Abstract:
A micromachined device for selectively switching an optical fiber between a first and a second position includes a working leg that undergoes a greater degree of thermal expansion than a second leg with the conduction of an electrical current through the two legs. In a preferred embodiment, the working leg has a cross-sectional area that is less than that of the second leg, thereby presenting a greater electrical resistance to the current flow. The legs are each fixed to a substrate at first ends and are interconnected at second ends that are free to move relative to the substrate. The difference in electrical resistance provides a differential in thermal expansion, as the working leg lengthens to a greater degree than the second leg. The working leg deforms the second leg and the optical fiber is pressed into a second position until current flow is terminated. In another embodiment, the differential in thermal expansion is created by ensuring that the second leg has less thermal isolation from the substrate than the thermal isolation of the working leg from the substrate.
Abstract:
An integration of a micromachined actuator and a signal transmission structure includes a thermal actuator on a side of a displaceable signal line opposite to a fixed signal line. The actuator includes first and second legs. The first leg has a cross-sectional area greater than the second leg, providing a differential in electrical resistance. As current is channeled through the legs, the second leg will elongate more and will deflect both of the legs. The deflection is in a direction to press the displaceable signal line into signal communication with the fixed signal line. Optionally, a thermally operated reset actuator can be positioned to provide a mechanical return of the displaceable signal line. In a preferred embodiment, a microwave transmission environment is provided.
Abstract:
A micromachined signal switch for vertical displacement includes a fixed substrate having at least one signal line and includes an actuator substrate that is thermally actuated to selectively connect a second signal line to the first signal line. The actuator substrate includes a plurality of legs constructed of materials having sufficiently different coefficients of thermal expansion to create stresses that arc the legs when the legs are subjected to elevated temperatures. In the preferred embodiment, a first material for forming the legs is silicon and a second material is a metal, such as electroplated nickel. A displaceable contact region may be formed integrally with the actuator substrate, but the contact region is preferably a region of an interposer substrate between the fixed substrate and the actuator substrate. The displaceable contact region has a raised position in which the signal line on the fixed substrate is "off" and has a lowered position in which a conductive member on the contact region is positioned to provide electrical communication to the signal line.
Abstract:
An acoustic resonator device includes a composite first electrode on a substrate, a piezoelectric layer on the composite electrode, and a second electrode on the piezoelectric layer. The first electrode includes a buried temperature compensating layer having a positive temperature coefficient. The piezoelectric layer has a negative temperature coefficient, and thus the positive temperature coefficient of the temperature compensating layer offsets at least a portion of the negative temperature coefficient of the piezoelectric layer.
Abstract:
An acoustic resonator device includes an annular acoustic resonator, a heater coil and a heat sensor. The annular acoustic resonator is positioned over a trench formed in a substrate of the acoustic resonator device. The heater coil is disposed around a perimeter of the annular acoustic resonator, the heater coil including a resistor configured to receive a heater current. The heat sensor is configured to adjust the heater current in response to a temperature of the heater coil.
Abstract:
Disclosed is an acoustic resonator that includes a substrate, a first electrode, a layer of piezoelectric material, a second electrode, and an alternating frame region. The first electrode is adjacent the substrate, and the first electrode has an outer perimeter. The piezoelectric layer is adjacent the first electrode. The second electrode is adjacent the piezoelectric layer and the second electrode has an outer perimeter. The alternating frame region is on one of the first and second electrodes.
Abstract:
A method for fabricating a resonator, and in particular, a thin film bulk acoustic resonator (FBAR), and a resonator embodying the method are disclosed. An FBAR is fabricated on a substrate by reducing mass from a top electrode layer. For a substrate having multiple resonators, mass is reduced from only selected resonator to provide resonators having different resonance frequencies on the same substrate.
Abstract:
A method for fabricating a resonator, and in particular, a thin film bulk acoustic resonator (FBAR), and a resonator embodying the method are disclosed. An FBAR is fabricated on a substrate by mass loading piezoelectric (PZ) layer between two electrodes. For a substrate having multiple resonators, only selected resonator is mass loaded to provide resonators having different resonance frequencies on the same substrate.
Abstract:
A method for fabricating a resonator, and in particular, a thin film bulk acoustic resonator (FBAR), and a resonator embodying the method are disclosed. An FBAR is fabricated on a substrate by introducing a mass loading electrode to a bottom electrode layer. For a substrate having multiple resonators, mass loading bottom electrode is introduced for only selected resonator to provide resonators having different resonance frequencies on the same substrate.