Acoustic galvanic isolator incorporating single insulated decoupled stacked bulk acoustic resonator with acoustically-resonant electrical insulator
View Patent ↗Embodiments of the acoustic galvanic isolator comprise a carrier signal source, a modulator connected to receive an information signal and the carrier signal, a demodulator, and an electrically-isolating acoustic coupler connected between the modulator and the demodulator. The acoustic coupler comprises no more than one decoupled stacked bulk acoustic resonator (IDSBAR). An electrically-isolating acoustic coupler based on a single IDSBAR is physically small and is inexpensive to fabricate yet is capable of passing information signals having data rates in excess of 100 Mbit/s and has a substantial breakdown voltage between its inputs and its outputs.
1. An acoustic galvanic isolator, comprising:
a carrier signal source;
a modulator connected to receive an information signal and the carrier signal;
a demodulator; and
connected between the modulator and the demodulator, an electrically-isolating acoustic coupler comprising a single insulating decoupled stacked bulk acoustic resonator (IDSBAR), the IDSBAR comprising an acoustically-resonant electrical insulator.
2. The acoustic galvanic isolator of claim 1 , in which:
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR, and a first acoustic decoupler and a second acoustic decoupler between the FBARs; and
the acoustically-resonant electrical insulator comprises a quarter-wave layer of electrically-insulating material and is located between the first acoustic decoupler and the second acoustic coupler.
3. The acoustic galvanic isolator of claim 1 , in which:
the acoustically-resonant electrical insulator is a first acoustically-resonant electrical insulator;
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR, and, between the FBARs, in order, the first acoustically-resonant electrical insulator, an acoustic decoupler and a second acoustically-resonant electrical insulator; and
each acoustically-resonant electrical insulator is a half-wave acoustically-resonant electrical insulator and comprises a half-wave layer of electrically-insulating material.
4. The acoustic galvanic isolator of claim 1 , in which the acoustically-resonant electrical insulator comprises a layer of electrically-insulating material.
5. The acoustic galvanic isolator of claim 4 , in which the electrically-insulating material comprises one of aluminum nitride and aluminum oxide.
6. The acoustic galvanic isolator of claim 1 , in which:
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR, and an acoustic decoupler; and
the acoustically-resonant electrical insulator and the acoustic decoupler are juxtaposed between the FBARs.
7. The acoustic galvanic isolator of claim 6 , in which the acoustically-resonant electrical insulator is matched in acoustic impedance to the FBARs.
8. The acoustic galvanic isolator of claim 6 , in which the acoustically-resonant electrical insulator differs in acoustic impedance from the FBARs by less than one order of magnitude.
9. The acoustic galvanic isolator of claim 6 , in which the acoustic decoupler comprises an acoustic decoupling layer comprising an acoustic decoupling material.
10. The acoustic galvanic isolator of claim 6 , in which the acoustic decoupling material differs in acoustic impedance from the FBARs by about one order of magnitude.
11. The acoustic galvanic isolator of claim 6 , in which the acoustic decoupler is electrically insulating.
12. The acoustic galvanic isolator of claim 6 , in which the acoustic decoupler comprises an acoustic Bragg structure.
13. The acoustic galvanic isolator of claim 12 , in which the acoustic Bragg structure comprises one or more low acoustic impedance Bragg elements interleaved with high acoustic impedance Bragg elements; and at least one of the Bragg elements is electrically insulating.
14. The acoustic galvanic isolator of claim 12 , in which the acoustic Bragg structure comprises one or more layers of crosslinked polyphenylene polymer interleaved with layers of silicon dioxide.
15. The acoustic galvanic isolator of claim 6 , in which the IDSBAR additionally comprises an additional acoustically-resonant electrical insulator and an additional acoustic decoupler between the FBARs.
16. The acoustic galvanic isolator of claim 1 , additionally comprising an additional acoustically-resonant electrical insulator.
17. A method for galvanically isolating an information signal, the method comprising:
providing an electrically-isolating acoustic coupler comprising a single insulating decoupled stacked bulk acoustic resonator (IDSBAR), the IDSBAR comprising an acoustically-resonant electrical insulator;
providing a carrier signal;
modulating the carrier signal with the information signal to form a modulated electrical signal;
acoustically coupling the modulated electrical signal through the electrically-isolating acoustic coupler; and
recovering the information signal from the modulated electrical signal acoustically coupled through the electrically-isolating acoustic coupler.
18. The method of claim 17 , in which:
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR stacked on the first FBAR, and a first acoustic decoupler and a second acoustic decoupler located between the FBARs; and
the acoustically-resonant electrical insulator comprises a quarter-wave layer of electrically-insulating material and is located between the first acoustic decoupler and the second acoustic coupler.
19. The method of claim 17 , in which:
the acoustically-resonant electrical insulator is a first acoustically-resonant electrical insulator;
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR stacked on the first FBAR, and, between the FBARs, in order, the first acoustically-resonant electrical insulator, an acoustic decoupler and a second acoustically-resonant electrical insulator; and
each acoustically-resonant electrical insulator is a half-wave acoustically-resonant electrical insulator and comprises a half-wave layer of electrically-insulating material.
20. The method of claim 17 , in which the acoustically-resonant electrical insulator comprises a layer of electrically-insulating material.
21. The method of claim 20 , in which the electrically-insulating material comprises one of aluminum nitride or aluminum oxide.
22. The method of claim 17 , in which:
the IDSBAR additionally comprises a first film bulk acoustic resonator (FBAR), a second FBAR and an acoustic decoupler;
the acoustically-resonant electrical insulator and the acoustic decoupler are juxtaposed between the FBARs; and
the coupling comprises:
applying the modulated electrical signal to one of the FBARs, and
receiving the modulated electrical signal from the other of the FBARs.