Patent ID: 7391286

Claim:
A transformer comprising: a first and a second stacked bulk acoustic resonator (SBAR), each SBAR including, a first and a second film bulk acoustic resonator (FBAR), each FBAR including a pair of opposed planar electrodes and a layer of piezoelectric material, an acoustic decoupler interposing the first and second FBARs, a first electrical circuit connecting first FBAR of the first SBAR to the second FBAR of the second SBAR, the first electrical circuit connecting the first FBAR of the first SBAR to the second FBAR of the second SBAR in parallel; a second electrical circuit connecting the second FBAR of the first SBAR to the first FBAR of the second SBAR, the second electrical circuit connecting the second FBAR of the first SBAR to the first FBAR of the second SBAR in series; and a first shunt inductor electrically connected to the first SBAR.