Invalidity dossier
US 7936553
Capacitors adapted for acoustic resonance cancellation
Current assignee: NXP USA Inc
Added 9/23/2026, 10:57:19 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 7,936,553 B2
Title: Capacitors adapted for acoustic resonance cancellation
Patent number / application: US 7,936,553 B2; application US 11/726,458, filed 2007-03-22; granted 2011-05-03. Publication US 2008/0232023 A1. Legal status listed as Active, with adjusted expiration 2029-11-28.
Inventors: James Oakes, James Martin, Andrey Kozyrev, Alexandr Prudan.
Assignee: Original assignee Paratek Microwave Inc.; current assignee listed as NXP USA Inc. (The source notes listed assignees "may be inaccurate.")
Purpose: Voltage tunable (ferroelectric/BST) varactors tune capacitance with applied bias, but ferroelectric materials are also electrostrictive: an AC signal on a biased capacitor produces acoustic vibrations, and at frequencies set by layer thicknesses and materials the acoustic response becomes resonant, raising loss (drops in Q) at frequencies up to many GHz.
Plain-language scope: The patent teaches multilayered tunable dielectric capacitors arranged so acoustic vibrations cancel rather than accumulate. Tunable dielectric layers are stacked adjacent to one another, sharing a common electrode between layers, so that a vibration in one layer couples to an anti-phase vibration in the neighboring layer. In embodiments, DC bias is arranged so that equal numbers of tunable dielectric layers are biased positively and negatively. Related embodiments connect at least two capacitors in series to an RF signal, with adjacent electrodes positioned to vibrate in opposite phase (with DC bias applied across them, or in opposite directions), including multiple single-layer capacitors placed in close lateral proximity and acoustically coupled. The stated result is reduced acoustic loss and improved Q, and avoidance of loss regions that otherwise make the capacitor unusable in certain frequency ranges.
Source: https://patents.google.com/patent/US7936553/en
What the excerpt does not establish: It provides no claims text, no detailed description of fabrication, dimensions, materials, or measured numerical results beyond the qualitative figures described (e.g., resonance locations near 1.5, 1.7, 1.85, and 2.8 GHz), no filing/priority relationships beyond listings, and no evidence of validity, enforceability, or scope of any specific claim; the text is explicitly an excerpt with omitted portions.
Generated 10/1/2026, 9:54:04 PM
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Assignment history
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Prior art
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Obviousness
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