resonators to be individually and independently tuned during manufacture of the filter.
- a locking nut 116 is provided to lock the adjustment screw in place once it has been correctly positioned.
- Transformers 109 are used to electromagnetically couple the signal to/from the input/output connectors 111 to the cavities.
- a secondary resonator 118 is attached to lid 110 and protrudes inwardly of the cavity in a direction towards base 106.
- a screw thread 124 is associated with an external lid end of resonator 118 to allow tuning of the secondary resonator 118 on manufacture and a locking nut 126 is provided to lock screw 124 following tuning, as previously described in figures 4a-4b .
- An adjuster element 120 is located in each cavity 102 and the adjuster elements 120 of all five cavities are connected together via connection means in the form of a common control rod 128.
- Control rod 128 is slidably mounted within housing 100 to allow all five adjuster elements 120 to be slidably moved substantially simultaneously on actuation of the control rod. More particularly, control rod 128 is slidably mounted in a plurality of guide channels defined in an upper edge of the side walls of the housing.
- Figures 5a-5c illustrate a first position of the adjuster elements 120 and figures 6a-6c illustrate a second position of the adjuster elements 120 following actuation of control rod 128 in use.
- Actuation of the control 128 can be performed manually or can be performed automatically using for exampled one or more powered motors. In either case actuation of control 128 can be performed directly or remotely.
- Figure 7 illustrates how the frequency of the filter in figures 5a-6c can be adjusted on moving the adjuster elements 20 from the first to the second position.
- Lines 'A' and 'B' show the lowest and highest operating frequencies of the filter following bandwidth adjustment.
- the centre operating frequency of the filter can be adjusted using the described invention.
- FIGS. 8a-8b there is illustrated a further embodiment of the present invention in which the range of the bandwidth of the filter can be increased or decreased.
- This embodiment can be used and/or can be provided independently of the embodiments previously described or can be used and/or can be provided in combination with the previously described figures.
- a single cavity of a multiple cavity tuner is illustrated in figures 8a-8b . Similar reference numbers have been used to denote similar features in figures 4a and 4b .
- a second conductive or dielectric adjuster element 200 is provided between the side wall 8 of the filter housing and the secondary resonator 18. Provision of the second adjuster element 200 in the cavity allows the resonant frequency of the secondary resonator 18 to be adjusted independently of the primary resonator 12 by a sliding movement as indicated by the arrow 222.
- a filter typically includes a plurality of cavities defined therein and each cavity typically contains a primary-secondary resonator pair and an adjustment element.
- Figure 9a , 9b and 9c show a similar filter to the one in figure 5a , 5b and 5c with an additional second tunable element 131 enabling the tuning adjustment of the resonant frequency of the secondary resonator 130.
- Control rod 128 is slidably mounted within housing 100 to allow all five additional adjuster elements 131 to be slidably moved substantially simultaneously on actuation of the control rod. More particularly, control rod 128 is slidably mounted in a plurality of guide channels defined in an upper edge of the side walls of the housing.
- Figures 9a-9c illustrate a first position of the adjuster elements 131 and figures 10a-10c illustrate a second position of the adjuster elements 131 following actuation of control rod 128 in use. This allows the frequency of all the secondary resonators 130 to be adjusted by a substantially equal amount substantially simultaneously, thereby creating an accurate and substantially reproducible tuning method for the filter bandwidth and frequency.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Description
- This invention relates to a tunable filter and a method of use thereof. In addition, the invention relates to communication apparatus incorporating a tunable filter and method of use of said communication apparatus.
- The microwave region of the electromagnetic spectrum is an essential yet finite resource used by both civilian and military applications such as radar, navigation and wireless communications. Mobile radio communications require careful allocation of the spectrum by the relevant national or international authorities to service providers, who in turn may divide their slots into narrower sub bands for allocation to individual operators. Providers must have sufficient flexibility to re-allocate frequencies rapidly, leading to the requirement for tunable filters. Although sub band filters are generally smaller, easier and therefore cheaper to manufacture, without the ability to tune them in the field, providers are forced to buy multiple products to cover the entire band and to physically swap filters out of base stations as circumstances and adjacent operators change. Tunable filters allow operators to purchase one product only and align it to the desired operating frequency and bandwidth in the field.
- Conventionally, filters have comprised a conductive housing defining a plurality of resonant cavities with a resonator located in each cavity. In order to obtain a required frequency response from the filter, it is necessary to have a pre-determined electromagnetic coupling strength between the resonators. Each resonator has a natural resonating frequency and therefore each resonator typically has to be tuned manually due to production build and mechanical part tolerances to achieve a pre-determined frequency for all the resonators. This tuning is typically performed using an adjustment screw located in a lid of the filter housing above each cavity. Additional fine adjustment of the electromagnetic coupling strength may also be required and tuning is typically achieved by an adjustment of a tuning screw located within the conductive housing within or around the area at which the coupling takes place. Turning of the resonator adjustment screw changes the capacitance between the resonator and the lid and therefore changes the frequency of the resonator. By tuning each resonator of the filter in this manner, the performance of the filter can be tuned to a required response. A problem with this type of tuning is that it is time consuming, expensive and impractical once the tuning screws have been locked post deployment in the field.
- In order to overcome this problem, it is known to provide filters which allow tuning of all the resonators of the filter substantially simultaneously, thereby allowing post deployment tuning and reducing associated time and costs. Typical examples of such prior art filters are disclosed in
US5841330 ,US 2007/0052495 , andUS7180391 . The filters contain a plurality of resonant cavities, each cavity comprising a resonator contained within an outer conductor and a dielectric tuner held by a holder. The holders of all the dielectric tuners in the filter are connected together such that they can be moved simultaneously as a group or individually, allowing the dielectrics to adjust the resonator frequencies substantially equally or individually, allowing each resonator frequency to be adjusted independently of the others. As the position and/or angle of the dielectric with respect to each resonator is varied, perturbation is applied to the electric field occurring in the resonant cavity, changing the capacitive loading at the upper end of the resonator, so that the resonant frequency of each cavity resonator may be varied. The amount of capacitive change limits the range of frequency shift. A problem with the above filters is that in connecting the dielectric holders in such a way to allow simultaneous and/or individual movement, it requires a complicated mechanical structure which leads to possible cost and performance issues and significantly increases assembly and alignment times when compared with a fixed frequency band filter. - It is therefore an aim of the present invention to produce a tunable filter which resolves the issues described above.
- It is a further aim of the present invention to provide a method of using a tunable filter.
- It is a yet further aim of the present invention to provide communication apparatus incorporating a tunable filter and a method of using said communication apparatus.
- According to a first aspect of the present invention there is provided a tunable filter, as set out in
product claim 1. - Thus, the tunable filter of the present invention allows either or both of:
- a) the centre operating frequency of the filter to be moved to a different frequency; and/or
- b) the bandwidth of the filter to be changed (i.e. for the size of the bandwidth to be increased or decreased to cover a greater or reduced frequency range).
- This is in contrast to prior art tunable filters which only allow adjustment of the centre operating frequency. In addition, the means of adjusting the centre frequency in prior art tunable filters is different to that of the present invention.
- In prior art tunable filters, an adjuster element is introduced into each resonant cavity to influence the frequency of a primary resonator located in said cavity. The primary resonator is fixed and the adjuster element is movable. In the present invention, secondary resonating means are associated with each primary resonating means to influence the frequency of the primary resonating means and the adjustment means are provided to allow adjustment of coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator. The filter of the present invention therefore has the advantage that the filter is easier to manufacture, it allows complete filter parametric adjustment to be achieved and the filter is less sensitive to adjustments, thereby allowing tuning of the filter to be more consistently reproducible compared to prior art filters. Furthermore, by adjusting the resonant frequency of the secondary resonator the rate of change of adjustment of the coupling between the primary-secondary resonator pair can be adjusted allowing a greater potential tuning range of the filter characteristics.
- The secondary resonating means can be located in a cavity of the tunable filter with a primary resonating means or can be located externally of the cavity housing the primary resonating means. In either embodiment the secondary resonating means is located in such a position and manner to allow coupling with the primary resonating means with which it is associated.
- Preferably the filter housing is formed from conductive material. Further preferably the conductive housing has a plurality of cavities defined therein for the location of at least the primary resonating means and preferably the primary-secondary resonating pair.
- The primary resonating means is arranged so as to resonate close to the desired operating frequency of the filter. Tuning means are typically associated with each primary resonating means to allowing tuning of the primary resonating means to a pre-determined or first frequency on manufacture or initial set up of said filter. Thereafter, tuning of the primary resonating means takes place via the adjustment means in accordance with the present invention. The tuning means are preferably located directly above the primary resonating means in the cavity (i.e. substantially vertically above and within the outer perimeter of the primary resonating means).
- In one embodiment the secondary resonating means are provided with tuning means for allowing the secondary resonating means to be tuned to a pre-determined frequency or second frequency. The tuning means of the secondary resonating means can be integrally formed therewith or can be located a spaced distance from the secondary resonating means (i.e. the tuning means could be located a spaced distance above the secondary resonating means in one example).
- The tuning means can be in the form of a rotatable threaded screw and/or the like. Once the pre-determined frequency is achieved, the tuning means can be locked via locking means, such as for example by a locking nut and/or the like. It is not essential that separate locking means are used with the tuning means since the tuning means could be self locking and could be moved manually or automatically (i.e. without direct user actuation) using drive means and/or the like.
- In one embodiment the secondary resonating means is substantially fixed relative to the housing following set-up of the filter (i.e. once any tuning means, if present, have been locked). Preferably the primary resonating means are substantially fixed relative to the housing following set-up of the filter (i.e. once tuning means if present have been locked). The adjustment means are typically movable relative to the primary and/or secondary resonating means.
- Thus, in contract to prior art filters in one embodiment of the present invention, the primary and secondary resonating means are substantially fixed and the adjustment means are movable relative to both said primary and secondary resonating means.
- The primary resonating means in each of the two of more cavities of the filter are coupled together to form the required filter response.
- In one embodiment the adjustment means for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator are arranged such that each resonator pair and/or secondary resonator means are adjusted substantially independently of each other and/or of other resonator pairs and/or secondary resonator means in the filter.
- In an alternative embodiment the adjustment means for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonator are connected via connection means such that each resonator pair and/or secondary resonator means can be adjusted substantially simultaneously.
- In a preferred embodiment, in order to achieve adjustment of the centre frequency of the filter, a first adjustment means can be used to influence the coupling within the primary-secondary resonator pair. In order to achieve a change in the bandwidth of the filter, second adjustment means are used in addition to or as an alternative to the first adjustment means to influence the resonating frequency of the secondary resonating means. Both the first and second adjustment means can be controlled remotely without a user having the access the interior of the cavity to make the adjustment.
- Thus, in the embodiment wherein the first adjustment means are capable of adjusting the coupling within the primary-secondary resonating pair, the first adjustment means are preferably located laterally of the primary resonating means and between the primary and secondary resonating means.
- In one embodiment the first adjustment means of two or more primary-secondary resonating pairs in the filter can be connected together via connection means. This allows the coupling within each primary-secondary resonating pair of the two or more primary-secondary resonating pairs to be adjusted substantially simultaneously.
- In the embodiment wherein the second adjustment means are capable of adjusting the resonating frequency of the secondary resonating means, the second adjustment means can be located laterally of the secondary resonating means or, in one embodiment, can be located above or integraly with the secondary resonating means.
- In one embodiment the second adjustment means of two or more secondary resonating means can be connected together via connection means. This allows the frequency of two or more secondary resonating means to be adjusted substantially simultaneously.
- The connection means can be any suitable connection means. The connection means can include any suitable linkage means, mechanical means and/or the like. For example, the adjustment means can be joined to control means in the form of an elongate rod, any other suitably shaped rod and/or the like. Alternatively, or in addition, the connection means could be electrical means, such as for example a diode adjuster, connected via a circuit board, suitable electrical circuitry and/or the like. Adjustment of any electrical parameters through the electrical means could result in adjustment of the coupling of the resonator pair and/or the resonating frequency of the secondary resonating means.
- In one embodiment the connection means can be moved in a substantially horizontal plane or in a plane substantially parallel to the lid of the filter. For example, the connection means can be moved from side to side in a direction substantially parallel to the longitudinal axis of the filter. However, the connection means could be slidably movable, pivotably movable and/or rotatable. For example, the connection means could be a ring or disc member located with the lid of the filter to which the adjustment means are connected at spaced apart intervals therealong. Rotation of the connection means could cause sliding movement of the adjustment means relative to the primary and/or secondary resonating means.
- In a preferred embodiment the connection means are located underneath the lid of the filter and movable within the cavities of the filter, thereby substantially preventing electrical leakage from the filter. However, the connection means could be located on top of or above the lid or cavity walls of the filter and movable relative thereto if required.
- Guide means can be associated with the connection means to help guide the connection means during movement of the same and for supporting the same. The guide means could include one or more guide channels defined in the housing of the filter.
- In one embodiment adjustment of the adjustment means can be undertaken manually.
- In one embodiment adjustment of the adjustment means can be undertaken automatically using suitable drive means. The drive means can include any or any combination electrical, pneumatic, mechanical, hydraulic means and/or the like and can be connected to the adjustment means directly or the connection means. For example, one or more electrically powered motors can be used to drive the adjustment means and/or connection means.
- Control means can be associated with the adjustment means and/or connection means to allow control of the adjustment. Control of the adjustment means can be undertaken remotely.
- In one embodiment the adjustment means includes one or more adjustment elements. The adjustment means can be formed at least in part from dielectric material or from conductive material. In the case of di-electric material, the adjustment means can engage or abut with the primary and/or secondary resonating means. In the case of conductive material, the adjustment means are typically a spaced distance apart from the primary and/or secondary resonating means.
- The adjustment means can be located internally or externally of the cavity and preferably in either embodiment movement of the adjustment means relative to the primary and/or secondary resonating means influences the coupling within the primary-secondary pair and/or resonating frequency of the secondary resonating means.
- The adjustment means are preferably capable of undergoing rotatable, pivotable and/or slideable movement during the adjustment process.
- Each associated primary and secondary resonating means are typically located a spaced distance apart and laterally from each other. For example, in one embodiment the primary and secondary resonating means can be located at any suitable position within a cavity of the filter providing the secondary resonating means can influence the primary resonating means in use. In one embodiment the secondary resonating means of a primary-secondary resonating pair can be located in a separate cavity to the primary resonating means with which it is associated or coupled.
- The primary resonating means is preferably located on a base, side wall and /or on a lid of the defined cavity. It can take the form of a solid post, hollow cylindrical post and/or the like. The secondary resonating means can be located on a base, side wall and/or on a lid associated with the cavity and also take the form of a solid post, hollow cylindrical post and/or the like. In either case the primary and secondary resonating means are of such a form, size, shape and/or material to allow them to resonate at a desired resonating frequency.
- In one embodiment two adjustment means can be located in or associated with each cavity. Thus, for example, first adjustment means can be provided to adjust the coupling between the primary-secondary resonating pair and at least second adjustment means can be provided to adjust the resonating frequency of the secondary resonating means.
- Preferably the difference between the first and second frequencies of the between the primary and secondary resonating means is less than or substantially equal to three times the resonating frequency of the primary resonating means.
- The term coupling used herein refers to any arrangement whereby the electromagnetic fields of two or more parts of the filter, the primary resonating means, the secondary resonating means and/or the adjustment means are electromagnetically connected together or influence each other (i.e. the parts or means are mutually affected by the same electromagnetic field).
- The primary and/or secondary resonating means can take any suitable size, shape and/or form in which they can resonate at one or more desired frequencies and can be coupled to each other. In a preferred embodiment the primary and/or secondary resonating means are in the form of a conductive post like element protruding inwardly into a cavity defined by one or more surfaces of the filter housing.
- According to a second aspect of the present invention there is provided a method of adjusting the operating frequency and/or bandwidth of a tunable filter, as set out in method claim 15.
- The present invention has the advantages over the prior art in that complete filter parametric adjustment can be achieved, the bandwidth of the filter can be increased or reduced, a greater overall tunable frequency range can be achieved and a simpler mechanical implementation can be utilised.
- Embodiments of the present invention will now be described with reference to the following figures, wherein:
-
Figure 1 shows a simplified circuit diagram of a tunable filter design illustrating the basic principles of the prior art; -
Figure 2 shows a simplified circuit diagram of a tunable filter design illustrating the basic principle of the present invention in one embodiment; -
Figures 3a and3b show cross sections of a top and a side respectively of part of a filter according to a first embodiment of the present invention showing a primary-secondary resonator pair and coupling adjustment; -
Figures 4a and4b show cross sections of a top and side respectively of part of a filter according to a second embodiment of the present invention showing a primary-secondary resonator pair and coupling adjustment; -
Figures 5a ,5b and5c show cross sections of a top, side and end respectively of a five section tunable filter in a first operating position according to an embodiment of the present invention; -
Figures 6a ,6b and6c show cross sections of a top, side and end respectively of the five section tunable filter infigures 5a-5c in a second operating position according to an embodiment of the present invention; -
Figure 7 illustrates a graph of Frequency vs Return/Insertion Loss and shows a change in the operating frequency of the filters infigures 5a-6c following adjustment of the adjustment means. -
Figures 8a and8b show cross sections of a top and side respectively of part of a tunable filter according to a further embodiment of the present invention. -
Figures 9a ,9b and9c show cross sections of a top, side and end respectively of a five section tunable filter in a first operating position according to a further embodiment of the present invention; and -
Figures 10a ,10b and10c show cross sections of a top, side and end respectively of the five sectioned tunable filter infigures 9a-9c in a second operating position. - Referring firstly to
Figure 1 , there is illustrated a simplified circuit diagram of a tunable filter of the prior art. The filter includes a conductive housing defining a plurality of cavities therein. Each cavity has a primary resonator (R) located therein. An adjuster (not shown) is provided in each cavity to allow adjustment of the frequency of each primary resonator. Adjustment of the adjuster has the effect of changing the loading capacitance (Cap) to the resonator R. The adjusters of least two resonators (R1, R2; R(n-1), R(n)) are connected together so that the frequency of each resonator R1, R2; R(n-1), R(n) can be adjusted substantially simultaneously. This results in the loading capacitance (Cap1, Cap2; Cap(n-1), Cap(n)) of each resonator being adjusted substantially simultaneously by equal amounts. - In
Figure 2 there is illustrated a simplified circuit diagram of a tunable filter according to an embodiment of the present invention. The filter includes a conductive housing defining a plurality of cavities therein. Each cavity contains a Primary Resonator (PR) and a Secondary Resonator (AR) electromagnetically coupled (CA) to the PR, to form a primary-Secondary resonator pair. Adjustment means (not shown) are associated with each cavity to allow adjustment of the coupling between said primary-secondary resonator pairs. Adjustment of the adjustment means has the effect of changing the resonant frequency of the resonator PR. The adjusters of least two primary resonators (PR1, PR2; PR(n-1), PR(n)) are connected together so that the frequency of each primary resonator PR can be adjusted substantially simultaneously thus changing the frequency of the filter parameters. - The adjustment means can be arranged so as to adjust the frequency of the secondary resonator and/or the coupling between each Primary-Secondary pair, thereby changing the centre frequency of the filter, and/or bandwidth of the filter.
- A more detailed explanation of the present invention will now be given with reference to
Figures 3a and3b . The figures show cross sectional views of a top and side of one section of a tunable filter according to an embodiment of the present invention. More particularly, the section is defined in ahousing 4 having abase 6,side walls 8 and alid 10. The housing is formed from conductive material, such as for example metal. Acavity 2 is defined between the base, side walls and a lid. The cavity is typically one of a plurality of cavities defined in the housing of the filter but only one cavity is shown in these figures for the purposes of clarity. - A
primary resonator 12 in the form of a conductive post is located onbase 6 of thecavity 2 and protrudes upwardly into the cavity. Tuning means in the form of afrequency adjustment screw 14 is inserted throughlid 10 to allow tuning of theprimary resonator 12 during manufacture of the filter.Screw 14 is in the form of a threaded screw having locking means in the form of a lockingnut 16 located thereon. Once the primary resonator has been tuned to a desired operating frequency on set up of the filter, the locking nut is locked to prevent tuning of the filter via theadjustment screw 14. - A
secondary resonator 18 in the form of a conductive post is located onbase 6 of thecavity 2 and also protrudes upwardly into the cavity. The size, material and/or position of thesecondary resonator 18 is such so as to allow electromagnetic coupling with theprimary resonator 12 to form a primary-secondary resonator pair. - Adjustment means in the form of an
adjuster element 20 is pivotally mounted incavity 2 and is located between theprimary resonator 12 and thesecondary resonator 18. The purpose of the adjuster element is to adjust the electromagnetic coupling between the primary andsecondary resonators 12, 18 (i.e. adjust the coupling within the primary-secondary resonator pair). The adjuster element can be formed from di-electric material or conductive material as required. In the illustration,element 20 is pivotable about a substantially horizontal axis. However, it will be appreciated that the adjuster element can be moved through any suitable angle and/or about any suitable axis providing that suitable adjustment of the coupling between the primary-secondary resonator pair is achieved. - Pivotal movement of
adjuster element 20, as shown byarrow 22, influences the electromagnetic field within the primary-secondary resonator pair. This causes a change in the centre operating frequency of theprimary resonator 12. This in turn changes the loading of the primary resonator thus changing the resonating frequency associated with therewith. - The
secondary resonator 18 can be located in any suitable position within or externally tocavity 2 providing it is coupled toprimary resonator 12. For example,figures 4a and4b illustrates a similar filter to that offigures 3a and3b butsecondary resonator 18 is attached tolid 10 in this embodiment. More particularly, tuning means in the form of ascrew thread 24 is associated with an external end ofsecondary resonator 18 to allow the frequency ofsecondary resonator 18 to be tuned during manufacture of the filter. Locking means in the form of a lockingnut 26 can be provided onscrew thread 24 to lock the same once initial tuning has taken place. The opposite end ofresonator 18 protrudes intocavity 2 and projects downwardly into the cavity (i.e. protrudes in an opposite direction to primary resonator 12). - It will be appreciated that the tuning means could also be used as second adjustment means for adjustment of the resonating frequency of the
secondary resonator 18 even after initial set up of the filter. For example, aself locking screw 24 could be used which is integral with thesecondary resonator 18 to allow movement of the secondary resonator after initial set up of the filter has been completed. - In this illustrated embodiment,
adjuster element 20 is slidably mounted in thecavity 2 for sliding movement between theprimary resonator 12 andsecondary resonator 18, as shown by arrow 28. Sliding movement ofadjuster element 20 acts in a similar manner to the adjuster element infigures 3a and3b to influence the coupling within the primary-secondary resonator pair, thereby changing the frequency of the primary resonator. - As mentioned previously, a filter typically includes a plurality of cavities defined therein and each cavity typically contains a primary-secondary resonator pair and an adjustment element, as shown in
figures 5a-6c . More particularly,figures 5a-5c illustrate afilter housing 100 having five sections orcavities 102 defined therein. Each cavity communicates with an adjacent cavity via an iris or aperture. 103. - The
filter housing 100 has abase 106,side walls 108 and alid 110. Aprimary resonator 112 is located in eachcavity 102 and has tuning means in the form of anadjustment screw 114 located inlid 110 and associated with eachresonator 112. This allows each of the plurality of primary resonators to be individually and independently tuned during manufacture of the filter. A lockingnut 116 is provided to lock the adjustment screw in place once it has been correctly positioned.Transformers 109 are used to electromagnetically couple the signal to/from the input/output connectors 111 to the cavities. - A
secondary resonator 118 is attached tolid 110 and protrudes inwardly of the cavity in a direction towardsbase 106. Ascrew thread 124 is associated with an external lid end ofresonator 118 to allow tuning of thesecondary resonator 118 on manufacture and a lockingnut 126 is provided to lockscrew 124 following tuning, as previously described infigures 4a-4b . - An
adjuster element 120 is located in eachcavity 102 and theadjuster elements 120 of all five cavities are connected together via connection means in the form of acommon control rod 128.Control rod 128 is slidably mounted withinhousing 100 to allow all fiveadjuster elements 120 to be slidably moved substantially simultaneously on actuation of the control rod. More particularly,control rod 128 is slidably mounted in a plurality of guide channels defined in an upper edge of the side walls of the housing.Figures 5a-5c illustrate a first position of theadjuster elements 120 andfigures 6a-6c illustrate a second position of theadjuster elements 120 following actuation ofcontrol rod 128 in use. This allows the frequency of all theprimary resonators 112 to be adjusted by a substantially equal amount substantially simultaneously, thereby creating an accurate and substantially reproducible tuning method for the filter. The provision of thesecondary resonator 118 in addition to theadjuster element 120 provides allowing a greater tunable frequency range and simpler mechanical implementation compared to the use of an adjuster element and a primary resonator alone as is used in the prior art. - Actuation of the
control 128 can be performed manually or can be performed automatically using for exampled one or more powered motors. In either case actuation ofcontrol 128 can be performed directly or remotely. -
Figure 7 illustrates how the frequency of the filter infigures 5a-6c can be adjusted on moving theadjuster elements 20 from the first to the second position. Lines 'A' and 'B' show the lowest and highest operating frequencies of the filter following bandwidth adjustment. Thus, it can be seen that the centre operating frequency of the filter can be adjusted using the described invention. - Referring to
figures 8a-8b , there is illustrated a further embodiment of the present invention in which the range of the bandwidth of the filter can be increased or decreased. This embodiment can be used and/or can be provided independently of the embodiments previously described or can be used and/or can be provided in combination with the previously described figures. - More particularly, a single cavity of a multiple cavity tuner is illustrated in
figures 8a-8b . Similar reference numbers have been used to denote similar features infigures 4a and4b . In addition tofirst adjuster element 20, a second conductive ordielectric adjuster element 200 is provided between theside wall 8 of the filter housing and thesecondary resonator 18. Provision of thesecond adjuster element 200 in the cavity allows the resonant frequency of thesecondary resonator 18 to be adjusted independently of theprimary resonator 12 by a sliding movement as indicated by thearrow 222. - As mentioned previously, a filter typically includes a plurality of cavities defined therein and each cavity typically contains a primary-secondary resonator pair and an adjustment element.
Figure 9a ,9b and9c show a similar filter to the one infigure 5a ,5b and5c with an additional secondtunable element 131 enabling the tuning adjustment of the resonant frequency of thesecondary resonator 130. - Each of the additional tunable elements are connected together via connection means in the form of a
common control rod 128.Control rod 128 is slidably mounted withinhousing 100 to allow all fiveadditional adjuster elements 131 to be slidably moved substantially simultaneously on actuation of the control rod. More particularly,control rod 128 is slidably mounted in a plurality of guide channels defined in an upper edge of the side walls of the housing.Figures 9a-9c illustrate a first position of theadjuster elements 131 andfigures 10a-10c illustrate a second position of theadjuster elements 131 following actuation ofcontrol rod 128 in use. This allows the frequency of all thesecondary resonators 130 to be adjusted by a substantially equal amount substantially simultaneously, thereby creating an accurate and substantially reproducible tuning method for the filter bandwidth and frequency.
Claims (15)
- A tunable filter, said tunable filter including a housing (4; 100) with two or more cavities (2; 102) defined therein, primary resonating means (12; 112) located in each of said cavities and each primary resonating means resonating at a first frequency, the primary resonating means in each of the two or more cavities of the filter are coupled together to form a required filter response, characterised in that said tunable filter further includes secondary resonating means (18; 118) associated therewith resonating at a second frequency different to the first frequency of said primary resonating means, said secondary resonating means arranged such that each secondary resonating means is coupled to its associated primary resonating means to form a primary-secondary resonator pair, and wherein the tunable filter includes adjustment means (20; 120) for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonating means.
- A tunable filter according to claim 1 wherein the secondary resonating means (18; 118) is located internally of the filter housing (4; 100) with the primary resonating means (12; 112).
- A tunable filter according to claim 1 wherein the secondary resonating means (18, 118) is located in the cavity of the primary resonating means (12, 112) to form the primary-secondary resonator pair.
- A tunable filter according to claim 1 wherein the secondary resonating means (18; 118) is located externally of the filter housing (4; 100) or cavity in which the primary resonating means (12; 112) is located.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) for adjusting two or more primary-secondary resonating pairs in the filter are connected together via connection means, such that the coupling within each primary-secondary resonating pair of the two or more primary-secondary resonating pairs can be adjusted substantially simultaneously.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) for adjusting two or more secondary resonating means (18; 118) are connected together via connection means, such that the resonating frequency of each secondary resonating means can be adjusted substantially simultaneously.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) for adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonating means (18; 188) are arranged such that each resonator pair and/or secondary resonator can be adjusted substantially independently of any other resonator pair and/or secondary resonating means in said filter.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) are adjusted manually.
- The tunable filter according to claim 5 wherein the adjustment means (20; 120) are driven by any or any combination of electrical, pneumatic, and/or mechanical means.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) includes one or more adjustment elements formed, at least in part, from conductive material.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) includes one or more adjustment elements formed, at least in part, from dielectric material.
- The tunable filter according to claim 1 wherein the adjustment means (20; 120) and/or connection means for connecting a number of adjustment means together are capable of undergoing rotatable, pivotable and/or slideable movement during the adjustment process.
- The tunable filter according to claim 11 wherein the one or more adjustment elements are engaged with the primary and/or secondary resonator means of a primary-secondary resonating pair (18; 118).
- The tunable filter according to claim 10 wherein the one or more adjustment elements are a spaced distance apart from the primary (12; 112) and/or secondary resonating means (18; 118) of a primary-secondary resonating pair.
- A method of adjusting the operating frequency and/or bandwidth of a tunable filter, said tunable filter including a housing (4; 100) with two or more cavities (2; 102) defined therein, primary resonating means (12; 112) located in each of said cavities and each primary resonating means resonating at a first frequency, the primary resonating means in each of the two or more cavities of the filter are coupled together to form a required filter response, characterised in that said tunable filter further includes secondary resonating means (18; 118) associated therewith resonating at a second frequency different to the first frequency of said primary resonating means, said secondary resonating means arranged such that each secondary resonating means is coupled to its associated primary resonating means to form a primary-secondary resonator pair, and wherein said method includes the step of adjusting the coupling within each primary and secondary resonator pair and/or the resonant frequency of the secondary resonating means.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0721361A GB0721361D0 (en) | 2007-10-30 | 2007-10-30 | Tunable filter |
PCT/GB2008/003645 WO2009056813A1 (en) | 2007-10-30 | 2008-10-27 | Tunable filter and method of use thereof |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2203953A1 EP2203953A1 (en) | 2010-07-07 |
EP2203953B1 true EP2203953B1 (en) | 2015-08-05 |
Family
ID=38834588
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08846190.0A Active EP2203953B1 (en) | 2007-10-30 | 2008-10-27 | Tunable filter and method of use thereof |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2203953B1 (en) |
GB (1) | GB0721361D0 (en) |
WO (1) | WO2009056813A1 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB201203833D0 (en) * | 2012-03-05 | 2012-04-18 | Filtronic Wireless Ltd | A tuneable filter |
CN102683773B (en) * | 2012-04-28 | 2014-07-09 | 华为技术有限公司 | Adjustable filter and duplexer comprising same |
EP2814112A1 (en) * | 2013-06-13 | 2014-12-17 | Alcatel Lucent | Resonant assembly |
EP2814111B1 (en) * | 2013-06-13 | 2020-03-18 | Alcatel Lucent | Resonant assembly |
DE102013020428A1 (en) * | 2013-12-05 | 2015-06-11 | Kathrein-Werke Kg | High frequency filter in coaxial design |
EP2894710B1 (en) * | 2014-01-10 | 2019-05-08 | Alcatel Lucent | Coaxial resonator filter |
US9979063B2 (en) * | 2016-02-12 | 2018-05-22 | Huawei Technologies Cananda Co., Ltd. | Rod-switched tunable filter |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5535560A (en) * | 1978-09-04 | 1980-03-12 | Matsushita Electric Ind Co Ltd | Coaxial type filter |
DE3906286A1 (en) * | 1989-02-28 | 1990-08-30 | Siemens Ag | Ceramic microwave filter having aperture-coupled ceramic resonators with steepened resonance curve |
GB2247125B (en) * | 1990-08-16 | 1995-01-11 | Technophone Ltd | Tunable bandpass filter |
US5841330A (en) * | 1995-03-23 | 1998-11-24 | Bartley Machines & Manufacturing | Series coupled filters where the first filter is a dielectric resonator filter with cross-coupling |
US6924718B2 (en) * | 2002-12-04 | 2005-08-02 | Rs Microwave Company | Coupling probe having an adjustable tuning conductor |
FI119207B (en) * | 2003-03-18 | 2008-08-29 | Filtronic Comtek Oy | Koaxialresonatorfilter |
FI20041546A (en) * | 2004-11-30 | 2006-05-31 | Filtronic Comtek Oy | Temperature compensated resonator |
-
2007
- 2007-10-30 GB GB0721361A patent/GB0721361D0/en not_active Ceased
-
2008
- 2008-10-27 WO PCT/GB2008/003645 patent/WO2009056813A1/en active Application Filing
- 2008-10-27 EP EP08846190.0A patent/EP2203953B1/en active Active
Also Published As
Publication number | Publication date |
---|---|
EP2203953A1 (en) | 2010-07-07 |
GB0721361D0 (en) | 2007-12-12 |
WO2009056813A9 (en) | 2009-10-08 |
WO2009056813A1 (en) | 2009-05-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2203953B1 (en) | Tunable filter and method of use thereof | |
US7180391B2 (en) | Resonator filter | |
US6833820B2 (en) | Tunable monopole antenna | |
EP2913884B1 (en) | Tunable band-pass filter | |
US6147577A (en) | Tunable ceramic filters | |
US6836198B2 (en) | Adjustable capacitive coupling structure | |
WO2006075439A1 (en) | Tunable filter, duplexer and communication apparatus | |
EP3104453A1 (en) | A resonator assembly and filter | |
WO2018069864A1 (en) | Tunable band-pass filter | |
KR102081950B1 (en) | High frequency filter and apparatus for tunning the same | |
US7796000B2 (en) | Filter coupled by conductive plates having curved surface | |
US6118356A (en) | Microwave cavity having a removable end wall | |
WO2010032023A1 (en) | Tuneable planar dielectric resonator | |
GB2571622A (en) | Tunable filter apparatus and method of use thereof | |
US8159314B1 (en) | Actively tuned filter | |
RU2709030C1 (en) | Band-stop filter | |
Naeem et al. | Design of compact dual‐mode dual‐band SIW filter with independent tuning capability | |
US6005452A (en) | Fixed tuneable loop | |
EP3349300B1 (en) | Channel filter with adjustable frequency | |
EP2814111B1 (en) | Resonant assembly | |
US9385409B2 (en) | Multi-mode resonator/filter comprised of first and second columnar central conductors disposed within a cylindrical exterior conductor | |
US11121445B2 (en) | Resonator for radio frequency signals | |
WO2023237183A1 (en) | Tunable resonator arrangement, tunable frequency filter and method of tuning thereof | |
WO2007013740A1 (en) | Filter coupled by conductive plates having curved surface | |
WO2019024082A1 (en) | Bandpass filters and associated methods. |
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 |
|
17P | Request for examination filed |
Effective date: 20100324 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA MK RS |
|
DAX | Request for extension of the european patent (deleted) | ||
17Q | First examination report despatched |
Effective date: 20130821 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
INTG | Intention to grant announced |
Effective date: 20150304 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: REF Ref document number: 741152 Country of ref document: AT Kind code of ref document: T Effective date: 20150815 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 602008039418 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 8 |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 741152 Country of ref document: AT Kind code of ref document: T Effective date: 20150805 |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG4D |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MP Effective date: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LV Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20151106 Ref country code: FI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: NO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20151105 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: SE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: PL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: PT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20151207 Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20151205 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CZ Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: DK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: SK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: EE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602008039418 Country of ref document: DE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: RO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: LU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20151027 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
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 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MC Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
26N | No opposition filed |
Effective date: 20160509 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: MM4A |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20151031 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20151031 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 9 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20151027 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BG Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: HU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO Effective date: 20081027 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CY Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 Ref country code: TR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20150805 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 10 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20231004 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: 20231004 Year of fee payment: 16 Ref country code: DE Payment date: 20231005 Year of fee payment: 16 |