Acoustic resonator filter structure with tunable shunt coupled resonator filter
An acoustic resonator filter structure with a tunable shunt coupled resonator filter (CRF) is provided. Herein, the acoustic resonator filter structure is a stacked structure that includes a series resonator filter die and a tunable shunt CRF die. By stacking the series resonator filter die and the tunable shunt CRF die according to various embodiments, it is possible to reduce a footprint of the acoustic resonator filter structure, thus making it possible to incorporate multiple acoustic resonator filter structures in an acoustic ladder filter network.
1 . An acoustic resonator filter structure comprising:
a series resonator filter die configured to resonate at a series resonance frequency to pass a signal from an input node to an output node; and
a tunable shunt coupled resonator filter (CRF) die configured to resonate at a tunable parallel resonance frequency to block the signal between the input node and the output node, the tunable shunt CRF die comprises:
a ferroelectric input shunt resonator coupled to the input node and configured to resonate at the tunable parallel resonance frequency;
a ferroelectric output shunt resonator coupled to the output node and configured to resonate at the tunable parallel resonance frequency; and
a coupling layer configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator to thereby modify the tunable parallel resonance frequency.
2 . The acoustic resonator filter structure of claim 1 , wherein the series resonator filter die is disposed atop the tunable shunt CRF die.
3 . The acoustic resonator filter structure of claim 2 , wherein the series resonator filter die comprises:
a ferroelectric series resonator configured to resonate at the series resonance frequency; and
a pair of reflectors provided above and below the ferroelectric series resonator.
4 . The acoustic resonator filter structure of claim 2 , wherein the coupling layer is coupled to a tuning circuit and configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator in response to receiving a tuning voltage from the tuning circuit.
5 . The acoustic resonator filter structure of claim 1 , wherein the series resonator filter die is disposed underneath the tunable shunt CRF die.
6 . The acoustic resonator filter structure of claim 5 , wherein the series resonator filter die comprises:
a ferroelectric series resonator configured to resonate at the series resonance frequency; and
a pair of reflectors provided above and below the ferroelectric series resonator.
7 . The acoustic resonator filter structure of claim 5 , wherein the coupling layer is coupled to a tuning circuit and configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator in response to receiving a tuning voltage from the tuning circuit.
8 . An acoustic ladder filter network comprising a plurality of acoustic resonator filter structures each comprising:
a series resonator filter die configured to resonate at a series resonance frequency to pass a signal from an input node to an output node; and
a tunable shunt coupled resonator filter (CRF) die configured to resonate at a tunable parallel resonance frequency to block the signal between the input node and the output node;
wherein each pair of the plurality of acoustic resonator filter structures is separated by a conventional resonator filter.
9 . A wireless device comprising at least one acoustic resonator filter structure, the at least one acoustic resonator filter structure comprises:
a series resonator filter die configured to resonate at a series resonance frequency to pass a signal from an input node to an output node; and
a tunable shunt coupled resonator filter (CRF) die configured to resonate at a tunable parallel resonance frequency to block the signal between the input node and the output node, the tunable shunt CRF die comprises:
a ferroelectric input shunt resonator coupled to the input node and configured to resonate at the tunable parallel resonance frequency;
a ferroelectric output shunt resonator coupled to the output node and configured to resonate at the tunable parallel resonance frequency; and
a coupling layer configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator to thereby modify the tunable parallel resonance frequency.
10 . The wireless device of claim 9 , wherein:
the series resonator filter die is disposed atop the tunable shunt CRF die;
the series resonator filter die comprises:
a ferroelectric series resonator configured to resonate at the series resonance frequency; and
a pair of reflectors provided above and below the ferroelectric series resonator.
11 . The wireless device of claim 10 , wherein the coupling layer is coupled to a tuning circuit and configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator in response to receiving a tuning voltage from the tuning circuit.
12 . The wireless device of claim 9 , wherein the series resonator filter die is disposed underneath the tunable shunt CRF die.
13 . The wireless device of claim 12 , wherein the series resonator filter die comprises:
a ferroelectric series resonator configured to resonate at the series resonance frequency; and
a pair of reflectors provided above and below the ferroelectric series resonator.
14 . The wireless device of claim 12 , wherein the coupling layer is coupled to a tuning circuit and configured to be polarized relative to the ferroelectric input shunt resonator and the ferroelectric output shunt resonator in response to receiving a tuning voltage from the tuning circuit.
15 . A method for configuring an acoustic ladder filter network comprising:
configuring a series resonator filter die in each of a plurality of acoustic resonator filter structures to resonate at a series resonance frequency to pass a signal from an input node to an output node;
configuring a tunable shunt coupled resonator filter (CRF) die in each of the plurality of acoustic resonator filter structures to resonate at a tunable parallel resonance frequency to block the signal between the input node and the output node; and
separating each pair of the plurality of acoustic resonator filter structures by a conventional resonator filter.