Patent ID: 7242270
Filing Date: 2007-07-10
Classification: H03H

Abstract:
1. A band-pass filter, comprising: first terminals; second terminals; a first decoupled stacked bulk acoustic resonator (DSBAR), a second DSBAR, a third DSBAR, and a fourth DSBAR, each DSBAR comprising a first film bulk acoustic resonator (FBAR), a second FBAR and an acoustic decoupler between the FBARs, each FBAR comprising opposed planar electrodes and a piezoelectric element between the electrodes; a first electrical circuit connecting the first DSBAR and the second DSBAR in series between the first terminals and the second terminal; and a second electrical circuit configured to connect the third DSBAR and the fourth DSBAR in series between the first terminals and the second terminals; and one of the first electrical circuit and the second electrical circuit is phase-inverting relative to the other.