WO1997023012A1 - Arrangement and method relating to filtering of signals - Google Patents
Arrangement and method relating to filtering of signals Download PDFInfo
- Publication number
- WO1997023012A1 WO1997023012A1 PCT/SE1996/001688 SE9601688W WO9723012A1 WO 1997023012 A1 WO1997023012 A1 WO 1997023012A1 SE 9601688 W SE9601688 W SE 9601688W WO 9723012 A1 WO9723012 A1 WO 9723012A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- resonator
- superconducting
- arrangement
- filter
- microstrip line
- Prior art date
Links
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
- H01P1/203—Strip line filters
- H01P1/20309—Strip line filters with dielectric resonator
Definitions
- the present invention relates to superconducting filter arrangements, particularly notch filters or band reject filters which comprise a superconducting dielectric resonator and a waveguide arrangement such as e.g. a microstrip line.
- notch filters or band reject filters are within communications systems.
- a particular application of such relates to multichannel microwave communications systems which operate in high frequency bands in which the size of the components is highly important.
- the invention also relates to a method for filtering signals incoming to a receiving arrangement in a multichannel communication system.
- EP-A-0 567 407 discloses super-conducting notch filters with a fixed frequency wherein half wavelength, high temperature superconducting microstrip resonators are parallel coupled to the main high temperature superconducting microstrip line.
- the substrates of the resonators have dielectric constants of about 10-25 at frequencies between 1-3 GHz.
- the length of the filters is then about 2-6 cm; the filters are thus very large and they are also expensive.
- tuneable (switchable) notch filters are required instead of fixed frequency notch filters e.g. in order to increase the flexibility of the system.
- US-A-4,834,498 shows a simple dielectric resonator. The resonator is passive and it is not itself tunable.
- WO 93/00720 a superconducting notch filter with a microstrip resonator which is not tunable itself is illustrated.
- optical means are used to provide tuning, which use semiconductor crystals in superconducting microstrip ring resonators coupled to the main superconducting microstrip.
- the dimensions of these arrangements are large and moreover the frequency tuning range is much too small.
- both these devices need additional tuning means with a separate biasing circuit. That makes the designs large as well as complex. Furthermore, the electrical performance of the filter is negatively affected therethrough and it is also as such not as high as would be desired. E.g. for frequencies of about 1-3 GHz the devices as disclosed in these documents would be much too large and they cannot for example be used for telecommunication purposes.
- microwave devices can be made smaller if high dielectric constant non-linear dielectric materials such as for example Strontium Titanate (STO) are plated with super-conductors such as e.g. Y-Ba-Cu-O (YBCO).
- STO Strontium Titanate
- super-conductors such as e.g. Y-Ba-Cu-O (YBCO).
- WO 94/13028 discloses the use of thin single crystalline dielectric films in combination with high temperature superconductors which as such however produce too high microwave losses and moreover such devices cannot be made small enough.
- a method for filtering signals incoming to for example receiving arrangements in a multichannel microwave communication system operating at high frequencies is needed throuh which intermittent and interfering signals can be blanked out in an efficiant and leliable manner.
- a superconducting notch filter arrangement which comprises a resonator arranged on a microstrip line wherein the resonator is a parallel-plate resonator with a chip of a non-linear dielectric material on which superconductors are arranged.
- the resonator is connected to connecting means of a microstrip line or a strip of the microstrip line in such a way that an ohmic contact is provided.
- a parallel-plate resonator it can be arranged on top of a microstrip line, coupling is provided and the dimensions can be reduced. No special bias network is needed and no additional tuning means.
- the arrangement is particularly electrically tuneable, still more particularly through the application of a DC biasing voltage to the non-linear dielectricum of which the dielectric constant can be changed.
- a DC voltage is applied to normal conductors which may be arranged on the superconductors arranged on the dielectricum of the resonator.
- Advantageously contact means also denoted coupling means, are arranged to provide for dielectrical contact between the resonator and the microstrip line.
- the contact means are formed by the central strip of the microstrip line.
- a resonator comprises a rectangular (or some other shape) chip which is so oriented in relation to the microstrip line that the magnetic field lines of the microstrip line and the resonator substantially coincide in such a way that maximum inductive coupling is produced.
- the inductive coupling is particularly controlled or given by the relation between the resonator and microstrip line. Even more particularly the strength of the inductive coupling is given by the width of the central microstrip. To obtain the desired strength of coupling, the width can thus be given the value which provides the desired coupling.
- At least a portion of the lower plate of the parallel-plate resonator and/or the microstrip connecting means, for example the central strip, has/have a first width that is smaller than a second width in order to provide an increased inductive coupling.
- the resonator is a dual mode resonator or even more particularly it is a multimode resonator.
- asymmetry may for example comprise a cut away corner or a protrusion or anything else.
- the resonator may be arranged so as to form an angle with the main microstrip line. The angle may for example take the value of approximately 45°.
- the waveguiding arrangement may comprise a coplanar waveguide.
- the coupling strength is controlled by or given by the width of the central strip and of the coplanar waveguide slots.
- the tuning is advantageously provided (which relates to all embodiments) through the application of a DC biasing voltage which may be applied between the upper plate of the resonator and the coupling means, e.g. the central strip of the microstrip line.
- the area of the resonator may have a size between approximately 1 mm 2 -1 cm 2 .
- these values are merely given for exemplifying reasons, the resonator may also have other proportions, smaller as well as somewhat bigger.
- a method for filtering signals incoming to for example a receiving arrangement of a multichannel communication system or similar comprises the steps of: arranging a filter on the input side of a receiving arrangement, which filter comprises a parallel-plate resonator comprising a non-linear dielectricum on which superconductor plates are arranged, which is arranged on a waveguide, e.g. a microstrip line.
- the resonator and the waveguide arrangement are connected electrically in series through the use of coupling means.
- the coupling strength is given by how the resonator and the coupling means are arranged in relation to each other.
- a DC biasing voltage is applied to the resonator and the coupling means for frequency tuning.
- the steps are carried out so that intermittent interfering signals can be blanked out.
- FIG 1 illustrates an example of a parallel-plate resonator
- FIG 2 schematically illustrates a first embodiment of a
- FIG 3 is a cross-section of the notch filter of Fig 2
- FIG 4 illustrates an equivalent circuit of the notch filter of
- FIG 5 is a diagram illustrating the temperature dependence of the central frequency of a particular notch filter
- FIG 6a schematically illustrates a cross-section of a second embodiment of a notch filter
- FIG 6b is a longitudinal cross-section of the lower plate of the resonator
- FIG 6c is a longitudinal cross-section of the central frequency
- FIG 7 illustrates an embodiment of a two-pole notch filter
- FIG 8 is a further embodiment relating to a two-pole notch
- FIG 9 schematically illustrates a coplanar waveguide notch
- a resonator is arranged on d waveguide arrangement.
- Fig 1 shows a first example of a parallel-plate resonator that can be used.
- the resonator 11 comprises a dielectrium 12 in the form of a rectangular chip of a non-linear dielectrium on both surfaces of which thin high temperature superconducting HTS films 13a, 13b are arranged.
- Magnetic coupling means or DC contact means are arranged in such a way that the filter rejection band and central frequency can be electrically controlled.
- the superconducting films or plates 13a, 13b may advantageously be partly or completely covered by normal conducting films 14, 14 for example of Au thus forming ohmic contacts for DC biasing.
- the dielectric material comprises a non-linear dielectric bulk material since for bulk material the microwave losses are lower and the dielectric constant is higher than for example for thin dielectric films. Through the use of a non-linear dielectric material, electrical controlling is enabled.
- the microwave losses of for example Strontium Titanate, hereinafter referred to as STO are close to minimum at the temperature of liquid nitrogen, N liq which is discussed in "Dielectric properties of single crystals of Al 2 O 3 , LaAlO 3 , NdGaO 3 , SrTiO 3 and MgO at cryogenic temperatures", by Krupka et al., in IEEE Trans. Microwave Theory Techn., 1994, Vol. 42, pp. 1886-1890.
- the dielectric constant of STO is about 2000 at the temperature of N liq and it is strongly dependent on temperature and on applied electric DC fields.
- the resonator may advantageously comprise a non-linear bulk dielectric material 12 e.g. by STO which is covered by HTS films of e.g. YBCO.
- STO non-linear bulk dielectric material
- HTS films e.g. YBCO.
- the microwave losses are very low.
- the superconducting films or plates 13a, 13b of the parallel-plate resonator are made slightly smaller than the dielectric chip 12 in order to account for mechanical tolerences and for the provision of an improved ability of controlling the resonant frequency.
- Fig 2 shows a first embodiment of a tuneable notch filter 10 according to the invention.
- the resonator 11 of Fig 1 is arranged on a waveguiding arrangement 15 in the form of a microstrip line.
- the resonator 11 is in this embodiment connected to or attached to the central strip 18 of the microstrip line 15 wherein said central strip 18 acts as the contact means or couplings means providing ohmic contact between the lower plate 13b of the parallel-plate resonator II and the microstrip line 15. No special bias network, no additional tuning means are required.
- the microstrip line 15 comprises a substrate e.g. of Al or any other known dielectricum for ⁇ w-strips.
- the ground plane 17 comprises e.g. Cu, Au or anything similar having normal conductivity. However, in a very advantageous embodiment the ground plane 17 and the central strip 18 comprise HTS films.
- the parallel-plate resonator chip 11 is so arranged in relation to the microstrip line 15 that the magnetic field lines of the microstrip 18 and the resonator 11 substantially coincide (c.f. Fig 3) thus ensuring a high degree of inductive coupling, or more precisely maximum inductive coupling.
- the width of the central microstrip 18 determines the coupling strength between the resonator 11 and the microstrip line 15 and thus the coupling strength can be controlled through choosing the appropriate width.
- the width can in advantageous embodiments be approximately in the range between 0,5-1 mm, but it can also have a smaller or larger width.
- Connection means 19, 19 are provided through which a DC biasing voltage can be applied between the microstrip and the upper plate 13a of the parallel-plate resonator 11. In this way electrical tuning is provided and the DC biasing voltage applied to the non-linear dielectric 12 changes the dielectric constant thereof and thus the resonant frequency of the parallel-plate resonator 11.
- One of the resonator plates is advantageously in mechanical or electrical contact with the main microstrip line.
- the main microstrip is advantageously used as a bias terminal for DC-biasing. This is in contrast to e.g. US-A-4, 835, 498 and WO-A-93/00720, wherein the resonator could not be in contact with a main microstrip line.
- Fig 3 is a cross-sectional view of the notch filter 10 as illustrated in Fig 2. It shows how the resonator 11 is arranged on the central microstrip 18 of the microstrip line 15. H denotes the magnetic field lines of the resonator and of the microstrip line. As discussed above, the magnetic field lines substantially coincide thus providing a high degree of coupling between the resonator 11 and the microstrip line 15.
- Fig 4 schematically shows an equivalent circuit of the notch filter 10 as illustrated in Figs 2 and 3 above.
- Z 0 indicates the impedance of the microstrip whereas the dashed line is the circuit representation of the resonator 11.
- the resonator is a STO resonator plated with YBCO films as discussed above and the dielectricum in this particular embodiment has the dimensions 2.5 ⁇ 2.5 ⁇ 0.5 mm 3 .
- the waveguide arrangement comprises a 50 Ohm copper microstrip on a 0.5 mm aluminium substrate. Of course this is only one example and other materials car be used, the dimensions can be different etc.
- Fig 5 shows a diagram of the temperature dependence of the center frequency of a notch filter having the above mentioned dimensions and no biasing voltage is applied.
- Fig 6a an alternate embodiment of a notch filter 20 is illustrated.
- a resonator 21, also in this case comprising a non-linear dielectric bulk material 22 plated with thin superconducting films 23a, 23b which in turn are covered by normal conducting layers 24a, 24b for example from Au, is arranged on a microstrip line 25.
- the microstrip line 25 comprises a substrate for example of Al. On one of its surfaces e.g.
- a copper microstrip 27 is arranged whereas on the other side of the substrate a central microstrip 28 is arranged.
- the central microstrip 28 forms the contact means or the connection means between the resonator 21 and the microstrip line 25.
- an inductive leading is provided through a second section 23b 2 of the lower resonator plate 23b having a smaller width then a first section 23b 1 .
- the microstrip 28 is provided with a second section 28b the width of which is smaller than the width of the first section 28a.
- Figs 6b and 6c are longitudinal views seen from above of the lower plate of the resonator and the microstrip respectively, the arrangement whicn is illustrated in Fig 6a indicating the portions 23b 2 and 28b each having a smaller width.
- Fig 7 very schematically illustrates a two-pole notch filter.
- a resonator 31 (e.g. as discussed under reference to previous embodiments) is arranged on a microstrip line 35.
- One ol the corners of the upper superconducting film 33a is cut away; thus producing an asymmetry in the resontor. 32 indicates the dielectricum. Since one of the corners of the upper superconducting film 33a is cut off, it is achieved that the resonator 31 can operate in a dual mode. Thus the width of the rejection band and its skirts can be adapted to the current needs.
- Fig 8 shows still a further embodiment of a two-pole notch filter
- a resonator 41 (c.f. above) is arranged on the microstrip line 45 in such a way that it forms an angle with the microstrip line.
- the parallel-plate resonator 41 forms an angle of 45° with the main microstrip. Since an asymmetry is introduced, the resonator also in this case operates in dual mode. The angle does of course not have to be 45° but it can take a higher as well as a lower value; in principle any angle but 90°.
- the invention can in principle also be applied to multimode filters for example operating in three modes. Such an arrangement is illustrated in the at the same time filed Swedish Patent Application "Arrangements and methods relating to multiplexing/switching" having the same applicant, the subject matter of which is incorporated herein by reference.
- Fig 9 schematically illustrates yet another embodiment comprising a coplanar waveguide (CPW) tuneable notch filter 50, which also can be dual mode operating.
- a superconducting parallel-plate resonator 51 is attached to the central strip 58 of a coplanar waveguide (CPW) 55 in order to provide for a higher degree of design flexibility.
- the coupling strength and the wave impedance of the coplanar waveguide 55 is given by the width of the central strip 58 and the slots 59 of the CPW.
- the width of the central strip can take the values as discussed earlier under reference to Fig. 2 (which also applies to the other embodiments) but in this case the flexibility is even higher.
- the width is generally chosen depending on the substrate thickness.
- the invention is not limited to the shown embodiments but other materials can be used, for example it does not have to be a bulk dielectric material, in some cases also thin dielectric materials can be used.
- the form of the resonator can be of different kinds as well as the waveguiding means can take a number of different forms and it does not necessarily have to be a central strip of a microstrip line that forms the coupling means.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP09522713A JP2000502231A (en) | 1995-12-19 | 1996-12-18 | Apparatus for filtering a signal and associated method |
DE69614142T DE69614142T2 (en) | 1995-12-19 | 1996-12-18 | ARRANGEMENT AND METHOD FOR FILTERING SIGNALS |
EP96943451A EP0868762B1 (en) | 1995-12-19 | 1996-12-18 | Arrangement and method relating to filtering of signals |
US09/100,168 US6111485A (en) | 1995-12-19 | 1998-06-18 | Arrangement and method relating to filtering of signals |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9504530-8 | 1995-12-19 | ||
SE9504530A SE507751C2 (en) | 1995-12-19 | 1995-12-19 | Device and method of filtering signals |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/100,168 Continuation US6111485A (en) | 1995-12-19 | 1998-06-18 | Arrangement and method relating to filtering of signals |
Publications (1)
Publication Number | Publication Date |
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WO1997023012A1 true WO1997023012A1 (en) | 1997-06-26 |
Family
ID=20400636
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1996/001688 WO1997023012A1 (en) | 1995-12-19 | 1996-12-18 | Arrangement and method relating to filtering of signals |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0868762B1 (en) |
JP (1) | JP2000502231A (en) |
DE (1) | DE69614142T2 (en) |
ES (1) | ES2159774T3 (en) |
SE (1) | SE507751C2 (en) |
WO (1) | WO1997023012A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005091316A1 (en) * | 2004-02-27 | 2005-09-29 | Centre National De La Recherche Scientifique (Cnrs) | Tunable-inductance thin-layered superconductor components, method for the production thereof and devices including said components |
US7394334B2 (en) | 2005-01-11 | 2008-07-01 | Murata Manufacturing Co., Ltd. | Dielectric resonance apparatus, oscillation apparatus, and transmission/reception apparatus |
US7587229B2 (en) | 2006-03-30 | 2009-09-08 | Fujitsu Limited | Superconducting tunable filter having a patch resonator pattern tuned by a variable dielectric constant top plate |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4835498A (en) * | 1987-06-09 | 1989-05-30 | Thomson-Csf | Tunable microwave filtering device with dielectric resonator, and applications |
WO1993000720A1 (en) * | 1991-06-24 | 1993-01-07 | Superconductor Technologies Inc. | Active superconductive devices |
EP0567407A1 (en) * | 1992-04-22 | 1993-10-27 | Sumitomo Electric Industries, Ltd. | Microwave component of oxide superconducter material |
US5496796A (en) * | 1994-09-20 | 1996-03-05 | Das; Satyendranath | High Tc superconducting band reject ferroelectric filter (TFF) |
-
1995
- 1995-12-19 SE SE9504530A patent/SE507751C2/en not_active IP Right Cessation
-
1996
- 1996-12-18 EP EP96943451A patent/EP0868762B1/en not_active Expired - Lifetime
- 1996-12-18 DE DE69614142T patent/DE69614142T2/en not_active Expired - Fee Related
- 1996-12-18 ES ES96943451T patent/ES2159774T3/en not_active Expired - Lifetime
- 1996-12-18 JP JP09522713A patent/JP2000502231A/en active Pending
- 1996-12-18 WO PCT/SE1996/001688 patent/WO1997023012A1/en active IP Right Grant
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4835498A (en) * | 1987-06-09 | 1989-05-30 | Thomson-Csf | Tunable microwave filtering device with dielectric resonator, and applications |
WO1993000720A1 (en) * | 1991-06-24 | 1993-01-07 | Superconductor Technologies Inc. | Active superconductive devices |
EP0567407A1 (en) * | 1992-04-22 | 1993-10-27 | Sumitomo Electric Industries, Ltd. | Microwave component of oxide superconducter material |
US5496796A (en) * | 1994-09-20 | 1996-03-05 | Das; Satyendranath | High Tc superconducting band reject ferroelectric filter (TFF) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005091316A1 (en) * | 2004-02-27 | 2005-09-29 | Centre National De La Recherche Scientifique (Cnrs) | Tunable-inductance thin-layered superconductor components, method for the production thereof and devices including said components |
US7633356B2 (en) | 2004-02-27 | 2009-12-15 | Centre National De La Recherche Scientifique | Tunable-inductance thin-layered superconductor components, method for the production thereof and devices including said components |
US7394334B2 (en) | 2005-01-11 | 2008-07-01 | Murata Manufacturing Co., Ltd. | Dielectric resonance apparatus, oscillation apparatus, and transmission/reception apparatus |
US7587229B2 (en) | 2006-03-30 | 2009-09-08 | Fujitsu Limited | Superconducting tunable filter having a patch resonator pattern tuned by a variable dielectric constant top plate |
Also Published As
Publication number | Publication date |
---|---|
SE507751C2 (en) | 1998-07-13 |
DE69614142D1 (en) | 2001-08-30 |
SE9504530D0 (en) | 1995-12-19 |
SE9504530L (en) | 1997-06-20 |
ES2159774T3 (en) | 2001-10-16 |
DE69614142T2 (en) | 2001-11-15 |
EP0868762B1 (en) | 2001-07-25 |
EP0868762A1 (en) | 1998-10-07 |
JP2000502231A (en) | 2000-02-22 |
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