US 12,341,491 B2
Loaded resonators for adjusting frequency response of acoustic wave resonators
Tapani Makkonen, Espoo (FI); Markku Ylilammi, Espoo (FI); Tuomas Pensala, Espoo (FI); and James Dekker, Espoo (FI)
Assigned to Teknologian tutkimuskeskus VTT Oy, Espoo (FI)
Filed by Teknologian tutkimuskeskus VTT Oy, Espoo (FI)
Filed on Mar. 24, 2022, as Appl. No. 17/703,185.
Application 17/703,185 is a continuation of application No. 17/034,711, filed on Sep. 28, 2020, granted, now 11,290,083.
Application 17/034,711 is a continuation of application No. 16/125,632, filed on Sep. 7, 2018, granted, now 10,790,801, issued on Sep. 29, 2020.
Prior Publication US 2022/0216852 A1, Jul. 7, 2022
Int. Cl. H03H 9/54 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01)
CPC H03H 9/547 (2013.01) [H03H 9/132 (2013.01); H03H 9/173 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of fabricating an acoustic wave filter device, the method comprising:
forming an acoustic wave filter element and a first resonator coupled to the acoustic wave filter element,
wherein the acoustic wave filter element comprises interdigitated input electrodes and output electrodes located on a top surface of a piezoelectric layer and a counter-electrode on a bottom surface of the piezoelectric layer, wherein the acoustic wave filter element provides a response with a sideband at a sideband frequency range, and
wherein the first resonator comprises a first resonator electrode on the top surface of the piezoelectric layer and a first resonator counter-electrode on the bottom surface of the piezoelectric layer, the first resonator having a first notch in resonator impedance at a first resonance frequency; and
tuning the first resonance frequency to fall within the sideband frequency range to suppress the sideband by
depositing a first mass load on top of the first resonator electrode to reduce the first resonance frequency, or
partly removing the first resonator electrode to increase the first resonance frequency.