Acoustic wave resonators and radio frequency elements with isolation
Embodiments of this disclosure relate to reducing coupling between acoustic wave resonators. An isolation region of a substrate can be located between acoustic wave resonators. The isolation region can reduce capacitive coupling through the substrate between the acoustic wave resonators. In certain embodiments, the isolation region can be located between acoustic wave resonators of different filters to thereby increase isolation between the filters.
1. An acoustic wave resonator assembly with reduced capacitive coupling, the acoustic wave resonator assembly comprising:
a first acoustic wave resonator;
a second acoustic wave resonator, the first acoustic wave resonator and the second acoustic wave resonator sharing a substrate; and
an isolation region of the substrate arranged to cause capacitive coupling between the first acoustic wave resonator and the second acoustic wave resonator to be reduced, the isolation region being a solid region.
2. The acoustic wave resonator assembly of claim 1 wherein the isolation region is formed by applying laser light to the substrate.
3. The acoustic wave resonator assembly of claim 1 wherein the substrate is a piezoelectric substrate having a crystalline structure that is disrupted in the isolation region.
4. The acoustic wave resonator assembly of claim 1 wherein the isolation region is an amorphous region of the substrate.
5. The acoustic wave resonator assembly of claim 1 wherein the isolation region is a polycrystalline region of the substrate.
6. The acoustic wave resonator assembly of claim 1 wherein the isolation region extends through only part of a thickness of the substrate.
7. The acoustic wave resonator assembly of claim 1 wherein the first acoustic wave resonator is a surface acoustic wave resonator.
8. The acoustic wave resonator assembly of claim 1 wherein the first acoustic wave resonator includes a first interdigital transducer electrode, and the second acoustic wave resonator includes a second interdigital transducer electrode.
9. The acoustic wave resonator assembly of claim 1 wherein the substrate is a lithium based piezoelectric substrate.
10. The acoustic wave resonator assembly of claim 1 wherein the first acoustic wave resonator is included in a different acoustic wave filter than the second acoustic wave resonator.
11. The acoustic wave resonator assembly of claim 1 wherein the first acoustic wave resonator is included in a transmit filter and the second acoustic wave resonator is included in a receive filter.
12. The acoustic wave resonator assembly of claim 11 wherein the transmit filter and the receive filter are coupled to each other at a common node and included in a multiplexer.
13. The acoustic wave resonator assembly of claim 1 wherein the first acoustic wave resonator and the second acoustic wave resonator are included in a single acoustic wave filter.
14. A front end module with acoustic wave resonators with reduced capacitive coupling, the front end module comprising:
an acoustic wave filter assembly including a first acoustic wave resonator, a second acoustic wave resonator sharing a substrate with the first acoustic wave resonator, and an isolation region of the substrate arranged to cause capacitive coupling between the first acoustic wave resonator and the second acoustic wave resonator to be reduced, the isolation region being a solid region;
a radio frequency amplifier; and
a package enclosing the acoustic wave filter assembly and the radio frequency amplifier.
15. A radio frequency component with reduced capacitive coupling between radio frequency elements, the radio frequency component comprising:
a first radio frequency element on a monolithic substrate;
a second radio frequency element on the monolithic substrate; and
an isolation region of the monolithic substrate arranged to cause capacitive coupling between the first radio frequency element and the second radio frequency element to be reduced, the isolation region being a solid region and having a dielectric constant that is less that a dielectric constant of regions under the first radio frequency element and the second radio frequency element.
16. The radio frequency component of claim 15 wherein the first radio frequency element is one of a filter, a radio frequency amplifier, a radio frequency switch, or a coupler.
17. The radio frequency component of claim 15 wherein the monolithic substrate has a crystalline structure that is disrupted in the isolation region.
18. The radio frequency component of claim 15 wherein the dielectric constant of the regions under the first radio frequency element and the second radio frequency element is at least 10.
19. The radio frequency component of claim 15 wherein the dielectric constant of the regions under the first radio frequency element and the second radio frequency element is in a range from 30 to 100.
20. The radio frequency component of claim 15 wherein the isolation region is formed by applying laser light to the monolithic substrate.