# US 11,909,377 B2 · Acoustic wave filter with acoustic velocity adjustment structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,377 B2 - Document ID: US11909377B2 - Status: Granted - Kind: B2 - Application number: 17/099,522 - Filed: 2020-11-16 - Published: 2021-05-27 - Granted: 2024-02-20 - Earliest claimed: 2019-11-21 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Joshua James Caron; Rei Goto; Benjamin Paul Abbott; Hiroyuki Nakamura - Web page: https://patentgrep.com/patent/US11909377B2 ## CPC - H03H 9/02685: {Grating lines having particular arrangements} - H03F 3/195: in integrated circuits - H03F 3/245: {with semiconductor devices only} - H03H 9/02574: {of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate} - H03H 9/02834: {of temperature influence (cut angles H03H9/02543)} - H03H 9/02842: {of reflections (H03H9/6406 takes precedence)} - H03H 9/145: for networks using surface acoustic waves - H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)} - H03H 9/6406: {Filters characterised by a particular frequency characteristic} - H03H 9/6436: {having one acoustic track only} - H03H 9/6483: {Ladder SAW filters} - H04B 1/40: Circuits - H03F 2200/111: the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not - H03F 2200/451: the amplifier being a radio frequency amplifier - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H03F: AMPLIFIERS - H04B: TRANSMISSION ## Abstract Aspects of this disclosure relate to a surface acoustic wave filter with an acoustic velocity adjustment structure. The surface acoustic wave filter can include a first interdigital transducer electrode disposed on a piezoelectric layer, an acoustic reflector disposed on the piezoelectric layer, and a second interdigital transducer electrode disposed on the piezoelectric layer. The second interdigital transducer electrode is longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector. The acoustic velocity adjustment structure can be positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode. The acoustic velocity adjustment structure can be arranged to increase an acoustic wave propagation velocity in a first region that includes the gap relative to a second region over at least a portion of the first interdigital transducer electrode. ## Claims ### Claim 1 A multi-mode surface acoustic wave filter comprising: a first interdigital transducer electrode on a piezoelectric layer; an acoustic reflector on the piezoelectric layer; a second interdigital transducer electrode on the piezoelectric layer, the second interdigital transducer electrode longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector; and an acoustic velocity adjustment structure positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode, the acoustic velocity adjustment structure arranged to increase an acoustic wave propagation velocity in a first region that includes the gap relative to a second region over at least a portion of the first interdigital transducer electrode. ### Claim 2 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 wherein the acoustic velocity adjustment structure includes a high speed layer over the first region to increase the acoustic wave propagation velocity in the first region. ### Claim 3 (depends on 2) The multi-mode surface acoustic wave filter of claim 2 wherein the high speed layer includes a silicon nitride layer. ### Claim 4 (depends on 2) The multi-mode surface acoustic wave filter of claim 2 wherein the high speed layer includes an aluminum oxide layer. ### Claim 5 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 further comprising a temperature compensation layer over the piezoelectric layer. ### Claim 6 (depends on 5) The multi-mode surface acoustic wave filter of claim 5 wherein the acoustic velocity adjustment structure is at least partially embedded in the temperature compensation layer. ### Claim 7 (depends on 5) The multi-mode surface acoustic wave filter of claim 5 wherein the acoustic velocity adjustment structure is at least partially disposed on the temperature compensation layer. ### Claim 8 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 wherein the second region includes a first sub-region and a second sub-region, the first sub-region defined over at least the portion of the first interdigital transducer electrode, the second sub-region defined over at least a portion of the second interdigital transducer electrode, and the acoustic wave propagation velocity in the first sub-region and the acoustic wave propagation velocity in the second sub-region being approximately the same. ### Claim 9 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 further comprising a third region over at least a portion of the acoustic reflector, the acoustic velocity adjustment structure including a low speed layer over the third region, the low speed layer configured to decrease the acoustic wave propagation velocity in the third region relative to the second region. ### Claim 10 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 further comprising a third interdigital transducer electrode longitudinally coupled to the first interdigital transducer electrode such that the first interdigital transducer electrode is positioned between the third interdigital transducer electrode and the second interdigital transducer electrode. ### Claim 11 (depends on 10) The multi-mode surface acoustic wave filter of claim 10 further comprising a second acoustic reflector longitudinally arranged such that the third interdigital transducer electrode is positioned between the second acoustic reflector and the first interdigital transducer electrode. ### Claim 12 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 wherein the first interdigital transducer electrode and the second interdigital transducer electrode have a pitch variation of no greater than 5 percent. ### Claim 13 (depends on 1) The multi-mode surface acoustic wave filter of claim 1 wherein the first region includes a portion of the first interdigital transducer electrode, wherein the portion of the first interdigital transducer electrode is less than one third of a length of the first interdigital transducer electrode along a direction perpendicular to an aperture direction. ### Claim 14 A radio frequency module comprising: a filter including a multi-mode surface acoustic wave filter having a first interdigital transducer electrode on a piezoelectric layer, an acoustic reflector on the piezoelectric layer, a second interdigital transducer electrode on the piezoelectric layer, and an acoustic velocity adjustment structure positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode, the second interdigital transducer electrode longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector, the acoustic velocity adjustment structure arranged to increase an acoustic wave propagation velocity in a first region that includes the gap relative to a second region over at least a portion of the first interdigital transducer electrode; and a radio frequency circuit element coupled to the filter, the filter and the radio frequency circuit element being enclosed within a common module package. ### Claim 15 (depends on 14) The radio frequency module of claim 14 wherein the radio frequency circuit element is a radio frequency amplifier arranged to amplify a radio frequency signal. ### Claim 16 (depends on 14) The radio frequency module of claim 14 wherein the radio frequency circuit element is a switch configured to selectively couple the filter to a port of the radio frequency module. ### Claim 17 A wireless communication device comprising: a filter including a multi-mode surface acoustic wave filter having a first interdigital transducer electrode on a piezoelectric layer, an acoustic reflector on the piezoelectric layer, a second interdigital transducer electrode on the piezoelectric layer, and an acoustic velocity adjustment structure positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode, the second interdigital transducer electrode longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector, the acoustic velocity adjustment structure arranged to increase an acoustic wave propagation velocity in a first region that includes the gap relative to a second region over at least a portion of the first interdigital transducer electrode; an antenna operatively coupled to the filter; a radio frequency amplifier operatively coupled to the multi-mode surface acoustic wave filter and configured to amplify a radio frequency signal; and a transceiver in communication with the radio frequency amplifier. ### Claim 18 (depends on 17) The wireless communication device of claim 17 further comprising a baseband processor in communication with the transceiver. ### Claim 19 (depends on 17) The wireless communication device of claim 17 wherein the filter is included in a radio frequency front end. ### Claim 20 (depends on 17) The wireless communication device of claim 17 wherein the filter is included in a diversity receive module.