MICROWAVE ACOUSTIC WAVE FILTERS

• US 20140266510A1
• Filed: 07/02/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Resonant Inc. (Murata Manufacturing Co Limited)
• Inventors: Silver, Richard N., Raihn, Kurt F., Fenzi, Neal O., Hammond, Robert B.
• Granted Patent: US 9,325,294 B2
• Time in Patent Office: Days
• US Class Current: 333/186
• CPC Class Codes: G06F 30/36 Circuit design at the analogue level
• CPC Class Codes: H03H 2260/00 Theory relating to impedance networks
• CPC Class Codes: H03H 9/25 Constructional features of resonators using surface acoustic waves devices for manipulating acoustic surface waves in general G10K11/36
• CPC Class Codes: H03H 9/462 Microelectro-mechanical filters
• CPC Class Codes: H03H 9/465 in combination with other electronic elements
• CPC Class Codes: H03H 9/542 including passive elements H03H9/545 takes precedence
• CPC Class Codes: H03H 9/568 consisting of a ladder configuration
• CPC Class Codes: H03H 9/605 consisting of a ladder configuration
• CPC Class Codes: H03H 9/64 using surface acoustic waves
• CPC Class Codes: H03H 9/6483 Ladder SAW filters

Abstract

An acoustic microwave filter comprises an input and an output, and a plurality of acoustic resonators coupled between the input and the output. The difference between the lowest resonant frequency and the highest resonant frequency of a plurality of resonators in the filter is at least 1.25 times the frequency separation of the resonator with the highest resonant frequency in the plurality of resonators. Another acoustic microwave filter comprises an input and an output, and a plurality of acoustic resonators coupled between the input and the output to form a passband. The frequency difference between a local minimum or a local maximum of a return loss magnitude of the acoustic microwave filter and the edge of the passband is at least once the frequency separation of the resonator with the highest resonant frequency.

Claims

1-22. -22. (canceled)

23. An acoustic microwave filter, comprising:

an input and an output; and

a plurality of acoustic resonators coupled between the input and the output, wherein the difference between the lowest resonant frequency and the highest resonant frequency of a plurality of resonators in the filter is at least 1.25 times the frequency separation of the resonator with the highest resonant frequency in the plurality of resonators.

24. The acoustic microwave filter of claim 23, wherein the difference between the lowest resonant frequency and the highest resonant frequency of a plurality of resonators in the final filter circuit design is at least two times the frequency separation of the resonator with the highest resonant frequency in the plurality of resonators.

25. The acoustic microwave filter of claim 23, wherein the plurality of resonators comprises at least two in-line resonators and/or at least two in-shunt resonators.

26. The acoustic microwave filter of claim 23, wherein the plurality of resonators comprises at least one paired in-line resonator and in-shunt resonator.

27. The acoustic microwave filter of claim 23, wherein each of the plurality of resonators is one of a surface acoustic wave (SAW) resonator, a bulk acoustic wave (BAW) resonator, a film bulk acoustic resonator (FBAR), and a microelectromechanical system (MEMS) resonator.

28. An acoustic microwave filter, comprising:

an input and an output; and

a plurality of acoustic resonators coupled between the input and the output to form a passband, wherein the frequency difference between a local minimum or a local maximum of a return loss magnitude of the acoustic microwave filter and the edge of the passband is at least once the frequency separation of the resonator with the highest resonant frequency.

29. The acoustic microwave filter of claim 28, wherein the frequency difference between a local minimum or a local maximum of a return loss magnitude of the acoustic microwave filter and an edge of the passband is at least 1.25 times the frequency separation of the resonator with the highest resonant frequency.

30. The acoustic microwave filter of claim 28, wherein the frequency difference between a local minimum or a local maximum of a return loss magnitude of the acoustic microwave filter and an edge of the passband is at least two times the frequency separation of the resonator with the highest resonant frequency.

31. The acoustic microwave filter of claim 28, wherein the filter has an insertion loss less than 3 dB.

32. The acoustic microwave filter of claim 28, wherein the plurality of resonators comprises at least two in-line resonators and/or at least two in-shunt resonators.

33. The acoustic microwave filter of claim 28, wherein the plurality of resonators comprises at least one paired in-line resonator and in-shunt resonator.

34. The acoustic microwave filter of claim 28, wherein each of the plurality of resonators is one of a surface acoustic wave (SAW) resonator, a bulk acoustic wave (BAW) resonator, a film bulk acoustic resonator (FBAR), and a microelectromechanical system (MEMS) resonator.