Tunable filter systems, devices, and methods

Patent metadata

Field	Value
Publication number	US-9559659-B2
Application number	US-201414216331-A
Country	US
Kind code	B2
Filing date	Mar 17, 2014
Priority date	Mar 15, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

Systems, devices, and methods for tunable filters that are configured to support multiple frequency bands, such as within the field of cellular radio communication, can include a first resonator and a second resonator configured to block signals within one or more frequency ranges, and one or more coupling element connected to both the first resonator and the second resonator. The one or more coupling element can be configured to provide low insertion loss within a pass band.

First claim

What is claimed is:

1. A tunable filter comprising:
a first resonator and a second resonator connected between a first port and a second port, the first resonator and the second resonator being configured to resonate at a reject band frequency, wherein the first resonator and the second resonator are configured to block signals within the reject band frequency between the first port and the second port, and wherein the first resonator and the second resonator are tunable to define the reject band frequency; and
one or more coupling elements connected to both the first resonator and the second resonator and configured to define a pass band frequency that is different than the reject band frequency;
wherein the one or more coupling elements are configured to adjust a frequency at which a simultaneous conjugate match of impedances of the first resonator and of the second resonator is substantially achieved to provide low insertion loss within the pass band frequency.

2. The tunable filter of claim 1 , wherein the one or more coupling elements comprise one or more capacitors.

3. The tunable filter of claim 2 , wherein the one or more coupling elements comprise one or more inductors.

4. The tunable filter of claim 3 , wherein the one or more capacitors and the one or more inductors are connected in a series arrangement.

5. The tunable filter of claim 3 , wherein the one or more capacitors and the one or more inductors are connected in a parallel arrangement.

6. The tunable filter of claim 1 , wherein one or more of the first resonator, the second resonator, or the one or more coupling elements are electrically tunable.

7. The tunable filter of claim 6 , wherein the one or more of the first resonator, the second resonator, or the one or more coupling elements comprise a variable or switchable capacitor.

8. The tunable filter of claim 7 , wherein the variable or switchable capacitor comprises one or more of a ferroelectric, paraelectric, MEMS, or solid-state capacitor.

9. The tunable filter of claim 1 , wherein one or both of the first resonator or the second resonator comprises an inductor and a capacitor.

10. The tunable filter of claim 9 , wherein the inductor and the capacitor are connected in a parallel arrangement.

11. The tunable filter of claim 1 , wherein the one or more coupling elements are connected between a first port and a second port;
wherein the first resonator is connected between the first port and a ground; and

wherein the second resonator is connected between the second port and the ground.

12. The tunable filter of claim 1 , wherein the first resonator and the second resonator are connected together in a series arrangement between a first port and a second port; and
wherein the one or more coupling elements are connected to a node between the series connection of the first resonator and the second resonator and to a ground.

13. The tunable filter of claim 1 , wherein one or more of conductor traces or inductors of the first resonator and the second resonator are arranged in substantially orthogonal positions.

14. The tunable filter of claim 1 , wherein the first resonator, the second resonator, and the one or more coupling elements are configured such that loss in the pass band is less than 5 dB and blocking isolation in the first resonator and the second resonator is greater than 15 dB.

15. A method for adjusting a tunable filter, the method comprising:
connecting one or more coupling elements between a first resonator and a second resonator that are connected between a first port and a second port, wherein one or more of first resonator, the second resonator, or the one or more coupling elements are electrically tunable;
selectively adjusting a tuning setting of one or more of the first resonator or the second resonator to adjust a reject band frequency at which the first resonator and the second resonator are configured to resonate to block signals within the reject band frequency between the first port and the second port; and
selectively adjusting a tuning setting of the one or more coupling elements to adjust a pass band frequency defined by the one or more coupling elements such that a simultaneous conjugate match to a first impedance of the first resonator and to a second impedance of the second resonator is substantially achieved to provide low insertion loss within the pass band frequency.

16. The method of claim 15 , wherein selectively adjusting a tuning setting of one or more of the first resonator or the second resonator to block signals within the reject band frequency comprises selectively adjusting a tuning setting of one or more of the first resonator or the second resonator to provide blocking isolation in the first resonator and the second resonator greater than 15 dB.

17. The method of claim 15 , wherein selectively adjusting a tuning setting of one or more of the first resonator or the second resonator comprises varying an electric field or current to the first resonator or the second resonator.

18. The method of claim 15 , wherein selectively adjusting a tuning setting of the one or more coupling elements to provide low insertion loss within the pass band frequency comprises selectively adjusting a tuning setting of the one or more coupling elements to provide loss in the pass band is less than 5 dB.

19. The method of claim 15 , wherein selectively adjusting a tuning setting of one or more coupling elements comprises varying an electric field or current to the one or more coupling elements.

Assignees

• Wispry Inc

Inventors

• Bojer Jorgen

Classifications

• H03H7/0153 Primary

  Electrical filters; Controlling thereof · CPC title

• H03H2210/033

  Continuous · CPC title

• H03H2210/025

  Capacitor · CPC title

• H03H2210/012

  Centre frequency; Cut-off frequency · CPC title