Arrangement and method relating to filtering of signals

• US 6,111,485 A
• Filed: 06/18/1998
• Issued: 08/29/2000
• Est. Priority Date: 12/19/1995
• Status: Expired due to Fees

• Current Assignee: Siebe Climate Controls Italia SpA, Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Linner, Peter, Gevorgian, Spartak, Carlsson, Erik, Wikborg, Erland, Kollberg, Erik
• Primary Examiner(s): Bettendorf, Justin P.
• Application Number:
  US09/100,168
• Time in Patent Office: 803 Days
• Field of Search: 333/995, 333/235, 333/219, 333/205, 505/210, 505/700, 505/701, 505/866
• US Class Current: 333/99.00S
• CPC Class Codes: H01P 1/20309 with dielectric resonator
• CPC Class Codes: Y10S 505/701 Coated or thin film device, i.e. active or passive

Abstract

A superconducting notch or band reject filter arrangement includes a superconducting dielectric resonator and a waveguide arrangement including a microstrip line to which the resonator is connected. The resonator is a parallel-plate resonator with a chip of a non-linear dielectric material device on which superconductors are arranged and the waveguide arrangement includes a contact device or a coupling device, the resonator being connected to the contact device of the waveguide arrangement in such a way that electric contact is provided, and the filter arrangement is frequency tuneable. Through the arrangement, the insertion losses are low.

Claims

1. Superconducting filter arrangement comprising a superconducting dielectric resonator and a waveguide arrangement comprising a microstrip line to which the resonator is connected, wherein the resonator is a finite parallel-plate resonator made of a non-linear dielectric material that has a high dielectric constant on which superconducting plates are arranged, wherein the resonator has finite extensions and the waveguide arrangement comprises a microstrip line magnetically coupled to one of the plates of the resonator via contact means, the resonator being connected to said contact means of the waveguide arrangement in such a way that electric contact is provided and the filter arrangement is frequency tunable.

2. Superconducting filter arrangement according to claim 1, wherein the filter arrangement is electrically tunable.

3. Superconducting filter arrangement according to claim 2, wherein a DC biasing voltage, via connection means, is directly or indirectly applied to plates of the non-linear dielectric material to change the dielectric constant thereof.

4. Superconducting filter arrangement according to claim 3, wherein conductors are arranged on the resonator outer sides.

5. Superconducting filter according to claim 1, wherein one of the resonator plates is electrically connected or magnetically coupled to the microstrip line.

6. Superconducting filter arrangement according to claim 1, wherein the contact means comprises a central strip of the microstrip line, and the resonator is connected to said central strip.

7. Superconducting filter arrangement according to claim 1, wherein the parallel-plate resonator comprises a substantially rectangular chip.

8. Superconducting filter arrangement according to claim 7, wherein the resonator chip is so oriented in relation to the microstrip line that maximum inductive coupling is achieved.

9. Superconducting filter arrangement according to claim 8, wherein the resonator chip is so oriented in relation to the microstrip line that the magnetic field lines of the microstrip and the resonators substantially coincide.

10. Superconducting filter arrangement according to claim 1, wherein the inductive coupling between the resonator and the microstrip line is given by the relation between the resonator and the microstrip and by the relation between the physical dimensions thereof.

11. Superconducting filter arrangement according to claim 10, wherein the strength of the inductive coupling is determined by the width of the contact means.

12. Superconducting filter arrangement according to claim 1, wherein in order to increase the inductive coupling between the resonator and microstrip line, the lower plate of the parallel-plate resonator or microstrip connecting means each comprises a second portion having a width that is smaller than that of a first width portion, respectively.

13. Superconducting filter arrangement according to claim 1, wherein the resonator is a dual mode operating resonator, and the filter arrangement comprises a two-pole filter.

14. Superconducting filter arrangement according to claim 13, wherein the resonator comprises an asymmetry to provide the dual mode operation.

15. Superconducting notch filter arrangement according to claim 14, wherein the asymmetry comprises a cut-away corner of a plate of the resonator, a protruding portion of the resonator.

16. Superconducting filter arrangement according to claim 13, wherein the resonator is arranged to form an angle with the main microstrip line.

17. Superconducting filter arrangement according to claim 16, wherein the resonator forms an angle of about 45°

with the main microstrip line.

18. Superconducting filter arrangement according to claim 1, wherein the waveguide arrangement is a coplanar waveguide.

19. Superconducting filter arrangement according to claim 18, wherein coupling strength between the resonator and the coplanar waveguide is given by the width of the central strip and of the slots of the coplanar waveguide.

20. Superconducting filter arrangement according claim 1, wherein a DC-biasing voltage is applied via connection means between the upper plate of the resonator and the coupling means.

21. The superconducting filter arrangement according to claim 1, wherein said filter arrangement is used for filtering signals incoming to a receiving arrangement in a multichannel communications system to prevent interfering signals from being received in the receiving arrangement.

22. Superconducting filter for use in multichannel communications systems operating in high frequency bands comprising a waveguide arrangement and at least one resonator, wherein the resonator is a parallel-plate resonator comprising a non-linear dielectric material on which superconducting plates are arranged, and the waveguide arrangement comprises a microstrip line comprising contact means or coupling means, the resonator being so arranged in relation to the waveguide arrangement that a series resonant circuit is provided thus forming the filter, and connecting means are provided through which the filter can be frequency tuned.

23. Filter according to claim 22, wherein a DC-biasing voltage is applied via the connecting means.

24. Filter according to claim 22, wherein the microstrip line comprises a main microstrip line and a central microstrip forming said coupling means.

25. Filter according to claim 22, wherein the resonator comprises a non-linear dielectric bulk material plated with the superconducting plates, comprising high temperature super conductors.

26. Filter according to anyone of claim 22, wherein the resonator is a dual mode or a multimode resonator.

27. Filter according to claim 22, said filter comprising a two-pole notch filter.

28. Filter according to claim 22, wherein the resonator comprises a chip having an area of approximately between 1 mm² -1 cm² at frequencies of about 0.1-0.2 GHz.

29. Method for filtering signals incoming to a receiving arrangement in a multichannel communications system comprising the steps of:

arranging a filter on an input side of the receiving arrangement, wherein said filter comprises a finite parallel plate resonator made of a non-linear dielectric material that has a high dielectric constant on which superconducting plates are arranged and which is arranged on a waveguide arrangement, the resonator having finite extensions contact means being provided between said resonator and said waveguide arrangement, to provide a coupling in series of the resonator and the microstrip line,

arranging the resonator and the coupling means in relation to each other so that the needed coupling strength is provided, and

applying a DC-biasing voltage between the resonator and the contact means for frequency tuning, so that interfering signals are not received in the receiving arrangement.

30. Method according to claim 29, comprising the step of giving the filter the desired coupling strength through giving the contact means or coupling means such dimensions in relation to the resonator that the desired coupling strength is obtained and the resonator comprises a non-linear dielectric bulk material plated with HTS-films.