Contour mode resonators with acoustic reflectors
First Claim
1. A microelectromechanical (MEM) resonator, comprising:
- a substrate;
an acoustic resonator suspended on the substrate to produce a resonant acoustic signal in response to an electrical actuation; and
an acoustic reflector located between the acoustic resonator and the substrate to provide an acoustic isolation of the acoustic resonator, with the acoustic reflector being formed as a cantilevered plate extending substantially parallel to the substrate, and with the acoustic reflector further comprising a plurality of elongate regions of two different materials arranged side-by-side in an alternating arrangement.
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Accused Products
Abstract
A microelectromechanical (MEM) resonator is disclosed which has a linear or ring-shaped acoustic resonator suspended above a substrate by an acoustic reflector. The acoustic resonator can be formed with a piezoelectric material (e.g. aluminum nitride, zinc oxide or PZT), or using an electrostatically-actuated material. The acoustic reflector (also termed an acoustic mirror) uses alternating sections of a relatively low acoustic impedance ZL material and a relatively high acoustic impedance ZH material to isolate the acoustic resonator from the substrate. The MEM resonator, which can be formed on a silicon substrate with conventional CMOS circuitry, has applications for forming oscillators, rf filters, and acoustic sensors.
36 Citations
26 Claims
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1. A microelectromechanical (MEM) resonator, comprising:
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a substrate; an acoustic resonator suspended on the substrate to produce a resonant acoustic signal in response to an electrical actuation; and an acoustic reflector located between the acoustic resonator and the substrate to provide an acoustic isolation of the acoustic resonator, with the acoustic reflector being formed as a cantilevered plate extending substantially parallel to the substrate, and with the acoustic reflector further comprising a plurality of elongate regions of two different materials arranged side-by-side in an alternating arrangement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A microelectromechanical (MEM) resonator, comprising:
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a substrate; an acoustic resonator suspended on the substrate and having a ring shape, with the acoustic resonator producing a resonant acoustic signal in response to an electrical actuation thereof; and an acoustic reflector located between the acoustic resonator and the substrate to provide an acoustic isolation of the acoustic resonator, with the acoustic reflector having a ring shape and further comprising a plurality of nested rings of two different alternating materials. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A microelectromechanical (MEM) resonator, comprising:
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a substrate having a cavity formed therein; an acoustic reflector formed as a plate and suspended at least partially over the cavity, and further comprising a plurality of elongate regions of a first material and a second material arranged side-by-side, with each elongate region having a width substantially equal to one-quarter of an acoustic wavelength; and an acoustic resonator attached to the acoustic reflector and suspended over the cavity to produce a resonant acoustic signal, with the acoustic resonator being substantially acoustically isolated from the substrate by the acoustic reflector. - View Dependent Claims (22, 23, 24, 25)
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26. A microelectromechanical (MEM) resonator, comprising:
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a substrate; a ring resonator extending outward over a cavity formed in the substrate to generate or detect a resonant acoustic signal; and an acoustic reflector located between the ring resonator and the substrate to acoustically decouple the ring resonator from the substrate, with the acoustic reflector further comprising a plurality of nested rings having two different alternating acoustic impedances, and with a width of each nested ring being substantially equal to a one-quarter wavelength of the resonant acoustic signal.
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Specification