Acoustically coupled resonator notch and bandpass filters

Patent metadata

Field	Value
Publication number	US-11057018-B2
Application number	US-201816210812-A
Country	US
Kind code	B2
Filing date	Dec 5, 2018
Priority date	Dec 7, 2017
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A notch filter includes a first inductor coupled between an input node and an output node, a dual-resonator structure coupled between the input node and the output node, and a second inductor coupled between the dual-resonator structure and ground, and a bandpass filter includes a capacitor coupled between an input node and an output node, and a dual-resonator structure coupled between the input node, the output node, and ground.

First claim

What is claimed is:

1. A tunable notch filter comprising:
a first inductor having a first end directly coupled to an input node and a second end directly coupled to an output node;
a tunable resonator structure having a first end coupled between the input node and a second end coupled to the output node;
a second inductor coupled between an internal node of the tunable resonator structure and ground,
wherein the tunable resonator structure comprises a stacked crystal filter.

2. The tunable notch filter of claim 1 , wherein the tunable resonator structure comprises a tuning circuit.

3. The tunable notch filter of claim 2 , wherein the tuning circuit comprises a varactor coupled to a third inductor.

4. The tunable notch filter of claim 1 , wherein the tunable resonator structure comprises an additional stacked crystal filter.

5. The tunable notch filter of claim 1 , wherein the stacked crystal filter comprises at least one piezoelectric layer.

6. The tunable notch filter of claim 1 , wherein the stacked crystal filter comprises at least one coupling layer.

7. A tunable notch filter comprising:
a first inductor having a first end directly coupled to an input node and a second end directly coupled to an output node;
a tunable resonator structure having a first end coupled between the input node and a second end coupled to the output node;
a second inductor coupled between an internal node of the tunable resonator structure and ground,
wherein the tunable resonator structure comprises a coupled resonator filter.

8. The tunable notch filter of claim 7 , wherein the tunable resonator structure comprises a tuning circuit.

9. The tunable notch filter of claim 8 , wherein the tuning circuit comprises a varactor coupled to a third inductor.

10. The tunable notch filter of claim 7 , wherein the tunable resonator structure comprises an additional coupled resonator filter.

11. The tunable notch filter of claim 7 , wherein the coupled resonator filter comprises at least one piezoelectric layer.

12. The tunable notch filter of claim 7 , wherein the coupled resonator filter comprises at least one coupling layer.

13. A tunable notch filter comprising:
a first inductor having a first end directly coupled to an input node and a second end directly coupled to an output node;
a tunable resonator structure having a first end coupled between the input node and a second end coupled to the output node;
a second inductor coupled between an internal node of the tunable resonator structure and ground,
wherein the tunable resonator structure comprises a film bulk acoustic resonator.

14. The tunable notch filter of claim 13 , wherein the tunable resonator structure comprises a tuning circuit.

15. The tunable notch filter of claim 14 , wherein the tuning circuit comprises a varactor coupled to a third inductor.

16. The tunable notch filter of claim 13 , wherein the tunable resonator structure comprises an additional film bulk acoustic resonator.

17. The tunable notch filter of claim 13 , wherein the film bulk acoustic resonator comprises at least one piezoelectric layer.

18. The tunable notch filter of claim 13 , wherein the film bulk acoustic resonator comprises at least one coupling layer.

Assignees

• Infineon Technologies Ag

Inventors

• Timme Hans-Joerg
• Bauder Ruediger
• Bogner Andreas

Classifications

• H03H9/205

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

• H03H9/131

  consisting of a multilayered structure · CPC title

• H03H7/12

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