System and method for a radio frequency filter

Patent metadata

Field	Value
Publication number	US-10840887-B2
Application number	US-201816210610-A
Country	US
Kind code	B2
Filing date	Dec 5, 2018
Priority date	Dec 7, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

In accordance with an embodiment, a method of operating an RF system includes filtering a wideband RF signal using an adjustable center frequency bandpass filter to produce a filtered RF signal; amplifying the filtered RF signal to produce an amplified RF signal; and band stop filtering the amplified RF signal to produce a band stopped RF signal.

First claim

What is claimed is:

1. A method of operating an RF system, the method comprising:
filtering a wideband RF signal using an adjustable center frequency bandpass filter to produce a filtered RF signal;
amplifying the filtered RF signal to produce an amplified RF signal; and
band stop filtering the amplified RF signal to produce a band stopped RF signal,
wherein the adjustable center frequency bandpass filter has an order of three or lower.

2. The method of claim 1 , wherein a passband of the adjustable center frequency bandpass filter encompasses a plurality of RF bands of the wideband RF signal.

3. The method of claim 1 , wherein band stop filtering comprises using a tunable band stop filter, and the method further comprises adjusting a center frequency of the tunable band stop filter.

4. The method of claim 1 , wherein band stop filtering the amplified RF signal comprises using a notch filter.

5. The method of claim 4 , wherein the notch filter comprises a tunable acoustic filter.

6. A method of operating an RF system, the method comprising:
band stop filtering a wideband RF signal to produce a band stopped RF signal;
amplifying the band stopped RF signal to produce an amplified RF signal; and
filtering the amplified RF signal using an adjustable center frequency bandpass filter to produce a filtered RF signal,
wherein the adjustable center frequency bandpass filter has an order of three or lower.

7. The method of claim 6 , wherein a passband of the adjustable center frequency bandpass filter encompasses a plurality of RF bands of the wideband RF signal.

8. The method of claim 6 , wherein band stop filtering comprises using a tunable band stop filter, and the method further comprises adjusting a center frequency of the tunable band stop filter.

9. The method of claim 8 , wherein the wideband RF signal comprises an interfering signal at a first interfering frequency, and adjusting the frequency of the tunable band stop filter comprises adjusting the center frequency to first interfering frequency.

10. The method of claim 6 , wherein band stop filtering the amplified RF signal comprises using a notch filter.

11. An RF system comprising:
an adjustable center frequency bandpass filter configured to receive a wideband RF signal;
an amplifier having an input coupled to an output of the adjustable center frequency bandpass filter; and
a band stop filter having an input coupled to an output of the amplifier,
wherein the adjustable center frequency bandpass filter has an order of three or lower.

12. The RF system of claim 11 , wherein the adjustable center frequency bandpass filter has an order of 2.5.

13. The RF system of claim 11 , wherein the amplifier comprises a low noise amplifier (LNA).

14. The RF system of claim 13 , wherein the LNA comprises a tunable bandpass input matching circuit.

15. The RF system of claim 11 , wherein the band stop filter comprises a tunable band stop filter.

16. The RF system of claim 11 , wherein the adjustable center frequency bandpass filter comprises a plurality of selectable bandpass filters.

17. The RF system of claim 11 , wherein the adjustable center frequency bandpass filter comprises a continuously tunable bandpass filter.

18. The RF system of claim 17 , wherein the continuously tunable bandpass filter comprises a tunable acoustic filter.

19. The RF system of claim 11 , wherein the band stop filter comprises a notch filter.

20. The RF system of claim 19 , wherein the notch filter comprises a tunable acoustic filter.

21. The RF system of claim 11 , further comprising an antenna coupled to an input of the adjustable center frequency bandpass filter.

22. An RF system comprising:
a band stop filter configured to receive a wideband RF signal;
an amplifier having an input coupled to an output of the band stop filter; and
an adjustable center frequency bandpass filter having an input coupled to an output of the amplifier,
wherein the adjustable center frequency bandpass filter has an order of three or lower.

23. The RF system of claim 22 , wherein the adjustable center frequency bandpass filter has an order of 2.5.

24. The RF system of claim 22 , wherein the amplifier comprises a low noise amplifier (LNA).

25. The RF system of claim 24 , wherein the LNA comprises a tunable bandpass input matching circuit.

26. The RF system of claim 22 , wherein the band stop filter comprises a tunable band stop filter.

27. The RF system of claim 22 , wherein the adjustable center frequency bandpass filter comprises a plurality of selectable bandpass filters.

28. The RF system of claim 22 , wherein the adjustable center frequency bandpass filter comprises a continuously tunable bandpass filter.

29. The RF system of claim 28 , wherein the continuously tunable bandpass filter comprises a tunable acoustic filter.

30. The RF system of claim 22 , wherein band stop filter comprises a notch filter.

31. The RF system of claim 30 , wherein the notch filter comprises a tunable acoustic filter.

32. The RF system of claim 22 , further comprising an antenna coupled to an input of the adjustable center frequency bandpass filter.

33. The method of claim 1 , wherein the adjustable center frequency bandpass filter has an order of 2.5.

34. The method of claim 6 , wherein the adjustable center frequency bandpass filter has an order of 2.5.

Assignees

• Infineon Technologies Ag

Inventors

• Schmalzl Stefan Helmut
• Pfann Peter
• Bauder Ruediger
• Timme Hans-Joerg

Classifications

• H03H9/131

  consisting of a multilayered structure · CPC title

• H03H9/205

  having multiple resonators (crystal tuning forks H03H9/21) · CPC title

• H03H7/0161

  Bandpass filters (H03H7/12 takes precedence) · CPC title

• H03H7/0115 Primary

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H03H7/12

  Bandpass or bandstop filters with adjustable bandwidth and fixed centre frequency (H03H7/09 takes precedence) · CPC title