BAW Resonator Filter Bandwidth and Out-of-Band Frequency Rejection
AssigneeMaxim Integrated Products, Inc.
InventorsCarlton Stuebing, Guilaume Bouche
Life of this patent
Estimating the term…
Abstract
Embodiments of the present invention provide systems, devices and methods for improving both the bandwidth of a BAW resonator bandpass filter and the suppression of out-of-band frequencies above the passband. In various embodiments of the invention, blocker inductors are located in series between the filter input and the filter output to realize both bandwidth enhancement and improved out-of-band frequency rejection. For example, a first blocker inductor may be located at the input and a second blocker inductor may be located at the output of a BAW resonator bandpass filter.
Claims20
A bulk acoustic wave (“BAW”) resonator filter, comprising:
- an input of the BAW resonator filter for receiving an electrical signal;
- a 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 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;
- and
- 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.
A bulk acoustic wave (“BAW”) resonator filter, comprising:
- an input of the BAW resonator filter for receiving an electrical signal;
- a first series BAW resonator, coupled to receive the electrical signal, 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 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.
A BAW resonator filter comprising:
- a serial resonant path, coupled between an input and an output of the BAW resonator filter, having a plurality of serial BAW resonators that at least partially define a passband of the BAW resonator filter;
- at least one shunt resonant path, coupled between the serial resonant path and ground, having at least one shunt BAW resonators that at least partially define an upper edge of the passband of the BAW resonator filter;
- a first blocker inductor, coupled within the serial resonant path, that improve rejection of signal frequencies outside of the passband;
- and
- wherein the width of the passband is improved relative to a ratio of an inductance of a helper inductor and an inductance of a serial resonant inductor.
Dependencies are inferred from the claim text.