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Expired Canadian patentCanada

Surface acoustic wave scattering grating

CA 1299732 C · Owner: Bell-Northern Research Ltd. · Inventors: Beggs, Bruce C.; Este, Grantley O.

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A grating is positioned on a surface acoustic wave device on a first axis in-line with the delay line for substantially reducing the amount of energy reflected on that axis to the transmitter and receiver. The grating sits on the first axis at a position between the delay line and one of the edges of the device. The grating is comprised of a parallel series of grating members each oriented so as to extend at a first angle relative to the first axis, the grating members being generally longitudinally bisected by that axis. An optimum value for the first angle is provided by a theoretical analysis, and experimental results are presented. On the experimental device, the grating is defined by a …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted April 28, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 28, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 13, 1989
GrantedApril 28, 1992
Term endedApril 28, 2009
Patent numberCA 1299732 C
Classification (IPC)H01L41/00 +2 more

Timeline

Timeline From CIPO dates

1990199219941996199820002002200420062008Application filedApril 13, 1989Patent grantedApril 28, 1992Term endedApril 28, 2009

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.