TRANSVERSELY-EXCITED BULK ACOUSTIC RESONATOR SPLIT LADDER FILTER
A filter device is provided that includes a first chip comprising at least one first bulk acoustic resonator including a first piezoelectric material between a first upper conductor and a first lower conductor; a second chip comprising at least one second bulk acoustic resonator including a second piezoelectric material between a second upper conductor and a second lower conductor; and a circuit card coupled to the first chip and the second chip. A thickness of the first piezoelectric material is greater than a thickness of the second piezoelectric material.
1 . A filter device comprising:
a first chip comprising at least one first bulk acoustic resonator including a first piezoelectric material between a first upper conductor and a first lower conductor;
a second chip comprising at least one second bulk acoustic resonator including a second piezoelectric material between a second upper conductor and a second lower conductor; and
a circuit card coupled to the first chip and the second chip,
wherein a thickness of the first piezoelectric material is greater than a thickness of the second piezoelectric material.
2 . The filter device of claim 1 , wherein:
the first chip includes series resonators of a ladder filter circuit, and
the second chip includes shunt resonators of the ladder filter circuit.
3 . The filter device of claim 1 , wherein the circuit card comprises at least one electrical connection between the first bulk acoustic resonator of the first chip and the second bulk acoustic resonator of the second chip.
4 . The filter device of claim 1 , wherein the first piezoelectric material and the second piezoelectric material differ in at least one of a material and an orientation of a crystalline axis of the material.
5 . The filter device of claim 1 , wherein the first upper conductor and the second upper conductor differ in one or more of a thickness of the first upper conductor and the second upper conductor being different, or a material of the first upper conductor and the second upper conductor being different.
6 . The filter device of claim 1 , wherein the first lower conductor and the second lower conductor differ in one or more of a thickness of the first lower conductor and the second lower conductor being different, or a material of the first lower conductor and the second lower conductor being different.
7 . The filter device of claim 1 , wherein:
the at least one first bulk acoustic resonator is covered with a first dielectric layer, and the at least one second bulk acoustic resonator is covered with a second dielectric layer; and
the first dielectric layer and the second dielectric layer differ in one or more of a thickness of the first dielectric layer and the second dielectric layer being different, or a material of the first dielectric layer and the second dielectric layer being different.
8 . The filter device of claim 1 , wherein the first chip further comprises a first base and a first cavity in the first base, and wherein at least a portion of each of the first upper conductor, the first piezoelectric material and the first lower conductor forms a diaphragm over the first cavity.
9 . The filter device of claim 8 , wherein the second chip comprises a second base and a second cavity in the second base, and wherein at least a portion of each of the second upper conductor, the second piezoelectric material and the second lower conductor forms a diaphragm over the second cavity.
10 . The filter device of claim 9 , wherein the at least one first bulk acoustic resonator and the at least one second bulk acoustic resonator differ in one or more of a material of the first base and second base being different, or a thickness of the first base being different than a thickness of the second base.
11 . The filter device of claim 1 , wherein the first chip further comprises a first base, and a first acoustic Bragg reflector between the first lower conductor and the first base.
12 . The filter device of claim 11 , wherein the second chip further comprises a second base, and a second acoustic Bragg reflector between the second lower conductor and the second base.
13 . The filter device of claim 12 , wherein the at least one first bulk acoustic resonator and the at least one second bulk acoustic resonator differ in one or more of a material of the first base and second base being different, or a thickness of the first base being different than a thickness of the second base.
14 . A filter device comprising:
at least one first bulk acoustic resonator on a first chip comprising:
a first non-piezoelectric base;
a first dielectric layer on the first non-piezoelectric base;
a first lower conductor on the first dielectric layer; and
a first piezoelectric material between a first upper conductor and the first lower conductor;
at least one second bulk acoustic resonator on a second chip comprising:
a second non-piezoelectric base;
a second dielectric layer on the second non-piezoelectric base;
a second lower conductor on the second dielectric layer; and
a second piezoelectric material between a second upper conductor and the second lower conductor; and
a circuit card electrically coupling the first chip to the second chip,
wherein a thickness of the first piezoelectric material is greater than a thickness of the second piezoelectric material.
15 . The filter device of claim 14 , wherein:
the at least one first bulk acoustic resonator is a series resonator of a ladder filter circuit, and
the at least one second bulk acoustic resonator is a shunt resonator of the ladder filter circuit.
16 . The filter device of claim 14 , wherein the circuit card comprises at least one electrical connection between the at least one first bulk acoustic resonator of the first chip and the at least one second bulk acoustic resonator of the second chip.
17 . The filter device of claim 14 , wherein the first piezoelectric material and the second piezoelectric material differ in at least one of a material and an orientation of a crystalline axis of the material.
18 . The filter device of claim 14 , wherein the first upper conductor and the second upper conductor differ in one or more of a thickness of the first upper conductor and the second upper conductor being different, or a material of the first upper conductor and the second upper conductor being different.
19 . The filter device of claim 14 , wherein the first lower conductor and the second lower conductor differ in one or more of a thickness of the first lower conductor and the second lower conductor being different, or a material of the first lower conductor and the second lower conductor being different.
20 . The filter device of claim 14 , wherein:
the first upper conductor is covered with a third dielectric layer, and the upper conductor is covered with a fourth dielectric layer; and
the third dielectric layer and the fourth dielectric layer differ in one or more of a thickness of the third dielectric layer and the fourth dielectric layer being different, or a material of the third dielectric layer and the fourth dielectric layer being different.
21 . The filter device of claim 14 , wherein the at least one first bulk acoustic resonator and the at least one second bulk acoustic resonator differ in one or more of a material of the first non-piezoelectric base and second non-piezoelectric base being different, or a thickness of the first non-piezoelectric base being different than a thickness of the second non-piezoelectric base.
22 . The filter device of claim 14 , wherein the at least one first bulk acoustic resonator comprises a first cavity in at least a portion of the first non-piezoelectric base and the first dielectric layer, and the at least one second bulk acoustic resonator comprises a second cavity in at least a portion of the second non-piezoelectric base and the second dielectric layer.
23 . The filter device of claim 14 , wherein the at least one first bulk acoustic resonator comprises a first acoustic Bragg reflector between the first lower conductor and the first non-piezoelectric base, and the at least one second bulk acoustic resonator comprises a second acoustic Bragg reflector between the second lower conductor and the second non-piezoelectric base.