Granted Patent B2

US 8,063,714 · App. 12/959,237 · Granted Nov 22, 2011

Abstract

Claims (44)

1. A radio frequency (RF) filter, comprising:

a signal transmission path having an input and an output;

a plurality of resonant elements disposed along the signal transmission path between the input and the output; and

at least one non-resonant element coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to at least one resonant frequency of the respective resonant elements, and at least one sub-band between the transmission zeroes, wherein the non-resonant elements have susceptance values that locate at least one reflection zero within the at least one stop band, wherein a passband is created in the at least one sub-band.

2. The RF filter of claim 1 , wherein each of the transmission zeroes corresponds to a resonant frequency of the respective resonant element.

3. The RF filter of claim 1 , wherein a resonant frequency of each of the respective resonant elements corresponds to one of the transmission zeroes.

4. The RF filter of claim 1 , wherein the at least one sub-band comprises a plurality of sub-bands.

5. The RF filter of claim 1 , wherein the at least one reflection zero comprises a plurality of reflection zeroes.

6. The RF filter of claim 1 , wherein the at least one non-resonant element comprises a plurality of non-resonant elements.

7. The RF filter of claim 1 , wherein the at least one non-resonant element is a capacitor.

8. The RF filter of claim 1 , wherein the at least one non-resonant element is an inductor.

9. The RF filter of claim 1 , wherein each of the resonant elements comprises a thin-film lumped element structure.

10. The RF filter of claim 9 , wherein the thin-film lumped element structure comprises a high temperature superconductor (HTS).

11. The RF filter of claim 1 , wherein at least one of the resonant elements is an acoustic resonator.

12. The RF filter of claim 11 , wherein the acoustic resonator is a surface acoustic wave (SAW) resonator.

13. The RF filter of claim 11 , wherein the acoustic resonator is a bulk acoustic resonator.

14. The RF filter of claim 13 , wherein the bulk acoustic resonator is a film bulk acoustic resonator (FBAR).

15. The RF filter of claim 11 , wherein the acoustic resonator is a microelectromechanical system (MEMS) resonator.

16. The RF filter of claim 1 , further comprising a controller configured for adjusting the at least one non-resonant element to displace the at least one reflection zero within a desired frequency range.

17. The RF filter of claim 16 , wherein the controller is an electrical controller.

18. A radio frequency (RF) filter, comprising:

a signal transmission path having an input and an output;

a plurality of nodes disposed along the signal transmission path;

a plurality of resonant branches respectively extending from the nodes;

at least one non-resonant branch extending from at least one of the nodes;

a plurality of resonant elements respectively coupled to the resonant branches;

at least one non-resonant element respectively coupled to the at least one non-resonant branch;

a plurality of transmission zeroes corresponding to resonant frequencies of the resonant elements; and

at least one reflection zero formed between the transmission zeroes to create a pass band.

19. The RF filter of claim 18 , wherein the at least one non-resonant element comprises at least one variable non-resonant element for selectively displacing the at least one reflection zero relative to the transmission zeroes.

20. The RF filter of claim 18 , wherein plurality of transmission zeroes comprises more than two transmission zeroes.

21. The RF filter of claim 18 , wherein the at least one reflection zero comprises a plurality of reflection zeroes.

22. The RF filter of claim 18 , wherein the at least one non-resonant branch comprises a plurality of non-resonant branches, and wherein the at least one non-resonant element comprises a plurality of non-resonant elements.

23. The RF filter of claim 18 , wherein the at least one non-resonant element is a capacitor.

24. The RF filter of claim 18 , wherein the at least one non-resonant element is an inductor.

25. The RF filter of claim 18 , wherein each of the resonant elements comprises a thin-film lumped element structure.

26. The RF filter of claim 25 , wherein the thin-film lumped element structure comprises a high temperature superconductor (HTS).

27. The RF filter of claim 18 , wherein at least one of the resonant elements is an acoustic resonator.

28. The RF filter of claim 27 , wherein the acoustic resonator is a surface acoustic wave (SAW).

29. The RF filter of claim 27 , wherein the acoustic resonator is a bulk acoustic resonator.

30. The RF filter of claim 29 , wherein the bulk acoustic resonator is a film bulk acoustic resonator (FBAR).

31. The RF filter of claim 27 , wherein the acoustic resonator is a microelectromechanical system (MEMS) resonator.

32. The RF filter of claim 18 , further comprising a controller configured for adjusting the at least one non-resonant element to displace the at least one reflection zero within a desired frequency range.

33. The RF filter of claim 32 , wherein the controller is an electrical controller.

Assignments (7)