Patent ID: 7646265

Claim:
A bulk acoustic wave (“BAW”) resonator filter, comprising: an input of the BAW resonator filter for receiving an electrical signal; a first blocker inductor, coupled to the input, that increases a bandwidth associated with the BAW resonator filter and improves above-band frequency rejection by the BAW resonator filter; a first series BAW resonator, coupled to the first blocker inductor, that at least partially defines a series resonant path across the BAW resonator filter; a first shunt BAW resonator, coupled to an output of the first series BAW resonator, that at least partially defines a first shunt resonant path in the BAW resonator filter; a first helper inductor, coupled between the first shunt BAW resonator and ground, that defines a first additional resonant frequency that improves rejection of out-of-band frequencies in the BAW resonator filter; a second series BAW resonator, coupled between the first series BAW resonator and an output of the BAW resonator filter, that further at least partially defines the series resonant path across the BAW resonator filter; and a second blocker inductor, coupled between the second series BAW resonator and the output of the BAW resonator filter, that further increases the bandwidth associated with the BAW resonator filter and further improves out-of-band frequency rejection by the BAW resonator filter.