Meltaus, Johanna

Pensala, Tuomas

The invention relates to a laterally coupled bulk acoustic wave (LBAW) filter comprising a vibration layer for carrying bulk acoustic waves, electrode means comprising a first electrode coupled to the vibration layer for exciting to the vibration layer at least one longitudinal wave mode having a first frequency band and one shear wave mode having a second frequency band, and a second electrode coupled to the vibration layer for sensing the filter pass signal, the first and second electrodes being laterally arranged with respect to each other, and an acoustic reflector structure in acoustic connection with the vibration layer. According to the invention, the reflector structure is adapted to acoustically isolate the vibration layer from its surroundings at the first frequency band more efficiently than at the second frequency band for suppressing the effect of the shear wave mode at the second frequency band from the filter pass signal. The invention helps to improve the quality of LBAW filter passbands.Patent family as of 7.10.2021CN104205632 A 20141210 CN201280066944 20121109      EP2777153 A1 20140917 EP20120847501 20121109      EP2777153 A4 20151223 EP20120847501 20121109      EP2777153 B1 20210818 EP20120847501 20121109FI20116113 A 20130512 FI20110006113 20111111      JP2015502065 T2 20150119 JP20140540529T 20121109      JP2018129839 A2 20180816 JP20180052320 20180320      JP6564096 B2 20190821 JP20180052320 20180320      KR101977334 B1 20190510 KR20147015834 20121109      KR20140101773 A 20140820 KR20147015834 20121109      US2014312994 AA 20141023 US20120357220 20121109      US9219466 BB 20151222 US20120357220 20121109      WO13068652 A1 20130516 WO2012FI51096 20121109Link to current patent family on right </p

Laterally coupled bulk acoustic wave filter with improved passband characteristics

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