# US 2025/0096776 A1 · Bulk acoustic wave resonator having multiple resonant frequencies > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0096776 A1 - Document ID: US20250096776A1 - Status: Published application - Kind: A1 - Application number: 18/961,069 - Filed: 2024-11-26 - Published: 2025-03-20 - Earliest claimed: 2020-12-23 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Yiliu Wang; Jiansong Liu; Tomoya Komatsu - Web page: https://patentgrep.com/patent/US20250096776A1 ## CPC - H03H 9/568: {consisting of a ladder configuration} - H03H 9/173: {Air-gaps} - H03H 9/175: {Acoustic mirrors} - H03H 9/205: having multiple resonators (crystal tuning forks H03H9/21) - H03H 9/547: {Notch filters, e.g. notch BAW or thin film resonator filters} - H03H 9/564: {implemented with thin-film techniques} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract Aspects of this disclosure relate to an acoustic wave filter that includes a shunt a bulk acoustic wave resonator having a plurality of resonant frequencies that impact a passband of the acoustic wave filter. Related bulk acoustic wave resonators, radio frequency modules, wireless communication devices, and methods of filtering radio frequency signals are disclosed. ## Claims ### Claim 1 An acoustic wave filter configured to filter a radio frequency signal and having a passband, the acoustic wave filter comprising: a bulk acoustic wave resonator having at least a first resonant frequency corresponding to a first region and a second resonant frequency corresponding to a second region, the bulk acoustic wave resonator having a first peak conductance at the first resonant frequency and a second peak conductance at the second resonant frequency, and the first resonant frequency and the second resonant frequency both impacting the passband; and a plurality of additional acoustic wave resonators, the plurality of additional acoustic wave resonators and the bulk acoustic wave resonator together configured to filter the radio frequency signal. ### Claim 2 (depends on 1) The acoustic wave filter of claim 1 wherein the second resonant frequency is in a range from 0.9 to 1.1 times the first resonant frequency. ### Claim 3 (depends on 1) The acoustic wave filter of claim 1 wherein the second region surrounds the first region in plan view, and the bulk acoustic wave resonator has less mass loading in the second region than in the first region. ### Claim 4 (depends on 1) The acoustic wave filter of claim 1 wherein the bulk acoustic wave resonator has generally constant mass loading throughout the first region, and the bulk acoustic wave resonator has generally constant mass loading throughout the second region. ### Claim 5 (depends on 4) The acoustic wave filter of claim 4 wherein the second region surrounds the first region in plan view, and the second region has greater mass loading than the first region. ### Claim 6 (depends on 4) The acoustic wave filter of claim 4 wherein the second region surrounds the first region in plan view, and the first region has greater mass loading than the second region. ### Claim 7 (depends on 4) The acoustic wave filter of claim 4 wherein the bulk acoustic wave resonator includes a raised frame structure in a raised frame region that surrounds the first region and the second region in plan view. ### Claim 8 (depends on 1) The acoustic wave filter of claim 1 wherein the bulk acoustic wave resonator is a shunt bulk acoustic wave resonator, the first resonant frequency contributes to forming a lower edge of the passband, the second resonant frequency is greater than the first resonant frequency, and the second resonant frequency is between the first resonant frequency and an upper edge of the passband. ### Claim 9 (depends on 1) The acoustic wave filter of claim 1 wherein the bulk acoustic wave resonator includes a raised frame structure in a raised frame region that surrounds the first region and the second region in plan view. ### Claim 10 (depends on 1) The acoustic wave filter of claim 1 wherein the plurality of additional acoustic wave resonators are bulk acoustic wave resonators. ### Claim 11 (depends on 1) The acoustic wave filter of claim 1 wherein the plurality of additional acoustic wave resonators includes a second bulk acoustic wave resonator having a plurality of resonant frequencies that each impact the passband and are associated with a respective peak conductance of the second bulk acoustic wave resonator. ### Claim 12 An acoustic wave filter configured to filter a radio frequency signal and having a passband, the acoustic wave filter comprising: a bulk acoustic wave resonator including a first region associated with a first resonant frequency, a second region associated with a second resonant frequency that is distinct from the first resonant frequency, and a third region around the first region and the second region, the bulk acoustic wave resonator including a raised frame structure in the third region, and the first resonant frequency and the second resonant frequency both impacting the passband; and a plurality of additional acoustic wave resonators, the plurality of additional acoustic wave resonators and the bulk acoustic wave resonator together configured to filter the radio frequency signal. ### Claim 13 (depends on 12) The acoustic wave filter of claim 12 wherein the second resonant frequency is in a range from 0.9 to 1.1 times the first resonant frequency. ### Claim 14 (depends on 12) The acoustic wave filter of claim 12 wherein the second region surrounds the first region in plan view, and the bulk acoustic wave resonator has less mass loading in the second region than in the first region. ### Claim 15 (depends on 12) The acoustic wave filter of claim 12 wherein the bulk acoustic wave resonator has generally constant mass loading throughout the first region, and the bulk acoustic wave resonator has generally constant mass loading throughout the second region. ### Claim 16 (depends on 15) The acoustic wave filter of claim 15 wherein the second region surrounds the first region in plan view, and the second region has greater mass loading than the first region. ### Claim 17 (depends on 15) The acoustic wave filter of claim 15 wherein the second region surrounds the first region in plan view, and the first region has greater mass loading than the second region. ### Claim 18 (depends on 12) The acoustic wave filter of claim 12 wherein the plurality of additional acoustic wave resonators are bulk acoustic wave resonators. ### Claim 19 A wireless communication device comprising: an acoustic wave filter having a passband and configured to filter a radio frequency signal, the acoustic wave filter including a bulk acoustic wave resonator having at least a first resonant frequency corresponding to a first region and a second resonant frequency corresponding to a second region, the bulk acoustic wave resonator having a first peak conductance at the first resonant frequency and a second peak conductance at the second resonant frequency, and the first resonant frequency and the second resonant frequency both impacting the passband; an antenna operatively coupled to the acoustic wave filter; a radio frequency amplifier operatively coupled to the acoustic wave filter; and a transceiver in communication with the radio frequency amplifier. ### Claim 20 (depends on 19) The wireless communication device of claim 19 wherein the wireless communication device is a mobile phone.