Film acoustically-coupled transformers with two reverse c-axis piezoelectric elements
First Claim
1. A method of making an acoustically-coupled transformer, the method comprising:
- fabricating a first stacked bulk acoustic resonator (SBAR) and a second SBAR, the fabricating comprising;
forming lower film bulk acoustic resonators (FBARs) and upper FBARs, each of the FBARs comprising opposed planar electrodes and a piezoelectric element therebetween, the piezoelectric element characterized by a c-axis, the forming comprising setting the c-axes of the piezoelectric elements of the lower FBARs opposite in direction and setting the c-axes of the upper FBARs opposite in direction, and locating an acoustic decoupler between the lower FBAR and the upper FBAR of each SBAR;
electrically connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR; and
electrically connecting the upper FBAR of the first SBAR to the upper FBAR of the second SBAR.
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Abstract
Embodiments of an acoustically-coupled transformer have a first stacked bulk acoustic resonator (SBAR) and a second SBAR. Each of the SBARs has a lower film bulk acoustic resonator (FBAR) and an upper FBAR, and an acoustic decoupler between the FBARs. The upper FBAR is stacked atop the lower FBAR. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element is characterized by a c-axis. The c-axes of the piezoelectric elements of the lower FBARs are opposite in direction, and the c-axes of the piezoelectric elements of the upper FBARs are opposite in direction. The transformer additionally has a first electrical circuit connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR, and a second electrical circuit connecting the upper FBAR of the first SBAR to the upper FBARs of the second SBAR.
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Citations
13 Claims
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1. A method of making an acoustically-coupled transformer, the method comprising:
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fabricating a first stacked bulk acoustic resonator (SBAR) and a second SBAR, the fabricating comprising;
forming lower film bulk acoustic resonators (FBARs) and upper FBARs, each of the FBARs comprising opposed planar electrodes and a piezoelectric element therebetween, the piezoelectric element characterized by a c-axis, the forming comprising setting the c-axes of the piezoelectric elements of the lower FBARs opposite in direction and setting the c-axes of the upper FBARs opposite in direction, and locating an acoustic decoupler between the lower FBAR and the upper FBAR of each SBAR;
electrically connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR; and
electrically connecting the upper FBAR of the first SBAR to the upper FBAR of the second SBAR. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification